WorldWideScience

Sample records for submillimeter wavelengths object

  1. Superconductor Semiconductor Research for NASA's Submillimeter Wavelength Missions

    Science.gov (United States)

    Crowe, Thomas W.

    1997-01-01

    Wideband, coherent submillimeter wavelength detectors of the highest sensitivity are essential for the success of NASA's future radio astronomical and atmospheric space missions. The critical receiver components which need to be developed are ultra- wideband mixers and suitable local oscillator sources. This research is focused on two topics, (1) the development of reliable varactor diodes that will generate the required output power for NASA missions in the frequency range from 300 GHZ through 2.5 THz, and (2) the development of wideband superconductive mixer elements for the same frequency range.

  2. Dielectric Covered Planar Antennas at Submillimeter Wavelengths for Terahertz Imaging

    Science.gov (United States)

    Chattopadhyay, Goutam; Gill, John J.; Skalare, Anders; Lee, Choonsup; Llombart, Nuria; Siegel, Peter H.

    2011-01-01

    Most optical systems require antennas with directive patterns. This means that the physical area of the antenna will be large in terms of the wavelength. When non-cooled systems are used, the losses of microstrip or coplanar waveguide lines impede the use of standard patch or slot antennas for a large number of elements in a phased array format. Traditionally, this problem has been solved by using silicon lenses. However, if an array of such highly directive antennas is to be used for imaging applications, the fabrication of many closely spaced lenses becomes a problem. Moreover, planar antennas are usually fed by microstrip or coplanar waveguides while the mixer or the detector elements (usually Schottky diodes) are coupled in a waveguide environment. The coupling between the antenna and the detector/ mixer can be a fabrication challenge in an imaging array at submillimeter wavelengths. Antennas excited by a waveguide (TE10) mode makes use of dielectric superlayers to increase the directivity. These antennas create a kind of Fabry- Perot cavity between the ground plane and the first layer of dielectric. In reality, the antenna operates as a leaky wave mode where a leaky wave pole propagates along the cavity while it radiates. Thanks to this pole, the directivity of a small antenna is considerably enhanced. The antenna consists of a waveguide feed, which can be coupled to a mixer or detector such as a Schottky diode via a standard probe design. The waveguide is loaded with a double-slot iris to perform an impedance match and to suppress undesired modes that can propagate on the cavity. On top of the slot there is an air cavity and on top, a small portion of a hemispherical lens. The fractional bandwidth of such antennas is around 10 percent, which is good enough for heterodyne imaging applications.The new geometry makes use of a silicon lens instead of dielectric quarter wavelength substrates. This design presents several advantages when used in the submillimeter

  3. Detection of Circular Polarization from Sagittarius A* at Submillimeter Wavelengths

    Science.gov (United States)

    Munoz, Diego; Marrone, D.; Moran, J.

    2009-05-01

    We report the detection of circularly polarized (CP) emission from the compact radio source Sagittarius A* at a level of 1.5% at a frequency of 235 GHz (1.4 mm). Sgr A* is associated with the supermassive black hole (SMBH) in the Galactic Center. The observations, taken with the Submillimeter Array (SMA) on 03/31/2007, also show a linearly polarized (LP) component of 7%. The snr of our detection of CP is about 14. Before our measurements, CP had only been detected at frequencies between 1.4 and 15 GHz (21 and 2 cm) at levels Faraday rotation in the stationary screen (constant RM)acts on a time variable background source. A cold, optically thin plasma screen cannot be responsible for both a constant RM and Faraday conversion from LP to CP, therefore the observed amounts of CP are likely to be originated close to the central source. Sgr A* shows a flat-to-inverted radio spectrum and a submillimeter excess referred to as the "submillimeter bump". This excess it thought to come from the closest regions to the SMBH. In such a scenario, millimeter wavelength data is associated with regions in which the material is likely to be relativistic and the magnetic field ordered. We have carried out polarized radiative transfer calculations exploring different combinations of ordered and stochastic magnetic fields looking for a favored scenario that can explain the apparent constant increase of CP with frequency as well as the sudden jump in LP between 40 and 80 GHz.

  4. Josephson frequency meter for millimeter and submillimeter wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Anischenko, S.E.; Larkin, S.Y.; Chaikovsky, V.I. [State Research Center, Kiev (Ukraine)] [and others

    1994-12-31

    Frequency measurements of electromagnetic oscillations of millimeter and submillimeter wavebands with frequency growth due to a number of reasons become more and more difficult. First, these frequencies are considered to be cutoff for semiconductor converting devices and one has to use optical measurement methods instead of traditional ones with frequency transfer. Second, resonance measurement methods are characterized by using relatively narrow bands and optical ones are limited in frequency and time resolution due to the limited range and velocity of movement of their mechanical elements as well as the efficiency of these optical techniques decreases with the increase of wavelength due to diffraction losses. That requires the apriori information on the radiation frequency band of the source involved. Method of measuring frequency of harmonic microwave signals in millimeter and submillimeter wavebands based on the ac Josephson effect in superconducting contacts is devoid of all the above drawbacks. This approach offers a number of major advantages over the more traditional measurement methods, that is the one based on frequency conversion, resonance and interferrometric techniques. It can be characterized by high potential accuracy, wide range of frequencies measured, prompt measurement and the opportunity to obtain panoramic display of the results as well as full automation of the measuring process.

  5. High-Sensitivity AGN Polarimetry at Sub-Millimeter Wavelengths

    Directory of Open Access Journals (Sweden)

    Ivan Martí-Vidal

    2017-10-01

    Full Text Available The innermost regions of radio loud Active Galactic Nuclei (AGN jets are heavily affected by synchrotron self-absorption, due to the strong magnetic fields and high particle densities in these extreme zones. The only way to overcome this absorption is to observe at sub-millimeter wavelengths, although polarimetric observations at such frequencies have so far been limited by sensitivity and calibration accuracy. However, new generation instruments such as the Atacama Large mm/sub-mm Array (ALMA overcome these limitations and are starting to deliver revolutionary results in the observational studies of AGN polarimetry. Here we present an overview of our state-of-the-art interferometric mm/sub-mm polarization observations of AGN jets with ALMA (in particular, the gravitationally-lensed sources PKS 1830−211 and B0218+359, which allow us to probe the magneto-ionic conditions at the regions closest to the central black holes.

  6. A Black Hole Mass-Variability Timescale Correlation at Submillimeter Wavelengths

    NARCIS (Netherlands)

    Bower, G.C.; Dexter, J.; Markoff, S.; Gurwell, M.A.; Rao, R.; McHardy, I.

    2015-01-01

    We analyze the light curves of 413 radio sources at submillimeter wavelengths using data from the Submillimeter Array calibrator database. The database includes more than 20,000 observations at 1.3 and 0.8 mm that span 13 years. We model the light curves as a damped random walk and determine a

  7. The SCUBA-2 Cosmology Legacy Survey: Multi-wavelength Properties of ALMA-identified Submillimeter Galaxies in UKIDSS UDS

    NARCIS (Netherlands)

    Simpson, J. M.; Smail, Ian; Swinbank, A. M.; Ivison, R. J.; Dunlop, J. S.; Geach, J. E.; Almaini, O.; Arumugam, V.; Bremer, M. N.; Chen, Chian-Chou; Conselice, C.; Coppin, K. E. K.; Farrah, D.; Ibar, E.; Hartley, W. G.; Ma, C. J.; Michałowski, M. J.; Scott, D.; Spaans, M.; Thomson, A. P.; van der Werf, P. P.

    2017-01-01

    We present a multi-wavelength analysis of 52 submillimeter galaxies (SMGs), identified using ALMA 870 μm continuum imaging in a pilot program to precisely locate bright SCUBA-2-selected submillimeter sources in the UKIDSS Ultra Deep Survey (UDS) field. Using the available deep (especially

  8. Laboratory and observational studies of transient molecules at microwave and millimeter/submillimeter wavelengths

    Science.gov (United States)

    Zack, Lindsay Nicole

    In this dissertation, techniques of high-resolution rotational spectroscopy have been used to measure the spectra of molecules in both laboratory and astronomical settings. In the laboratory, small metal-bearing molecules containing zinc, iron, nickel, titanium, yttrium, and scandium have been studied at microwave and millimeter/submillimeter wavelengths in order to determine their rotational, fine, and hyperfine constants. These molecules were synthesized in situ in direct-absorption and Fourier-transform microwave spectrometers using Broida-type ovens and laser ablation methods. From the spectroscopic parameters, information about fundamental physical properties and electronic character could be obtained. Radio telescopes were used to measure the spectra of molecules in different interstellar environments. A new molecule, FeCN, was detected toward the circumstellar envelope of the carbon-rich asymtotic giant branch star, IRC+10216, marking the first iron-bearing molecule detected in the interstellar medium. The telescopes were also used to conduct a study of the evolved planetary nebula, NGC 7293, or the Helix Nebula. In the Helix, CO, HCO+, and H2CO were observed at several positions offset from the central star to obtain densities and kinetic temperatures throughout the Helix. A map of the HCO+ J = 1→ 0 transition was also constructed, showing that HCO+ is widespread throughout the Helix, instead of being photodissociated and destroyed, as theoretical models of planetary nebulae predict.

  9. Signal to Noise Ratio Maximization in Quiet Zone Acquisitions for Range Assessment at Sub-millimeter Wavelengths

    Directory of Open Access Journals (Sweden)

    A. Muñoz-Acevedo

    2012-06-01

    Full Text Available This paper proposes a quiet zone probing approach which deals with low dynamic range quiet zone acquisitions. Lack of dynamic range is a feature of millimeter and sub-millimeter wavelength technologies. It is consequence of the gradually smaller power generated by the instrumentation, that follows a f^α law with frequency, being α≥1 variable depending on the signal source’s technology. The proposed approach is based on an optimal data reduction scenario which redounds in a maximum signal to noise ratio increase for the signal pattern, with minimum information losses. After theoretical formulation, practical applications of the technique are proposed.

  10. Study of optical output couplers for submillimeter wavelength backward-wave oscillators (BWO's)

    Science.gov (United States)

    Cook, Jerry D.; Stankiewicz, Norbert; Podany, Mark

    1989-01-01

    Several scaled experiments of optical output couplers for submillimeter backward-wave oscillators (BWOs). Various designs of planar antennas (Vivaldi horns) lens-feed systems (hyperhemispherical lens) were constructed and tested between 20 and 100 GHz using a spectrum analyzer. The lens system was also tested at 337 GHz using a CO2 pumped FIR laser. It is found that Vivaldi horns have unsatisfactory resonances, perhaps because the horns studied were relatively short. Several techniques to maximize and flatten the frequency response of these horns are presented. The results suggest that alternate coupling schemes are superior to Vivaldi horns.

  11. The ALMA Phasing System: A Beamforming Capability for Ultra-high-resolution Science at (Sub)Millimeter Wavelengths

    Science.gov (United States)

    Matthews, L. D.; Crew, G. B.; Doeleman, S. S.; Lacasse, R.; Saez, A. F.; Alef, W.; Akiyama, K.; Amestica, R.; Anderson, J. M.; Barkats, D. A.; Baudry, A.; Broguière, D.; Escoffier, R.; Fish, V. L.; Greenberg, J.; Hecht, M. H.; Hiriart, R.; Hirota, A.; Honma, M.; Ho, P. T. P.; Impellizzeri, C. M. V.; Inoue, M.; Kohno, Y.; Lopez, B.; Martí-Vidal, I.; Messias, H.; Meyer-Zhao, Z.; Mora-Klein, M.; Nagar, N. M.; Nishioka, H.; Oyama, T.; Pankratius, V.; Perez, J.; Phillips, N.; Pradel, N.; Rottmann, H.; Roy, A. L.; Ruszczyk, C. A.; Shillue, B.; Suzuki, S.; Treacy, R.

    2018-01-01

    The Atacama Millimeter/submillimeter Array (ALMA) Phasing Project (APP) has developed and deployed the hardware and software necessary to coherently sum the signals of individual ALMA antennas and record the aggregate sum in Very Long Baseline Interferometry (VLBI) Data Exchange Format. These beamforming capabilities allow the ALMA array to collectively function as the equivalent of a single large aperture and participate in global VLBI arrays. The inclusion of phased ALMA in current VLBI networks operating at (sub)millimeter wavelengths provides an order of magnitude improvement in sensitivity, as well as enhancements in u–v coverage and north–south angular resolution. The availability of a phased ALMA enables a wide range of new ultra-high angular resolution science applications, including the resolution of supermassive black holes on event horizon scales and studies of the launch and collimation of astrophysical jets. It also provides a high-sensitivity aperture that may be used for investigations such as pulsar searches at high frequencies. This paper provides an overview of the ALMA Phasing System design, implementation, and performance characteristics.

  12. Metal-mesh achromatic half-wave plate for use at submillimeter wavelengths.

    Science.gov (United States)

    Pisano, Giampaolo; Savini, Giorgio; Ade, Peter A R; Haynes, Vic

    2008-11-20

    A metal-mesh achromatic half-wave plate (HWP) has been designed, manufactured, and tested for potential use in millimeter and submillimeter astronomical instruments. The prototype device presented here is based on a 12-grid Shatrow [IEEE Trans. Antennas Propag. 43, 109 (1995)] recipe to operate over the frequency range of 120-180 GHz. Transmission line modeling and finite-element analysis [Ansoft HFSS website: http://www.ansoft.com/hfss/] were used to optimize the design geometrical parameters in terms of the device transmission, reflection, absorption, phase-shift, and cross-polarization as a function of frequency. The resulting prototype device was constructed and characterized using incoherent radiation from a polarizing Fourier transform spectrometer to explore its frequency and polarization behavior. These measurements are shown to be in excellent agreement with the models. Lists of the achieved HWP performance characteristics are reported.

  13. The multi-wavelength properties of faint submillimeter galaxies at 450 and 850um

    Science.gov (United States)

    Zavala, Jorge; Aretxaga, Itziar; Hughes, David; Dunlop, James; Michalowski, Michal; SCUBA-2 Cosmology Legacy Survey

    2017-01-01

    We present a multi-wavelength analysis for galaxies selected at 450 and 850um from the deepest SCUBA-2 observations in the EGS field. The median redshifts for the 450 and 850um samples are z~1.6 and z~2.2, respectively. However, the two populations have similar IR luminosities, SFR, and stellar masses, with mean values of ~1.5x10^12 L_sun, 150 M_sun/yr, and 9x10^10 M_sun, respectively. We find that most of our sources (>80%) lie in the high-mass end of the `main sequence' of star-forming galaxies. Exploring the IRX-beta relation we find that the most luminous galaxies are consistent with the Muerer law, while the less luminous galaxies are in better agreement with the SMC relation. Using the results of a two-dimensinal modelling of the HST H_160-band, we derive a median Sersic index of n=1.4 and a median half-light radius of ~4.8kpc for the whole sample. Based on a visual-like classification in the same band we find that the dominant component for most of the galaxies at all redshift is a disk, although there is a transition from irregular disks to disks with a spheroidal component from high to low redshift, which supports the scenario of SMGs as progenitors of present-day massive elliptical galaxies.

  14. Acoustic levitation of an object larger than the acoustic wavelength.

    Science.gov (United States)

    Andrade, Marco A B; Okina, Fábio T A; Bernassau, Anne L; Adamowski, Julio C

    2017-06-01

    Levitation and manipulation of objects by sound waves have a wide range of applications in chemistry, biology, material sciences, and engineering. However, the current acoustic levitation techniques are mainly restricted to particles that are much smaller than the acoustic wavelength. In this work, it is shown that acoustic standing waves can be employed to stably levitate an object much larger than the acoustic wavelength in air. The levitation of a large slightly curved object weighting 2.3 g is demonstrated by using a device formed by two 25 kHz ultrasonic Langevin transducers connected to an aluminum plate. The sound wave emitted by the device provides a vertical acoustic radiation force to counteract gravity and a lateral restoring force that ensure horizontal stability to the levitated object. In order to understand the levitation stability, a numerical model based on the finite element method is used to determine the acoustic radiation force that acts on the object.

  15. Submillimeter Continuum Observations of Comets

    Science.gov (United States)

    Jewitt, David

    1998-01-01

    The aim of this proposal was to study the submillimeter continuum emission from comets. The study was based mainly on the exploitation of the world's leading submillimeter telescope, the JCMT (James Clerk Maxwell Telescope) on Mauna Kea. Submillimeter wavelengths provide a unique view of cometary physics for one main reason. The cometary size distribution is such that the scattering cross-section is dominated by small dust grains, while the mass is dominated by the largest particles. Submillimeter continuum radiation samples cometary particles much larger than those sampled by more common observations at shorter (optical and infrared) wavelengths and therefore provides a nearly direct measure of the cometary dust mass.

  16. A system for measuring complex dielectric properties of thin films at submillimeter wavelengths using an open hemispherical cavity and a vector network analyzer

    Science.gov (United States)

    Rahman, Rezwanur; Taylor, P. C.; Scales, John A.

    2013-08-01

    Quasi-optical (QO) methods of dielectric spectroscopy are well established in the millimeter and submillimeter frequency bands. These methods exploit standing wave structure in the sample produced by a transmitted Gaussian beam to achieve accurate, low-noise measurement of the complex permittivity of the sample [e.g., J. A. Scales and M. Batzle, Appl. Phys. Lett. 88, 062906 (2006);, 10.1063/1.2172403 R. N. Clarke and C. B. Rosenberg, J. Phys. E 15, 9 (1982);, 10.1088/0022-3735/15/1/002 T. M. Hirovnen, P. Vainikainen, A. Lozowski, and A. V. Raisanen, IEEE Trans. Instrum. Meas. 45, 780 (1996)], 10.1109/19.516996. In effect the sample itself becomes a low-Q cavity. On the other hand, for optically thin samples (films of thickness much less than a wavelength) or extremely low loss samples (loss tangents below 10-5) the QO approach tends to break down due to loss of signal. In such a case it is useful to put the sample in a high-Q cavity and measure the perturbation of the cavity modes. Provided that the average mode frequency divided by the shift in mode frequency is less than the Q (quality factor) of the mode, then the perturbation should be resolvable. Cavity perturbation techniques are not new, but there are technological difficulties in working in the millimeter/submillimeter wave region. In this paper we will show applications of cavity perturbation to the dielectric characterization of semi-conductor thin films of the type used in the manufacture of photovoltaics in the 100 and 350 GHz range. We measured the complex optical constants of hot-wire chemical deposition grown 1-μm thick amorphous silicon (a-Si:H) film on borosilicate glass substrate. The real part of the refractive index and dielectric constant of the glass-substrate varies from frequency-independent to linearly frequency-dependent. We also see power-law behavior of the frequency-dependent optical conductivity from 316 GHz (9.48 cm-1) down to 104 GHz (3.12 cm-1).

  17. A quasioptical steering system for the CCAT/XSPEC submillimeter multi-object spectrometer

    OpenAIRE

    Chapman, S.C.; Tikhomirov, A.; Bradford, C.M.; Hailey-Dunsheath, S.

    2014-01-01

    A two arm, opto-mechanical positioner mechanism is presented in this proceedings as a candidate steering system for the millimeter-wave XSPEC spectrograph. The design is well matched to the expected target density on the sky, and meeting all requirements of the Cerro Chajnantor Atacama Telescope (CCAT), site environmental conditions (e.g., operating temperature and power dissipation), and the positioning requirements themselves for acquiring and tracking astronomical objects whose light is fe...

  18. A quasioptical steering system for the CCAT/XSPEC submillimeter multi-object spectrometer

    Science.gov (United States)

    Chapman, S. C.; Tikhomirov, A.; Bradford, C. M.; Hailey-Dunsheath, S.

    2014-07-01

    A two arm, opto-mechanical positioner mechanism is presented in this proceedings as a candidate steering system for the millimeter-wave XSPEC spectrograph. The design is well matched to the expected target density on the sky, and meeting all requirements of the Cerro Chajnantor Atacama Telescope (CCAT), site environmental conditions (e.g., operating temperature and power dissipation), and the positioning requirements themselves for acquiring and tracking astronomical objects whose light is fed into the XSPEC spectrograph units. The prototype design has been fabricated and tested for basic operations.

  19. Objective identification of informative wavelength regions in galaxy spectra

    Energy Technology Data Exchange (ETDEWEB)

    Yip, Ching-Wa; Szalay, Alexander S.; Budavári, Tamás; Wyse, Rosemary F. G. [Department of Physics and Astronomy, The Johns Hopkins University, 3701 San Martin Drive, Baltimore, MD 21218 (United States); Mahoney, Michael W. [Department of Mathematics, Stanford University, Stanford, CA 94305 (United States); Csabai, István; Dobos, Laszlo, E-mail: cwyip@pha.jhu.edu, E-mail: szalay@jhu.edu, E-mail: mmahoney@cs.stanford.edu [Department of Physics of Complex Systems, Eötvös Loránd University, H-1117 Budapest (Hungary)

    2014-05-01

    Understanding the diversity in spectra is the key to determining the physical parameters of galaxies. The optical spectra of galaxies are highly convoluted with continuum and lines that are potentially sensitive to different physical parameters. Defining the wavelength regions of interest is therefore an important question. In this work, we identify informative wavelength regions in a single-burst stellar population model using the CUR Matrix Decomposition. Simulating the Lick/IDS spectrograph configuration, we recover the widely used D {sub n}(4000), Hβ, and Hδ {sub A} to be most informative. Simulating the Sloan Digital Sky Survey spectrograph configuration with a wavelength range 3450-8350 Å and a model-limited spectral resolution of 3 Å, the most informative regions are: first region—the 4000 Å break and the Hδ line; second region—the Fe-like indices; third region—the Hβ line; and fourth region—the G band and the Hγ line. A principal component analysis on the first region shows that the first eigenspectrum tells primarily the stellar age, the second eigenspectrum is related to the age-metallicity degeneracy, and the third eigenspectrum shows an anti-correlation between the strengths of the Balmer and the Ca K and H absorptions. The regions can be used to determine the stellar age and metallicity in early-type galaxies that have solar abundance ratios, no dust, and a single-burst star formation history. The region identification method can be applied to any set of spectra of the user's interest, so that we eliminate the need for a common, fixed-resolution index system. We discuss future directions in extending the current analysis to late-type galaxies. ASCII formatted tables of the regional eigenspectra are available.

  20. Filters for Submillimeter Electromagnetic Waves

    Science.gov (United States)

    Berdahl, C. M.

    1986-01-01

    New manufacturing process produces filters strong, yet have small, precise dimensions and smooth surface finish essential for dichroic filtering at submillimeter wavelengths. Many filters, each one essentially wafer containing fine metal grid made at same time. Stacked square wires plated, fused, and etched to form arrays of holes. Grid of nickel and tin held in brass ring. Wall thickness, thickness of filter (hole depth) and lateral hole dimensions all depend upon operating frequency and filter characteristics.

  1. Active Millimeter and Submillimeter Sensing Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The workshop will have three main objectives. The first will be to inventory the signatures and measurements that are desirable to make using submillimeter active...

  2. Advanced Amplifier Based Receiver Front Ends for Submillimeter-Wave-Sounders Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop high electron mobility transistor (HEMT) amplifier based heterodyne radiometers to provide high sensitivity at millimeter and submillimeter wavelengths with...

  3. Submillimeter Array reveals molecular complexity of dying stars

    Science.gov (United States)

    Tomasz

    2018-01-01

    The unique capabilities of the Submillimeter Array (SMA) have allowed unprecedented studies of cool evolved stars at submillimeter wavelengths. In particular, the SMA now offers the possibility to image multiple molecular transitions at once, owing to the 32-GHz wide instantaneous bandwidth of SWARM, the SMA’s new correlator. Molecular gas located far and very close to the photosphere of an asymptotic-giant branch (AGB) star, a red supergiant, or a pre-planetary nebula can now be examined in transitions observed simultaneously from a wide range of energy levels. This allows a very detailed quantitative investigation of physical and chemical conditions around these variable objects. Several imaging line surveys have been obtained with the SMA to reveal the beautiful complexity of these evolved systems. The surveys resulted in first submillimeter-wave identifications of molecules of prime astrophysical interest, e.g. of TiO, TiO2, and of rotational transitions at excited vibrational states of CO. An overview of recent SMA observations of cool evolved stars will be given with an emphasize on the interferometric line surveys. We will demonstrate their importance in unraveling the mass-loss phenomena, propagation of shocks in the circumstellar medium, and production of dust at elevated temperatures. The SMA studies of these molecular factories have a direct impact on our understanding of the chemical evolution of the Galaxy and stellar evolution at low and high masses.

  4. Effect of object size and acoustic wavelength on pulsed ultrasound modulated fluorescence signals

    Science.gov (United States)

    Huynh, Nam T.; Ruan, Haowen; He, Diwei; Hayes-Gill, Barrie R.; Morgan, Stephen P.

    2012-07-01

    Detection of ultrasound (US)-modulated fluorescence in turbid media is a challenge because of the low level of fluorescent light and the weak modulation of incoherent light. A very limited number of theoretical and experimental investigations have been performed, and this is, to our knowledge, the first demonstration of pulsed US-modulated fluorescence tomography. Experimental results show that the detected signal depends on the acoustic frequency and the fluorescent target's size along the ultrasonic propagation axis. The modulation depth of the detected signal is greatest when the length of the object along the acoustic axis is an odd number of half wavelengths and is weakest when the object is an integer multiple of an acoustic wavelength. Images of a fluorescent tube embedded within a 22- by 13- by 30 mm scattering gel phantom (μs~15 cm-1, g=0.93) with 1-, 1.5-, and 2 MHz frequency US are presented. The modulation depth of the detected signal changes by a factor of 5 depending on the relative size of the object and the frequency. The approach is also verified by some simple experiments in a nonscattering gel and using a theoretical model.

  5. The thermal emission of Centaurs and trans-Neptunian objects at millimeter wavelengths from ALMA observations

    Science.gov (United States)

    Lellouch, E.; Moreno, R.; Müller, T.; Fornasier, S.; Santos-Sanz, P.; Moullet, A.; Gurwell, M.; Stansberry, J.; Leiva, R.; Sicardy, B.; Butler, B.; Boissier, J.

    2017-12-01

    The sensitivity of ALMA makes it possible to detect thermal mm/submm emission from small and/or distant solar system bodies at the sub-mJy level. While the measured fluxes are primarily sensitive to the objects' diameters, deriving precise sizes is somewhat hampered by the uncertain effective emissivity at these wavelengths. Following recent work presenting ALMA data for four trans-Neptunian objects (TNOs) with satellites, we report on ALMA 233 GHz (1.29 mm) flux measurements of four Centaurs (2002 GZ32, Bienor, Chiron, Chariklo) and two other TNOs (Huya and Makemake), sampling a range of sizes, albedos, and compositions. These thermal fluxes are combined with previously published fluxes in the mid/far infrared in order to derive their relative emissivity at radio (mm/submm) wavelengths, using the Near Earth Asteroid Standard Model (NEATM) and thermophysical models. We reassess earlier thermal measurements of these and other objects - including Pluto/Charon and Varuna - exploring, in particular, effects due to non-spherical shape and varying apparent pole orientation whenever information is available, and show that these effects can be key for reconciling previous diameter determinations and correctly estimating the spectral emissivities. We also evaluate the possible contribution to thermal fluxes of established (Chariklo) or claimed (Chiron) ring systems. For Chariklo, the rings do not impact the diameter determinations by more than 5%; for Chiron, invoking a ring system does not help in improving the consistency between the numerous past size measurements. As a general conclusion, all the objects, except Makemake, have radio emissivities significantly lower than unity. Although the emissivity values show diversity, we do not find any significant trend with physical parameters such as diameter, composition, beaming factor, albedo, or color, but we suggest that the emissivity could be correlated with grain size. The mean relative radio emissivity is found to be 0

  6. A submillimeter VLBI array

    Energy Technology Data Exchange (ETDEWEB)

    Weintroub, Jonathan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA (United States)], E-mail: jweintroub@cfa.harvard.edu

    2008-10-15

    A VLBI array operating at {lambda} 1.3 mm and 0.8 mm is being designed using existing submillimeter telescopes as ad-hoc stations. Initial three station {lambda} = 1.3 mm observations of SgrA* and other AGN have produced remarkable results, which are reported by Doeleman elsewhere in this proceedings. Future observations are planned with an enhanced array which has longer baselines, more stations, and greater sensitivity. At {lambda} = 0.8 mm and on the long baselines, the array will have about a 20 {mu}as angular resolution which equals the diameter of the event horizon of the massive black hole in SgrA*. Candidate single dish facilities include the Arizona Radio Observatory Submillimeter Telescope (SMT) in Arizona, the Caltech Submillimeter Observatory (CSO) and the James Clerk Maxwell telescope (JCMT) in Hawaii, the Large Millimeter Telescope (LMT) in Mexico, ASTE and APEX in Chile, and the IRAM 30 m in Spain; interferometers include the Submillimeter Array (SMA) in Hawaii, the Combined Array for Research in Millimeter-wave Astronomy (CARMA) in California, IRAM PdB Interferometer in France, and the Atacama Large Millimeter Array (ALMA) in Chile. I will discuss the techniques we have developed for phasing interferometric arrays to act as single VLBI station. A strategy for detection of short (10s) time-scale source variability using VLBI closure phase will be described.

  7. Submillimeter solar images from the JCMT

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, G.; Lindsey, C.

    1992-01-01

    We present nearly full-disk, diffraction-limited solar images made at 350 and 850 [mu]m and at 1.3 mm from the 15 m James Clerk Maxwell Telescope on Mauna Kea. These wavelengths sample the thermal structure of the solar chromosphere at altitude from 500 to about 1500 km, providing a height-dependent diagnostic of the atmosphere. Filament channels and neutral lines are apparent in the submillimeter images, although filaments themselves are not clearly visible. The submillimeter images show plage approximately 20% brigher than the surrounding quiet Sun, while sunspot intensities are comparable to the quiet Sun. Circumfacules,' dark are similar to those seen in Ca 8542; comparison with Ca H and K may give estimates of the temperature and filing factor of the hot gas present in these probably bifurcated regions.

  8. Lightweight Thermally Stable Multi-Meter Aperture Submillimeter Reflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Phase II effort will be an affordable demonstrated full-scale design for a thermally stable multi-meter submillimeter reflector. The Phase I...

  9. An alma survey of sub-millimeter galaxies in the extended Chandra deep field south: Sub-millimeter properties of color-selected galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Decarli, R.; Walter, F.; Hodge, J. A.; Rix, H.-W.; Schinnerer, E. [Max-Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Smail, I.; Swinbank, A. M.; Karim, A.; Simpson, J. M. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Chapman, S. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Coppin, K. E. K. [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Cox, P. [IRAM, 300 rue de la piscine, F-38406 Saint-Martin d' Hères (France); Dannerbauer, H. [Universität Wien, Institut für Astrophysik, Türenschanzstrasse 17, A-1180 Wien (Austria); Greve, T. R. [University College London, Department of Physics and Astronomy, Gower Street, London WC1E 6BT (United Kingdom); Ivison, R. [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Knudsen, K. K.; Lindroos, L. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, Onsala SE-439 92 (Sweden); Van der Werf, P. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Weiß, A., E-mail: decarli@mpia.de [Max-Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2014-01-10

    We study the sub-millimeter properties of color-selected galaxies via a stacking analysis applied for the first time to interferometric data at sub-millimeter wavelengths. We base our study on 344 GHz ALMA continuum observations of ∼20''-wide fields centered on 86 sub-millimeter sources detected in the LABOCA Extended Chandra Deep Field South (ECDFS) Sub-millimeter Survey. We select various classes of galaxies (K-selected, star-forming sBzK galaxies, extremely red objects, and distant red galaxies) according to their optical/near-infrared fluxes. We find clear, >10σ detections in the stacked images of all these galaxy classes. We include in our stacking analysis Herschel/SPIRE data to constrain the dust spectral energy distribution of these galaxies. We find that their dust emission is well described by a modified blackbody with T {sub dust} ≈ 30 K and β = 1.6 and infrared luminosities of (5-11) × 10{sup 11} L {sub ☉} or implied star formation rates of 75-140 M {sub ☉} yr{sup –1}. We compare our results with those of previous studies based on single-dish observations at 870 μm and find that our flux densities are a factor 2-3 higher than previous estimates. The discrepancy is observed also after removing sources individually detected in ALESS maps. We report a similar discrepancy by repeating our analysis on 1.4 GHz observations of the whole ECDFS. Hence, we find tentative evidence that galaxies that are associated in projected and redshift space with sub-mm bright sources are brighter than the average population. Finally, we put our findings in the context of the cosmic star formation rate density as a function of redshift.

  10. HERTZ, A Submillimeter Polarimeter

    Science.gov (United States)

    Schleuning, D. A.; Dowell, C. D.; Hildebrand, R. H.; Platt, S. R.; Novak, G.

    1997-03-01

    We describe a 32 pixel polarimeter, Hertz, for use at the Caltech Submillimeter Observatory. We present polarization maps of the Orion molecular cloud (OMC-1) at 350 \\mum (46 detections) and 450 \\mum (19 detections) with 3\\sigma or better statistical significance. The 350 \\mum polarization ranges from 1.4 to 6.8% with a median value of 3.3%. The position angles are fairly uniform across the souce at an angle of \\sim30 degrees (east of north). We describe the design and performance characteristics of the polarimeter and discuss systematic effects due to telescope and instrumental polarization, atmospheric fluctuations, and reference beam flux. (SECTION: Astronomical Instrumentation)

  11. Probing Galaxy Formation and Submillimeter Surveys

    Science.gov (United States)

    Dwek, Eli; Arendt, Richard G.; Benford, Dominic J.; Moseley, Harvey S.; Shafer, Richard A.; Staguhn, Johannes G.; Fisher, Richard R. (Technical Monitor)

    2002-01-01

    Multiwavelength observations of galaxies have revealed that a significant fraction of the their stellar or accretion luminosity is absorbed and reradiated by dust at far-infrared (FIR) and submillimeter (submm) wavelengths. Submillimeter (850 micron) surveys conducted by the SCUBA instrument on the JCMT have detected a population of high redshift (z approximately equal to 1-4) ultraluminous infrared galaxies, that dominate the luminosity densities at those redshifts. Their cumulative contribution to the cosmic infrared background (CIB) detected by the COBE satellite is comparable to the observations, suggesting that at 850 microns the CIB is resolved into its constituent sources. This suggests that the early universe was much more dust enshrouded than the present one. FIR and submm surveys can therefore address fundamental questions regarding the early processes of galaxy formation and their evolution in number and luminosity over cosmic history. The scientific information that can be obtained from such surveys depend on a number of parameters, the most important of which are the diameter of the telescope and the wavelengths of the survey. We summarize the effect of these parameters on the scientific return from such surveys.

  12. Long-Wavelength Excesses of FU Orionis Objects: Flared Outer Disks or Infalling Envelopes?

    Science.gov (United States)

    Zhu, Zhaohuan; Hartmann, Lee; Calvet, Nuria; Hernandez, Jesus; Tannirkulam, Ajay-Kumar; D'Alessio, Paola

    2008-09-01

    The mid- to far-infrared emission of the outbursting FU Orionis objects has been attributed either to a flared outer disk or to an infalling envelope. We revisit this issue using detailed radiative transfer calculations to model the recent, high signal-to-noise ratio data from the IRS instrument on the Spitzer Space Telescope. In the case of FU Ori, we find that a physically plausible flared disk irradiated by the central accretion disk matches the observations. Building on our previous work, our accretion disk model with outer disk irradiation by the inner disk reproduces the spectral energy distribution between ~4000 Å and ~40 μm. Our model is consistent with near-infrared interferometry, but there are some inconsistencies with mid-infrared interferometric results. Including the outer disk allows us to refine our estimate of the outer radius of the outbursting, high mass accretion rate disk in FU Ori as ~0.5 AU, which is a crucial parameter in assessing theories of the FU Orionis phenomenon. We are able to place an upper limit on the mass infall rate of any remnant envelope infall rate to ~7 × 10-7 M⊙ yr -1 assuming a centrifugal radius of 200 AU. The FUor BBW 76 is also well modeled by a 0.6 AU inner disk and a flared outer disk. However, V1515 Cyg requires an envelope with an outflow cavity to adequately reproduce the IRS spectrum. In contrast with the suggestion by Green et al., we do not require a flattened envelope to match the observations; the inferred cavity shape is qualitatively consistent with typical protostellar envelopes. This variety of dusty structures suggests that the FU Orionis phase can be present at either early or late stages of protostellar evolution.

  13. Comparing Submillimeter Polarized Emission with Near-infrared Polarization of Background Stars for the Vela C Molecular Cloud

    Science.gov (United States)

    Santos, Fabio P.; Ade, Peter A. R.; Angilè, Francesco E.; Ashton, Peter; Benton, Steven J.; Devlin, Mark J.; Dober, Bradley; Fissel, Laura M.; Fukui, Yasuo; Galitzki, Nicholas; Gandilo, Natalie N.; Klein, Jeffrey; Korotkov, Andrei L.; Li, Zhi-Yun; Martin, Peter G.; Matthews, Tristan G.; Moncelsi, Lorenzo; Nakamura, Fumitaka; Netterfield, Calvin B.; Novak, Giles; Pascale, Enzo; Poidevin, Frédérick; Savini, Giorgio; Scott, Douglas; Shariff, Jamil A.; Diego Soler, Juan; Thomas, Nicholas E.; Tucker, Carole E.; Tucker, Gregory S.; Ward-Thompson, Derek

    2017-03-01

    We present a large-scale combination of near-infrared (near-IR) interstellar polarization data from background starlight with polarized emission data at submillimeter wavelengths for the Vela C molecular cloud. The near-IR data consist of more than 6700 detections probing a range of visual extinctions between 2 and 20 {mag} in and around the cloud. The submillimeter data were collected in Antarctica by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry. This is the first direct combination of near-IR and submillimeter polarization data for a molecular cloud aimed at measuring the “polarization efficiency ratio” ({R}{eff}), a quantity that is expected to depend only on grain-intrinsic physical properties. It is defined as {p}500/({p}I/{τ }V), where p 500 and p I are polarization fractions at 500 μ {{m}} and the I band, respectively, and {τ }V is the optical depth. To ensure that the same column density of material is producing both polarization from emission and from extinction, we conducted a careful selection of near-background stars using 2MASS, Herschel, and Planck data. This selection excludes objects contaminated by the Galactic diffuse background material as well as objects located in the foreground. Accounting for statistical and systematic uncertainties, we estimate an average {R}{eff} value of 2.4 ± 0.8, which can be used to test the predictions of dust grain models designed for molecular clouds when such predictions become available. The ratio {R}{eff} appears to be relatively flat as a function of the cloud depth for the range of visual extinctions probed.

  14. Infrared/submillimeter optical properties data base

    Science.gov (United States)

    Alley, Phillip W.

    1989-01-01

    The general goal was to build a data base containing optical properties, such as reflectance, transmittance, refractive index, in the far infrared to submillimeter wavelength region. This data base would be limited to selected crystalline materials and temperature between 300 and 2 K. The selected materials were: lithium, lead, and strontium; the bromides of potassium and thallium; the carbides of silicone and tungsten; and the materials of KRS5, KRS6, diamond, and sapphire. Last summer, barium fluoride was selected as prototype material for building the data base. This summer the literature search, preparation of the data for barium fluoride was completed. In addition the literature search for data related to the compounds mentioned was completed. The current status is that barium fluoride is in a form suitable for a NASA internal publication. The papers containing the data on the other materials were xeroxed and they are ready to be reduced. On the reverse side, the top figure is a sample combination of data for the index of refraction at 300 K. The lower figure shows the transmittance vs wavelength at 300 and 80 K. These figures are a sample of many which were developed. Since barium fluoride was studied more than most of the materials listed above, it is clear that additional measurements should be made to fill in the gaps present on both temperature and wavelength data.

  15. Characterization of microscope objective lenses from 1,400 to 1,650 nm to evaluate performance for long-wavelength nonlinear microscopy applications.

    Science.gov (United States)

    Keatings, Stefanie Renaud; Zhang, Wei; McConnell, Gail

    2008-07-01

    We have demonstrated a simple method for characterization of objective lens performance at longer wavelengths for 3PLSM and THG imaging. We investigated a range of air and oil-immersion objective lenses across a wavelength range of 1,400-1,650 nm using a synchronously pumped optical parametric oscillator laser source. In the first instance, we investigated the percentage light transmission across this spectral range. Second, we used a simple second harmonic autocorrelation pulse measurement technique to study the dispersion properties of these lenses at the range of input wavelengths. For the objective lenses investigated, we observed pulse broadening on the order of around 4%-7% for air immersion lenses and 9%-12% for oil immersion lenses. Even for the greater dispersion incurred by the application of the oil immersion lenses, these objectives are suitable for longer wavelength application in conjunction with a suitable light source. The same techniques could easily be applied for a larger range of objective lenses and adapted for alternative spectral windows and pulse durations.

  16. Josephson junction spectrum analyzer for millimeter and submillimeter wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Larkin, S.Y.; Anischenko, S.E.; Khabayev, P.V. [State Research Center, Kiev (Ukraine)

    1994-12-31

    A prototype of the Josephson-effect spectrum analyzer developed for the millimeter-wave band is described. The measurement results for spectra obtained in the frequency band from 50 to 250 GHz are presented.

  17. Direct measurement of additional Ar-H2O vibration-rotation-tunneling bands in the millimeter-submillimeter range

    Science.gov (United States)

    Zou, Luyao; Widicus Weaver, Susanna L.

    2016-06-01

    Three new weak bands of the Ar-H2O vibration-rotation-tunneling spectrum have been measured in the millimeter wavelength range. These bands were predicted from combination differences based on previously measured bands in the submillimeter region. Two previously reported submillimeter bands were also remeasured with higher frequency resolution. These new measurements allow us to obtain accurate information on the Coriolis interaction between the 101 and 110 states. Here we report these results and the associated improved molecular constants.

  18. A Submillimeter HCN Laser in IRC +10216.

    Science.gov (United States)

    Schilke; Mehringer; Menten

    2000-01-01

    We report the detection of a strong submillimeter-wavelength HCN laser line at a frequency near 805 GHz toward the carbon star IRC +10216. This line, the J=9-8 rotational transition within the (0400) vibrationally excited state, is one of a series of HCN laser lines that were first detected in the laboratory in the early days of laser spectroscopy. Since its lower energy level is 4200 K above the ground state, the laser emission must arise from the innermost part of IRC +10216's circumstellar envelope. To better characterize this environment, we observed other, thermally emitting, vibrationally excited HCN lines and found that they, like the laser line, arise in a region of temperature approximately 1000 K that is located within the dust formation radius; this conclusion is supported by the line width of the laser. The (0400), J=9-8 laser might be chemically pumped and may be the only known laser (or maser) that is excited both in the laboratory and in space by a similar mechanism.

  19. SUBMILLIMETER LIGHTCURVES OF ASTEROIDS V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — Submillimeter lightcurves of large asteroids Ceres, Davida, Io, Juno, Pallas, Vesta, and Victoria, observed at the Heinrich-Hertz Submillimeter Telescope from...

  20. Objective assessment of intensive targeted treatment for solar lentigines using intense pulsed light with wavelengths between 500 and 635 nm

    Science.gov (United States)

    Tsunemi, Yuichiro; Kawashima, Makoto

    2015-01-01

    Background and Objectives Solar lentigines are commonly found in sun‐exposed areas of the body including hands, neck, or face. This study evaluates the efficacy of an intense pulsed light (IPL) device, with wavelengths between 500 and 635 nm and delivered with a targeted tip, for the treatment of solar lentigines on Japanese skin. Study Design/Materials and Methods Forty Japanese patients with solar lentigines received one IPL treatment with a targeted treatment tip that emits wavelengths between 500 and 635 nm and contact cooling. Pulses were delivered through a targeted tip to each lentigo until mild swelling and a gray color were observed. Digital photographs and gray level histogram values were taken pre‐ and post‐treatment, and patient assessments were recorded post‐treatment. Results Significant improvement was observed for all patients in digital photographs and mean values of gray level histograms (P Wiley Periodicals, Inc. PMID:26462982

  1. Multi-objective inverse design of sub-wavelength optical focusing structures for heat assisted magnetic recording

    Science.gov (United States)

    Bhargava, Samarth; Yablonovitch, Eli

    2014-09-01

    We report using Inverse Electromagnetic Design to computationally optimize the geometric shapes of metallic optical antennas or near-field transducers (NFTs) and dielectric waveguide structures that comprise a sub-wavelength optical focusing system for practical use in Heat Assisted Magnetic Recording (HAMR). This magnetic data-recording scheme relies on focusing optical energy to locally heat the area of a single bit, several hundred square nanometers on a hard disk, to the Curie temperature of the magnetic storage layer. There are three specifications of the optical system that must be met to enable HAMR as a commercial technology. First, to heat the media at scan rates upward of 10 m/s, ~1mW of light (<1% of typical laser diode output power) must be focused to a 30nm×30nm spot on the media. Second, the required lifetime of many years necessitates that the nano-scale NFT must not over-heat from optical absorption. Third, to avoid undesired erasing or interference of adjacent tracks on the media, there must be minimal stray optical radiation away from the hotspot on the hard disk. One cannot design the light delivery system by tackling each of these challenges independently, because they are governed by coupled electromagnetic phenomena. Instead, we propose multiobjective optimization using Inverse Electromagnetic Design in conjunction with a commercial 3D FDTD Maxwell's equations solver. We computationally generated designs of a metallic NFT and a high-index waveguide grating that meet the HAMR specifications simultaneously. Compared to a mock industry design, our proposed design has a similar optical coupling efficiency, ~3x improved suppression of stray optical radiation, and a 60% (280°C) reduction in NFT temperature rise. We also distributed the Inverse Electromagnetic Design software online so that industry partners can use it as a repeatable design process.

  2. Empirical multi-wavelength prediction method for very high energy gamma-ray emitting BL Lacertae objects

    Science.gov (United States)

    Fallah Ramazani, V.; Lindfors, E.; Nilsson, K.

    2017-12-01

    Aim: We have collected the most complete multi-wavelength (6.0-6.0 × 10-18 cm) dataset of very high energy (VHE) γ-ray emitting (TeV) BL Lacs, which are the most numerous extragalactic VHE sources. Using significant correlations between different bands, we aim to identify the best TeV BL Lac candidates that can be discovered by the current and next generation of imaging air Cherenkov telescopes. Methods: We formed five datasets from lower energy data, i.e. radio, mid-infrared, optical, X-rays, and GeV γ-ray, and five VHE γ-ray datasets to perform a correlation study between different bands and to construct the prediction method. The low energy datasets were averaged for individual sources, while the VHE γ-ray data were divided into subsets according to the flux state of the source. We then looked for significant correlations and determined their best-fit parameters. Using the best-fit parameters we predicted the level of VHE γ-ray flux for a sample of 182 BL Lacs, which have not been detected at TeV energies. We identified the most promising TeV BL Lac candidates based on the predicted VHE γ-ray flux for each source. Results: We found 14 significant correlations between radio, mid-infrared, optical, γ-ray, and VHE γ-ray bands. The correlation between optical and VHE γ-ray luminosity is established for the first time. We attribute this to the more complete sample and more accurate handling of host galaxy flux in our work. We found nine BL Lac candidates whose predicted VHE γ-ray flux is high enough for detection in less than 25 h with current imaging air Cherenkov telescopes. Full Tables A.1 and A.2 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/608/A68

  3. Nova Oph 2017 (TCP J17394608-2457555) detected at millimeter wavelengths

    Science.gov (United States)

    Kaminski, T.; Gehrz, R.

    2017-06-01

    Millimeter-wave continuum emission was detected in Nova Oph 2017 (ATel #10366, #10367) with the Submillimeter Array in Hawaii. The object was observed on July 20, 2017 in four spectral ranges: 224.3-232.3, 240.6-248.6, 336-344, and 352-360 GHz. The combined continuum flux in the two lower ranges (i.e., at a wavelength of 1.3 mm) is of 4.8 mJy, well above the noise with an rms of 0.6 mJy per beam.

  4. Observing the Sun at Radio Wavelengths: Current Status and Future Prospects

    Science.gov (United States)

    Bastian, T.; Gary, D.

    2012-12-01

    Radio emission from the Sun offers the means of probing thermal and non-thermal processes in the chromosphere and corona using diagnostics that are largely complementary to those available at optical wavelengths. This talk briefly reviews radio diagnostics and observing techniques and several of the science objectives motivating new and planned instrumentation, including coronal magnetography, magnetic energy release and particle acceleration, drivers of space weather, and the quiet solar atmosphere. New instrumentation includes ALMA, opening a new spectral window at millimeter and submillimeter wavelengths; and the Jansky Very Large Array (JVLA), a powerful new instrument operating at centimeter and decimeter wavelengths. A solar-dedicated instrument under construction is the Expanded Owens Valley Solar Array (EOVSA); and a planned, new, solar-dedicated facility is the Frequency Agile Solar Radiotelescope (FASR). EOVSA will soon pioneer dynamic imaging spectroscopy techniques. FASR will fully exploit these techniques as a general purpose radioheliograph designed to perform ultra-wideband dynamic imaging spectroscopy.

  5. Structured Antireflective Coating for Silicon at Submillimeter Frequencies

    Science.gov (United States)

    Padilla, Estefania

    2018-01-01

    Observations at millimeter and submillimeter wavelengths are useful for many astronomical studies, such as the polarization of the cosmic microwave background or the formation and evolution of galaxy clusters. In order to allow observations over a broad spectral bandwidth (approximatively from 70 to 420 GHz), innovative broadband anti-reflective (AR) optics must be utilized in submillimeter telescopes. Due to its low loss and high refractive index, silicon is a fine optical material at these frequencies, but an AR coating with multiple layers is required to maximize its transmission over a wide bandwidth. Structured multilayer AR coatings for silicon are currently being developed at Caltech and JPL. The development process includes the design of the structured layers with commercial electromagnetic simulation software, the fabrication by using deep reactive ion etching, and the test of the transmission and reflection of the patterned wafers. Geometrical 3D patterns have successfully been etched at the surface of the silicon wafers creating up to 2 layers with different effective refractive indices. The transmission and reflection of single AR layer wafers, measured between 75 and 330 GHz, are close to the simulation predictions. These results allow the development of new designs with 5 or 6 AR layers in order to improve the bandwidth and transmission of the silicon AR coatings.

  6. A Submillimeter Free Electron Laser

    Science.gov (United States)

    1985-09-30

    radiation fields sinale- etage M design and b) the uv-visible- generated by a single electron have an angar ir region using a two- etage M device...the UCSB M -dill be tested as a two- etage device. The range of wavelength that will be covered with this mode of operation is from the vacuum

  7. Faint Submillimeter Galaxies Behind Lensing Clusters

    Science.gov (United States)

    Hsu, Li-Yen; Lauchlan Cowie, Lennox; Barger, Amy J.; Desai, Vandana; Murphy, Eric J.

    2017-01-01

    Faint submillimeter galaxies are the major contributors to the submillimeter extragalactic background light and hence the dominant star-forming population in the dusty universe. Determining how much these galaxies overlap the optically selected samples is critical to fully account for the cosmic star formation history. Observations of massive cluster fields are the best way to explore this faint submillimeter population, thanks to gravitational lensing effects. We have been undertaking a lensing cluster survey with the SCUBA-2 camera on the James Clerk Maxwell Telescope to map nine galaxy clusters, including the northern five clusters in the HST Frontier Fields program. We have also been using the Submillimeter Array and the Very Large Array to determine the accurate positions of our detected sources. Our observations have discovered high-redshift dusty galaxies with far-infrared luminosities similar to that of the Milky Way or luminous infrared galaxies. Some of these galaxies are still undetected in deep optical and near-infrared images. These results suggest that a substantial amount of star formation in even the faint submillimeter population may be hidden from rest-frame optical surveys.

  8. SMA Submillimeter Observations of HL Tau: Revealing a Compact Molecular Outflow

    Science.gov (United States)

    Lumbreras, Alba M.; Zapata, Luis A.

    2014-04-01

    We present archival high angular resolution (~2'') 12CO(3-2) line and continuum submillimeter observations of the young stellar object HL Tau made with the Submillimeter Array. The 12CO(3-2) line observations reveal the presence of a compact and wide opening angle bipolar outflow with a northeast to southwest orientation (P.A. = 50°) that is associated with the optical and infrared jet emanating from HL Tau with a similar orientation. On the other hand, the 850 μm continuum emission observations exhibit a strong and compact source in the position of HL Tau that has a spatial size of ~200 × 70 AU with a P.A. = 145° and a dust mass of around 0.1 M ⊙. These physical parameters are in agreement with values obtained recently from millimeter observations. This submillimeter source is therefore related to the disk surrounding HL Tau.

  9. SMA submillimeter observations of HL Tau: revealing a compact molecular outflow

    Energy Technology Data Exchange (ETDEWEB)

    Lumbreras, Alba M.; Zapata, Luis A. [Centro de Radioastronomía y Astrofísica, UNAM, Morelia (Mexico)

    2014-04-01

    We present archival high angular resolution (∼2'') {sup 12}CO(3-2) line and continuum submillimeter observations of the young stellar object HL Tau made with the Submillimeter Array. The {sup 12}CO(3-2) line observations reveal the presence of a compact and wide opening angle bipolar outflow with a northeast to southwest orientation (P.A. = 50°) that is associated with the optical and infrared jet emanating from HL Tau with a similar orientation. On the other hand, the 850 μm continuum emission observations exhibit a strong and compact source in the position of HL Tau that has a spatial size of ∼200 × 70 AU with a P.A. = 145° and a dust mass of around 0.1 M {sub ☉}. These physical parameters are in agreement with values obtained recently from millimeter observations. This submillimeter source is therefore related to the disk surrounding HL Tau.

  10. Demonstration of Submillimeter Astrophysics Technology at Caltech Submillimeter Observatory Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The following are the objectives of this project:(1) Demonstration of 1600-element Kinetic Inductance Detector (KID) imaging array operating at 350 micron with near...

  11. Objectivity

    CERN Document Server

    Daston, Lorraine

    2010-01-01

    Objectivity has a history, and it is full of surprises. In Objectivity, Lorraine Daston and Peter Galison chart the emergence of objectivity in the mid-nineteenth-century sciences--and show how the concept differs from its alternatives, truth-to-nature and trained judgment. This is a story of lofty epistemic ideals fused with workaday practices in the making of scientific images. From the eighteenth through the early twenty-first centuries, the images that reveal the deepest commitments of the empirical sciences--from anatomy to crystallography--are those featured in scientific atlases, the compendia that teach practitioners what is worth looking at and how to look at it. Galison and Daston use atlas images to uncover a hidden history of scientific objectivity and its rivals. Whether an atlas maker idealizes an image to capture the essentials in the name of truth-to-nature or refuses to erase even the most incidental detail in the name of objectivity or highlights patterns in the name of trained judgment is a...

  12. SUBMILLIMETER FOLLOW-UP OF WISE-SELECTED HYPERLUMINOUS GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jingwen; Eisenhardt, Peter R. M.; Stern, Daniel; Assef, Roberto [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Tsai, Chao-Wei; Cutri, Roc; Griffith, Roger; Jarrett, Thomas [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Sayers, Jack; Bridge, Carrie [Division of Physics, Math and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Benford, Dominic [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Blain, Andrew [Department of Physics and Astronomy, University of Leicester, LE1 7RH Leicester (United Kingdom); Petty, Sara; Lake, Sean [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Bussmann, Shane [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS78, Cambridge, MA 02138 (United States); Comerford, Julia M.; Evans, Neal J. II [Department of Astronomy, University of Texas, Austin, TX 78731 (United States); Lonsdale, Carol [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Rho, Jeonghee [SETI Institute, 189 BERNARDO Avenue, Mountain View, CA 94043 (United States); Stanford, S. Adam, E-mail: jingwen.wu@jpl.nasa.gov [Department of Physics, University of California Davis, One Shields Avenue, Davis, CA 95616 (United States); and others

    2012-09-01

    We have used the Caltech Submillimeter Observatory (CSO) to follow-up a sample of Wide-field Infrared Survey Explorer (WISE) selected, hyperluminous galaxies, the so-called W1W2-dropout galaxies. This is a rare ({approx}1000 all-sky) population of galaxies at high redshift (peaks at z = 2-3), which are faint or undetected by WISE at 3.4 and 4.6 {mu}m, yet are clearly detected at 12 and 22 {mu}m. The optical spectra of most of these galaxies show significant active galactic nucleus activity. We observed 14 high-redshift (z > 1.7) W1W2-dropout galaxies with SHARC-II at 350-850 {mu}m, with nine detections, and observed 18 with Bolocam at 1.1 mm, with five detections. Warm Spitzer follow-up of 25 targets at 3.6 and 4.5 {mu}m, as well as optical spectra of 12 targets, are also presented in the paper. Combining WISE data with observations from warm Spitzer and CSO, we constructed their mid-IR to millimeter spectral energy distributions (SEDs). These SEDs have a consistent shape, showing significantly higher mid-IR to submillimeter ratios than other galaxy templates, suggesting a hotter dust temperature. We estimate their dust temperatures to be 60-120 K using a single-temperature model. Their infrared luminosities are well over 10{sup 13} L{sub Sun }. These SEDs are not well fitted with existing galaxy templates, suggesting they are a new population with very high luminosity and hot dust. They are likely among the most luminous galaxies in the universe. We argue that they are extreme cases of luminous, hot dust-obscured galaxies (DOGs), possibly representing a short evolutionary phase during galaxy merging and evolution. A better understanding of their long-wavelength properties needs ALMA as well as Herschel data.

  13. Faint submillimeter galaxies revealed by multifield deep ALMA observations: number counts, spatial clustering, and a dark submillimeter line emitter

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Yoshiaki; Ouchi, Masami; Momose, Rieko [Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Kurono, Yasutaka, E-mail: ono@icrr.u-tokyo.ac.jp [Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura, Santiago 763-0355 (Chile)

    2014-11-01

    We present the statistics of faint submillimeter/millimeter galaxies (SMGs) and serendipitous detections of a submillimeter/millimeter line emitter (SLE) with no multi-wavelength continuum counterpart revealed by the deep ALMA observations. We identify faint SMGs with flux densities of 0.1-1.0 mJy in the deep Band-6 and Band-7 maps of 10 independent fields that reduce cosmic variance effects. The differential number counts at 1.2 mm are found to increase with decreasing flux density down to 0.1 mJy. Our number counts indicate that the faint (0.1-1.0 mJy, or SFR{sub IR} ∼ 30-300 M {sub ☉} yr{sup –1}) SMGs contribute nearly a half of the extragalactic background light (EBL), while the remaining half of the EBL is mostly contributed by very faint sources with flux densities of <0.1 mJy (SFR{sub IR} ≲ 30 M {sub ☉} yr{sup –1}). We conduct counts-in-cells analysis with multifield ALMA data for the faint SMGs, and obtain a coarse estimate of galaxy bias, b {sub g} < 4. The galaxy bias suggests that the dark halo masses of the faint SMGs are ≲ 7 × 10{sup 12} M {sub ☉}, which is smaller than those of bright (>1 mJy) SMGs, but consistent with abundant high-z star-forming populations, such as sBzKs, LBGs, and LAEs. Finally, we report the serendipitous detection of SLE-1, which has no continuum counterparts in our 1.2 mm-band or multi-wavelength images, including ultra deep HST/WFC3 and Spitzer data. The SLE has a significant line at 249.9 GHz with a signal-to-noise ratio of 7.1. If the SLE is not a spurious source made by the unknown systematic noise of ALMA, the strong upper limits of our multi-wavelength data suggest that the SLE would be a faint galaxy at z ≳ 6.

  14. The millimeter and submillimeter spectrum of CF(+)

    Science.gov (United States)

    Plummer, G. M.; Anderson, T.; Herbst, E.; De Lucia, F. C.

    1986-01-01

    The application of a recently described technique for producing significantly enhanced concentrations of molecular ions for spectroscopic study to the detection and measurement of the millimeter and submillimeter wave spectrum of CF(+) is reported. The experimental procedure is discussed, and the measured absorption frequencies are shown and compared with those calculated from spectral constants. These constants are given together with those from the infrared spectrum by Kawaguchi and Hirota (1985).

  15. Solar Observations with the Atacama Large Millimeter/submillimeter Array

    Science.gov (United States)

    Wedemeyer, Sven

    2015-08-01

    The interferometric Atacama Large Millimeter/submillimeter Array (ALMA) has already demonstrated its impressive capabilities by observing a large variety of targets ranging from protoplanetary disks to galactic nuclei. ALMA is also capable of observing the Sun and has been used for five solar test campaigns so far. The technically challenging solar observing modes are currently under development and regular observations are expected to begin in late 2016.ALMA consists of 66 antennas located in the Chilean Andes at an altitude of 5000 m and is a true leap forward in terms of spatial resolution at millimeter wavelengths. The resolution of reconstructed interferometric images of the Sun is anticipated to be close to what current optical solar telescopes can achieve. In combination with the high temporal and spectral resolution, these new capabilities open up new parameter spaces for solar millimeter observations.The solar radiation at wavelengths observed by ALMA originates from the chromosphere, where the height of the sampled layer increases with selected wavelength. The continuum intensity is linearly correlated to the local gas temperature in the probed layer, which makes ALMA essentially a linear thermometer. During flares, ALMA can detect additional non-thermal emission contributions. Measurements of the polarization state facilitate the valuable determination of the chromospheric magnetic field. In addition, spectrally resolved observations of radio recombination and molecular lines may yield great diagnostic potential, which has yet to be investigated and developed.Many different scientific applications for a large range of targets from quiet Sun to active regions and prominences are possible, ranging from ultra-high cadence wave studies to flare observations. ALMA, in particular in combination with other ground-based and space-borne instruments, will certainly lead to fascinating new findings, which will advance our understanding of the atmosphere of our Sun

  16. Lightweight Thermally Stable Multi-Meter Aperture Submillimeter Reflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future astrophysics missions will require lightweight, thermally stable, submillimeter reflectors in sizes of 4m and greater. To date, graphite fiber reinforced...

  17. Wavefront Sensing and Control Technology for Submillimeter and Far-Infrared Space Telescopes

    Science.gov (United States)

    Redding, Dave

    2004-01-01

    The NGST wavefront sensing and control system will be developed to TRL6 over the next few years, including testing in a cryogenic vacuum environment with traceable hardware. Doing this in the far-infrared and submillimeter is probably easier, as some aspects of the problem scale with wavelength, and the telescope is likely to have a more stable environment; however, detectors may present small complications. Since this is a new system approach, it warrants a new look. For instance, a large space telescope based on the DART membrane mirror design requires a new actuation approach. Other mirror and actuation technologies may prove useful as well.

  18. Deciphering Debris Disk Structure with the Submillimeter Array

    Science.gov (United States)

    MacGregor, Meredith Ann

    2018-01-01

    More than 20% of nearby main sequence stars are surrounded by dusty disks continually replenished via the collisional erosion of planetesimals, larger bodies similar to asteroids and comets in our own Solar System. The material in these ‘debris disks’ is directly linked to the larger bodies such as planets in the system. As a result, the locations, morphologies, and physical properties of dust in these disks provide important probes of the processes of planet formation and subsequent dynamical evolution. Observations at millimeter wavelengths are especially critical to our understanding of these systems, since they are dominated by larger grains that do not travel far from their origin and therefore reliably trace the underlying planetesimal distribution. The Submillimeter Array (SMA) plays a key role in advancing our understanding of debris disks by providing sensitivity at the short baselines required to determine the structure of wide-field disks, such as the HR 8799 debris disk. Many of these wide-field disks are among the closest systems to us, and will serve as cornerstone templates for the interpretation of more distant, less accessible systems.

  19. SUBMILLIMETER ARRAY AND SPITZER OBSERVATIONS OF BOK GLOBULE CB 17: A CANDIDATE FIRST HYDROSTATIC CORE?

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xuepeng; Arce, Hector G.; Dunham, Michael M. [Department of Astronomy, Yale University, Box 208101, New Haven, CT 06520-8101 (United States); Zhang Qizhou; Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Launhardt, Ralf; Schmalzl, Markus; Henning, Thomas, E-mail: xuepeng.chen@yale.edu [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)

    2012-06-01

    We present high angular resolution Submillimeter Array (SMA) and Spitzer observations toward the Bok globule CB 17. SMA 1.3 mm dust continuum images reveal within CB 17 two sources with an angular separation of {approx}21'' ({approx}5250 AU at a distance of {approx}250 pc). The northwestern continuum source, referred to as CB 17 IRS, dominates the infrared emission in the Spitzer images, drives a bipolar outflow extending in the northwest-southeast direction, and is classified as a low-luminosity Class 0/I transition object (L{sub bol} {approx} 0.5 L{sub Sun }). The southeastern continuum source, referred to as CB 17 MMS, has faint dust continuum emission in the SMA 1.3 mm observations ({approx}6{sigma} detection; {approx}3.8 mJy), but is not detected in the deep Spitzer infrared images at wavelengths from 3.6 to 70 {mu}m. Its bolometric luminosity and temperature, estimated from its spectral energy distribution, are {<=}0.04 L{sub Sun} and {<=}16 K, respectively. The SMA CO (2-1) observations suggest that CB 17 MMS may drive a low-velocity molecular outflow ({approx}2.5 km s{sup -1}), extending in the east-west direction. Comparisons with prestellar cores and Class 0 protostars suggest that CB 17 MMS is more evolved than prestellar cores but less evolved than Class 0 protostars. The observed characteristics of CB 17 MMS are consistent with the theoretical predictions from radiative/magnetohydrodynamical simulations of a first hydrostatic core, but there is also the possibility that CB 17 MMS is an extremely low luminosity protostar deeply embedded in an edge-on circumstellar disk. Further observations are needed to study the properties of CB 17 MMS and to address more precisely its evolutionary stage.

  20. Adaptable radiative transfer innovations for submillimeter telescopes (ARTIST)

    DEFF Research Database (Denmark)

    Padovani, Marco; Jørgensen, Jes Kristian; Bertoldi, Frank

    2011-01-01

    Submillimeter observations are a key for answering many of the big questions in modern-day astrophysics, such as how stars and planets form, how galaxies evolve, and how material cycles through stars and the interstellar medium. With the upcoming large submillimeter facilities ALMA and Herschel...

  1. RESOLVED MILLIMETER-WAVELENGTH OBSERVATIONS OF DEBRIS DISKS AROUND SOLAR-TYPE STARS

    Energy Technology Data Exchange (ETDEWEB)

    Steele, Amy; Hughes, A. Meredith [Department of Astronomy, Van Vleck Observatory, Wesleyan University, 96 Foss Hill Drive, Middletown, CT, 06459 (United States); Carpenter, John [Division of Physics, Mathematics, and Astronomy, MC249-17, California Institute of Technology, Pasadena, CA 91125 (United States); Ricarte, Angelo [J. W. Gibbs Laboratory, Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States); Andrews, Sean M.; Wilner, David J. [Harvard-Smithsonian Center for Astrophysics, MS-42, 60 Garden Street, Cambridge, MA 02138 (United States); Chiang, Eugene, E-mail: asteele@wesleyan.edu [Department of Astronomy, 501 Campbell Hall, University of California, Berkeley, CA 94720-3411 (United States)

    2016-01-01

    The presence of debris disks around young main-sequence stars hints at the existence and structure of planetary systems. Millimeter-wavelength observations probe large grains that trace the location of planetesimal belts. The Formation and Evolution of Planetary Systems Spitzer Legacy survey of nearby young solar analogues yielded a sample of five debris disk-hosting stars with millimeter flux suitable for interferometric follow-up. We present observations with the Submillimeter Array (SMA) and the Combined Array for Research in Millimeter-wave Astronomy at ∼2″ resolution that spatially resolve the debris disks around these nearby (d ∼ 50 pc) stars. Two of the five disks (HD 377, HD 8907) are spatially resolved for the first time and one (HD 104860) is resolved at millimeter wavelengths for the first time. We combine our new observations with archival SMA and Atacama Large Millimeter/Submillimeter Array data to enable a uniform analysis of the full five-object sample. We simultaneously model the broadband photometric data and resolved millimeter visibilities to constrain the dust temperatures and disk morphologies, and perform a Markov Chain Monte Carlo analysis to fit for basic structural parameters. We find that the radii and widths of the cold outer belts exhibit properties consistent with scaled-up versions of the Solar System's Kuiper Belt. All the disks exhibit characteristic grain sizes comparable to the blowout size, and all the resolved observations of emission from large dust grains are consistent with an axisymmetric dust distribution to within the uncertainties. These results are consistent with comparable studies carried out at infrared wavelengths.

  2. EVIDENCE FOR ENVIRONMENTAL CHANGES IN THE SUBMILLIMETER DUST OPACITY

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Peter G.; Roy, Arabindo; Miville-Deschenes, Marc-Antoine [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Bontemps, Sylvain [Observatoire de Bordeaux, BP 89, F-33270 Floirac (France); Ade, Peter A. R.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip [Department of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff, CF24 3AA (United Kingdom); Bock, James J. [Jet Propulsion Laboratory, Pasadena, CA 91109-8099 (United States); Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Devlin, Mark J.; Dicker, Simon R.; Klein, Jeff [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Gundersen, Joshua O. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Carol Gables, FL 33146 (United States); Hughes, David H. [Instituto Nacional de Astrofisica Optica y Electronica (INAOE), Aptdo. Postal 51 y 72000 Puebla (Mexico); Netterfield, Calvin B. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Olmi, Luca [INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 (Italy); Patanchon, Guillaume [Laboratoire APC, 10, rue Alice Domon et Leonie Duquet F-75205 Paris (France); and others

    2012-05-20

    The submillimeter opacity of dust in the diffuse interstellar medium (ISM) in the Galactic plane has been quantified using a pixel-by-pixel correlation of images of continuum emission with a proxy for column density. We used multi-wavelength continuum data: three Balloon-borne Large Aperture Submillimeter Telescope bands at 250, 350, and 500 {mu}m and one IRAS band at 100 {mu}m. The proxy is the near-infrared color excess, E(J - K{sub s}), obtained from the Two Micron All Sky Survey. Based on observations of stars, we show how well this color excess is correlated with the total hydrogen column density for regions of moderate extinction. The ratio of emission to column density, the emissivity, is then known from the correlations, as a function of frequency. The spectral distribution of this emissivity can be fit by a modified blackbody, whence the characteristic dust temperature T and the desired opacity {sigma}{sub e}(1200) at 1200 GHz or 250 {mu}m can be obtained. We have analyzed 14 regions near the Galactic plane toward the Vela molecular cloud, mostly selected to avoid regions of high column density (N{sub H} > 10{sup 22} cm{sup -2}) and small enough to ensure a uniform dust temperature. We find {sigma}{sub e}(1200) is typically (2-4) Multiplication-Sign 10{sup -25} cm{sup 2} H{sup -1} and thus about 2-4 times larger than the average value in the local high Galactic latitude diffuse atomic ISM. This is strong evidence for grain evolution. There is a range in total power per H nucleon absorbed (and re-radiated) by the dust, reflecting changes in the strength of the interstellar radiation field and/or the dust absorption opacity. These changes in emission opacity and power affect the equilibrium T, which is typically 15 K, colder than at high latitudes. Our analysis extends, to higher opacity and lower temperature, the trend of increasing {sigma}{sub e}(1200) with decreasing T that was found at high latitudes. The recognition of changes in the emission opacity

  3. The JCMT Transient Survey: Detection of Submillimeter Variability in a Class I Protostar EC 53 in Serpens Main

    Science.gov (United States)

    Yoo, Hyunju; Lee, Jeong-Eun; Mairs, Steve; Johnstone, Doug; Herczeg, Gregory J.; Kang, Sung-ju; Kang, Miju; Cho, Jungyeon; The JCMT Transient Team

    2017-11-01

    During the protostellar phase of stellar evolution, accretion onto the star is expected to be variable, but this suspected variability has been difficult to detect because protostars are deeply embedded. In this paper, we describe a submillimeter luminosity burst of the Class I protostar EC 53 in Serpens Main, the first variable found during our dedicated JCMT/SCUBA-2 monitoring program of eight nearby star-forming regions. EC 53 remained quiescent for the first six months of our survey, from 2016 February to August. The submillimeter emission began to brighten in 2016 September, reached a peak brightness of 1.5 times the faint state, and has been decaying slowly since 2017 February. The change in submillimeter brightness is interpreted as dust heating in the envelope, generated by a luminosity increase of the protostar of a factor of ≥4. The 850 μm light curve resembles the historical K-band light curve, which varies by a factor of ˜6 with a 543 period and is interpreted as accretion variability excited by interactions between the accretion disk and a close binary system. The predictable detections of accretion variability observed at both near-infrared and submillimeter wavelengths make the system a unique test-bed, enabling us to capture the moment of the accretion burst and to study the consequences of the outburst on the protostellar disk and envelope.

  4. Millimeter and submillimeter spectrum of propylene oxide

    Science.gov (United States)

    Mesko, A. J.; Zou, Luyao; Carroll, P. Brandon; Widicus Weaver, Susanna L.

    2017-05-01

    The spectrum of propylene oxide was collected from 70 GHz to 1 THz using direct absorption millimeter and submillimeter spectroscopy. Analysis of the spectrum was performed using the SPFIT/SPCAT programs for the A state. A full internal rotor analysis was performed using the XIAM program. The barrier to internal rotation of the methyl group was determined to be 893 cm-1. The precision of the rotation constants, centrifugal distortion constants, and internal rotor parameters was increased over the results reported by previous low-frequency studies. The results of this laboratory study and the associated analysis, as well as a spectral prediction for the ground vibrational state of propylene oxide, are presented.

  5. Millimeter and Submillimeter Observations of Ceres

    Science.gov (United States)

    Kuan, Yi-Jehng; Chuang, Yo-Ling; Tseng, Wei-Ling; Coulson, Iain M.; Chung, Ming-Chi

    2016-07-01

    1 Ceres is the largest celestial body in the Main Asteroid Belt and is also the sole dwarf planet in the inner solar system. Water vapor from small icy solar-system bodies, including Ceres and Europa, was detected by Herschel infrared space telescope recently. Data taken from Dawn spacecraft suggest that a subsurface layer of briny water ice, together with ammonia-rich clays, may exist on Ceres. We hence observed Ceres using the 15-m James Clerk Maxwell Telescope (JCMT) to search for other atmospheric molecules besides H _{2}O. Submillimeter continuum observations employing SCUBA-2 were also carried out. Here we report the tentative detection of hydrogen cyanide in the atmosphere of Ceres. If confirmed, our finding could imply that Ceres may have a comet-like chemical composition. However, further observational confirmation and more detailed analysis is needed.

  6. Photon caliper to achieve submillimeter positioning accuracy

    Science.gov (United States)

    Gallagher, Kyle J.; Wong, Jennifer; Zhang, Junan

    2017-09-01

    The purpose of this study was to demonstrate the feasibility of using a commercial two-dimensional (2D) detector array with an inherent detector spacing of 5 mm to achieve submillimeter accuracy in localizing the radiation isocenter. This was accomplished by delivering the Vernier ‘dose’ caliper to a 2D detector array where the nominal scale was the 2D detector array and the non-nominal Vernier scale was the radiation dose strips produced by the high-definition (HD) multileaf collimators (MLCs) of the linear accelerator. Because the HD MLC sequence was similar to the picket fence test, we called this procedure the Vernier picket fence (VPF) test. We confirmed the accuracy of the VPF test by offsetting the HD MLC bank by known increments and comparing the known offset with the VPF test result. The VPF test was able to determine the known offset within 0.02 mm. We also cross-validated the accuracy of the VPF test in an evaluation of couch hysteresis. This was done by using both the VPF test and the ExacTrac optical tracking system to evaluate the couch position. We showed that the VPF test was in agreement with the ExacTrac optical tracking system within a root-mean-square value of 0.07 mm for both the lateral and longitudinal directions. In conclusion, we demonstrated the VPF test can determine the offset between a 2D detector array and the radiation isocenter with submillimeter accuracy. Until now, no method to locate the radiation isocenter using a 2D detector array has been able to achieve such accuracy.

  7. Observing the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA): High-Resolution Interferometric Imaging

    Science.gov (United States)

    Shimojo, M.; Bastian, T. S.; Hales, A. S.; White, S. M.; Iwai, K.; Hills, R. E.; Hirota, A.; Phillips, N. M.; Sawada, T.; Yagoubov, P.; Siringo, G.; Asayama, S.; Sugimoto, M.; Brajša, R.; Skokić, I.; Bárta, M.; Kim, S.; de Gregorio-Monsalvo, I.; Corder, S. A.; Hudson, H. S.; Wedemeyer, S.; Gary, D. E.; De Pontieu, B.; Loukitcheva, M.; Fleishman, G. D.; Chen, B.; Kobelski, A.; Yan, Y.

    2017-07-01

    Observations of the Sun at millimeter and submillimeter wavelengths offer a unique probe into the structure, dynamics, and heating of the chromosphere; the structure of sunspots; the formation and eruption of prominences and filaments; and energetic phenomena such as jets and flares. High-resolution observations of the Sun at millimeter and submillimeter wavelengths are challenging due to the intense, extended, low-contrast, and dynamic nature of emission from the quiet Sun, and the extremely intense and variable nature of emissions associated with energetic phenomena. The Atacama Large Millimeter/submillimeter Array (ALMA) was designed with solar observations in mind. The requirements for solar observations are significantly different from observations of sidereal sources and special measures are necessary to successfully carry out this type of observations. We describe the commissioning efforts that enable the use of two frequency bands, the 3-mm band (Band 3) and the 1.25-mm band (Band 6), for continuum interferometric-imaging observations of the Sun with ALMA. Examples of high-resolution synthesized images obtained using the newly commissioned modes during the solar-commissioning campaign held in December 2015 are presented. Although only 30 of the eventual 66 ALMA antennas were used for the campaign, the solar images synthesized from the ALMA commissioning data reveal new features of the solar atmosphere that demonstrate the potential power of ALMA solar observations. The ongoing expansion of ALMA and solar-commissioning efforts will continue to enable new and unique solar observing capabilities.

  8. Dual-wavelength phase-shifting digital holography selectively extracting wavelength information from wavelength-multiplexed holograms.

    Science.gov (United States)

    Tahara, Tatsuki; Mori, Ryota; Kikunaga, Shuhei; Arai, Yasuhiko; Takaki, Yasuhiro

    2015-06-15

    Dual-wavelength phase-shifting digital holography that selectively extracts wavelength information from five wavelength-multiplexed holograms is presented. Specific phase shifts for respective wavelengths are introduced to remove the crosstalk components and extract only the object wave at the desired wavelength from the holograms. Object waves in multiple wavelengths are selectively extracted by utilizing 2π ambiguity and the subtraction procedures based on phase-shifting interferometry. Numerical results show the validity of the proposed technique. The proposed technique is also experimentally demonstrated.

  9. Black Holes and Sub-millimeter Dimensions

    CERN Document Server

    Argyres, Philip C; March-Russell, John David; Argyres, Philip C.; Dimopoulos, Savas; March-Russell, John

    1998-01-01

    Recently, a new framework for solving the hierarchy problem was proposed which does not rely on low energy supersymmetry or technicolor. The fundamental Planck mass is at a TeV and the observed weakness of gravity at long distances is due the existence of new sub-millimeter spatial dimensions. In this letter, we study how the properties of black holes are altered in these theories. Small black holes---with Schwarzschild radii smaller than the size of the new spatial dimensions---are quite different. They are bigger, colder, and longer-lived than a usual $(3+1)$-dimensional black hole of the same mass. Furthermore, they primarily decay into harmless bulk graviton modes rather than standard-model degrees of freedom. We discuss the interplay of our scenario with the holographic principle. Our results also have implications for the bounds on the spectrum of primordial black holes (PBHs) derived from the photo-dissociation of primordial nucleosynthesis products, distortion of the diffuse gamma-ray spectrum, overcl...

  10. Development Of A Multicolor Sub/millimeter Camera Using Microwave Kinetic Inductance Detectors

    Science.gov (United States)

    Schlaerth, James A.; Czakon, N. G.; Day, P. K.; Downes, T. P.; Duan, R.; Glenn, J.; Golwala, S. R.; Hollister, M. I.; LeDuc, H. G.; Maloney, P. R.; Mazin, B. A.; Noroozian, O.; Sayers, J.; Siegel, S.; Vayonakis, A.; Zmuidzinas, J.

    2011-01-01

    Microwave Kinetic Inductance Detectors (MKIDs) are superconducting resonators useful for detecting light from the millimeter-wave to the X-ray. These detectors are easily multiplexed, as the resonances can be tuned to slightly different frequencies, allowing hundreds of detectors to be read out simultaneously using a single feedline. The Multicolor Submillimeter Inductance Camera, MUSIC, will use 2304 antenna-coupled MKIDs in multicolor operation, with bands centered at wavelengths of 0.85, 1.1, 1.3 and 2.0 mm, beginning in 2011. Here we present the results of our demonstration instrument, DemoCam, containing a single 3-color array with 72 detectors and optics similar to MUSIC. We present sensitivities achieved at the telescope, and compare to those expected based upon laboratory tests. We explore the factors that limit the sensitivity, in particular electronics noise, antenna efficiency, and excess loading. We discuss mitigation of these factors, and how we plan to improve sensitivity to the level of background-limited performance for the scientific operation of MUSIC. Finally, we note the expected mapping speed and contributions of MUSIC to astrophysics, and in particular to the study of submillimeter galaxies. This research has been funded by grants from the National Science Foundation, the Gordon and Betty Moore Foundation, and the NASA Graduate Student Researchers Program.

  11. Solar Flash Sub-Millimeter Wave Range Spectrum Part Radiation Modeling

    Directory of Open Access Journals (Sweden)

    V. Yu. Shustikov

    2015-01-01

    Full Text Available Currently, solar flares are under observation on the RT-7.5 radio telescope of BMSTU. This telescope operates in a little-studied range of the spectrum, at wavelengths of 3.2 and 2.2 mm (93 and 140 GHz, thereby providing unique information about parameters of the chromosphere plasma and zone of the temperature minimum. Observations on various instruments provided relatively small amount of data on the radio emission flare at frequencies close to 93 GHz, and at frequency of 140 GHz such observations were not carried out. For these reasons, data collected from the RT-7.5 radio telescope are of high value (Shustikov et al., 2012.This work describes modeling and gives interpretation of the reason for raising flux density spectrum of sub-millimeter radio frequency emission using as an example the GOES flare of class M 5.3 occurred on 04.07.2012 in the active region 11515. This flare was observed on the RT-7.5 radio telescope of BMSTU and was described by Shustikov et al. (2012 and by Smirnova et al. (2013, where it has been suggested that the reason for raising radio frequency emission is a bremsstrahlung of the thermal electrons in the hot plasma of the solar chromosphere. Rough estimates of the plasma temperature at the flare source were obtained.This paper proposes model calculations of the flux density spectrum of the sub-millimeter radio emission based on the gyrosynchrotron Fleischman-Kuznetsov code (Fleishman & Kuznetsov, 2010. Section 1 briefly describes observational data, tools and processing methods used in the work. Section 2 shows results of modeling the flare radio emission. Section 3 discusses results and conclusions.Numerical modeling the sub-millimeter part of the spectrum of the radio flux density for the GOES flare of class M5.3 has been carried out. This flare occurred in the active region 11515 on 04.07.2012. Modeling was based on the observations on the BMSTU’s RT-7.5 radio telescope.The paper draws conclusion based on the

  12. Fast computation of the Narcissus reflection coefficient for the Herschel far-infrared/submillimeter-wave Cassegrain telescope

    Science.gov (United States)

    Lucke, Robert L.; Fischer, Jacqueline; Polegre, Arturo M.; Beintema, Douwe A.

    2005-10-01

    Placement of a scatter cone at the center of the secondary of a Cassegrain telescope greatly reduces Narcissus reflection. To calculate the remaining Narcissus reflection, a time-consuming physical optics code such as GRASP8 is often used to model the effects of reflection and diffraction. Fortunately, the Cassegrain geometry is sufficiently simple that a combination of theoretical analysis and Fourier propagation can yield rapid, accurate results at submillimeter wavelengths. We compare these results with those from GRASP8 for the heterodyne instrument for the far-infrared on the Herschel Space Observatory and confirm the effectiveness of the chosen scatter cone design.

  13. Infrared and submillimeter space missions in the coming decade programmes, programmatics, and technology

    CERN Document Server

    Sauvage, Marc; Gallais, Pascal; Vigroux, Laurent

    1996-01-01

    A revolution similar to that brought by CCDs to visible astronomy is still ahead in IR and submillimeter astronomy. There is certainly no wavelength range which has, over the past several years, seen such impressive advances in technology: large-scale detector arrays, new designs for cooling in space, lightweight mirror technologies. Scientific cases for observing the cold universe are outstanding. Observations in the FIR/Submm range will provide answers to such fundamental questions as: What is the spectrum of the primordial fluctuations? How do primeval galaxies look? What are the first stages of star formation? Most of the international space missions that have been triggered by these questions are presented in detail here. Technological issues raised by these missions are reviewed, as are the most recent achievements in cooling and detector technologies.

  14. Gravitational lens models based on submillimeter array imaging of Herschel -selected strongly lensed sub-millimeter galaxies at z > 1.5

    Energy Technology Data Exchange (ETDEWEB)

    Bussmann, R. S.; Gurwell, M. A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Pérez-Fournon, I. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Amber, S. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Calanog, J.; De Bernardis, F.; Wardlow, J. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); Fu, Hai [Department of Physics and Astronomy, The University of Iowa, 203 Van Allen Hall, Iowa City, IA 52242 (United States); Harris, A. I. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Krips, M. [Institut de RadioAstronomie Millimétrique, 300 Rue de la Piscine, Domaine Universitaire, 38406 Saint Martin d' Hères (France); Lapi, A. [Department Fisica, Univ. Tor Vergata, Via Ricerca Scientifica 1, 00133 Rome, Italy and SISSA, Via Bonomea 265, 34136 Trieste (Italy); Maiolino, R. [Cavendish Laboratory, University of Cambridge, 19 J.J. Thomson Ave., Cambridge CB3 OHE (United Kingdom); Omont, A. [Institut d' Astrophysique de Paris, UMR 7095, CNRS, UPMC Univ. Paris 06, 98bis boulevard Arago, F-75014 Paris (France); Riechers, D. [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Rd, Piscataway, NJ 08854 (United States); Birkinshaw, M. [HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); and others

    2013-12-10

    Strong gravitational lenses are now being routinely discovered in wide-field surveys at (sub-)millimeter wavelengths. We present Submillimeter Array (SMA) high-spatial resolution imaging and Gemini-South and Multiple Mirror Telescope optical spectroscopy of strong lens candidates discovered in the two widest extragalactic surveys conducted by the Herschel Space Observatory: the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). From a sample of 30 Herschel sources with S {sub 500} > 100 mJy, 21 are strongly lensed (i.e., multiply imaged), 4 are moderately lensed (i.e., singly imaged), and the remainder require additional data to determine their lensing status. We apply a visibility-plane lens modeling technique to the SMA data to recover information about the masses of the lenses as well as the intrinsic (i.e., unlensed) sizes (r {sub half}) and far-infrared luminosities (L {sub FIR}) of the lensed submillimeter galaxies (SMGs). The sample of lenses comprises primarily isolated massive galaxies, but includes some groups and clusters as well. Several of the lenses are located at z {sub lens} > 0.7, a redshift regime that is inaccessible to lens searches based on Sloan Digital Sky Survey spectroscopy. The lensed SMGs are amplified by factors that are significantly below statistical model predictions given the 500 μm flux densities of our sample. We speculate that this may reflect a deficiency in our understanding of the intrinsic sizes and luminosities of the brightest SMGs. The lensed SMGs span nearly one decade in L {sub FIR} (median L {sub FIR} = 7.9 × 10{sup 12} L {sub ☉}) and two decades in FIR luminosity surface density (median Σ{sub FIR} = 6.0 × 10{sup 11} L {sub ☉} kpc{sup –2}). The strong lenses in this sample and others identified via (sub-)mm surveys will provide a wealth of information regarding the astrophysics of galaxy formation and evolution over a wide range in redshift.

  15. DIRECT DETECTION OF PRECURSORS OF GAS GIANTS FORMED BY GRAVITATIONAL INSTABILITY WITH THE ATACAMA LARGE MILLIMETER/SUBMILLIMETER ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Lucio [Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Peters, Thomas [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Pineda, Jaime E. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Wadsley James; Rogers, Patrick, E-mail: p.rogers@marianopolis.edu [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada)

    2016-06-01

    Phases of gravitational instability are expected in the early phases of disk evolution, when the disk mass is still a substantial fraction of the mass of the star. Disk fragmentation into sub-stellar objects could occur in the cold exterior part of the disk. Direct detection of massive gaseous clumps on their way to collapse into gas giant planets would offer an unprecedented test of the disk instability model. Here we use state-of-the-art 3D radiation-hydro simulations of disks undergoing fragmentation into massive gas giants, post-processed with RADMC-3D to produce dust continuum emission maps. These are then fed into the Common Astronomy Software Applications (CASA) ALMA simulator. The synthetic maps show that both overdense spiral arms and actual clumps at different stages of collapse can be detected with the Atacama Large Millimeter/submillimeter Array (ALMA) in the full configuration at the distance of the Ophiuchus star forming region (125 pc). The detection of clumps is particularly effective at shorter wavelengths (690 GHz) combining two resolutions with multi-scale clean. Furthermore, we show that a flux-based estimate of the mass of a protoplanetary clump can be comparable to a factor of three higher than the gravitationally bound clump mass. The estimated mass depends on the assumed opacity, and on the gas temperature, which should be set using the input of radiation-hydro simulations. We conclude that ALMA has the capability to detect “smoking gun” systems that are a signpost of the disk instability model for gas giant planet formation.

  16. Submillimeter-resolution radiography of shielded structures with laser-accelerated electron beams

    Directory of Open Access Journals (Sweden)

    Vidya Ramanathan

    2010-10-01

    Full Text Available We investigate the use of energetic electron beams for high-resolution radiography of flaws embedded in thick solid objects. A bright, monoenergetic electron beam (with energy >100  MeV was generated by the process of laser-wakefield acceleration through the interaction of 50-TW, 30-fs laser pulses with a supersonic helium jet. The high energy, low divergence, and small source size of these beams make them ideal for high-resolution radiographic studies of cracks or voids embedded in dense materials that are placed at a large distance from the source. We report radiographic imaging of steel with submillimeter resolution.

  17. Submillimeter-Resolution Radiography of Shielded Structures with Laser-Accelerated Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Ramanathan, Vidya [University of Nebraska, Lincoln; Banerjee, Sudeep [University of Nebraska, Lincoln; Powell, Nathan [University of Nebraska, Lincoln; Cummingham, N. J. [University of Nebraska, Lincoln; Chandler-Smith, Nate [University of Nebraska, Lincoln; Zhao, Kun [University of Nebraska, Lincoln; Brown, Kevin [University of Nebraska, Lincoln; Umstadter, Donald [University of Nebraska, Lincoln; Clarke, Shaun [University of Michigan; Pozzi, Sara [University of Michigan; Beene, James R [ORNL; Vane, C Randy [ORNL; Schultz, David Robert [ORNL

    2010-10-01

    We investigate the use of energetic electron beams for high-resolution radiography of flaws embedded in thick solid objects. A bright, monoenergetic electron beam (with energy >100 MeV) was generated by the process of laser-wakefield acceleration through the interaction of 50-TW, 30-fs laser pulses with a supersonic helium jet. The high energy, low divergence, and small source size of these beams make them ideal for high-resolution radiographic studies of cracks or voids embedded in dense materials that are placed at a large distance from the source. We report radiographic imaging of steel with submillimeter resolution.

  18. Probing Galaxy Formation and Evolution with Space Born Sub-Millimeter Telescopes

    Science.gov (United States)

    Dwek, Eli; Arendt, Richard G.; Moseley, Harvey; Benford, Dominic; Shafer, Richard; Mather, John; Oegerle, William (Technical Monitor)

    2002-01-01

    A major unresolved question in cosmology is how the complex system of galaxies we see in the present universe evolved from an almost perfectly smooth beginning. Multiwavelength observations of galaxies have revealed that a significant fraction of their UV-visible starlight is absorbed and reradiated by dust at infrared JR) and submillimeter wavelengths. The cumulative IR-submm. emission from galaxies since the epoch of recombination, the cosmic IR background, has recently been recorded by the COBE satellite. The COBE observations in combination with recent submm surveys conducted with the SCUBA on the 15 m JCMT have shown that most of the radiation from star formation that has taken place in the early stages of galaxy evolution is reradiated by dust at submm wavelengths. Therefore, submm telescopes offer a unique probe of the early stages of galaxy formation and evolution. This talk will: (1) consider the impact of telescope diameter on the depth of the survey (what redshift can be probed) at different wavelengths; (2) discuss the relative scientific merits of high-resolution narrow-field surveys versus lower resolution deep surveys; and (3) show how both strategies offer complementary information crucial to our understanding of the structure and evolution of galaxies in the universe.

  19. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers.......Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers....

  20. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on air-optical wavelength converter types based on semiconductor optical amplifiers.......Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on air-optical wavelength converter types based on semiconductor optical amplifiers....

  1. Arrays of Bolometers for Far-infrared and Submillimeter Astronomy

    Science.gov (United States)

    Chuss, D. T.; Allen, C. A.; Babu, S.; Benford, D. J.; Dotson, J. L.; Dowell, C. D.; Jhabvala, M.; Harper, D. A.; Moseley, S. Harvey; Silverberg, R. F.; Staguhn, J. G.; Voellmer, G.; Wollack, E. J.

    We describe 12 x 32 arrays of semiconducting cryogenic bolometers designed for use in far-infrared and submillimeter cameras. These 12 x 32 arrays are constructed from 1 x 32 monolithic pop-up detectors developed at NASA Goddard Space Flight Center. The pop-up technology allows the construction of large arrays with high filling factors that provide efficient use of space in the focal planes of far-infrared and submillimeter astronomical instruments. This directly leads to a significant decrease in integration time. The prototype array is currently operating in the second generation Submillimeter High Angular Resolution Camera (SHARC II), a facility instrument in use at the Caltech Submillimeter Observatory (CSO). The elements of this array employ a bismuth absorber coating and quarter wave backshort to optimize the bolometer absorption for passbands centered at 350 and 450 microns. A second array is to be installed in the High-resolution Airborne Widebandwidth Camera (HAWC), a far-infrared imaging camera for the Stratospheric Observatory for Infrared Astronomy (SOFIA). This array has been completed and is now awaiting integration into the HAWC test cryostat. HAWC is scheduled for commissioning in 2005. The HAWC array employs titanium-gold absorbers and is optimized for uniform absorption from 40 to 300 microns to accommodate all four of its far-infrared passbands. We describe the details of the HAWC array construction including the mechanical design and electrical characterization of the constituent linear arrays.

  2. Two bolometer arrays for far-infrared and submillimeter astronomy

    Science.gov (United States)

    Silverberg, Robert F.; Allen, Christine A.; Babu, Sachidananda R.; Benford, Dominic J.; Chuss, David T.; Dotson, Jessie L.; Dowell, Charles D.; Harper, Doyle A.; Jhabvala, Murzy D.; Loewenstein, Robert F.; Moseley, S. H., Jr.; Staguhn, Johannes G.; Voellmer, George M.; Wollack, Edward J.

    2004-10-01

    We describe the development, construction, and testing of two 384 element arrays of ion-implanted semiconducting cryogenic bolometers designed for use in far-infrared and submillimeter cameras. These two dimensional arrays are assembled from a number of 32 element linear arrays of monolithic Pop-Up bolometer Detectors (PUD) developed at NASA/Goddard Space Flight Center. PUD technology allows the construction of large, high filling factor, arrays that make efficient use of available focal plane area in far-infrared and submillimeter astronomical instruments. Such arrays can be used to provide a significant increase in mapping speed over smaller arrays. A prototype array has been delivered and integrated into a ground-based camera, the Submillimeter High Angular Resolution Camera (SHARC II), a facility instrument at the Caltech Submillimeter Observatory (CSO). A second array has recently been delivered for integration into the High-resolution Airborne Widebandwidth Camera (HAWC), a far-infrared imaging camera for the Stratospheric Observatory for Infrared Astronomy (SOFIA). HAWC is scheduled for commissioning in 2005.

  3. Submillimeter Wave Antenna With Slow Wave Feed Line

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Krozer, Viktor; Kotiranta, Mikko

    2009-01-01

    Submillimeter wave radiation, which is also referred to as terahertz radiation, has not been extensively explored until recently due to a lack of reliable components and devices in this frequency range. Current advances in technology have made it possible to explore this portion of the electromag...

  4. Solar Science with the Atacama Large Millimeter/Submillimeter Array—A New View of Our Sun

    Science.gov (United States)

    Wedemeyer, S.; Bastian, T.; Brajša, R.; Hudson, H.; Fleishman, G.; Loukitcheva, M.; Fleck, B.; Kontar, E. P.; De Pontieu, B.; Yagoubov, P.; Tiwari, S. K.; Soler, R.; Black, J. H.; Antolin, P.; Scullion, E.; Gunár, S.; Labrosse, N.; Ludwig, H.-G.; Benz, A. O.; White, S. M.; Hauschildt, P.; Doyle, J. G.; Nakariakov, V. M.; Ayres, T.; Heinzel, P.; Karlicky, M.; Van Doorsselaere, T.; Gary, D.; Alissandrakis, C. E.; Nindos, A.; Solanki, S. K.; Rouppe van der Voort, L.; Shimojo, M.; Kato, Y.; Zaqarashvili, T.; Perez, E.; Selhorst, C. L.; Barta, M.

    2016-04-01

    The Atacama Large Millimeter/submillimeter Array (ALMA) is a new powerful tool for observing the Sun at high spatial, temporal, and spectral resolution. These capabilities can address a broad range of fundamental scientific questions in solar physics. The radiation observed by ALMA originates mostly from the chromosphere—a complex and dynamic region between the photosphere and corona, which plays a crucial role in the transport of energy and matter and, ultimately, the heating of the outer layers of the solar atmosphere. Based on first solar test observations, strategies for regular solar campaigns are currently being developed. State-of-the-art numerical simulations of the solar atmosphere and modeling of instrumental effects can help constrain and optimize future observing modes for ALMA. Here we present a short technical description of ALMA and an overview of past efforts and future possibilities for solar observations at submillimeter and millimeter wavelengths. In addition, selected numerical simulations and observations at other wavelengths demonstrate ALMA's scientific potential for studying the Sun for a large range of science cases.

  5. Observational Approach to Molecular Cloud Evolutation with the Submillimeter-Wave CI Lines

    Science.gov (United States)

    Oka, T.; Yamamoto, S.

    Neutral carbon atoms (CI) play important roles both in chemistry and cooling processes of interstellar molecular clouds. It is thus crucial to explore its large area distribution to obtain information on formation processes and thermal balance of molecular clouds. However, observations of the submillimeter-wave CI lines have been limited to small areas around some representative objects. We have constructed a 1.2 m submillimeter-wave telescope at the summit of Mt.Fuji. The telescope was designed for the exclusive use of surveying molecular clouds in two submillimeter-wave CI lines, 3 P1 -3 P0 (492GHz) and 3 P2 -3 P1 (809 GHz), of atomic carbon. A superconductor-insulator-superconductor (SIS) mixer receiver was equipped on the Nasmyth focus of the telescope. The receiver noise temperatures [Trx(DSB)] are 300 K and 1000 K for the 492 GHz and the 809 GHz mixers, respectively. The intermediate frequency is centered at 2 GHz, having a 700 MHz bandwidth. An acousto-optical spectrometer (AOS) with 1024 channel outputs is used as a receiver backend. The telescope was installed at Nishi-yasugawara (alt. 3725 m), which is 200 m north of the highest peak, Kengamine (3776 m), in July 1998. It has b en operatede successfully during 4 observing seasons in a remote way from the Hongo campus of the University of Tokyo. We have already observed more than 40 square degrees of the sky with the CI 492 GHz line. The distribution of CI emission is found to be different from those of the 13 CO or C1 8 O emission in some clouds. These differences are discussed in relation to formation processes of molecular clouds.

  6. Transition-Edge Hot-Electron Microbolometers for Millimeter and Submillimeter Astrophysics

    Science.gov (United States)

    Hsieh, Wen-Ting; Stevenson, Thomas; U-yen, Kongpop; Wollack, Edward; Barrentine, Emily

    2014-01-01

    The millimeter and the submillimeter wavelengths of the electromagnetic spectrum hold a wealth of information about the evolution of the universe. In particular, cosmic microwave background (CMB) radiation and its polarization carry the oldest information in the universe, and provide the best test of the inflationary paradigm available to astronomy today. Detecting gravity waves through their imprint on the CMB polarization would have extraordinary repercussions for cosmology and physics. A transition-edge hot-electron micro - bolometer (THM) consists of a superconducting bilayer transition-edge sensor (TES) with a thin-film absorber. Unlike traditional monolithic bolometers that make use of micromachined structures, the THM em ploys the decoupling between electrons and phonons at millikelvin temperatures to provide thermal isolation. The devices are fabricated photolithographically and are easily integrated with antennas via microstrip transmission lines, and with SQUID (superconducting quantum interference device) readouts. The small volume of the absorber and TES produces a short thermal time constant that facilitates rapid sky scanning. The THM consists of a thin-film metal absorber overlapping a superconducting TES. The absorber forms the termination of a superconducting microstripline that carries RF power from an antenna. The purpose of forming a separate absorber and TES is to allow flexibility in the optimization of the two components. In particular, the absorbing film's impedance can be chosen to match the antenna, while the TES impedance can be chosen to match to the readout SQUID amplifier. This scheme combines the advantages of the TES with the advantages of planar millimeter-wave transmission line circuits. Antenna-coupling to the detectors via planar transmission lines allows the detector dimensions to be much smaller than a wavelength, so the technique can be extended across the entire microwave, millimeter, and submillimeter wavelength ranges. The

  7. A New Era of Submillimeter GRB Afterglow Follow-Ups with the Greenland Telescope

    Directory of Open Access Journals (Sweden)

    Yuji Urata

    2015-01-01

    Full Text Available Planned rapid submillimeter (submm gamma-ray-bursts (GRBs follow-up observations conducted using the Greenland Telescope (GLT are presented. The GLT is a 12-m submm telescope to be located at the top of the Greenland ice sheet, where the high altitude and dry weather porvide excellent conditions for observations at submm wavelengths. With its combination of wavelength window and rapid responding system, the GLT will explore new insights on GRBs. Summarizing the current achievements of submm GRB follow-ups, we identify the following three scientific goals regarding GRBs: (1 systematic detection of bright submm emissions originating from reverse shock (RS in the early afterglow phase, (2 characterization of forward shock and RS emissions by capturing their peak flux and frequencies and performing continuous monitoring, and (3 detections of GRBs at a high redshift as a result of the explosion of first generation stars through systematic rapid follow-ups. The light curves and spectra calculated by available theoretical models clearly show that the GLT could play a crucial role in these studies.

  8. Linewidth of submillimeter wave flux-flow oscillators

    DEFF Research Database (Denmark)

    Koshelets, V.P.; Shitov, S.V.; Shchukin, A.V.

    1996-01-01

    A reliable technique for wide band measurements of the spectral linewidth of superconducting oscillators integrated on-chip with superconductor-insulator-superconductor (SIS) detectors has been, developed, The spectral linewidth of flux-flow oscillators (FFO) based on the unidirectional and visco...... reference source has been demonstrated. The proposed technique may improve the sensitivity, frequency resolution, and stability of the fully superconducting integrated submillimeter wave receiver. (C) 1996 American Institute of Physics....

  9. Passive magnetic shielding for the submillimeter and far infrared experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Koji; Warner, B.A.; Di Pirro, M.J.; Numazawa, Takenori

    2003-05-01

    Goddard Space Flight Center is developing the submillimeter and far infrared experiment (SAFIRE). SAFIRE will use SQUIDs as amplifiers for detectors, which must be shielded from the magnet cooling system, an adiabatic demagnetization refrigerator (ADR). The magnetic field at the detector package must remain at or below the 10{sup -7} tesla level while the detectors are operating. We discuss laboratory tests of the passive shielding and simulations.

  10. Analysis of the Sub-Millimeter Rotational Spectrum of Urea

    Science.gov (United States)

    Thomas, Jessica R.; Fosnight, Alyssa M.; Medvedev, Ivan R.

    2013-06-01

    Urea, ((NH_{2})_{2}CO), has broad presence in biological species. As a byproduct of human metabolism, this molecule is commonly tested for in blood to diagnose different pathologies. Furthermore, urea is seen in interstellar medium and its detection could yield valuable insight into the mechanisms governing star formation. Despite the prevalence of urea, an absence exists in recorded frequencies of this molecule. The new generation of the sub-millimeter telescopes, such as ALMA, HERSCHEL, and SOFIA, allows detection of interstellar molecular spectra at unprecedented spatial and spectral resolutions. The knowledge of the precise frequencies of spectra transitions present in interstellar molecular clouds would alleviate the problem of spectral congestion and aid in molecular identification. This paper reports the most recent investigation of the submillimeter/terahertz gas phase spectrum of urea. Up until now, only the microwave laboratory spectrum of urea's vibrational ground state has been available. This paper reports the high-resolution spectra of urea in the sub-millimeter range, and extends the spectroscopic assignment of the rotational transitions in the vibrational ground state. Additionally, the assignment of the first vibrational state and tentative assignments of two additional vibrational states have been made.

  11. A SUBMILLIMETER CONTINUUM SURVEY OF LOCAL DUST-OBSCURED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Chul [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055 (Korea, Republic of); Hwang, Ho Seong [School of Physics, Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 02455 (Korea, Republic of); Lee, Gwang-Ho, E-mail: jclee@kasi.re.kr [Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of)

    2016-12-20

    We conduct a 350 μ m dust continuum emission survey of 17 dust-obscured galaxies (DOGs) at z = 0.05–0.08 with the Caltech Submillimeter Observatory (CSO). We detect 14 DOGs with S{sub 350μm} = 114–650 mJy and signal-to-noise > 3. By including two additional DOGs with submillimeter data in the literature, we are able to study dust content for a sample of 16 local DOGs, which consist of 12 bump and four power-law types. We determine their physical parameters with a two-component modified blackbody function model. The derived dust temperatures are in the range 57–122 K and 22–35 K for the warm and cold dust components, respectively. The total dust mass and the mass fraction of the warm dust component are 3–34 × 10{sup 7} M {sub ⊙} and 0.03%–2.52%, respectively. We compare these results with those of other submillimeter-detected infrared luminous galaxies. The bump DOGs, the majority of the DOG sample, show similar distributions of dust temperatures and total dust mass to the comparison sample. The power-law DOGs show a hint of smaller dust masses than other samples, but need to be tested with a larger sample. These findings support that the reason DOGs show heavy dust obscuration is not an overall amount of dust content, but probably the spatial distribution of dust therein.

  12. Planar Lenses at Visible Wavelengths

    CERN Document Server

    Khorasaninejad, Mohammadreza; Devlin, Robert C; Oh, Jaewon; Zhu, Alexander Y; Capasso, Federico

    2016-01-01

    Sub-wavelength resolution imaging requires high numerical aperture (NA) lenses, which are bulky and expensive. Metasurfaces allow the miniaturization of conventional refractive optics into planar structures. We show that high-aspect-ratio titanium dioxide metasurfaces can be fabricated and designed as meta-lenses with NA = 0.8. Diffraction-limited focusing is demonstrated at wavelengths of 405 nm, 532 nm, and 660 nm with corresponding efficiencies of 86%, 73%, and 66%. The meta-lenses can resolve nanoscale features separated by sub-wavelength distances and provide magnification as high as 170x with image qualities comparable to a state-of-the-art commercial objective. Our results firmly establish that meta-lenses can have widespread applications in laser-based microscopy, imaging, and spectroscopy.

  13. Research Status and Action of Sub-millimeter Debris Impact Damage on Spacecraft Structure

    OpenAIRE

    Higashide, Masumi; Kurosaki, Hirohisa; Hasegawa, Sunao; 東出, 真澄; 黒崎, 裕久; 長谷川, 直

    2015-01-01

    To assess debris impact risk for the satellite, submillimeter debris impact damage has not been investigated enough to conduct satellite protective designing. JAXA is researching vulnerability of satellite structure materials against submillimeter debris impact, and proposing shielding methods. This report shows summary of submillimeter impact damages of honeycomb sandwich panels. The damage of the panel was investigated by hypervelocity impact experiments with the two-stage light gas gun in ...

  14. MEASURING MASS ACCRETION RATE ONTO THE SUPERMASSIVE BLACK HOLE IN M87 USING FARADAY ROTATION MEASURE WITH THE SUBMILLIMETER ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, C. Y.; Asada, K.; Rao, R.; Nakamura, M.; Algaba, J. C.; Liu, H. B.; Inoue, M.; Koch, P. M.; Ho, P. T. P.; Matsushita, S.; Pu, H.-Y.; Nishioka, H.; Pradel, N. [Academia Sinica, Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Akiyama, K. [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)

    2014-03-10

    We present the first constraint on the Faraday rotation measure (RM) at submillimeter wavelengths for the nucleus of M87. By fitting the polarization position angles (χ) observed with the Submillimeter Array at four independent frequencies around ∼230 GHz and interpreting the change in χ as a result of external Faraday rotation associated with accretion flow, we determine the RM of the M87 core to be between –7.5 × 10{sup 5} and 3.4 × 10{sup 5} rad m{sup –2}. Assuming a density profile of the accretion flow that follows a power-law distribution and a magnetic field that is ordered, radial, and has equipartition strength, the limit on the RM constrains the mass accretion rate M-dot to be below 9.2 × 10{sup –4} M {sub ☉} yr{sup –1} at a distance of 21 Schwarzschild radii from the central black hole. This value is at least two orders of magnitude smaller than the Bondi accretion rate, suggesting significant suppression of the accretion rate in the inner region of the accretion flow. Consequently, our result disfavors the classical advection-dominated accretion flow and prefers the adiabatic inflow-outflow solution or convection-dominated accretion flow for the hot accretion flow in M87.

  15. Synthetic 3D modeling of active regions and simulation of their multi-wavelength emission

    Science.gov (United States)

    Nita, Gelu M.; Fleishman, Gregory; Kuznetsov, Alexey A.; Loukitcheva, Maria A.; Viall, Nicholeen M.; Klimchuk, James A.; Gary, Dale E.

    2015-04-01

    To facilitate the study of solar active regions, we have created a synthetic modeling framework that combines 3D magnetic structures obtained from magnetic extrapolations with simplified 1D thermal models of the chromosphere, transition region, and corona. To handle, visualize, and use such synthetic data cubes to compute multi-wavelength emission maps and compare them with observations, we have undertaken a major enhancement of our simulation tools, GX_Simulator (ftp://sohoftp.nascom.nasa.gov/solarsoft/packages/gx_simulator/), developed earlier for modeling emission from flaring loops. The greatly enhanced, object-based architecture, which now runs on Windows, Mac, and UNIX platform, offers important new capabilities that include the ability to either import 3D density and temperature distribution models, or to assign to each individual voxel numerically defined coronal or chromospheric temperature and densities, or coronal Differential Emission Measure distributions. Due to these new capabilities, the GX_Simulator can now apply parametric heating models involving average properties of the magnetic field lines crossing a given voxel volume, as well as compute and investigate the spatial and spectral properties of radio (to be compared with VLA or EOVSA data), (sub-)millimeter (ALMA), EUV (AIA/SDO), and X-ray (RHESSI) emission calculated from the model. The application integrates shared-object libraries containing fast free-free, gyrosynchrotron, and gyroresonance emission codes developed in FORTRAN and C++, and soft and hard X-ray and EUV codes developed in IDL. We use this tool to model and analyze an active region and compare the synthetic emission maps obtained in different wavelengths with observations.This work was partially supported by NSF grants AGS-1250374, AGS-1262772, NASA grant NNX14AC87G, the Marie Curie International Research Staff Exchange Scheme "Radiosun" (PEOPLE-2011-IRSES-295272), RFBR grants 14-02-91157, 15-02-01089, 15-02-03717, 15

  16. CLUMPY AND EXTENDED STARBURSTS IN THE BRIGHTEST UNLENSED SUBMILLIMETER GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Iono, Daisuke; Hatsukade, Bunyo; Kawabe, Ryohei; Matsuda, Yuichi; Nakanishi, Kouichiro [National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Yun, Min S.; Wilson, Grant [University of Massachusetts, Department of Astronomy, 710 North Pleasant Street, Amherst, MA 01003 (United States); Aretxaga, Itziar; Hughes, David [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Luis Enrique Erro 1, Sta. Ma. Tonantzintla, Puebla (Mexico); Ikarashi, Soh [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700AV Groningen (Netherlands); Izumi, Takuma; Kohno, Kotaro; Tamura, Yoichi; Umehata, Hideki [Institute of Astronomy, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Lee, Minju; Saito, Toshiki [Department of Astronomy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 133-0033 (Japan); Ueda, Junko [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Michiyama, Tomonari; Ando, Misaki, E-mail: d.iono@nao.ac.jp [SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2016-09-20

    The central structure in three of the brightest unlensed z = 3–4 submillimeter galaxies is investigated through 0.″015–0.″05 (120–360 pc) 860 μ m continuum images obtained using the Atacama Large Millimeter/submillimeter Array (ALMA). The distribution in the central kiloparsec in AzTEC1 and AzTEC8 is extremely complex, and they are composed of multiple ∼200 pc clumps. AzTEC4 consists of two sources that are separated by ∼1.5 kpc, indicating a mid-stage merger. The peak star formation rate densities in the central clumps are ∼300–3000 M {sub ⊙} yr{sup −1} kpc{sup −2}, suggesting regions with extreme star formation near the Eddington limit. By comparing the flux obtained by ALMA and Submillimeter Array, we find that 68%–90% of the emission is extended (≳1 kpc) in AzTEC4 and 8. For AzTEC1, we identify at least 11 additional compact (∼200 pc) clumps in the extended 3–4 kpc region. Overall, the data presented here suggest that the luminosity surface densities observed at ≲150 pc scales are roughly similar to that observed in local ULIRGs, as in the eastern nucleus of Arp 220. Between 10% and 30% of the 860 μ m continuum is concentrated in clumpy structures in the central kiloparsec, while the remaining flux is distributed over ≳1 kpc regions, some of which could also be clumpy. These sources can be explained by a rapid inflow of gas such as a merger of gas-rich galaxies, surrounded by extended and clumpy starbursts. However, the cold mode accretion model is not ruled out.

  17. Micro-Spec: An Ultracompact, High-sensitivity Spectrometer for Far-Infrared and Submillimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe; Hsieh, Wen-Ting; Huang, Wei-Chung; Moseley, S. Harvey; Stevenson, Thomas R.; Wollack, Edward J.

    2014-01-01

    High-performance, integrated spectrometers operating in the far-infrared and submillimeter ranges promise to be powerful tools for the exploration of the epochs of reionization and initial galaxy formation. These devices, using high-efficiency superconducting transmission lines, can achieve the performance of a meter-scale grating spectrometer in an instrument implemented on a 4 inch silicon wafer. Such a device, when combined with a cryogenic telescope in space, provides an enabling capability for studies of the early universe. Here, the optical design process for Micro-Spec (micron-Spec) is presented, with particular attention given to its two-dimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the stigmatization and minimization of the light path function in this bounded region, which results in an optimized geometrical configuration. A point design with an efficiency of (is) approximately 90% has been developed for initial demonstration and can serve as the basis for future instruments. Design variations on this implementation are also discussed, which can lead to lower efficiencies due to diffractive losses in the multimode region.

  18. Submillimeter Measurements of Photolysis Products in Interstellar Ice Analogs: A New Experimental Technique

    Science.gov (United States)

    Milam, Stefanie N.; Weaver, Susanna Widicus

    2012-01-01

    Over 150 molecular species have been confirmed in space, primarily by their rotational spectra at millimeter/submillimeter wavelengths, which yield an unambiguous identification. Many of the known interstellar organic molecules cannot be explained by gas-phase chemistry. It is now presumed that they are produced by surface reactions of the simple ices and/or grains observed and released into the gas phase by sublimation, sputtering, etc. Additionally, the chemical complexity found in meteorites and samples returned from comets far surpasses that of the remote detections for the interstellar medium (ISM), comets, and planetary atmospheres. Laboratory simulations of interstellar/cometary ices have found, from the analysis of the remnant residue of the warmed laboratory sample, that such molecules are readily formed; however, it has yet to be determined if they are formed during the warm phase or within the ice during processing. Most analysis of the ice during processing reveals molecular changes, though the exact quantities and species formed are highly uncertain with current techniques due to overwhelming features of simple ices. Remote sensing with high resolution spectroscopy is currently the only method to detect trace species in the ISM and the primary method for comets and icy bodies in the Solar System due to limitations of sample return. We have recently designed an experiment to simulate interstellar/cometary/planetary ices and detect trace species employing the same techniques used for remote observations. Preliminary results will be presented.

  19. The SOFIA/SAFIRE Far-Infrared Spectrometer: Highlighting Submillimeter Astrophysics and Technology

    Science.gov (United States)

    Benford, Dominic J.

    2009-01-01

    The Submillimeter and Far-InfraRed Experiment (SAFIRE) on the SOFIA airborne observatory is an imaging spectrometer for wavelengths between 28 microns and 440 microns. Our design is a dual-band long-slit grating spectrometer, which provides broadband (approx. 4000 km/s) observations in two lines simultaneously over a field of view roughly 10" wide by 320" long. The low backgrounds in spectroscopy require very sensitive detectors with noise equivalent powers of order 10(exp -18) W/square root of Hz. We are developing a kilopixel, filled detector array for SAFIRE in a 32 x 40 format. The detector consists of a transition edge sensor (TES) bolometer array, a per-pixel broadband absorbing backshort array, and a NIST SQUID multiplexer readout array. This general type of array has been used successfully in the GISMO instrument, so we extrapolate to the sensitivity needed for airborne spectroscopy. Much of the cryogenic, electronics, and software infrastructure for SAFIRE have been developed. I provide here an overview of the progress on SAFIRE.

  20. Millimeter and Submillimeter Observations of Comet 67P's Nucleus, Gas, and Dust with the Rosetta/MIRO Instrument

    Science.gov (United States)

    Hofstadter, Mark

    2016-04-01

    The Microwave Instrument for the Rosetta Orbiter (MIRO) has been making measurements of comet 67P/C-G since June 2014, when the comet was 3.92 AU from the Sun and Rosetta was approximately 400,000 km from the nucleus. Those first observations were spatially unresolved measurements of the 556 GHz water line, used to infer the abundance and velocity of water vapor in the coma (Gulkis et al. 2015, Science 347). In the almost two years since that time, as the spacecraft has moved closer to the nucleus and the comet has become more active (perihelion at 1.2 AU from the Sun occurred in August 2015), MIRO's submillimeter spectrometer (working at frequencies near 550 GHz, or wavelengths near 0.5 mm) has been used to determine the velocity, abundance, and spatial distribution of H216O, H217O, H218O, CH3OH, NH3, and CO in the coma as a function of time (e.g. water is discussed by Biver et al. 2015 and Lee et al. 2015, Astron. and Astrophys. 583). In addition to its submillimeter spectrometer, MIRO has two broad band continuum channels operating at wavelengths near 0.5 and 1.6 millimeter. These channels are designed to probe the nucleus ˜1 millimeter to 10 cm below the surface. Data have been used to infer properties such as thermal inertia, porosity, and ice content as functions of location, depth, and time (e.g. Schloerb et al. 2015 and Choukroun et al. 2015, Astron. and Astrophys. 583). These channels have also been used to map the distribution of relatively large dust grains (radius > ˜1 mm) in the inner coma of the comet, with the potential to constrain models of dust acceleration, cooling, and fragmentation. This talk will review the latest results from MIRO's measurements of the nucleus, coma, and dust, and discuss some of the processes that couple these components of the comet.

  1. A polarizing Fourier Transform Spectrometer to characterize millimeter-wavelength filters and measure the atmospheric opacity

    Science.gov (United States)

    Ferrusca, D.; Velázquez de La Rosa, M.; Hughes, D. H.; Devlin, M.; Swetz, D.

    2005-12-01

    We will shortly complete the testing of a cryogenic (1.8K) total-power sky monitor which will measure the temporal fluctuations of the sky brightness at millimeter wavelengths. In this article we outline the development of a polarizing Fourier Transform Spectrometer (FTS) that can characterize the spectral response of our mm-wavelength filters and entire optical system. Since the FTS will be portable, we can also measure the seasonal changes in the atmospheric transmission windows above Sierra Negra (the GTM site). These data will influence the design of submillimeter and millimeter filters for future GTM instruments.

  2. Micro-Spec: an Integrated, Direct-Detection Spectrometer for Far-Infrared and Submillimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe

    2014-01-01

    The far-infrared and submillimeter portions of the electromagnetic spectrum provide a unique view of the astrophysical processes present in the early universe. Our ability to fully explore this rich spectral region has been limited, however, by the size and cost of the cryogenic spectrometers required to carry out such measurements. Micro-Spec (u-Spec) is a high-sensitivity, direct-detection spectrometer concept working in the 450-1000 micromillimeter wavelength range which will enable a wide range of flight missions that would otherwise be challenging due to the large size of current instruments with the required spectral resolution and sensitivity. The spectrometer design utilizes two internal antenna arrays, one for transmitting and one for receiving, superconducting microstrip transmission lines for power division and phase delay, and an array of microwave kinetic inductance detectors (MKIDs) to achieve these goals. The instrument will be integrated on a approximately 10 square cm silicon chip and can therefore become an important capability under the low background conditions accessible via space and high-altitude borne platforms. In this paper, an optical design methodology for Micro-Spec is presented, with particular attention given to its twodimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the maximization of the instrument resolving power and minimization of the RMS phase error on the instrument focal plane. This two-step optimization can generate geometrical configurations given specific requirements on spectrometer size, operating spectral range and performance. A point design with resolving power of 257, an RMS phase error less than 0.1 radians and four stigmatic points was developed for initial demonstration and will be the basis of future instruments with resolving power up to about 1200.

  3. Properties of Submillimeter Galaxies in the CANDELS GOODS-South Field

    NARCIS (Netherlands)

    Wiklind, Tommy; Conselice, Christopher J.; Dahlen, Tomas; Dickinson, Mark E.; Ferguson, Henry C.; Grogin, Norman A.; Guo, Yicheng; Koekemoer, Anton M.; Mobasher, Bahram; Mortlock, Alice; Fontana, Adriano; Davé, Romeel; Yan, Haojing; Acquaviva, Viviana; Ashby, Matthew L. N.; Barro, Guillermo; Caputi, Karina I.; Castellano, Marco; Dekel, Avishai; Donley, Jennifer L.; Fazio, Giovanni G.; Giavalisco, Mauro; Grazian, Andrea; Hathi, Nimish P.; Kurczynski, Peter; Lu, Yu; McGrath, Elizabeth J.; de Mello, Duilia F.; Peth, Michael; Safarzadeh, Mohammad; Stefanon, Mauro; Targett, Thomas

    We derive physical properties of 10 submillimeter galaxies located in the CANDELS coverage of the GOODS-S field. The galaxies were first identified as submillimeter sources with the LABOCA bolometer and subsequently targeted for 870 μm continuum observation with ALMA. The high angular resolution of

  4. InP HEMT Integrated Circuits for Submillimeter Wave Radiometers in Earth Remote Sensing

    Science.gov (United States)

    Deal, William R.; Chattopadhyay, Goutam

    2012-01-01

    The operating frequency of InP integrated circuits has pushed well into the Submillimeter Wave frequency band, with amplification reported as high as 670 GHz. This paper provides an overview of current performance and potential application of InP HEMT to Submillimeter Wave radiometers for earth remote sensing.

  5. A Sub-millimeter, Inductively Powered Neural Stimulator

    Directory of Open Access Journals (Sweden)

    Daniel K. Freeman

    2017-11-01

    Full Text Available Wireless neural stimulators are being developed to address problems associated with traditional lead-based implants. However, designing wireless stimulators on the sub-millimeter scale (<1 mm3 is challenging. As device size shrinks, it becomes difficult to deliver sufficient wireless power to operate the device. Here, we present a sub-millimeter, inductively powered neural stimulator consisting only of a coil to receive power, a capacitor to tune the resonant frequency of the receiver, and a diode to rectify the radio-frequency signal to produce neural excitation. By replacing any complex receiver circuitry with a simple rectifier, we have reduced the required voltage levels that are needed to operate the device from 0.5 to 1 V (e.g., for CMOS to ~0.25–0.5 V. This reduced voltage allows the use of smaller receive antennas for power, resulting in a device volume of 0.3–0.5 mm3. The device was encapsulated in epoxy, and successfully passed accelerated lifetime tests in 80°C saline for 2 weeks. We demonstrate a basic proof-of-concept using stimulation with tens of microamps of current delivered to the sciatic nerve in rat to produce a motor response.

  6. An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South : Source Catalog and Multiplicity

    NARCIS (Netherlands)

    Hodge, J.; Karim, A.; Smail, I.; Swinbank, A.; Walter, F.; Biggs, A.; Ivison, R.; Weiss, A.; Alexander, D.; Bertoldi, F.; Brandt, W.; Chapman, S.; Coppin, K.; Cox, P.; Danielson, A.; Dannerbauer, H.; De, Breuck C.; Decarli, R.; Edge, A.; Greve, T.; Knudsen, K.; Menten, K.; Rix, H.; Schinnerer, E.; Simpson, J.; Wardlow, J.; Werf, van der P.P.

    2013-01-01

    We present an Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 0 survey of 126 submillimeter sources from the LABOCA ECDFS Submillimeter Survey (LESS). Our 870 {$μ$}m survey with ALMA (ALESS) has produced maps ~{}3{ imes} deeper and with a beam area ~{}200{ imes} smaller than the original

  7. INFRARED AND RADIO OBSERVATIONS OF A SMALL GROUP OF PROTOSTELLAR OBJECTS IN THE MOLECULAR CORE, L1251-C

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jungha; Lee, Jeong-Eun [School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Choi, Minho; Kang, Miju [Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of); Bourke, Tyler L. [Square Kilometre Array Organisation, Jodrell Bank Observatory, Lower Withington, Cheshire SK11 9DL (United Kingdom); II, Neal J. Evans [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Francesco, James Di [National Research Council Canada, Herzberg Institute of Astrophysics, Victoria, BC (Canada); Cieza, Lucas A. [Universidad Diego Portales, Facultad de Ingeniera, Av. Ejército 441, Santiago (Chile); Dunham, Michael M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-05-15

    We present a multi-wavelength observational study of a low-mass star-forming region, L1251-C, with observational results at wavelengths from the near-infrared to the millimeter. Spitzer Space Telescope observations confirmed that IRAS 22343+7501 is a small group of protostellar objects. The extended emission in the east–west direction with its intensity peak at the center of L1251A has been detected at 350 and 850 μm with the Caltech Submillimeter Observatory and James Clerk Maxwell telescopes, tracing dense envelope material around L1251A. The single-dish data from the Korean VLBI Network and TRAO telescopes show inconsistencies between the intensity peaks of several molecular emission lines and that of the continuum emission, suggesting complex distributions of molecular abundances around L1251A. The Submillimeter Array interferometer data, however, show intensity peaks of CO 2–1 and {sup 13}CO 2–1 located at the position of IRS 1, which is both the brightest source in the Infrared Array Camera image and the weakest source in the 1.3 mm dust-continuum map. IRS 1 is the strongest candidate for the driving source of the newly detected compact CO 2–1 outflow. Over the entire region (14′ × 14′) of L125l-C, 3 Class I and 16 Class II sources have been detected, including three young stellar objects (YSOs) in L1251A. A comparison between the average projected distance among the 19 YSOs in L1251-C and that among the 3 YSOs in L1251A suggests that L1251-C is an example of low-mass cluster formation where protostellar objects form in a small group.

  8. Short wavelength FELS

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, R.L.

    1991-01-01

    The generation of coherent ultraviolet and shorter wavelength light is presently limited to synchrotron sources. The recent progress in the development of brighter electron beams enables the use of much lower energy electron rf linacs to reach short-wavelengths than previously considered possible. This paper will summarize the present results obtained with synchrotron sources, review proposed short- wavelength FEL designs and then present a new design which is capable of over an order of magnitude higher power to the extreme ultraviolet. 17 refs., 10 figs.

  9. Compact Receiver Front Ends for Submillimeter-Wave Applications

    Science.gov (United States)

    Mehdi, Imran; Chattopadhyay, Goutam; Schlecht, Erich T.; Lin, Robert H.; Sin, Seth; Peralta, Alejandro; Lee, Choonsup; Gill, John J.; Gulkis, Samuel; Thomas, Bertrand C.

    2012-01-01

    The current generation of submillimeter-wave instruments is relatively mass and power-hungry. The receiver front ends (RFEs) of a submillimeter instrument form the heart of the instrument, and any mass reduction achieved in this subsystem is propagated through the instrument. In the current implementation, the RFE consists of different blocks for the mixer and LO circuits. The motivation for this work is to reduce the mass of the RFE by integrating the mixer and LO circuits in one waveguide block. The mixer and its associated LO chips will all be packaged in a single waveguide package. This will reduce the mass of the RFE and also provide a number of other advantages. By bringing the mixer and LO circuits close together, losses in the waveguide will be reduced. Moreover, the compact nature of the block will allow for better thermal control of the block, which is important in order to reduce gain fluctuations. A single waveguide block with a 600- GHz RFE functionality (based on a subharmonically pumped Schottky diode pair) has been demonstrated. The block is about 3x3x3 cubic centimeters. The block combines the mixer and multiplier chip in a single package. 3D electromagnetic simulations were carried out to design the waveguide circuit around the mixer and multiplier chip. The circuit is optimized to provide maximum output power and maximum bandwidth. An integrated submillimeter front end featuring a 520-600-GHz sub-harmonic mixer and a 260-300-GHz frequency tripler in a single cavity was tested. Both devices used GaAs MMIC membrane planar Schottky diode technology. The sub-harmonic mixer/tripler circuit has been tested using conventional metal-machined blocks. Measurement results on the metal block give best DSB (double sideband) mixer noise temperature of 2,360 K and conversion losses of 7.7 dB at 520 GHz. The LO input power required to pump the integrated tripler/sub-harmonic mixer is between 30 and 50 mW.

  10. Multipass millimeter/submillimeter spectrometer to probe dissociative reaction dynamics.

    Science.gov (United States)

    Laas, Jacob C; Hays, Brian M; Widicus Weaver, Susanna L

    2013-10-03

    We present here the instrument design and first experimental results from a multipass millimeter/submillimeter spectrometer designed to probe dissociative reaction dynamics. This work focuses on benchmarking the instrument performance through detection of the CH3O and H2CO products from methanol dissociation induced by a high-voltage plasma discharge. Multiple rotational lines from CH3O and H2CO were observed when this plasma discharge was applied to a sample of methanol vapor seeded in an argon supersonic expansion. The rotational temperature of the dissociation products and their abundance with respect to methanol were determined using a Boltzmann analysis. The minimum detectable absorption coefficient for this instrument was determined to be αmin ≤ 5 × 10(-9) cm(-1). We discuss these results in the context of future applications of this instrument to the study of photodissociation branching ratios for small organic molecules that are important in complex interstellar chemistry.

  11. The role of THz and submillimeter wave technology in DHS

    Science.gov (United States)

    Coty, Thomas; Fuller-Tedeschi, Anna

    2011-06-01

    THz and submillimeter wave technology is of great interest to DHS S&T due to the non-ionizing and clothing penetrating properties of the spectral region. Imaging in the region allows for standoff imaging of concealed threats such as Improvised Explosive Devices (IED) at operationally relevant distances. DHS S&T is investing in this area with the development of components such as detectors and sources for active imaging as well as full sensor systems in the future. The fundamental characterization of the region is also being explored with DHS funding by imaging well-characterized rough surface scattering targets. Analysis of these images will yield data to be used in evaluating assumptions currently made in current performance models. This along with the relevant field applications will be addressed.

  12. Status of MUSIC, the MUltiwavelength Sub/millimeter Inductance Camera

    Science.gov (United States)

    Golwala, Sunil R.; Bockstiegel, Clint; Brugger, Spencer; Czakon, Nicole G.; Day, Peter K.; Downes, Thomas P.; Duan, Ran; Gao, Jiansong; Gill, Amandeep K.; Glenn, Jason; Hollister, Matthew I.; LeDuc, Henry G.; Maloney, Philip R.; Mazin, Benjamin A.; McHugh, Sean G.; Miller, David; Noroozian, Omid; Nguyen, Hien T.; Sayers, Jack; Schlaerth, James A.; Siegel, Seth; Vayonakis, Anastasios K.; Wilson, Philip R.; Zmuidzinas, Jonas

    2012-09-01

    We present the status of MUSIC, the MUltiwavelength Sub/millimeter Inductance Camera, a new instrument for the Caltech Submillimeter Observatory. MUSIC is designed to have a 14', diffraction-limited field-of-view instrumented with 2304 detectors in 576 spatial pixels and four spectral bands at 0.87, 1.04, 1.33, and 1.98 mm. MUSIC will be used to study dusty star-forming galaxies, galaxy clusters via the Sunyaev-Zeldovich effect, and star formation in our own and nearby galaxies. MUSIC uses broadband superconducting phased-array slot-dipole antennas to form beams, lumpedelement on-chip bandpass filters to define spectral bands, and microwave kinetic inductance detectors to sense incoming light. The focal plane is fabricated in 8 tiles consisting of 72 spatial pixels each. It is coupled to the telescope via an ambient-temperature ellipsoidal mirror and a cold reimaging lens. A cold Lyot stop sits at the image of the primary mirror formed by the ellipsoidal mirror. Dielectric and metal-mesh filters are used to block thermal infrared and out-ofband radiation. The instrument uses a pulse tube cooler and 3He/ 3He/4He closed-cycle cooler to cool the focal plane to below 250 mK. A multilayer shield attenuates Earth's magnetic field. Each focal plane tile is read out by a single pair of coaxes and a HEMT amplifier. The readout system consists of 16 copies of custom-designed ADC/DAC and IF boards coupled to the CASPER ROACH platform. We focus on recent updates on the instrument design and results from the commissioning of the full camera in 2012.

  13. Submillimeter observations of the sun from the James Clerk Maxwell Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Lindsey, C.A.; Yee, S.; Roellig, T.L.; Hills, R.; Brock, D. (Hawaii Univ., Honolulu (USA) NASA, Ames Research Center, Moffett Field, CA (USA) Mullard Radio Astronomy Observatory, Cambridge (England) Joint Astronomy Centre, Hilo, HI (USA))

    1990-04-01

    The first submillimeter solar observations from the 15 m James Clerk Maxwell Telescope (JCMT) on Mauna Kea are reported. The JCMT submillimeter heterodyne receiver is used to observe the sun in 850 micron radiation. These are the first submillimeter observations of features on the size scale of the chromospheric supergranular network and of sunspots. A comparison is made between 850 micron images and calcium K line images of the chromospheric supergranular network in the quiet sun and in plage. Images of sunspots are given, noting that their 850 micron brightness is comparable to, or somewhat greater than, that of the quiet sun. 7 refs.

  14. Submillimeter observations of the sun from the James Clerk Maxwell Telescope

    Science.gov (United States)

    Lindsey, Charles A.; Yee, Selwyn; Roellig, Thomas L.; Hills, Richard; Brock, David

    1990-01-01

    The first submillimeter solar observations from the 15 m James Clerk Maxwell Telescope (JCMT) on Mauna Kea are reported. The JCMT submillimeter heterodyne receiver is used to observe the sun in 850 micron radiation. These are the first submillimeter observations of features on the size scale of the chromospheric supergranular network and of sunspots. A comparison is made between 850 micron images and calcium K line images of the chromospheric supergranular network in the quiet sun and in plage. Images of sunspots are given, noting that their 850 micron brightness is comparable to, or somewhat greater than, that of the quiet sun.

  15. TIMASSS: the IRAS 16293-2422 millimeter and submillimeter spectral survey. I. Observations, calibration, and analysis of the line kinematics

    Science.gov (United States)

    Caux, E.; Kahane, C.; Castets, A.; Coutens, A.; Ceccarelli, C.; Bacmann, A.; Bisschop, S.; Bottinelli, S.; Comito, C.; Helmich, F. P.; Lefloch, B.; Parise, B.; Schilke, P.; Tielens, A. G. G. M.; van Dishoeck, E.; Vastel, C.; Wakelam, V.; Walters, A.

    2011-08-01

    Context. Unbiased spectral surveys are powerful tools to study the chemistry and the physics of star forming regions, because they can provide a complete census of the molecular content and the observed lines probe the physical structure of the source. Aims: While unbiased surveys at the millimeter and sub-millimeter wavelengths observable from ground-based telescopes have previously been performed towards several high mass protostars, very little exists on low mass protostars, which are believed to resemble our own Sun's progenitor. To help fill up this gap in our understanding, we carried out a complete spectral survey of the bands at 3, 2, 1, and 0.9 mm towards the solar type protostar IRAS 16293-2422. Methods: The observations covered a range of about 200 GHz and were obtained with the IRAM-30 m and JCMT-15 m telescopes during about 300 h of observations. Particular attention was devoted to the inter-calibration of the acquired spectra with previous observations. All the lines detected with more than 3σ confidence-interval certainty and free from obvious blending effects were fitted with Gaussians to estimate their basic kinematic properties. Results: More than 4000 lines were detected (with σ ≥ 3) and identified, yielding a line density of approximatively 20 lines per GHz, comparable to previous surveys in massive hot cores. The vast majority (about two-thirds) of the lines are weak and produced by complex organic molecules. The analysis of the profiles of more than 1000 lines belonging to 70 species firmly establishes the presence of two distinct velocity components associated with the two objects, A and B, forming the IRAS 16293-2422 binary system. In the source A, the line widths of several species increase with the upper level energy of the transition, a behavior compatible with gas infalling towards a ~1 M⊙ object. The source B, which does not show this effect, might have a much lower central mass of ~0.1 M⊙. The difference in the rest velocities

  16. YOUNG STELLAR OBJECTS IN THE GOULD BELT

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, Michael M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 78, Cambridge, MA 02138 (United States); Allen, Lori E. [National Optical Astronomy Observatories, Tucson, AZ (United States); Evans II, Neal J.; Harvey, Paul M. [Department of Astronomy, The University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Broekhoven-Fiene, Hannah [Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8W 3P6 (Canada); Cieza, Lucas A. [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile); Di Francesco, James; Johnstone, Doug; Matthews, Brenda C. [National Research Council of Canada, Herzberg Astronomy and Astrophysics Programs, 5071 West Saanich Road, Victoria, BC, V9E 2E7 (Canada); Gutermuth, Robert A. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Hatchell, Jennifer [Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Heiderman, Amanda [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Huard, Tracy L. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Kirk, Jason M. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE (United Kingdom); Miller, Jennifer F. [Gemini Observatory, 670 N. A’ohoku Place, Hilo, HI 96720 (United States); Peterson, Dawn E. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Young, Kaisa E., E-mail: mdunham@cfa.harvard.edu [Department of Physical Sciences, Nicholls State University, P.O. Box 2022, Thibodaux, LA 70310 (United States)

    2015-09-15

    We present the full catalog of Young Stellar Objects (YSOs) identified in the 18 molecular clouds surveyed by the Spitzer Space Telescope “cores to disks” (c2d) and “Gould Belt” (GB) Legacy surveys. Using standard techniques developed by the c2d project, we identify 3239 candidate YSOs in the 18 clouds, 2966 of which survive visual inspection and form our final catalog of YSOs in the GB. We compile extinction corrected spectral energy distributions for all 2966 YSOs and calculate and tabulate the infrared spectral index, bolometric luminosity, and bolometric temperature for each object. We find that 326 (11%), 210 (7%), 1248 (42%), and 1182 (40%) are classified as Class 0 + I, Flat-spectrum, Class II, and Class III, respectively, and show that the Class III sample suffers from an overall contamination rate by background Asymptotic Giant Branch stars between 25% and 90%. Adopting standard assumptions, we derive durations of 0.40–0.78 Myr for Class 0 + I YSOs and 0.26–0.50 Myr for Flat-spectrum YSOs, where the ranges encompass uncertainties in the adopted assumptions. Including information from (sub)millimeter wavelengths, one-third of the Class 0 + I sample is classified as Class 0, leading to durations of 0.13–0.26 Myr (Class 0) and 0.27–0.52 Myr (Class I). We revisit infrared color–color diagrams used in the literature to classify YSOs and propose minor revisions to classification boundaries in these diagrams. Finally, we show that the bolometric temperature is a poor discriminator between Class II and Class III YSOs.

  17. Metrology Arrangement for Measuring the Positions of Mirrors of a Submillimeter Telescope

    Science.gov (United States)

    Abramovici, Alex; Bartman, Randall K.

    2011-01-01

    The position of the secondary mirror of a submillimeter telescope with respect to the primary mirror needs to be known .0.03 mm in three dimensions. At the time of this reporting, no convenient, reasonably priced arrangement that offers this capability exists. The solution proposed here relies on measurement devices developed and deployed for the GeoSAR mission, and later adapted for the ISAT (Innovative Space Based Radar Antenna Technology) demonstration. The measurement arrangement consists of four metrology heads, located on an optical bench, attached to the secondary mirror. Each metrology head has a dedicated target located at the edge of the primary mirror. One laser beam, launched from the head and returned by the target, is used to measure distance. Another beam, launched from a beacon on the target, is monitored by the metrology head and generates a measurement of the target position in the plane perpendicular to the laser beam. A 100-MHz modulation is carried by a collimated laser beam. The relevant wavelength is the RF one, 3 m, divided by two, because the light carries it to the target and back. The phase change due to travel to the target and back is measured by timing the zero-crossing of the RF modulation, using a 100-MHz clock. In order to obtain good resolution, the 100-MHz modulation signal is down-converted to 1 kHz. Then, the phase change corresponding to the round-trip to the target is carried by a 1-kHz signal. Since the 100-MHz clock beats 100,000 times during one period of the 1-kHz signal, the least-significant-bit (LSB) resolution is LSB = 0.015 mm.

  18. Superconducting Resonator Spectrometer for Millimeter- and Submillimeter-Wave Astrophysics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "We propose to develop a novel ultra-compact spectrograph-on-a-chip for the submillimeter and millimeter waveband. SuperSpec uses planar lithographed superconducting...

  19. Superconducting Microwave Resonator Arrays for Submillimeter/Far-Infrared Imaging

    Science.gov (United States)

    Noroozian, Omid

    Superconducting microwave resonators have the potential to revolutionize submillimeter and far-infrared astronomy, and with it our understanding of the universe. The field of low-temperature detector technology has reached a point where extremely sensitive devices like transition-edge sensors are now capable of detecting radiation limited by the background noise of the universe. However, the size of these detector arrays are limited to only a few thousand pixels. This is because of the cost and complexity of fabricating large-scale arrays of these detectors that can reach up to 10 lithographic levels on chip, and the complicated SQUID-based multiplexing circuitry and wiring for readout of each detector. In order to make substantial progress, next-generation ground-based telescopes such as CCAT or future space telescopes require focal planes with large-scale detector arrays of 104--10 6 pixels. Arrays using microwave kinetic inductance detectors (MKID) are a potential solution. These arrays can be easily made with a single layer of superconducting metal film deposited on a silicon substrate and pattered using conventional optical lithography. Furthermore, MKIDs are inherently multiplexable in the frequency domain, allowing ˜ 10 3 detectors to be read out using a single coaxial transmission line and cryogenic amplifier, drastically reducing cost and complexity. An MKID uses the change in the microwave surface impedance of a superconducting thin-film microresonator to detect photons. Absorption of photons in the superconductor breaks Cooper pairs into quasiparticles, changing the complex surface impedance, which results in a perturbation of resonator frequency and quality factor. For excitation and readout, the resonator is weakly coupled to a transmission line. The complex amplitude of a microwave probe signal tuned on-resonance and transmitted on the feedline past the resonator is perturbed as photons are absorbed in the superconductor. The perturbation can be

  20. Wavelength conversion technology

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    1998-01-01

    Optical wavelength conversion is currently attracting much interest. This is because it enables full flexibility and eases management of WDM fibre networks. The tutorial will review existing and potential application areas. Examples of node architectures and network demonstrators that use wavelen...

  1. Free-electron masers vs. gyrotrons prospects for high-power sources at millimeter and submillimeter wavelengths

    CERN Document Server

    Thumm, M K

    2002-01-01

    The possible applications of high-power millimeter (mm) and sub-mm waves from free-electron masers (FEMs) and gyro-devices span a wide range of technologies. The plasma physics community has already taken advantage of recent advances in applying high-power mm waves generated by long pulse or continuous wave (CW) gyrotron oscillators and short pulse very high-power FEMs in the areas of RF-plasma production, heating, non-inductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as electron cyclotron resonance heating (28-170 GHz), electron cyclotron current drive , collective Thomson scattering , microwave transmission and heat-wave propagation experiments. Continuously frequency tunable FEMs could widen these fields of applications. Another important application of CW gyrotrons is industrial materials processing, e.g. sintering of high-performance functional and structural nanostructured ceramics. Sub-mm wave sources are employed in...

  2. Submillimeter Imaging of Dust Around Main Sequence Stars

    Science.gov (United States)

    Jewitt, David

    1998-01-01

    This grant was to image circumstellar dust disks surrounding main-sequence stars. The delivery of the SCUBA detector we had planned to use for this work was delayed repeatedly, leading us to undertake a majority of the observations with the UKT14 submillimeter detector at the JCMT (James Clerk Maxwell Telescope) and optical imagers and a coronagraph at the University of Hawaii 2.2-m telescope. Major findings under this grant include: (1) We discovered 5 asymmetries in the beta Pictoris regenerated dust disk. The discovery of these asymmetries was a surprise, since smearing due to Keplerian shear should eliminate most such features on timescales of a few thousand years. One exception is the "wing tilt" asymmetry, which we interpret as due to the scattering phase function of dust disk particles. From the wing tilt and a model of the phase function, we find a disk plane inclination to the line of sight of JCMT). It is possible, for instance, that the main 850 micro-m blob is merely a galaxy or other high-z source projected onto the beta Pic mid-plane.

  3. Extending the Millimeter-Submillimeter Spectrum of Protonated Formaldehyde

    Science.gov (United States)

    Roenitz, Kevin; Zou, Luyao; Widicus Weaver, Susanna L.

    2017-06-01

    Protonated formaldehyde has been detected in the interstellar medium, where it participates in the formation and destruction of methanol. The rotational spectrum for protonated formaldehyde has been previously recorded by Amano and coworkers from 120-385 GHz using a hollow cathode discharge source for ion production. Additionally, protonated formaldehyde was produced in a supersonic expansion discharge source by Duncan and coworkers, but it was detected using time-of-flight mass spectrometry. Higher frequency spectra would help to guide additional observational studies of protonated formaldehyde using instruments such as the ALMA and SOFIA observatories. As such, we have used a supersonic expansion discharge source to produce protonated formaldehyde, and recorded its spectrum using millimeter-submillimeter direct absorption spectroscopy. The rotational spectrum was recorded from 350-1000 GHz. Here we will present the experimental design, specifically focusing on the optimization of the source for production of organic ions. We will also present the spectroscopic results for protonated formaldehyde and a spectral analysis with associated prediction that can be extended to frequencies above 1 THz.

  4. Submillimeter Spectroscopy of the R Coronae Australis Molecular Cloud Region

    Science.gov (United States)

    Dunn, Marina Madeline; Walker, Christopher K.; Pat, Terrance; Sirsi, Siddhartha; Swift, Brandon J.; Peters, William L.

    2018-01-01

    The Interstellar Medium is comprised of large amounts of gas and dust which coalesce to form stars. Observing in the Terahertz regime of the electromagnetic spectrum, approximately 0.3 -300 microns, allows astronomers to study the ISM in unprecedented detail. Using the high spectral resolution imaging system of the SuperCam receiver, a 64-pixel array previously installed on the Submillimeter Telescope on Mt. Graham, AZ, we have begun a 500 square degree survey of the galactic plane. This instrument was designed to do a complete survey of the Milky Way from the ground, with the main focus being to observe two specific transitions of the carbon monoxide molecule, 12CO(3-2) and 13CO(3-2), at 345 GHz. In this work, we present results from these observations for the R Coronae Australis (R Cr A) complex, a region in the southern hemisphere of the sky, using spectroscopic data from a portion of the survey to gain better insight into the life cycle of the ISM. The majority of stars being formed here are similar to the stellar class of the Sun, making it an excellent area of observing interest. Using these results, we attempt to better ascertain the large-scale structure and kinematics inside of the molecular cloud.

  5. Wavelength sweepable laser source

    DEFF Research Database (Denmark)

    2014-01-01

    Wavelength sweepable laser source is disclosed, wherein the laser source is a semiconductor laser source adapted for generating laser light at a lasing wavelength. The laser source comprises a substrate, a first reflector, and a second reflector. The first and second reflector together defines...... and having a rest position, the second reflector and suspension together defining a microelectromechanical MEMS oscillator. The MEMS oscillator has a resonance frequency and is adapted for oscillating the second reflector on either side of the rest position.; The laser source further comprises electrical...... connections adapted for applying an electric field to the MEMS oscillator. Furthermore, a laser source system and a method of use of the laser source are disclosed....

  6. DETECTION OF AN ULTRA-BRIGHT SUBMILLIMETER GALAXY BEHIND THE SMALL MAGELLANIC CLOUD

    Energy Technology Data Exchange (ETDEWEB)

    Takekoshi, Tatsuya; Minamidani, Tetsuhiro; Sorai, Kazuo; Habe, Asao [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Tamura, Yoichi; Kohno, Kotaro [Institute of Astronomy, University of Tokyo, Osawa, Mitaka, Tokyo 181-0015 (Japan); Oogi, Taira [Department of Physics, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Ezawa, Hajime; Komugi, Shinya; Mizuno, Norikazu; Muller, Erik; Kawamura, Akiko [Chile Observatory, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Oshima, Tai [Nobeyama Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Scott, Kimberly S. [North American ALMA Science Center, National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Austermann, Jason E. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Tosaki, Tomoka [Joetsu University of Education, Joetsu, Niigata 943-8512 (Japan); Onishi, Toshikazu [Department of Physical Science, Osaka Prefecture University, Gakuen 1-1, Sakai, 599-8531 Osaka (Japan); Fukui, Yasuo [Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Matsuo, Hiroshi [Advanced Technology Center, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Aretxaga, Itziar [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), 72000 Puebla (Mexico); and others

    2013-09-10

    We report the discovery of a new ultra-bright submillimeter galaxy (SMG) behind the Small Magellanic Cloud (SMC). This SMG is detected as a 43.3 {+-} 8.4 mJy point source (MM J01071-7302, hereafter MMJ0107) in the 1.1 mm continuum survey of the SMC by AzTEC on the ASTE telescope. MMJ0107 is also detected in the radio (843 MHz), Herschel/SPIRE, Spitzer MIPS 24 {mu}m, all IRAC bands, Wide-field Infrared Survey Explorer, and near-infrared (J, H, K{sub S} ). We find an optical (U, B, V) source, which might be the lensing object, at a distance of 1.''4 from near-infrared and IRAC sources. Photometric redshift estimates for the SMG using representative spectral energy distribution templates show the redshifts of 1.4-3.9. We estimate total far-infrared luminosity of (0.3-2.2) Multiplication-Sign 10{sup 14} {mu}{sup -1} L{sub Sun} and a star formation rate of 5600-39, 000 {mu}{sup -1} M{sub Sun} yr{sup -1}, where {mu} is the gravitational magnification factor. This apparent extreme star formation activity is likely explained by a highly magnified gravitational lens system.

  7. An alma survey of submillimeter galaxies in the extended Chandra deep field-south: The agn fraction and X-ray properties of submillimeter galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S. X.; Brandt, W. N.; Luo, B. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Smail, I.; Alexander, D. M.; Danielson, A. L. R.; Karim, A.; Simpson, J. M.; Swinbank, A. M. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Hodge, J. A.; Walter, F. [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Lehmer, B. D. [The Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States); Wardlow, J. L. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Xue, Y. Q. [Key Laboratory for Research in Galaxies and Cosmology, Center for Astrophysics, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Chapman, S. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Coppin, K. E. K. [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Dannerbauer, H. [Universität Wien, Institute für Astrophysik, Türkenschanzstraße 17, 1180 Wien (Austria); De Breuck, C. [European Southern Observatory, Karl-Schwarzschild Straße 2, D-85748 Garching (Germany); Menten, K. M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Van der Werf, P., E-mail: xxw131@psu.edu, E-mail: niel@astro.psu.edu [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands)

    2013-12-01

    The large gas and dust reservoirs of submillimeter galaxies (SMGs) could potentially provide ample fuel to trigger an active galactic nucleus (AGN), but previous studies of the AGN fraction in SMGs have been controversial largely due to the inhomogeneity and limited angular resolution of the available submillimeter surveys. Here we set improved constraints on the AGN fraction and X-ray properties of the SMGs with Atacama Large Millimeter/submillimeter Array (ALMA) and Chandra observations in the Extended Chandra Deep Field-South (E-CDF-S). This study is the first among similar works to have unambiguously identified the X-ray counterparts of SMGs; this is accomplished using the fully submillimeter-identified, statistically reliable SMG catalog with 99 SMGs from the ALMA LABOCA E-CDF-S Submillimeter Survey. We found 10 X-ray sources associated with SMGs (median redshift z = 2.3), of which eight were identified as AGNs using several techniques that enable cross-checking. The other two X-ray detected SMGs have levels of X-ray emission that can be plausibly explained by their star formation activity. Six of the eight SMG-AGNs are moderately/highly absorbed, with N {sub H} > 10{sup 23} cm{sup –2}. An analysis of the AGN fraction, taking into account the spatial variation of X-ray sensitivity, yields an AGN fraction of 17{sub −6}{sup +16}% for AGNs with rest-frame 0.5-8 keV absorption-corrected luminosity ≥7.8 × 10{sup 42} erg s{sup –1}; we provide estimated AGN fractions as a function of X-ray flux and luminosity. ALMA's high angular resolution also enables direct X-ray stacking at the precise positions of SMGs for the first time, and we found four potential SMG-AGNs in our stacking sample.

  8. Diamond Heat-Spreader for Submillimeter-Wave Frequency Multipliers

    Science.gov (United States)

    Lin, Robert H.; Schlecht, Erich T.; Chattopadhyay, Goutam; Gill, John J.; Mehdi, Imran; Siegel, Peter H.; Ward, John S.; Lee, Choonsup; Thomas, Bertrand C.; Maestrini, Alain

    2010-01-01

    The planar GaAs Shottky diode frequency multiplier is a critical technology for the local oscillator (LO) for submillimeter- wave heterodyne receivers due to low mass, tenability, long lifetime, and room-temperature operation. The use of a W-band (75-100 GHz) power amplifier followed by a frequency multiplier is the most common for submillimeter-wave sources. Its greatest challenge is to provide enough input power to the LO for instruments onboard future planetary missions. Recently, JPL produced 800 mW at 92.5 GHz by combining four MMICs in parallel in a balanced configuration. As more power at W-band is available to the multipliers, their power-handling capability be comes more important. High operating temperatures can lead to degradation of conversion efficiency or catastrophic failure. The goal of this innovation is to reduce the thermal resistance by attaching diamond film as a heat-spreader on the backside of multipliers to improve their power-handling capability. Polycrystalline diamond is deposited by hot-filament chemical vapor deposition (CVD). This diamond film acts as a heat-spreader to both the existing 250- and 300-GHz triplers, and has a high thermal conductivity (1,000-1,200 W/mK). It is approximately 2.5 times greater than copper (401 W/mK) and 20 times greater than GaAs (46 W/mK). It is an electrical insulator (resistivity approx. equals 10(exp 15) Ohms-cm), and has a low relative dielectric constant of 5.7. Diamond heat-spreaders reduce by at least 200 C at 250 mW of input power, compared to the tripler without diamond, according to thermal simulation. This superior thermal management provides a 100-percent increase in power-handling capability. For example, with this innovation, 40-mW output power has been achieved from a 250-GHz tripler at 350-mW input power, while the previous triplers, without diamond, suffered catastrophic failures. This breakthrough provides a stepping-stone for frequency multipliers-based LO up to 3 THz. The future work

  9. ESPRIT - Exploratory Submillimeter sPace Radio Interferometric Telescope

    NARCIS (Netherlands)

    Wild, W.; Venema, L.; Cernicharo, J.; Esprit Study Team, [Unknown

    2007-01-01

    The far-infrared (FIR) wavelength regime is of prime importance for astrophysics. The study of ionic, atomic and molecular lines, many of them present in the FIR, provides important and unique information on the star and planet formation process occurring in interstellar clouds,and the life cycle of

  10. Submillimeter Galaxies as Progenitors of Compact Quiescent Galaxies

    Science.gov (United States)

    Toft, S.; Smolcic, V.; Magnelli, B.; Karim, A.; Zirm, A.; Michalowski, M.; Capak, P.; Sheth, K.; Schawinski, K.; Krogager, J.-K.; hide

    2014-01-01

    Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low-redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3 < z < 6). Simulations show that gas-rich major mergers can give rise to such starbursts, which produce dense remnants. Submillimeter-selected galaxies (SMGs) are prime examples of intense, gas-rich starbursts.With a new, representative spectroscopic sample of compact, quiescent galaxies at z = 2 and a statistically well-understood sample of SMGs, we show that z = 3-6 SMGs are consistent with being the progenitors of z = 2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses, and internal velocities. Assuming an evolutionary connection, their space densities also match if the mean duty cycle of SMG starbursts is 42(sup+40) -29 Myr (consistent with independent estimates), which indicates that the bulk of stars in these massive galaxies were formed in a major, early surge of star formation. These results suggest a coherent picture of the formation history of the most massive galaxies in the universe, from their initial burst of violent star formation through their appearance as high stellar-density galaxy cores and to their ultimate fate as giant ellipticals.

  11. Evidence for Dust Clearing Through Resolved Submillimeter Imaging

    Science.gov (United States)

    Brown, J. M.; Blake, G. A.; Qi, C.; Dullemond, C. P.; Wilner, D. J.; Williams, J. P.

    2009-10-01

    Mid-infrared spectrophotometric observations have revealed a small subclass of circumstellar disks with spectral energy distributions (SEDs) suggestive of large inner gaps with low dust content. However, such data provide only an indirect and model-dependent method of finding central holes. Imaging of protoplanetry disks provides an independent check of SED modeling. We present here the direct characterization of three 33-47 AU radii inner gaps, in the disks around LkHα 330, SR 21N, and HD 135344B, via 340 GHz (880 μm) dust continuum aperture synthesis observations obtained with the Submillimeter Array (SMA). The large gaps are fully resolved at ~0farcs3 by the SMA data and mostly empty of dust, with less than (1-7.5) × 10-6 M sun of fine grained solids inside the holes. Gas (as traced by atomic accretion markers and CO 4.7 μm rovibrational emission) is still present in the inner regions of all three disks. For each, the inner hole exhibits a relatively steep rise in dust emission to the outer disk, a feature more likely to originate from the gravitational influence of a companion body than from a process expected to show a more shallow gradient like grain growth. Importantly, the good agreement between the spatially resolved data and spectrophotometry-based models lends confidence to current interpretations of SEDs, wherein the significant dust emission deficits arise from disks with inner gaps or holes. Further SED-based searches can therefore be expected to yield numerous additional candidates that can be examined at high spatial resolution.

  12. Submillimeter galaxies as progenitors of compact quiescent galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Toft, S.; Zirm, A.; Krogager, J.-K.; Man, A. W. S. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Mariesvej 30, DK-2100 Copenhagen (Denmark); Smolčić, V.; Krpan, J. [Physics Department, University of Zagreb, Bijenička cesta 32, 10002 Zagreb (Croatia); Magnelli, B.; Karim, A. [Argelander Institute for Astronomy, Auf dem Hügel 71, Bonn, D-53121 (Germany); Michalowski, M. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Capak, P. [Spitzer Science Center, 314-6 Caltech, 1201 East California Boulevard, Pasadena, CA 91125 (United States); Sheth, K. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Schawinski, K. [ETH Zurich, Institute for Astronomy, Department of Physics, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Wuyts, S.; Lutz, D.; Staguhn, J.; Berta, S. [MPE, Postfach 1312, D-85741 Garching (Germany); Sanders, D. [Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822 (United States); Mccracken, H. [Institut dAstrophysique de Paris, UMR7095 CNRS, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Riechers, D., E-mail: sune@dark-cosmology.dk [Department of Astronomy, Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)

    2014-02-20

    Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low-redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3 < z < 6). Simulations show that gas-rich major mergers can give rise to such starbursts, which produce dense remnants. Submillimeter-selected galaxies (SMGs) are prime examples of intense, gas-rich starbursts. With a new, representative spectroscopic sample of compact, quiescent galaxies at z = 2 and a statistically well-understood sample of SMGs, we show that z = 3-6 SMGs are consistent with being the progenitors of z = 2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses, and internal velocities. Assuming an evolutionary connection, their space densities also match if the mean duty cycle of SMG starbursts is 42{sub −29}{sup +40} Myr (consistent with independent estimates), which indicates that the bulk of stars in these massive galaxies were formed in a major, early surge of star formation. These results suggest a coherent picture of the formation history of the most massive galaxies in the universe, from their initial burst of violent star formation through their appearance as high stellar-density galaxy cores and to their ultimate fate as giant ellipticals.

  13. Wavelength conversion devices and techniques

    DEFF Research Database (Denmark)

    Stubkjær, Kristian; Jørgensen, Carsten; Danielsen, Søren Lykke

    1996-01-01

    wavelengths in an easy way and preferably without opto-electronic conversion. Here, we will first briefly look at advantages of employing optical wavelength converters in WDM networks and next review the optical wavelength conversion devices with emphasis on recent developments....

  14. EW WEIGHT DEPENDENT ROUTING AND WAVELENGTH ASSIGNMENT STRATEGY FOR ALL OPTICAL NETWORKS IN ABSENCE OF WAVELENGTH CONVERTERS

    Directory of Open Access Journals (Sweden)

    Shilpa S. Patil

    2015-09-01

    Full Text Available In wavelength division multiplexed all optical networks; lightpath establishes a connection between sending and receiving nodes bypassing the electronic processing at intermediate nodes. One of the prime objectives of Routing and Wavelength Assignment (RWA problem is to maximize the number of connections efficiently by choosing the best routes. Although there are several algorithms available, improving the blocking performance in optical networks and finding optimal solutions for RWA problem has still remained a challenging issue. Wavelength conversion can be helpful in restricting the problem of wavelength continuity constraint but it increases complexity in the network. In this paper, we propose new weight dependent routing and wavelength assignment strategy for all optical networks without use of wavelength converters. Proposed weight function reduces blocking probability significantly, improving the network performance at various load conditions. Further, due to absence of wavelength converters, the cost and complexity of network reduces. Results show that the proposed strategy performs better than earlier reported methods.

  15. Micro-Spec: An Ultra-Compact, High-Sensitivity Spectrometer for Far-Infrared and Sub-Millimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe; Hsieh, Wen-Ting; Huang, Wei-Chung; Moseley, S. Harvey; Stevenson, Thomas R.; Wollack, Edward J.

    2013-01-01

    High-performance, integrated spectrometers operating in the far-infrared and sub-millimeter promise to be powerful tools for the exploration of the epochs of reionization and initial galaxy formation. These devices, using high-efficiency superconducting transmission lines, can achieve the performance of a meter-scale grating spectrometer in an instrument implemented on a four-inch silicon wafer. Such a device, when combined with a cryogenic telescope in space, provides an enabling capability for studies of the early universe. Here, the optical design process for Micro-Spec (mu-Spec) is presented, with particular attention given to its two-dimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the stigmatization and minimization of the light path function in this bounded region, which results in an optimized geometrical configuration. A point design with an efficiency of approx. 90% has been developed for initial demonstration, and can serve as the basis for future instruments. Design variations on this implementation are also discussed, which can lead to lower efficiencies due to diffractive losses in the multimode region.

  16. Mu-Spec: A High Performance Compact Spectrometer for Submillimeter Astronomy

    Science.gov (United States)

    Hsieh, Wen-Ting; Moseley, Harvey; Stevenson, Thomas; Brown, Ari; Patel, Amil; U-yen, Kongpop; Ehsan, Negar; Cataldo, Giuseppe; Wollack, Ed

    2012-01-01

    We describe the Mu-Spec, an extremely compact high performance spectrometer for the submillimeter and millimeter spectral ranges. We have designed a fully integrated submillimeter spectrometer based on superconducting microstrip technology and fabricated its critical elements. Using low loss transmission lines, we can produce a fully integrated high resolution submillimeter spectrometer on a single four inch Si wafer. A resolution of 500 can readily be achieved with standard fabrication tolerance, higher with phase trimming. All functions of the spectrometer are integrated - light is coupled to the microstrip circuit with a planar antenna, the spectra discrimination is achieved using a synthetic grating, orders are separated using a built-in planar filter, and the light is detected using photon counting Microwave Kinetic Inductance Detectors (MKID). We will discus the design principle of the instrument, describe its technical advantages, and report the progress on the development of the instrument.

  17. Micro-Spec: A High Performance Compact Spectrometer for Submillimeter Astronomy

    Science.gov (United States)

    Hsieh, Wen-Ting; Moseley, Harvey; Stevenson, Thomas; Brown, Ari; Patel, Amil; U-Yen, Kongpop; Ehsan, Negar; Caltado, Giuseppe; Wollock, Edward

    2012-01-01

    We describe the micro-Spec, an extremely compact high performance spectrometer for the submillimeter and millimeter spectral ranges. We have designed a fully integrated submillimeter spectrometer based on superconducting microstrip technology and fabricated its critical elements. Using low loss transmission lines, we can produce a fully integrated high resolution submillimeter spectrometer on a single four inch Si wafer. A resolution of 500 can readily be achieved with standard fabrication tolerance, higher with phase trimming. All functions of the spectrometer are integrated - light is coupled to the micro strip circuit with a planar antenna, the spectra discrimination is achieved using a synthetic grating, orders are separated using a built-in planar filter, and the light is detected using photon counting Microwave Kinetic Inductance Detectors (MKID). We will discus the design principle of the instrument, describe its technical advantages, and report the progress on the development of the instrument.

  18. Ionoacoustic characterization of the proton Bragg peak with submillimeter accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Assmann, W., E-mail: walter.assmann@lmu.de; Reinhardt, S.; Lehrack, S.; Edlich, A.; Thirolf, P. G.; Parodi, K. [Department for Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748 (Germany); Kellnberger, S.; Omar, M.; Ntziachristos, V. [Institute for Biological and Medical Imaging, Technische Universität München and Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764 (Germany); Moser, M.; Dollinger, G. [Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr, Werner-Heisenberg-Weg 39, Neubiberg 85577 (Germany)

    2015-02-15

    Purpose: Range verification in ion beam therapy relies to date on nuclear imaging techniques which require complex and costly detector systems. A different approach is the detection of thermoacoustic signals that are generated due to localized energy loss of ion beams in tissue (ionoacoustics). Aim of this work was to study experimentally the achievable position resolution of ionoacoustics under idealized conditions using high frequency ultrasonic transducers and a specifically selected probing beam. Methods: A water phantom was irradiated by a pulsed 20 MeV proton beam with varying pulse intensity and length. The acoustic signal of single proton pulses was measured by different PZT-based ultrasound detectors (3.5 and 10 MHz central frequencies). The proton dose distribution in water was calculated by Geant4 and used as input for simulation of the generated acoustic wave by the matlab toolbox k-WAVE. Results: In measurements from this study, a clear signal of the Bragg peak was observed for an energy deposition as low as 10{sup 12} eV. The signal amplitude showed a linear increase with particle number per pulse and thus, dose. Bragg peak position measurements were reproducible within ±30 μm and agreed with Geant4 simulations to better than 100 μm. The ionoacoustic signal pattern allowed for a detailed analysis of the Bragg peak and could be well reproduced by k-WAVE simulations. Conclusions: The authors have studied the ionoacoustic signal of the Bragg peak in experiments using a 20 MeV proton beam with its correspondingly localized energy deposition, demonstrating submillimeter position resolution and providing a deep insight in the correlation between the acoustic signal and Bragg peak shape. These results, together with earlier experiments and new simulations (including the results in this study) at higher energies, suggest ionoacoustics as a technique for range verification in particle therapy at locations, where the tumor can be localized by ultrasound

  19. Internal rupture and rapid bouncing of impacting drops induced by submillimeter-scale textures

    Science.gov (United States)

    Zhang, Rui; Zhang, Xiwen; Hao, Pengfei; He, Feng

    2017-06-01

    We demonstrate an internal breakup mechanism for high Weber number drop impact on superhydrophobic surfaces uniformly patterned with submillimeter-scale textures, in which the liquid film ruptures from both interior and rim. The employment of submillimeter-scale posts could help decrease the critical Weber number of internal rupture, due to the small solid fraction and the large dimension ratio between primary structures and droplets. The internal rupture is found to promote more rapid drop bouncing than conventional rebound and rim breakup on superhydrophobic surfaces with small roughness, with a 10%-50% reduction of contact time. The internal rupture results from the film instability inside and the jet instability outside.

  20. Internal rupture and rapid bouncing of impacting drops induced by submillimeter-scale textures.

    Science.gov (United States)

    Zhang, Rui; Zhang, Xiwen; Hao, Pengfei; He, Feng

    2017-06-01

    We demonstrate an internal breakup mechanism for high Weber number drop impact on superhydrophobic surfaces uniformly patterned with submillimeter-scale textures, in which the liquid film ruptures from both interior and rim. The employment of submillimeter-scale posts could help decrease the critical Weber number of internal rupture, due to the small solid fraction and the large dimension ratio between primary structures and droplets. The internal rupture is found to promote more rapid drop bouncing than conventional rebound and rim breakup on superhydrophobic surfaces with small roughness, with a 10%-50% reduction of contact time. The internal rupture results from the film instability inside and the jet instability outside.

  1. The JCMT Transient Survey: Identifying Submillimeter Continuum Variability over Several Year Timescales Using Archival JCMT Gould Belt Survey Observations

    Science.gov (United States)

    Mairs, Steve; Johnstone, Doug; Kirk, Helen; Lane, James; Bell, Graham S.; Graves, Sarah; Herczeg, Gregory J.; Scicluna, Peter; Bower, Geoffrey C.; Chen, Huei-Ru Vivien; Hatchell, Jennifer; Aikawa, Yuri; Chen, Wen-Ping; Kang, Miju; Kang, Sung-Ju; Lee, Jeong-Eun; Morata, Oscar; Pon, Andy; Scholz, Aleks; Takahashi, Satoko; Yoo, Hyunju; The JCMT Transient Team

    2017-11-01

    Investigating variability at the earliest stages of low-mass star formation is fundamental in understanding how a protostar assembles mass. While many simulations of protostellar disks predict non-steady accretion onto protostars, deeper investigation requires robust observational constraints on the frequency and amplitude of variability events characterized across the observable SED. In this study, we develop methods to robustly analyze repeated observations of an area of the sky for submillimeter variability in order to determine constraints on the magnitude and frequency of deeply embedded protostars. We compare 850 μm JCMT Transient Survey data with archival JCMT Gould Belt Survey data to investigate variability over 2-4 year timescales. Out of 175 bright, independent emission sources identified in the overlapping fields, we find seven variable candidates, five of which we classify as Strong, and the remaining two we classify as Extended to indicate that the latter are associated with larger-scale structure. For the Strong variable candidates, we find an average fractional peak brightness change per year of | 4.0| % {{yr}}-1, with a standard deviation of 2.7 % {{yr}}-1. In total, 7% of the protostars associated with 850 μm emission in our sample show signs of variability. Four of the five Strong sources are associated with a known protostar. The remaining source is a good follow-up target for an object that is anticipated to contain an enshrouded, deeply embedded protostar. In addition, we estimate the 850 μm periodicity of the submillimeter variable source, EC 53, to be 567 ± 32 days, based on the archival Gould Belt Survey data.

  2. The rest-frame submillimeter spectrum of high-redshift, dusty, star-forming galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Spilker, J. S.; Marrone, D. P. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Aguirre, J. E. [University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Aravena, M. [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001 Vitacura Santiago (Chile); Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Béthermin, M. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CEA-Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Bradford, C. M. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Bothwell, M. S. [Cavendish Laboratory, University of Cambridge, JJ Thompson Ave, Cambridge CB3 0HA (United Kingdom); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Carlstrom, J. E.; Crawford, T. M. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Chapman, S. C. [Dalhousie University, Halifax, Nova Scotia (Canada); De Breuck, C.; Gullberg, B. [European Southern Observatory, Karl Schwarzschild Straße 2, D-85748 Garching (Germany); Fassnacht, C. D. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Gonzalez, A. H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Hezaveh, Y. [Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8 (Canada); Holzapfel, W. L., E-mail: jspilker@as.arizona.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); and others

    2014-04-20

    We present the average rest-frame spectrum of high-redshift dusty, star-forming galaxies from 250 to 770 GHz. This spectrum was constructed by stacking Atacama Large Millimeter/submillimeter Array (ALMA) 3 mm spectra of 22 such sources discovered by the South Pole Telescope and spanning z = 2.0-5.7. In addition to multiple bright spectral features of {sup 12}CO, [C I], and H{sub 2}O, we also detect several faint transitions of {sup 13}CO, HCN, HNC, HCO{sup +}, and CN, and use the observed line strengths to characterize the typical properties of the interstellar medium of these high-redshift starburst galaxies. We find that the {sup 13}CO brightness in these objects is comparable to that of the only other z > 2 star-forming galaxy in which {sup 13}CO has been observed. We show that the emission from the high-critical density molecules HCN, HNC, HCO{sup +}, and CN is consistent with a warm, dense medium with T {sub kin} ∼ 55 K and n{sub H{sub 2}}≳10{sup 5.5} cm{sup –3}. High molecular hydrogen densities are required to reproduce the observed line ratios, and we demonstrate that alternatives to purely collisional excitation are unlikely to be significant for the bulk of these systems. We quantify the average emission from several species with no individually detected transitions, and find emission from the hydride CH and the linear molecule CCH for the first time at high redshift, indicating that these molecules may be powerful probes of interstellar chemistry in high-redshift systems. These observations represent the first constraints on many molecular species with rest-frame transitions from 0.4 to 1.2 mm in star-forming systems at high redshift, and will be invaluable in making effective use of ALMA in full science operations.

  3. High-resolution submillimeter and near-infrared studies of the transition disk around Sz 91

    Energy Technology Data Exchange (ETDEWEB)

    Tsukagoshi, Takashi; Momose, Munetake [College of Science, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512 (Japan); Hashimoto, Jun [Department of Physics and Astronomy, The University of Oklahoma, 440 West Brooks Street, Norman, OK 73019 (United States); Kudo, Tomoyuki; Saito, Masao; Ohashi, Nagayoshi; Kawabe, Ryohei; Akiyama, Eiji [National Astronomical Observatory Japan (NAOJ), Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Andrews, Sean; Wilner, David [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kitamura, Yoshimi [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Yoshinodai 3-1-1, Sagamihara, Kanagawa 229-8510 (Japan); Abe, Lyu [Lboratoire Lagrange (UMR 7293), Université de Nice-Sophia Antipolis, CNRS, Observatoire de la Côte d' Azur, 28 avenue Valrose, F-06108 Nice Cedex 2 (France); Brandner, Wolfgang [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Brandt, Timothy D. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States); Carson, Joseph [Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States); Currie, Thayne [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street M5S 3H4, Toronto, Ontario (Canada); Egner, Sebastian E.; Guyon, Olivier [Subaru Telescope, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Goto, Miwa [Universitäts-Sternwarte München, Ludwig-Maximilians-Universität, Scheinerstr. 1, D-81679 München (Germany); Grady, Carol, E-mail: ttsuka@mx.ibaraki.ac.jp [Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others

    2014-03-10

    To reveal the structures of a transition disk around a young stellar object in Lupus, Sz 91 , we have performed aperture synthesis 345 GHz continuum and CO(3-2) observations with the Submillimeter Array (∼1''-3'' resolution) and high-resolution imaging of polarized intensity at the K{sub s} -band using the HiCIAO instrument on the Subaru Telescope (0.''25 resolution). Our observations successfully resolved the inner and outer radii of the dust disk to be 65 and 170 AU, respectively, which indicates that Sz 91 is a transition disk source with one of the largest known inner holes. The model fitting analysis of the spectral energy distribution reveals an H{sub 2} mass of 2.4 × 10{sup –3} M {sub ☉} in the cold (T < 30 K) outer part at 65 AU 3 × 10{sup –9} M {sub ☉}) of hot (T ∼ 180 K) dust possibly remains inside the inner hole of the disk. The structure of the hot component could be interpreted as either an unresolved self-luminous companion body (not directly detected in our observations) or a narrow ring inside the inner hole. Significant CO(3-2) emission with a velocity gradient along the major axis of the dust disk is concentrated on the Sz 91 position, suggesting a rotating gas disk with a radius of 420 AU. The Sz 91 disk is possibly a rare disk in an evolutionary stage immediately after the formation of protoplanets because of the large inner hole and the lower disk mass than other transition disks studied thus far.

  4. Measurement of plasma conductivity using faraday rotation of submillimeter waves

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmenko, P.J.; Self, S.A.

    1983-03-01

    This paper examines the application of Faraday rotation to the measurement of electron combustion MHD plasmas. Details on the design of a working system are given, including the selection of operating wavelength. A theoretical comparison between the Faraday rotation technique and two-path interferometry shows Faraday rotation in its simplest form to be somewhat less sensitive to changes in electron concentration. This deficit can be balanced against greater immunity to vibration and thermal drift. Improved techniques of measuring the rotation angle promise greater sensitivity. A preliminary experiment has verified the technique.

  5. Laser system with wavelength converter

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to an apparatus comprising a diode laser (10) providing radiation in a first wavelength interval, a radiation conversion unit (12) having an input and an output, the radiation converter configured to receive the radiation in the first wavelength interval from the diode...... laser at the input, the radiation conversion unit configured to convert the radiation in the first wavelength interval to radiation in a second wavelength interval and the output configured to output the converted radiation, the second wavelength interval having one end point outside the first...... wavelength interval. Further, the invention relates to a method of optically pumping a target laser (14) in a laser system, the laser system comprising a laser source providing radiation at a first frequency, the laser source being optically connected to an input of a frequency converter, the frequency...

  6. Topology optimised wavelength dependent splitters

    DEFF Research Database (Denmark)

    Hede, K. K.; Burgos Leon, J.; Frandsen, Lars Hagedorn

    A photonic crystal wavelength dependent splitter has been constructed by utilising topology optimisation1. The splitter has been fabricated in a silicon-on-insulator material (Fig. 1). The topology optimised wavelength dependent splitter demonstrates promising 3D FDTD simulation results. This com......A photonic crystal wavelength dependent splitter has been constructed by utilising topology optimisation1. The splitter has been fabricated in a silicon-on-insulator material (Fig. 1). The topology optimised wavelength dependent splitter demonstrates promising 3D FDTD simulation results...

  7. COMPACT STARBURSTS IN z similar to 3-6 SUBMILLIMETER GALAXIES REVEALED BY ALMA

    NARCIS (Netherlands)

    Ikarashi, Soh; Ivison, R. J.; Caputi, Karina I.; Aretxaga, Itziar; Dunlop, James S.; Hatsukade, Bunyo; Hughes, David H.; Iono, Daisuke; Izumi, Takuma; Kawabe, Ryohei; Kohno, Kotaro; Lagos, Claudia D. P.; Motohara, Kentaro; Nakanishi, Kouichiro; Ohta, Kouji; Tamura, Yoichi; Umehata, Hideki; Wilson, Grant W.; Yabe, Kiyoto; Yun, Min S.

    2015-01-01

    We report the source size distribution, as measured by ALMA millimetric continuum imaging, of a sample of 13 AzTEC-selected submillimeter galaxies (SMGs) at z(phot) similar to 3-6. Their infrared luminosities and star formation rates (SFRs) are L-IR similar to, 2-6 x 10(12) L-circle dot and similar

  8. VizieR Online Data Catalog: Sub-millimeter spectra of 2-hydroxyacetonitrile (Margules+, 2017)

    Science.gov (United States)

    Margules, L.; McGuire, B. A.; Senent, M. L.; Motiyenko, R. A.; Remijan, A.; Guillemin, J. C.

    2017-02-01

    Measured frequencies and residuals from the global fit of the submillimeter-wave data for 2-hydroxyacetonitrile and files used for SPFIT. Detailled explanations on SPFIT could be found at https://www.astro.uni-koeln.de/cdms/pickett (4 data files).

  9. ALMA Partners Break Ground on World's Largest Millimeter Wavelength Telescope

    Science.gov (United States)

    2003-11-01

    space through which light cannot penetrate." Wayne Van Citters, Division Director for the NSF's Division of Astronomical Sciences represented Dr. Colwell at this ceremony. "ALMA will be a giant leap forward for our studies of this relatively little explored spectral window towards the Universe," said Dr. Catherine Cesarsky, Director General of ESO. "With ESO leading the European part of this ambitious and forward-looking project, the impact of ALMA will be felt in wide circles on our continent. Together with our partners in North America and Chile, we are all looking forward to the truly outstanding opportunities that will be offered by ALMA, also to young scientists and engineers." SCIENCE WITH ALMA ALMA will receive millimeter and sub-millimeter wavelength electromagnetic radiation from space. This portion of the spectrum, which is more energetic than most radio waves yet less energetic than visible and infrared light, holds the key to understanding a great variety of fundamental processes, including planet and star formation, and the formation and evolution of galaxies and galaxy clusters in the early Universe. The possibility to detect emission from organic and other molecules in space is of particularly high interest. "ALMA will push the limits of engineering to provide a telescope array at a fantastic site for astronomers to peer at the beginnings of the Universe, galaxies, stars and planets, and perhaps even life," said Dr. Fred K.Y. Lo, director of the National Radio Astronomy Observatory (NRAO). The millimeter and sub-millimeter radiation that ALMA will study is able to penetrate the vast clouds of dust and gas that populate interstellar and intergalactic space, revealing previously hidden details about astronomical objects. This energy, however, is blocked by atmospheric moisture here on Earth. To conduct research in this critical portion of the spectrum, astronomers need a site that is very dry, and preferably at a very high altitude where the atmosphere is

  10. Solar Prominence Modelling and Plasma Diagnostics at ALMA Wavelengths

    Science.gov (United States)

    Rodger, Andrew; Labrosse, Nicolas

    2017-09-01

    Our aim is to test potential solar prominence plasma diagnostics as obtained with the new solar capability of the Atacama Large Millimeter/submillimeter Array (ALMA). We investigate the thermal and plasma diagnostic potential of ALMA for solar prominences through the computation of brightness temperatures at ALMA wavelengths. The brightness temperature, for a chosen line of sight, is calculated using the densities of electrons, hydrogen, and helium obtained from a radiative transfer code under non-local thermodynamic equilibrium (non-LTE) conditions, as well as the input internal parameters of the prominence model in consideration. Two distinct sets of prominence models were used: isothermal-isobaric fine-structure threads, and large-scale structures with radially increasing temperature distributions representing the prominence-to-corona transition region. We compute brightness temperatures over the range of wavelengths in which ALMA is capable of observing (0.32 - 9.6 mm), however, we particularly focus on the bands available to solar observers in ALMA cycles 4 and 5, namely 2.6 - 3.6 mm (Band 3) and 1.1 - 1.4 mm (Band 6). We show how the computed brightness temperatures and optical thicknesses in our models vary with the plasma parameters (temperature and pressure) and the wavelength of observation. We then study how ALMA observables such as the ratio of brightness temperatures at two frequencies can be used to estimate the optical thickness and the emission measure for isothermal and non-isothermal prominences. From this study we conclude that for both sets of models, ALMA presents a strong thermal diagnostic capability, provided that the interpretation of observations is supported by the use of non-LTE simulation results.

  11. Pixel super resolution using wavelength scanning

    Science.gov (United States)

    2016-04-08

    Lens-free spectral light- field fusion microscopy for contrast - and resolution-enhanced imaging of biological specimens. Opt Lett 2015; 40: 3862–3865...31 Kühn J, Colomb T, Montfort F, Charrière F, Emery Y et al. Real- time dual-wavelength digital holographic microscopy with a single hologram...on-chip microscopy . Nat Methods 2012; 9: 889–895. 49 Zernike F. Phase contrast , a new method for the microscopic observation of transparent objects

  12. Wavelength conversion techniques and devices

    DEFF Research Database (Denmark)

    Danielsen, Søren Lykke; Mikkelsen, Benny; Hansen, Peter Bukhave

    1997-01-01

    Taking into account the requirements to the converters e.g., bit rate transparency (at least up to 10 Gbit/s), polarisation independence, wavelength independence, moderate input power levels, high signal-to-noise ratio and high extinction ratio interferometric wavelength convertors are very...

  13. Interference comparator for laser diode wavelength and wavelength instability measurement

    Science.gov (United States)

    Dobosz, Marek; KoŻuchowski, Mariusz

    2016-04-01

    Method and construction of a setup, which allows measuring the wavelength and wavelength instability of the light emitted by a laser diode (or a laser light source with a limited time coherence in general), is presented. The system is based on Twyman-Green interferometer configuration. Proportions of phases of the tested and reference laser's interference fringe obtained for a set optical path difference are a measure of the unknown wavelength. Optical path difference in interferometer is stabilized. The interferometric comparison is performed in vacuum chamber. The techniques of accurate fringe phase measurements are proposed. The obtained relative standard uncertainty of wavelength evaluation in the tested setup is about 2.5 ṡ 10-8. Uncertainty of wavelength instability measurement is an order of magnitude better. Measurement range of the current setup is from 500 nm to 650 nm. The proposed technique allows high accuracy wavelength measurement of middle or low coherence sources of light. In case of the enlarged and complex frequency distribution of the laser, the evaluated wavelength can act as the length master in interferometer for displacement measurement.

  14. THE SCUBA-2 COSMOLOGY LEGACY SURVEY: ALMA RESOLVES THE REST-FRAME FAR-INFRARED EMISSION OF SUB-MILLIMETER GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J. M.; Smail, Ian; Swinbank, A. M.; Chen, Chian-Chou; Danielson, A. L. R.; Edge, A. C.; Ma, C.-J. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Almaini, O.; Conselice, C.; Hartley, W. G.; Lani, C. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Bremer, M. N.; Coppin, K. E. K. [School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 3J5 (Canada); Dunlop, J. S.; Ivison, R. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford HIll, Edinburgh EH9 3HJ (United Kingdom); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Geach, J. E. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Karim, A., E-mail: j.m.simpson@dur.ac.uk [Argelander-Institute for Astronomy, Bonn University, Auf dem Hügel 71, D-53121 Bonn (Germany); and others

    2015-01-20

    We present high-resolution (0.''3) Atacama Large Millimeter Array 870 μm imaging of 52 sub-millimeter galaxies (SMGs) in the Ultra Deep Survey field to investigate the size and morphology of the sub-millimeter (sub-mm) emission on 2-10 kpc scales. We derive a median intrinsic angular size of FWHM = 0.''30 ± 0.''04 for the 23 SMGs in the sample detected at a signal-to-noise ratio (S/N) >10. Using the photometric redshifts of the SMGs we show that this corresponds to a median physical half-light diameter of 2.4 ± 0.2 kpc. A stacking analysis of the SMGs detected at S/N <10 shows they have sizes consistent with the 870 μm bright SMGs in the sample. We compare our results to the sizes of SMGs derived from other multi-wavelength studies, and show that the rest-frame ∼250 μm sizes of SMGs are consistent with studies of resolved {sup 12}CO (J = 3-2 to 7-6) emission lines, but that sizes derived from 1.4 GHz imaging appear to be approximately two times larger on average, which we attribute to cosmic ray diffusion. The rest-frame optical sizes of SMGs are around four times larger than the sub-millimeter sizes, indicating that the star formation in these galaxies is compact relative to the pre-existing stellar distribution. The size of the starburst region in SMGs is consistent with the majority of the star formation occurring in a central region, a few kiloparsecs in extent, with a median star formation rate surface density of 90 ± 30 M {sub ☉} yr{sup –1} kpc{sup –2}, which may suggest that we are witnessing an intense period of bulge growth in these galaxies.

  15. Wavelength dimensioning for wavelength-routed WDM satellite network

    Directory of Open Access Journals (Sweden)

    Liu Zhe

    2016-06-01

    Full Text Available Internet and broadband applications driven by data traffic demand have become key drivers for satellite constellations. The key technology to satisfy the high capacity requirements between satellites is optical satellite networks by means of wavelength division multiplexing inter-satellite links (ISLs with wavelength routing (WDM-OSN. Due to the limited optical amplifier bandwidth onboard the satellite, it is important to minimize the wavelength requirements to provision requests. However, ISLs should be dynamically established and deleted for each satellite according to its visible satellites. Furthermore, different link assignments will result in different topologies, hence yielding different routings and wavelength assignments. Thus, a perfect match model-based link assignment scheme (LAS-PMM is proposed to design an appropriate topology such that shorter path could be routed and less wavelengths could be assigned for each ISL along the path. Finally, simulation results show that in comparison to the regular Manhattan street network (MSN topology, wavelength requirements and average end-to-end delay based on the topology generated by LAS-PMM could be reduced by 24.8% and 12.4%, respectively.

  16. The ALMA early science view of FUor/EXor objects - V. Continuum disc masses and sizes

    Science.gov (United States)

    Cieza, Lucas A.; Ruíz-Rodríguez, Dary; Perez, Sebastian; Casassus, Simon; Williams, Jonathan P.; Zurlo, Alice; Principe, David A.; Hales, Antonio; Prieto, Jose L.; Tobin, John J.; Zhu, Zhaohuan; Marino, Sebastian

    2018-03-01

    Low-mass stars build a significant fraction of their total mass during short outbursts of enhanced accretion known as FUor and EXor outbursts. FUor objects are characterized by a sudden brightening of ˜5 mag at visible wavelengths within 1 yr and remain bright for decades. EXor objects have lower amplitude outbursts on shorter time-scales. Here we discuss a 1.3 mm Atacama Large Millimeter/submillimeter Array (ALMA) mini-survey of eight outbursting sources (three FUors, four EXors, and the borderline object V1647 Ori) in the Orion Molecular Cloud. While previous papers in this series discuss the remarkable molecular outflows observed in the three FUor objects and V1647 Ori, here we focus on the continuum data and the differences and similarities between the FUor and EXor populations. We find that FUor discs are significantly more massive (˜80-600 MJup) than the EXor objects (˜0.5-40 MJup). We also report that the EXor sources lack the prominent outflows seen in the FUor population. Even though our sample is small, the large differences in disc masses and outflow activity suggest that the two types of objects represent different evolutionary stages. The FUor sources seem to be rather compact (Rc < 20-40 au) and to have a smaller characteristic radius for a given disc mass when compared to T Tauri stars. V1118 Ori, the only known close binary system in our sample, is shown to host a disc around each one of the stellar components. The disc around HBC 494 is asymmetric, hinting at a structure in the outer disc or the presence of a second disc.

  17. THE INFLUENCE OF SUPERNOVA REMNANTS ON THE INTERSTELLAR MEDIUM IN THE LARGE MAGELLANIC CLOUD SEEN AT 20-600 μm WAVELENGTHS

    Energy Technology Data Exchange (ETDEWEB)

    Lakićević, Maša; Van Loon, Jacco Th. [Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom); Meixner, Margaret; Gordon, Karl; Roman-Duval, Julia; Seale, Jonathan [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Bot, Caroline [Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l' université, F-67000 Strasbourg (France); Babler, Brian [Department of Astronomy, 475 north Charter St., University of Wisconsin, Madison, WI 53706 (United States); Bolatto, Alberto [Laboratory of Millimeter Astronomy, University of Maryland, College Park, MD 29742 (United States); Engelbracht, Chad; Misselt, Karl; Montiel, Edward [Steward Observatory, University of Arizona, 933 North Cherry Ave., Tucson, AZ 85721 (United States); Filipović, Miroslav [University of Western Sydney, Locked Bag 1797, Penrith South DC, NSW 1797 (Australia); Hony, Sacha; Okumura, K.; Panuzzo, Pasquale; Sauvage, Marc [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Indebetouw, Remy [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22903 (United States); Patat, Ferdinando [European Organization for Astronomical Research in the Southern Hemisphere (ESO), Karl-Schwarzschild-Straße 2, D-85748 Garching bei München (Germany); Sonneborn, George, E-mail: m.lakicevic@keele.ac.uk [NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); and others

    2015-01-20

    We present the analysis of supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) and their influence on the environment at far-infrared (FIR) and submillimeter wavelengths. We use new observations obtained with the Herschel Space Observatory and archival data obtained with the Spitzer Space Telescope, to make the first FIR atlas of these objects. The SNRs are not clearly discernible at FIR wavelengths; however, their influence becomes apparent in maps of dust mass and dust temperature, which we constructed by fitting a modified blackbody to the observed spectral energy distribution in each sightline. Most of the dust that is seen is pre-existing interstellar dust in which SNRs leave imprints. The temperature maps clearly reveal SNRs heating surrounding dust, while the mass maps indicate the removal of 3.7{sub −2.5}{sup +7.5} M {sub ☉} of dust per SNR. This agrees with the calculations by others that significant amounts of dust are sputtered by SNRs. Under the assumption that dust is sputtered and not merely pushed away, we estimate a dust destruction rate in the LMC of 0.037{sub −0.025}{sup +0.075} M {sub ☉} yr{sup –1} due to SNRs, yielding an average lifetime for interstellar dust of 2{sub −1.3}{sup +4.0}×10{sup 7} yr. We conclude that sputtering of dust by SNRs may be an important ingredient in models of galactic evolution, that supernovae may destroy more dust than they produce, and that they therefore may not be net producers of long lived dust in galaxies.

  18. Observing the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping

    Science.gov (United States)

    White, S. M.; Iwai, K.; Phillips, N. M.; Hills, R. E.; Hirota, A.; Yagoubov, P.; Siringo, G.; Shimojo, M.; Bastian, T. S.; Hales, A. S.; Sawada, T.; Asayama, S.; Sugimoto, M.; Marson, R. G.; Kawasaki, W.; Muller, E.; Nakazato, T.; Sugimoto, K.; Brajša, R.; Skokić, I.; Bárta, M.; Kim, S.; Remijan, A. J.; de Gregorio, I.; Corder, S. A.; Hudson, H. S.; Loukitcheva, M.; Chen, B.; De Pontieu, B.; Fleishmann, G. D.; Gary, D. E.; Kobelski, A.; Wedemeyer, S.; Yan, Y.

    2017-07-01

    The Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope has commenced science observations of the Sun starting in late 2016. Since the Sun is much larger than the field of view of individual ALMA dishes, the ALMA interferometer is unable to measure the background level of solar emission when observing the solar disk. The absolute temperature scale is a critical measurement for much of ALMA solar science, including the understanding of energy transfer through the solar atmosphere, the properties of prominences, and the study of shock heating in the chromosphere. In order to provide an absolute temperature scale, ALMA solar observing will take advantage of the remarkable fast-scanning capabilities of the ALMA 12 m dishes to make single-dish maps of the full Sun. This article reports on the results of an extensive commissioning effort to optimize the mapping procedure, and it describes the nature of the resulting data. Amplitude calibration is discussed in detail: a path that uses the two loads in the ALMA calibration system as well as sky measurements is described and applied to commissioning data. Inspection of a large number of single-dish datasets shows significant variation in the resulting temperatures, and based on the temperature distributions, we derive quiet-Sun values at disk center of 7300 K at λ = 3 mm and 5900 K at λ = 1.3 mm. These values have statistical uncertainties of about 100 K, but systematic uncertainties in the temperature scale that may be significantly larger. Example images are presented from two periods with very different levels of solar activity. At a resolution of about 25'', the 1.3 mm wavelength images show temperatures on the disk that vary over about a 2000 K range. Active regions and plages are among the hotter features, while a large sunspot umbra shows up as a depression, and filament channels are relatively cool. Prominences above the solar limb are a common feature of the single-dish images.

  19. Millimeter/Submillimeter Spectroscopy of TiO (X3Δr): The Rare Titanium Isotopologues

    Science.gov (United States)

    Lincowski, A. P.; Halfen, D. T.; Ziurys, L. M.

    2016-12-01

    Pure rotational spectra of the rare isotopologues of titanium oxide, 46TiO, 47TiO, 49TiO, and 50TiO, have been recorded using a combination of Fourier transform millimeter-wave (FTmmW) and millimeter/submillimeter direct absorption techniques in the frequency range 62-538 GHz. This study is the first complete spectroscopic characterization of these species in their X 3Δ r ground electronic states. The isotopologues were created by the reaction of N2O or O2 and titanium vapor, produced either by laser ablation or in a Broida-type oven, and observed in the natural Ti isotopic abundances. Between 10 and 11 rotational transitions J + 1 ≤ftrightarrow J were measured for each species, typically in all 3 spin-orbit ladders Ω = 1, 2, and 3. For 47TiO and 49TiO, hyperfine structure was resolved, originating from the titanium-47 and titanium-49 nuclear spins of I = 5/2 and 7/2, respectively. For the Ω = 1 and 3 components, the hyperfine structure was found to follow a classic Landé pattern, while that for Ω = 2 appeared to be perturbed, likely a result of mixing with the nearby isoconfigurational a 1Δ state. The spectra were analyzed with a case (a) Hamiltonian, and rotational, spin-orbit, and spin-spin parameters were determined for each species, as well as magnetic hyperfine and electric quadrupole constants for the two molecules with nuclear spins. The most abundant species, 48TiO, has been detected in circumstellar envelopes. These measurements will enable other titanium isotopologues to be studied at millimeter wavelengths, providing Ti isotope ratios that can test models of nucleosynthesis.

  20. Radio wavelength transients: Current and emerging prospects

    Science.gov (United States)

    Lazio, J.

    2008-03-01

    Known classes of radio wavelength transients range from the nearby stellar flares and radio pulsars to the distant Universe γ-ray burst afterglows. Hypothesized classes of radio transients include analogs of known objects, e.g., extrasolar planets emitting Jovian-like radio bursts and giant-pulse emitting pulsars in other galaxies, to the exotic, prompt emission from γ-ray bursts, evaporating black holes, and transmitters from other civilizations. A number of instruments and facilities are either under construction or in early observational stages and are slated to become available in the next few years. With a combination of wide fields of view and wavelength agility, the detection and study of radio transients will improve immensely.

  1. MIRA: Dual wavelength band instrument

    Directory of Open Access Journals (Sweden)

    Robert Georgii

    2015-08-01

    Full Text Available MIRA is a dual wavelength band instrument operated by Technische Universität München TUM, which provides neutrons over a wide range of wavelengths 3.5 Å < λ < 20 Å combining the two beam ports of MIRA-1 and MIRA-2. The instrument´s setup is modular and allows for various different cold neutron experiments such as diffraction, spectroscopy or reflectometry.

  2. Ground-Based Submillimeter Spectroscopic Cosmological Surveys and Synergies with Space FIR Surveys

    Science.gov (United States)

    Spinoglio, Luigi

    2018-01-01

    To study the dust obscured processes of both star formation and black hole accretion during galaxy evolution and establish their role, as well as their mutual feedback processes, rest frame IR to submillimeter spectroscopy is needed. At these frequencies dust extinction is at its minimum and a variety of atomic and molecular transitions, tracing most astrophysical domains, occur. A large ground based submillimeter telescope with a large field of view and high sensitivity in the TeraHertz domain will pave the way of future FIR space telescope missions, such as SPICA in the late 2020's and the Origins Telescope later. I will present predictions demonstrating the synergies of such instruments to fully understand galaxy evolution, during its obscured phase, which has built most of the stellar populations in galaxies.

  3. Mu-Spec - A High Performance Ultra-Compact Photon Counting spectrometer for Space Submillimeter Astronomy

    Science.gov (United States)

    Moseley, H.; Hsieh, W.-T.; Stevenson, T.; Wollack, E.; Brown, A.; Benford, D.; Sadleir; U-Yen, I.; Ehsan, N.; Zmuidzinas, J.; hide

    2011-01-01

    We have designed and are testing elements of a fully integrated submillimeter spectrometer based on superconducting microstrip technology. The instrument can offer resolving power R approximately 1500, and its high frequency cutoff is set by the gap of available high performance superconductors. All functions of the spectrometer are integrated - light is coupled to the microstrip circuit with a planar antenna, the spectra discrimination is achieved using a synthetic grating, orders are separated using planar filter, and detected using photon counting MKID detector. This spectrometer promises to revolutionize submillimeter spectroscopy from space. It replaces instruments with the scale of 1m with a spectrometer on a 10 cm Si wafer. The reduction in mass and volume promises a much higher performance system within available resource in a space mission. We will describe the system and the performance of the components that have been fabricated and tested.

  4. The Status of MUSIC: A Multicolor Sub/millimeter MKID Instrument

    Science.gov (United States)

    Schlaerth, J. A.; Czakon, N. G.; Day, P. K.; Downes, T. P.; Duan, R.; Glenn, J.; Golwala, S. R.; Hollister, M. I.; LeDuc, H. G.; Maloney, P. R.; Mazin, B. A.; Nguyen, H. T.; Noroozian, O.; Sayers, J.; Siegel, S.; Zmuidzinas, J.

    2012-05-01

    We report on the recent progress of the Multicolor Submillimeter (kinetic) Inductance Camera, or MUSIC. MUSIC will use antenna-coupled Microwave Kinetic Inductance Detectors to observe in four colors (150 GHz, 230 GHz, 290 GHz and 350 GHz) with 2304 detectors, 576 per band, at the Caltech Submillimeter Observatory. It will deploy in 2012. Here we provide an overview of the instrument, focusing on the array design. We have also used a pathfinder demonstration instrument, DemoCam, to identify problems in advance of the deployment of MUSIC. In particular, we identified two major limiters of our sensitivity: out-of-band light directly coupling to the detectors (i.e. not through the antenna), effectively an excess load, and a large 1/f contribution from our amplifiers and electronics. We discuss the steps taken to mitigate these effects to reach background-limited performance (BLIP) in observation.

  5. The Hawaii SCUBA-2 Lensing Cluster Survey: Are Low-luminosity Submillimeter Galaxies Detected in the Rest-frame UV?

    Science.gov (United States)

    Hsu, Li-Yen; Cowie, Lennox L.; Barger, Amy J.; Wang, Wei-Hao

    2017-12-01

    In this third paper of the Hawaii SCUBA-2 Lensing Cluster Survey series, we present Submillimeter Array (SMA) detections of six intrinsically faint 850 μm sources detected in SCUBA-2 images of the lensing cluster fields, A1689, A2390, A370, MACS J0717.5+3745, and MACS J1423.8+2404. Two of the SCUBA-2 sources split into doublets, yielding a total of eight SMA detections. The intrinsic 870 μm flux densities of these submillimeter galaxies (SMGs) are ∼1 mJy. Five of the eight SMGs are not detected in optical or near-infrared (NIR) images. The NIR-to-submillimeter flux ratios of these faint SMGs suggest that most of them are extremely dusty and/or are at very high redshifts. By combining these SMGs and several other samples from the literature, we find a bimodal distribution for the faint sources in the space of submillimeter flux versus NIR-to-submillimeter flux ratio. While most of the SMA-detected lensed sources are very obscured, the other SMGs with similar flux densities are mostly bright in the NIR. Future Atacama Large Millimeter/submillimeter Array observations of a large sample of SCUBA-2 sources in cluster fields will allow us to decide whether or not the bimodality we observe here really exists.

  6. Human brain diffusion tensor imaging at submillimeter isotropic resolution on a 3Tesla clinical MRI scanner.

    Science.gov (United States)

    Chang, Hing-Chiu; Sundman, Mark; Petit, Laurent; Guhaniyogi, Shayan; Chu, Mei-Lan; Petty, Christopher; Song, Allen W; Chen, Nan-kuei

    2015-09-01

    The advantages of high-resolution diffusion tensor imaging (DTI) have been demonstrated in a recent post-mortem human brain study (Miller et al., NeuroImage 2011;57(1):167-181), showing that white matter fiber tracts can be much more accurately detected in data at a submillimeter isotropic resolution. To our knowledge, in vivo human brain DTI at a submillimeter isotropic resolution has not been routinely achieved yet because of the difficulty in simultaneously achieving high resolution and high signal-to-noise ratio (SNR) in DTI scans. Here we report a 3D multi-slab interleaved EPI acquisition integrated with multiplexed sensitivity encoded (MUSE) reconstruction, to achieve high-quality, high-SNR and submillimeter isotropic resolution (0.85×0.85×0.85mm(3)) in vivo human brain DTI on a 3Tesla clinical MRI scanner. In agreement with the previously reported post-mortem human brain DTI study, our in vivo data show that the structural connectivity networks of human brains can be mapped more accurately and completely with high-resolution DTI as compared with conventional DTI (e.g., 2×2×2mm(3)). Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Wavelength-Modulated Diffraction System

    CERN Document Server

    Koganezawa, T; Nakamura, N; Yoshimura, Y; Iwasaki, H; Yamada, T; Shoji, T

    2001-01-01

    A new X-ray diffraction system has been constructed at the SR Center at Ritsumeikan University, in which the wavelength of the incident synchrotron radiation is continually and repeatedly changed over a definite range by rocking a couple of monochromator crystals while rotating a sample crystal and recording the diffraction pattern on a moving imaging plate detector. Bragg reflections appear as elongated spots and, if the wavelength range is chosen in the immediate vicinity of the absorption edge of an atom in the crystal, direct information on the phase of Bragg reflections can be derived from the intensity gradient of the elongated spots with respect to the wavelength. This method of phase determination is simple and free from the problem of intensity scaling encountered in the multi-wavelength diffraction method. When both a sample crystal and the detector are kept stationary while changing the wavelength, a pattern is obtained which is similar to Laue pattern, but there is a definite difference. The wavel...

  8. The Wavelength Conversion in WDM Networks

    Directory of Open Access Journals (Sweden)

    Miroslav Bahleda

    2004-01-01

    Full Text Available In this article we deal with a problem of wavelength conversion in WDM networks and with the wavelength conversion impact on throughput of network. The throughput of networks is determined in terms of blocking probability. The optical networks can be built without wavelength conversion or with full or limited wavelength conversion. Different traffic models are designed for different types of wavelength conversions, which describe performance of wavelength conversion. I describe some results of these models.

  9. Object and Objective Lost?

    DEFF Research Database (Denmark)

    Lopdrup-Hjorth, Thomas

    2015-01-01

    This paper explores the erosion and problematization of ‘the organization’ as a demarcated entity. Utilizing Foucault's reflections on ‘state-phobia’ as a source of inspiration, I show how an organization-phobia has gained a hold within Organization Theory (OT). By attending to the history...... of this organization-phobia, the paper argues that OT has become increasingly incapable of speaking about its core object. I show how organizations went from being conceptualized as entities of major importance to becoming theoretically deconstructed and associated with all kinds of ills. Through this history......, organizations as distinct entities have been rendered so problematic that they have gradually come to be removed from the center of OT. The costs of this have been rather significant. Besides undermining the grounds that gave OT intellectual credibility and legitimacy to begin with, the organization-phobia...

  10. Wavelength standards in the infrared

    CERN Document Server

    Rao, KN

    2012-01-01

    Wavelength Standards in the Infrared is a compilation of wavelength standards suitable for use with high-resolution infrared spectrographs, including both emission and absorption standards. The book presents atomic line emission standards of argon, krypton, neon, and xenon. These atomic line emission standards are from the deliberations of Commission 14 of the International Astronomical Union, which is the recognized authority for such standards. The text also explains the techniques employed in determining spectral positions in the infrared. One of the techniques used includes the grating con

  11. Wavelength shifting of intra-cavity photons: Adiabatic wavelength tuning in rapidly wavelength-swept lasers.

    Science.gov (United States)

    Jirauschek, Christian; Huber, Robert

    2015-07-01

    We analyze the physics behind the newest generation of rapidly wavelength tunable sources for optical coherence tomography (OCT), retaining a single longitudinal cavity mode during operation without repeated build up of lasing. In this context, we theoretically investigate the currently existing concepts of rapidly wavelength-swept lasers based on tuning of the cavity length or refractive index, leading to an altered optical path length inside the resonator. Specifically, we consider vertical-cavity surface-emitting lasers (VCSELs) with microelectromechanical system (MEMS) mirrors as well as Fourier domain mode-locked (FDML) and Vernier-tuned distributed Bragg reflector (VT-DBR) lasers. Based on heuristic arguments and exact analytical solutions of Maxwell's equations for a fundamental laser resonator model, we show that adiabatic wavelength tuning is achieved, i.e., hopping between cavity modes associated with a repeated build up of lasing is avoided, and the photon number is conserved. As a consequence, no fundamental limit exists for the wavelength tuning speed, in principle enabling wide-range wavelength sweeps at arbitrary tuning speeds with narrow instantaneous linewidth.

  12. Simulation study for the Stratospheric Inferred Wind (SIW) sub-millimeter limb sounder

    Science.gov (United States)

    Baron, Philippe; Murtagh, Donal; Eriksson, Patrick; Ochiai, Satoshi

    2017-04-01

    The Stratospheric Inferred Wind is a micro satellite mission studied within the Swedish Innosat program. The objective of the Innosat program is to launch a scientific satellite every two years [1]. SIW has been selected together with two other missions as a candidate for the 2nd launch planned in 2020. If realized, SIW will be the first sub-millimetre (SMM) satellite mission designed for measuring horizontal wind between 30-80 km. It has been shown that such systems can provide relevant wind information in this altitude range where other satellite techniques lack sensitivity [2,3]. The other objective of the mission will be to continue the stratospheric monitoring at a time in which the current observing systems will probably be ended. SIW is equipped with a small payload (40x40x44 cm3, 17 kg and power of 47 W) consisting of a radiometer cooled to 70 K, an auto-correlator spectrometer (8 GHz bandwidth, 1 MHz resolution), and an antenna of 30 cm. The atmospheric limb will be scanned from 10 to 80 km at two perpendicular directions in order to reconstruct the horizontal wind vectors from the measured line-of-sight winds. Those are obtained from the small Doppler shift of molecular lines contained in two spectral bands simultaneously measured with the double-side band radiometer. One of the bands is centred at 655 GHz to measure a cluster of strong O3 lines. It is the best spectral band for wind measurements [4]. The second band is centred near 625 GHz, and together with the first band, it will allow us to measure a large number of molecules relevant for studying the stratospheric dynamics and chemistry (N2O, H2O, ClO, HCl, BrO, NO, HNO3,...). The 655 GHz O3 lines also provide temperature between 10-80 km with similar performances as those obtained if an oxygen line would have been used instead. In this presentation we will introduce SIW and discuss the measurement performances derived from simulations studies. [1] http://www.ohb.de/press-releases-details/ohb-sweden

  13. Sensitivity Study of Ice Crystal Optical Properties in the 874 GHz Submillimeter Band

    Science.gov (United States)

    Tang, Guanglin; Yang, Ping; Wu, Dong L.

    2015-01-01

    Testing of an 874 GHz submillimeter radiometer on meteorological satellites is being planned to improve ice water content retrievals. In this paper we study the optical properties of ice cloud particles in the 874 GHz band. The results show that the bulk scattering and absorption coefficients of an ensemble of ice cloud particles are sensitive to the particle shape and effective diameter, whereas the latter is also sensitive to temperature. The co-polar back scattering cross-section is not sensitive to particle shape, temperature, and the effective diameter in the range of 50200 m.

  14. cluster-in-a-box: Statistical model of sub-millimeter emission from embedded protostellar clusters

    Science.gov (United States)

    Kristensen, Lars E.; Bergin, Edwin A.

    2016-10-01

    Cluster-in-a-box provides a statistical model of sub-millimeter emission from embedded protostellar clusters and consists of three modules grouped in two scripts. The first (cluster_distribution) generates the cluster based on the number of stars, input initial mass function, spatial distribution and age distribution. The second (cluster_emission) takes an input file of observations, determines the mass-intensity correlation and generates outflow emission for all low-mass Class 0 and I sources. The output is stored as a FITS image where the flux density is determined by the desired resolution, pixel scale and cluster distance.

  15. A deeply embedded young protoplanetary disk around L1489 IRS observed by the Submillimeter Array

    DEFF Research Database (Denmark)

    Brinch, C.; Crapsi, A.; Jørgensen, J. K.

    2007-01-01

    aim to identify whether an embedded Keplerian protoplanetary disk resides in the L1489 IRS system. Given the amount of envelope material still present, such a disk would respresent a very young example of a protoplanetary disk. Methods. Using the Submillimeter Array we have observed the HCO + J = 3......-2 line with a resolution of about 1". At this resolution a protoplanetary disk with a radius of a few hundred AUs should be detectable, if present. Radiative transfer tools are used to model the emission from both continuum and line data. Results. We find that these data are consistent with theoretical...

  16. Studying Star and Planet Formation with the Submillimeter Probe of the Evolution of Cosmic Structure

    Science.gov (United States)

    Rinehart, Stephen A.

    2005-01-01

    The Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) is a far- infrared/submillimeter (40-640 micrometers) spaceborne interferometry concept, studied through the NASA Vision Missions program. SPECS is envisioned as a 1-km baseline Michelson interferometer with two 4- meter collecting mirrors. To maximize science return, SPECS will have three operational modes: a photometric imaging mode, an intermediate spectral resolution mode (R approximately equal to 1000-3000), and a high spectral resolution mode (R approximately equal to 3 x 10(exp 5)). The first two of these modes will provide information on all sources within a 1 arcminute field-of-view (FOV), while the the third will include sources in a small (approximately equal to 5 arcsec) FOV. With this design, SPECS will have angular resolution comparable to the Hubble Space Telescope (50 mas) and sensitivity more than two orders of magnitude better than Spitzer (5sigma in 10ks of approximately equal to 3 x 10(exp 7) Jy Hz). We present here some of the results of the recently-completed Vision Mission Study for SPECS, and discuss the application of this mission to future studies of star and planet formation.

  17. Taiwanese antennas for the Sub-Millimeter Array: a progress report

    Science.gov (United States)

    Raffin, Phillippe A.; Liu, Ching-Tang; Cervera, Mathieu; Chang, Chi-Ling; Chen, Ming-Tang; Lee, Cheng-Ching; Lee, Typhoon; Lo, Kwok-Yung; Ma, Rwei-Ping; Martin, Robert N.; Martin-Cocher, Pierre; Ong, Ching-Long; Park, Yong-Sun; Tsai, Rong-Den; Wu, Enboa; Yang, Shun-Cheng; Yang, Tien-Szu

    2000-07-01

    The Academia Sinica, Institute for Astronomy and Astrophysics (ASIAA) is building two antennas to be added to the six antennas of the Sub-Millimeter Array (SMA) of the Smithsonian Astrophysical Observatory (SAO). The antennas have been designed at SAO and are currently under construction at Mauna Kea. ASIAA's two antennas are made in Taiwan from parts manufactured locally and imported from Europe and from the USA. This report will focus on the manufacturing and testing of 2 major components: the alidade and the reflector. We will emphasize the work done on the composite parts used in the 6- meter reflectors, namely the carbon fiber tubes for the backup structure, the carbon fiber legs of the quadrupod and the composite central hub. We will discuss the modal testing and pointing tests of the antennas. Finally this report will show how the Taiwanese industry was able to respond to the high manufacturing standards required to build sub-millimeter antennas. The design and manufacturing capabilities of the Aeronautical Research Laboratories and China Shipbuilding Corporation have made possible the construction of the telescopes in Taiwan.

  18. A Submillimeter Resolution PET Prototype Evaluated With an 18F Inkjet Printed Phantom

    Science.gov (United States)

    Schneider, Florian R.; Hohberg, Melanie; Mann, Alexander B.; Paul, Stephan; Ziegler, Sibylle I.

    2015-10-01

    This work presents a submillimeter resolution PET (Positron Emission Tomography) scanner prototype based on SiPM/MPPC arrays (Silicon Photomultiplier/Multi Pixel Photon Counter). Onto each active area a 1 ×1 ×20 mm3 LYSO (Lutetium-Yttrium-Oxyorthosilicate) scintillator crystal is coupled one-to-one. Two detector modules facing each other in a distance of 10.0 cm have been set up with in total 64 channels that are digitized by SADCs (Sampling Analog to Digital Converters) with 80 MHz, 10 bit resolution and FPGA (Field Programmable Gate Array) based extraction of energy and time information. Since standard phantoms are not sufficient for testing submillimeter resolution at which positron range is an issue, a 18F inkjet printed phantom has been used to explore the limit in spatial resolution. The phantom could be successfully reconstructed with an iterative MLEM (Maximum Likelihood Expectation Maximization) and an analytically calculated system matrix based on the DRF (Detector Response Function) model. The system yields a coincidence time resolution of 4.8 ns FWHM, an energy resolution of 20%-30% FWHM and a spatial resolution of 0.8 mm.

  19. Extending the LHC reach for new physics with sub-millimeter displaced vertices

    Science.gov (United States)

    Ito, Hayato; Jinnouchi, Osamu; Moroi, Takeo; Nagata, Natsumi; Otono, Hidetoshi

    2017-08-01

    Particles with a sub-millimeter decay length appear in many models of physics beyond the Standard Model. However, their longevity has been often ignored in their LHC searches and they have been regarded as promptly-decaying particles. In this letter, we show that, by requiring displaced vertices on top of the event selection criteria used in the ordinary search strategies for promptly-decaying particles, we can considerably extend the LHC reach for particles with a decay length of ≳ 100 μm. We discuss a way of reconstructing sub-millimeter displaced vertices by exploiting the same technique used for the primary vertex reconstruction on the assumption that the metastable particles are always pair-produced and their decay products contain high-pT jets. We show that, by applying a cut based on displaced vertices on top of standard kinematical cuts for the search of new particles, the LHC reach can be significantly extended if the decay length is ≳ 100 μm. In addition, we may measure the lifetime of the target particle through the reconstruction of displaced vertices, which plays an important role in understanding the new physics behind the metastable particles.

  20. The status of MUSIC: the multiwavelength sub-millimeter inductance camera

    Science.gov (United States)

    Sayers, Jack; Bockstiegel, Clint; Brugger, Spencer; Czakon, Nicole G.; Day, Peter K.; Downes, Thomas P.; Duan, Ran P.; Gao, Jiansong; Gill, Amandeep K.; Glenn, Jason; Golwala, Sunil R.; Hollister, Matthew I.; Lam, Albert; LeDuc, Henry G.; Maloney, Philip R.; Mazin, Benjamin A.; McHugh, Sean G.; Miller, David A.; Mroczkowski, Anthony K.; Noroozian, Omid; Nguyen, Hien Trong; Schlaerth, James A.; Siegel, Seth R.; Vayonakis, Anastasios; Wilson, Philip R.; Zmuidzinas, Jonas

    2014-08-01

    The Multiwavelength Sub/millimeter Inductance Camera (MUSIC) is a four-band photometric imaging camera operating from the Caltech Submillimeter Observatory (CSO). MUSIC is designed to utilize 2304 microwave kinetic inductance detectors (MKIDs), with 576 MKIDs for each observing band centered on 150, 230, 290, and 350 GHz. MUSIC's field of view (FOV) is 14' square, and the point-spread functions (PSFs) in the four observing bands have 45'', 31'', 25'', and 22'' full-widths at half maximum (FWHM). The camera was installed in April 2012 with 25% of its nominal detector count in each band, and has subsequently completed three short sets of engineering observations and one longer duration set of early science observations. Recent results from on-sky characterization of the instrument during these observing runs are presented, including achieved map- based sensitivities from deep integrations, along with results from lab-based measurements made during the same period. In addition, recent upgrades to MUSIC, which are expected to significantly improve the sensitivity of the camera, are described.

  1. Stratospheric isotopic water profiles from a single submillimeter limb scan by TELIS

    Directory of Open Access Journals (Sweden)

    A. de Lange

    2009-08-01

    Full Text Available Around 490 GHz relatively strong HDO and H218O emission lines can be found in the submillimeter thermal-emission spectrum of the Earth's atmosphere, along with lines of the principal isotopologue of water vapour. These can be used for remote sensing of the rare/principal isotope ratio in the stratosphere. A sensitivity study has been performed for retrieval simulations of water isotopologues from balloon-borne measurements by the limb sounder TELIS (TErahertz and submillimeter LImb Sounder. The study demonstrates the capability of TELIS to determine, from a single limb scan, the profiles for H218O and HDO between 20 km and 37 km with a retrieval error of ≈3 and a spatial resolution of 1.5 km, as determined by the width of the averaging kernel. In addition HDO can be retrieved in the range of 10–20 km, albeit with a strongly deteriorated retrieval error. Expected uncertainties in instrumental parameters have only limited impact on the retrieval results.

  2. A DETAILED GRAVITATIONAL LENS MODEL BASED ON SUBMILLIMETER ARRAY AND KECK ADAPTIVE OPTICS IMAGING OF A HERSCHEL-ATLAS SUBMILLIMETER GALAXY AT z = 4.243 {sup ,} {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Bussmann, R. S.; Gurwell, M. A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fu Hai; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Smith, D. J. B.; Bonfield, D.; Dunne, L. [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield, Herts AL10 9AB (United Kingdom); Dye, S.; Eales, S. [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Auld, R. [Cardiff University, School of Physics and Astronomy, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Baes, M.; Fritz, J. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Baker, A. J. [Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States); Cava, A. [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Clements, D. L.; Dariush, A. [Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Coppin, K. [Department of Physics, McGill University, Ernest Rutherford Building, 3600 Rue University, Montreal, Quebec, H3A 2T8 (Canada); Dannerbauer, H. [Universitaet Wien, Institut fuer Astronomie, Tuerkenschanzstrasse 17, 1180 Wien, Oesterreich (Austria); De Zotti, G. [Universita di Padova, Dipto di Astronomia, Vicolo dell' Osservatorio 2, IT 35122, Padova (Italy); Hopwood, R., E-mail: rbussmann@cfa.harvard.edu [Department of Physics and Astronomy, Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); and others

    2012-09-10

    We present high-spatial resolution imaging obtained with the Submillimeter Array (SMA) at 880 {mu}m and the Keck adaptive optics (AO) system at the K{sub S}-band of a gravitationally lensed submillimeter galaxy (SMG) at z = 4.243 discovered in the Herschel Astrophysical Terahertz Large Area Survey. The SMA data (angular resolution Almost-Equal-To 0.''6) resolve the dust emission into multiple lensed images, while the Keck AO K{sub S}-band data (angular resolution Almost-Equal-To 0.''1) resolve the lens into a pair of galaxies separated by 0.''3. We present an optical spectrum of the foreground lens obtained with the Gemini-South telescope that provides a lens redshift of z{sub lens} = 0.595 {+-} 0.005. We develop and apply a new lens modeling technique in the visibility plane that shows that the SMG is magnified by a factor of {mu} = 4.1 {+-} 0.2 and has an intrinsic infrared (IR) luminosity of L{sub IR} = (2.1 {+-} 0.2) Multiplication-Sign 10{sup 13} L{sub Sun }. We measure a half-light radius of the background source of r{sub s} = 4.4 {+-} 0.5 kpc which implies an IR luminosity surface density of {Sigma}{sub IR} (3.4 {+-} 0.9) Multiplication-Sign 10{sup 11} L{sub Sun} kpc{sup -2}, a value that is typical of z > 2 SMGs but significantly lower than IR luminous galaxies at z {approx} 0. The two lens galaxies are compact (r{sub lens} Almost-Equal-To 0.9 kpc) early-types with Einstein radii of {theta}{sub E1} 0.57 {+-} 0.01 and {theta}{sub E2} = 0.40 {+-} 0.01 that imply masses of M{sub lens1} = (7.4 {+-} 0.5) Multiplication-Sign 10{sup 10} M{sub Sun} and M{sub lens2} = (3.7 {+-} 0.3) Multiplication-Sign 10{sup 10} M{sub Sun }. The two lensing galaxies are likely about to undergo a dissipationless merger, and the mass and size of the resultant system should be similar to other early-type galaxies at z {approx} 0.6. This work highlights the importance of high spatial resolution imaging in developing models of strongly lensed galaxies

  3. Biosonar resolving power: Echo-acoustic perception of surface structures in the submillimeter range

    Directory of Open Access Journals (Sweden)

    Ralph eSimon

    2014-02-01

    Full Text Available The minimum distance for which two points still can be separated from each other defines the resolving power of a visual system. In an echo-acoustic context, the resolving power is usually measured as the smallest perceivable distance of two reflecting surfaces on the range axis and is found to be around half a millimetre for bats employing frequency modulated echolocation calls. Only few studies measured such thresholds with physical objects, most often bats were trained on virtual echoes i.e. echoes generated and played back by a computer; moreover, bats were sitting while they received the stimuli. In these studies differences in structure depth between 200 µm and 340 µm were found. However, these low thresholds were never verified for free-flying bats and real physical objects. Here, we show behavioural evidence that the echo-acoustic resolving power for surface structures in fact can be as low as measured for computer generated echoes and even lower, sometimes below 100 µm. We found this exceptional fine discrimination ability only when one of the targets showed spectral interferences in the frequency range of the bats' echolocation call while the other target did not. This result indicates that surface structure is likely to be perceived as a spectral quality rather than being perceived strictly in the time domain. Further, it points out that sonar resolving power directly depends on the highest frequency/shortest wavelength of the signal employed.

  4. High-speed multi-wavelength Fresnel diffraction imaging

    NARCIS (Netherlands)

    Noom, D.W.E.; Boonzajer Flaes, D.E.; Labordus, E.; Eikema, K.S.E.; Witte, S.M.

    2014-01-01

    We demonstrate a compact lensless microscope which can capture video-rate phase contrast images of moving objects and allows numerical scanning of the focal distance after recording. Using only an RGB-detector and illumination from a single mode fiber, diffraction patterns at three wavelengths are

  5. Comparing submillimeter polarized emission with near-infrared polarization of background stars for the Vela C molecular cloud

    Science.gov (United States)

    Santos, Fabio P.; Ade, Peter; Angilè, Francesco E.; Ashton, Peter; Benton, Steven J.; Devlin, Mark J.; Dober, Bradley; Fissel, Laura M.; Fukui, Yasuo; Galitzki, Nicholas; Gandilo, Natalie; Klein, Jeffrey; Li, Zhi-Yun; Korotkov, Andrei; Martin, Peter G.; Matthews, Tristan; Moncelsi, Lorenzo; nakamura, fumitaka; Barth Netterfield, Calvin; Novak, Giles; Pascale, Enzo; Poidevin, Frédérick; Savini, Giorgio; Scott, Douglas; Shariff, Jamil; Soler, Juan D.; Thomas, Nicholas; tucker, carole; Tucker, Gregory S.; Ward-Thompson, Derek; BLASTPOL

    2016-06-01

    We present a large-scale combination of near-infrared (near-IR) interstellar polarization data from background starlight, with polarized emission data at sub-millimetric (sub-mm) bands for the Vela C molecular cloud. The sub-mm data were obtained by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) during the 2012 flight in Antartica. The near-IR data consist of more than 6700 detections in the I-band, covering a wide area around the cloud, mostly in the range of visual extinctions between 2 and 16 mag. The main goal was to determine the polarization efficiency ratio Reff , defined as p500/(pI/τV), where p500 is the polarization fraction at 500 μm and optical depths τV are estimated from cataloged near-IR photometry. To ensure that the same column density of material is producing both polarization from emission and extinction, we introduce a new method to select stars that are located in the near-background, the Gaussian-logistic (GL) technique. The polarization efficiency ratio is critically affected by stellar objects with background contamination from the diffuse Galactic material, emphasizing the need for a careful selection. Accounting for the statistical and systematic uncertainties from the GL method, we estimate an average Reff value of 2.4 ± 0.8, which can be used to test dust grain models designed specifically for molecular clouds. Reff appears to be relatively flat as a function of the cloud depth, suggesting that significant grain modification might occur only at higher densities.

  6. The Level 2 research product algorithms for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES

    Directory of Open Access Journals (Sweden)

    P. Baron

    2011-10-01

    Full Text Available This paper describes the algorithms of the level-2 research (L2r processing chain developed for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES. The chain has been developed in parallel to the operational chain for conducting researches on calibration and retrieval algorithms. L2r chain products are available to the scientific community. The objective of version 2 is the retrieval of the vertical distribution of trace gases in the altitude range of 18–90 km. A theoretical error analysis is conducted to estimate the retrieval feasibility of key parameters of the processing: line-of-sight elevation tangent altitudes (or angles, temperature and ozone profiles. While pointing information is often retrieved from molecular oxygen lines, there is no oxygen line in the SMILES spectra, so the strong ozone line at 625.371 GHz has been chosen. The pointing parameters and the ozone profiles are retrieved from the line wings which are measured with high signal to noise ratio, whereas the temperature profile is retrieved from the optically thick line center. The main systematic component of the retrieval error was found to be the neglect of the non-linearity of the radiometric gain in the calibration procedure. This causes a temperature retrieval error of 5–10 K. Because of these large temperature errors, it is not possible to construct a reliable hydrostatic pressure profile. However, as a consequence of the retrieval of pointing parameters, pressure induced errors are significantly reduced if the retrieved trace gas profiles are represented on pressure levels instead of geometric altitude levels. Further, various setups of trace gas retrievals have been tested. The error analysis for the retrieved HOCl profile demonstrates that best results for inverting weak lines can be obtained by using narrow spectral windows.

  7. Innovative wavelengths in endodontic treatment.

    Science.gov (United States)

    Schoop, Ulrich; Kluger, Wolf; Dervisbegovic, Selma; Goharkhay, Kawe; Wernisch, Johann; Georgopoulos, Apostolos; Sperr, Wolfgang; Moritz, Andreas

    2006-07-01

    The sanitation of the root canal system and the adjacent dentin has always been a key requirement for successful endodontics. In recent years, various laser systems have provided a major contribution to this aim, namely the Nd:YAG-, the 810 nm Diode-, the Er:YAG-, and the Er,Cr:YSGG laser. Numerous studies could prove their efficiency within the endodontic procedure. Recently, two new wavelengths have been introduced to the field of oral laser applications: The KTP laser emitting at 532 nm and the 980 nm diode laser. The present in vitro investigation was performed to evaluate the effects of these laser systems focusing on their antibacterial effect in deep layers of dentin and their impact on the root canal dentin. Two-hundred slices of root dentin with a thickness of 1 mm were obtained by longitudinal cuts of freshly extracted human premolars. The samples were steam sterilized and subsequently inoculated with a suspension of either Escherichia coli or Enterococcus faecalis. After the incubation, the samples were randomly assigned to the two different laser systems tested. Each laser group consisted of two different operational settings and a control. The dentinal samples underwent "indirect" laser irradiation through the dentin from the bacteria-free side and were then subjected to a classical quantitative microbiologic evaluation. To assess the temperature increase during the irradiation procedure, additional measurements were carried out using a thermocouple. To assess the impacts on the root canal walls, 20 additional samples underwent laser irradiation at two different settings and were subjected to scanning electron microscopy. Microbiology indicated that both laser systems were capable of significant reductions in both test strains. At an effective output power of 1 W, E. coli was reduced by at least 3 log steps in most of the samples by the tested wavelengths, with the best results for the KTP laser showing complete eradication of E. coli in 75% of the

  8. Wavelength conversion based spectral imaging

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin

    There has been a strong, application driven development of Si-based cameras and spectrometers for imaging and spectral analysis of light in the visible and near infrared spectral range. This has resulted in very efficient devices, with high quantum efficiency, good signal to noise ratio and high...... resolution for this spectral region. Today, an increasing number of applications exists outside the spectral region covered by Si-based devices, e.g. within cleantech, medical or food imaging. We present a technology based on wavelength conversion which will extend the spectral coverage of state of the art...... visible or near infrared cameras and spectrometers to include other spectral regions of interest....

  9. Compact silicon photonic wavelength-tunable laser diode with ultra-wide wavelength tuning range

    Energy Technology Data Exchange (ETDEWEB)

    Kita, Tomohiro, E-mail: tkita@ecei.tohoku.ac.jp; Tang, Rui; Yamada, Hirohito [Graduate School of Engineering, Tohoku University, 6-6-05 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8579 (Japan)

    2015-03-16

    We present a wavelength-tunable laser diode with a 99-nm-wide wavelength tuning range. It has a compact wavelength-tunable filter with high wavelength selectivity fabricated using silicon photonics technology. The silicon photonic wavelength-tunable filter with wide wavelength tuning range was realized using two ring resonators and an asymmetric Mach-Zehnder interferometer. The wavelength-tunable laser diode fabricated by butt-joining a silicon photonic filter and semiconductor optical amplifier shows stable single-mode operation over a wide wavelength range.

  10. Making Displaced Holograms At Two Wavelengths

    Science.gov (United States)

    Witherow, William K.; Ecker, Andreas

    1989-01-01

    Two-wavelength holographic system augmented with pair of prisms to introduce small separation between holograms formed simultaneously at two wavelengths on holographic plate. Principal use in study of flows. Gradients in index of refraction of fluid caused by variations in temperature, concentration, or both. Holography at one wavelength cannot be used to distinguish between two types of variations. Difference between spacings of fringes in photographs reconstructed from holograms taken simultaneously at two different wavelengths manipulated mathematically to determine type of variation.

  11. Biconical fibers as mode and wavelength filters.

    Science.gov (United States)

    Falciai, R; Scheggi, A M

    1989-04-01

    Mode and wavelength filtering characteristics of biconical fibers are examined. A model is considered which simulates the propagation conditions in a bicone made in a slightly overmoded fiber when illuminated at two different wavelengths. The possibility of wavelength selective coupling is evident in view of different applications.

  12. Slope measurement by two-wavelength electronic shearography

    Science.gov (United States)

    Huang, J.-R.; Ford, H. D.; Tatam, R. P.

    1997-06-01

    A technique is presented for the slope measurement of objects using an electronic shearography system. To detect the gradients of an object shape, a laser diode is modulated to produce two wavelengths on successive image frames. These two frames are then subtracted to generate correlation fringes which depict slope variations of the object surface. The theory of this technique is described and measurements of conical, cylindrical, and spherical test objects are presented. Com parisons of experimental results with theoretical data are demonstrated to be in good agreement. The implementation of fringe analysis using phase stepping techniques is also discussed.

  13. Collecting EUV mask images through focus by wavelength tuning

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Kenneth A.; Mochi, Iacopo; Huh, Sungmin

    2009-02-23

    Using an extreme-ultraviolet (EUV) microscope to produce high-quality images of EUV reticles, we have developed a new wavelength tuning method to acquire through-focus data series with a higher level of stability and repeatability than was previously possible. We utilize the chromatic focal-length dependence of a diffractive Fresnel zoneplate objective lens, and while holding the mask sample mechanically still, we tune the wavelength through a narrow range, in small steps. In this paper, we demonstrate the method and discuss the relative advantages that this data collection technique affords.

  14. The SCUBA-2 Cosmology Legacy Survey: ALMA Resolves the Bright-end of the Sub-millimeter Number Counts

    NARCIS (Netherlands)

    Simpson, J. M.; Smail, Ian; Swinbank, A. M.; Chapman, S. C.; Geach, J. E.; Ivison, R. J.; Thomson, A. P.; Aretxaga, I.; Blain, A. W.; Cowley, W. I.; Chen, Chian-Chou; Coppin, K. E. K.; Dunlop, J. S.; Edge, A. C.; Farrah, D.; Ibar, E.; Karim, A.; Knudsen, K. K.; Meijerink, R.; Michałowski, M. J.; Scott, D.; Spaans, M.; van der Werf, P. P.

    We present high-resolution 870 μm Atacama Large Millimeter/sub-millimeter Array (ALMA) continuum maps of 30 bright sub-millimeter sources in the UKIDSS UDS field. These sources are selected from deep, 1 degree2 850 μm maps from the SCUBA-2 Cosmology Legacy Survey, and are representative of the

  15. Observing ice clouds in the submillimeter spectral range: the CloudIce mission proposal for ESA's Earth Explorer 8

    Directory of Open Access Journals (Sweden)

    S. A. Buehler

    2012-07-01

    Full Text Available Passive submillimeter-wave sensors are a way to obtain urgently needed global data on ice clouds, particularly on the so far poorly characterized "essential climate variable" ice water path (IWP and on ice particle size. CloudIce was a mission proposal to the European Space Agency ESA in response to the call for Earth Explorer 8 (EE8, which ran in 2009/2010. It proposed a passive submillimeter-wave sensor with channels ranging from 183 GHz to 664 GHz. The article describes the CloudIce mission proposal, with particular emphasis on describing the algorithms for the data-analysis of submillimeter-wave cloud ice data (retrieval algorithms and demonstrating their maturity. It is shown that we have a robust understanding of the radiative properties of cloud ice in the millimeter/submillimeter spectral range, and that we have a proven toolbox of retrieval algorithms to work with these data. Although the mission was not selected for EE8, the concept will be useful as a reference for other future mission proposals.

  16. A Compact 600 GHz Electronically Tunable Vector Measurement System for Submillimeter Wave Imaging

    Science.gov (United States)

    Dengler, Robert; Maiwald, Frank; Siegel, Peter H.

    2006-01-01

    The design of a complete vector measurement system being tested over 560-635 GHz is presented. The topics include: 1) Current State-of-the-Art in Vector Measurements; 2) Submillimeter Active Imaging Requirements; 3) 600 GHz Vector Measurement System; 4) 450 MHz IF Signal; 5) 450 MHz IF signal @ 1 kHz Res. BW; 6) 450 MHz IF Signal Mixed with Shifted 450 MHz Reference Signal; 7) Reference Signal Offset Generator; 8) Cavity Bandpass Filter; 9) Miniature Multistage Helical Filter; 10) X36 450 MHz Multiplier; 11) 600 GHz Test Setup; 12) 600 GHz Transmit Module; 13) 600 GHz Receive Module; 14) Performance Tests: Amplitude Stability & Dynamic Range; 15) Performance Tests: Phase Stability; 16) Stability at Imaging Bandwidths; 17) Phase Measurement Verification; and 18) The Next Step: Imaging.

  17. The Atacama Large Millimeter/submillimeter Array - from Early Science to Full Operations.

    Science.gov (United States)

    Remijan, Anthony

    2017-06-01

    The Atacama Large Millimeter/Submillimeter Array (ALMA) is now entering its 6th cycle of scientific observations. Starting with Cycle 3, science observations were no longer considered "Early Science" or "best efforts". Cycle 5 is now the third cycle of "steady state" observations and Cycle 7 is advertised to begin ALMA "full science" operations. ALMA Full Science Operations will include all the capabilities that were agreed upon by the international consortium after the ALMA re-baselining effort. In this talk, I will detail the upcoming ALMA Cycle 5 observing capabilities, describe the process of selecting new observing modes for upcoming cycles and provide an update on the status of the ALMA Full Science capabilities.

  18. Estimation of physiological sub-millimeter displacement with CW Doppler radar.

    Science.gov (United States)

    Jia Xu; Xiaomeng Gao; Padasdao, Bryson E; Boric-Lubecke, Olga

    2015-01-01

    Doppler radar physiological sensing has been studied for non-contact detection of vital signs including respiratory and heartbeat rates. This paper presents the first micrometer resolution Wi-Fi band Doppler radar for sub-millimeter physiological displacement measurement. A continuous-wave Doppler radar working at 2.4GHz is used for the measurement. It is intended for estimating small displacements on the body surface resulting from physiological activity. A mechanical mover was used as target, and programmed to conduct sinusoidal motions to simulate pulse motions. Measured displacements were compared with a reference system, which indicates a superior performance in accuracy for having absolute errors less than 10μm, and relative errors below 4%. It indicates the feasibility of highly accurate non-contact monitoring of physiological movements using Doppler radar.

  19. EPR and AFMR of Bi2CuO4 in Submillimeter Wave Region

    Science.gov (United States)

    Ohta, Hitoshi; Yoshida, Kazuhiro; Matsuya, Takashi; Nanba, Takao; Motokawa, Mitsuhiro; Yamada, Kazuyoshi; Endoh, Yasuo; Hosoya, Shoichi

    1992-08-01

    Paramagnetic and antiferromagnetic resonance have been observed in single crystals of Bi2CuO4 in submillimeter wave region using pulsed magnetic fields at temperatures from 4.2 K to 265 K. At the paramagnetic state, g-values have been determined to be g//{=}2.26± 0.01 and g\\bot{=}2.04± 0.01. The angular independent line-widths are 0.37± 0.03 T which is quantitatively explained by the dipole interaction and anisotropic exchange interaction. An antiferromagnetic resonance mode of planer type antiferromagnet has been observed below the Néel temperature and explained by the conventional antiferromagnetic theory.

  20. Submillimeter ionoacoustic range determination for protons in water at a clinical synchrocyclotron

    Science.gov (United States)

    Lehrack, Sebastian; Assmann, Walter; Bertrand, Damien; Henrotin, Sebastien; Herault, Joel; Heymans, Vincent; Vander Stappen, Francois; Thirolf, Peter G.; Vidal, Marie; Van de Walle, Jarno; Parodi, Katia

    2017-09-01

    Proton ranges in water between 145 MeV to 227 MeV initial energy have been measured at a clinical superconducting synchrocyclotron using the acoustic signal induced by the ion dose deposition (ionoacoustic effect). Detection of ultrasound waves was performed by a very sensitive hydrophone and signals were stored in a digital oscilloscope triggered by secondary prompt gammas. The ionoacoustic range measurements were compared to existing range data from a calibrated range detector setup on-site and agreement of better than 1 mm was found at a Bragg peak dose of about 10 Gy for 220 MeV initial proton energy, compatible with the experimental errors. Ionoacoustics has thus the potential to measure the Bragg peak position with submillimeter accuracy during proton therapy, possibly correlated with ultrasound tissue imaging.

  1. A low-cost fabrication method for sub-millimeter wave GaAs Schottky diode

    Science.gov (United States)

    Jenabi, Sarvenaz; Deslandes, Dominic; Boone, Francois; Charlebois, Serge A.

    2017-10-01

    In this paper, a submillimeter-wave Schottky diode is designed and simulated. Effect of Schottky layer thickness on cut-off frequency is studied. A novel microfabrication process is proposed and implemented. The presented microfabrication process avoids electron-beam (e-beam) lithography which reduces the cost. Also, this process provides more flexibility in selection of design parameters and allows significant reduction in the device parasitic capacitance. A key feature of the process is that the Schottky contact, the air-bridges, and the transmission lines, are fabricated in a single lift-off step. This process relies on a planarization method that is suitable for trenches of 1-10 μm deep and is tolerant to end-point variations. The fabricated diode is measured and results are compared with simulations. A very good agreement between simulation and measurement results are observed.

  2. Wavelength modulation spectroscopy of semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, S.E.

    1977-10-01

    The use of modulation spectroscopy to study the electronic properties of solids has been very productive. The construction of a wide range Wavelength Modulation Spectrometer to study the optical properties of solids is described in detail. Extensions of the working range of the spectrometer into the vacuum ultraviolet are discussed. Measurements of the reflectivity and derivative reflectivity spectra of the lead chalcogenides, the chalcopyrite ZnGeP/sub 2/, the layer compounds GaSe and GaS and their alloys, the ferroelectric SbSI, layer compounds SnS/sub 2/ and SnSe/sub 2/, and HfS/sub 2/ were made. The results of these measurements are presented along with their interpretation in terms of band structure calculations.

  3. Multiwavelength digital holography with wavelength-multiplexed holograms and arbitrary symmetric phase shifts.

    Science.gov (United States)

    Tahara, Tatsuki; Otani, Reo; Omae, Kaito; Gotohda, Takuya; Arai, Yasuhiko; Takaki, Yasuhiro

    2017-05-15

    We propose multiwavelength in-line digital holography with wavelength-multiplexed phase-shifted holograms and arbitrary symmetric phase shifts. We use phase-shifting interferometry selectively extracting wavelength information to reconstruct multiwavelength object waves separately from wavelength-multiplexed monochromatic images. The proposed technique obtains systems of equations for real and imaginary parts of multiwavelength object waves from the holograms by introducing arbitrary symmetric phase shifts. Then, the technique derives each complex amplitude distribution of each object wave selectively and analytically by solving the two systems of equations. We formulate the algorithm in the case of an arbitrary number of wavelengths and confirm its validity numerically and experimentally in the cases where the number of wavelengths is two and three.

  4. Observational Approach to Molecular Cloud Evolution with the Submillimeter CI Lines

    Science.gov (United States)

    Oka, T.; Yamamoto, S.; Mt. Fuji Submillimeter-Wave Telescope Group

    Neutral carbon atoms (CI) play important role both in chemistry and cooling processes of interstellar molecular clouds. It is thus crucial to explore its large area distribution to investigate formation processes and thermal balance of molecular clouds. We have constructed a 1.2 m submillimeter-wave telescope at the summit of Mt.Fuji. The telescope was designed for the exclusive use of surveying molecular clouds in two submillimeter CI lines, 3P1--3P0 (492 GHz) and 3P2--3P1 (809 GHz), of atomic carbon. It has been operated successfully during 4 observing seasons since July 1998 in a remote way from the Hongo campus of the University of Tokyo. We have already revealed large-scale CI 492 GHz distributions of many giant molecular clouds, including Orion MC, Taurus MC, DR15, DR21, NGC2264, M17, W3, W44, W51, Rosette MC, covering more than 40 square degrees of the sky. The distribution of CI 492 GHz emission is found to be different from those of the 13CO or C18O emission in some clouds. We found the spatial order of C+/CO/C from UV sources. This is the general property of the cloud illuminated by intense UV radiation, whereas it is apparently inconsistent with the standard photodissociation region (PDR) picture. We also found CI-rich areas (C/CO˜1) in several dark clouds without strong UV sources. These results are discussed in relation to formation processes of molecular clouds and dense cloud cores.

  5. CORRELATIONS IN THE (SUB)MILLIMETER BACKGROUND FROM ACT Multiplication-Sign BLAST

    Energy Technology Data Exchange (ETDEWEB)

    Hajian, Amir; Battaglia, Nick; Bond, J. Richard [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Viero, Marco P.; Bock, James J. [California Institute of Technology, Pasadena, CA 91125 (United States); Addison, Graeme [Department of Astrophysics, Oxford University, Oxford, OX1 3RH (United Kingdom); Aguirre, Paula [Departamento de Astronomia y Astrofisica, Facultad de Fisica, Pontificia Universidad Catolica, Casilla 306, Santiago 22 (Chile); Appel, John William; Duenner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W.; Hincks, Adam D. [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); Das, Sudeep; Dunkley, Joanna [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Devlin, Mark J.; Dicker, Simon R. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Hughes, John P. [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854-8019 (United States); Halpern, Mark [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Hasselfield, Matthew [Laboratoire APC, Universite Paris Diderot, 75205 Paris (France); Hilton, Matt [Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, University of KwaZulu-Natal, Durban 4041 (South Africa); and others

    2012-01-01

    We present measurements of the auto- and cross-frequency correlation power spectra of the cosmic (sub)millimeter background at 250, 350, and 500 {mu}m (1200, 860, and 600 GHz) from observations made with the Balloon-borne Large Aperture Submillimeter Telescope (BLAST); and at 1380 and 2030 {mu}m (218 and 148 GHz) from observations made with the Atacama Cosmology Telescope (ACT). The overlapping observations cover 8.6 deg{sup 2} in an area relatively free of Galactic dust near the south ecliptic pole. The ACT bands are sensitive to radiation from the cosmic microwave background, to the Sunyaev-Zel'dovich effect from galaxy clusters, and to emission by radio and dusty star-forming galaxies (DSFGs), while the dominant contribution to the BLAST bands is from DSFGs. We confirm and extend the BLAST analysis of clustering with an independent pipeline and also detect correlations between the ACT and BLAST maps at over 25{sigma} significance, which we interpret as a detection of the DSFGs in the ACT maps. In addition to a Poisson component in the cross-frequency power spectra, we detect a clustered signal at 4{sigma}, and using a model for the DSFG evolution and number counts, we successfully fit all of our spectra with a linear clustering model and a bias that depends only on redshift and not on scale. Finally, the data are compared to, and generally agree with, phenomenological models for the DSFG population. This study demonstrates the constraining power of the cross-frequency correlation technique to constrain models for the DSFGs. Similar analyses with more data will impose tight constraints on future models.

  6. Imaging the environment of a z = 6.3 submillimeter galaxy with SCUBA-2

    Energy Technology Data Exchange (ETDEWEB)

    Robson, E. I.; Holland, W. S. [United Kingdom Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Ivison, R. J. [European Space Observatory, Karl Schwarzschild Strasse 2, D-85748 Garching (Germany); Smail, Ian [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Geach, J. E. [Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Gibb, A. G. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Riechers, D. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Ade, P. A. R. [Astronomy and Instrumentation Group, Cardiff University, Cardiff, Wales CF10 3XQ (United Kingdom); Bintley, D. [Joint Astronomy Centre, 660 North Ahoku Place, University Park, Hilo, HI 96720 (United States); Bock, J. [Jet Propulsion Laboratory, National Aeronautics and Space Administration, Pasadena, CA 91109 (United States); Chapin, E. L. [XMM-Newton Science Operations Centre, European Space Astronomy Centre, Apartado 79, E-28691 Villaneueva de la Canada, Madrid (Spain); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University, Coburg Road, Halifax B3H 1A6 (Canada); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy, 389 UCB, University of Colorado, Boulder, CO 80309 (United States); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Dunlop, J. S. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Farrah, D., E-mail: rob.ivison@gmail.com [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); and others

    2014-09-20

    We describe a search for submillimeter emission in the vicinity of one of the most distant, luminous galaxies known, HerMES FLS3, at z = 6.34, exploiting it as a signpost to a potentially biased region of the early universe, as might be expected in hierarchical structure formation models. Imaging to the confusion limit with the innovative, wide-field submillimeter bolometer camera, SCUBA-2, we are sensitive to colder and/or less luminous galaxies in the surroundings of HFLS3. We use the Millennium Simulation to illustrate that HFLS3 may be expected to have companions if it is as massive as claimed, but find no significant evidence from the surface density of SCUBA-2 galaxies in its vicinity, or their colors, that HFLS3 marks an overdensity of dusty, star-forming galaxies. We cannot rule out the presence of dusty neighbors with confidence, but deeper 450 μm imaging has the potential to more tightly constrain the redshifts of nearby galaxies, at least one of which likely lies at z ≳ 5. If associations with HFLS3 can be ruled out, this could be taken as evidence that HFLS3 is less biased than a simple extrapolation of the Millennium Simulation may imply. This could suggest either that it represents a rare short-lived, but highly luminous, phase in the evolution of an otherwise typical galaxy, or that this system has suffered amplification due to a foreground gravitational lens and so is not as intrinsically luminous as claimed.

  7. Diffusion in and around alginate and chitosan films with embedded sub-millimeter voids

    Energy Technology Data Exchange (ETDEWEB)

    Patra, Subhajit; Bal, Dharmendra Kumar; Ganguly, Somenath, E-mail: snganguly@che.iitkgp.ernet.in

    2016-02-01

    Hydrogel scaffolds from biopolymers have potential use in the controlled release of drugs, and as 3-D structure for the formation of tissue matrix. This article describes the solute release behavior of alginate and chitosan films with embedded voids of sub-millimeter dimensions. Nitrogen gas was bubbled in a fluidic arrangement to generate bubbles, prior to the crosslinking. The crosslinked gel was dried in a vacuum oven, and subsequently, soaked in Vitamin B-12 solution. The dimensions of the voids immediately after the cross-linking of gel, and also after complete drying were obtained using a digital microscope and scanning electron microscope respectively. The porosity of the gel was measured gravimetrically. The release of Vitamin B-12 in PBS buffer on a shaker was studied. The release experiments were repeated at an elevated temperature of 37 °C in the presence of lysozyme. The diffusion coefficient within the gel layer and the mass transfer coefficient at the interface with the bulk-liquid were estimated using a mathematical model. For comparison, the experiment was repeated with a film that does not have any embedded void. The enhancement in diffusion coefficient due to the presence of voids is discussed in this article. - Highlights: • Formation of sub-millimeter voids in biopolymer films using fluidic arrangement • The retention of self-assembled bubbles in films after crosslinking, and drying • The enhancement observed in release of model drug with introduction of voids • The diffusion coefficients in and around biopolymer films from model regression • Use of classical model in explaining release profiles from dual porosity media.

  8. An ALMA survey of submillimeter galaxies in the extended Chandra deep field south: The redshift distribution and evolution of submillimeter galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J. M.; Swinbank, A. M.; Smail, Ian; Alexander, D. M.; Danielson, A. L. R.; Thomson, A. P. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Brandt, W. N. [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Bertoldi, F.; Karim, A. [Argelander-Institute for Astronomy, Bonn University, Auf dem Hügel 71, D-53121 Bonn (Germany); De Breuck, C. [European Southern Observatory, Karl-Schwarzschild Straße, D-85748 Garching bei München (Germany); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 3J5 (Canada); Coppin, K. E. K. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Da Cunha, E.; Hodge, J. A.; Schinnerer, E. [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Dannerbauer, H. [Universität Wien, Institut für Astrophysik, Türkenschanzstraße 17, A-1180 Wien (Austria); Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Ivison, R. J. [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Knudsen, K. K. [Department of Earth and Space Science, Onsala Space Observatory, Chalmers University of Technology, SE-43992 Onsala (Sweden); Poggianti, B. M., E-mail: j.m.simpson@dur.ac.uk [INAF-Astronomical Observatory of Padova, I-35122 Padova (Italy); and others

    2014-06-20

    We present the first photometric redshift distribution for a large sample of 870 μm submillimeter galaxies (SMGs) with robust identifications based on observations with ALMA. In our analysis we consider 96 SMGs in the Extended Chandra Deep Field South, 77 of which have 4-19 band photometry. We model the SEDs for these 77 SMGs, deriving a median photometric redshift of z {sub phot} = 2.3 ± 0.1. The remaining 19 SMGs have insufficient photometry to derive photometric redshifts, but a stacking analysis of Herschel observations confirms they are not spurious. Assuming that these SMGs have an absolute H-band magnitude distribution comparable to that of a complete sample of z ∼ 1-2 SMGs, we demonstrate that they lie at slightly higher redshifts, raising the median redshift for SMGs to z {sub phot} = 2.5 ± 0.2. Critically we show that the proportion of galaxies undergoing an SMG-like phase at z ≥ 3 is at most 35% ± 5% of the total population. We derive a median stellar mass of M {sub *} = (8 ± 1) × 10{sup 10} M {sub ☉}, although there are systematic uncertainties of up to 5 × for individual sources. Assuming that the star formation activity in SMGs has a timescale of ∼100 Myr, we show that their descendants at z ∼ 0 would have a space density and M{sub H} distribution that are in good agreement with those of local ellipticals. In addition, the inferred mass-weighted ages of the local ellipticals broadly agree with the look-back times of the SMG events. Taken together, these results are consistent with a simple model that identifies SMGs as events that form most of the stars seen in the majority of luminous elliptical galaxies at the present day.

  9. MULTIPLE OBJECTS

    Directory of Open Access Journals (Sweden)

    A. A. Bosov

    2015-04-01

    Full Text Available Purpose. The development of complicated techniques of production and management processes, information systems, computer science, applied objects of systems theory and others requires improvement of mathematical methods, new approaches for researches of application systems. And the variety and diversity of subject systems makes necessary the development of a model that generalizes the classical sets and their development – sets of sets. Multiple objects unlike sets are constructed by multiple structures and represented by the structure and content. The aim of the work is the analysis of multiple structures, generating multiple objects, the further development of operations on these objects in application systems. Methodology. To achieve the objectives of the researches, the structure of multiple objects represents as constructive trio, consisting of media, signatures and axiomatic. Multiple object is determined by the structure and content, as well as represented by hybrid superposition, composed of sets, multi-sets, ordered sets (lists and heterogeneous sets (sequences, corteges. Findings. In this paper we study the properties and characteristics of the components of hybrid multiple objects of complex systems, proposed assessments of their complexity, shown the rules of internal and external operations on objects of implementation. We introduce the relation of arbitrary order over multiple objects, we define the description of functions and display on objects of multiple structures. Originality.In this paper we consider the development of multiple structures, generating multiple objects.Practical value. The transition from the abstract to the subject of multiple structures requires the transformation of the system and multiple objects. Transformation involves three successive stages: specification (binding to the domain, interpretation (multiple sites and particularization (goals. The proposed describe systems approach based on hybrid sets

  10. Wavelength Gated Dynamic Covalent Chemistry.

    Science.gov (United States)

    Frisch, Hendrik; Marschner, David; Goldmann, Anja; Barner-Kowollik, Christopher

    2017-10-24

    Precise control of chemical reactions constitutes the foundation of synthesis. Classically, judicious functional group choice as well as external factors such as temperature and catalysts are used to exert control, yet the recent renaissance of light as a medium to direct chemical synthesis points to the advent of a new era in enabling chemical selectivity. Light-guided reactions not only offer precise temporal and spatial control, yet critically allow to selectively address highly specific reaction channels gated by wavelength and intensity, resulting in a unique level of reaction control via covalent bonds that can be made and unmade by finely regulated photonic fields. Photoreversible cycloadditions are the most promising candidates to seize the outlined potential upon selective cyclisation and cycloreversion, yet are today still far from fulfilling these expectations. Herein, we critically explore the current challenges in the application of photoreversible cycloadditions and discuss the steps necessary to seize their potential in molecular biology, biomimetic systems, 3D laser lithographic processes and advanced soft matter materials with reprogrammable and self-healing properties. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. All-optical wavelength-shifting technologies

    DEFF Research Database (Denmark)

    Jørgensen, Carsten; Mikkelsen, Benny; Danielsen, Søren Lykke

    1995-01-01

    State-of-the-art results for interferometric wavelength converters for WDM fiber networks have been presented. The interferometric converters are capable of high speed (10 Gbit/s), polarisation and wavelength independent (within 30 nn) wavelength conversion. In addition they offer unique features...... such as extinction ratio improvement and spectral cleaning. The 1-dB input power dynamic range is around 4 dB but can be increased to 8 dB by a simple control scheme...

  12. Standard achromatic perimetry, short wavelength automated perimetry, and frequency doubling technology for detection of glaucoma damage

    NARCIS (Netherlands)

    Soliman, Mohamed A. E.; de Jong, Leo A. M. S.; Ismaeil, Al-Araby A.; van den Berg, Thomas J. T. P.; de Smet, Marc D.

    2002-01-01

    Objective: Reevaluation of the relationship between short wavelength automated perimetry (SWAP), standard achromatic perimetry (SAP), and frequency doubling technology (FDT) in glaucoma and ocular hypertensive patients and in glaucoma suspects. Design: Prospective comparative observational study.

  13. Far-Infrared and Submillimeter Emission from Galactic and Extragalactic Photodissociation Regions

    Science.gov (United States)

    Kaufman, Michael J.; Wolfire, Mark G.; Hollenbach, David J.; Luhman, Michael L.

    1999-12-01

    Photodissociation region (PDR) models are computed over a wide range of physical conditions, from those appropriate to giant molecular clouds illuminated by the interstellar radiation field to the conditions experienced by circumstellar disks very close to hot massive stars. These models use the most up-to-date values of atomic and molecular data, the most current chemical rate coefficients, and the newest grain photoelectric heating rates, which include treatments of small grains and large molecules. In addition, we examine the effects of metallicity and cloud extinction on the predicted line intensities. Results are presented for PDR models with densities over the range n=101-107 cm-3 and for incident far-ultraviolet radiation fields over the range G0=10-0.5-106.5 (where G0 is the far-ultravioliet [FUV] flux in units of the local interstellar value), for metallicities Z=1 and 0.1 times the local Galactic value, and for a range of PDR cloud sizes. We present line strength and/or line ratio plots for a variety of useful PDR diagnostics: [C II] 158 μm, [O I] 63 μm and 145 μm, [C I] 370 μm and 609 μm, CO J=1-0, J=2-1, J=3-2, J=6-5, and J=15-14, as well as the strength of the far-infrared continuum. These plots will be useful for the interpretation of Galactic and extragalactic far-infrared and submillimeter spectra observable with the Infrared Space Observatory (ISO), the Stratospheric Observatory for Infrared Astronomy, the Submillimeter Wave Astronomy Satellite, the Far Infrared and Submillimeter Telescope, and other orbital and suborbital platforms. As examples, we apply our results to ISO and ground-based observations of M82, NGC 278, and the Large Magellanic Cloud. Our comparison of the conditions in M82 and NGC 278 show that both the gas density and FUV flux are enhanced in the starburst nucleus of M82 compared with those in the normal spiral NGC 278. We model the high [C II]/CO ratio observed in the 30 Doradus region of the LMC and find that it can be

  14. Pragmatic Objectivity

    OpenAIRE

    Michele Marsonet

    2014-01-01

    Nicholas Rescher writes that “objectivity is not something we infer from the data; it is something we must presuppose. It is something that we postulate or presume from the very outset of our dealings with people’s claims about the world’s facts”. Such definition is just the opposite of objectivity conceived of in classical terms, but it cannot be equated with an idealistic viewpoint according to which objectivity is something that our mind simply creates in the process of reflection. It is, ...

  15. Searching for new green wavelength shifters in polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    Pla-Dalmau, A.; Foster, G.W.; Zhang, G.

    1993-12-01

    A series of commercially available fluorescent compounds was tested as wavelength shifters in polystyrene for the tile/fiber SDC calorimeter. The objective was to find a green-fluorescing compound with short decay time (3--7 ns). Transmittance, fluorescence, and decay time measurements were performed in order to characterize each compound in polystyrene. These samples were also studies for radiation-induced damage.

  16. THE BEHAVIOR OF THE PITCH ANGLE OF SPIRAL ARMS DEPENDING ON OPTICAL WAVELENGTH

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-García, Eric E.; Puerari, Ivânio; Rosales-Ortega, F. F.; Luna, A. [Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla, Pue. (Mexico); González-Lópezlira, Rosa A. [Centro de Radioastronomía y Astrofísica, UNAM, Campus Morelia, Michoacán, México, C.P. 58089 (Mexico); Fuentes-Carrera, Isaura, E-mail: ericmartinez@inaoep.mx [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, U. P. Adolfo López Mateos, Zacatenco, 07730 México, D.F. (Mexico)

    2014-09-20

    Based on integral field spectroscopy data from the CALIFA survey, we investigate the possible dependence of spiral arm pitch angle with optical wavelength. For three of the five studied objects, the pitch angle gradually increases at longer wavelengths. This is not the case for two objects where the pitch angle remains constant. This result is confirmed by the analysis of SDSS data. We discuss the possible physical mechanisms to explain this phenomenon, as well as the implications of the results.

  17. Submillimeter residual losses in high-Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David [Univ. of California, Berkeley, CA (United States)

    1993-09-01

    Bolometry was used obtain accurate submillimeter residual loss data for epitaxial films of YBa2Cu3O7 (YBCO), Tl2Ca2Ba2Cu3O10, Tl2CaBa2Cu2O8 (TCBCO), and Ba0.6K0.4BiO3 (BKBO). We were able to fit the absorptivity measured for Nb films to an Eliashberg strong coupling calculation; excellent agreement resulted between parameters from best fits and measured Residual Resistivity Ratio. Microwave surface resistance measurements made on the same YBCO and TCBCO films are in excellent agreement with submillimeter measurements. Absorptivities for all YBCO films studied are qualitatively similar, increasing smoothly with frequency, with no gap-like features below the well known absorption edge at 450 cm-1. Losses in YBCO films were fit to a weakly coupled grain model for the a-b plane conductivity. Strong phonon structure was observed in TCBCO films between 60 and 700 cm-1 (2 THz and 23 THz); these losses could not be fitted to the simple weakly coupled grain model, in contrast to the case for other high-Tc superconductors where phonon structure observed in ceramics are is absent in epitaxial oriented films and crystals because of electronic screening due to high conductivity of a-b planes. Absorptivity data for the BKBO films all show a strong absorption onset near the BCS tunneling gap of 3.5 kBTc. Comparison with strong coupling Eliashberg predictions and of a Kramers-Kronig analysis indicate that the absorption onset is consistent with a superconducting energy gap. Effects of magnetic field on residual losses in YBCO films show a resonant absorption feature in vicinity of predicted

  18. Trusted Objects

    Energy Technology Data Exchange (ETDEWEB)

    CAMPBELL,PHILIP L.; PIERSON,LYNDON G.; WITZKE,EDWARD L.

    1999-10-27

    In the world of computers a trusted object is a collection of possibly-sensitive data and programs that can be allowed to reside and execute on a computer, even on an adversary's machine. Beyond the scope of one computer we believe that network-based agents in high-consequence and highly reliable applications will depend on this approach, and that the basis for such objects is what we call ''faithful execution.''

  19. A Submillimeter Perspective on the Goods Fields. II. The High Radio Power Population in the Goods-N

    Science.gov (United States)

    Barger, A. J.; Cowie, L. L.; Owen, F. N.; Hsu, L.-Y.; Wang, W.-H.

    2017-01-01

    We use ultradeep 20 cm data from the Karl G. Jansky Very Large Array and 850 μm data from SCUBA-2 and the Submillimeter Array of an 124 arcmin2 region of the Chandra Deep Field-north to analyze the high radio power ({P}20{cm}> {10}31 erg s-1 Hz-1) population. We find that 20 (42 ± 9%) of the spectroscopically identified z> 0.8 sources have consistent star formation rates (SFRs) inferred from both submillimeter and radio observations, while the remaining sources have lower (mostly undetected) submillimeter fluxes, suggesting that active galactic nucleus (AGN) activity dominates the radio power in these sources. We develop a classification scheme based on the ratio of submillimeter flux to radio power versus radio power and find that it agrees with AGN and star-forming galaxy classifications from Very Long Baseline Interferometry. Our results provide support for an extremely rapid drop in the number of high SFR galaxies above about a thousand solar masses per year (Kroupa initial mass function) and for the locally determined relation between X-ray luminosity and radio power for star-forming galaxies applying at high redshifts and high radio powers. We measure far-infrared (FIR) luminosities and find that some AGNs lie on the FIR-radio correlation, while others scatter below. The AGNs that lie on the correlation appear to do so based on their emission from the AGN torus. We measure a median radio size of 1.″0 ± 0.3 for the star-forming galaxies. The radio sizes of the star-forming galaxies are generally larger than those of the AGNs. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.

  20. Wavelength Margin Analysis in Advanced Collinear Holography

    Science.gov (United States)

    Horimai, Hideyoshi; Tan, Xiaodi; Li, Jun; Suzuki, Kenji

    2005-05-01

    The wavelength margin of advanced collinear holography, which utilizes co-axially aligned information and reference beams modulated by the same spatial light modulator simultaneously, is analyzed and compared that of conventional 2-axis holography. Being the large wavelength margin, a laser diode as a light source of the holography is possible.

  1. The Hawaii SCUBA-2 Lensing Cluster Survey: Radio-detected Submillimeter Galaxies in the HST Frontier Fields

    Science.gov (United States)

    Hsu, Li-Yen; Desai, Vandana; Murphy, Eric J.; Cowie, Lennox L.; Heywood, Ian; Momjian, Emmanuel; Barger, Amy J.; Smail, Ian

    2017-05-01

    In this second paper of the Hawaii SCUBA-2 Lensing Cluster Survey series, we cross-match SCUBA-2 maps with 3 and 6 GHz images from the Janksy-VLA Frontier Fields Legacy Survey for three cluster fields, MACS J0416.1-2403, MACS J0717.5+3745, and MACS J1149.5+2223. Within the HST coverage, 14 out of 44 850 μm sources have 3 GHz counterparts, five of which are also detected at 6 GHz. The 850 μm flux densities of these detected sources span from 0.7 to 4.4 mJy after correcting for lensing amplification. The median redshift of the sample is z={1.28}-0.09+0.07, much lower than the typical redshifts (z = 2-3) of brighter submillimeter galaxies (SMGs) in the literature. In addition, we find that our sources have lower dust temperatures than those of the brighter SMGs. This is also confirmed by an analysis of the ratio between infrared star-formation rate and 850 μm flux density. However, these 14 sources may not represent the general submillimeter population at the same flux range, given that the SCUBA-2 sources without radio counterparts are likely at higher redshifts. Detection of these sources would require deeper radio images or submillimeter interferometry.

  2. Paving the way to simultaneous multi-wavelength astronomy

    Science.gov (United States)

    Middleton, M. J.; Casella, P.; Gandhi, P.; Bozzo, E.; Anderson, G.; Degenaar, N.; Donnarumma, I.; Israel, G.; Knigge, C.; Lohfink, A.; Markoff, S.; Marsh, T.; Rea, N.; Tingay, S.; Wiersema, K.; Altamirano, D.; Bhattacharya, D.; Brandt, W. N.; Carey, S.; Charles, P.; Díaz Trigo, M.; Done, C.; Kotze, M.; Eikenberry, S.; Fender, R.; Ferruit, P.; Fürst, F.; Greiner, J.; Ingram, A.; Heil, L.; Jonker, P.; Komossa, S.; Leibundgut, B.; Maccarone, T.; Malzac, J.; McBride, V.; Miller-Jones, J.; Page, M.; Rossi, E. M.; Russell, D. M.; Shahbaz, T.; Sivakoff, G. R.; Tanaka, M.; Thompson, D. J.; Uemura, M.; Uttley, P.; van Moorsel, G.; van Doesburgh, M.; Warner, B.; Wilkes, B.; Wilms, J.; Woudt, P.

    2017-11-01

    Whilst astronomy as a science is historically founded on observations at optical wavelengths, studying the Universe in other bands has yielded remarkable discoveries, from pulsars in the radio, signatures of the Big Bang at submm wavelengths, through to high energy emission from accreting, gravitationally-compact objects and the discovery of gamma-ray bursts. Unsurprisingly, the result of combining multiple wavebands leads to an enormous increase in diagnostic power, but powerful insights can be lost when the sources studied vary on timescales shorter than the temporal separation between observations in different bands. In July 2015, the workshop ;Paving the way to simultaneous multi-wavelength astronomy; was held as a concerted effort to address this at the Lorentz Center, Leiden. It was attended by 50 astronomers from diverse fields as well as the directors and staff of observatories and spaced-based missions. This community white paper has been written with the goal of disseminating the findings of that workshop by providing a concise review of the field of multi-wavelength astronomy covering a wide range of important source classes, the problems associated with their study and the solutions we believe need to be implemented for the future of observational astronomy. We hope that this paper will both stimulate further discussion and raise overall awareness within the community of the issues faced in a developing, important field.

  3. Fashion Objects

    DEFF Research Database (Denmark)

    Andersen, Bjørn Schiermer

    2009-01-01

    This article attempts to create a framework for understanding modern fashion phenomena on the basis of Durkheim's sociology of religion. It focuses on Durkheim's conception of the relation between the cult and the sacred object, on his notion of 'exteriorisation', and on his theory of the social...... symbol in an attempt to describe the peculiar attraction of the fashion object and its social constitution. However, Durkheim's notions of cult and ritual must undergo profound changes if they are to be used in an analysis of fashion. The article tries to expand the Durkheimian cult, radically enlarging...... it without totally dispersing it; depicting it as held together exclusively by the sheer 'force' of the sacred object. Firstly, the article introduces the themes and problems surrounding Durkheim's conception of the sacred. Next, it briefly sketches an outline of fashion phenomena in Durkheimian categories...

  4. Submillimeter Detection of the van der Waals Stretching Vibration of the Ar-CO Complex

    Science.gov (United States)

    Gendriesch, R.; Pak, I.; Lewen, F.; Surin, L.; Roth, D. A.; Winnewisser, G.

    1999-07-01

    With the Cologne submillimeter-wave supersonic jet spectrometer, we extended molecular jet spectroscopy with backward wave oscillators up to frequencies of about 600 GHz. For the first time, the van der Waals stretching vibration of the Ar-CO molecular complex was detected in direct absorption. We measured 13 ro-vibrational transitions (Kvstretch = 1 ← 0, Ka = 0 ← 0) in the frequency range from 528 to 600 GHz and additionally the two R(3) K doublet (Ka = 4 ← 3) pure rotational transitions at 447 GHz with an accuracy of about 200 kHz. The ro-vibrational transitions were assigned and fitted within experimental accuracy to a simple Hamiltonian taking into account the Coriolis interaction between the stretching and bending states, i.e., between vstretch = 1, Ka = 0, and vbend = 1, Ka = 1. The intensity of the transitions in the van der Waals stretching mode was estimated to be a factor of 5-10 less than that in the bending mode of Ar-CO.

  5. T-shaped emitter metal heterojunction bipolar transistors for submillimeter wave applications

    Science.gov (United States)

    Fung, Andy; Samoska, Lorene; Velebir, Jim; Siege, Peter; Rodwell, Mark; Paidi, Vamsi; Griffth, Zach; Urteaga, Miguel; Malik, Roger

    2004-01-01

    We report on the development of submillimeter wave transistors at JPL. The goal of the effort is to produce advance-reliable high frequency and high power amplifiers, voltage controlled oscillators, active multipliers, and high-speed mixed-signal circuits for space borne applications. The technology in development to achieve this is based on the Indium Phosphide (InP) Heterojunction Bipolar Transistor (HBT). The HBT is well suited for high speed, high power and uniform (across wafer) performance, due to the ability to tailor the material structure that electrons traverse through by well-controlled epitaxial growth methods. InP with its compatible lattice matched alloys such as indium gallium arsenide (InGaAs) and indium aluminium arsenide (InAlAs) provides for high electron velocities and high voltage breakdown capabilities. The epitaxial methods for this material system are fairly mature, however the implementation of high performance and reliable transistors are still under development by many laboratories. Our most recently fabricated, second generation mesa HBTs at JPL have extrapolated current gain cutoff frequency (FJ of 142GHz and power gain cutoff frequency (Fm,) of approximately 160GHz. This represents a 13% and 33% improvement of Ft and F, respectively, compared to the first generation mesa HBTs [l]. Analysis based on the University of California, Santa Barbara (UCSB) device model, RF device characteristics can be significantly improved by reducing base contact resistance and base metal contact width. We will describe our effort towards increasing transistor performance and yield.

  6. Velocity-resolved Hot Water Emission Detected toward HL Tau with the Submillimeter Array

    Science.gov (United States)

    Kristensen, Lars E.; Brown, Joanna M.; Wilner, David; Salyk, Colette

    2016-05-01

    Using the Submillimeter Array (SMA) on Mauna Kea, the {{{H}}}216{{O}} {10}{2,9}-9{}{3,6} transition ({E}{{up}} = 1863 K) at 321.2 GHz has been detected toward the embedded low-mass protostar HL Tau. The line centroid is blueshifted by 20 km s-1 with respect to the source velocity, and it has a FWHM of 25 km s-1. The emission is tentatively resolved and extends ˜3″-4″ over the sky (˜2 beams), or ˜500 au at the distance of Taurus. The velocity offset, and to a lesser degree the spatial extent of the emission, show that the line originates in the protostellar jet or wind. This result suggests that at least some water emission observed with Herschel and Spitzer toward embedded sources, and perhaps also disk sources, contains a wind or jet component, which is crucial for interpreting these data. These pathfinder observations done with the SMA open a new window into studying the origin of water emission with e.g., ALMA, thus providing new insights into where water is in protostellar systems.

  7. Controlled production of sub-millimeter liquid core hydrogel capsules for parallelized 3D cell culture.

    Science.gov (United States)

    Doméjean, Hugo; de la Motte Saint Pierre, Mathieu; Funfak, Anette; Atrux-Tallau, Nicolas; Alessandri, Kevin; Nassoy, Pierre; Bibette, Jérôme; Bremond, Nicolas

    2016-12-20

    Liquid core capsules having a hydrogel membrane are becoming a versatile tool for three-dimensional culture of micro-organisms and mammalian cells. Making sub-millimeter capsules at a high rate, via the breakup of a compound jet in air, opens the way to high-throughput screening applications. However, control of the capsule size monodispersity, especially required for quantitative bioassays, was still lacking. Here, we report how the understanding of the underlying hydrodynamic instabilities that occur during the process can lead to calibrated core-shell bioreactors. The requirements are: i) damping the shear layer instability that develops inside the injector arising from the co-annular flow configuration of liquid phases having contrasting viscoelastic properties; ii) controlling the capillary instability of the compound jet by superposing a harmonic perturbation onto the shell flow; iii) avoiding coalescence of drops during jet fragmentation as well as during drop flight towards the gelling bath; iv) ensuring proper engulfment of the compound drops into the gelling bath for building a closed hydrogel shell. We end up with the creation of numerous identical compartments in which cells are able to form multicellular aggregates, namely spheroids. In addition, we implement an intermediate composite hydrogel layer, composed of alginate and collagen, allowing cell adhesion and thus the formation of epithelia or monolayers of cells.

  8. Simultaneous retrievals of temperature and volume mixing ratio constituents from nonoxygen odin submillimeter radiometer bands.

    Science.gov (United States)

    Baron, P; Merino, F; Murtagh, D

    2001-11-20

    We present the retrieval of temperature and O(3) volume mixing ratio profiles in the middle atmosphere from a single strong O(3) line. We performed the study using simulated limb-sounding measurements in the frame of the submillimeter radiometer (SMR) instrument that will be carried by the Odin satellite that is due to be launched in early 2001. This study is interesting for the Odin SMR data analysis because we first provide additional temperature measurements, and second reduce significantly the O(3) retrieval error that is due to the temperature and pressure uncertainties. Nonlinear retrievals are performed to retrieve the O(3), CO, H(2)O, and temperature profiles simultaneously from the spectral band 576.27-576.67 GHz. The pressure profile is deduced from the hydrostatic equilibrium equation after each iteration. Temperature and O(3) can be retrieved throughout the stratosphere from 15-50 and 20-50 km, respectively, with a vertical resolution of 3 km. The altitude domain corresponds to the parts of the atmosphere where the signal intensity saturates in some spectrometer channels. A total error of 4-6 K has been found in the temperature profile, mainly because of the instrumental thermal noise and to a lesser extent the calibration. The total error in the O(3) profile is 5-10% and is dominated by the O(3) line-broadening parameter. The total error on the retrieved pressure profile is 2-10% because of the errors in calibration and reference pressure.

  9. Optical fiber sensors-based temperature distribution measurement in ex vivo radiofrequency ablation with submillimeter resolution

    Science.gov (United States)

    Macchi, Edoardo Gino; Tosi, Daniele; Braschi, Giovanni; Gallati, Mario; Cigada, Alfredo; Busca, Giorgio; Lewis, Elfed

    2014-11-01

    Radiofrequency thermal ablation (RFTA) induces a high-temperature field in a biological tissue having steep spatial (up to 6°C/mm) and temporal (up to 1°C/s) gradients. Applied in cancer care, RFTA produces a localized heating, cytotoxic for tumor cells, and is able to treat tumors with sizes up to 3 to 5 cm in diameter. The online measurement of temperature distribution at the RFTA point of care has been previously carried out with miniature thermocouples and optical fiber sensors, which exhibit problems of size, alteration of RFTA pattern, hysteresis, and sensor density worse than 1 sensor/cm. In this work, we apply a distributed temperature sensor (DTS) with a submillimeter spatial resolution for the monitoring of RFTA in porcine liver tissue. The DTS demodulates the chaotic Rayleigh backscattering pattern with an interferometric setup to obtain the real-time temperature distribution. A measurement chamber has been set up with the fiber crossing the tissue along different diameters. Several experiments have been carried out measuring the space-time evolution of temperature during RFTA. The present work showcases the temperature monitoring in RFTA with an unprecedented spatial resolution and is exportable to in vivo measurement; the acquired data can be particularly useful for the validation of RFTA computational models.

  10. Submillimeter Array 12CO (2-1) Imaging of the NGC 6946 Giant Molecular Clouds

    Science.gov (United States)

    Wu, Ya-Lin; Sakamoto, Kazushi; Pan, Hsi-An

    2017-04-01

    We present a 12CO (2-1) mosaic map of the spiral galaxy NGC 6946 by combining data from the Submillimeter Array and the IRAM 30 m telescope. We identify 390 giant molecular clouds (GMCs) from the nucleus to 4.5 kpc in the disk. GMCs in the inner 1 kpc are generally more luminous and turbulent, some of which have luminosities >106 K km s-1 pc2 and velocity dispersions >10 km s-1. Large-scale bar-driven dynamics likely regulate GMC properties in the nuclear region. Similar to the Milky Way and other disk galaxies, GMC mass function of NGC 6946 has a shallower slope (index > -2) in the inner region, and a steeper slope (index outer region. This difference in mass spectra may be indicative of different cloud formation pathways: gravitational instabilities might play a major role in the nuclear region, while cloud coalescence might be dominant in the outer disk. Finally, the NGC 6946 clouds are similar to those in M33 in terms of statistical properties, but they are generally less luminous and turbulent than the M51 clouds.

  11. Demonstration of a phase-lockable microwave to submillimeter wave sweeper

    Science.gov (United States)

    Waltman, Steve B.; Hollberg, Leo W.; McIntosh, Alexander K.; Brown, Elliott R.

    1996-12-01

    The development of low-temperature-grown GaAs photomixers enables the construction of a microwave to submillimeter- wave source capable of large frequency sweeps. By utilizing semiconductor diode lasers to drive the photomixer, this source is all solid-state and compact, and has small power consumption. Frequency stabilization of the semiconductor diode lasers allows this source to be phase-locked to an external microwave reference. Two 805 nm extended-cavity- diode lasers are mixed in a low-temperature-grown GaAs photoconductive photomixer. The difference-frequency mixing product is radiated by a planar spiral antenna and collimated by a Si lens. This output is phase-locked to a microwave reference by downconverting it in a whisker- contacted Schottky-barrier diode harmonic mixer and using the output to offset-phase-lock one laser to the other. The photomixer output power is 300 nW at 200 GHz and 10 nW at 1.6 THz, as measured by a 4 K InSb bolometer calibrated with a methanol laser and a power meter at 526 and 812 GHz.

  12. Rapid Asymmetric Inflation and Early Cosmology in Theories with Sub-Millimeter Dimensions

    CERN Document Server

    Arkani-Hamed, N; Kaloper, Nemanja; March-Russell, John David; Arkani-Hamed, Nima; Dimopoulos, Savas; Kaloper, Nemanja; March-Russell, John

    2000-01-01

    It was recently pointed out that the fundamental Planck mass could be close to the TeV scale with the observed weakness of gravity at long distances being due the existence of new sub-millimeter spatial dimensions. In this picture the standard model fields are localized to a $(3+1)$-dimensional wall or ``3-brane''. We show that in such theories there exist attractive models of inflation that occur while the size of the new dimensions are still small. We show that it is easy to produce the required number of efoldings, and further that the density perturbations $\\delta\\rho/\\rho$ as measured by COBE can be easily reproduced, both in overall magnitude and in their approximately scale-invariant spectrum. In the minimal approach, the inflaton field is just the moduli describing the size of the internal dimensions, the role of the inflationary potential being played by the stabilizing potential of the internal space. We show that under quite general conditions, the inflationary era is followed by an epoch of contra...

  13. A FIRST LOOK AT THE AURIGA-CALIFORNIA GIANT MOLECULAR CLOUD WITH HERSCHEL AND THE CSO: CENSUS OF THE YOUNG STELLAR OBJECTS AND THE DENSE GAS

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, Paul M. [Astronomy Department, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Fallscheer, Cassandra [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2 (Canada); Ginsburg, Adam [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-0389 (United States); Terebey, Susan [Department of Physics and Astronomy PS315, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Andre, Philippe; Koenyves, Vera [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d' Astrophysique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Di Francesco, James; Matthews, Brenda C. [Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Peterson, Dawn E., E-mail: pmh@astro.as.utexas.edu, E-mail: Cassandra.Fallscheer@nrc-cnrc.gc.ca, E-mail: adam.ginsburg@colorado.edu, E-mail: sterebe@calstatela.edu, E-mail: pandre@cea.fr, E-mail: vera.konyves@cea.fr, E-mail: tbourke@cfa.harvard.edu, E-mail: James.DiFrancesco@nrc-cnrc.gc.ca, E-mail: Brenda.Matthews@nrc-cnrc.gc.ca, E-mail: dpeterson@spacescience.org [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80303 (United States)

    2013-02-20

    We have mapped the Auriga/California molecular cloud with the Herschel PACS and SPIRE cameras and the Bolocam 1.1 mm camera on the Caltech Submillimeter Observatory with the eventual goal of quantifying the star formation and cloud structure in this giant molecular cloud (GMC) that is comparable in size and mass to the Orion GMC, but which appears to be forming far fewer stars. We have tabulated 60 compact 70/160 {mu}m sources that are likely pre-main-sequence objects and correlated those with Spitzer and WISE mid-IR sources. At 1.1 mm, we find 18 cold, compact sources and discuss their properties. The most important result from this part of our study is that we find a modest number of additional compact young objects beyond those identified at shorter wavelengths with Spitzer. We also describe the dust column density and temperature structure derived from our photometric maps. The column density peaks at a few Multiplication-Sign 10{sup 22} cm{sup -2} (N {sub H2}) and is distributed in a clear filamentary structure along which nearly all of the pre-main-sequence objects are found. We compare the young stellar object surface density to the gas column density and find a strong nonlinear correlation between them. The dust temperature in the densest parts of the filaments drops to {approx}10 K from values {approx}14-15 K in the low-density parts of the cloud. We also derive the cumulative mass fraction and probability density function of material in the cloud, which we compare with similar data on other star-forming clouds.

  14. Measurement of stratospheric and mesospheric winds with a submillimeter wave limb sounder: results from JEM/SMILES and simulation study for SMILES-2

    Science.gov (United States)

    Baron, Philippe; Manago, Naohiro; Ozeki, Hiroyuki; Irimajiri, Yoshihisa; Murtagh, Donal; Uzawa, Yoshinori; Ochiai, Satoshi; Shiotani, Masato; Suzuki, Makoto

    2015-10-01

    Satellite missions for measuring winds in the troposphere and thermosphere will be launched in a near future. There is no plan to observe winds in the altitude range between 30-90 km, though middle atmospheric winds are recognized as an essential parameter in various atmospheric research areas. Sub-millimetre limb sounders have the capability to fill this altitude gap. In this paper, we summarize the wind retrievals obtained from the Japanese Superconducting Submillimeter Wave Limb Emission Sounder (SMILES) which operated from the International Space Station between September 2009 and April 2010. The results illustrate the potential of such instruments to measure winds. They also show the need of improving the wind representation in the models in the Tropics, and globally in the mesosphere. A wind measurement sensitivity study has been conducted for its successor, SMILES-2, which is being studied in Japan. If it is realized, sub-millimeter and terahertz molecular lines suitable to determine line-of-sight winds will be measured. It is shown that with the current instrument definition, line-of-sight winds can be observed from 20 km up to more than 160 km. Winds can be retrieved with a precision better than 5 ms-1 and a vertical resolution of 2-3 km between 35-90 km. Above 90 km, the precision is better than 10 ms-1 with a vertical resolution of 3-5 km. Measurements can be performed day and night with a similar sensitivity. Requirements on observation parameters such as the antenna size, the satellite altitude are discussed. An alternative setting for the spectral bands is examined. The new setting is compatible with the general scientific objectives of the mission and the instrument design. It allows to improve the wind measurement sensitivity between 35 to 90 km by a factor 2. It is also shown that retrievals can be performed with a vertical resolution of 1 km and a precision of 5-10 ms-1 between 50 and 90 km.

  15. Testing the Formation Mechanism of Sub-Stellar Objects in Lupus (A SOLA Team Study)

    Science.gov (United States)

    De Gregorio-Monsalvo, Itziar; Lopez, C.; Takahashi, S.; Santamaria-Miranda

    2017-06-01

    The international SOLA team (Soul of Lupus with ALMA) has identified a set of pre- and proto-stellar candidates in Lupus 1 and 3 of substellar nature using 1.1mm ASTE/AzTEC maps and our optical to submillimeter database. We have observed with ALMA the most promising pre- and proto-brown dwarfs candidates. Our aims are to provide insights on how substellar objects form and evolve, from the equivalent to the pre-stellar cores to the Class II stage in the low mass regime of star formation. Our sample comprises 33 pre-stellar objects, 7 Class 0 and I objects, and 22 Class II objects.

  16. Laser wavelength metrology with color sensor chips.

    Science.gov (United States)

    Jones, Tyler B; Otterstrom, Nils; Jackson, Jarom; Archibald, James; Durfee, Dallin S

    2015-12-14

    We present a laser wavelength meter based on a commercial color sensor chip. The chip consists of an array of photodiodes with different absorptive color filters. By comparing the relative amplitudes of light on the photodiodes, the wavelength of light can be determined. In addition to absorption in the filters, etalon effects add additional spectral features which improve the precision of the device. Comparing the measurements from the device to a commercial wavelength meter and to an atomic reference, we found that the device has picometer-level precision and picometer-scale drift over a period longer than a month.

  17. Precise absolute gamma-ray wavelength measurements

    Science.gov (United States)

    Kessler, E. G.; Dewey, M. S.; Greene, G. L.; Deslattes, R. D.; Börner, H.

    1991-10-01

    Gamma-ray wavelengths measured with the joint NIST/ILL GAMS4 facility at the High Flux Reactor, Grenoble, France, are discussed. This primary goal of these measurements is gamma-ray wavelengths which are consistent with the optical wavelength scale and the Rydberg constant with an uncertainty no larger than 0.1 ppm for energies up to 5 MeV. The current status of the Bragg angle and crystal lattice spacing measurements on reference energy values, the neutron mass, and the determination of fundamental constants is reviewed. Measurement of structure factors at high energies is also considered.

  18. Selective excavation of decalcified dentin using a mid-infrared tunable nanosecond pulsed laser: wavelength dependency in the 6 μm wavelength range

    Science.gov (United States)

    Ishii, Katsunori; Saiki, Masayuki; Yoshikawa, Kazushi; Yasuo, Kenzo; Yamamoto, Kazuyo; Awazu, Kunio

    2011-07-01

    Selective caries treatment has been anticipated as an essential application of dentistry. In clinic, some lasers have already realized the optical drilling of dental hard tissue. However, conventional lasers lack the selectivity, and still depend on the dentist's ability. Based on the absorption property of carious dentin, 6 μm wavelength range shows specific absorptions and promising characteristics for excavation. The objective of this study is to develop a selective excavation of carious dentin by using the laser ablation with 6 μm wavelength range. A mid-infrared tunable pulsed laser was obtained by difference-frequency generation technique. The wavelength was tuned around the absorption bands called amide 1 and amide 2. In the wavelength range from 5.75 to 6.60 μm, the difference of ablation depth between demineralized and normal dentin was observed. The wavelength at 6.02 μm and the average power density of 15 W/cm2, demineralized dentin was removed selectively with less-invasive effect on normal dentin. The wavelength at 6.42 μm required the increase of average power density, but also showed the possibility of selective ablation. This study provided a valuable insight into a wavelength choice for a novel dental laser device under development for minimal intervention dentistry.

  19. Visible-Wavelength Integrated Spectroscopy of Binary Asteroids

    Science.gov (United States)

    Reiss, A. E.; Marchis, F.; Emery, J. P.

    2009-12-01

    Binary asteroid systems consist of two small planetary bodies orbiting a common center of mass. To date, approximately 65 systems have been imaged using adaptive optics, Hubble Space Telescope observations, and various radar imaging methods. An additional 100 binaries are suspected to exist based on light curve analysis and new discoveries are being announced every month. One important task involved in the study of these systems is the classification of their surface mineralogy. The compositional characterization of asteroid surfaces requires observations across a wide wavelength range. A number of rigorous classification methods have been used to group asteroids into classes based on their observed characteristics. Most recently, a feature-based taxonomy was developed by Bus and Binzel [Bus S. J. and Binzel R. P. (2002) Icarus 158, 146-177]. Bus and Binzel decomposed the visible-wavelength (0.44 - 0.92 μm) spectra of asteroids into three major groups—complexes C-, S-, and X-. Each complex was then further refined into 26 sub-classes associated with distinct mineralogical surface features. Using the Shane 3-meter telescope at Lick Observatory, we observed twelve binary asteroid systems with the KAST double spectrograph. The primary observations were conducted on three nights between May and July of 2009 as a part of an observation program to complete the Virtual Observatory Binary Asteroids Database (VOBAD). The spectrograph at the Shane telescope provides wavelength coverage between 0.3 and 1.0 μm using both blue (0.3-0.57 μm) and red (0.53-1.0 μm) channels, with each spectrograph optimized for its wavelength range. Using this instrument, we obtained a comprehensive measurement of our targets' visible spectra, exceeding the wavelength range over which Bus and Binzel taxonomy is based. We obtained visible-wavelength (0.3 - 1.0 μm) spectra for twelve binary asteroid systems, including six objects not previously classified using Bus and Binzel taxonomic

  20. High efficiency dielectric metasurfaces at visible wavelengths

    CERN Document Server

    Devlin, Robert C; Chen, Wei-Ting; Oh, Jaewon; Capasso, Federico

    2016-01-01

    Metasurfaces are planar optical elements that hold promise for overcoming the limitations of refractive and conventional diffractive optics1-3. Dielectric metasurfaces demonstrated thus far4-10 are limited to transparency windows at infrared wavelengths because of significant optical absorption and loss at visible wavelengths. It is critical that new materials and fabrication techniques be developed for dielectric metasurfaces at visible wavelengths to enable applications such as three-dimensional displays, wearable optics and planar optical systems11. Here, we demonstrate high performance titanium dioxide dielectric metasurfaces in the form of holograms for red, green and blue wavelengths with record absolute efficiency (>78%). We use atomic layer deposition of amorphous titanium dioxide that exhibits low surface roughness of 0.738 nm and ideal optical properties. To fabricate the metasurfaces we use a lift-off-like process that allows us to produce highly anisotropic nanofins with shape birefringence. This ...

  1. Wavelength-versatile optical vortex lasers

    Science.gov (United States)

    Omatsu, Takashige; Miyamoto, Katsuhiko; Lee, Andrew J.

    2017-12-01

    The unique properties of optical vortex beams, in particular their spiral wavefront, have resulted in the emergence of a wide range of unique applications for this type of laser output. These applications include optical tweezing, free space optical communications, microfabrication, environmental optics, and astrophysics. However, much like the laser in its infancy, the adaptation of this type of laser output requires a diversity of wavelengths. We report on recent progress on development of optical vortex laser sources and in particular, focus on their wavelength extension, where nonlinear optical processes have been used to generate vortex laser beams with wavelengths which span the ultraviolet to infrared. We show that nonlinear optical conversion can be used to not only diversify the output wavelength of these sources, but can be used to uniquely engineer the wavefront and spatial properties of the laser output.

  2. Wavelength Conversion by using Multiple Fibres

    DEFF Research Database (Denmark)

    Fenger, Christian; Iversen, Villy Bæk

    2002-01-01

    We explain how wavelength conversion can be achieved by using multiple fibres, and show that multiple fibres reduce blocking probability in dynamic all-optical networks, whereby the need for conversion in all-optical networks will be limited......We explain how wavelength conversion can be achieved by using multiple fibres, and show that multiple fibres reduce blocking probability in dynamic all-optical networks, whereby the need for conversion in all-optical networks will be limited...

  3. SHARC II: A Caltech Submillimeter Observatory Facility Camera with 384 Pixels

    Science.gov (United States)

    Dowell, C. Darren; Allen, Christine A.; Babu, Sachidananda; Freund, Minoru; Gardner, Matthew B.; Groseth, Jeffrey; Jhabvala, Murzy; Kovacs, Attila; Lis, Dariusz C.; Moseley, S. Harvey, Jr.

    2002-01-01

    SHARC II is a background-limited 350 micron and 450 micron facility camera for the Caltech Submillimeter Observatory undergoing commissioning in 2002. The key component of SHARC II is a 12 x 32 array of doped silicon 'pop-up' bolometers developed at NASA/Goddard. Each 1 mm x 1 mm pixel is coated with a 400 Omega/square bismuth film and located lambda/4 above a reflective backshort to achieve greater than 75% absorption efficiency. The pixels cover the focal plane with greater than 90% filling factor. At 350 microns, the SHARC II pixels are separated by 0.65 lambda/D. In contrast to the silicon bolometers in the predecessor of SHARC II, each doped thermistor occupies nearly the full area of the pixel, which lowers the 1/f knee of tile detector noise to less than 0.03 Hz, under load, at tile bath temperature of 0.36 K. The bolometers are AC-biased and read in 'total power' mode to take advantage of the improved stability. Each bolometer is biased through a custom approx. 130 MOmega CrSi load resistor at 7 K and read with a commercial JFET at 120 K. The JFETs and load resistors are integrated with the detectors into a single assembly to minimize microphonic noise. Electrical connection across the 0.36 K to 4 K and 4 K to 120 K temperature interfaces is accomplished with lithographed metal wires on dielectric substrates. In the best 25% of winter nights on Mauna Kea, SHARC II is expected to have an NEFD at 350 micron of 1 Jy Hz(sup -1/2) or better. The new camera should be at least 4 times faster at detecting known point sources and 30 times faster at mapping large areas compared to the prior instrument.

  4. An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South: Spectroscopic Redshifts

    Science.gov (United States)

    Danielson, A. L. R.; Swinbank, A. M.; Smail, Ian; Simpson, J. M.; Casey, C. M.; Chapman, S. C.; da Cunha, E.; Hodge, J. A.; Walter, F.; Wardlow, J. L.; Alexander, D. M.; Brandt, W. N.; de Breuck, C.; Coppin, K. E. K.; Dannerbauer, H.; Dickinson, M.; Edge, A. C.; Gawiser, E.; Ivison, R. J.; Karim, A.; Kovacs, A.; Lutz, D.; Menten, K.; Schinnerer, E.; Weiß, A.; van der Werf, P.

    2017-05-01

    We present spectroscopic redshifts of {\\text{}}{S}870μ {{m}} ≳ 2 mJy submillimeter galaxies (SMGs), which have been identified from the ALMA follow-up observations of 870 μm detected sources in the Extended Chandra Deep Field South (the ALMA-LESS survey). We derive spectroscopic redshifts for 52 SMGs, with a median of z = 2.4 ± 0.1. However, the distribution features a high-redshift tail, with ˜23% of the SMGs at z≥slant 3. Spectral diagnostics suggest that the SMGs are young starbursts, and the velocity offsets between the nebular emission and UV ISM absorption lines suggest that many are driving winds, with velocity offsets of up to 2000 km s-1. Using the spectroscopic redshifts and the extensive UV-to-radio photometry in this field, we produce optimized spectral energy distributions (SEDs) using Magphys, and use the SEDs to infer a median stellar mass of {M}\\star = (6 ± 1)× 1010 M {}⊙ for our SMGs with spectroscopic redshift. By combining these stellar masses with the star formation rates (measured from the far-infrared SEDs), we show that SMGs (on average) lie a factor of ˜5 above the so-called “main sequence” at z˜ 2. We provide this library of 52 template fits with robust and uniquely well-sampled SEDs as a resource for future studies of SMGs, and also release the spectroscopic catalog of ˜2000 (mostly infrared-selected) galaxies targeted as part of the spectroscopic campaign.

  5. A retrieval algorithm of hydrometer profile for submillimeter-wave radiometer

    Science.gov (United States)

    Liu, Yuli; Buehler, Stefan; Liu, Heguang

    2017-04-01

    Vertical profiles of particle microphysics perform vital functions for the estimation of climatic feedback. This paper proposes a new algorithm to retrieve the profile of the parameters of the hydrometeor(i.e., ice, snow, rain, liquid cloud, graupel) based on passive submillimeter-wave measurements. These parameters include water content and particle size. The first part of the algorithm builds the database and retrieves the integrated quantities. Database is built up by Atmospheric Radiative Transfer Simulator(ARTS), which uses atmosphere data to simulate the corresponding brightness temperature. Neural network, trained by the precalculated database, is developed to retrieve the water path for each type of particles. The second part of the algorithm analyses the statistical relationship between water path and vertical parameters profiles. Based on the strong dependence existing between vertical layers in the profiles, Principal Component Analysis(PCA) technique is applied. The third part of the algorithm uses the forward model explicitly to retrieve the hydrometeor profiles. Cost function is calculated in each iteration, and Differential Evolution(DE) algorithm is used to adjust the parameter values during the evolutionary process. The performance of this algorithm is planning to be verified for both simulation database and measurement data, by retrieving profiles in comparison with the initial one. Results show that this algorithm has the ability to retrieve the hydrometeor profiles efficiently. The combination of ARTS and optimization algorithm can get much better results than the commonly used database approach. Meanwhile, the concept that ARTS can be used explicitly in the retrieval process shows great potential in providing solution to other retrieval problems.

  6. A submillimeter galaxy illuminating its circumgalactic medium: Lyα scattering in a cold, clumpy outflow

    Energy Technology Data Exchange (ETDEWEB)

    Geach, J. E.; Coppin, K. E. K.; Smith, D. J. B. [Center for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Bower, R. G.; Alexander, D. M.; Swinbank, A. M. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Bremer, M. N. [School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapin, E. L. [XMM SOC, ESAC, Apartado 78, E-28691 Villanueva de la Canada, Madrid (Spain); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University Halifax, NS B3H 3J5 (Canada); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Dunlop, J. S.; Koprowski, M. P.; Michałowski, M. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Farrah, D. [Virginia Polytechnic Institute and State University Department of Physics, MC 0435, 910 Drillfield Drive, Blacksburg, VA 24061 (United States); Jenness, T. [Joint Astronomy Centre, 660 North A' ohoku Place University Park, Hilo, HI 96720 (United States); Robson, E. I. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Scott, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Spaans, M. [Kapteyn Institute, University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands); Van der Werf, P., E-mail: j.geach@herts.ac.uk [Leiden Observatory, Leiden University, PO box 9513, 2300 RA Leiden (Netherlands)

    2014-09-20

    We report the detection at 850 μm of the central source in SSA22-LAB1, the archetypal 'Lyman-α Blob' (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S {sub 850} = 4.6 ± 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L {sub IR} ≈ 10{sup 12} L {sub ☉}. The position of an active source at the center of a ∼50 kpc radius ring of linearly polarized Lyα emission detected by Hayes et al. suggests that the central source is leaking Lyα photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Lyα morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Lyα line profiles of the two 'lobes' are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Lyα emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Lyα: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?.

  7. Improved wedge method for the measurement of sub-millimeter slice thicknesses in magnetic resonance imaging.

    Science.gov (United States)

    Kanazawa, Tsutomu; Ohkubo, Masaki; Kondo, Tatsuya; Miyazawa, Takayuki; Inagawa, Shoichi

    2017-12-01

    The standard method for measuring the slice thickness of magnetic resonance images uses the inclined surface of a wedge (wedge method); it is sensitive to small increases in noise because of the differentiation of the edge response function (ERF) required. The purpose of this study was to improve the wedge method by fitting a curve to the ERF. The curve-fit function was obtained by convolving an ideal ERF (a ramp function) with a Gaussian function to represent ERF blurring. Measurements of 5- and 3-mm slice thicknesses were performed on a 3T scanner using the conventional wedge method, the improved wedge method, and another standard method using an inclined slab (slab method). Subsequently, 0.5- and 0.25-mm slice thicknesses from multiple slices acquired using a three-dimensional sequence were measured using the improved wedge method. When measuring 5-mm slices, the differences in measurements obtained using the improved wedge method and the conventional slab and wedge methods were very small: <0.6% of the 5-mm slice thickness. The difference was ≤1.7% for 3-mm slices. For 0.5- and 0.25-mm slices, the mean values obtained using the improved wedge method were 0.543 ± 0.007 mm and 0.247 ± 0.015 mm, with a 1.2 and 5.9% coefficient of variation across slices, respectively. The improved wedge method is valid and potentially applicable to the measurement of sub-millimeter slice thicknesses.

  8. A sub-millimeter resolution detector module for small-animal PET applications

    Science.gov (United States)

    Sacco, I.; Dohle, R.; Fischer, P.; Gola, A.; Piemonte, C.; Ritzert, M.

    2017-01-01

    We present a gamma detection module optimized for very high resolution PET applications, able to resolve arrays of scintillating crystals with sub-millimeter pitch. The detector is composed of a single ceramic substrate (LTCC): it hosts four flip-chip mounted PETA5 ASICs on the bottom side and an array of SiPM sensors on the top surface, fabricated in HD-RGB technology by FBK. Each chip has 36 channels, for a maximum of 144 readout channels on a sensitive area of about 32 mm × 32 mm. The module is MR-compatible. The thermal decoupling of the readout electronics from the photon sensors is obtained with an efficient internal liquid channel, integrated within the ceramic substrate. Two modules have been designed, based on different SiPM topologies: • Light spreader-based: an array of 12 × 12 SiPMs, with an overall pitch of 2.5 mm, is coupled with a scintillators array using a 1 mm thick glass plate. The light from one crystal is spread over a group of SiPMs, which are read out in parallel using PETA5 internal neighbor logic. • Interpolating SiPM-based: ISiPMs are intrinsic position-sensitive sensors. The photon diodes in the array are connected to one of the four available outputs so that the center of gravity of any bunch of detected photons can be reconstructed using a proper weight function of the read out amplitudes. An array of ISiPMs, each 7.5 mm× 5 mm sized, is directly coupled with the scintillating crystals. Both modules can clearly resolve LYSO arrays with a pitch of only 0.833 mm. The detector can be adjusted for clinical PET, where it has already shown ToF resolution of about 230 ps CRT at FWHM. The module designs, their features and results are described.

  9. Wavelength mismatch effect in electromagnetically induced absorption

    Energy Technology Data Exchange (ETDEWEB)

    Bharti, Vineet [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Wasan, Ajay [Department of Physics, Indian Institute of Technology, Roorkee 247667 (India); Natarajan, Vasant [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

    2016-07-15

    We present a theoretical investigation of the phenomenon of electromagnetically induced absorption (EIA) in a 4-level system consisting of vee and ladder subsystems. The four levels are coupled using one weak probe field, and two strong control fields. We consider an experimental realization using energy levels of Rb. This necessitates dealing with different conditions of wavelength mismatch—near-perfect match where all three wavelengths are approximately equal; partial mismatch where the wavelength of one control field is less than the other fields; and complete mismatch where all three wavelengths are unequal. We present probe absorption profiles with Doppler averaging at room temperature to account for experiments in a room temperature Rb vapor cell. Our analysis shows that EIA resonances can be studied using Rydberg states excited with diode lasers. - Highlights: • Wavelength mismatch effect is investigated in electromagnetically induced absorption (EIA). • An experimental realization of 4-level vee + ladder system using energy levels of rubidium atom is presented. • EIA resonances are studied under different conditions of wavelength mismatch. • Possibility of observation of EIA using Rydberg states excited with diode lasers.

  10. Objective thermomechanics

    CERN Document Server

    Fülöp, Tamás

    2015-01-01

    An irreversible thermodynamical theory of solids is presented where the kinematic quantities are defined in an automatically objective way. Namely, auxiliary elements like reference frame, reference time and reference configuration are avoided by formulating the motion of the continuum on spacetime directly, utilizing the Weyl-Matolcsi description of spacetime. This restricts the range of definable kinematic quantities heavily. Solids are distinguished from fluids by possessing not only an instantaneous metric tensor but a relaxed metric, too, that represents the natural geometric structure of the solid. The comparison of the instantaneous metric to the relaxed one is the basis of the definition of the elastic state variable, the elastic deformedness tensor. Thermal expansion is conceived as the temperature dependence of the relaxed metric. As opposed to this reversible type of change, plasticity means an irreversible change in the relaxed metric, and is describable via a plastic change rate tensor. The relat...

  11. A 12 GHz wavelength spacing multi-wavelength laser source for wireless communication systems

    Science.gov (United States)

    Peng, P. C.; Shiu, R. K.; Bitew, M. A.; Chang, T. L.; Lai, C. H.; Junior, J. I.

    2017-08-01

    This paper presents a multi-wavelength laser source with 12 GHz wavelength spacing based on a single distributed feedback laser. A light wave generated from the distributed feedback laser is fed into a frequency shifter loop consisting of 50:50 coupler, dual-parallel Mach-Zehnder modulator, optical amplifier, optical filter, and polarization controller. The frequency of the input wavelength is shifted and then re-injected into the frequency shifter loop. By re-injecting the shifted wavelengths multiple times, we have generated 84 optical carriers with 12 GHz wavelength spacing and stable output power. For each channel, two wavelengths are modulated by a wireless data using the phase modulator and transmitted through a 25 km single mode fiber. In contrast to previously developed schemes, the proposed laser source does not incur DC bias drift problem. Moreover, it is a good candidate for radio-over-fiber systems to support multiple users using a single distributed feedback laser.

  12. Sparsity-based single-shot sub-wavelength coherent diffractive imaging

    CERN Document Server

    Szameit, A; Osherovich, E; Bullkich, E; Sidorenko, P; Dana, H; Steiner, S; Kley, E B; Gazit, S; Cohen-Hyams, T; Shoham, S; Zibulevsky, M; Yavneh, I; Eldar, Y C; Cohen, O; Segev, M

    2011-01-01

    We present the experimental reconstruction of sub-wavelength features from the far-field intensity of sparse optical objects: sparsity-based sub-wavelength imaging combined with phase-retrieval. As examples, we demonstrate the recovery of random and ordered arrangements of 100 nm features with the resolution of 30 nm, with an illuminating wavelength of 532 nm. Our algorithmic technique relies on minimizing the number of degrees of freedom; it works in real-time, requires no scanning, and can be implemented in all existing microscopes - optical and non-optical.

  13. The cryomechanical design of MUSIC: a novel imaging instrument for millimeter-wave astrophysics at the Caltech Submillimeter Observatory

    Science.gov (United States)

    Hollister, Matthew I.; Czakon, Nicole G.; Day, Peter K.; Downes, Thomas P.; Duan, Ran; Gao, Jiansong; Glenn, Jason; Golwala, Sunil R.; LeDuc, Henry G.; Maloney, Philip R.; Mazin, Benjamin A.; Nguyen, Hien Trong; Noroozian, Omid; Sayers, Jack; Schlaerth, James; Siegel, Seth; Vaillancourt, John E.; Vayonakis, Anastasios; Wilson, Philip; Zmuidzinas, Jonas

    2010-07-01

    MUSIC (Multicolor Submillimeter kinetic Inductance Camera) is a new facility instrument for the Caltech Submillimeter Observatory (Mauna Kea, Hawaii) developed as a collaborative effect of Caltech, JPL, the University of Colorado at Boulder and UC Santa Barbara, and is due for initial commissioning in early 2011. MUSIC utilizes a new class of superconducting photon detectors known as microwave kinetic inductance detectors (MKIDs), an emergent technology that offers considerable advantages over current types of detectors for submillimeter and millimeter direct detection. MUSIC will operate a focal plane of 576 spatial pixels, where each pixel is a slot line antenna coupled to multiple detectors through on-chip, lumped-element filters, allowing simultaneously imaging in four bands at 0.86, 1.02, 1.33 and 2.00 mm. The MUSIC instrument is designed for closed-cycle operation, combining a pulse tube cooler with a two-stage Helium-3 adsorption refrigerator, providing a focal plane temperature of 0.25 K with intermediate temperature stages at approximately 50, 4 and 0.4 K for buffering heat loads and heat sinking of optical filters. Detector readout is achieved using semi-rigid coaxial cables from room temperature to the focal plane, with cryogenic HEMT amplifiers operating at 4 K. Several hundred detectors may be multiplexed in frequency space through one signal line and amplifier. This paper discusses the design of the instrument cryogenic hardware, including a number of features unique to the implementation of superconducting detectors. Predicted performance data for the instrument system will also be presented and discussed.

  14. Constrain the SED Type of Unidentified Fermi Objects

    Directory of Open Access Journals (Sweden)

    An-Li Tsai

    2013-09-01

    Full Text Available 2FGL J1823.8+4312 and 2FGL J1304.1-2415 are two unidentified Fermi objects which are associated with cluster of galaxies. In order to exam the possibility of cluster of galaxies as gamma-ray emitters, we search for counterpart of these two unidentified Fermi objects in other wavebands. However, we find other candidate to be more likely the counterpart of the unidentified Fermi object for both sources. We compare their light curves and SEDs in order to identify their source types. However, data at millimeter and sub-millimeter wavebands, which is important for us to constrain the SED at synchrotron peak, is lacking of measurement. Therefore, we proposed to SMA observation for these two sources. We have got data and are doing further analysis.

  15. Dual-wavelengths photoacoustic temperature measurement

    Science.gov (United States)

    Liao, Yu; Jian, Xiaohua; Dong, Fenglin; Cui, Yaoyao

    2017-02-01

    Thermal therapy is an approach applied in cancer treatment by heating local tissue to kill the tumor cells, which requires a high sensitivity of temperature monitoring during therapy. Current clinical methods like fMRI near infrared or ultrasound for temperature measurement still have limitations on penetration depth or sensitivity. Photoacoustic temperature sensing is a newly developed temperature sensing method that has a potential to be applied in thermal therapy, which usually employs a single wavelength laser for signal generating and temperature detecting. Because of the system disturbances including laser intensity, ambient temperature and complexity of target, the accidental errors of measurement is unavoidable. For solving these problems, we proposed a new method of photoacoustic temperature sensing by using two wavelengths to reduce random error and increase the measurement accuracy in this paper. Firstly a brief theoretical analysis was deduced. Then in the experiment, a temperature measurement resolution of about 1° in the range of 23-48° in ex vivo pig blood was achieved, and an obvious decrease of absolute error was observed with averagely 1.7° in single wavelength pattern while nearly 1° in dual-wavelengths pattern. The obtained results indicates that dual-wavelengths photoacoustic sensing of temperature is able to reduce random error and improve accuracy of measuring, which could be a more efficient method for photoacoustic temperature sensing in thermal therapy of tumor.

  16. THE TWO-WAVELENGTH METHOD OF MICROSPECTROPHOTOMETRY

    Science.gov (United States)

    Mendelsohn, Mortimer L.

    1961-01-01

    In connection with the potential development of automatic two-wavelength microspectrophotometry, a new version of the two-wavelength method has been formulated. Unlike its predecessors, the Ornstein and Patau versions, the new method varies the area of the photometric field seeking to maximize a relationship between distributional errors at the two wavelengths. Stating this distributional error relationship in conventional photometric terms, the conditions at the maximum are defined by taking the first derivative with respect to field size and setting it equal to zero. This operation supplies two equations; one relates the transmittances at the two wavelengths, and a second states the relative amount of chromophore in the field in terms of transmittance at one wavelength. With the first equation to drive a servomechanism which sets the appropriate field size, the desired answer can then be obtained directly and continuously from the second equation. The result is identical in theory with those of the earlier methods, but the technique is more suitable for electronic computing. PMID:14472536

  17. A Literature Review of Millimeter and Submillimeter Radiation Absorption and Scattering in the Atmosphere

    Science.gov (United States)

    1978-10-01

    Best’s drop-size distribution. His results are shown in Table XXVIII. Serge Godard measured the reflectivity of rain drops as a function of drop... Serge L. Godard, "Propagation of Cm and MM Wavelengths Through Precipitation." IEEE Transactions on Antennaes and Propagation, Vol. AP-18. No. 4, pp...Dr. E.E. Altshuler; OPA, Dr. R. Fenn, Research Library L.G. Hanscom Field Bedford, MA 01730 .,...,.^ ■^-"" "~- AFTAC/TFR, CPT J. Lange

  18. The ArTéMiS wide-field sub-millimeter camera: preliminary on-sky performance at 350 microns

    Science.gov (United States)

    Revéret, Vincent; André, Philippe; Le Pennec, Jean; Talvard, Michel; Agnèse, Patrick; Arnaud, Agnès.; Clerc, Laurent; de Breuck, Carlos; Cigna, Jean-Charles; Delisle, Cyrille; Doumayrou, Eric; Duband, Lionel; Dubreuil, Didier; Dumaye, Luc; Ercolani, Eric; Gallais, Pascal; Groult, Elodie; Jourdan, Thierry; Leriche, Bernadette; Maffei, Bruno; Lortholary, Michel; Martignac, Jérôme; Rabaud, Wilfried; Relland, Johan; Rodriguez, Louis; Vandeneynde, Aurélie; Visticot, François

    2014-07-01

    ArTeMiS is a wide-field submillimeter camera operating at three wavelengths simultaneously (200, 350 and 450 μm). A preliminary version of the instrument equipped with the 350 μm focal plane, has been successfully installed and tested on APEX telescope in Chile during the 2013 and 2014 austral winters. This instrument is developed by CEA (Saclay and Grenoble, France), IAS (France) and University of Manchester (UK) in collaboration with ESO. We introduce the mechanical and optical design, as well as the cryogenics and electronics of the ArTéMiS camera. ArTeMiS detectors consist in Si:P:B bolometers arranged in 16×18 sub-arrays operating at 300 mK. These detectors are similar to the ones developed for the Herschel PACS photometer but they are adapted to the high optical load encountered at APEX site. Ultimately, ArTeMiS will contain 4 sub-arrays at 200 μm and 2×8 sub-arrays at 350 and 450 μm. We show preliminary lab measurements like the responsivity of the instrument to hot and cold loads illumination and NEP calculation. Details on the on-sky commissioning runs made in 2013 and 2014 at APEX are shown. We used planets (Mars, Saturn, Uranus) to determine the flat-field and to get the flux calibration. A pointing model was established in the first days of the runs. The average relative pointing accuracy is 3 arcsec. The beam at 350 μm has been estimated to be 8.5 arcsec, which is in good agreement with the beam of the 12 m APEX dish. Several observing modes have been tested, like "On- The-Fly" for beam-maps or large maps, spirals or raster of spirals for compact sources. With this preliminary version of ArTeMiS, we concluded that the mapping speed is already more than 5 times better than the previous 350 μm instrument at APEX. The median NEFD at 350 μm is 600 mJy.s1/2, with best values at 300 mJy.s1/2. The complete instrument with 5760 pixels and optimized settings will be installed during the first half of 2015.

  19. High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Pei-Hsin; Chung, Hsiao-Wen [Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, Ping-Huei [Imaging Research Center, Taipei Medical University, Taipei 11031, Taiwan and Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan (China); Wu, Ming-Long, E-mail: minglong.wu@csie.ncku.edu.tw [Institute of Medical Informatics, National Cheng-Kung University, Tainan 70101, Taiwan and Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan 70101, Taiwan (China); Chuang, Tzu-Chao [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Shih, Yi-Yu [Siemens Limited Healthcare Sector, Taipei 11503, Taiwan (China); Huang, Teng-Yi [Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2013-12-15

    Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

  20. Kilovoltage beam Monte Carlo dose calculations in submillimeter voxels for small animal radiotherapy.

    Science.gov (United States)

    Bazalova, Magdalena; Zhou, Hu; Keall, Paul J; Graves, Edward E

    2009-11-01

    Small animal conformal radiotherapy (RT) is essential for preclinical cancer research studies and therefore various microRT systems have been recently designed. The aim of this paper is to efficiently calculate the dose delivered using our microRT system based on a microCT scanner with the Monte Carlo (MC) method and to compare the MC calculations to film measurements. Doses from 2-30 mm diameter 120 kVp photon beams deposited in a solid water phantom with 0.2 x 0.2 x 0.2 mm3 voxels are calculated using the latest versions of the EGSnrc codes BEAMNRC and DOSXYZNRC. Two dose calculation approaches are studied: a two-step approach using phase-space files and direct dose calculation with BEAMNRC simulation sources. Due to the small beam size and submillimeter voxel size resulting in long calculation times, variance reduction techniques are studied. The optimum bremsstrahlung splitting number (NBRSPL in BEAMNRC) and the optimum DOSXYZNRC photon splitting (Nsplit) number are examined for both calculation approaches and various beam sizes. The dose calculation efficiencies and the required number of histories to achieve 1% statistical uncertainty--with no particle recycling--are evaluated for 2-30 mm beams. As a final step, film dose measurements are compared to MC calculated dose distributions. The optimum NBRSPL is approximately 1 x 10(6) for both dose calculation approaches. For the dose calculations with phase-space files, Nsplit varies only slightly for 2-30 mm beams and is established to be 300. Nsplit for the DOSXYZNRC calculation with the BEAMNRC source ranges from 300 for the 30 mm beam to 4000 for the 2 mm beam. The calculation time significantly increases for small beam sizes when the BEAMNRC simulation source is used compared to the simulations with phase-space files. For the 2 and 30 mm beams, the dose calculations with phase-space files are more efficient than the dose calculations with BEAMNRC sources by factors of 54 and 1.6, respectively. The dose

  1. A sub-millimeter resolution PET detector module using a multi-pixel photon counter array

    Science.gov (United States)

    Song, Tae Yong; Wu, Heyu; Komarov, Sergey; Siegel, Stefan B.; Tai, Yuan-Chuan

    2010-05-01

    A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 × 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor network. The LSO array consists of 100 crystals, each measuring 0.8 × 0.8 × 3 mm3 and arranged in 0.86 mm pitches. A Monte Carlo simulation was used to aid the design and fabrication of a custom light guide to control distribution of scintillation light over the surface of the MPPC array. The output signals of the nine MPPC are multiplexed by a charge division resistor network to generate four position-encoded analog outputs. Flood image, energy resolution and timing resolution measurements were performed using standard NIM electronics. The linearity of the detector response was investigated using gamma-ray sources of different energies. The 10 × 10 array of 0.8 mm LSO crystals was clearly resolved in the flood image. The average energy resolution and standard deviation were 20.0% full-width at half-maximum (FWHM) and ±5.0%, respectively, at 511 keV. The timing resolution of a single MPPC coupled to a LSO crystal was found to be 857 ps FWHM, and the value for the central region of detector module was 1182 ps FWHM when ±10% energy window was applied. The nonlinear response of a single MPPC when used to read out a single LSO was observed among the corner crystals of the proposed detector module. However, the central region of the detector module exhibits significantly less nonlinearity (6.5% for 511 keV). These results demonstrate that (1) a charge-sharing resistor network can effectively multiplex MPPC signals and reduce the number of output signals without significantly degrading the performance of a PET detector and (2) a custom light guide to permit light sharing

  2. The Interstellar Medium in High-redshift Submillimeter Galaxies as Probed by Infrared Spectroscopy*

    Science.gov (United States)

    Wardlow, Julie L.; Cooray, Asantha; Osage, Willow; Bourne, Nathan; Clements, David; Dannerbauer, Helmut; Dunne, Loretta; Dye, Simon; Eales, Steve; Farrah, Duncan; Furlanetto, Cristina; Ibar, Edo; Ivison, Rob; Maddox, Steve; Michałowski, Michał M.; Riechers, Dominik; Rigopoulou, Dimitra; Scott, Douglas; Smith, Matthew W. L.; Wang, Lingyu; van der Werf, Paul; Valiante, Elisabetta; Valtchanov, Ivan; Verma, Aprajita

    2017-03-01

    Submillimeter galaxies (SMGs) at z≳ 1 are luminous in the far-infrared, and have star formation rates, SFR, of hundreds to thousands of solar masses per year. However, it is unclear whether they are true analogs of local ULIRGs or whether the mode of their star formation is more similar to that in local disk galaxies. We target these questions by using Herschel-PACS to examine the conditions in the interstellar medium (ISM) in far-infrared luminous SMGs at z˜ 1-4. We present 70-160 μm photometry and spectroscopy of the [O IV]26 μm, [Fe II]26 μm, [S III]33 μm, [Si II]34 μm, [O III]52 μm, [N III]57 μm, and [O I]63 μm fine-structure lines and the S(0) and S(1) hydrogen rotational lines in 13 lensed SMGs identified by their brightness in early Herschel data. Most of the 13 targets are not individually spectroscopically detected; we instead focus on stacking these spectra with observations of an additional 32 SMGs from the Herschel archive—representing a complete compilation of PACS spectroscopy of SMGs. We detect [O I]63 μm, [Si II]34 μm, and [N III]57 μm at ≥slant 3σ in the stacked spectra, determining that the average strengths of these lines relative to the far-IR continuum are (0.36+/- 0.12)× {10}-3, (0.84+/- 0.17)× {10}-3, and (0.27+/- 0.10)× {10}-3, respectively. Using the [O III]52 μm/[N III]57 μm emission line ratio, we show that SMGs have average gas-phase metallicities ≳ {Z}⊙ . By using PDR modeling and combining the new spectral measurements with integrated far-infrared fluxes and existing [C II]158 μm data, we show that SMGs have average gas densities, n, of ˜ {10}1-3 {{cm}}-3 and FUV field strengths, {G}0˜ {10}2.2-4.5 (in Habing units: 1.6× {10}-3 {erg} {{cm}}-2 {{{s}}}-1), consistent with both local ULIRGs and lower luminosity star-forming galaxies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia, and important participation from NASA.

  3. Mapping the thermal structure and minor species of Venus mesosphere with ALMA submillimeter observations

    Science.gov (United States)

    Piccialli, A.; Moreno, R.; Encrenaz, T.; Fouchet, T.; Lellouch, E.; Widemann, T.

    2017-10-01

    Context. Water vapor and sulfur compounds are key species in the photochemistry of Venus mesosphere. These species, together with mesospheric temperatures, exhibit drastic temporal variations, both on short timescales (diurnal and day-to-day) as well on long timescales, far from being understood. Aims: We targeted CO, SO, HDO and SO2 transitions in the submillimeter range using the Atacama Large Millimeter Array (ALMA) to study their spatial and temporal variations. Methods: Four sets of observations were acquired on different dates in November 2011 during the first ALMA Early Science observation Cycle 0. Venus angular diameter was about 11'' with an illumination factor of 92%, so that mostly the day side of the planet was mapped. Assuming a nominal CO abundance profile, we retrieved vertical temperature profiles over the entire disk as a function of latitude and local time. Temperature profiles were later used to retrieve SO, SO2, and H2O. We used HDO as a tracer for water assuming a D/H enrichment of 200 times the terrestrial value. Results: We derived 3D maps of mesospheric temperatures in the altitude range 70-105 km. SO, SO2, and H2O are characterized by a negligible abundance below 85 km followed by an increase with altitude in the upper mesosphere. Disk-averaged SO abundances present a maximum mixing ratio of 15.0 ± 3.1 ppb on November 26 followed the next day by a minimum value of 9.9 ± 1.2 ppb. Due to a very low S/N, SO2 could only be derived from the disk-averaged spectrum on the first day of observation revealing an abundance of 16.5 ± 4.6 ppb. We found a SO2/SO ratio of 1.5 ± 0.4. Global maps of SO reveal strong variations both with latitude and local time and from day to day with abundance ranging from < 1 to 15 ppb. H2O disk-averages retrievals reveal a steady decrease from November 14 to 27, with the abundance varying from 3.6 ± 0.6 ppm on the first day to 2.9 ± 0.7 ppm on the last day. H2O maps reveal a slightly higher abundance on the evening

  4. Metallic Colloid Wavelength-Ratiometric Scattering Sensors

    Science.gov (United States)

    Roll, David; Malicka, Joanna; Gryczynski, Ignacy; Gryczynski, Zygmunt

    2009-01-01

    Gold and silver colloids display strong colors as a result of electron oscillations induced by incident light, which are referred to as the plasmon absorption. This absorption is dependent on colloid–colloid proximity, which has been the basis of absorption assays using colloids. We now describe a new approach to optical sensing using the light scattering properties of colloids. Colloid aggregation was induced by avidin–biotin interactions, which shifted the plasmon absorption to longer wavelengths. We found the spectral shift results in changes in the scattering at different incident wavelengths. By measuring the ratio of scattered intensities at two incident wavelengths, this measurement was made independent of the total colloid concentration. The high scattering efficiency of the colloids resulted in intensities equivalent to fluorescence when normalized by the optical density of the fluorophore and colloid. This approach can be used in a wide variety of assay formats, including those commonly used with fluorescence detection. PMID:14570195

  5. Phase extraction for dual-wavelength phase-shift Fizeau interferometry in the presence of multi-beam interference

    Science.gov (United States)

    Cheng, Jinlong; Yuan, Qun; Dou, Yimeng; Yao, Yanxia; Huang, Jialing; Zuo, Chao; Gao, Zhishan

    2017-11-01

    Dual-wavelength interferometry could extend the measured range of single-wavelength interferometry by combining the two single wavelength phases, particularly for the measurement of step height. When testing the high-reflectivity surfaces with the single wavelength Fizeau interferometer, we have presented the π / 4 phase-shift carrier squeezing interferometry (QCSI) method for phase extraction with multi-beam interference (Appl. Opt. 55, 1920-1928, 2016). In this paper, we propose an integer and decimal portions synthetization (IDS) method for the multi-beam interference in the dual-wavelength Fizeau interferometer. One of the single wavelength wrapped phases is demodulated by the multi-beam interference QCSI algorithm, while the second of the single wavelength wrapped phases is extracted by the conventional two-beam interference phase-shift algorithm, so the equivalent wavelength unwrapped phase is derived from the two single wavelength wrapped phase. The decimal portion of synthesized phase is then obtained directly from the first single wavelength wrapped phase, and the integer portion of synthesized phase is obtained from the fringe order of the first single wavelength wrapped phase determined by the equivalent wavelength unwrapped phase. The proposed non-iterative IDS method avoids the common error magnification effect in the two-wavelength techniques, and only requires no more than 8 frame phase-shift interferograms for each single wavelength. Its robust performance is validated by both simulations and experiments in the presence of multi-beam interference as well as phase-shift error for measuring objects with height discontinuities.

  6. Wavelength division multiplexing a practical engineering guide

    CERN Document Server

    Grobe, Klaus

    2013-01-01

    In this book, Optical Wavelength Division Multiplexing (WDM) is approached from a strictly practical and application-oriented point of view. Based on the characteristics and constraints of modern fiber-optic components, transport systems and fibers, the text provides relevant rules of thumb and practical hints for technology selection, WDM system and link dimensioning, and also for network-related aspects such as wavelength assignment and resilience mechanisms. Actual 10/40 Gb/s WDM systems are considered, and a preview of the upcoming 100 Gb/s systems and technologies for even higher bit rate

  7. Variable wavelength selection devices: Physics and applications

    Science.gov (United States)

    Xianyu, Haiqing

    Variable wavelength selection (VWS) achieved by implementing tunability to wavelength discriminating devices has generated great interest in basic science, applied physics, and technology. This thesis focuses on the underlying physics and application of several novel wavelength discriminating devices. Holographical polymer dispersed liquid crystals (HPDLCs) are switchable volume gratings formed by exposing a photopolymerizable monomer and liquid crystal mixture to interfering monochromatic light beams. An HPDLCs wavelength discriminating ability along with its switchability, allow it to be utilized in VWS devices. A novel mode HPDLC, total internal reflection (TIR) HPDLC, has been developed as a wavelength selective filter. The grating planes in this device are tilted so that the diffracted light experiences total internal reflection at the glass-air interface and is trapped in the cell until it eventually escapes from an edge. A VWS device is demonstrated by stacking TIR HPDLCs operating at different wavelengths. Converging or diverging recording beams are employed to fabricate chirped reflection HPDLCs with a pitch gradient along the designated direction, creating chirped switchable reflection gratings (CSRGs). A pixelated version of the CSRG is developed herein, and a dynamic spectral equalizer is presented by combining the pixelated CSRG with a prism (for wavelength discrimination). A switchable circular to point converter (SCPC), which enables the random selection of the wavelength bands divided by the Fabry-Perot interferometer utilizing the controllable beam steering capability of transmission HPDLCs, is demonstrated. A random optical cross-switch (TIROL) can be created by integrating a Fabry-Perot interferometer with a stack of SCPC units. The in-plane electric field generated by the interdigitated electrodes is utilized to elongate the helical pitch of a cholesteric liquid crystal and thereby induces a red shift of the transmission reflection peak

  8. Optimal Placement of Wavelength Converting Nodes

    DEFF Research Database (Denmark)

    Belotti, Pietro; Stidsen, Thomas K.

    2001-01-01

    The all optical network using WDM and optical nodes (OXC's) seems to be a possibility in a near future. The consensus to day seems to be that optical wavelength conversions is un-realistic for several decades, hence wavelength blocking will happen in the all optical networks. A possible solution...... to this problem could be to include digital nodes (DXC's) in the network at the right places. In this article we present a linear programming model which optimizes the placement of these more expensive DXC's in the network....

  9. LUPUS I observations from the 2010 flight of the Balloon-borne large aperture submillimeter telescope for polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Tristan G.; Chapman, Nicholas L.; Novak, Giles [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Ade, Peter A. R.; Hargrave, Peter C.; Nutter, David [Cardiff University, School of Physics and Astronomy, Queens Buildings, The Parade, Cardiff, CF24 3AA (United Kingdom); Angilè, Francesco E.; Devlin, Mark J.; Klein, Jeffrey [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Benton, Steven J.; Fissel, Laura M.; Gandilo, Natalie N.; Netterfield, Calvin B. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street Toronto, ON M5S 3H4 (Canada); Chapin, Edward L. [XMM SOC, ESAC, Apartado 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Fukui, Yasuo [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Gundersen, Joshua O. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Korotkov, Andrei L. [Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912 (United States); Moncelsi, Lorenzo; Mroczkowski, Tony K. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Olmi, Luca [University of Puerto Rico, Rio Piedras Campus, Physics Department, Box 23343, UPR station, San Juan (Puerto Rico); and others

    2014-04-01

    The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was created by adding polarimetric capability to the BLAST experiment that was flown in 2003, 2005, and 2006. BLASTPol inherited BLAST's 1.8 m primary and its Herschel/SPIRE heritage focal plane that allows simultaneous observation at 250, 350, and 500 μm. We flew BLASTPol in 2010 and again in 2012. Both were long duration Antarctic flights. Here we present polarimetry of the nearby filamentary dark cloud Lupus I obtained during the 2010 flight. Despite limitations imposed by the effects of a damaged optical component, we were able to clearly detect submillimeter polarization on degree scales. We compare the resulting BLASTPol magnetic field map with a similar map made via optical polarimetry. (The optical data were published in 1998 by J. Rizzo and collaborators.) The two maps partially overlap and are reasonably consistent with one another. We compare these magnetic field maps to the orientations of filaments in Lupus I, and we find that the dominant filament in the cloud is approximately perpendicular to the large-scale field, while secondary filaments appear to run parallel to the magnetic fields in their vicinities. This is similar to what is observed in Serpens South via near-IR polarimetry, and consistent with what is seen in MHD simulations by F. Nakamura and Z. Li.

  10. Random-phase metasurfaces at optical wavelengths

    DEFF Research Database (Denmark)

    Pors, Anders; Ding, Fei; Chen, Yiting

    2016-01-01

    of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light...

  11. Short wavelength free electron lasers in 1998

    OpenAIRE

    Colson, W.B.

    1999-01-01

    A table is presented that describes the characteristics of 58 short wavelength free electron lasers, operating and proposed, around the world. The author is grateful for support of this work by the Naval Postgraduate School and the Directed Energy Weapons Group, SPAWAR, U.S. Navy.

  12. Novel Wavelength Standards in the Near IR

    Science.gov (United States)

    2008-04-15

    standards is to support the optical telecommunications industry and especially dense wavelength division multiplexing ( DWDM ). Indeed, many commercially...of Standards and Technology (NIST) to have absorption lines known to 130 MHz, or is some cases 13 MHz [1, 8]. Some applications of DWDM call for

  13. Meter wavelength radio astronomy in Chile.

    Science.gov (United States)

    May, J.; Reyes, F.; Alvarez, H.; Aparici, J.; Carr, T.; Phillips, J.; Levy, J.; Lebo, G.

    Current meter-wavelength research at Maipu consists largely of a galactic survey for the southern sky, a search for secondary calibration sources, pulsar studies, a search for atmospheric pulses from Saturn, and the continuing investigation of Jovian S bursts above 30 MHz.

  14. Alien wavelength modeling tool and field trial

    DEFF Research Database (Denmark)

    Sambo, N.; Sgambelluri, A.; Secondini, M.

    2015-01-01

    A modeling tool is presented for pre-FEC BER estimation of PM-QPSK alien wavelength signals. A field trial is demonstrated and used as validation of the tool's correctness. A very close correspondence between the performance of the field trial and the one predicted by the modeling tool has been...

  15. Smart wavelength meter for integrated photonics

    NARCIS (Netherlands)

    Benelajla, Meryem; Taballione, Caterina; Boller, Klaus J.

    2017-01-01

    Thermally tunable SiN waveguide microring resonators in connection with neural network readout algorithms appear promising for use as integrated optical wavelength meters. So far, we have observed long-term reliability and a temperature immunity of the readout across several degrees of ambient

  16. Recent results on measurement of plasma conductivity using Faraday rotation of submillimeter waves

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmenko, P.J.; Self, S.A.

    1982-01-01

    This paper examines the application of Faraday rotation to the measurement of electron concentration in combustion MHD plasmas. Details on the design of a working system are given including the selection of operating wavelength. A theoretical comparison between the Faraday rotation technique and two path interferometry shows Faraday rotation in its simplest form to be somewhat less sensitive to changes in electron concentration. This deficit can be balanced against greater immunity to vibration and thermal drift. Improved techniques of measuring the rotation angle promise greater sensitivity. A preliminary experiment has verified the technique.

  17. SUB-MILLIMETER TELESCOPE CO (2-1) OBSERVATIONS OF NEARBY STAR-FORMING GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xue-Jian; Gu, Qiusheng [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wang, Zhong [Harvard-Smithsonian Center for Astrophysics, MS 66, 60 Garden Street, Cambridge, MA 02138 (United States); Wang, Junzhi [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Zhang, Zhi-Yu, E-mail: xjjiang@nju.edu.cn [The UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)

    2015-01-20

    We present CO J = 2-1 observations toward 32 nearby gas-rich star-forming galaxies selected from the ALFALFA and Wide-field Infrared Survey Explorer (WISE) catalogs, using the Sub-millimeter Telescope (SMT). Our sample is selected to be dominated by intermediate-M {sub *} galaxies. The scaling relations between molecular gas, atomic gas, and galactic properties (stellar mass, NUV – r, and WISE color W3 – W2) are examined and discussed. Our results show the following. (1) In the galaxies with stellar mass M {sub *} ≤10{sup 10} M {sub ☉}, the H I fraction (f {sub H} {sub I} ≡ M {sub H} {sub I}/M {sub *}) is significantly higher than that of more massive galaxies, while the H{sub 2} gas fraction (f{sub H{sub 2}} ≡ M{sub H{sub 2}}/M {sub *}) remains nearly unchanged. (2) Compared to f{sub H{sub 2}}, f {sub H} {sub I} correlates better with both M {sub *} and NUV – r. (3) A new parameter, WISE color W3 – W2 (12-4.6 μm), is introduced, which is similar to NUV – r in tracing star formation activity, and we find that W3 – W2 has a tighter anti-correlation with log f{sub H{sub 2}} than the anti-correlation of (NUV – r)-f {sub H} {sub I}, (NUV – r)-f{sub H{sub 2}}, and (W3 – W2)-f {sub H} {sub I}. This indicates that W3 – W2 can trace the H{sub 2} fraction in galaxies. For the gas ratio M{sub H{sub 2}}/M {sub H} {sub I} , only in the intermediate-M {sub *} galaxies it appears to depend on M {sub *} and NUV – r. We find a tight correlation between the molecular gas mass M{sub H{sub 2}} and 12 μm (W3) luminosities (L {sub 12} {sub μm}), and the slope is close to unity (1.03 ± 0.06) for the SMT sample. This correlation may reflect that the cold gas and dust are well mixed on a global galactic scale. Using the all-sky 12 μm (W3) data available in WISE, this correlation can be used to estimate CO flux for molecular gas observations and can even predict H{sub 2} mass for star-forming galaxies.

  18. Submillimeter H2O and H2O+emission in lensed ultra- and hyper-luminous infrared galaxies at z 2-4

    NARCIS (Netherlands)

    Yang, C.; Omont, A.; Beelen, A.; González-Alfonso, E.; Neri, R.; Gao, Y.; van der Werf, P.; Weiß, A.; Gavazzi, R.; Falstad, N.; Baker, A. J.; Bussmann, R. S.; Cooray, A.; Cox, P.; Dannerbauer, H.; Dye, S.; Guélin, M.; Ivison, R.; Krips, M.; Lehnert, M.; Michałowski, M. J.; Riechers, D. A.; Spaans, M.; Valiante, E.

    2016-01-01

    We report rest-frame submillimeter H2O emission line observations of 11 ultra- or hyper-luminous infrared galaxies (ULIRGs or HyLIRGs) at z 2-4 selected among the brightest lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Using the IRAM NOrthern

  19. THE SCUBA-2 COSMOLOGY LEGACY SURVEY: MULTIWAVELENGTH COUNTERPARTS TO 10{sup 3} SUBMILLIMETER GALAXIES IN THE UKIDSS-UDS FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chian-Chou; Smail, Ian; Ma, Cheng-Jiun; Simpson, James M.; Swinbank, A. Mark [Centre for Extragalactic Astronomy, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Ivison, Rob J.; Arumugam, Vinodiran; Mortlock, Alice; Dunlop, James S.; Michałowski, Michał J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Almaini, Omar; Conselice, Christopher J.; Hartley, Will G. [University of Nottingham, School of Physics and Astronomy, Nottingham, NG7 2RD (United Kingdom); Geach, James E. [Center for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Simpson, Chris [Astrophysics Research Institute, Liverpool John Moores University, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Aretxaga, Itziar [Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Luis Enrique Erro 1, Sta. Ma. Tonantzintla, Puebla (Mexico); Blain, Andrew [Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Chapman, Scott C. [Department of Physics and Atmospheric Science, Dalhousie University, 6310 Coburg Road, Halifax, NS B3H 4R2 (Canada); Farrah, Duncan [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Halpern, Mark [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); and others

    2016-04-01

    We present multiwavelength identifications for the counterparts of 1088 submillimeter sources detected at 850 μm in the SCUBA-2 Cosmology Legacy Survey study of the UKIRT Infrared Deep Sky Survey-Ultra-Deep Survey (UDS) field. By utilizing an Atacama Large Millimeter Array (ALMA) pilot study on a subset of our bright SCUBA-2 sample as a training set, along with the deep optical–near-infrared (OIR) data available in this field, we develop a novel technique, Optical–IR Triple Color (OIRTC), using z − K, K − [3.6], [3.6] − [4.5] colors to select the candidate submillimeter galaxy (SMG) counterparts. By combining radio identification and the OIRTC technique, we find counterpart candidates for 80% of the Class = 1 ≥ 4σ SCUBA-2 sample, defined as those that are covered by both radio and OIR imaging and the base sample for our scientific analyses. Based on the ALMA training set, we expect the accuracy of these identifications to be 82% ± 20%, with a completeness of 69% ± 16%, essentially as accurate as the traditional p-value technique but with higher completeness. We find that the fraction of SCUBA-2 sources having candidate counterparts is lower for fainter 850 μm sources, and we argue that for follow-up observations sensitive to SMGs with S{sub 850} ≳ 1 mJy across the whole ALMA beam, the fraction with multiple counterparts is likely to be >40% for SCUBA-2 sources at S{sub 850} ≳ 4 mJy. We find that the photometric redshift distribution for the SMGs is well fit by a lognormal distribution, with a median redshift of z = 2.3 ± 0.1. After accounting for the sources without any radio and/or OIRTC counterpart, we estimate the median redshift to be z = 2.6 ± 0.1 for SMGs with S{sub 850} > 1 mJy. We also use this new large sample to study the clustering of SMGs and the far-infrared properties of the unidentified submillimeter sources by stacking their Herschel SPIRE far-infrared emission.

  20. Narrow Wavelength, Frequency Modulated Source at 1.5? Wavelength Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA needs narrow linewidth lasers in the 1.5 or 2 micron wavelength regime for Lidar applications. The laser should be tunable by several nm and frequency modulated...

  1. Compact, Wavelength Stabilized Seed Source for Multi-Wavelength Lidar Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA LaRC is developing a compact, multi-wavelength High Spectral resolution Lidar (HSRL) system designed to measure various optical and microphysical properties of...

  2. Far-Field Microscopy of Sparse Subwavelength Objects

    CERN Document Server

    Szameit, A; Dana, H; Steiner, S; Gazit, S; Cohen-Hyams, T; Bullkich, E; Cohen, O; Eldar, Y C; Shoham, S; Kley, E B; Segev, M

    2010-01-01

    We present the experimental reconstruction of sub-wavelength features from the far-field of sparse optical objects. We show that it is sufficient to know that the object is sparse, and only that, and recover 100 nm features with the resolution of 30 nm, for an illuminating wavelength of =532 nm. Our technique works in real-time, requires no scanning, and can be implemented in all existing microscopes - optical and non-optical.

  3. Human wavelength discrimination of monochromatic light explained by optimal wavelength decoding of light of unknown intensity.

    Directory of Open Access Journals (Sweden)

    Li Zhaoping

    Full Text Available We show that human ability to discriminate the wavelength of monochromatic light can be understood as maximum likelihood decoding of the cone absorptions, with a signal processing efficiency that is independent of the wavelength. This work is built on the framework of ideal observer analysis of visual discrimination used in many previous works. A distinctive aspect of our work is that we highlight a perceptual confound that observers should confuse a change in input light wavelength with a change in input intensity. Hence a simple ideal observer model which assumes that an observer has a full knowledge of input intensity should over-estimate human ability in discriminating wavelengths of two inputs of unequal intensity. This confound also makes it difficult to consistently measure human ability in wavelength discrimination by asking observers to distinguish two input colors while matching their brightness. We argue that the best experimental method for reliable measurement of discrimination thresholds is the one of Pokorny and Smith, in which observers only need to distinguish two inputs, regardless of whether they differ in hue or brightness. We mathematically formulate wavelength discrimination under this wavelength-intensity confound and show a good agreement between our theoretical prediction and the behavioral data. Our analysis explains why the discrimination threshold varies with the input wavelength, and shows how sensitively the threshold depends on the relative densities of the three types of cones in the retina (and in particular predict discriminations in dichromats. Our mathematical formulation and solution can be applied to general problems of sensory discrimination when there is a perceptual confound from other sensory feature dimensions.

  4. Cygnus A at 8. 5 millimeter wavelength

    Energy Technology Data Exchange (ETDEWEB)

    Hachenberg, O.; Furst, E.; Harth, W.; Steffen, P.; Wilson, W.; Hirth, W.

    1976-05-15

    The compact central component of Cygnus A was observed at 8.5 mm wavelength with the Effelsberg 100 m telescope. The flux was found to 1.8 +- 0.6 Jy. Including the spectral information already known, a flat or slightly increasing spectrum can be derived in the range from 5 GHz up to 35 GHz. If the measured radiation is interpreted as synchrotron emission, high values of the magnetic field strength and the (relatistic) electron density are needed. (AIP)

  5. Five wavelength DFB fiber lase source

    DEFF Research Database (Denmark)

    Varming, Poul; Hübner, Jörg; Kristensen, M.

    1997-01-01

    Stable single-mode laser sources with narrow linewidth are key components in high-capacity wavelength-division multiplexed (WDM) optical communication systems. Distributed feedback (DFB) and distributed Bragg reflection (DBR) fiber lasers are compact devices, which are able to provide stable sing......-mode operation. They are inherently fiber compatible and cascadable. We present a multiwavelength laser source consisting of five fiber DFB lasers spliced together and pumped by a single 60-mW 1480-nm semiconductor laser...

  6. DUST AND GAS IN THE MAGELLANIC CLOUDS FROM THE HERITAGE HERSCHEL KEY PROJECT. I. DUST PROPERTIES AND INSIGHTS INTO THE ORIGIN OF THE SUBMILLIMETER EXCESS EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, Karl D.; Roman-Duval, Julia; Meixner, Margaret [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bot, Caroline [Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l Université, F-67000 Strasbourg (France); Babler, Brian [Department of Astronomy, 475 North Charter Street, University of Wisconsin, Madison, WI 53706 (United States); Bernard, Jean-Philippe [CESR, Université de Toulouse, UPS, 9 Avenue du Colonel Roche, F-31028 Toulouse, Cedex 4 (France); Bolatto, Alberto; Jameson, Katherine [Department of Astronomy, Lab for Millimeter-wave Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Boyer, Martha L. [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Clayton, Geoffrey C. [Department of Physics and Astronomy, Louisiana State University, 233-A Nicholson Hall, Tower Drive, Baton Rouge, LA 70803 (United States); Engelbracht, Charles [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Fukui, Yasuo [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Galametz, Maud [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching-bei-Mnchen (Germany); Galliano, Frederic; Hony, Sacha; Lebouteiller, Vianney [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Hughes, Annie [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Indebetouw, Remy [Department of Astronomy, University of Virginia, and National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Israel, Frank P. [Sterrewacht Leiden, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Kawamura, Akiko [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo, 181-8588 (Japan); and others

    2014-12-20

    The dust properties in the Large and Small Magellanic clouds (LMC/SMC) are studied using the HERITAGE Herschel Key Project photometric data in five bands from 100 to 500 μm. Three simple models of dust emission were fit to the observations: a single temperature blackbody modified by a power-law emissivity (SMBB), a single temperature blackbody modified by a broken power-law emissivity (BEMBB), and two blackbodies with different temperatures, both modified by the same power-law emissivity (TTMBB). Using these models, we investigate the origin of the submillimeter excess, defined as the submillimeter emission above that expected from SMBB models fit to observations <200 μm. We find that the BEMBB model produces the lowest fit residuals with pixel-averaged 500 μm submillimeter excesses of 27% and 43% for the LMC and SMC, respectively. Adopting gas masses from previous works, the gas-to-dust ratios calculated from our fitting results show that the TTMBB fits require significantly more dust than are available even if all the metals present in the interstellar medium (ISM) were condensed into dust. This indicates that the submillimeter excess is more likely to be due to emissivity variations than a second population of colder dust. We derive integrated dust masses of (7.3 ± 1.7) × 10{sup 5} and (8.3 ± 2.1) × 10{sup 4} M {sub ☉} for the LMC and SMC, respectively. We find significant correlations between the submillimeter excess and other dust properties; further work is needed to determine the relative contributions of fitting noise and ISM physics to the correlations.

  7. Dust and Gas in the Magellanic Clouds from the Heritage Herschel Key Project. I. Dust Properties and Insights into the Origin of the Submm (Submillimeter) Excess Emission

    Science.gov (United States)

    Gordon, Karl D.; Roman-Duval, Julia; Bot, Caroline; Meixner, Margaret; Babler, Brian; Bernard, Jean-Philippe; Bolatto, Alberto; Boyer, Martha L.; Clayton, Geoffrey C.; Engelbracht, Charles; hide

    2014-01-01

    The dust properties in the Large and Small Magellanic Clouds are studied using the HERITAGE Herschel Key Project photometric data in five bands from 100 to 500 micromillimeters. Three simple models of dust emission were fit to the observations: a single temperature blackbody modified by a powerlaw emissivity (SMBB), a single temperature blackbody modified by a broken power-law emissivity (BEMBB), and two blackbodies with different temperatures, both modified by the same power-law emissivity (TTMBB). Using these models we investigate the origin of the submillimeter excess; defined as the submillimeter (submm) emission above that expected from SMBB models fit to observations < 200 micromillimeters. We find that the BEMBB model produces the lowest fit residuals with pixel-averaged 500 micromillimeters submillimeter excesses of 27% and 43% for the Large and Small Magellanic Clouds, respectively. Adopting gas masses from previous works, the gas-to-dust ratios calculated from our fitting results show that the TTMBB fits require significantly more dust than are available even if all the metals present in the interstellar medium (ISM) were condensed into dust. This indicates that the submillimeter excess is more likely to be due to emissivity variations than a second population of colder dust. We derive integrated dust masses of (7.3 plus or minus 1.7) x 10 (sup 5) and (8.3 plus or minus 2.1) x 10 (sup 4) solar masses for the Large and Small Magellanic Clouds, respectively. We find significant correlations between the submillimeter excess and other dust properties; further work is needed to determine the relative contributions of fitting noise and ISM physics to the correlations.

  8. EXPLORING THE RELATION BETWEEN (SUB-)MILLIMETER RADIATION AND {gamma}-RAY EMISSION IN BLAZARS WITH PLANCK AND FERMI

    Energy Technology Data Exchange (ETDEWEB)

    Leon-Tavares, J.; Tornikoski, M.; Laehteenmaeki, A. [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FIN-02540 Kylmaelae (Finland); Valtaoja, E. [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, 20100 Turku (Finland); Giommi, P.; Polenta, G.; Gasparrini, D.; Cutini, S., E-mail: leon@kurp.hut.fi [ASI Science Data Center, ASDC c/o ESRIN, via G. Galilei, 00044 Frascati (Italy)

    2012-07-20

    The coexistence of Planck and Fermi satellites in orbit has enabled the exploration of the connection between the (sub-)millimeter and {gamma}-ray emission in a large sample of blazars. We find that the {gamma}-ray emission and the (sub-)mm luminosities are correlated over five orders of magnitude, L{sub {gamma}}{proportional_to}L{sub (sub-)mm}. However, this correlation is not significant at some frequency bands when simultaneous observations are considered. The most significant statistical correlations, on the other hand, arise when observations are quasi-simultaneous within two months. Moreover, we find that sources with an approximate spectral turnover in the middle of the mm-wave regime are more likely to be strong {gamma}-ray emitters. These results suggest a physical relation between the newly injected plasma components in the jet and the high levels of {gamma}-ray emission.

  9. Fabrication of an absorber-coupled MKID detector and readout for sub-millimeter and far-infrared astronomy

    Science.gov (United States)

    Brown, Ari-David; Hsieh, Wen-Ting; Moseley, S. Harvey; Stevenson, Thomas R.; U-yen, Kongpop; Wollack, Edward J.

    2010-07-01

    We have fabricated absorber-coupled microwave kinetic inductance detector (MKID) arrays for sub-millimeter and farinfrared astronomy. Each detector array is comprised of λ/2 stepped impedance resonators, a 1.5μm thick silicon membrane, and 380μm thick silicon walls. The resonators consist of parallel plate aluminum transmission lines coupled to low impedance Nb microstrip traces of variable length, which set the resonant frequency of each resonator. This allows for multiplexed microwave readout and, consequently, good spatial discrimination between pixels in the array. The Al transmission lines simultaneously act to absorb optical power and are designed to have a surface impedance and filling fraction so as to match the impedance of free space. Our novel fabrication techniques demonstrate high fabrication yield of MKID arrays on large single crystal membranes and sub-micron front-to-back alignment of the microstrip circuit.

  10. Fabrication of an Absorber-Coupled MKID Detector and Readout for Sub-Millimeter and Far-Infrared Astronomy

    Science.gov (United States)

    Brown, Ari-David; Hsieh, Wen-Ting; Moseley, S. Harvey; Stevenson, Thomas R.; U-yen, Kongpop; Wollack, Edward J.

    2010-01-01

    We have fabricated absorber-coupled microwave kinetic inductance detector (MKID) arrays for sub-millimeter and farinfrared astronomy. Each detector array is comprised of lambda/2 stepped impedance resonators, a 1.5µm thick silicon membrane, and 380µm thick silicon walls. The resonators consist of parallel plate aluminum transmission lines coupled to low impedance Nb microstrip traces of variable length, which set the resonant frequency of each resonator. This allows for multiplexed microwave readout and, consequently, good spatial discrimination between pixels in the array. The Al transmission lines simultaneously act to absorb optical power and are designed to have a surface impedance and filling fraction so as to match the impedance of free space. Our novel fabrication techniques demonstrate high fabrication yield of MKID arrays on large single crystal membranes and sub-micron front-to-back alignment of the microstrip circuit.

  11. Hacking for astronomy: can 3D printers and open-hardware enable low-cost sub-/millimeter instrumentation?

    Science.gov (United States)

    Ferkinhoff, Carl

    2014-07-01

    There have been several exciting developments in the technologies commonly used n in the hardware hacking community. Advances in low cost additive-manufacturing processes (i.e. 3D-printers) and the development of openhardware projects, which have produced inexpensive and easily programmable micro-controllers and micro-computers (i.e. Arduino and Raspberry Pi) have opened a new door for individuals seeking to make their own devices. Here we describe the potential for these technologies to reduce costs in construction and development of submillimeter/millimeter astronomical instrumentation. Specifically we have begun a program to measure the optical properties of the custom plastics used in 3D-printers as well as the printer accuracy and resolution to assess the feasibility of directly printing sub- /millimeter transmissive optics. We will also discuss low cost designs for cryogenic temperature measurement and control utilizing Arduino and Raspberry Pi.

  12. Detection of Submillimeter-wave [C i] Emission in Gaseous Debris Disks of 49 Ceti and β Pictoris

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, Aya E.; Sakai, Nami [The Institute of Physical and Chemical Research (RIKEN), 2-1, Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Sato, Aki; Tsukagoshi, Takashi; Momose, Munetake [College of Science, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512 (Japan); Iwasaki, Kazunari [Department of Environmental Systems Science, Doshisha University, Tatara Miyakodani 1-3, Kyotanabe City, Kyoto 610-0394 (Japan); Kobayashi, Hiroshi; Ishihara, Daisuke; Watanabe, Sakae; Kaneda, Hidehiro [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan); Yamamoto, Satoshi, E-mail: aya.higuchi@riken.jp [Department of Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2017-04-10

    We have detected [C i] {sup 3} P {sub 1}–{sup 3} P {sub 0} emissions in the gaseous debris disks of 49 Ceti and β Pictoris with the 10 m telescope of the Atacama Submillimeter Telescope Experiment, which is the first detection of such emissions. The line profiles of [C i] are found to resemble those of CO( J = 3–2) observed with the same telescope and the Atacama Large Millimeter/submillimeter Array. This result suggests that atomic carbon (C) coexists with CO in the debris disks and is likely formed by the photodissociation of CO. Assuming an optically thin [C i] emission with the excitation temperature ranging from 30 to 100 K, the column density of C is evaluated to be (2.2 ± 0.2) × 10{sup 17} and (2.5 ± 0.7) × 10{sup 16} cm{sup −2} for 49 Ceti and β Pictoris, respectively. The C/CO column density ratio is thus derived to be 54 ± 19 and 69 ± 42 for 49 Ceti and β Pictoris, respectively. These ratios are higher than those of molecular clouds and diffuse clouds by an order of magnitude. The unusually high ratios of C to CO are likely attributed to a lack of H{sub 2} molecules needed to reproduce CO molecules efficiently from C. This result implies a small number of H{sub 2} molecules in the gas disk, i.e., there is an appreciable contribution of secondary gas from dust grains.

  13. Sensitivity of blackbody effective emissivity to wavelength and temperature: By genetic algorithm

    Science.gov (United States)

    Ejigu, E. K.; Liedberg, H. G.

    2013-09-01

    A variable-temperature blackbody (VTBB) is used to calibrate an infrared radiation thermometer (pyrometer). The effective emissivity (ɛeff) of a VTBB is dependent on temperature and wavelength other than the geometry of the VTBB. In the calibration process the effective emissivity is often assumed to be constant within the wavelength and temperature range. There are practical situations where the sensitivity of the effective emissivity needs to be known and correction has to be applied. We present a method using a genetic algorithm to investigate the sensitivity of the effective emissivity to wavelength and temperature variation. Two matlab® programs are generated: the first to model the radiance temperature calculation and the second to connect the model to the genetic algorithm optimization toolbox. The effective emissivity parameter is taken as a chromosome and optimized at each wavelength and temperature point. The difference between the contact temperature (reading from a platinum resistance thermometer or liquid in glass thermometer) and radiance temperature (calculated from the ɛeff values) is used as an objective function where merit values are calculated and best fit ɛeff values selected. The best fit ɛeff values obtained as a solution show how sensitive they are to temperature and wavelength parameter variation. Uncertainty components that arise from wavelength and temperature variation are determined based on the sensitivity analysis. Numerical examples are considered for illustration.

  14. Sensitivity of blackbody effective emissivity to wavelength and temperature: By genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Ejigu, E. K.; Liedberg, H. G. [National Metrology Institute of South Africa (NMISA), Private Bag X34, Lynnwood Ridge, Pretoria, 0040 (South Africa)

    2013-09-11

    A variable-temperature blackbody (VTBB) is used to calibrate an infrared radiation thermometer (pyrometer). The effective emissivity (ε{sub eff}) of a VTBB is dependent on temperature and wavelength other than the geometry of the VTBB. In the calibration process the effective emissivity is often assumed to be constant within the wavelength and temperature range. There are practical situations where the sensitivity of the effective emissivity needs to be known and correction has to be applied. We present a method using a genetic algorithm to investigate the sensitivity of the effective emissivity to wavelength and temperature variation. Two matlab® programs are generated: the first to model the radiance temperature calculation and the second to connect the model to the genetic algorithm optimization toolbox. The effective emissivity parameter is taken as a chromosome and optimized at each wavelength and temperature point. The difference between the contact temperature (reading from a platinum resistance thermometer or liquid in glass thermometer) and radiance temperature (calculated from the ε{sub eff} values) is used as an objective function where merit values are calculated and best fit ε{sub eff} values selected. The best fit ε{sub eff} values obtained as a solution show how sensitive they are to temperature and wavelength parameter variation. Uncertainty components that arise from wavelength and temperature variation are determined based on the sensitivity analysis. Numerical examples are considered for illustration.

  15. Wavelength Converters Placement in Optical Networks Using Bee Colony Optimization

    Directory of Open Access Journals (Sweden)

    MARKOVIC, G. Z.

    2016-02-01

    Full Text Available Wavelength converters placement (WCP in all-optical WDM networks belongs to the class of hard combinatorial optimization problems. So far, this problem has been solved by various heuristic strategies or by application of metaheuristic approaches such as genetic algorithms (GA, particle swarm optimization (PSO, differential evolution (DE, etc. In this paper, we introduce the application of Bee Colony Optimization (BCO metaheuristic to solve the WCP problem in all-optical WDM networks. Numerous studies prove that BCO is a fast, robust and computationally efficient tool in tackling complex optimization problems. The objective of the proposed BCO-WCP algorithm is to find the best placement of limited number of wavelength converters in given optical network such that the overall network blocking probability is minimized. To evaluate the performances of the BCO-WCP algorithm, numerous simulation experiments have been performed over some realistic optical network examples. The blocking probability performance and computational complexity are compared with optimal solution obtained by exhaustive search (ES approach as well as with DE and PSO metaheuristics. It will be shown that the BCO-WCP algorithm is not only be able to produce high quality (optimal solution, but significantly outperforms the computational efficiency of other considered approaches.

  16. An object-color space.

    Science.gov (United States)

    Logvinenko, Alexander D

    2009-10-05

    Putting aside metaphorical meanings of the term, color space is understood as a vector space, where lights having the same color (i.e., subjectively indistinguishable) are represented as a point. The CIE 1931 color space, empirically based on trichromatic color measurements, is a classical example. Its derivatives, such as CIELAB and sRGB, have been successfully used in many applications (e.g., in color management). However, having been designed for presenting the color of self-luminous objects, these spaces are less suitable for presenting color of reflecting objects. Specifically, they can be used to represent color of objects only for a fixed illumination. Here I put forward a color space to represent the color of objects independently of illumination. It is based on an ideal color atlas comprising the reflectance spectra taking two values: k or 1 - k (0 color atlas is complete; that is, every reflecting object is metameric to some element of the atlas. When illumination alters, the classes of metameric reflectance spectra are reshuffled but in each class there is exactly one element of the atlas. Hence, the atlas can uniquely represent the metameric classes irrespective of illumination. Each element of the atlas (thus, object color) is specified by three numbers: (i) lambda = (lambda(1) + lambda(2))/2, which correlates well with hue of object color (as dominant wavelength correlates with hue of light color); (ii) delta =/lambda(1) - lambda/, which correlates with whiteness/blackness; and (iii) alpha =/1 - 2k/, which correlates with chroma of object color (as colorimetric purity correlates with saturation of light color). Using a geographical coordinate system, each element of the atlas (thus, each object color) is geometrically represented as a radius vector so that its length equals alpha, the latitude and longitude being proportional to delta and lambda, respectively.

  17. Wavelength-agnostic WDM-PON System

    DEFF Research Database (Denmark)

    Wagner, Christoph; Eiselt, Michael; Zou, S.

    2016-01-01

    Next-generation WDM-PON solutions for metro and access systems will take advantage of remotely controlled wavelength-tunable ONUs to keep system costs as low as possible. For such a purpose, each ONU signal can be labeled by a pilot tone modulated onto the optical data stream. We report...... on the standardization status of this lowcost system in the new ITU-T G.metro draft recommendation, in the context of autonomous tuning. We also discuss some low-effort implementations of the pilot-tone labels and investigate the impact of these labels on the transmission channels....

  18. Topology Optimization of Sub-Wavelength Antennas

    DEFF Research Database (Denmark)

    Erentok, Aycan; Sigmund, Ole

    2011-01-01

    We propose a topology optimization strategy for the systematic design of a three-dimensional (3D), conductor-based sub-wavelength antenna. The post-processed finite-element (FE) models of the optimized structure are shown to be self-resonant, efficient and exhibit distorted omnidirectional......, elliptically polarized far-field radiation patterns. The computed approximate Q value for this antenna is QZ(ω0)≈ 7.74 for ω0=2π × 350.8 MHz and it is 1.64 times larger than the theoretical lower bound value....

  19. 1550-nm wavelength-tunable HCG VCSELs

    Science.gov (United States)

    Chase, Christopher; Rao, Yi; Huang, Michael; Chang-Hasnain, Connie

    2014-02-01

    We demonstrate wavelength-tunable VCSELs using high contrast gratings (HCGs) as the top output mirror on VCSELs, operating at 1550 nm. Tunable HCG VCSELs with a ~25 nm mechanical tuning range as well as VCSELs with 2 mW output power were realized. Error-free operation of an optical link using directly-modulated tunable HCG VCSELs transmitting at 1.25 Gbps over 18 channels spaced by 100 GHz and transmitted over 20 km of single mode fiber is demonstrated, showing the suitability of the HCG tunable VCSEL as a low cost source for WDM communications systems.

  20. Gold Photoluminescence: Wavelength and Polarization Engineering

    DEFF Research Database (Denmark)

    Andersen, Sebastian Kim Hjælm; Pors, Anders Lambertus; Bozhevolnyi, Sergey I.

    2015-01-01

    We demonstrate engineering of the spectral content and polarization of photoluminescence (PL) from arrayed gold nanoparticles atop a subwavelength-thin dielectric spacer and optically-thick gold film, a configuration that supports gap-surface plasmon resonances (GSPRs). Choice of shapes...... and dimensions of gold nanoparticles influences the GSPR wavelength and polarization characteristics, thereby allowing us to enhance and spectrally mold the plasmon-assisted PL while simultaneously controlling its polarization. In order to understand the underlying physics behind the plasmon-enhanced PL, we...

  1. Wavelength conversion in optical packet switching

    DEFF Research Database (Denmark)

    Danielsen, Søren Lykke; Hansen, Peter Bukhave; Stubkjær, Kristian

    1998-01-01

    A detailed traffic analysis of optical packet switch design is performed. Special consideration is given to the complexity of the optical buffering and the overall switch block structure is considered in general. Wavelength converters are shown to improve the traffic performance of the switch...... blocks for both random and bursty traffic. Furthermore, the traffic performance of switch blocks with add-drop switches has been assessed in a Shufflenetwork showing the advantage of having converters at the inlets. Finally, the aspect of synchronization is discussed through a proposal to operate...... the packet switch block asynchronously, i.e. without packet alignment at the input...

  2. Wavelength and End Correction in a Recorder

    Directory of Open Access Journals (Sweden)

    Shuaihang (Susan Wang

    2009-01-01

    Full Text Available The wavelength and end correction was investigated as a function of the tube length of a recorder over a range of frequencies. It was found that the period of the sound produced varies linearly with the recorder’s tube length, as expected. It was also found that the end correction does not vary as a function of frequency. However, the end correction at the hole was found to be much greater than the end correction at the end of a resonating tube.

  3. Dual-wavelength InP quantum dot lasers

    Energy Technology Data Exchange (ETDEWEB)

    Shutts, S.; Smowton, P. M. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Krysa, A. B. [EPSRC National Centre for III-V Technologies, Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2014-06-16

    We have demonstrated a two-section dual-wavelength diode laser incorporating distributed Bragg reflectors, with a peak-wavelength separation of 62.5 nm at 300 K. Each lasing wavelength has a different temperature dependence, providing a difference-tuning of 0.11 nm/K. We discuss the mechanisms governing the light output of the two competing modes and explain how the short wavelength can be relatively insensitive to output changes at the longer wavelength. Starting from an initial condition when the output at both wavelengths are equal, a 500% increase in the long wavelength output causes the short wavelength output to fall by only 6%.

  4. Passively synchronized dual-wavelength Q-switched lasers

    DEFF Research Database (Denmark)

    Janousek, Jiri; Tidemand-Lichtenberg, Peter; Mortensen, Jesper Liltorp

    We present a simple and efficient way of generating synchronized Q-switched pulses at wavelengths hundreds of nanometers apart. This principle can result in new pulsed all-solid-state light sources at new wavelengths based on SFG....

  5. Outflow and accretion detections in the young stellar object IRAS 04579+4703

    OpenAIRE

    Xu, Jin-Long; Wang, Jun-jie; Qin, Sheng-Li

    2012-01-01

    We present Submillimeter Array observations of the young stellar object IRAS 04579+4703 in the 1.3 mm continuum and in the 12CO(2-1), 13CO(2-1) and C18O(2-1) lines. The 1.3 mm continuum image reveals a flattened structure with a mass of 13 Msun. The 12CO(2-1) line map and position-velocity (PV) diagram, together with the broad wing (full width=30 km/s of 12CO(2-1)) line, clearly show that there is an outflow motion, which originates from an embedded massive YSO in this region. The lengths of ...

  6. The rotating molecular core and precessing outflow of the young stellar object Barnard 1c

    OpenAIRE

    B. C. Matthews; Hogerheijde, M. R.; Jorgensen, J. K.; Bergin, E. A.

    2006-01-01

    We investigate the structure of the core surrounding the recently identified deeply embedded young stellar object Barnard 1c which has an unusual polarization pattern as traced in submillimeter dust emission. Barnard 1c lies within the Perseus molecular cloud at a distance of 250 pc. It is a deeply embedded core of 2.4 solar masses (Kirk et al.) and a luminosity of 4 +/- 2 solar luminosities. Observations of CO, 13CO, C18O, HCO+ and N2H+ were obtained with the BIMA array, together with the co...

  7. Coherence techniques at extreme ultraviolet wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chang [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    The renaissance of Extreme Ultraviolet (EUV) and soft x-ray (SXR) optics in recent years is mainly driven by the desire of printing and observing ever smaller features, as in lithography and microscopy. This attribute is complemented by the unique opportunity for element specific identification presented by the large number of atomic resonances, essentially for all materials in this range of photon energies. Together, these have driven the need for new short-wavelength radiation sources (e.g. third generation synchrotron radiation facilities), and novel optical components, that in turn permit new research in areas that have not yet been fully explored. This dissertation is directed towards advancing this new field by contributing to the characterization of spatial coherence properties of undulator radiation and, for the first time, introducing Fourier optical elements to this short-wavelength spectral region. The first experiment in this dissertation uses the Thompson-Wolf two-pinhole method to characterize the spatial coherence properties of the undulator radiation at Beamline 12 of the Advanced Light Source. High spatial coherence EUV radiation is demonstrated with appropriate spatial filtering. The effects of small vertical source size and beamline apertures are observed. The difference in the measured horizontal and vertical coherence profile evokes further theoretical studies on coherence propagation of an EUV undulator beamline. A numerical simulation based on the Huygens-Fresnel principle is performed.

  8. Tuning Metamaterials for Applications at DUV Wavelengths

    Directory of Open Access Journals (Sweden)

    Andrew Estroff

    2012-01-01

    Full Text Available The unique properties of metamaterials, namely, their negative refractive index, permittivity, or permeability, have gained much recent attention. Research into these materials has led to the realization of a host of applications that may be useful to enhance optical nanolithography. A selection of materials has been examined both experimentally and theoretically to verify their support of surface plasmons, or lack thereof, in the DUV spectrum via the attenuated total reflection (ATR method using the Kretschmann configuration. At DUV wavelengths, materials that were previously useful at mid-UV and longer wavelengths no longer act as metamaterials. Structured materials comprised of alternating layers of aluminum and aluminum oxide (Al2O3, as well as some other absorption-free dielectrics, exhibit metamaterial behavior, as do some elemental materials such as aluminum. These elemental and structured materials exhibit the best properties for use in plasmonic nanolithographic applications. Therefore, a simulator was created to examine material and thickness combinations to generate a tunable metamaterial for use in the DUV. A method for performing plasmonic interference lithography with this metamaterial has been proposed, with calculations showing the potential for half-pitch imaging resolution of 25 nm.

  9. Multi-wavelength observations of the enduring type IIn Supernovae 2005ip and 2006jd

    DEFF Research Database (Denmark)

    Stritzinger, Maximilian; Taddia, Francesco; Fransson, Claes

    2012-01-01

    extend from UV to mid-infrared wavelengths, and like SN 2005ip, are compared to reported X-ray measurements to understand the nature of the progenitor. Both objects display a number of similarities with the 1988Z-like subclass of SN IIn including (1) remarkably similar early-and late-phase optical......We present an observational study of the Type IIn supernovae (SNe IIn) 2005ip and 2006jd. Broadband UV, optical, and near-IR photometry, and visual-wavelength spectroscopy of SN 2005ip complement and extend upon published observations to 6.5 years past discovery. Our observations of SN 2006jd...

  10. Sound objects – Auditory objects – Musical objects

    DEFF Research Database (Denmark)

    Hjortkjær, Jens

    2015-01-01

    ’. In this paper, I review recent neurocognitive research suggesting that the auditory system is sensitive to structural information about real-world objects. Instead of focusing solely on perceptual sound features as determinants of auditory objects, I propose that real-world object properties are inherent......The auditory system transforms patterns of sound energy into perceptual objects but the precise definition of an ‘auditory object’ is much debated. In the context of music listening, Pierre Schaeffer argued that ‘sound objects’ are the fundamental perceptual units in ‘musical objects...

  11. Sound objects – Auditory objects – Musical objects

    DEFF Research Database (Denmark)

    Hjortkjær, Jens

    2016-01-01

    ’. In this paper, I review recent neurocognitive research suggesting that the auditory system is sensitive to structural information about real-world objects. Instead of focusing solely on perceptual sound features as determinants of auditory objects, I propose that real-world object properties are inherent......The auditory system transforms patterns of sound energy into perceptual objects but the precise definition of an ‘auditory object’ is much debated. In the context of music listening, Pierre Schaeffer argued that ‘sound objects’ are the fundamental perceptual units in ‘musical objects...

  12. Resonant behavior of dielectric objects (electrostatic resonances).

    Science.gov (United States)

    Fredkin, D R; Mayergoyz, I D

    2003-12-19

    Resonant behavior of dielectric objects occurs at certain frequencies for which the object permittivity is negative and the free-space wavelength is large in comparison with the object dimensions. Unique physical features of these resonances are studied and a novel technique for the calculation of resonance values of permittivity, and hence resonance frequencies, is proposed. Scale invariance of resonance frequencies, unusually strong orthogonality properties of resonance modes, and a two-dimensional phenomenon of "twin" spectra are reported. The paper concludes with brief discussions of optical controllability of these resonances in semiconductor nanoparticles and a plausible, electrostatic resonance based, mechanism for nucleation and formation of ball lightning.

  13. Dynamic Sensor Interrogation Using Wavelength-Swept Laser with a Polygon-Scanner-Based Wavelength Filter

    Directory of Open Access Journals (Sweden)

    Kyung Hyun Park

    2013-07-01

    Full Text Available We report a high-speed (~2 kHz dynamic multiplexed fiber Bragg grating (FBG sensor interrogation using a wavelength-swept laser (WSL with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement.

  14. Dynamic sensor interrogation using wavelength-swept laser with a polygon-scanner-based wavelength filter.

    Science.gov (United States)

    Kwon, Yong Seok; Ko, Myeong Ock; Jung, Mi Sun; Park, Ik Gon; Kim, Namje; Han, Sang-Pil; Ryu, Han-Cheol; Park, Kyung Hyun; Jeon, Min Yong

    2013-07-29

    We report a high-speed (~2 kHz) dynamic multiplexed fiber Bragg grating (FBG) sensor interrogation using a wavelength-swept laser (WSL) with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement.

  15. Laboratory permittivity measurements of icy planetary analogs in the millimeter and submillimeter domains, in relation with JUICE mission.

    Science.gov (United States)

    Brouet, Y.; Jacob, K.; Murk, A.; Poch, O.; Pommerol, A.; Thomas, N.; Levasseur-Regourd, A. C.

    2015-12-01

    The European Space Agency's JUpiter ICy moons Explorer (JUICE) spacecraft is planned for launch in 2022 and arrival at Jupiter in 2030. It will observe the planet Jupiter and three of its largest moons, Ganymede, Callisto and Europa. One instrument on the JUICE spacecraft is the Sub-millimeter Wave Instrument (SWI), which will measure brightness temperatures from Jupiter's stratosphere and troposphere, and from subsurfaces of Jupiter's icy moons. In the baseline configuration SWI consists of two tunable sub-millimeter wave receivers operating from 530 to 625 GHz. As an alternative one of the receivers could cover the range of 1080 and 1275 GHz. Inversion models are strongly dependent on the knowledge of the complex relative permittivity (hereafter permittivity) of the target material to retrieve the physical properties of the subsurface (e.g. [1][2]). We set up a laboratory experiment allowing us to perform reproducible measurements of the complex scattering parameters S11 and S21 in the ranges of 70 to 110 GHz, of 100 to 160 GHz, of 140 to 220 GHz, of 140 to 220 GHz and of 510 to 715 GHz. These scattering parameters can be used to retrieve the permittivity of icy analogs of the surfaces and subsurfaces of Jupiter's icy moons in order to prepare the data interpretation of SWI [3]. The measurements are performed under laboratory conditions with a quasi-optical bench (Institute of Applied Physics, University of Bern). The icy analogs that we prepare in the Laboratory for Outflow Studies of Sublimating Materials (LOSSy, Physics Institute, University of Bern), include two different porous water ice samples composed of fine-grained ice particles with a size range of 4 to 6 microns and ice particles with a size range of 50 to 100 microns [4][5]; and possibly CO2 ice. We will present the general experimental set-up and the first results in the context to prepare the data interpretation of SWI. [1] Ulaby, F. T., Long, D. G., 2014. Microwave radar and radiometric remote

  16. AN ALMA SURVEY OF SUBMILLIMETER GALAXIES IN THE EXTENDED CHANDRA DEEP FIELD SOUTH: NEAR-INFRARED MORPHOLOGIES AND STELLAR SIZES

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chian-Chou; Smail, Ian; Swinbank, A. M.; Simpson, J. M.; Ma, Cheng-Jiun; Alexander, D. M.; Danielson, A. L. R.; Edge, A. C. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Biggs, A. D.; Ivison, R. J. [European Southern Observatory, Karl Schwarzschild Strasse 2, D-85748 Garching (Germany); Brandt, W. N. [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 3J5 (Canada); Coppin, K. E. K. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Dannerbauer, H. [Institut für Astrophysik, Universität Wien, Türkenschanzstraße 17, A-1180 Wien (Austria); Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Karim, A. [Argelander-Institute for Astronomy, Bonn University, Auf dem Hügel 71, D-53121 Bonn (Germany); Menten, Karl M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Schinnerer, E.; Walter, F. [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Wardlow, J. L. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); and others

    2015-02-01

    We analyze Hubble Space Telescope WFC3/H {sub 160}-band observations of a sample of 48 Atacama Large Millimeter/submillimeter Array detected submillimeter galaxies (SMGs) in the Extended Chandra Deep Field South field, to study their stellar morphologies and sizes. We detect 79% ± 17% of the SMGs in the H {sub 160}-band imaging with a median sensitivity of 27.8 mag, and most (80%) of the nondetections are SMGs with 870 μm fluxes of S {sub 870} < 3 mJy. With a surface brightness limit of μ {sub H} ∼ 26 mag arcsec{sup –2}, we find that 82% ± 9% of the H {sub 160}-band-detected SMGs at z = 1-3 appear to have disturbed morphologies, meaning they are visually classified as either irregulars or interacting systems, or both. By determining a Sérsic fit to the H {sub 160} surface brightness profiles, we derive a median Sérsic index of n = 1.2 ± 0.3 and a median half-light radius of r{sub e} = 4.4{sub −0.5}{sup +1.1} kpc for our SMGs at z = 1-3. We also find significant displacements between the positions of the H {sub 160} component and 870 μm emission in these systems, suggesting that the dusty starburst regions and less-obscured stellar distribution are not colocated. We find significant differences in the sizes and the Sérsic index between our z = 2-3 SMGs and z ∼ 2 quiescent galaxies, suggesting that a major transformation of the stellar light profile is needed in the quenching processes if SMGs are progenitors of the red-and-dead z ∼ 2 galaxies. Given the short-lived nature of SMGs, we postulate that the majority of the z = 2-3 SMGs with S {sub 870} ≳ 2 mJy are early/mid-stage major mergers.

  17. Dual wavelength full field imaging in low coherence digital holographic microscopy.

    Science.gov (United States)

    Monemhaghdoust, Zahra; Montfort, Frédéric; Emery, Yves; Depeursinge, Christian; Moser, Christophe

    2011-11-21

    A diffractive optical element (DOE) is presented to simultaneously manipulate the coherence plane tilt of a beam containing a plurality of discrete wavelengths. The DOE is inserted into the reference arm of an off-axis dual wavelength low coherence digital holographic microscope (DHM) to provide a coherence plane tilt so that interference with the object beam generates fringes over the full detector area. The DOE maintains the propagation direction of the reference beam and thus it can be inserted in-line in existing DHM set-ups. We demonstrate full field imaging in a reflection commercial DHM with two wavelengths, 685 nm and 794 nm, resulting in an unambiguous range of 2.494 micrometers. © 2011 Optical Society of America

  18. Long-Wavelength Beam Steerer Based on a Micro-Electromechanical Mirror.

    Science.gov (United States)

    Kos, Anthony B; Gerecht, Eyal

    2013-01-01

    Commercially available mirrors for scanning long-wavelength beams are too large for high-speed imaging. There is a need for a smaller, more agile pointing apparatus to provide images in seconds, not minutes or hours. A fast long-wavelength beam steerer uses a commercial micro-electro-mechanical system (MEMS) mirror controlled by a high-performance digital signal processor (DSP). The DSP allows high-speed raster scanning of the incident radiation, which is focused to a small waist onto the 9mm(2), gold-coated, MEMS mirror surface, while simultaneously acquiring an undistorted, high spatial-resolution image of an object. The beam steerer hardware, software and performance are described. The system can also serve as a miniaturized, high-performance long-wavelength beam chopper for lock-in detection.

  19. Prototype for Long Wavelength Array Sees First Light

    Science.gov (United States)

    2007-03-01

    Astronomers at the Naval Research Laboratory have produced the first images of the sky from a prototype of the Long Wavelength Array (LWA), a revolutionary new radio telescope to be constructed in southwestern New Mexico. The images show emissions from the center of our Galaxy, a supermassive black hole, and the remnant of a star that exploded in a supernova over 300 years ago. Not only a milestone in the development of the LWA, the images are also a first glimpse through a new window on the cosmos. "First light" is an astronomical term for the first image produced with a telescope. It is a key milestone for any telescope because it indicates that all of the individual components are working in unison as planned. Once completed, the LWA will provide an entirely novel view of the sky, in the radio frequency range of 20-80 MHz, currently one of the most poorly explored regions of the electromagnetic spectrum in astronomy. The LWA will be able to make sensitive high-resolution images, and scan the sky rapidly for new and transient sources of radio waves, which might represent the explosion of distant, massive stars, the emissions from planets outside of our own solar system or even previously unknown objects or phenomena. "The LWA will allow us to make the sharpest images ever possible using very long wavelength radio waves. This newly opened window on the universe will help us understand the acceleration of relativistic particles in a variety of extreme astrophysical environments including from the most distant supermassive black holes. But perhaps most exciting is the promise of new source classes waiting to be discovered," says Dr. Namir Kassim, an NRL astronomer in the Remote Sensing Division and LWA Project Scientist. Dr. Tracy Clarke, of Interferometrics, Inc. in Herndon, Virginia, another astronomer on the NRL team adds, "By detecting distant clusters of galaxies the LWA may also provide new insights on the cosmological evolution of the mysterious dark matter

  20. RoboWeedSupport-Semi-Automated Unmanned Aerial System for Cost Efficient High Resolution in Sub-Millimeter Scale Acquisition of Weed Images

    OpenAIRE

    Simon L. Madsen; Mads Dyrmann; Morten S. Laursen; Rasmus N. Jørgensen

    2017-01-01

    Recent advances in the Unmanned Aerial System (UAS) safety and perception systems enable safe low altitude autonomous terrain following flights recently demonstrated by the consumer DJI Mavic PRO and Phamtom 4 Pro drones. This paper presents the first prototype system utilizing this functionality in form of semi-automated UAS based collection of crop/weed images where the embedded perception system ensures a significantly safer and faster gathering of weed images with sub-millimeter resolutio...

  1. Routing and wavelength assignment based on normalized resource and constraints for all-optical network

    Science.gov (United States)

    Joo, Seong-Soon; Nam, Hyun-Soon; Lim, Chang-Kyu

    2003-08-01

    With the rapid growth of the Optical Internet, high capacity pipes is finally destined to support end-to-end IP on the WDM optical network. Newly launched 2D MEMS optical switching module in the market supports that expectations of upcoming a transparent optical cross-connect in the network have encouraged the field applicable research on establishing real all-optical transparent network. To open up a customer-driven bandwidth services, design of the optical transport network becomes more challenging task in terms of optimal network resource usage. This paper presents a practical approach to finding a route and wavelength assignment for wavelength routed all-optical network, which has λ-plane OXC switches and wavelength converters, and supports that optical paths are randomly set up and released by dynamic wavelength provisioning to create bandwidth between end users with timescales on the order of seconds or milliseconds. We suggest three constraints to make the RWA problem become more practical one on deployment for wavelength routed all-optical network in network view: limitation on maximum hop of a route within bearable optical network impairments, limitation on minimum hops to travel before converting a wavelength, and limitation on calculation time to find all routes for connections requested at once. We design the NRCD (Normalized Resource and Constraints for All-Optical Network RWA Design) algorithm for the Tera OXC: network resource for a route is calculated by the number of internal switching paths established in each OXC nodes on the route, and is normalized by ratio of number of paths established and number of paths equipped in a node. We show that it fits for the RWA algorithm of the wavelength routed all-optical network through real experiments on the distributed objects platform.

  2. Galactic superluminal sources at different wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Iyudin, A.F

    2000-05-01

    Jet-like superluminal motion was observed in few types of the astrophysical systems. The early observations were made from radio galaxies with an active galactic nuclei (AGN) harboring accreting supermassive black hole. Similar type superluminal jets were detected in some of the hard X-ray transients with a stellar mass black hole. Galactic black-hole X-ray binaries with relativistic jets are reminiscent, though on a much smaller scale, of many of the phenomena seen in AGNs. The contemporaneous multiwavelength observations of the superluminal sources reveal the close connection between instabilities obviously originated in the accretion disk and manifested by their short timescale signature in X-rays, and the ejection of clouds of relativistic plasma observed as synchrotron emission at longer wavelengths. In this review I will attempt to summarise the observational status of the galactic relativistic jet sources and to stress out the importance of the multiwavelength observations.

  3. Progress in extended wavelength VCSEL technology

    Science.gov (United States)

    Johnson, Klein; Dummer, Matthew; Hibbs-Brenner, Mary; Hogan, William; Steidl, Charles

    2013-03-01

    Vixar has been developing VCSELs at both shorter (680nm) and longer (1850nm) wavelengths. This paper reports on advances in technology at both of these wavelengths. 680nm VCSELs based upon the AlGaAs/AlGaInP materials system were designed and fabricated for high speed operation for plastic optical fiber (POF) based links for industrial, automotive and consumer applications. High speed testing was performed in a "back-to-back" configuration over short lengths of glass fiber, over 42 meters of POF, with and without I.C. drivers and preamps, and over temperature. Performance to 90°C, 10 Gbps and over 40 meters of plastic optical fiber has been demonstrated. Reliability testing has been performed over a range of temperatures and currents. Preliminary results predict a TT1% failure of at least 240,000 hours at 40°C and an average current modulation of 4mA. In addition, the VCSELs survive 1000 hours at 85% humidity 85°C in a non-hermetic package. 1850nm InP based VCSELs are being developed for optical neurostimulation. The goals are to optimize the output power and power conversion efficiency. 7mW of DC output power has been demonstrated at room temperature, as well as a power conversion efficiency of 12%. Devices operate to 85°C. Over 70mW of pulsed power has been achieved from a 35 VCSEL array, with a pulse width of 10μsec.

  4. Quasi-objects, Cult Objects and Fashion Objects

    DEFF Research Database (Denmark)

    Andersen, Bjørn Schiermer

    2011-01-01

    This article attempts to rehabilitate the concept of fetishism and to contribute to the debate on the social role of objects as well as to fashion theory. Extrapolating from Michel Serres’ theory of the quasi-objects, I distinguish two phenomenologies possessing almost opposite characteristics....... These two phenomenologies are, so I argue, essential to quasi-object theory, yet largely ignored by Serres’ sociological interpreters. They correspond with the two different theories of fetishism found in Marx and Durkheim, respectively. In the second half of the article, I introduce the fashion object...... as a unique opportunity for studying the interchange between these two forms of fetishism and their respective phenomenologies. Finally, returning to Serres, I briefly consider the theoretical consequences of introducing the fashion object as a quasi-object....

  5. Characterization of multi-scale porous structure of fly ash/phosphate geopolymer hollow sphere structures: from submillimeter to nano-scale.

    Science.gov (United States)

    Li, Ruifeng; Wu, Gaohui; Jiang, Longtao; Sun, Dongli

    2015-01-01

    In the present work, the porous structure of fly ash/phosphate geopolymer hollow sphere structures (FPGHSS), prepared by pre-bonding and curing technology, has been characterized by multi-resolution methods from sub-millimeter to nano-scale. Micro-CT and confocal microscopy could provide the macroscopic distribution of porous structure on sub-millimeter scale, and hollow fly ashes with sphere shape and several sub-millimeter open cells with irregular shape were identified. SEM is more suitable to illustrate the distribution of micro-sized open and closed cells, and it was found that the open cells of FPGHSS were mainly formed in the interstitial porosity between fly ashes. Mercury porosimeter measurement showed that the micro-sized open cell of FPGHSS demonstrated a normal/bimodal distribution, and the peaks of pore size distribution were mainly around 100 and 10 μm. TEM observation revealed that the phosphate geopolymer was mainly composed of the porous area with nano-pores and dense areas, which were amorphous Al-O-P phase and α-Al2O3 respectively. The pore size of nano-pores demonstrated a quasi-normal distribution from about 10 to 100 nm. Therefore, detailed information of the porous structure of FPGHSS could be revealed using multiple methods. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Regulation of formation of volatile compounds of tea (Camellia sinensis) leaves by single light wavelength.

    Science.gov (United States)

    Fu, Xiumin; Chen, Yiyong; Mei, Xin; Katsuno, Tsuyoshi; Kobayashi, Eiji; Dong, Fang; Watanabe, Naoharu; Yang, Ziyin

    2015-11-16

    Regulation of plant growth and development by light wavelength has been extensively studied. Less attention has been paid to effect of light wavelength on formation of plant metabolites. The objective of this study was to investigate whether formation of volatiles in preharvest and postharvest tea (Camellia sinensis) leaves can be regulated by light wavelength. In the present study, in contrast to the natural light or dark treatment, blue light (470 nm) and red light (660 nm) significantly increased most endogenous volatiles including volatile fatty acid derivatives (VFADs), volatile phenylpropanoids/benzenoids (VPBs), and volatile terpenes (VTs) in the preharvest tea leaves. Furthermore, blue and red lights significantly up-regulated the expression levels of 9/13-lipoxygenases involved in VFADs formation, phenylalanine ammonialyase involved in VPBs formation, and terpene synthases involved in VTs formation. Single light wavelength had less remarkable influences on formation of volatiles in the postharvest leaves compared with the preharvest leaves. These results suggest that blue and red lights can be promising technology for remodeling the aroma of preharvest tea leaves. Furthermore, our study provided evidence that light wavelength can activate the expression of key genes involved in formation of plant volatiles for the first time.

  7. Automated Object Classification with ClassX

    Science.gov (United States)

    Suchkov, A. A.; Hanisch, R. J.; White, R. L.; Postman, M.; Donahue, M. E.; McGlynn, T. A.; Angelini, L.; Corcoran, M. F.; Drake, S. A.; Pence, W. D.; White, N.; Winter, E. L.; Genova, F.; Ochsenbein, F.; Fernique, P.; Derriere, S.

    ClassX is a project aimed at creating an automated system to classify X-ray sources and is envisaged as a prototype of the Virtual Observatory. As a system, ClassX creates a pipeline by integrating a network of classifiers with an engine that searches and retrieves multi-wavelength counterparts for a given target from the worldwide data storage media. At the start of the project we identified a number of issues that needed to be addressed to make the implementation of such a system possible. The most fundamental are: (a) classification methods and algorithms, (b) selection and definition of classes (object types), and (c) identification of source counterparts across multi-wavelength data. Their relevance to the project objectives will be seen in the results below as we discuss ClassX classifiers.

  8. Wavelength-stepped, actively mode-locked fiber laser based on wavelength-division-multiplexed optical delay lines

    Science.gov (United States)

    Lee, Eunjoo; Kim, Byoung Yoon

    2017-12-01

    We propose a new scheme for an actively mode-locked wavelength-swept fiber laser that produces a train of discretely wavelength-stepped pulses from a short fiber cavity. Pulses with different wavelengths are split and combined by standard wavelength division multiplexers with fiber delay lines. As a proof of concept, we demonstrate a laser using an erbium doped fiber amplifier and commercially available wavelength-division multiplexers with wavelength spacing of 0.8 nm. The results show simultaneous mode-locking at three different wavelengths. Laser output parameters in time domain, optical and radio frequency spectral domain, and the noise characteristics are presented. Suggestions for the improved design are discussed.

  9. Determining the Concentrations and Temperatures of Products in a CF_4/CHF_3/N_2 Plasma via Submillimeter Absorption Spectroscopy

    Science.gov (United States)

    Helal, Yaser H.; Neese, Christopher F.; De Lucia, Frank C.; Ewing, Paul R.; Agarwal, Ankur; Craver, Barry; Stout, Phillip J.; Armacost, Michael D.

    2017-06-01

    Plasmas used for the manufacturing of semiconductor devices are similar in pressure and temperature to those used in the laboratory for the study of astrophysical species in the submillimeter (SMM) spectral region. The methods and technology developed in the SMM for these laboratory studies are directly applicable for diagnostic measurements in the semiconductor manufacturing industry. Many of the molecular neutrals, radicals, and ions present in processing plasmas have been studied and their spectra have been cataloged or are in the literature. In this work, a continuous wave, intensity calibrated SMM absorption spectrometer was developed as a remote sensor of gas and plasma species. A major advantage of intensity calibrated rotational absorption spectroscopy is its ability to determine absolute concentrations and temperatures of plasma species from first principles without altering the plasma environment. An important part of this work was the design of the optical components which couple 500-750 GHz radiation through a commercial inductively coupled plasma chamber. The measurement of transmission spectra was simultaneously fit for background and absorption signal. The measured absorption was used to calculate absolute densities and temperatures of polar species. Measurements for CHF_3, CF_2, FCN, HCN, and CN made in a CF_4/CHF_3/N_2 plasma will be presented. Temperature equilibrium among species will be shown and the common temperature is leveraged to obtain accurate density measurements for simultaneously observed species. The densities and temperatures of plasma species are studied as a function of plasma parameters, including flow rate, pressure, and discharge power.

  10. Fibrosis and Atrial Fibrillation: Computerized and Optical Mapping; A View into the Human Atria at Submillimeter Resolution.

    Science.gov (United States)

    Hansen, Brian J; Zhao, Jichao; Fedorov, Vadim V

    2017-06-01

    Recent studies strongly suggest that the majority of atrial fibrillation (AF) patients with diagnosed or subclinical cardiac diseases have established or even pre-existing fibrotic structural remodeling, which may lead to conduction abnormalities and reentrant activity that sustain AF. As conventional treatments fail to treat AF in far too many cases, an urgent need exists to identify specific structural arrhythmogenic fibrosis patterns, which may maintain AF, in order to identify effective ablation targets for AF treatment. However, the existing challenge is to define what exact structural remodeling within the complex 3D human atrial wall is arrhythmogenic, as well as linking arrhythmogenic fibrosis to an underlying mechanism of AF maintenance in the clinical setting. This review is focused on the role of 3D fibrosis architecture in the mechanisms of AF maintenance revealed by submillimeter, high-resolution ex-vivo imaging modalities directly of human atria, as well as from in-silico 3D computational techniques that can be able to overcome in-vivo clinical limitations. The systematic integration of functional and structural imaging ex-vivo may inform the necessary integration of electrode and structural mapping in-vivo. A holistic view of AF driver mechanisms may begin to identify the defining characteristics or "fingerprints" of reentrant AF drivers, such as 3D fibrotic architecture, in order to design optimal patient-specific ablation strategies.

  11. Submillimeter wave GaAs Schottky diode application based study and optimization for 0.1-1.5 THz

    Science.gov (United States)

    Jenabi, Sarvenaz; Malekabadi, Ali; Deslandes, Dominic; Boone, Francois; Charlebois, Serge A.

    2017-08-01

    In this paper, a design and optimization method for submillimeter-wave Schottky diode is proposed. Parasitic capacitance is significantly reduced to under 20% of the total capacitance of the diode. The parasitic capacitance value is measured to be 0.6 fF for 1 μm anode radius which increased the cut-off frequency to 1.5 THz. A corresponding microfabrication process that provides higher degrees of freedom for the anode diameter, air-bridge dimensions and distance to the substrate is introduced and implemented. The DC and RF measurements are provided and compared with the simulations. In order to provide a better understanding of the diode behavior, the limiting factors of the cut-off frequency for different applications are studied and compared. For the mixer/multiplier mode, an improved and expanded formulation for calculation of the cut-off frequency is introduced. It is shown that the usable voltage bias range (with acceptable cut-off frequency) is limited by the exponential reduction of junction resistance, Rj , in mixer/multiplier mode.

  12. Wavelength-Dependent Extinction and Grain Sizes in "Dippers"

    Science.gov (United States)

    Sitko, Michael; Russell, Ray W.; Long, Zachary; Bayyari, Ammar; Assani, Korash; Grady, Carol; Lisse, Carey Michael; Marengo, Massimo; Wisniewski, John

    2018-01-01

    We have examined inter-night variability of K2-discovered "Dippers" that are not close to being viewed edge-on (as determined from previously-reported ALMA images) using the SpeX spectrograph on NASA's Infrared Telescope facility (IRTF). The three objects observed were EPIC 203850058, EPIC 205151387, and EPIC 204638512 ( = 2MASS J16042165-2130284). Using the ratio of the fluxes from 0.7-2.4 microns between two successive nights, we find that in at least two cases, the extinction increased toward shorter wavelengths. In the case of EPIC 204638512, we find that the properties of the dust differ from that seen in the diffuse interstellar medium and denser molecular clouds. However, the grain properties needed to explain the extinction does resemble those used to model the disks of many young stellar objects. The best fit to the data on EPIC 204638512 includes grains at least 500 microns in size, but lacks grains smaller than 0.25 microns. Since EPIC 204638512 is seen nearly face-on, it is possible the grains are entrained in an accretion flow that preferentially destroys the smallest grains. However, we have no indication of significant gas accretion onto the star in the form of emission lines observed in young low-mass stars. But the He I line at 1.083 microns was seen to change from night to night, and showed a P Cygni profile on one night, suggesting the gas might be outflowing from regions near the star.

  13. Submillimeter-resolution radiography of shielded structures with laser-accelerated electron beams

    OpenAIRE

    Vidya Ramanathan; Sudeep Banerjee; Nathan Powers; Nathaniel Cunningham; Nathan A. Chandler-Smith; Kun Zhao; Kevin Brown; Donald Umstadter; Shaun Clarke; Sara Pozzi; James Beene; Vane, C R; David Schultz

    2010-01-01

    We investigate the use of energetic electron beams for high-resolution radiography of flaws embedded in thick solid objects. A bright, monoenergetic electron beam (with energy >100  MeV) was generated by the process of laser-wakefield acceleration through the interaction of 50-TW, 30-fs laser pulses with a supersonic helium jet. The high energy, low divergence, and small source size of these beams make them ideal for high-resolution radiographic studies of cracks or voids embedded in dense ma...

  14. Multi-wavelength characterization of carbonaceous aerosol

    Science.gov (United States)

    Massabò, Dario; Caponi, Lorenzo; Chiara Bove, Maria; Piazzalunga, Andrea; Valli, Gianluigi; Vecchi, Roberta; Prati, Paolo

    2014-05-01

    Carbonaceous aerosol is a major component of the urban PM. It mainly consists of organic carbon (OC) and elemental carbon (EC) although a minor fraction of carbonate carbon could be also present. Elemental carbon is mainly found in the finer PM fractions (PM2.5 and PM1) and it is strongly light absorbing. When determined by optical methods, it is usually called black carbon (BC). The two quantities, EC and BC, even if both related to the refractory components of carbonaceous aerosols, do not exactly define the same PM component (Bond and Bergstrom, 2006; and references therein). Moreover, another fraction of light-absorbing carbon exists which is not black and it is generally called brown carbon (Andreae and Gelencsér, 2006). We introduce a simple, fully automatic, multi-wavelength and non-destructive optical system, actually a Multi-Wavelength Absorbance Analyzer, MWAA, to measure off-line the light absorption in Particulate Matter (PM) collected on filters and hence to derive the black and brown carbon content in the PM This gives the opportunity to measure in the same sample the concentration of total PM by gravimetric analysis, black and brown carbon, metals by, for instance, X Ray Fluorescence, and finally ions by Ion Chromatography. Up to 16 samples can be analyzed in sequence and in an automatic and controlled way within a few hours. The filter absorbance measured by MWAA was successfully validated both against a MAAP, Multi Angle Absorption Photometer (Petzold and Schönlinner, 2004), and the polar photometer of the University of Milan. The measurement of sample absorbance at three wavelengths gives the possibility to apportion different sources of carbonaceous PM, for instance fossil fuels and wood combustion. This can be done following the so called "aethalometer method" (Sandradewi et al., 2008;) but with some significant upgrades that will be discussed together the results of field campaigns in rural and urban sites. Andreae, M.O, and Gelencsér, A

  15. Wire grid polarizers for visible wavelengths

    Science.gov (United States)

    Johnson, Joshua Hans

    Detailed analysis of wire-grid (WG) polarizers for visible wavelengths is presented. Rigorous coupled-wave analysis (RCWA) is used to model their performance. The optimum choice of metal for the wires is identified, and the effects of different substrate indices of refraction are considered. The polarization properties are considered with changes in the physical parameters, including period, duty cycle, and wire thickness. It is shown that the performance of WG polarizers improves with increasing angle of incidence. The effect of non-square wire profiles is considered, as is the effect of adding additional dielectric layers between the wires and the substrate. The effect of metal oxide layers forming on the wires is also modeled. While most of this work concerns WG polarizers used in transmission, the performance in reflection is also discussed. Several visible-wavelength WG polarizers were fabricated at the Cornell Nanofabrication Facility (CNF) in Ithaca, NY. Electron-beam lithography was used to write the patterns for these devices, and two different methods of pattern transfer were compared. These were the lift-off method and reactive-ion etching (RIE). We found that lift-off could not produce wires thick enough for good polarization properties. RIE could produce much thicker wires with good profiles and was used for all of the experimental work presented here. Two different methods for metal film deposition, evaporation and sputtering were also compared. Films deposited by sputtering were found to have much lower indices of refraction and to not respond to etching as well. Thermally evaporated films performed much better in WG polarizers. Alternative methods for the mass-production of visible-wavelength WG polarizers are also discussed. The performance of the fabricated WG polarizers is compared to theory. When the measured physical parameters are used in RCWA to predict the performance, the measured extinction ratio is found to be much lower than the

  16. Polarization-multiplexed and phase-stepped fiber optic shearography using laser wavelength modulation

    Science.gov (United States)

    Groves, Roger M.; James, Stephen W.; Tatam, Ralph P.

    1999-08-01

    Shearography is a non-contact technique that measures deformation gradients, which can subsequently be used to evaluate out-of-plane strain components. In this paper orthogonal deformation gradients are measured quasi- simultaneously. The object under investigation is illuminated using linearly polarized light from an optical fiber. A polarization sensitive Michelson interferometer shears the speckle image from the object in orthogonal directions, for horizontally and vertically polarized light, allowing both displacement gradients to be measured independently. Laser diode injection current modulation provides a wavelength shift, which can be used to step between linear polarizations by using the birefringence of a highly-birefringent optical fiber. Wavelength modulation can also be used to phase step the interferograms produced, by using an unbalanced Michelson interferometer. If the wavelength modulation, optical fiber length and the pathlength imbalance are matched, then the polarization can be stepped between linear polarizations and the phase can be stepped by the same wavelength modulation. Images of the phase stepped correlation fringes and the wrapped phase maps illustrate the system operation.

  17. Alerting effects of short-wavelength (blue) and long-wavelength (red) lights in the afternoon.

    Science.gov (United States)

    Sahin, Levent; Figueiro, Mariana G

    2013-05-27

    Light has an acute effect on neuroendocrine responses, performance, and alertness. Most studies to date have linked the alerting effects of light to its ability to suppress melatonin, which is maximally sensitive to short-wavelength light. Recent studies, however, have shown alerting effects of white or narrowband short-wavelength lights during daytime, when melatonin levels are low. While the use of light at night to promote alertness is well understood, it is important to develop an understanding of how light impacts alertness during the daytime, especially during the post-lunch hours. The aim of the current study was to investigate how 48-minute exposures to short-wavelength (blue) light (40 lux, 18.9 microWatts/cm(2) λ(max) = 470 nanometers [nm]) or long-wavelength (red) light (40 lux, 18.9 microWatts/cm(2) λ(max) = 630 nm) close to the post-lunch dip hours affect electroencephalogram measures in participants with regular sleep schedules. Power in the alpha, alpha theta, and theta ranges was significantly lower (plight than after they remained in darkness. Exposure to blue light reduced alpha and alpha theta power compared to darkness, but these differences did not reach statistical significance (p>0.05). The present results extend those performed during the nighttime, and demonstrate that light can be used to increase alertness in the afternoon, close to the post-lunch dip hours. These results also suggest that acute melatonin suppression is not needed to elicit an alerting effect in humans. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. A stable and inexpensive wavelength reference for precise wavelength calibration of radial velocity spectrographs

    Science.gov (United States)

    Feger, Tobias; Ireland, Michael J.; Bento, Joao; Bacigalupo, Carlos

    2014-08-01

    We present a stable, inexpensive wavelength reference, based on a white-light interferometer for the use on current and future (arrays of) diffraction-limited radial velocity (RV) spectrographs. The primary aim of using an interferometer is to obtain a dense sinusoidal wavelength reference with spectral coverage between 450-650 nm. Its basic setup consists of an unbalanced fiber Mach-Zehnder interferometer (FMZI) that creates an interference pattern in the spectral domain due to superposition of phase delayed light, set by a fixed optical path-length difference (OPD). To achieve long-term stability, the interferometer is actively locked to a stable atomic line. The system operates in closed-loop using a thermo-optic modulator as the phase feedback component. We conducted stability measurements by superimposing the wavelength reference with thorium-argon (ThAr) emission lines and found the differential RMS shift to be ~5 m s-1 within 30 minute bins in an experiment lasting 5 hours.

  19. Wavelength division multiplexed local area networks

    Science.gov (United States)

    Kazovsky, L. G.; Barry, C.; Hickey, M.; Noronha, C.; Poggiolini, P.

    The advent of new services, such as multimedia communications, high-volume file transfer, high-definition image transmission, video/audio retrieval, and others, has created a need for high speed data networks. Future networks are expected to support, in an integrated fashion, services with highly diverse traffic requirements. Due to the high data rates involved, such networks will use optical fiber as the transmission medium. It has been recognized that current network topologies, employing single shared channels to provide connectivity between the nodes, are not adequate to provide these new services, thus, creating the need for multichannel networks. One way to realize multiple channels on the optical fiber is through the use of Wavelength-Division Multiplexing (WDM); this method has the additional advantage that, by employing tunable transmitters and/or receivers, the network topology can change dynamically in time. This paper focuses on WDM Networks. Following a discussion of the possible network topologies, we investigate the technological issues related to the implementation of such topologies, and describe some experimental implementations reported in the literature.

  20. Convolution kernels for multi-wavelength imaging

    Science.gov (United States)

    Boucaud, A.; Bocchio, M.; Abergel, A.; Orieux, F.; Dole, H.; Hadj-Youcef, M. A.

    2016-12-01

    Astrophysical images issued from different instruments and/or spectral bands often require to be processed together, either for fitting or comparison purposes. However each image is affected by an instrumental response, also known as point-spread function (PSF), that depends on the characteristics of the instrument as well as the wavelength and the observing strategy. Given the knowledge of the PSF in each band, a straightforward way of processing images is to homogenise them all to a target PSF using convolution kernels, so that they appear as if they had been acquired by the same instrument. We propose an algorithm that generates such PSF-matching kernels, based on Wiener filtering with a tunable regularisation parameter. This method ensures all anisotropic features in the PSFs to be taken into account. We compare our method to existing procedures using measured Herschel/PACS and SPIRE PSFs and simulated JWST/MIRI PSFs. Significant gains up to two orders of magnitude are obtained with respect to the use of kernels computed assuming Gaussian or circularised PSFs. A software to compute these kernels is available at https://github.com/aboucaud/pypher

  1. Design and analysis of VCSEL based twodimension wavelength converter.

    Science.gov (United States)

    Liu, H; Shum, P; Kao, M

    2003-07-14

    A novel two-dimensional vertical cavity surface emission laser (VCSEL) based wavelength converter is proposed. We developed a twodimensional transmission line laser model (TLLM) to analyze the proposed wavelength converter. This model takes into account Bragg reflectors by using the modified connecting matrix. Therefore, accurate and efficient modeling of the VCSEL structure is achieved. Extinction ratio of the output signal is investigated by considering input signal power, wavelength, facet reflectivity and cavity diameter.

  2. Wavelength encoding technique for particle analyses in hematology analyzer

    Science.gov (United States)

    Rongeat, Nelly; Brunel, Patrick; Gineys, Jean-Philippe; Cremien, Didier; Couderc, Vincent; Nérin, Philippe

    2011-07-01

    The aim of this study is to combine multiple excitation wavelengths in order to improve accuracy of fluorescence characterization of labeled cells. The experimental demonstration is realized with a hematology analyzer based on flow cytometry and a CW laser source emitting two visible wavelengths. A given optical encoding associated to each wavelength allows fluorescence identification coming from specific fluorochromes and avoiding the use of noisy compensation method.

  3. Zoom microscope objective using electrowetting lenses.

    Science.gov (United States)

    Li, Lei; Wang, Di; Liu, Chao; Wang, Qiong-Hua

    2016-02-08

    We report a zoom microscope objective which can achieve continuous zoom change and correct the aberrations dynamically. The objective consists of three electrowetting liquid lenses and two glass lenses. The magnification is changed by applying voltages on the three electrowetting lenses. Besides, the three electrowetting liquid lenses can play a role to correct the aberrations. A digital microscope based on the proposed objective is demonstrated. We analyzed the properties of the proposed objective. In contrast to the conventional objectives, the proposed objective can be tuned from ~7.8 × to ~13.2 × continuously. For our objective, the working distance is fixed, which means no movement parts are needed to refocus or change its magnification. Moreover, the zoom objective can be dynamically optimized for a wide range of wavelength. Using such an objective, the fabrication tolerance of the optical system is larger than that of a conventional system, which can decrease the fabrication cost. The proposed zoom microscope objective cannot only take place of the conventional objective, but also has potential application in the 3D microscopy.

  4. Wavelength techniques for digital holographic memories

    Science.gov (United States)

    Lande, David

    Holographic storage is a technique to store and retrieve information spread out in a volume, in contrast to current optical devices which store information locally on a surface. It provides for parallel page-by-page recording and readout of data instead of the usual serial, bit-by-bit, technique, and offers much higher diffraction-limited capacity. Success in the development of a competitive holographic storage device then depends on its cost, compactness and reliability. Since the first digital demonstrations, considerable effort by various groups has been spent in the development of high performance, practical holographic systems. This thesis presents several contributions toward this goal, suitable for holographic storage in lithium niobate and other applicable media. An intuitive explanation of volume holography is given, and Fourier analysis is used to derive the diffraction- limited capacity of digital storage in the form of elementary refractive index gratings. The physics of photorefractive materials, which are commonly used in holographic recording, is then presented, along with an established phenomenological model for grating formation. Following an analysis of imaging and multiplexing, a completely automated storage system implementing wavelength-multiplexed holography is described and evaluated, highlighting the feasibility of systems with fewer optical and mechanical components. The volatility of information in photorefractive media is then addressed by a demonstration of optical fixing, a technique based on two-photon recording mechanisms. Such an all-optical technique removes the need for heating elements, high voltages, or other post-processing elements currently used in non-volatile systems. Two-photon recording is also used to modulate, or apodize, the amplitude of volume gratings within the crystal bulk, providing a flexible technique to reduce cross-talk noise between stored pages and optimize the system capacity. Finally, simulations of

  5. MEASUREMENTS OF CO REDSHIFTS WITH Z-SPEC FOR LENSED SUBMILLIMETER GALAXIES DISCOVERED IN THE H-ATLAS SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Lupu, R. E.; Scott, K. S.; Aguirre, J. E. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Aretxaga, I. [Instituto Nacional de Astrofisica, Optica y Electronica, Aptdo. Postal 51 y 216, 72000 Puebla (Mexico); Auld, R.; Dariush, A. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom); Barton, E.; Cooke, J.; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Beelen, A. [Institut d' Astrophysique spatiale bat 121-Universite Paris-Sud, F-91405 Orsay Cedex (France); Bertoldi, F. [Argelander Institute for Astronomy, Bonn University, Auf dem Huegel 71, D-53121 Bonn (Germany); Bock, J. J.; Bradford, C. M. [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Bonfield, D. [Centre for Astrophysics Research, Science and Technology Research Centre, University of Hertfordshire, Herts AL10 9AB (United Kingdom); Buttiglione, S.; De Zotti, G. [INAF, Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, I-35122 Padova (Italy); Cava, A. [Instituto de Astrofisica de Canarias, C/Via Lactea s/n, E-38200 La Laguna (Spain); Clements, D. L. [Astrophysics Group, Physics Department, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Dannerbauer, H. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, DAPNIA/Service d' Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France); Dunne, L., E-mail: Roxana.E.Lupu@nasa.gov [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); and others

    2012-10-01

    We present new observations from Z-Spec, a broadband 185-305 GHz spectrometer, of five submillimeter bright lensed sources selected from the Herschel-Astrophysical Terahertz Large Area Survey science demonstration phase catalog. We construct a redshift-finding algorithm using combinations of the signal to noise of all the lines falling in the Z-Spec bandpass to determine redshifts with high confidence, even in cases where the signal to noise in individual lines is low. We measure the dust continuum in all sources and secure CO redshifts for four out of five (z {approx} 1.5-3). In one source, SDP.17, we tentatively identify two independent redshifts and a water line, confirmed at z = 2.308. Our sources have properties characteristic of dusty starburst galaxies, with magnification-corrected star formation rates of 10{sup 2-3} M{sub Sun} yr{sup -1}. Lower limits for the dust masses ({approx} a few 10{sup 8} M{sub Sun }) and spatial extents ({approx}1 kpc equivalent radius) are derived from the continuum spectral energy distributions, corresponding to dust temperatures between 54 and 69 K. In the local thermodynamic equilibrium (LTE) approximation, we derive relatively low CO excitation temperatures ({approx}< 100 K) and optical depths ({tau} {approx}< 1). Performing a non-LTE excitation analysis using RADEX, we find that the CO lines measured by Z-Spec (from J = 4 {yields} 3 to 10 {yields} 9, depending on the galaxy) localize the best solutions to either a high-temperature/low-density region or a low/temperature/high-density region near the LTE solution, with the optical depth varying accordingly. Observations of additional CO lines, CO(1-0) in particular, are needed to constrain the non-LTE models.

  6. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    Science.gov (United States)

    Leem, Hyun Tae; Choi, Yong; Kim, Kyu Bom; Lee, Sangwon; Yamamoto, Seiichi; Yeom, Jung-Yeol

    2017-02-01

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO4 reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm2 and the size of each LGSO scintillator element was 0.7×0.7×6 mm3. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400-600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  7. Active bacteriophage biocontrol and therapy on sub-millimeter scales towards removal of unwanted bacteria from foods and microbiomes

    Directory of Open Access Journals (Sweden)

    Stephen T. Abedon

    2017-08-01

    Full Text Available Bacteriophages can be used as antibacterial agents as a form of biological control, e.g., such as phage therapy. With active treatment, phages must “actively” produce new virions, in situ, to attain “inundative” densities, i.e., sufficient titers to eradicate bacteria over reasonable timeframes. Passive treatment, by contrast, can be accomplished using phages that are bactericidal but incapable of generating new phage virions in situ during their interaction with target bacteria. These ideas of active versus passive treatment come from theoretical considerations of phage therapy pharmacology, particularly as developed in terms of phage application to well-mixed cultures consisting of physically unassociated bacteria. Here I extend these concepts to bacteria which instead are physically associated. These are bacteria as found making up cellular arrangements or bacterial microcolonies—collectively, clonal bacterial “clumps”. I consider circumstances where active phage replication would be required to effect desired levels of bacterial clearance, but populations of bacteria nevertheless are insufficiently prevalent to support phage replication to bacteria-inundative densities across environments. Clumped bacteria, however, may still support active treatment at more local, i.e., sub-millimeter, within-clump spatial scales, and potential consequences of this are explored mathematically. Application is to the post-harvest biocontrol of foodborne pathogens, and potentially also to precise microbiome editing. Adequate infection performance by phages in terms of timely burst sizes, that is, other than just adsorption rates and bactericidal activity, thus could be important for treatment effectiveness even if bacterial densities overall are insufficient to support active treatment across environments. Poor phage replication during treatment of even low bacterial numbers, such as given food refrigeration during treatment, consequently could

  8. ALMACAL I: First Dual-band Number Counts from a Deep and Wide ALMA Submillimeter Survey, Free from Cosmic Variance

    Science.gov (United States)

    Oteo, I.; Zwaan, M. A.; Ivison, R. J.; Smail, I.; Biggs, A. D.

    2016-05-01

    We have exploited ALMA calibration observations to carry out a novel, wide, and deep submillimeter (submm) survey, almacal. These calibration data comprise a large number of observations of calibrator fields in a variety of frequency bands and array configurations. By gathering together data acquired during multiple visits to many ALMA calibrators, it is possible to reach noise levels which allow the detection of faint, dusty, star-forming galaxies (DSFGs) over a significant area. In this paper, we outline our survey strategy and report the first results. We have analyzed data for 69 calibrators, reaching depths of ˜25 μJy beam-1 at sub-arcsec resolution. Adopting a conservative approach based on ≥5σ detections, we have found 8 and 11 DSFGs in ALMA bands 6 and 7, respectively, with flux densities S 1.2 mm ≥ 0.2 mJy. The faintest galaxies would have been missed by even the deepest Herschel surveys. Our cumulative number counts have been determined independently at 870 μm and 1.2 mm from a sparse sampling of the astronomical sky, and are thus relatively free of cosmic variance. The counts are lower than reported previously by a factor of at least 2×. Future analyses will yield large, secure samples of DSFGs with redshifts determined via the detection of submm spectral lines. Uniquely, our strategy then allows for morphological studies of very faint DSFGs—representative of more normal star-forming galaxies than conventional submm galaxies—in fields where self-calibration is feasible, yielding milliarcsecond spatial resolution.

  9. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    Energy Technology Data Exchange (ETDEWEB)

    Leem, Hyun Tae [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Choi, Yong, E-mail: ychoi@sogang.ac.kr [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Kim, Kyu Bom; Lee, Sangwon [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Yamamoto, Seiichi [Department of Medical Technology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Yeom, Jung-Yeol, E-mail: jungyeol@korea.ac.kr [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of)

    2017-02-21

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO{sub 4} reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm{sup 2} and the size of each LGSO scintillator element was 0.7×0.7×6 mm{sup 3}. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400–600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  10. Video-rate computational super-resolution and integral imaging at longwave-infrared wavelengths

    OpenAIRE

    Preciado, Miguel A.; Carles, Guillem; Harvey, Andrew R.

    2017-01-01

    We report the first computational super-resolved, multi-camera integral imaging at long-wave infrared (LWIR) wavelengths. A synchronized array of FLIR Lepton cameras was assembled, and computational super-resolution and integral-imaging reconstruction employed to generate video with light-field imaging capabilities, such as 3D imaging and recognition of partially obscured objects, while also providing a four-fold increase in effective pixel count. This approach to high-resolution imaging enab...

  11. Ultra-broadband wavelength-swept Tm-doped fiber laser using wavelength-combined gain stages.

    Science.gov (United States)

    Tokurakawa, M; Daniel, J M O; Chenug, C S; Liang, H; Clarkson, W A

    2015-01-12

    A wavelength-swept thulium-doped fiber laser system employing two parallel cavities with two different fiber gain stages is reported. The fiber gain stages were tailored to provide emission in complementary bands with external wavelength-dependent feedback cavities sharing a common rotating polygon mirror for wavelength scanning. The wavelength-swept laser outputs from the fiber gain elements were spectrally combined by means of a dichroic mirror and yielded over 500 mW of output with a scanning range from ~1740 nm to ~2070 nm for a scanning frequency of ~340 Hz.

  12. A Multiwavelength Study of the Intracluster Medium and the Characterization of the Multiwavelength Sub/millimeter Inductance Camera

    Science.gov (United States)

    Siegel, Seth Robert

    The first part of this thesis combines Bolocam observations of the thermal Sunyaev-Zel'dovich (SZ) effect at 140 GHz with X-ray observations from Chandra, strong lensing data from the Hubble Space Telescope (HST), and weak lensing data from HST and Subaru to constrain parametric models for the distribution of dark and baryonic matter in a sample of six massive, dynamically relaxed galaxy clusters. For five of the six clusters, the full multiwavelength dataset is well described by a relatively simple model that assumes spherical symmetry, hydrostatic equilibrium, and entirely thermal pressure support. The multiwavelength analysis yields considerably better constraints on the total mass and concentration compared to analysis of any one dataset individually. The subsample of five galaxy clusters is used to place an upper limit on the fraction of pressure support in the intracluster medium (ICM) due to nonthermal processes, such as turbulent and bulk flow of the gas. We constrain the nonthermal pressure fraction at r500c to be less than 0.11 at 95% confidence, where r500c refers to radius at which the average enclosed density is 500 times the critical density of the Universe. This is in tension with state-of-the-art hydrodynamical simulations, which predict a nonthermal pressure fraction of approximately 0.25 at r500c for the clusters in this sample. The second part of this thesis focuses on the characterization of the Multiwavelength Sub/millimeter Inductance Camera (MUSIC), a photometric imaging camera that was commissioned at the Caltech Submillimeter Observatory (CSO) in 2012. MUSIC is designed to have a 14 arcminute, diffraction-limited field of view populated with 576 spatial pixels that are simultaneously sensitive to four bands at 150, 220, 290, and 350 GHz. It is well-suited for studies of dusty star forming galaxies, galaxy clusters via the SZ Effect, and galactic star formation. MUSIC employs a number of novel detector technologies: broadband phased

  13. Quantification of nonlinear elasticity for the evaluation of submillimeter crack length in cortical bone.

    Science.gov (United States)

    Haupert, Sylvain; Guérard, Sandra; Mitton, David; Peyrin, Françoise; Laugier, Pascal

    2015-08-01

    The objective of this study was to investigate the sensitivity of the nonlinear elastic properties of cortical bone to the presence of a single submillimetric crack. Nonlinear elasticity was measured by nonlinear resonant ultrasound spectroscopy (NRUS) in 14 human cortical bone specimens. The specimens were parallelepiped beams (50×2×2 mm(3)). A central notch of 500 µm was made to control crack initiation and propagation during four-point bending. The nonlinear hysteretic elastic and dissipative parameters αf and αQ, and Young׳s modulus Eus were measured in dry condition for undamaged (control) specimens and in dry and wet conditions for damaged specimens. The length of the crack was assessed using synchrotron radiation micro-computed tomography (SR-μCT) with a voxel size of 1.4 μm. The initial values of αf, measured on the intact specimens, were remarkably similar for all the specimens (αf =-5.5±1.5). After crack propagation, the nonlinear elastic coefficient αf increased significantly (p<0.006), with values ranging from -4.0 to -296.7. Conversely, no significant variation was observed for αQ and Eus. A more pronounced nonlinear elastic behavior was observed in hydrated specimens compared to dry specimens (p<0.001) after propagation of a single submillimetric crack. The nonlinear elastic parameter αf was found to be significantly correlated to the crack length both in dry (R=0.79, p<0.01) and wet (R=0.84, p<0.005) conditions. Altogether these results show that nonlinear elasticity assessed by NRUS is sensitive to a single submillimetric crack induced mechanically and suggest that the humidity must be strictly controlled during measurements. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. The millimeter and sub-millimeter rotational spectrum of triple 13C-substituted ethyl cyanide

    Science.gov (United States)

    Pienkina, A. O.; Margulès, L.; Motiyenko, R. A.; Müller, H. S. P.; Guillemin, J.-C.

    2017-05-01

    Context. A recently published astronomical detection of all three doubly 13C-substituted ethyl cyanides toward Sgr B2(N2) motivated us to investigate triple 13C isotopic species that are expected to be also present in the ISM. Aims: We aim to present an experimental study of the rotational spectrum of triple 13C-substituted ethyl cyanide, 13CH313CH213CN, in the frequency range 150-990 GHz. We want to use the determined spectroscopic parameters for searching for 13CH313CH213CN in ALMA data. The main objective of this work is to provide accurate frequency predictions to search for this molecule in the Galactic center source Sagittarius B2(N) and to facilitate its detection in space. Methods: The laboratory rotational spectrum of 13CH313CH213CN has been recorded with the Lille's fast DDS solid-state spectrometer between 150 GHz and 990 GHz. Results: More than 4000 rotational transitions were identified in the laboratory. The quantum numbers reach J = 115 and Ka = 39. Watson's Hamiltonian in the A and S reductions were used to analyze the spectra. Accurate spectroscopic parameters were determined. The rotational spectra of the 13C containing species CH3CH2CN have been assigned, thus allowing the determination of the rotational and centrifugal distortion constants Full Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/601/A2

  15. Per Object statistical analysis

    DEFF Research Database (Denmark)

    2008-01-01

    This RS code is to do Object-by-Object analysis of each Object's sub-objects, e.g. statistical analysis of an object's individual image data pixels. Statistics, such as percentiles (so-called "quartiles") are derived by the process, but the return of that can only be a Scene Variable, not an Object...... an analysis of the values of the object's pixels in MS-Excel. The shell of the proceedure could also be used for purposes other than just the derivation of Object - Sub-object statistics, e.g. rule-based assigment processes....... Variable. This procedure was developed in order to be able to export objects as ESRI shape data with the 90-percentile of the Hue of each object's pixels as an item in the shape attribute table. This procedure uses a sub-level single pixel chessboard segmentation, loops for each of the objects...

  16. Natural Language Object Retrieval

    OpenAIRE

    Hu, Ronghang; Xu, Huazhe; Rohrbach, Marcus; Feng, Jiashi; Saenko, Kate; Darrell, Trevor

    2015-01-01

    In this paper, we address the task of natural language object retrieval, to localize a target object within a given image based on a natural language query of the object. Natural language object retrieval differs from text-based image retrieval task as it involves spatial information about objects within the scene and global scene context. To address this issue, we propose a novel Spatial Context Recurrent ConvNet (SCRC) model as scoring function on candidate boxes for object retrieval, integ...

  17. A Multi-wavelength Ozone Lidar for the EASOE Experiment

    Science.gov (United States)

    Godin, S.; Ancellet, G.; David, C.; Porteneuve, J.; Leroy, C.; Mitev, V.; Emery, Y.; Flesia, C.; Rizi, V.; Visconti, G.

    1992-01-01

    The study of the ozone layer during winter and springtime in high latitude regions is a major issue in atmospheric research. For a better understanding of these problems, an important experimental campaign called EASOE (European Arctic Stratospheric Ozone Experiment) was organized by the European Community during the winter 1991-1992. Its main objective was to establish a budget of the ozone destruction processes on the whole northern hemisphere. This implied the simultaneous operation of different types of instruments located in both high and mid-latitude regions in order to study the destruction processes as well as the evolution of the ozone layer during the period of the campaign. A description will be given here of a mobile ozone lidar instrument specially designed for operation during the EASOE campaign. This system, which performs ozone measurements in the 5 to 40 km altitude range was located in Sodankyla, Finland as part of the ELSA experiment which also includes operation of another multi-wavelength lidar designed for polar stratospheric cloud measurements.

  18. Wavelength-Division Demultiplexing Using Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Niemi, Tapio; Frandsen, Lars Hagedorn; Hede, Kristian Knak

    2005-01-01

    We demonstrate a new device concept for wavelength division demultiplexing based on planar photonic crystal waveguides. The filtering of wavelength channels is realized by shifting the cutoff frequency of the fundamental photonic bandgap mode in consecutive sections of the waveguide. The shift is...

  19. Filamentation of ultrashort laser pulses of different wavelengths in ...

    Indian Academy of Sciences (India)

    We investigate the filaments formed by the ultrashort laser pulses with different wavelengths of 400 nm, 586 nm and 800 nm propagating in argon. Numerical results show that, when the input power or the ratio of the input power to the critical power is given, the pulse with 400 nm wavelength has the largest on-axis intensity, ...

  20. Wavelength converter placement in optical networks with dynamic traffic

    DEFF Research Database (Denmark)

    Buron, Jakob Due; Ruepp, Sarah Renée; Wessing, Henrik

    2008-01-01

    We evaluate the connection provisioning performance of GMPLS-controlled wavelength routed networks under dynamic traffic load and using three different wavelength converter placement heuristics. Results show that a simple uniform placement heuristic matches the performance of complex heuristics...... under dynamic traffic assumptions....

  1. Sub-wavelength resonances in polygonal metamaterial cylinders

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2008-01-01

    It has been shown that the sub-wavelength resonances of circular MTM cylinders also occur for polygonal MTM cylinders. This is the case for lossless and non-dispersive cylinders as well as lossy and dispersive cylinders. The sub-wavelength resonances are thus not limited to structures of canonica...

  2. Sub-wavelength metamaterial cylinders with multiple dipole resonances

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2009-01-01

    It has been shown that the sub-wavelength resonances of the individual MTM cylinders also occur for electrically small configurations combining 2 or 4 cylinders. For the 2-and 4-cylinder configurations the overall size is 1/20 and 1/12.5 of the smallest wavelength, respectively. These MTM configu...

  3. Technologies for all-optical wavelength conversion in DWDM networks

    DEFF Research Database (Denmark)

    Wolfson, David; Fjelde, Tina; Kloch, Allan

    2001-01-01

    Different techniques for all-optical wavelength conversion are reviewed and the advantages and disadvantages seen from a system perspective are highlighted. All-optical wavelength conversion will play a major role in making cost-effective network nodes in future high-speed WDM networks, where fun...

  4. Singly resonant cw OPO with simple wavelength tuning.

    Science.gov (United States)

    Vainio, Markku; Peltola, Jari; Persijn, Stefan; Harren, Frans J M; Halonen, Lauri

    2008-07-21

    A singly resonant continuous-wave optical parametric oscillator (cw OPO) is described. The OPO contains no intracavity etalon, which makes its wavelength tuning simple and straightforward, including only temperature tuning of the nonlinear crystal and wavelength tuning of the pump laser. The OPO provides watt-level output in the mid-infrared region and operates reliably without mode hops for several hours.

  5. Wavelength Preserving Optical Serial-to-Parallel Conversion

    DEFF Research Database (Denmark)

    Galili, Michael; Palushani, Evarist; Mulvad, Hans Christian Hansen

    2013-01-01

    We demonstrate optical wavelength preserving serial-to-parallel conversion. 9-of-16 OTDM channels are simultaneously mapped from a 160 Gbit/s signal to a 100 GHz WDM grid by wavelength preserving FWM idler generation, with BER<1E-9 performance....

  6. Fast fiber-optic multi-wavelength pyrometer.

    Science.gov (United States)

    Fu, Tairan; Tan, Peng; Pang, Chuanhe; Zhao, Huan; Shen, Yi

    2011-06-01

    A fast fiber-optic multi-wavelength pyrometer was developed for the ultraviolet-visible-near infrared spectra from 200 nm to 1700 nm using a CCD detector and an InGaAs detector. The pyrometer system conveniently and quickly provides the sufficient choices of multiple measurement wavelengths using optical diffraction, which avoids the use of narrow-band filters. Flexible optical fibers are used to transmit the radiation so the pyrometer can be used for temperature measurements in harsh environments. The setup and calibrations (wavelength calibration, nonlinearity calibration, and radiation response calibration) of this pyrometer system were described. Development of the multi-wavelength pyrometer involved optimization of the bandwidth and temperature discrimination of the multiple spectra data. The analysis results showed that the wavelength intervals, Δλ(CCD) = 30 nm and Δλ(InGaAs) = 50 nm, are the suitable choices as a tradeoff between the simple emissivity model assumption and the multiple signal discrimination. The temperature discrimination was also quantificationally evaluated for various wavelengths and temperatures. The measurement performance of the fiber-optic multi-wavelength pyrometer was partially verified through measurements with a high-temperature blackbody and actual hot metals. This multi-wavelength pyrometer can be used for remote high-temperature measurements. © 2011 American Institute of Physics

  7. Selection of Wavelengths for Optimum Precision in Simultaneous Spectrophotometric Determinations.

    Science.gov (United States)

    DiTusa, Michael R.; Schilt, Alfred A.

    1985-01-01

    Although many textbooks include a description of simultaneous determinations employing absorption spectrophotometry and treat the mathematics necessary for analytical quantitations, treatment of analytical wavelength selection has been mostly qualitative. Therefore, a general method for selecting wavelengths for optimum precision in simultaneous…

  8. Observing with the ISO Short-Wavelength Spectrometer

    NARCIS (Netherlands)

    deGraauw, T; Haser, LN; Beintema, DA; Roelfsema, PR; vanAgthoven, H; Barl, L; Bauer, OH; Bekenkamp, HEG; Boonstra, AJ; Boxhoorn, DR; Cote, J; deGroene, P; vanDijkhuizen, C; Evers, J; Feuchtgruber, H; Frericks, M; Genzel, R; Haerendel, G; Heras, AM; vanderHucht, KA; vanderHulst, T; Huygen, R; Jacobs, H; Jakob, G; Kamperman, T; Katterloher, RO; Kester, DJM; Kunze, D; Kussendrager, D; Lahuis, F; Lamers, HJGLM; Leech, K; vanderLei, S; vanderLinden, R; Luinge, W; Lutz, D; Melzner, F; Morris, PW; vanNguyen, D; Ploeger, G; Price, S; Salama, A; Schaeidt, SG; Sijm, N; Smoorenburg, C; Spakman, J; Spoon, H; Steinmayer, M; Stoecker, J; Valentijn, EA; Vandenbussche, B; Visser, H; Waelkens, C; Waters, LBFM; Wensink, J; Wesselius, PR; Wiezorrek, E; Wieprecht, E; Wijnbergen, JJ; Wildeman, KJ; Young, E

    1996-01-01

    The Short-Wavelength Spectrometer (SWS) is one of the four instruments on-board ESA's Infrared Space Observatory (ISO), launched on November 17, 1995. The spectrometer covers the wavelength range of 2.38 to 4.2 mu m with a spectral resolution ranging from 1000 to 2000. By inserting Fabry-Perot

  9. Planarian Phototactic Assay Reveals Differential Behavioral Responses Based on Wavelength.

    Science.gov (United States)

    Paskin, Taylor R; Jellies, John; Bacher, Jessica; Beane, Wendy S

    2014-01-01

    Planarians are free-living aquatic flatworms that possess a well-documented photophobic response to light. With a true central nervous system and simple cerebral eyes (ocelli), planarians are an emerging model for regenerative eye research. However, comparatively little is known about the physiology of their photoreception or how their behavior is affected by various wavelengths. Most phototactic studies have examined planarian behavior using white light. Here, we describe a novel planarian behavioral assay to test responses to small ranges of visible wavelengths (red, blue, green), as well as ultraviolet (UV) and infrared (IR) which have not previously been examined. Our data show that planarians display behavioral responses across a range of wavelengths. These responses occur in a hierarchy, with the shortest wavelengths (UV) causing the most intense photophobic responses while longer wavelengths produce no effect (red) or an apparent attraction (IR). In addition, our data reveals that planarian photophobia is comprised of both a general photophobic response (that drives planarians to escape the light source regardless of wavelength) and wavelength-specific responses that encompass specific behavioral reactions to individual wavelengths. Our results serve to improve the understanding of planarian phototaxis and suggest that behavioral studies performed with white light mask a complex behavioral interaction with the environment.

  10. Experimental determination of the slow-neutron wavelength distribution

    DEFF Research Database (Denmark)

    Lebech, Bente; Mikke, K.; Sledziewska-Blocka, D.

    1970-01-01

    Different experiments for determining the slow-neutron wavelength distribution in the region 227-3 meV have been carried out, and the results compared. It is concluded that the slow-neutron wave-length distribution can be determined accurately by elastic scattering on a pure incoherent or a pure...

  11. Robust and Flexible Wavelength Division Multiplexed Optical Access Networks

    DEFF Research Database (Denmark)

    Wagner, Christoph; Eiselt, Michael; Grobe, Klaus

    Future wavelength division multiplexed (WDM) access networks should be as flexible as possible. One flexibility is port wavelength-agnosticism at the optical network unit (ONU) interface, achieved via tunable laser. At the same time such systems needs to be robust against crosstalk impairments...

  12. Planarian Phototactic Assay Reveals Differential Behavioral Responses Based on Wavelength.

    Directory of Open Access Journals (Sweden)

    Taylor R Paskin

    Full Text Available Planarians are free-living aquatic flatworms that possess a well-documented photophobic response to light. With a true central nervous system and simple cerebral eyes (ocelli, planarians are an emerging model for regenerative eye research. However, comparatively little is known about the physiology of their photoreception or how their behavior is affected by various wavelengths. Most phototactic studies have examined planarian behavior using white light. Here, we describe a novel planarian behavioral assay to test responses to small ranges of visible wavelengths (red, blue, green, as well as ultraviolet (UV and infrared (IR which have not previously been examined. Our data show that planarians display behavioral responses across a range of wavelengths. These responses occur in a hierarchy, with the shortest wavelengths (UV causing the most intense photophobic responses while longer wavelengths produce no effect (red or an apparent attraction (IR. In addition, our data reveals that planarian photophobia is comprised of both a general photophobic response (that drives planarians to escape the light source regardless of wavelength and wavelength-specific responses that encompass specific behavioral reactions to individual wavelengths. Our results serve to improve the understanding of planarian phototaxis and suggest that behavioral studies performed with white light mask a complex behavioral interaction with the environment.

  13. [Influence of wearing long wavelength filter glasses on refractive development of children's hyperopia].

    Science.gov (United States)

    Huang, J; Yu, Z Q; Chu, R Y; Qian, Y S; Xu, Y; Wang, X Q

    2017-01-11

    Objective: To investigate the effect of wearing long wavelength filter glasses on refractive development of children's hyperopia. Methods: Case control study. Seventeen 5-7 years' old children with high hyperopia from optometry clinic of Eye and ENT Hospital Affiliated to Fudan University were enrolled in this research. The experiment design was self-control between right and left eye, 3 children were lost during two years' period of observation, all the children's hyperopic refraction were more than +6.00 D, cycloplegic by 1% atropine. All the children were required to wear long wavelength filter glasses for 6 hours after waking up, the rest of the time with the conventional glasses. Refraction, axis and red/green match point were tested before the intervention and 3, 6, 12, 18, 24 months, after the intervention. Results: After two years' intervention, hyperopia decreased, eye axis increased, the best corrected visual acuity increased both in experimental eyes and control eyes, but there were no statistically significant difference between the two groups at each time point. All children were with normal color vision, compared to the long-wavelength light, the hyperopic eyes were more sensitive to middle-wavelength light, no significant difference was found between two groups, red/green match points were 42.802±1.216 and 42.889±1.560 respectively. After wearing long wavelength filter, red/green match point were significant decreased in the experimental group in 6 months and 12 months time points (6 months: 0.995±0. 543 vs. 0.104±0.143, t=3.04, P=0.005, 12 months: 1.096±0.392 vs. 0.17±0.248, t=2.725, P=0.008). The experiment eyes were more sensitive to long-wavelength light than the control eyes. But in later time, there was no significant difference between two groups. Conclusion: Wearing long wavelength filter glasses two years has no effect on refractive development on children with high hyperopia, but it can cause short-term chromatic adaptation, making

  14. Mach-Zehnder wavelength selective switch embedded with microring resonators

    Science.gov (United States)

    Miura, Kengo; Shoji, Yuya; Mizumoto, Tetsuya

    2017-02-01

    A wavelength selective switch is proposed for optical wavelength division multiplexing network applications with very short range interconnections. The proposed device uses a Mach-Zehnder interferometer configuration incorporating wavelength selective phase shifters composed of microring resonators between their two arms. Wavelength selectivity is provided by cascaded microring resonators, which are placed in proximity so that the increase in excess loss caused by the difference in resonant wavelengths can be minimized. An on/off switching ratio >20 dB is obtainable when the drop/through transmittance ratio of the cascaded microring resonators is >22 dB and the coupling efficiency deviation from 50% is directional couplers constructing the Mach-Zehnder interferometer.

  15. Wavelength Assignment in Hybrid Quantum-Classical Networks.

    Science.gov (United States)

    Bahrani, Sima; Razavi, Mohsen; Salehi, Jawad A

    2018-02-22

    Optimal wavelength assignment in dense-wavelength-division-multiplexing (DWDM) systems that integrate both quantum and classical channels is studied. In such systems, weak quantum key distribution (QKD) signals travel alongside intense classical signals on the same fiber, where the former can be masked by the background noise induced by the latter. Here, we investigate how optimal wavelength assignment can mitigate this problem. We consider different DWDM structures and various sources of crosstalk and propose several near-optimal wavelength assignment methods that maximize the total secret key rate of the QKD channels. Our numerical results show that the optimum wavelength assignment pattern is commonly consisted of several interspersed quantum and classical bands. Using our proposed techniques, the total secret key rate of quantum channels can substantially be improved, as compared to conventional assignment methods, in the noise dominated regimes. Alternatively, we can maximize the number of QKD users supported under certain key rate constraints.

  16. Acoustofluidics 22: multi-wavelength resonators, applications and considerations.

    Science.gov (United States)

    Hawkes, Jeremy J; Radel, Stefan

    2013-02-21

    One important niche for multi-wavelength resonators is the filtration of suspensions containing very high particle concentration. For some applications, multi-wavelength ultrasound enhanced sedimentation filters are second only to the centrifuge in efficiency but, unlike the centrifuge they are easily adapted for continuous flow. Multi-wavelength resonators are also an obvious consideration when half-wavelength chambers are too small for a specific application. Unfortunately the formula, bigger = higher-throughput, does not scale linearly. Here we describe the relationships between chamber size and throughput for acoustic, electrical, flow and thermal convection actions, allowing the user to define initial parameters for their specific applications with some confidence. We start with a review of some of the many forms of multi-wavelength particle manipulation systems.

  17. Evaluation of wavelength groups for discrimination of agricultural cover types

    Science.gov (United States)

    Kumar, R.

    1978-01-01

    Multispectral scanner data in twelve spectral channels, in the wavelength range 0.46 to 11.7 microns, acquired in July, 1971, for three flightlines, were analyzed by applying automatic pattern recognition techniques. These twelve spectral channels were divided into four wavelength groups (W1, W2, W3 and W4), each consisting of three wavelength groups - with respect to their estimated probability of correct classification (Pc) - in discriminating agricultural cover types. The same analysis was also done for the data acquired in August, to investigate the effect of time on these results. The effect of deletion of each of the wavelength groups on Pc, in the subsets of one to nine channels, is given. Values of Pc for all possible combinations of wavelength groups, in the subsets of one to eleven channels, are also given.

  18. Lethal effects of short-wavelength visible light on insects

    Science.gov (United States)

    Hori, Masatoshi; Shibuya, Kazuki; Sato, Mitsunari; Saito, Yoshino

    2014-12-01

    We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light.

  19. Rapid Sintering of Silica Xerogel Ceramic Derived from Sago Waste Ash Using Sub-millimeter Wave Heating with a 300 GHz CW Gyrotron

    Science.gov (United States)

    Aripin, Haji; Mitsudo, Seitaro; Sudiana, I. Nyoman; Tani, Shinji; Sako, Katsuhide; Fujii, Yutaka; Saito, Teruo; Idehara, Toshitaka; Sabchevski, Sliven

    2011-06-01

    In this paper, we present and discuss experimental results from a microwave sintering of a silica-glass ceramic, produced from a silica xerogel extracted from a sago waste ash. As a radiation source for the microwave heating a sub-millimeter wave gyrotron (Gyrotron FU CW I) with an output frequency of 300 GHz has been used. The powders of silica xerogel have been dry pressed and then sintered at temperatures ranging from 300°C to 1500°C. The influence of the sintering temperature on the technological properties such as porosity and bulk density was studied in detail. Furthermore, X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy have been used in order to study the structure of the produced silica glass-ceramics. It has been found that the silica xerogel crystallizes at a temperature of 800°C, which is about 200°C lower than the one observed in the conventional process. The silica xerogel samples sintered by their irradiation with a sub-millimeter wave at 900°C for 18 minutes are fully crystallized into a silica glass-ceramic with a density of about 2.2 g/cm3 and cristobalite as a major crystalline phase. The results obtained in this study allow one to conclude that the microwave sintering with sub-millimeter waves is an appropriate technological process for production of silica glass-ceramics from a silica xerogel and is characterized with such advantages as shorter times of the thermal cycle, lower sintering temperatures and higher quality of the final product.

  20. Zooming in on Supernova 1987A at submillimetre wavelengths

    Science.gov (United States)

    Lakićević, M.; van Loon, J. Th.; Stanke, T.; De Breuck, C.; Patat, F.

    2012-05-01

    Context. Supernova 1987A (SN 1987A) in the neighbouring Large Magellanic Cloud offers a superb opportunity to follow the evolution of a supernova and its remnant in unprecedented detail. Recently, far-infrared (far-IR) and sub-mm emission was detected from the direction of SN 1987A, which was interpreted as due to the emission from dust, possibly freshly synthesized in the SN ejecta. Aims: To better constrain the location and hence origin of the far-IR and sub-mm emission in SN 1987A, we have attempted to resolve the object in that part of the electro-magnetic spectrum. Methods: We observed SN 1987A during July-September 2011 with the Atacama Pathfinder EXperiment (APEX), at a wavelength of 350 μm with the Submillimetre APEX BOlometer CAmera (SABOCA) and at 870 μm with the Large APEX BOlometer CAmera (LABOCA). The 350-μm image has superior angular resolution (8'') over that of the Herschel Space Observatory 350-μm image (25''). The 870-μm observation (at 20'' resolution) is a repetition of a similar observation made in 2007. Results: In both images, at 350 and 870 μm, emission is detected from SN 1987A, and the source is unresolved. The flux densities in the new (2011) measurements are consistent with those measured before with Herschel at 350 μm (in 2010) and with APEX at 870 μm (in 2007). A higher dust temperature (≈33 K) and lower dust mass might be possible than what was previously thought. Conclusions: The new measurements, at the highest angular resolution achieved so far at far-IR and sub-mm wavelengths, strengthen the constraints on the location of the emission, which is thought to be close to the site of SN 1987A and its circumstellar ring structures. These measurements set the stage for upcoming observations at even higher angular resolution with the Atacama Large Millimeter Array (ALMA). Processed data is only available via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/541/L1

  1. Short wavelengths active bichromatic pulsed pyrometer for solids and liquids designed for measurements in harsh environments

    Science.gov (United States)

    Navello, L.; Lebedinsky, J.; Offret, J. P.; Serio, B.; Davin, T.; Bailly, Y.; Hervé, P.

    2015-05-01

    Optical passive methods for temperature measurements such as thermography or optical pyrometry are very interesting because they allow a non-intrusive measurement when the emissivity is known. The knowledge of this coefficient is critical for determining the actual temperature of a surface from the thermal radiation emitted in a wavelength band. The bichromatic pulsed pyrometer allows to overcome the knowledge of this parameter provided that precautions are taken in the choice of the values of wavelengths. When the object to be measured is placed in harsh environments, such passive optical methods are greatly disturbed by the presence of an optically absorbing medium. They are also distorted when the measured objects are located in very hot environments emitting intense disturbing radiation. In this study, we present an active bichromatic radiometric method for measuring the temperature of a surface in harsh environments. The method is based on a localized excitation by a modulated laser source in the infrared range. Detecting the temperature modulation, which is correlated with the excitation, is performed using a lock-in amplifier able to extract the signal embedded in a noise up to a million times superior. Working at short wavelengths (visible range and near infrared range) offers a large dynamic range and minimizes the error due to variations in emissivity with the wavelength. This system collects the radiation emitted by the object at a distance from a few meters up to dozens of meters depending on the configuration of the optical system. Both the principle and the design of the active bichromatic optical surface thermometer are presented and discussed. To demonstrate the method, results obtained on a molten ceramic stream are presented.

  2. A multi-wavelength fiber laser based on superimposed fiber grating and chirp fiber Bragg grating for wavelength selection

    Science.gov (United States)

    Wang, Feng; Bi, Wei-hong; Fu, Xing-hu; Jiang, Peng; Wu, Yang

    2015-11-01

    In this paper, a new type of multi-wavelength fiber laser is proposed and demonstrated experimentally. Superimposed fiber grating (SIFG) and chirp fiber Bragg grating (CFBG) are used for wavelength selection. Based on gain equalization technology, by finely adjusting the stress device in the cavity, the gain and loss are equal, so as to suppress the modal competition and achieve multi-wavelength lasing at room temperature. The experimental results show that the laser can output stable multi-wavelength lasers simultaneously. The laser coupling loss is small, the structure is simple, and it is convenient for integration, so it can be widely used in dense wavelength division multiplexing (DWDM) system and optical fiber sensors.

  3. High-Resolution, Two-Wavelength Pyrometer

    Science.gov (United States)

    Bickler, Donald B.; Henry, Paul K.; Logiurato, D. Daniel

    1989-01-01

    Modified two-color pyrometer measures temperatures of objects with high spatial resolution. Image focused on hole 0.002 in. (0.05 mm) in diameter in brass sheet near end of bundle, causing image to be distributed so fibers covered by defocused radiation from target. Pinhole ensures radiation from only small part of target scene reaches detector, thus providing required spatial resolution. By spreading radiation over bundle, pinhole ensures entire active area of detectors utilized. Produces signal as quiet as conventional instruments but with only 1/64 input radiation.

  4. Wavelength- or Polarization-Selective Thermal Infrared Detectors for Multi-Color or Polarimetric Imaging Using Plasmonics and Metamaterials

    Directory of Open Access Journals (Sweden)

    Shinpei Ogawa

    2017-05-01

    Full Text Available Wavelength- or polarization-selective thermal infrared (IR detectors are promising for various novel applications such as fire detection, gas analysis, multi-color imaging, multi-channel detectors, recognition of artificial objects in a natural environment, and facial recognition. However, these functions require additional filters or polarizers, which leads to high cost and technical difficulties related to integration of many different pixels in an array format. Plasmonic metamaterial absorbers (PMAs can impart wavelength or polarization selectivity to conventional thermal IR detectors simply by controlling the surface geometry of the absorbers to produce surface plasmon resonances at designed wavelengths or polarizations. This enables integration of many different pixels in an array format without any filters or polarizers. We review our recent advances in wavelength- and polarization-selective thermal IR sensors using PMAs for multi-color or polarimetric imaging. The absorption mechanism defined by the surface structures is discussed for three types of PMAs—periodic crystals, metal-insulator-metal and mushroom-type PMAs—to demonstrate appropriate applications. Our wavelength- or polarization-selective uncooled IR sensors using various PMAs and multi-color image sensors are then described. Finally, high-performance mushroom-type PMAs are investigated. These advanced functional thermal IR detectors with wavelength or polarization selectivity will provide great benefits for a wide range of applications.

  5. Multispectral images of flowers reveal the adaptive significance of using long-wavelength-sensitive receptors for edge detection in bees.

    Science.gov (United States)

    Vasas, Vera; Hanley, Daniel; Kevan, Peter G; Chittka, Lars

    2017-04-01

    Many pollinating insects acquire their entire nutrition from visiting flowers, and they must therefore be efficient both at detecting flowers and at recognizing familiar rewarding flower types. A crucial first step in recognition is the identification of edges and the segmentation of the visual field into areas that belong together. Honeybees and bumblebees acquire visual information through three types of photoreceptors; however, they only use a single receptor type-the one sensitive to longer wavelengths-for edge detection and movement detection. Here, we show that these long-wavelength receptors (peak sensitivity at ~544 nm, i.e., green) provide the most consistent signals in response to natural objects. Using our multispectral image database of flowering plants, we found that long-wavelength receptor responses had, depending on the specific scenario, up to four times higher signal-to-noise ratios than the short- and medium-wavelength receptors. The reliability of the long-wavelength receptors emerges from an intricate interaction between flower coloration and the bee's visual system. This finding highlights the adaptive significance of bees using only long-wavelength receptors to locate flowers among leaves, before using information provided by all three receptors to distinguish the rewarding flower species through trichromatic color vision.

  6. Wavelength optimization for quantitative spectral imaging of breast tumor margins.

    Directory of Open Access Journals (Sweden)

    Justin Y Lo

    Full Text Available A wavelength selection method that combines an inverse Monte Carlo model of reflectance and a genetic algorithm for global optimization was developed for the application of spectral imaging of breast tumor margins. The selection of wavelengths impacts system design in cost, size, and accuracy of tissue quantitation. The minimum number of wavelengths required for the accurate quantitation of tissue optical properties is 8, with diminishing gains for additional wavelengths. The resulting wavelength choices for the specific probe geometry used for the breast tumor margin spectral imaging application were tested in an independent pathology-confirmed ex vivo breast tissue data set and in tissue-mimicking phantoms. In breast tissue, the optical endpoints (hemoglobin, β-carotene, and scattering that provide the contrast between normal and malignant tissue specimens are extracted with the optimized 8-wavelength set with <9% error compared to the full spectrum (450-600 nm. A multi-absorber liquid phantom study was also performed to show the improved extraction accuracy with optimization and without optimization. This technique for selecting wavelengths can be used for designing spectral imaging systems for other clinical applications.

  7. Tweaks to Turing Patterns, Wavelength Transitions in CDIMA

    Science.gov (United States)

    Gaskins, Delora; Pruc, Emily; Dolnik, Milos; Epstein, Irving

    2015-03-01

    Alan Turing predicted that stationary patterns could arise from a uniform steady state in a system through the processes of reaction and diffusion. Beyond the Turing instability, there exist spatially periodic states with different wavelengths. Pattern transitions, including those transitions to patterns of differing wavelengths are of interest in reaction-diffusion systems including ecological systems with patterned biomass prone to desertification. We study pattern transitions in the chlorine dioxide-iodine-malonic acid (CDIMA) system which is the prototypical system for the study of Turing patterns in chemical systems. Additions of selected halides (bromides and chlorides) to the system in its patterned state have led to the observation of up to a five fold increase in wavelength. With the concentration of these halides as bifurcation parameter we observe that these large wavelength patterns are bistable with the uniform steady state. We explore the pattern wavelength selection of this system. Wavelength halving and super lattice structure formation result from transitions between patterns of different wavelengths.

  8. Wavelength-Agile External-Cavity Diode Laser for DWDM

    Science.gov (United States)

    Pilgrim, Jeffrey S.; Bomse, David S.

    2006-01-01

    A prototype external-cavity diode laser (ECDL) has been developed for communication systems utilizing dense wavelength- division multiplexing (DWDM). This ECDL is an updated version of the ECDL reported in Wavelength-Agile External- Cavity Diode Laser (LEW-17090), NASA Tech Briefs, Vol. 25, No. 11 (November 2001), page 14a. To recapitulate: The wavelength-agile ECDL combines the stability of an external-cavity laser with the wavelength agility of a diode laser. Wavelength is modulated by modulating the injection current of the diode-laser gain element. The external cavity is a Littman-Metcalf resonator, in which the zeroth-order output from a diffraction grating is used as the laser output and the first-order-diffracted light is retro-reflected by a cavity feedback mirror, which establishes one end of the resonator. The other end of the resonator is the output surface of a Fabry-Perot resonator that constitutes the diode-laser gain element. Wavelength is selected by choosing the angle of the diffracted return beam, as determined by position of the feedback mirror. The present wavelength-agile ECDL is distinguished by design details that enable coverage of all 60 channels, separated by 100-GHz frequency intervals, that are specified in DWDM standards.

  9. Wavelength discrimination in the hummingbird hawkmoth Macroglossum stellatarum.

    Science.gov (United States)

    Telles, Francismeire J; Kelber, Almut; Rodríguez-Gironés, Miguel A

    2016-02-01

    Despite the strong relationship between insect vision and the spectral properties of flowers, the visual system has been studied in detail in only a few insect pollinator species. For instance, wavelength discrimination thresholds have been determined in two species only: the honeybee (Apis mellifera) and the butterfly Papilio xuthus. Here, we present the wavelength discrimination thresholds (Δλ) for the hawkmoth Macroglossum stellatarum. We compared the data with those found for the honeybee, the butterfly P. xuthus and the predictions of a colour discrimination model. After training moths to feed from a rewarded disc illuminated with a monochromatic light, we tested them in a dual-choice situation, in which they had to choose between light of the training wavelength and a novel unrewarded wavelength. To characterise the Δλ function, we decreased the difference between wavelengths in subsequent tests. We also varied the light intensity to test its effect on the discrimination capacity. In agreement with the predictions of the model, we found two expected minima of discrimination where photoreceptor sensitivities overlap, as well as a third, minor, unpredicted minimum around the peak of the blue photoreceptor. Macroglossum stellatarum is capable of discriminating between lights with a wavelength difference of 1-2 nm. These discrimination minima are similar to those found for the tetrachromatic P. xuthus, and are better than those of the honeybee. The moth is also capable of using achromatic information to discriminate between lights of long wavelengths. © 2016. Published by The Company of Biologists Ltd.

  10. THE STAR FORMATION HISTORIES OF z {approx} 2 DUST-OBSCURED GALAXIES AND SUBMILLIMETER-SELECTED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Bussmann, R. S. [Harvard-Smithsonian Center for Astrophysics, 160 Concord Avenue, Cambridge, MA 02138 (United States); Dey, Arjun; Jannuzi, B. T. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Armus, L.; Desai, V.; Soifer, B. T. [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Brown, M. J. I. [School of Physics, Monash University, Clayton, Victoria 3800 (Australia); Gonzalez, A. H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Melbourne, J., E-mail: rbussmann@cfa.harvard.edu [Division of Physics, Math and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-01-10

    The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z {approx} 2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M{sub *}) of two populations of Spitzer-selected ULIRGs that have extremely red R - [24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6 {mu}m associated with stellar emission ({sup b}ump DOGs{sup )}, while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ({sup p}ower-law DOGs{sup )}. We measure M{sub *} by applying Charlot and Bruzual stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations. Assuming a simple stellar population and a Chabrier initial mass function, we find that power-law DOGs and bump DOGs are on average a factor of 2 and 1.5 more massive than SMGs, respectively (median and inter-quartile M{sub *} values for SMGs, bump DOGs, and power-law DOGs are log(M{sub *}/M{sub Sun }) = 10.42{sup +0.42}{sub -0.36}, 10.62{sup +0.36}{sub -0.32}, and 10.71{sup +0.40}{sub -0.34}, respectively). More realistic star formation histories drawn from two competing theories for the nature of ULIRGs at z {approx} 2 (major merger versus smooth accretion) can increase these mass estimates by up to 0.5 dex. A comparison of our stellar masses with the instantaneous star formation rate (SFR) in these z {approx} 2 ULIRGs provides a preliminary indication supporting high SFRs for a given M{sub *}, a situation that arises more naturally in major mergers than in smooth accretion-powered systems.

  11. A Survey of the Routing and Wavelength Assignment Problem

    DEFF Research Database (Denmark)

    Gamst, Mette

    When transmitting data in an all-optical network, data connections must be established in such a way that two or more connections never share a wavelength on the same fi ber. The NP-hard Routing and Wavelength Assignment (RWA) problem consists of finding paths and wavelengths for a set of data co...... connections. This survey introduces the RWA and gives an overview of heuristic, metaheuristic and exact solution methods from the literature. Running times for the heuristic methods are presented and computational results are discussed....

  12. Analog optical computing by half-wavelength slabs

    Science.gov (United States)

    Zangeneh-Nejad, Farzad; Khavasi, Amin; Rejaei, Behzad

    2018-01-01

    A new approach to perform analog optical differentiation is presented using half-wavelength slabs. First, a half-wavelength dielectric slab is used to design a first order differentiator. The latter works properly for both major polarizations, in contrast to our previously design based on Brewster effect (Youssefi et al., 2016). Inspired by the proposed dielectric differentiator, and by exploiting the unique features of graphene, we further design and demonstrate a reconfigurable and highly miniaturized differentiator using a half-wavelength plasmonic graphene film. To the best of our knowledge, our proposed graphene-based differentiator is even smaller than the most compact differentiator presented so far.

  13. Free-space wavelength-multiplexed optical scanner.

    Science.gov (United States)

    Yaqoob, Z; Rizvi, A A; Riza, N A

    2001-12-10

    A wavelength-multiplexed optical scanning scheme is proposed for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength-dispersive optical element. With fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds and large- diameter apertures of several centimeters or more for subdegree angular scans. Analysis performed indicates an optimum scan range for a given diffraction order and grating period. Limitations include beam-spreading effects based on the varying scanner aperture sizes and the instantaneous information bandwidth of the data-carrying laser beam.

  14. Nonstoichiometric Laser Materials: Designer Wavelengths in Neodymium Doped Garnets

    Science.gov (United States)

    Walsh, Brian M.; Barnes, Norman P.

    2008-01-01

    The tunable nature of lasers provides for a wide range of applications. Most applications rely on finding available laser wavelengths to meet the needs of the research. This article presents the concept of compositional tuning, whereby the laser wavelength is designed by exploiting nonstoichiometry. For research where precise wavelengths are required, such as remote sensing, this is highly advantageous. A theoretical basis for the concept is presented and experimental results in spectroscopic measurements support the theoretical basis. Laser operation nicely demonstrates the validity of the concept of designer lasers.

  15. Experimental demonstration of wavelength domain rogue-free ONU based on wavelength-pairing for TDM/WDM optical access networks.

    Science.gov (United States)

    Lee, Jie Hyun; Park, Heuk; Kang, Sae-Kyoung; Lee, Joon Ki; Chung, Hwan Seok

    2015-11-30

    In this study, we propose and experimentally demonstrate a wavelength domain rogue-free ONU based on wavelength-pairing of downstream and upstream signals for time/wavelength division-multiplexed optical access networks. The wavelength-pairing tunable filter is aligned to the upstream wavelength channel by aligning it to one of the downstream wavelength channels. Wavelength-pairing is implemented with a compact and cyclic Si-AWG integrated with a Ge-PD. The pairing filter covered four 100 GHz-spaced wavelength channels. The feasibility of the wavelength domain rogue-free operation is investigated by emulating malfunction of the misaligned laser. The wavelength-pairing tunable filter based on the Si-AWG blocks the upstream signal in the non-assigned wavelength channel before data collision with other ONUs.

  16. Object reading: text recognition for object recognition

    NARCIS (Netherlands)

    Karaoglu, S.; van Gemert, J.C.; Gevers, T.

    2012-01-01

    We propose to use text recognition to aid in visual object class recognition. To this end we first propose a new algorithm for text detection in natural images. The proposed text detection is based on saliency cues and a context fusion step. The algorithm does not need any parameter tuning and can

  17. Seeing Objects as Faces Enhances Object Detection

    Directory of Open Access Journals (Sweden)

    Kohske Takahashi

    2015-09-01

    Full Text Available The face is a special visual stimulus. Both bottom-up processes for low-level facial features and top-down modulation by face expectations contribute to the advantages of face perception. However, it is hard to dissociate the top-down factors from the bottom-up processes, since facial stimuli mandatorily lead to face awareness. In the present study, using the face pareidolia phenomenon, we demonstrated that face awareness, namely seeing an object as a face, enhances object detection performance. In face pareidolia, some people see a visual stimulus, for example, three dots arranged in V shape, as a face, while others do not. This phenomenon allows us to investigate the effect of face awareness leaving the stimulus per se unchanged. Participants were asked to detect a face target or a triangle target. While target per se was identical between the two tasks, the detection sensitivity was higher when the participants recognized the target as a face. This was the case irrespective of the stimulus eccentricity or the vertical orientation of the stimulus. These results demonstrate that seeing an object as a face facilitates object detection via top-down modulation. The advantages of face perception are, therefore, at least partly, due to face awareness.

  18. Simultaneous shape and deformation measurements in a blood vessel model by two wavelength interferometry

    Science.gov (United States)

    Andrés, Nieves; Pinto, Cristina; Lobera, Julia; Palero, Virginia; Arroyo, M. Pilar

    2017-06-01

    Holographic techniques have been used to measure the shape and the radial deformation of a blood vessel model and a real sheep aorta. Measurements are obtained from several holograms recorded for different object states. For each object state, two holograms with two different wavelengths are multiplexed in the same digital recording. Thus both holograms are simultaneously recorded but the information from each of them is separately obtained. The shape analysis gives a wrapped phase map whose fringes are related to a synthetic wavelength. After a filtering and unwrapping process, the 3D shape can be obtained. The shape data for each line are fitted to a circumference in order to determine the local vessel radius and center. The deformation analysis also results in a wrapped phase map, but the fringes are related to the laser wavelength used in the corresponding hologram. After the filtering and unwrapping process, a 2D map of the deformation in an out-of-plane direction is reconstructed. The radial deformation is then calculated by using the shape information.

  19. Development of a Thermal/Optical Carbon Analyzer with Multi-Wavelength Capabilities

    Science.gov (United States)

    Sumlin, B.; Chow, J. C.; Watson, J. G.; Wang, X.; Gronstal, S.; Chen, L. W. A. A.; Trimble, D.

    2014-12-01

    A thermal/optical carbon analyzer (DRI Model 2015) equipped with a novel seven-wavelength light source (405, 445, 532, 635, 780, 808, and 980 nm) was developed to analyze chemical and optical properties of particles collected on quartz-fiber filters. Based on the DRI Model 2001 carbon analyzer at 633 nm, major modifications were made on mechanical and electrical components, flow control, and the carbon detector to adopt modern technologies, increase instrument reliability, and reduce costs and maintenance. The correlation between wavelength-dependent light attenuation and organic and elemental carbon (OC and EC, respectively) content allows estimation of the amount of brown and black carbon (BrC and BC, respectively) on filters. Continuous monitoring of the light reflected from and transmitted through the filter along with carbon evolved from the filter when heated to different temperatures under either inert or oxidizing gas environments provides insights into the optical properties of the carbon released from the filter; it also allows examination of the charring process as pyrolyzed char has been one of the major uncertainties in quantifying OC and EC. The objectives of this study are: 1) establish performance equivalency between the Model 2015 and Model 2001 DRI carbon analyzers when comparing similar laser wavelength to maintain consistency for long-term network sample analysis; and 2) analyze the multi-wavelength signal to quantify BrC and BC, and to optimize char correction. A selection of samples, including standard chemicals, rural and urban ambient filters, and emission sources from biomass burning, diesel and gasoline engine exhaust, and resuspended dust were measured by both the Model 2015 and Model 2001 analyzers. The instrument design, calibration, comparison with legacy analyzer, and interpretation of the multi-wavelengths measurement will be presented.

  20. Increase in data capacity utilising dimensions of wavelength, space, time, polarisation and multilevel modulation using a single laser

    DEFF Research Database (Denmark)

    Clausen, Anders; Hu, Hao; Ye, Feihong

    2015-01-01

    Increasing the capacity of optical networks while have the objective of lowering the total consumed energy per bit is challenging. By exploiting several dimensions, i.e. wavelength, space, time, polarisation and multilevel modulation simultaneously, a single laser can offer formidable capacity...

  1. Experimental investigation with respect to the performance of deep submillimeter-scaled textured tools in dry turning titanium alloy Ti-6Al-4V

    Science.gov (United States)

    Li, Ning; Chen, Yongjie; Kong, Dongdong; Tan, Shenglin

    2017-05-01

    Titanium alloy Ti-6Al-4V falls under the category of the most difficult to machine materials due to its inherent high strength maintained at elevated temperature and low thermal conductivity. Based on size effect, the poor machinability may be improved by surface texturing on the tools. Thus, the effect of deep submillimeter-scaled textures on the cutting performance in Ti-6Al-4V turning was investigated. To this end, three kinds of surface textures with different sizes were fabricated using femtosecond laser on rake faces of the uncoated cemented carbide (WC/Co) inserts. Then, dry cutting experiments were conducted with these textured inserts and conventional inserts under the condition of cutting speed Vc = 50m/min, depth of cut ap = 2 mm, and feed rate f = 0.3 mm/rev. The cutting performance is evaluated in terms of cutting forces, coefficient of friction at the tool-chip interface. Results obtained in this work show the feasibility of fabricating deep submillimeter-scaled textures on tool rake face to improve the machinability of Ti-6Al-4V. The parallel type of textured tool P01 demonstrates the best performance in both reducing cutting force and improving the friction properties on the rake face. This result can be explained by the reduced tool-chip contact area and the ploughing effect.

  2. Short-wavelength infrared laser activates the auditory neurons: comparing the effect of 980 vs. 810 nm wavelength.

    Science.gov (United States)

    Tian, Lan; Wang, Jingxuan; Wei, Ying; Lu, Jianren; Xu, Anting; Xia, Ming

    2017-02-01

    Research on auditory neural triggering by optical stimulus has been developed as an emerging technique to elicit the auditory neural response, which may provide an alternative method to the cochlear implants. However, most previous studies have been focused on using longer-wavelength near-infrared (>1800 nm) laser. The effect comparison of different laser wavelengths in short-wavelength infrared (SWIR) range on the auditory neural stimulation has not been previously explored. In this study, the pulsed 980- and 810-nm SWIR lasers were applied as optical stimuli to irradiate the auditory neurons in the cochlea of five deafened guinea pigs and the neural response under the two laser wavelengths was compared by recording the evoked optical auditory brainstem responses (OABRs). In addition, the effect of radiant exposure, laser pulse width, and threshold with the two laser wavelengths was further investigated and compared. The one-way analysis of variance (ANOVA) was used to analyze those data. Results showed that the OABR amplitude with the 980-nm laser is higher than the amplitude with the 810-nm laser under the same radiant exposure from 10 to 102 mJ/cm(2). And the laser stimulation of 980 nm wavelength has lower threshold radiant exposure than the 810 nm wavelength at varied pulse duration in 20-500 μs range. Moreover, the 810-nm laser has a wider optimized pulse duration range than the 980-nm laser for the auditory neural stimulation.

  3. Choosing for learning objects

    NARCIS (Netherlands)

    Schoonenboom, Judith; Emans, Bruno; Meijer, Joost

    2006-01-01

    Choosing for learning objects discusses eight educational ambitions and the possible roles of learning objects in realising these ambitions. The eight educational ambitions are: (1) Creating independent learning pathways, for example for lifelong learners; (2) Making education more flexible; (3)

  4. Long wavelength infrared radiation thermometry for non-contact temperature measurements in gas turbines

    Science.gov (United States)

    Manara, J.; Zipf, M.; Stark, T.; Arduini, M.; Ebert, H.-P.; Tutschke, A.; Hallam, A.; Hanspal, J.; Langley, M.; Hodge, D.; Hartmann, J.

    2017-01-01

    The objective of the EU project "Sensors Towards Advanced Monitoring and Control of Gas Turbine Engines (acronym STARGATE)" is the development of a suite of advanced sensors, instrumentation and related systems in order to contribute to the developing of the next generation of green and efficient gas turbine engines. One work package of the project deals with the design and development of a long wavelength infrared (LWIR) radiation thermometer for the non-contact measurement of the surface temperature of thermal barrier coatings (TBCs) during the operation of gas turbine engines. For opaque surfaces (e.g. metals or superalloys) radiation thermometers which are sensitive in the near or short wavelength infrared are used as state-of-the-art method for non-contact temperature measurements. But this is not suitable for oxide ceramic based TBCs (e.g. partially yttria stabilized zirconia) as oxide ceramics are semi-transparent in the near and short wavelength infrared spectral region. Fortunately the applied ceramic materials are non-transparent in the long wavelength infrared and additionally exhibit a high emittance in this wavelength region. Therefore, a LWIR pyrometer can be used for non-contact temperature measurements of the surfaces of TBCs as such pyrometers overcome the described limitation of existing techniques. For performing non-contact temperature measurements in gas turbines one has to know the infrared-optical properties of the applied TBCs as well as of the hot combustion gas in order to properly analyse the measurement data. For reaching a low uncertainty on the one hand the emittance of the TBC should be high (>0.9) in order to reduce reflections from the hot surrounding and on the other hand the absorbance of the hot combustion gas should be low (pyrometer and the selection of the optimal wavelength band where the detector should be sensitive. Besides determining the spectral infrared-optical properties (emittance, transmittance and absorbance) of the

  5. Do Cloaked Objects Really Scatter Less?

    Directory of Open Access Journals (Sweden)

    Francesco Monticone

    2013-10-01

    Full Text Available We discuss the global scattering response of invisibility cloaks over the entire electromagnetic spectrum, from static to very high frequencies. Based on linearity, causality, and energy conservation, we show that the total extinction and scattering, integrated over all wavelengths, of any linear, passive, causal, and nondiamagnetic cloak, necessarily increase compared to the uncloaked case. In light of this general principle, we provide a quantitative measure to compare the global performance of different cloaking techniques and we discuss solutions to minimize the global scattering signature of an object using thin, superconducting shells. Our results provide important physical insights on how invisibility cloaks operate and affect the global scattering of an object, suggesting ways to defeat countermeasures aimed at detecting cloaked objects using short impinging pulses.

  6. Speckle noise reduction in single-shot holographic two-wavelength contouring

    Science.gov (United States)

    Agour, Mostafa; Klattenhoff, Reiner; Falldorf, Claas; Bergmann, Ralf B.

    2017-05-01

    We present an experimental configuration that enables form measurement from a single-shot camera exposure. It combines two-wavelength contouring with spatial multiplexing synthetic-aperture digital holography. The synthetic-aperture in this work is formed by simultaneously illuminating the test object from two different angles. The two illumination directions and the two-wavelength contouring result in four holograms which are spatially multiplexed on a single camera target avoiding unwanted cross-interference between them by means of coherence gating. In contrast to standard holographic contouring methods, the proposed technique reduces speckle decorrelation noise and enables single shot form measurement. To demonstrate this technique, the shape of a micro cold drawing part is determined.

  7. Behavioral Objectives for English

    Science.gov (United States)

    Zoellner, Robert

    1972-01-01

    A review-critique of On Writing Behavioral Objectives for English, by John Maxwell and Anthony Lovat, in which behavioral objectives theory is dominated by a stimulus-response rather than a stimulus-response-reinforcement psychology. The reviewer questions whether behavioral objectives can be applied accurately and without distortion of meanings,…

  8. Objects in Motion

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

  9. Survivability via Control Objectives

    Energy Technology Data Exchange (ETDEWEB)

    CAMPBELL,PHILIP L.

    2000-08-11

    Control objectives open an additional front in the survivability battle. A given set of control objectives is valuable if it represents good practices, it is complete (it covers all the necessary areas), and it is auditable. CobiT and BS 7799 are two examples of control objective sets.

  10. On the Crime Object

    Science.gov (United States)

    Akutaev, Rasul M.; Magomedov, Guseyn B.

    2016-01-01

    The relevance of the research of this problem is caused by the theoretical and practical needs of a specific concept of the crime object as one of the corpus delicti signs essentially the determining and defining its object and objective side, thereby--the nature of socially dangerous act. Besides, being a facultative sign of corpus delicti, the…

  11. Attenuation of short wavelengths alters sleep and the ipRGC pupil response.

    Science.gov (United States)

    Ostrin, Lisa A; Abbott, Kaleb S; Queener, Hope M

    2017-07-01

    Exposure to increasing amounts of artificial light during the night may contribute to the high prevalence of reported sleep dysfunction. Release of the sleep hormone melatonin is mediated by the intrinsically photosensitive retinal ganglion cells (ipRGCs). This study sought to investigate whether melatonin level and sleep quality can be modulated by decreasing night-time input to the ipRGCs. Subjects (ages 17-42, n = 21) wore short wavelength-blocking glasses prior to bedtime for 2 weeks. The ipRGC-mediated post illumination pupil response was measured before and after the experimental period. Stimulation was presented with a ganzfeld stimulator, including one-second and five-seconds of long and short wavelength light, and the pupil was imaged with an infrared camera. Pupil diameter was measured before, during and for 60 s following stimulation, and the six-second and 30 s post illumination pupil response and area under the curve following light offset were determined. Subjects wore an actigraph device for objective measurements of activity, light exposure, and sleep. Saliva samples were collected to assess melatonin content. The Pittsburgh Sleep Quality Index (PSQI) was administered to assess subjective sleep quality. Subjects wore the blue-blocking glasses 3:57 ± 1:03 h each night. After the experimental period, the pupil showed a slower redilation phase, resulting in a significantly increased 30 s post illumination pupil response to one-second short wavelength light, and decreased area under the curve for one and five-second short wavelength light, when measured at the same time of day as baseline. Night time melatonin increased from 16.1 ± 7.5 pg mL-1 to 25.5 ± 10.7 pg mL-1 (P sleep duration increased 24 min, from 408.7 ± 44.9 to 431.5 ± 42.9 min (P short wavelength-blocking glasses at night increased subjectively measured sleep quality and objectively measured melatonin levels and sleep duration, presumably as a result of

  12. Semitransparent organic solar cells with organic wavelength dependent reflectors

    NARCIS (Netherlands)

    Galagan, Y.O.; Debije, M.G.; Blom, P.W.M.

    2011-01-01

    Semitransparent organic solar cells employing solution-processable organic wavelength dependent reflectors of chiral nematic (cholesteric) liquid crystals are demonstrated. The cholesteric liquid crystal (CLC) reflects only in a narrow band of the solar spectrum and remains transparent for the

  13. High power continuous-wave dual-wavelength alexandrite laser

    Science.gov (United States)

    Ghanbari, Shirin; Major, Arkady

    2017-10-01

    A high power dual-wavelength alexandrite (Cr:BeAl2O4) laser using a single plate birefringent filter (BRF) was demonstrated. Using a 6 mm thick BRF, dual-wavelength output at 745.2 nm and 756.2 nm (5.9 THz of frequency difference) with 850 mW of average output power was achieved as well as with 16.8% optical-to-optical and 24.2% slope efficiency. The tunability of dual-wavelength separation was also demonstrated by employing the 4 mm and 2 mm thick BRFs with similar output powers. To the best of our knowledge, this is the first demonstration of a dual-wavelength alexandrite laser.

  14. Influence of three laser wavelengths on human fibroblasts cell culture.

    Science.gov (United States)

    Crisan, Bogdan; Soritau, Olga; Baciut, Mihaela; Campian, Radu; Crisan, Liana; Baciut, Grigore

    2013-02-01

    Although experimental studies in vitro and vivo have been numerous, the effect of laser wavelength irradiation on human fibroblast cell culture is poorly understood. This emphasizes the need of additional cellular and molecular research into laser influence with low energy and power. The aim of this study was to assess the influence of three different laser wavelengths on the human skin fibroblasts cell culture. We wanted to evaluate if near infrared lasers had any influence in healing of wounds by stimulating mitochondrial activity of fibroblasts. The cells were irradiated using 830-, 980- and 2,940-nm laser wavelengths. The irradiated cells were incubated and their mitochondrial activity was assessed by the MTT assay at 24, 48 and 72 h. Simultaneously, an apoptosis assay was assessed on the irradiated fibroblasts. It can be concluded that laser light of the near-infrared region (830 and 980 nm) influences fibroblasts mitochondrial activity compared to the 2,940-nm wavelength which produces apoptosis.

  15. Massively sub-wavelength guiding of electromagnetic waves.

    Science.gov (United States)

    Hooper, I R; Tremain, B; Dockrey, J A; Hibbins, A P

    2014-12-16

    Recently a new form of ultra-thin flexible waveguide consisting of a conducting comb-like structure with a thickness of the order of 1/600(th) of the operating wavelength was presented. However, whilst the thickness of the guide was massively sub-wavelength, the remaining dimensions (the height and period of the comb) were much longer. In this paper we propose, and experimentally verify, that a modified guiding geometry consisting of a chain of ultra-thin conducting spirals allows guiding of electromagnetic waves with wavelengths that are many times (40+) longer than any characteristic dimension of the guide, enabling super-sub-wavelength guiding and localisation of electromagnetic energy.

  16. Sub-wavelength antenna enhanced bilayer graphene tunable photodetector

    Energy Technology Data Exchange (ETDEWEB)

    Beechem, III, Thomas Edwin; Howell, Stephen W.; Peters, David W.; Davids, Paul; Ohta, Taisuke

    2016-03-22

    The integration of bilayer graphene with an absorption enhancing sub-wavelength antenna provides an infrared photodetector capable of real-time spectral tuning without filters at nanosecond timescales.

  17. Wavelength Drift Corrector for Wind Lidar Receivers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop and demonstrate an receiver system utilizing our novel technique for tracking and compensating for laser wavelength shifts in lidar systems....

  18. Optical wavelength conversion via optomechanical coupling in a silica resonator

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Chunhua; Fiore, Victor; Kuzyk, Mark C.; Wang, Hailin [Department of Physics, University of Oregon, Eugene, OR (United States); Tian, Lin [University of California, Merced, CA (United States)

    2015-01-01

    In an optomechanical resonator, an optically active mechanical mode can couple to any of the optical resonances via radiation pressure. This unique property can enable a remarkable phenomenon: conversion of optical fields via optomechanical coupling between vastly different wavelengths. Here we expand an earlier experimental study [Science 338, 1609 (2012)] on classical wavelength conversion of coherent optical fields by coupling two optical modes to a mechanical breathing mode in a silica resonator. Heterodyne detection of the converted optical fields shows that the wavelength conversion process is coherent and bidirectional. The conversion efficiency obtained features a distinct saturation behavior that arises from optomechanical impedance matching. A measurement of the coherent mechanical excitation involved in the wavelength conversion process also provides additional insight on the underlying optomechanical interactions. (copyright 2014 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Low Wavelength Loss of Germanium Doped Silica Fibers

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Grüner-Nielsen, Lars; Rottwitt, Karsten

    2008-01-01

    Attenuation of four step-index fibers are measured with high accuracy from 190 nm to 1700 nm. The spectra are deconvolved into different contributions and the influence of the Urbach edge at transmission wavelengths is investigated....

  20. An 8-channel wavelength demultiplexer based on photonic crystal fiber

    Science.gov (United States)

    Malka, Dror

    2017-05-01

    We propose a novel 8-channel wavelength demultiplexer based on photonic crystal fiber (PCF) structures that operate at 1530nm, 1535nm, 1540nm, 1545nm, 1550nm, 1555nm, 1560nm and 1565nm wavelengths. The new design is based on replacing some air-holes zones with silicon nitride and lithium niobate materials along the PCF axis with optimization of the PCF size. The reason of using these materials is because that each wavelength has a different value of coupling length. Numerical investigations were carried out on the geometrical parameters by using a beam propagation method (BPM). Simulation results show that the proposed device can transmit 8-channel that works in the whole C-band (1530- 1565nm) with low crosstalk ((-16.88)-(-15.93) dB) and bandwidth (4.02-4.69nm). Thus, the device can be very useful in optical networking systems that work on dense wavelength division multiplexing (DWDM) technology.

  1. Radiation Effects on Fused Biconical Taper Wavelength Division Multiplexers

    Science.gov (United States)

    Gutierrez, Roman C.; Swift, Gary M.; Dubovitsky, Serge; Bartman, Randall K.; Barnes, Charles E.; Dorsky, Leonard

    1994-01-01

    The effects of radiation on fused biconical taper wavelength division multiplexers are presented. A theoretical model indicates that index changes in the fiber are primarily responsible for the degradation of these devices.

  2. Radiation effects on fused biconical taper wavelength division multiplexers

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, R.C.; Swift, G.M.; Dubovitsky, S.; Bartman, R.K.; Barnes, C.E.; Dorsky, L. (California Inst. of Technology, Pasadena, CA (United States). Jet Propulsion Lab.)

    1994-12-01

    The effects of radiation on fused biconical taper wavelength division multiplexers are presented. A theoretical model indicates that index changes in the fiber are primarily responsible for the degradation of these devices.

  3. Portable Long-Wavelength Infrared Camera for Civilian Application

    Science.gov (United States)

    Gunapala, S. D.; Krabach, T. N.; Bandara, S. V.; Liu, J. K.

    1997-01-01

    In this paper, we discuss the performance of this portable long-wavelength infrared camera in quantum efficiency, NEAT, minimum resolvable temperature differnce (MRTD), uniformity, etc. and its application in science, medicine and defense.

  4. Multi-wavelength VCSEL arrays using high-contrast gratings

    Science.gov (United States)

    Haglund, Erik; Gustavsson, Johan S.; Sorin, Wayne V.; Bengtsson, Jörgen; Fattal, David; Haglund, Àsa; Tan, Michael; Larsson, Anders

    2017-02-01

    The use of a high-contrast grating (HCG) as the top mirror in a vertical-cavity surface-emitting laser (VCSEL) allows for setting the resonance wavelength by the grating parameters in a post-epitaxial growth fabrication process. Using this technique, we demonstrate electrically driven multi-wavelength VCSEL arrays at 980 nm wavelength. The VCSELs are GaAs-based and the suspended GaAs HCGs were fabricated using electron-beam lithography, dry etching and selective removal of an InGaP sacrificial layer. The air-coupled cavity design enabled 4-channel arrays with 5 nm wavelength spacing and sub-mA threshold currents thanks to the high HCG reflectance.

  5. Wavelength Drift Corrector for Wind Lidar Receivers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a key innovation to improve wavelength-sensitive lidar measurements (such as wind velocity) using photon-counting receivers. A novel binning technique to...

  6. Metal-dielectric composites for beam splitting and far-field deep sub-wavelength resolution for visible wavelengths.

    Science.gov (United States)

    Yan, Changchun; Zhang, Dao Hua; Zhang, Yuan; Li, Dongdong; Fiddy, M A

    2010-07-05

    We report beam splitting in a metamaterial composed of a silver-alumina composite covered by a layer of chromium containing one slit. By simulating distributions of energy flow in the metamaterial for H-polarized waves, we find that the beam splitting occurs when the width of the slit is shorter than the wavelength, which is conducive to making a beam splitter in sub-wavelength photonic devices. We also find that the metamaterial possesses deep sub-wavelength resolution capabilities in the far field when there are two slits and the central silver layer is at least 36 nm in thickness, which has potential applications in superresolution imaging.

  7. Infrared hyperspectral upconversion imaging using spatial object translation

    DEFF Research Database (Denmark)

    Kehlet, Louis Martinus; Sanders, Nicolai Højer; Tidemand-Lichtenberg, Peter

    2015-01-01

    In this paper hyperspectral imaging in the mid-infrared wavelength region is realised using nonlinear frequency upconversion. The infrared light is converted to the near-infrared region for detection with a Si-based CCD camera. The object is translated in a predefined grid by motorized actuators...

  8. Wavelength stabilized multi-kW diode laser systems

    Science.gov (United States)

    Köhler, Bernd; Unger, Andreas; Kindervater, Tobias; Drovs, Simon; Wolf, Paul; Hubrich, Ralf; Beczkowiak, Anna; Auch, Stefan; Müntz, Holger; Biesenbach, Jens

    2015-03-01

    We report on wavelength stabilized high-power diode laser systems with enhanced spectral brightness by means of Volume Holographic Gratings. High-power diode laser modules typically have a relatively broad spectral width of about 3 to 6 nm. In addition the center wavelength shifts by changing the temperature and the driving current, which is obstructive for pumping applications with small absorption bandwidths. Wavelength stabilization of high-power diode laser systems is an important method to increase the efficiency of diode pumped solid-state lasers. It also enables power scaling by dense wavelength multiplexing. To ensure a wide locking range and efficient wavelength stabilization the parameters of the Volume Holographic Grating and the parameters of the diode laser bar have to be adapted carefully. Important parameters are the reflectivity of the Volume Holographic Grating, the reflectivity of the diode laser bar as well as its angular and spectral emission characteristics. In this paper we present detailed data on wavelength stabilized diode laser systems with and without fiber coupling in the spectral range from 634 nm up to 1533 nm. The maximum output power of 2.7 kW was measured for a fiber coupled system (1000 μm, NA 0.22), which was stabilized at a wavelength of 969 nm with a spectral width of only 0.6 nm (90% value). Another example is a narrow line-width diode laser stack, which was stabilized at a wavelength of 1533 nm with a spectral bandwidth below 1 nm and an output power of 835 W.

  9. All-fiber wavelength filter from successive biconical tapers.

    Science.gov (United States)

    Lacroix, S; Gonthier, F; Bures, J

    1986-10-01

    We demonstrate the cascading of biconical fiber tapers as a simple method for converting monomode optical fibers into wavelength filters with a prescribed response. As an example, we made a narrow-bandpass filter consisting of four biconical tapers of different elongations made in succession on a single fiber. The transmission peak of the spectral response of the filter is centered on an arbitrary wavelength within the monomode domain of the fiber. The half-power width is approximately 6 nm.

  10. Analysis of subsystems in wavelength-division-multiplexing networks

    OpenAIRE

    Liu, Fenghai; Jeppesen, Palle; Pedersen, Rune S.J.

    2001-01-01

    Wavelength division multiplexing (WDM) technology together with optical amplification has created a new era for optical communication. Transmission capacity is greatly increased by adding more and more wavelength channels into a single fiber, as well as by increasing the line rate of each channel. WDM not only can be used to increase transmission capacity, but also to introduce a new dimension to design and implement flexible, reliable, cost effective optical networks. Optical signals may pas...

  11. Coupling polariton quantum boxes in sub-wavelength grating microcavities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bo; Wang, Zhaorong; Deng, Hui, E-mail: dengh@umich.edu [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Brodbeck, Sebastian; Kamp, Martin; Schneider, Christian [Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg (Germany); Höfling, Sven [Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg (Germany); SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

    2015-02-02

    We report the construction of decoupled, coupled, and quasi-one dimensional polariton systems from zero dimensional polariton quantum boxes using microcavities with sub-wavelength gratings as the top mirror. By designing the tethering patterns around the suspended sub-wavelength gratings, we control the coupling between individual quantum boxes through different optical potentials. Energy levels and real-space or momentum space distributions of the confined modes were measured, which agreed well with simulations.

  12. Far-field measurements of short-wavelength surface plasmons

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Yochai; Gjonaj, Bergin; David, Asaf; Dolev, Shimon; Shterman, Doron; Bartal, Guy, E-mail: guy@ee.technion.ac.il [Department of Electrical Engineering, Technion - Israel Institute of Technology, Haifa 32000 (Israel)

    2015-03-23

    We present direct far-field measurements of short-wavelength surface plasmon polaritons (SPP) by conventional optics means. Plasmonic wavelength as short as 231 nm was observed for 532 nm illumination on a Ag−Si{sub 3}N{sub 4} platform, demonstrating the capability to characterize SPPs well below the optical diffraction limit. This is done by scaling a sub-wavelength interferometric pattern to a far-field resolvable periodicity. These subwavelength patterns are obtained by coupling light into counter-propagating SPP waves to create a standing-wave pattern of half the SPP wavelength periodicity. Such patterns are mapped by a scattering slit, tilted at an angle so as to increase the periodicity of the intensity pattern along it to more than the free-space wavelength, making it resolvable by diffraction limited optics. The simplicity of the method as well as its large dynamic range of measurable wavelengths make it an optimal technique to characterize the properties of plasmonic devices and high-index dielectric waveguides, to improve their design accuracy and enhance their functionality.

  13. Wavelength calibration of an imaging spectrometer based on Savart interferometer

    Science.gov (United States)

    Li, Qiwei; Zhang, Chunmin; Yan, Tingyu; Quan, Naicheng; Wei, Yutong; Tong, Cuncun

    2017-09-01

    The basic principle of Fourier-transform imaging spectrometer (FTIS) based on Savart interferometer is outlined. The un-identical distribution of the optical path difference which leads to the wavelength drift of each row of the interferogram is analyzed. Two typical methods for wavelength calibration of the presented system are described. The first method unifies different spectral intervals and maximum spectral frequencies of each row by a reference monochromatic light with known wavelength, and the dispersion compensation of Savart interferometer is also involved. The second approach is based on the least square fitting which builds the functional relation between recovered wavelength, row number and calibrated wavelength by concise equations. The effectiveness of the two methods is experimentally demonstrated with monochromatic lights and mixed light source across the detecting band of the system, and the results indicate that the first method has higher precision and the mean root-mean-square error of the recovered wavelengths is significantly reduced from 19.896 nm to 1.353 nm, while the second method is more convenient to implement and also has good precision of 2.709 nm.

  14. Objects, materiality and meaning

    DEFF Research Database (Denmark)

    Lenau, Torben Anker; Lindegaard, Hanne

    2008-01-01

    of the object, and the designers aim is therefore to tune both in order to achieve a desired goal. To do so the designer basically has 2 options: Alteration of the physical shape of the object and the selection of materials. Through the manipulation of shape and materials can symbolic and sensory information......The present research work investigates the relation between physical objects, their materiality, understood as the physical substances they are made from, and the communication from the objects. In product design of physical objects the communicative aspects are just as important as the function...... be written into the object. The materials are therefore carriers of communication, even though this is dependent of the cultural context and the environment which the object will be part of. However the designer has only minor influence on those....

  15. Abstract Objects of Verbs

    DEFF Research Database (Denmark)

    2014-01-01

    Verbs do often take arguments of quite different types. In an orthodox type-theoretic framework this results in an extreme polysemy of many verbs. In this article, it is shown that this unwanted consequence can be avoided when a theory of "abstract objects" is adopted according to which...... these objects represent non-objectual entities in contexts from which they are excluded by type restrictions. Thus these objects are "abstract'' in a functional rather than in an ontological sense: they function as representatives of other entities but they are otherwise quite normal objects. Three examples...... of such a representation are considered: the denotations of that-phrases are objects representing propositions, generic noun phrases denote objects standing for sorts, and infinitivals are viewed as denoting objects representing attributes, i.e., the "ordinary'' meanings of verb phrases....

  16. WDM cross-connect cascade based on all-optical wavelength converters for routing and wavelength slot interchanging using a reduced number of internal wavelengths

    DEFF Research Database (Denmark)

    Pedersen, Rune Johan Skullerud; Mikkelsen, Benny; Jørgensen, Bo Foged

    1998-01-01

    set of internal wavelengths without sacrificing cross-connecting capabilities. By inserting a partly equipped OXC with the new architecture in a 10-Gbit/s re-circulating loop setup we demonstrate the possibility of cascading up to ten OXCs. Furthermore, we investigate the regenerating effect...

  17. Compactly packaged monolithic four-wavelength VCSEL array with 100-GHz wavelength spacing for future-proof mobile fronthaul transport.

    Science.gov (United States)

    Lee, Eun-Gu; Mun, Sil-Gu; Lee, Sang Soo; Lee, Jyung Chan; Lee, Jong Hyun

    2015-01-12

    We report a cost-effective transmitter optical sub-assembly using a monolithic four-wavelength vertical-cavity surface-emitting laser (VCSEL) array with 100-GHz wavelength spacing for future-proof mobile fronthaul transport using the data rate of common public radio interface option 6. The wavelength spacing is achieved using selectively etched cavity control layers and fine current adjustment. The differences in operating current and output power for maintaining the wavelength spacing of four VCSELs are <1.4 mA and <1 dB, respectively. Stable operation performance without mode hopping is observed, and error-free transmission under direct modulation is demonstrated over a 20-km single-mode fiber without any dispersion-compensation techniques.

  18. Early object relations into new objects.

    Science.gov (United States)

    Downey, T W

    2001-01-01

    Two strands of change are suggested by this review, one maturational, the other therapeutic or developmental (Hartmann and Kris, 1945). By "maturational" I mean to suggest energies that infuse the individual from earliest life in a manner that includes object relations, but for the healthy exercise of which object relations per se need not be of central and crucial importance. Within wide limits such energies may be delayed until growth conditions prevail without significant distortion of certain of the organism's ego functions. Therapeutic change is analogous to developmental change in that both involve the crucial presence of another to release energies. In therapeutic change these are energies that have been repressed beyond the reach of developmental dynamics. In everyday development crisis and synthesis alternate in conjunction with new and emerging objects to add to the psychological structures brought to the fore by maturation. In many instances, as we see with John, over time and in a less focussed manner, developmental changes can approximate therapeutic change and visa versa. Freud-Dann in their "experiment" pursued one line, in which the equipmental delay brought on by extremely adverse living circumstances was redressed by providing an interpersonally enriching, loving, developmentally facilitating milieu. The sketches of individual children and John's subsequent story provide a perspective into what becomes the stuff of growth and what remains the stuff of neurosis. The developmental reserves and ego resilience of these children were impressive but probably not extraordinary. Usual growth ensued as soon as they were provided with the rich soil of Bulldogs Bank instead of the desert sand of the Tereszin concentration camp. However, no one can escape such adverse circumstances without having taken in the stuff of neurosis. Affects and percepts that were not assimilatable or even available to consciousness at the time remain buried in the unconscious

  19. Fiber grating sensor array interrogation with direct-wavelength readout of a wavelength-scanned fiber laser

    Science.gov (United States)

    Song, Minho

    2003-10-01

    We present a novel interrogation method to measure wavelength shifts in fiber Bragg grating sensor array. A fiber laser tuned by an intracavity FP (Fabry-Perot) filter was used to interrogate Bragg wavelength variations. To solve the linearity, stability, and accuracy problems caused by the nonlinear response of FP filter, we calculated the wavelength variation of the fiber laser using quadrature signal processing with an unbalanced M/Z (Mach-Zehnder) interferometer and time-delayed sampling technique. The phase modulated interferometric signal is sampled with time delay, generating quadrature phase-delayed signals. By applying arctangent demodulation and phase unwrapping algorithm to the signals, accurate wavelength readout is performed. The calculated wavelengths are mapped to corresponding temporal reflection peaks from the sensor array, which enables more accurate fiber grating interrogation without the problems from the FP filter"s nonlinear response. The wavelength resolution of ~ 20 pm was obtained in our experimental setup, which could have been greatly enhanced with faster phase modulation.

  20. Cultivating objects in interaction

    DEFF Research Database (Denmark)

    Hazel, Spencer

    2014-01-01

    the interactional resources which mundane everyday objects provide interactants in the multimodal design of their turns-at-talk. Although the objects which feature in the data – for example notepads, tables, computer monitors – have practical functions within the social ecology of these institutional settings......This paper demonstrates how an initial indexing of objects through gesture and talk provides a residual basis for later indexical development across a stretch of discourse. I show how participants are able to perform an initial mobilization of affordances (Hutchby, 2001) of objects in the immediate...... surround through a combination of vocal, visual and tactile means; once indexed one way, these objects are subsequently recycled in later multimodal turn design. By tracking recurrent participant orientations to particular objects made relevant in the surround, we are able to explore further...

  1. Confinement for Active Objects

    OpenAIRE

    Florian Kammuller

    2014-01-01

    In this paper, we provide a formal framework for the security of distributed active objects. Active objects com-municate asynchronously implementing method calls via futures. We base the formal framework on a security model that uses a semi-lattice to enable multi-lateral security crucial for distributed architectures. We further provide a security type system for the programming model ASPfun of functional active objects. Type safety and a confinement property are presented. ASPfun thus reali...

  2. Second-generation Micro-Spec: a medium-resolution spectrometer-on-a-chip for submillimeter astronomy

    Science.gov (United States)

    Cataldo, Giuseppe; Barrentine, Emily M.; Bulcha, Berhanu T.; Ehsan, Negar; Hess, Larry A.; Noroozian, Omid; Stevenson, Thomas R.; U-Yen, Kongpop; Wollack, Edward; Moseley, Samuel Harvey

    2018-01-01

    This work reports on the design of a second-generation Micro-Spec (µ-Spec), a direct-detection spectrometer which integrates all the components of a diffraction-grating spectrometer onto a ~10-cm2 chip by means of superconducting microstrip transmission lines on a monocrystalline silicon substrate. The second-generation µ-Spec is designed to operate with a resolving power of 512 over the 500-1000 µm (300-600 GHz) wavelength range, a band of interest for several spectroscopic applications in astrophysics and the study of the early (z > 8) Universe. High-altitude balloon missions would provide the first testbed to demonstrate the µ-Spec technology in a space-like environment and would represent an economically viable venue for multiple observation campaigns.A brief overview of each instrument subsystem will be provided. Emphasis will be given to the design of the spectrometer’s two-dimensional diffractive region, through which the light of different wavelengths is focused on the kinetic inductance detectors along the focal plane. An optical design optimized for balloon missions through an optimization process that satisfies specific requirements on spectrometer’s size, operating spectral range and optical performance is presented in terms of geometric layout, spectral purity and efficiency.

  3. Objective-C

    CERN Document Server

    DeVoe, Jiva

    2011-01-01

    A soup-to-nuts guide on the Objective-C programming language. Objective-C is the language behind Cocoa and Cocoa Touch, which is the Framework of applications written for the Macintosh, iPod touch, iPhone, and iPad platforms. Part of the Developer Reference series covering the hottest Apple topics, this book covers everything from the basics of the C language to advanced aspects of Apple development. You'll examine Objective-C and high-level subjects of frameworks, threading, networking, and much more.: Covers the basics of the C language and then quickly moves onto Objective-C and more advanc

  4. Abstract Objects of Verbs

    DEFF Research Database (Denmark)

    Robering, Klaus

    2014-01-01

    Verbs do often take arguments of quite different types. In an orthodox type-theoretic framework this results in an extreme polysemy of many verbs. In this article, it is shown that this unwanted consequence can be avoided when a theory of "abstract objects" is adopted according to which...... of such a representation are considered: the denotations of that-phrases are objects representing propositions, generic noun phrases denote objects standing for sorts, and infinitivals are viewed as denoting objects representing attributes, i.e., the "ordinary'' meanings of verb phrases....

  5. Comparing the effectiveness of 585-nm vs. 595-nm wavelength pulsed dye laser treatment of port wine stains in conjunction with cryogen spray cooling

    NARCIS (Netherlands)

    Chang, Cheng-Jen; Kelly, Kristen M.; van Gemert, Martin J. C.; Nelson, J. Stuart

    2002-01-01

    Background and Objectives: The objective of this study was to compare the efficacy and safety of cryogen spray cooled laser treatment (CSC-LT) at wavelengths of 585 nm vs. 595 nm for port wine stain (PWS) birthmarks in a large series of patients. Study Design/Materials and Methods: A retrospective

  6. What are Objects?

    Indian Academy of Sciences (India)

    Obj ect oriented development of software systems is becom- ing de-facto standard in large software projects. This article explains the motivation behind object orientation and how it promotes the use of software components. Objects as Reusable Subsystems. Can you imagine, designing afresh and fabricating every unit.

  7. Cultivating objects in interaction

    DEFF Research Database (Denmark)

    Hazel, Spencer

    2014-01-01

    is chapter explores patterns of repeated orientations to physical objects in interactants’ visuo-spatial and haptic surround. A number of examples are presented from advice-giving activities in various institutional settings, where participants-in-interaction initially draw on material objects at...

  8. Haptic object individuation

    NARCIS (Netherlands)

    Plaisier, M.A.; Bergmann Tiest, W.M.; Kappers, A.M.L.

    2010-01-01

    Item individuation, i.e., how we decide which parts belong to one object and which to another, is an important aspect of haptic perception and may be important for design of interfaces in which different buttons have to be distinguished. We daily hold several objects in our hand. Somehow, we decide

  9. Conscience and Conscientious Objections

    NARCIS (Netherlands)

    Schinkel, Anders

    2007-01-01

    In Western countries conscientious objection is usually accommodated in various ways, at least in certain areas (military conscription, medicine) and to some extent. It appears to be regarded as fundamentally different from other kinds of objection. But why? This study argues that conscientious

  10. Modelling Digital Media Objects

    DEFF Research Database (Denmark)

    Troelsgaard, Rasmus

    The goal of this thesis is to investigate two relevant issues regarding computational representation and classification of digital multi-media objects. With a special focus on music, a model for representation of objects comprising multiple heterogeneous data types is investigated. Necessary...

  11. On object-orientation

    NARCIS (Netherlands)

    Diertens, B.

    2010-01-01

    Although object-orientation has been around for several decades, its key concept abstraction has not been exploited for proper application of object-orientation in other phases of software development than the implementation phase. We mention some issues that lead to a lot of confusion and obscurity

  12. Simultanagnosia and object individuation.

    Science.gov (United States)

    Mazza, Veronica

    2017-06-06

    Simultanagnosic patients have difficulty in perceiving multiple objects when presented simultaneously. In this review article, I discuss how neuropsychological research on simultanagnosia has been inspirational for two interconnected lines of research related to the core mechanisms by which the visual system processes cluttered scenes. First, I review previous studies on enumeration tasks indicating that, despite their inability to identify multiple objects, simultanagnosic patients can enumerate up to 2-3 elements as efficiently as healthy individuals (the so-called "subitizing" phenomenon). This intriguing observation is one of the first results to support the existence of an "object individuation" mechanism that can spatially tag a limited set of objects simultaneously, and resonates with recent research on the brain dynamics of enumeration in healthy individuals. Second, I further develop the implications of the dissociation between object identification and object enumeration in simultanagnosia specifically for the distinction between object identification and individuation. The latter distinction has been the subject of recent neuroimaging research that has provided fine-grained information on the spatial as well as temporal aspects of object individuation and recognition. The lessons learned from neuropsychological research on exact enumeration in simultanagnosia can be generalized to the normal functioning of the human mind, and have provided insightful clues for cognitive neuroscience.

  13. Near Earth Objects

    DEFF Research Database (Denmark)

    Wolff, Stefan

    2006-01-01

    , Near Earth Objects: Asteroids and comets following paths that bring them near the Earth. NEOs have collided with the Earth since its formation, some causing local devastation, some causing global climate changes, yet the threat from a collision with a near Earth object has only recently been recognised...

  14. Programs as Data Objects

    DEFF Research Database (Denmark)

    This book constitutes the refereed proceedings of the Second Symposium on Programs as Data Objects, PADO 2001, held in Aarhus, Denmark, in May 2001. The 14 revised full papers presented were carefully reviewed and selected from 30 submissions. Various aspects of looking at programs as data objects...... are covered from the point of view of program analysis, program transformation, computational complexity, etc....

  15. Gamifying Video Object Segmentation.

    Science.gov (United States)

    Spampinato, Concetto; Palazzo, Simone; Giordano, Daniela

    2017-10-01

    Video object segmentation can be considered as one of the most challenging computer vision problems. Indeed, so far, no existing solution is able to effectively deal with the peculiarities of real-world videos, especially in cases of articulated motion and object occlusions; limitations that appear more evident when we compare the performance of automated methods with the human one. However, manually segmenting objects in videos is largely impractical as it requires a lot of time and concentration. To address this problem, in this paper we propose an interactive video object segmentation method, which exploits, on one hand, the capability of humans to identify correctly objects in visual scenes, and on the other hand, the collective human brainpower to solve challenging and large-scale tasks. In particular, our method relies on a game with a purpose to collect human inputs on object locations, followed by an accurate segmentation phase achieved by optimizing an energy function encoding spatial and temporal constraints between object regions as well as human-provided location priors. Performance analysis carried out on complex video benchmarks, and exploiting data provided by over 60 users, demonstrated that our method shows a better trade-off between annotation times and segmentation accuracy than interactive video annotation and automated video object segmentation approaches.

  16. Time-resolved two-wavelength contouring of adaptive fluidic PDMS-lenses

    Science.gov (United States)

    Hansel, Thomas; Grunwald, Ruediger; Steinmeyer, Günter; Griebner, Uwe; Schneider, Florian; Wallrabe, Ulrike

    2009-05-01

    We present a synthesized sub-ps dual-wavelength laser source for digital holographic interferometry with a wide reconstruction range. The developed laser source generates two spectrally separated parts within one pulse. The sub-ps pulse duration desensitizes the holographic setup to environmental impacts. A center wavelength distance of only 12 nm with a high contrast was demonstrated by spectral shaping of the 50 nm broad seed spectrum of a CPA Ti:sapphire laser system centered at 800 nm. Time-resolved two-wavelength contouring requires the simultaneous and separable recording of two holograms. In general, a single CCD-camera is applied, and the spectral separation is realized by different reference wave tilts, which requires ambitious interferometric setups. Contrary to this, we introduce two CCD-cameras for digital holographic recording, thus essentially simplifying the interferometric setup by the need of only one propagation direction of the reference wave. To separate the holograms for the simultaneous recording process, a Mach-Zehnder interferometer was extended by a polarization encoding sequence. To study our approach of time-resolved digital holographic two-wavelength contouring, an adaptive fluidic PDMS-lens with integrated piezoelectric actuator served as test object. The PDMS-lens consists of an oil-filled lens chamber and a pump actuator. If a voltage is applied to the piezoelectric bending actuator the fluid is pumped into the lens chamber which causes a curvature change of the 60-μm thick lens membrane and thus a shift of the focal length. The dynamic behavior of the PDMS-lens, driven at a frequency of 1 Hz, was investigated at a frame rate of 410 frames per second. The measured temporal change of the lens focal length between 98 and 44 mm followed the modulation of the piezoelectric voltage with a 30 V peak-to-peak amplitude. Due to the performed time-resolved two wavelength contouring, we are able to extract the optical path length differences

  17. Promising new wavelengths for multi-photon microscopy: thinking outside the Ti:Sapphire box

    Science.gov (United States)

    Norris, Greg; Amor, Rumelo; Dempster, John; Amos, William B.; McConnell, Gail

    2013-02-01

    Multi-photon excitation (MPE) imaging is dominated by the Ti:Sapphire laser as the source for excitation. However, it is limited when considering 3PE of common fluorophores and efficient 2PE of UV dyes which require wavelengths beyond the range of the Ti:Sapphire. Two ultra-short pulsed sources are presented as alternatives: a novel optical parametric oscillator (OPO) geometry (1400-1600nm) and the sum-frequency mixing of an OPO and Yb-doped fibre laser, providing a tunable output (626-635nm). For long wavelengths, we report three-photon laser scanning microscopy (3PLSM) using a bi-directional pumped optical parametric oscillator (OPO) with signal wavelength output at 1500 nm. This novel laser was used to overcome the high optical loss in the infrared spectral region observed in laser scanning microscopes and objective lenses that renders them otherwise difficult to use for imaging. To test our system, we performed 3PLSM auto-fluorescence imaging of live plant cells at 1500 nm, specifically Spirogyra, and compared performance with two-photon excitation (2PLSM) imaging using a femtosecond pulsed Ti:Sapphire laser at 780 nm. Analysis of cell viability based on cytoplasmic organelle streaming and structural changes of cells revealed that at similar peak powers, 2PLSM caused gross cell damage after 5 minutes but 3PLSM showed little or no interference with cell function after 15 minutes. The 1500 nm OPO was thus shown to be a practical laser source for live cell imaging. For short wavelengths, we report the use of an all-solid-state ultra-short pulsed source specifically for two-photon microscopy at wavelengths shorter than those of the conventional Ti:Sapphire laser. Our approach involved sumfrequency mixing of the output from the long-wavelength OPO described above with residual pump radiation to generate fs-pulsed output in the red spectral region. We demonstrated the performance of our ultra-short pulsed system using fluorescently labelled and autofluorescent tissue

  18. Ghostly Glow Reveals a Hidden Class of Long-Wavelength Radio Emitters

    Science.gov (United States)

    2008-10-01

    (Washington, DC. 08)- A team of scientists, including astronomers from the Naval Research Laboratory (NRL), have detected long wavelength radio emission from a colliding, massive galaxy cluster which, surprisingly, is not detected at the shorter wavelengths typically seen in these objects. The discovery implies that existing radio telescopes have missed a large population of these colliding objects. It also provides an important confirmation of the theoretical prediction that colliding galaxy clusters accelerate electrons and other particles to very high energies through the process of turbulent waves. The team revealed their findings in the October 16, 2008 edition of Nature. This new population of objects is most easily detected at long wavelengths. Professor Greg Taylor of the University of New Mexico and scientific director of the Long Wavelength Array (LWA) points out, "This result is just the tip of the iceberg. When an emerging suite of much more powerful low frequency telescopes, including the LWA in New Mexico, turn their views to the cosmos, the sky will 'light up' with hundreds or even thousands of colliding galaxy clusters." NRL has played a key role in promoting the development of this generation of new instruments and is currently involved with the development of the LWA. NRL radio astronomer and LWA Project Scientist Namir Kassim says "Our discovery of a previously hidden class of low frequency cluster-radio sources is particularly important since the study of galaxy clusters was a primary motivation for development of the LWA." The discovery of the emission in the galaxy cluster Abell 521 (or A521 for short) was made using the Giant Metrewave Radiotelescope (GMRT) in India, and its long wavelength nature was confirmed by the National Science Foundation's (NRAO) Very Large Array (VLA) radio telescope in New Mexico. The attached image shows the radio emission at a wavelength of 125cm in red superimposed on a blue image made from data taken by the

  19. Spitzer IRS Observations of FU Orionis Objects

    Science.gov (United States)

    Green, J. D.; Hartmann, L.; Calvet, N.; Watson, D. M.; Ibrahimov, M.; Furlan, E.; Sargent, B.; Forrest, W. J.

    2006-09-01

    We present 5-35 μm spectra, taken with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope, of five FU Orionis objects: FU Ori, V1515 Cyg, V1057 Cyg, BBW 76, and V346 Nor. All but V346 Nor reveal amorphous silicate grains in emission at 10 and 20 μm, and show water-vapor absorption bands at 5.8 and 6.8 μm and SiO or possibly methane absorption at 8 μm. These absorption features closely match these bands in model stellar photospheres-signs of the gaseous photospheres of the inner regions of these objects' accretion disks. The continuum emission at 5-8 μm is also consistent with such disks, and, for FU Orionis and BBW 76, longer wavelength emission may be fit by a model that includes moderate disk flaring. V1057 Cyg and V1515 Cyg have much more emission at longer wavelengths than the others, perhaps evidence of a substantial remnant of their natal, infalling envelopes.

  20. Choice of the laser wavelength for a herpetic keratitis treatment

    Science.gov (United States)

    Razhev, Alexander M.; Bagayev, Sergei N.; Chernikh, Valery V.; Kargapoltsev, Evgeny S.; Trunov, Alexander; Zhupikov, Andrey A.

    2002-06-01

    For the first time the effect of the UV laser radiation to human eye cornea with herpetic keratitis was experimentally investigated. In experiments the UV radiation of ArF (193 nm), KrCl (223 nm), KrF (248 nm) excimer lasers were used. Optimal laser radiation parameters for the treatment of the herpetic keratitis were determined. The immuno-biochemical investigations were carried out and the results of clinical trials are presented. The maximum ablation rate was obtained for the 248 nm radiation wavelength. The process of healing was successful but in some cases the haze on the surface of the cornea was observed. When used the 193 nm radiation wavelength the corneal surface was clear without any hazes but the epithelization process was slower than for 248 nm wavelength and in some cases the relapse was occurred. The best results for herpetic keratitis treatment have been achieved by utilizing the 223 nm radiation wavelength of the KrCl excimer laser. The use of the 223 nm radiation wavelength allows treating the herpetic keratitis with low traumatic process of ablation and provides high quality of corneal surface.

  1. Design of a wavelength frame multiplication system using acceptance diagrams

    Energy Technology Data Exchange (ETDEWEB)

    Nekrassov, D., E-mail: daniil.nekrassov@helmholtz-berlin.de; Zendler, C., E-mail: carolin.zendler@helmholtz-berlin.de; Lieutenant, K., E-mail: klaus.lieutenant@helmholtz-berlin.de

    2013-07-11

    The concept of Wavelength Frame Multiplication (WFM) was developed to extend the usable wavelength range on long pulse neutron sources for instruments using pulse shaping choppers. For some instruments, it is combined with a pulse shaping double chopper, which defines a constant wavelength resolution, and a set of frame overlap choppers that prevent spurious neutrons from reaching the detector thus avoiding systematic errors in the calculation of wavelength from time of flight. Due to its complexity, the design of such a system is challenging and there are several criteria that need to be accounted for. In this work, the design of the WFM chopper system for a potential future liquids reflectometer at the European Spallation Source (ESS) is presented, which makes use of acceptance diagrams. They prove to be a powerful tool for understanding the work principle of the system and recognizing potential problems. The authors assume that the presented study can be useful for design or upgrade of further instruments, in particular the ones planned for the ESS. -- Highlights: • Design of a wavelength frame multiplication system for a long pulse source beamline. • First application of the acceptance diagrams method to WFM systems. • Confirmation of analytical considerations by neutronic MC simulations. • Implications of this work for instrument design at the European Spallation Source.

  2. Highly efficient entanglement swapping and teleportation at telecom wavelength.

    Science.gov (United States)

    Jin, Rui-Bo; Takeoka, Masahiro; Takagi, Utako; Shimizu, Ryosuke; Sasaki, Masahide

    2015-03-20

    Entanglement swapping at telecom wavelengths is at the heart of quantum networking in optical fiber infrastructures. Although entanglement swapping has been demonstrated experimentally so far using various types of entangled photon sources both in near-infrared and telecom wavelength regions, the rate of swapping operation has been too low to be applied to practical quantum protocols, due to limited efficiency of entangled photon sources and photon detectors. Here we demonstrate drastic improvement of the efficiency at telecom wavelength by using two ultra-bright entangled photon sources and four highly efficient superconducting nanowire single photon detectors. We have attained a four-fold coincidence count rate of 108 counts per second, which is three orders higher than the previous experiments at telecom wavelengths. A raw (net) visibility in a Hong-Ou-Mandel interference between the two independent entangled sources was 73.3 ± 1.0% (85.1 ± 0.8%). We performed the teleportation and entanglement swapping, and obtained a fidelity of 76.3% in the swapping test. Our results on the coincidence count rates are comparable with the ones ever recorded in teleportation/swapping and multi-photon entanglement generation experiments at around 800 nm wavelengths. Our setup opens the way to practical implementation of device-independent quantum key distribution and its distance extension by the entanglement swapping as well as multi-photon entangled state generation in telecom band infrastructures with both space and fiber links.

  3. Sensitivity of heterointerfaces on emission wavelength of quantum cascade lasers

    Science.gov (United States)

    Wang, C. A.; Schwarz, B.; Siriani, D. F.; Connors, M. K.; Missaggia, L. J.; Calawa, D. R.; McNulty, D.; Akey, A.; Zheng, M. C.; Donnelly, J. P.; Mansuripur, T. S.; Capasso, F.

    2017-04-01

    The measured emission wavelengths of AlInAs/GaInAs/InP quantum cascade lasers (QCLs) grown by metal organic vapor phase epitaxy (MOVPE) have been reported to be 0.5-1 μm longer than the designed QCL wavelength. This work clarifies the origin of the red-shifted wavelength. It was found that AlInAs/GaInAs heterointerfaces are compositionally graded over 2.5-4.5 nm, and indium accumulates at the AlInAs-to-GaInAs interface. Thus, the as-grown QCLs are far from the ideal abrupt interfaces used in QCL modeling. When graded layers are incorporated in QCL band structure and wavefunction calculations, the emission wavelengths are red shifted. Furthermore, we demonstrate that QCLs with graded interfaces can be designed without compromising performance and show greatly improved correlation between designed and measured emission wavelength. QCLs were designed for emission between 7.5 and 8.5 μm. These structures were grown and wet-etched ridge devices were fabricated. The QCLs exhibit room temperature peak powers exceeding 900 mW and pulsed efficiencies of 8 to 10%.

  4. Lux vs. wavelength in light treatment of Seasonal Affective Disorder.

    Science.gov (United States)

    Anderson, J L; Glod, C A; Dai, J; Cao, Y; Lockley, S W

    2009-09-01

    Published dosing guidelines for treatment of Seasonal Affective Disorder (SAD) refer to photopic lux, which is not appropriate for short-wavelength light. Short wavelengths are most potent for many non-visual responses to light. If SAD therapy were similarly mediated, standards utilizing lux risk overestimating necessary dose. We investigated antidepressant responses to light using two light-emitting diode (LED) sources, each emitting substantial short-wavelength light, but <2500 lux. A randomized, double-blind trial investigated 3-week 45 min/day out-patient treatment with blue-appearing (goLITE) or blue-enriched white-appearing light in 18 moderately-depressed adults (12F, 49.1 +/- 9.5 years). Equivalent numbers of photons within the short-wavelength range were emitted, but the white source emitted twice as many photons overall and seven-fold more lux. Depression ratings (SIGH-ADS; http://www.cet.org) decrease averaged 82% (SD = 17%) from baseline (P < 0.0001) in both white- and blue-light groups. Both sources were well tolerated. Short-wavelength LED light sources may be effective in SAD treatment at fewer lux than traditional fluorescent sources.

  5. Wavelength scaling of silicon laser ablation in picosecond regime

    Science.gov (United States)

    Sikora, A.; Grojo, D.; Sentis, M.

    2017-07-01

    Single pulse laser ablation of silicon has been investigated at 343, 515, and 1030 nm using a laser pulse duration of 50 ps. In this large spectral range, ablation thresholds of silicon vary from 0.01 to 0.83 J/cm2, confirming a strong dependence on the wavelength. By solving the free-carrier density rate equation at threshold conditions, we show that band-to-band linear absorption dominates energy deposition at 343 and 515 nm, whereas at 1030 nm, the energy leading to ablation is primarily absorbed by the generated free-carriers. This allows us to determine the relevant criteria to derive a simple model predicting the wavelength dependence of the ablation threshold in this regime. We obtain an excellent agreement between experimental measurements and calculations by simply considering an averaged energy density required in the absorption depth for surface ablation and accounting for the laser-induced variations of the important thermophysical parameters. On the basis of this analysis, we discuss the optimal wavelength and fluence conditions for maximum removal rate, ablation efficiency, and accuracy. Despite the difference in mechanisms at the different wavelengths, we find that the maximal efficiency remains at around 7 times the ablation threshold fluence for all investigated wavelengths. This work provides guidelines for high-quality and efficient micromachining of silicon in the scarcely explored picosecond regime, while new picosecond sources offer numerous advantages for real throughput industrial applications.

  6. A multi-wavelength IR laser for space applications

    Science.gov (United States)

    Li, Steven X.; Yu, Anthony W.; Sun, Xiaoli; Fahey, Molly E.; Numata, Kenji; Krainak, Michael A.

    2017-05-01

    We present a laser technology development with space flight heritage to generate laser wavelengths in the near- to midinfrared (NIR to MIR) for space lidar applications. Integrating an optical parametric crystal to the LOLA (Lunar Orbiter Laser Altimeter) laser transmitter design affords selective laser wavelengths from NIR to MIR that are not easily obtainable from traditional diode pumped solid-state lasers. By replacing the output coupler of the LOLA laser with a properly designed parametric crystal, we successfully demonstrated a monolithic intra-cavity optical parametric oscillator (iOPO) laser based on all high technology readiness level (TRL) subsystems and components. Several desired wavelengths have been generated including 2.1 µm, 2.7 μm and 3.4 μm. This laser can also be used in trace-gas remote sensing, as many molecules possess their unique vibrational transitions in NIR to MIR wavelength region, as well as in time-of-flight mass spectrometer where desorption of samples using MIR laser wavelengths have been successfully demonstrated

  7. A Multi-Wavelength IR Laser for Space Applications

    Science.gov (United States)

    Li, Steven X.; Yu, Anthony W.; Sun, Xiaoli; Fahey, Molly E.; Numata, Kenji; Krainak, Michael A.

    2017-01-01

    We present a laser technology development with space flight heritage to generate laser wavelengths in the near- to mid-infrared (NIR to MIR) for space lidar applications. Integrating an optical parametric crystal to the LOLA (Lunar Orbiter Laser Altimeter) laser transmitter design affords selective laser wavelengths from NIR to MIR that are not easily obtainable from traditional diode pumped solid-state lasers. By replacing the output coupler of the LOLA laser with a properly designed parametric crystal, we successfully demonstrated a monolithic intra-cavity optical parametric oscillator (iOPO) laser based on all high technology readiness level (TRL) subsystems and components. Several desired wavelengths have been generated including 2.1 microns, 2.7 microns and 3.4 microns. This laser can also be used in trace-gas remote sensing, as many molecules possess their unique vibrational transitions in NIR to MIR wavelength region, as well as in time-of-flight mass spectrometer where desorption of samples using MIR laser wavelengths have been successfully demonstrated.

  8. Beginning Objective-C

    CERN Document Server

    Dovey, James

    2012-01-01

    Objective-C is today's fastest growing programming language, at least in part due to the popularity of Apple's Mac, iPhone and iPad. Beginning Objective-C is for you if you have some programming experience, but you're new to the Objective-C programming language and you want a modern-and fast-way forwards to your own coding projects. Beginning Objective-C offers you a modern programmer's perspective on Objective-C courtesy of two of the best iOS and Mac developers in the field today, and gets you programming to the best of your ability in this important language.  It gets you rolling fast into

  9. Space Object Query Tool

    Science.gov (United States)

    Phillips, Veronica J.

    2017-01-01

    STI is for a fact sheet on the Space Object Query Tool being created by the MDC. When planning launches, NASA must first factor in the tens of thousands of objects already in orbit around the Earth. The number of human-made objects, including nonfunctional spacecraft, abandoned launch vehicle stages, mission-related debris and fragmentation debris orbiting Earth has grown steadily since Sputnik 1 was launched in 1957. Currently, the U.S. Department of Defenses Joint Space Operations Center, or JSpOC, tracks over 15,000 distinct objects and provides data for more than 40,000 objects via its Space-Track program, found at space-track.org.

  10. Multi-wavelengths digital holography: reconstruction, synthesis and display of holograms using adaptive transformation.

    Science.gov (United States)

    Memmolo, P; Finizio, A; Paturzo, M; Ferraro, P; Javidi, B

    2012-05-01

    A method based on spatial transformations of multiwavelength digital holograms and the correlation matching of their numerical reconstructions is proposed, with the aim to improve superimposition of different color reconstructed images. This method is based on an adaptive affine transform of the hologram that permits management of the physical parameters of numerical reconstruction. In addition, we present a procedure to synthesize a single digital hologram in which three different colors are multiplexed. The optical reconstruction of the synthetic hologram by a spatial light modulator at one wavelength allows us to display all color features of the object, avoiding loss of details.

  11. Aberration-free ultrathin flat lenses and axicons at telecom wavelengths based on plasmonic metasurfaces.

    Science.gov (United States)

    Aieta, Francesco; Genevet, Patrice; Kats, Mikhail A; Yu, Nanfang; Blanchard, Romain; Gaburro, Zeno; Capasso, Federico

    2012-09-12

    The concept of optical phase discontinuities is applied to the design and demonstration of aberration-free planar lenses and axicons, comprising a phased array of ultrathin subwavelength-spaced optical antennas. The lenses and axicons consist of V-shaped nanoantennas that introduce a radial distribution of phase discontinuities, thereby generating respectively spherical wavefronts and nondiffracting Bessel beams at telecom wavelengths. Simulations are also presented to show that our aberration-free designs are applicable to high-numerical aperture lenses such as flat microscope objectives.

  12. Multi-Wavelength investigation of the co-orbital moons Dione and Helene

    Science.gov (United States)

    Royer, Emilie M.; Hendrix, Amanda R.; Howett, Carly; Spilker, Linda

    2017-10-01

    The icy satellites Dione and Helene share the same orbit, at 6.26 Saturn radii from the giant planet, which is within Saturn’s diffuse E ring. Helene is one of Dione’s two Trojan moons, located in the leading Lagrangian point L4 of Dione’s orbit. We present here preliminary results on the investigation of the Dione-Helene duo in term of origin, formation and evolution. Specifically, the key objectives are to retrieve the photometric properties and composition of the moons to answer questions such as: Are the Dione and Helene surfaces made of the same material? Did they form in the same region of the Solar System? Is one satellite older than the other? Have they experienced the same amount of space weathering?To provide the most complete evaluation of the Dione and Helene surfaces and advance our understanding of how exogenic processes affect the surfaces of icy satellites we use the synergy of four of the Cassini instruments: UVIS (Ultraviolet Imaging Spectrograph), ISS (Imaging Science Subsystem), VIMS (Visual and Infrared Mapping Spectrometer) and CIRS (Composite Infrared Spectrometer). Composite disk-integrated spectra of both moons have been produced to conduct spectral modeling over a large wavelength range from the ultraviolet to the infrared, from 111nm to 1mm. Until now, most investigations have focused only on one wavelength domain, telling only part of the story. A multi-wavelength analysis allows an in-depth investigation of the surfaces of the Saturnian satellites as each wavelength probes a different layer of the surface. Special attention is directed toward the search for correlations of basic properties (albedo, scattering properties, texture, grain size, composition, porosity, thermal properties) between Dione and Helene.

  13. Millimeter and submillimeter wave ESR measurement of Ho{sub 2}Cu{sub 2}O{sub 5} aligned powder sample

    Energy Technology Data Exchange (ETDEWEB)

    Okubo, S. [Kobe Univ., Graduate School of Science and Technology, Kobe, Hyogo (Japan); Goto, T.; Tanaka, T.; Ohta, H. [Kobe Univ. (Japan). Dept. of Physics; Mogi, I.; Watanabe, K.; Motokawa, M. [Tohoku Univ., Sendai (Japan). Inst. for Materials Research

    1999-07-01

    To gain information of anisotropy of Ho{sub 2}Cu{sub 2}O{sub 5} the aligned powder sample was prepared under the static high magnetic field of 5T. Millimeter and submillimeter wave ESR measurements of aligned Ho{sub 2}Cu{sub 2}O{sub 5} samples have been performed for the first time in the frequency region from 50 to 430 GHz using the pulsed magnetic field up to 16T at 1.8K. Antiferromagnetic resonances were observed clearly at 1.8K. AFMR modes of easy axis change at two critical fields. The temperature dependence measurements were also performed and the Neel temperature of the system is discussed. (author)

  14. Metrology test object for dimensional verification in additive manufacturing of metals for biomedical applications.

    Science.gov (United States)

    Teeter, Matthew G; Kopacz, Alexander J; Nikolov, Hristo N; Holdsworth, David W

    2015-01-01

    Additive manufacturing continues to increase in popularity and is being used in applications such as biomaterial ingrowth that requires sub-millimeter dimensional accuracy. The purpose of this study was to design a metrology test object for determining the capabilities of additive manufacturing systems to produce common objects, with a focus on those relevant to medical applications. The test object was designed with a variety of features of varying dimensions, including holes, cylinders, rectangles, gaps, and lattices. The object was built using selective laser melting, and the produced dimensions were compared to the target dimensions. Location of the test objects on the build plate did not affect dimensions. Features with dimensions less than 0.300 mm did not build or were overbuilt to a minimum of 0.300 mm. The mean difference between target and measured dimensions was less than 0.100 mm in all cases. The test object is applicable to multiple systems and materials, tests the effect of location on the build, uses a minimum of material, and can be measured with a variety of efficient metrology tools (including measuring microscopes and micro-CT). Investigators can use this test object to determine the limits of systems and adjust build parameters to achieve maximum accuracy. © IMechE 2014.

  15. Unifying Subjectivity and Objectivity

    Directory of Open Access Journals (Sweden)

    Murugesan Chandrasekaran

    2016-10-01

    Full Text Available The contribution of modern science to the progress of civilization is immeasurable. Even its tendency toward exclusive concentration on the objective world has had salutary effects of great value. Modern science has wiped away much that was merely superstitious or speculative. Its rejection of unfounded opinions and prejudices has helped the thinking mind question conventional beliefs, shed preferences and prejudices, and challenge established authority. But modern systems thinking inherited from natural science is the suppression of the subjective dimension of reality. Many complex systems are an attempt to define and represent all subjective experience in physical terms. The modern man has a bias towards objectivity. The powerful influence of sense impressions on his mind and thinking makes him ignore the subjective experience and consider only objective facts as a valid, legitimate and representation of reality. Observing objective factors that are physical is easier than observing subjective factors that are subtle. The mechanistic view of reality has led to the rejection of the role of the individual in social development as insignificant. The individuals determine the development of society. Their social power has its roots both in subjective factors and objective factors. Economy, politics, society, and culture are inseparable dimensions of a single integrated reality. Subject and object constitute an integrated whole. The mind sees them as separate and independent. Or it views one as completely subordinate to the other. Unbiased approach to the study of all human experiences may prove that subject and object are interdependent dimensions or elements of reality.

  16. On Coordinating Collaborative Objects

    Directory of Open Access Journals (Sweden)

    Abdessamad Imine

    2010-07-01

    Full Text Available A collaborative object represents a data type (such as a text document designed to be shared by a group of dispersed users. The Operational Transformation (OT is a coordination approach used for supporting optimistic replication for these objects. It allows the users to concurrently update the shared data and exchange their updates in any order since the convergence of all replicas, i.e. the fact that all users view the same data, is ensured in all cases. However, designing algorithms for achieving convergence with the OT approach is a critical and challenging issue. In this paper, we propose a formal compositional method for specifying complex collaborative objects. The most important feature of our method is that designing an OT algorithm for the composed collaborative object can be done by reusing the OT algorithms of component collaborative objects. By using our method, we can start from correct small collaborative objects which are relatively easy to handle and incrementally combine them to build more complex collaborative objects.

  17. Particle image velocimetry based on wavelength division multiplexing

    Science.gov (United States)

    Tang, Chunxiao; Li, Enbang; Li, Hongqiang

    2018-01-01

    This paper introduces a technical approach of wavelength division multiplexing (WDM) based particle image velocimetry (PIV). It is designed to measure transient flows with different scales of velocity by capturing multiple particle images in one exposure. These images are separated by different wavelengths, and thus the pulse separation time is not influenced by the frame rate of the camera. A triple-pulsed PIV system has been created in order to prove the feasibility of WDM-PIV. This is demonstrated in a sieve plate extraction column model by simultaneously measuring the fast flow in the downcomer and the slow vortices inside the plates. A simple displacement/velocity field combination method has also been developed. The constraints imposed by WDM-PIV are limited wavelength choices of available light sources and cameras. The usage of WDM technique represents a feasible way to realize multiple-pulsed PIV.

  18. Resonance fluorescence from a telecom-wavelength quantum dot

    CERN Document Server

    Al-Khuzheyri, R; Huwer, J; Santana, T S; Szymanska, J Skiba-; Felle, M; Ward, M B; Stevenson, R M; Farrer, I; Tanner, M G; Hadfield, R H; Ritchie, D A; Shields, A J; Gerardot, B D

    2016-01-01

    We report on resonance fluorescence from a single quantum dot emitting at telecom wavelengths. We perform high-resolution spectroscopy and observe the Mollow triplet in the Rabi regime--a hallmark of resonance fluorescence. The measured resonance-fluorescence spectra allow us to rule out pure dephasing as a significant decoherence mechanism in these quantum dots. Combined with numerical simulations, the experimental results provide robust characterisation of charge noise in the environment of the quantum dot. Resonant control of the quantum dot opens up new possibilities for on-demand generation of indistinguishable single photons at telecom wavelengths as well as quantum optics experiments and direct manipulation of solid-state qubits in telecom-wavelength quantum dots.

  19. Effect of graphene on plasmonic metasurfaces at infrared wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Shinpei, E-mail: Ogawa.Shimpei@eb.MitsubishiElectric.co.jp; Fujisawa, Daisuke; Ueno, Masashi [Advanced Technology R and D Center, Mitsubishi Electric Corporation, 8-1-1 Tsukaguchi-Honmachi, Amagasaki, Hyogo 661-8661 (Japan)

    2013-11-15

    Significant enhancement of infrared transmittance by the presence of a graphene layer on a plasmonic metasurface (PLM) has been demonstrated. PLMs with different configurations were fabricated, and their transmittance with and without graphene was compared. Selective enhancement by graphene occurred at the plasmon resonance wavelength. The degree of enhancement was found to depend on the width of the gap between the periodic metal regions in the PLM. A maximum enhancement of ∼210% was achieved at a wavelength of 10 μm. The ability to achieve such a drastic increase in transmittance at the plasmon resonant wavelength is expected to lead to improvements in the performance of energy collecting devices and optical sensors.

  20. The extra-terrestrial vacuum-ultraviolet wavelength range

    Science.gov (United States)

    Timothy, J. Gethyn; Wilhelm, Klaus; Xia, Lidong

    Electromagnetic radiation in the vacuum-ultraviolet (VUV) and extra-terrestrial range at wavelengths from 10 nm to 300 nm is absorbed in the upper atmosphere by ozone, molecular and atomic oxygen, and molecular nitrogen. Observations at wavelengths down to ≈ 200 nm can be carried out from stratospheric balloons, and observations below 200 nm require space platforms operating at altitudes above 250 km. The VUV spectral region contains emission lines and continua arising from plasma at formation temperatures ranging from about 104 K to more than 107 K. This chapter describes the wide range of plasma diagnostic techniques available at VUV wavelengths, and the development of instrumentation for studies of the high-temperature solar outer atmosphere and astrophysical plasmas. Finally, the prospects for future studies are briefly discussed.

  1. Do shorter wavelengths improve contrast in optical mammography?

    Energy Technology Data Exchange (ETDEWEB)

    Taroni, P [INFM-Dipartimento di Fisica and IFN-CNR, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milan (Italy); Pifferi, A [INFM-Dipartimento di Fisica and IFN-CNR, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milan (Italy); Torricelli, A [INFM-Dipartimento di Fisica and IFN-CNR, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milan (Italy); Spinelli, L [INFM-Dipartimento di Fisica and IFN-CNR, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milan (Italy); Danesini, G M [Dipartimento di Radiologia, Casa di Cura S.Pio X, via Francesco Nava 31, I-20159 Milan (Italy); Cubeddu, R [INFM-Dipartimento di Fisica and IFN-CNR, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milan (Italy)

    2004-04-07

    The detection of tumours with time-resolved transmittance imaging relies essentially on blood absorption. Previous theoretical and phantom studies have shown that both contrast and spatial resolution of optical images are affected by the optical properties of the background medium, and high absorption and scattering are generally beneficial. Based on these observations, wavelengths shorter than presently used (680-780 nm) could be profitable for optical mammography. A study was thus performed analysing time-resolved transmittance images at 637, 656, 683 and 785 nm obtained from 26 patients bearing 16 tumours and 15 cysts. The optical contrast proved to increase upon decreasing wavelengths for the detection of cancers in late-gated intensity images, with higher gain in contrast for lesions of smaller size (<1.5 cm diameter). For cysts either a progressive increase or decrease in contrast with wavelength was observed in scattering images.

  2. Slot-grating flat lens for telecom wavelengths.

    Science.gov (United States)

    Pugh, Jonathan R; Stokes, Jamie L; Lopez-Garcia, Martin; Gan, Choon-How; Nash, Geoff R; Rarity, John G; Cryan, Martin J

    2014-07-01

    We present a stand-alone beam-focusing flat lens for use in the telecommunications wavelength range. Light incident on the back surface of the lens propagates through a subwavelength aperture and is heavily diffracted on exit and partially couples into a surface plasmon polariton and a surface wave propagating along the surface of the lens. Interference between the diffracted wave and re-emission from a grating patterned on the surface produces a highly collimated beam. We show for the first time a geometry at which a lens of this type can be used at telecommunication wavelengths (λ=1.55 μm) and identify the light coupling and re-emission mechanisms involved. Measured beam profile results at varying incident wavelengths show excellent agreement with Lumerical FDTD simulation results.

  3. Photonic digital-to-analog conversion based on wavelength multiplexing

    Science.gov (United States)

    Yang, Shuna; Hu, Miao; Chi, Hao; Li, Qiliang

    2017-10-01

    A novel photonic digital-to-analog conversion (PDAC) scheme, which is based on optical intensity weighting and multiplexing/summing of different wavelengths, is proposed. The employment of wavelength multiplexing in the system, which conducts the function of modulated light intensity summation, greatly simplifies the system complexity and improves the conversion speed/accuracy limited by large-area photo-detectors and associated electronics. A 4-bit PDAC with a conversion speed of 10 GS/s demonstrates the feasibility of the proposed scheme. In addition, the performance degradation induced by the limited extinction ratios of the applied electro-optic modulators, the synchronization errors among different wavelength channels, and the bit resolutions of the built system is also discussed.

  4. Enhanced Plasmonic Wavelength Selective Infrared Emission Combined with Microheater

    Directory of Open Access Journals (Sweden)

    Hiroki Ishihara

    2017-09-01

    Full Text Available The indirect wavelength selective thermal emitter that we have proposed is constructed using a new microheater, demonstrating the enhancement of the emission peak generated by the surface plasmon polariton. The thermal isolation is improved using a 2 μm-thick Si membrane having 3.6 and 5.4 mm outer diameter. The emission at around the wavelength of the absorption band of CO2 gas is enhanced. The absorption signal increases, confirming the suitability for gas sensing. Against input power, the intensity at the peak wavelength shows a steeper increasing ratio than the background intensity. The microheater with higher thermal isolation gives larger peak intensity and its increasing ratio against the input power.

  5. Effect of graphene on plasmonic metasurfaces at infrared wavelengths

    Directory of Open Access Journals (Sweden)

    Shinpei Ogawa

    2013-11-01

    Full Text Available Significant enhancement of infrared transmittance by the presence of a graphene layer on a plasmonic metasurface (PLM has been demonstrated. PLMs with different configurations were fabricated, and their transmittance with and without graphene was compared. Selective enhancement by graphene occurred at the plasmon resonance wavelength. The degree of enhancement was found to depend on the width of the gap between the periodic metal regions in the PLM. A maximum enhancement of ∼210% was achieved at a wavelength of 10 μm. The ability to achieve such a drastic increase in transmittance at the plasmon resonant wavelength is expected to lead to improvements in the performance of energy collecting devices and optical sensors.

  6. Short Wavelength Seeding through Compression for Fee Electron Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Ji

    2010-03-29

    In this paper, we propose a seeding scheme that compresses an initial laser modulation in the longitudinal phase space of an electron beam by using two opposite sign bunch compressors and two opposite sign energy chirpers. This scheme could potentially reduce the initial modulation wavelength by a factor of C and increase the energy modulation amplitude by a factor of C , where Cis the compression factor of the first bunch compressor. Using two lasers as energy chirpers, such a modulation compression scheme can generate kilo-Ampershort wavelength current modulation with significant bunching factor from an initial a few tens Amper current. This compression scheme can also be used togenerate a prebunched single atto-second short wavelength current modulation and prebunched two color, two atto-second modulations.

  7. Magic wavelengths of the Ca+ ion for circularly polarized light

    Science.gov (United States)

    Jiang, Jun; Jiang, Li; Wang, Xia; Zhang, Deng-Hong; Xie, Lu-You; Dong, Chen-Zhong

    2017-10-01

    The dynamic dipole polarizabilities of low-lying states of Ca+ ions for circularly polarized light are calculated by using the relativistic configuration interaction plus core polarization approach. The magic wavelengths are determined for the magnetic sublevel transitions 4 s1/2 ,m→4 pj',m' and 4 s1/2 ,m→3 dj',m' with total angular momentum j' and its components m'. In contrast to the case of linearly polarized light, several additional magic wavelengths are found for these transitions. We suggest that accurate measurements on the magic wavelengths near 851 nm for the 4 s1/2 ,m→4 p3/2 ,m' transitions can be used to determine the ratio of the oscillator strengths for the 4 p3/2→3 d3/2 and 4 p3/2→3 d5/2 transitions.

  8. In-vacuum long-wavelength macromolecular crystallography.

    Science.gov (United States)

    Wagner, Armin; Duman, Ramona; Henderson, Keith; Mykhaylyk, Vitaliy

    2016-03-01

    Structure solution based on the weak anomalous signal from native (protein and DNA) crystals is increasingly being attempted as part of synchrotron experiments. Maximizing the measurable anomalous signal by collecting diffraction data at longer wavelengths presents a series of technical challenges caused by the increased absorption of X-rays and larger diffraction angles. A new beamline at Diamond Light Source has been built specifically for collecting data at wavelengths beyond the capability of other synchrotron macromolecular crystallography beamlines. Here, the theoretical considerations in support of the long-wavelength beamline are outlined and the in-vacuum design of the endstation is discussed, as well as other hardware features aimed at enhancing the accuracy of the diffraction data. The first commissioning results, representing the first in-vacuum protein structure solution, demonstrate the promising potential of the beamline.

  9. Structure-Optical Property Correlations of Arsenic Sulfide Glasses in Visible, Infrared, and Sub-millimeter Regions

    Energy Technology Data Exchange (ETDEWEB)

    McCloy, John S.; Riley, Brian J.; Sundaram, S. K.; Qiao, Hong (Amy); Crum, Jarrod V.; Johnson, Bradley R.

    2010-06-01

    Optical properties and structural aspects of AsxS100-x glasses from visible to terahertz wavelengths were explored. A series of annealed, bulk AsxS100-x glasses (x = 30 to 42) were made and their refractive indices determined at terahertz, infrared, and visible frequencies using a combination of a quasi-optical backwards wave oscillator spectrometer for terahertz measurements and a prism coupler for visible and infrared measurements. It was found that refractive index at all frequencies increases with arsenic composition up to 40 atomic % arsenic then decreases with additional arsenic. Structure in x-ray diffraction patterns support the notion of a minimum volume at 40 atomic %, while the average covalent coordination number indicates the rigidity percolation threshold is reached there. At As concentrations > 40 atomic %, the network becomes over-constrained, the molar volume increases.

  10. Functional Object Analysis

    DEFF Research Database (Denmark)

    Raket, Lars Lau

    We propose a direction it the field of statistics which we will call functional object analysis. This subfields considers the analysis of functional objects defined on continuous domains. In this setting we will focus on model-based statistics, with a particularly emphasis on mixed......-effect formulations, where the observed functional signal is assumed to consist of both fixed and random functional effects. This thesis takes the initial steps toward the development of likelihood-based methodology for functional objects. We first consider analysis of functional data defined on high...

  11. [Achievement of therapeutic objectives].

    Science.gov (United States)

    Mantilla, Teresa

    2014-07-01

    Therapeutic objectives for patients with atherogenic dyslipidemia are achieved by improving patient compliance and adherence. Clinical practice guidelines address the importance of treatment compliance for achieving objectives. The combination of a fixed dose of pravastatin and fenofibrate increases the adherence by simplifying the drug regimen and reducing the number of daily doses. The good tolerance, the cost of the combination and the possibility of adjusting the administration to the patient's lifestyle helps achieve the objectives for these patients with high cardiovascular risk. Copyright © 2014 Sociedad Española de Arteriosclerosis y Elsevier España, S.L. All rights reserved.

  12. Scanning SQUID microscopy as a new tool for sub-millimeter scale magnetostratigraphy: An application to unveil the growth process of marine ferromanganese crusts and its future potential

    Science.gov (United States)

    Oda, H.; Noguchi, A.; Yamamoto, Y.; Usui, A.; Sato, M.; Kawai, J.

    2016-12-01

    Scanning SQUID microscope, a new developing tool for paleomagnetists, enables us to map magnetic field on surfaces of geological samples or thin sections at sub-millimeter scale and provides opportunity to conduct magnetostratigraphy with an unprecedented resolution. In the presentation, we show an example of sub-millimeter scale magnetostratigraphy with a newly developed scanning SQUID (superconducting quantum interference device) microscope (SSM) at Geological Survey, AIST (Kawai et al., 2016; Oda et al., submitted). Marine ferromanganese crusts grow very slowly throughout the global ocean by direct precipitation typically on seamounts for more than several tens of millions of years, which can be considered as archives of paleoclimate and paleoceanography.In order to uncover the history of paleoenvironment recorded in the ferromanganese cursts, it is very important to provide their reliable age models and growth rates. Previous studies have shown universal applicability of magnetostratigraphy in estimating growth ages of ferromanganese crust (Oda et al., 2011; Noguchi et al., in press). A thin section of a ferromanganese crust sample from Takuyo-Daigo seamount in northwest Pacific was used for the mapping of magnetic field with the SSM, where minimum amount of dust and sediment are expected to come from continents. The result shows that average growth rate of the ferromanganese crust from this seamount is 3.56 ± mm/m.y., which is within 17.6% of that deduced from the 10Be/9Be dating method (2.93 ±0.15 mm/m.y.). Although the mechanism of remanent magnetization acquisition for ferromanganese crusts need to be investigated further, the magnetic stripes parallel to the growth pattern observed on optical and backscattered electron images promises the future possibilities to provide a quick tool to estimate ages and growth rates for ferromanganese crusts. Finally, it can be concluded that SSM could be a fundamental tool for paleomagnetists in providing avenue to

  13. TU-H-CAMPUS-TeP2-03: High Sensitivity and High Resolution Fiber Based Micro-Detector for Sub-Millimeter Preclinical Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Izaguirre, E; Pokhrel, S; Knewtson, T [University of Tennessee Medical Science Center, Memphis, TN (United States); University of Missouri, Columbia, MO (United States); Hedrick, S [Provision Center for Proton Therapy, Knoxville, TN (United States)

    2016-06-15

    Purpose: Current precision of small animal and cell micro-irradiators has continuously increased during the past years. Currently, preclinical irradiators can deliver sub-millimeter fields with micrometric precision but there are no water equivalent dosimeters to determine small field profiles and dose in the orthovoltage range of energies with micrometric resolution and precision. We have developed a fiber based micro-dosimeter with the resolution and dosimetric accuracy required for radiobiological research. Methods: We constructed two prototypes of micro-dosimeters based on different compositions of fiber scintillators to study the spatial resolution and dosimetric precision of small animal and cell micro-irradiators. The first has green output and the second has blue output. The blue output dosimeter has the highest sensitivity because it matches the spectral sensitivity of silicon photomultipliers. A blue detector with 500um cross section was built and tested respect to a CC01 ion chamber, film, and the 1500um green output detector. Orthovoltage fields from 1×1mm2 to 5×5mm2 were used for detector characteristics comparison. Results: The blue fiber dosimeter shows great agreement with films and matches dose measurements with the gold-standard ion chamber for 5×5mm2 fields. The detector has the appropriate sensitivity to measure fields from 1×1mm2 to larger sizes with a 1% dosimetric accuracy. The spatial resolution is in the sub-millimeter range and the spectral matching with the photomultiplier allows reducing the sensor cross section even further than the presented prototype. These results suggest that scintillating fibers combined with silicon photomultipliers is the appropriate technology to pursue micro-dosimetry for small animals and disperse cell samples. Conclusion: The constructed detectors establish a new landmark for the resolution and sensitivity of fiber based microdetectors. The validation of the detector in our small animal and cell

  14. Accurate wavelength calibration method for compact CCD spectrometer.

    Science.gov (United States)

    Sun, Y C; Huang, C; Xia, G; Jin, S Q; Lu, H B

    2017-04-01

    Wavelength calibration is an important step in charge-coupled device (CCD) spectrometers. In this paper, an accurate calibration method is proposed. A model of a line profile spectrum is built at the beginning, followed by noise reduction, bandwidth correction, and automatic peak-seeking treatment. Experimental tests are conducted on the USB4000 spectrometer with a mercury-argon calibration light source. Compared with the traditional method, the results show that this wavelength calibration procedure obtains higher accuracy and the deviations are within 0.1 nm.

  15. Negative refraction at telecommunication wavelengths through plasmon-photon hybridization.

    Science.gov (United States)

    Kalusniak, Sascha; Sadofev, Sergey; Henneberger, Fritz

    2015-11-16

    We demonstrate negative refraction at telecommunication wavelengths through plasmon-photon hybridization on a simple microcavity with metallic mirrors. Instead of using conventional metals, the plasmonic excitations are provided by a heavily doped semiconductor which enables us to tune them into resonance with the infrared photon modes of the cavity. In this way, the dispersion of the resultant hybrid cavity modes can be widely adjusted. In particular, negative dispersion and negative refraction at telecommunication wavelengths on an all-ZnO monolithical cavity are demonstrated.

  16. Nonstandard FDTD Simulation-Based Design of CROW Wavelength Splitters

    Directory of Open Access Journals (Sweden)

    Naoki Okada

    2011-01-01

    Full Text Available The finite-difference time-domain (FDTD algorithm has been used in simulation-based designs of many optical devices, but it fails to reproduce high-Q whispering gallery modes (WGMs. On the other hand, the nonstandard (NS FDTD algorithm can accurately compute WGMs and can be used to make simulation-based designs of WGM devices. Wavelength splitters using the coupled resonator optical waveguides (CROWs based on WGM couplings have recently attracted attention because they are potentially ultracompact. In this paper, we design a CROW wavelength splitter using NS FDTD simulations and demonstrate high interchannel extinction ratios of over 20 dB.

  17. Algorithm for Implementation of Wavelength Division Multiplexing in EPON

    Directory of Open Access Journals (Sweden)

    P. S. Matavulj

    2010-06-01

    Full Text Available Today, implementation of wavelength division multiplexing in the Ethernet passive optical network (EPON is considered as one of the most perspective solutions for the bottleneck problem in the access network. With the development of new applications and services, multimedia applications above all, quality of service (QoS support becomes a major concern in WDM EPON, as it was the case in EPON. In this paper, WDM EPON architecture is presented along with a novel algorithm for wavelength and bandwidth allocation with full QoS support. Besides theoretical analysis, simulation results are presented and they confirm a good performance of presented solution.

  18. 3D geometrically isotropic metamaterial for telecom wavelengths

    DEFF Research Database (Denmark)

    Malureanu, Radu; Andryieuski, Andrei; Lavrinenko, Andrei

    2009-01-01

    We present a new design for a unit cell with the cubic symmetry and sizes less than one sixth of the vacuum wavelength possessing a negative refractive index in the IR region. The main challenges in designing and fabricating metamaterials nowadays are in obtaining isotropic electric and magnetic......). At this wavelength the refraction index is equal to -1.44. These values together with the effective cubic symmetry of the unit cell entitle us to assume the high potential of the suggested design as a constitutive block for an isotropic, relatively low-loss, metamaterial in the near IR region....

  19. Properties of Sub-wavelength Resonances in Metamaterial Cylinders

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Clausen, N.C.J.; Pedersen, R.R.

    2008-01-01

    The analytical solution for the canonical configuration with electric line source illumination of concentric metamaterial cylinders is employed to study the properties of the observed sub-wavelength resonances. The near- and far-field distributions, the frequency and geometry bandwidths, and the ......The analytical solution for the canonical configuration with electric line source illumination of concentric metamaterial cylinders is employed to study the properties of the observed sub-wavelength resonances. The near- and far-field distributions, the frequency and geometry bandwidths......, and the line source impedance are investigated for varying electromagnetic and geometrical parameters. The results of this study are of importance for metamaterial-based miniaturization of antennas....

  20. Optimal laser wavelength for photoacoustic imaging of breast microcalcifications

    Science.gov (United States)

    Kang, Jeeun; Kim, Eun-Kyung; Young Kwak, Jin; Yoo, Yangmo; Song, Tai-Kyong; Ho Chang, Jin

    2011-10-01

    This paper presents photoacoustic imaging (PAI) for real-time detection of micro-scale calcifications (e.g., breast, which are an indicator of the cancer occurrence. Optimal wavelength of incident laser for the microcalcification imaging was ascertained through ex vivo experiments with seven breast specimens of volunteers. In the ex vivo experiments, the maximum amplitude of photoacoustic signals from the microcalcifications occurred when the laser wavelength ranged from 690 to 700 nm. This result demonstrated that PAI can serve as a real-time imaging and guidance tool for diagnosis and biopsy of the breast microcalcifications.