Far infrared peculiar behavior of quasars

International Nuclear Information System (INIS)

Liu Yulin; Liu Jiying

1988-09-01

Many quasars possibly have nebulous envelopes with far infrared radiation. These nebulosities may be similar to fuzz in the optical region in morphology. These quasars have many properties in common. (author). Refs, 3 figs

Development of an optical resonator with high-efficient output coupler for the JAERI far-infrared free-electron laser

International Nuclear Information System (INIS)

Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki; Sawamura, Masaru; Kikuzawa, Nobuhiro; Shizuma, Toshiyuki; Minehara, Eisuke

2001-01-01

An optical resonator with a high-efficient output coupler was developed for the JAERI far-infrared free-electron laser. The optical resonator is symmetrical near-concentric geometry with an insertable scraper output coupler. As a result of the development of the optical resonator, the JAERI-FEL has been successfully, lased with averaged power over 1 kW. Performance of the optical resonator with the output coupler was evaluated at optical wavelength of 22 μm by using an optical mode calculation code. The output coupling and diffractive loss with a dominant eigen-mode of the resonator were calculated using an iterative computation called Fox-Li procedure. An efficiency factor of the optical resonator was introduced for the evaluation of the optical resonator performance. The efficiency factor was derived by the amount of the output coupling and diffractive loss of the optical resonator. It was found that the optical resonator with the insertable scraper coupler was the most suitable to a high-power and high-efficient far-infrared free-electron laser. (author)

Optically pumped FIR lasers and their application in plasma diagnostics

International Nuclear Information System (INIS)

Bakos, J.S.

1986-06-01

The pysics and the construction of the far infrared lasers (FIRL) and of the infrared lasers pumping them are reviewed. The details of the construction, resonating and pumping systems, spectral and power characteristics of the FIRLs are discussed. Recently more than 1000 laser lines are known and used in the 27-80 mm wavelength range, but in many cases the laser kinetics are not fully understood, and some instability phenomena cannot be prevented. New nonlinear processes were found: two-photon pumping, hyper Raman laser tuning and relaxation phenomena. A broad application field, the plasma diagnostics by far infrared lasers is described. Scattering of infrared laser radiation can give new interesting information on the not understood effect of the anomalous transport in the high temperature plasma. (D.Gy.)

Far infrared observations of the galactic center

International Nuclear Information System (INIS)

Gatley, I.

1977-01-01

Maps of a region 10' in diameter around the galactic center made simultaneously in three wavelength bands at 30 μm, 50 μm, and 100 μm with approximately 1' resolution are presented, and the distribution of far infrared luminosity and color temperature across this region is derived. The position of highest far infrared surface brightness coincides with the peak of the late-type stellar distribution and with the H II region Sgr A West. The high spatial and temperature resolution of the data is used to identify features of the far infrared maps with known sources of near infrared, radio continuum, and molecular emission. The emission mechanism and energy sources for the far infrared radiation are anslyzed qualitatively, and it is concluded that all of the observed far infrared radiation from the galactic center region can be attributed to thermal emission from dust heated both by the late-type stars and by the ultraviolet sources which ionize the H II regions. A self-consistent model for the far infrared emission from the galactic center region is presented. It is found that the visual extinction across the central 10 pc of the galaxy is only about 3 magnitudes, and that the dust density is fairly uniform in this region. An upper limit of 10 7 L/sub mass/ is set on the luminosity of any presently unidentified source of 0.1 to 1 μm radiation at the galactic center. Additional maps in the vicinity of the source Sgr B2 and observations of Sgr C bring the total number of H II regions within 1 0 of the galactic center studied by the present experiment to nine. The far infrared luminosity, color temperature and optical depth of these regions and the ratio of infrared flux to radio continuum flux lie in the range characteristic of spiral arm H II regions. The far infrared results are therefore consistent with the data that the galactic center H II regions are ionized by luminous, early type stars

Far-infrared /FIR/ optical black bidirectional reflectance distribution function /BRDF/

Science.gov (United States)

Smith, S. M.

1981-01-01

A nonspecular reflectometer and its operation at far-infrared wavelengths are described. Large differences in nonspecular reflectance were found to exist between different optically black coatings. Normal incidence bidirectional reflectance distribution function /BRDF) measurements at wavelengths between 12 and 316 microns of three black coatings show that their mean BRDFs increase with wavelength. The specularity of two of these coatings also showed a strong wavelength dependence, while the specularity of one coating seemed independent of wavelength. The BRDF of one coating depended on the angle of incidence at 12 and 38 microns, but not at 316 microns. Beyond 200 microns, it was found necessary to correct the measurements for the beam spread of the instrument.

Far-Infrared Magneto-Optical Studies in Germanium and Indium-Antimonide at High Intensities

Science.gov (United States)

Leung, Michael

Observations of nonlinear magneto-optical phenomena occurring in p-type Germanium and n-type Indium Antimonide are reported. These include multi-photon ionization of impurity states, and a new observation, the magneto-photon ionization of impurity states, and a new observation, the magneto-photon drag effect. A novel source of far-infrared radiation has been used. This source uses a pulsed CO(,2) LASER to optically pump a super-radiant cell, generating light with intensities up to 100 KW/cm('2) and wavelengths from 66 (mu)m to 496 (mu)m in a pulse of 150 nanoseconds duration. The Germanium samples were doped with Gallium, which is a shallow acceptor with an ionization potential of 11 meV. At liquid Helium temperature virtually all charge carriers are bound to acceptor sites. However, the high intensity radiation unexpectedly ionizes the acceptors. This is demonstrated through measurements of photoconductivity, transmission and the photo-Hall Effect. This observation is unexpected because the photon energy is one-fourth the ionization potential. Rate equations describing sequential multiphoton excitations are in agreement with the experimental results. The intermediate states are postulated to be acceptor exciton band states. Studies of the photoexcited mobility at 496 (mu)m suggest that at non-saturating levels of photoexcitation, the primary scattering mechanism of hot holes in Germanium is by neutral impurities. A new magneto-optical effect, the magneto-photon drag effect, has been studied in both Germanium and Indium Antimonide. This is simply the absorption of momentum by free carriers, from an incident photon field. It has been found that the mechanism for this effect is different in the two materials. In Germanium, the effect occurs when carriers make optical transitions from the heavy hole band to the light hole band. Thus, the magneto-optical behavior depends heavily upon the band structure. On the other hand, a modified Drude model (independent electron

Emission characteristics of the Yb3+-sensitized Tm3+-doped optical fiber upon pumping with infrared LED

International Nuclear Information System (INIS)

Htein, Lin; Fan, Weiwei; Han, Won-Taek

2014-01-01

Near infrared emissions at 975, 1040 and 1450 nm of the Yb 3+ -sensitized Tm 3+ -doped optical fiber were obtained upon simultaneous excitation of Yb 3+ and Tm 3+ ions using the infrared LED. -- Highlights: • A novel pumping scheme for 1450 nm emission from 3 H 4 → 3 F 4 transition of Tm was demonstrated. • The absorption bands of Yb and Tm located within 690–970 nm were simultaneously excited with the IR LED. • Near infrared emissions at 975, 1040 and 1450 nm were obtained. • The Yb 3+ /Tm 3+ -codoped fiber showed the good spectroscopic quality and the increase of radiative lifetime of 3 H 4 level. • This LED pumping scheme can be useful for low-cost S-band fiber laser/amplifier applications

Multi-layer Far-Infrared Component Technology, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Phase I SBIR will demonstrate the feasibility of a process to create multi-layer thin-film optics for the far-infrared/sub-millimeter wave spectral region. The...

Toward power scaling in an acetylene mid-infrared hollow-core optical fiber gas laser: effects of pressure, fiber length, and pump power

Science.gov (United States)

Weerasinghe, H. W. Kushan; Dadashzadeh, Neda; Thirugnanasambandam, Manasadevi P.; Debord, Benoît.; Chafer, Matthieu; Gérôme, Frédéric; Benabid, Fetah; Corwin, Kristan L.; Washburn, Brian R.

2018-02-01

The effect of gas pressure, fiber length, and optical pump power on an acetylene mid-infrared hollow-core optical fiber gas laser (HOFGLAS) is experimentally determined in order to scale the laser to higher powers. The absorbed optical power and threshold power are measured for different pressures providing an optimum pressure for a given fiber length. We observe a linear dependence of both absorbed pump energy and lasing threshold for the acetylene HOFGLAS, while maintaining a good mode quality with an M-squared of 1.15. The threshold and mode behavior are encouraging for scaling to higher pressures and pump powers.

Far infrared supplement: Catalog of infrared observations, second edition

International Nuclear Information System (INIS)

Gezari, D.Y.; Schmitz, M.; Mead, J.M.

1988-08-01

The Far Infrared Supplement: Catalog of Infrared Observations summarizes all infrared astronomical observations at far infrared wavelengths (5 to 1000 microns) published in the scientific literature from 1965 through 1986. The Supplement list contain 25 percent of the observations in the full Catalog of Infrared Observations (CIO), and essentially eliminates most visible stars from the listings. The Supplement is thus more compact than the main catalog, and is intended for easy reference during astronomical observations. The Far Infrared Supplement (2nd Edition) includes the Index of Infrared Source Positions and the Bibliography of Infrared Astronomy for the subset of far infrared observations listed

Far-infrared elastic scattering proposal for the Avogadro Project's silicon spheres

Science.gov (United States)

Humayun, Muhammad Hamza; Khan, Imran; Azeem, Farhan; Chaudhry, Muhammad Rehan; Gökay, Ulaş Sabahattin; Murib, Mohammed Sharif; Serpengüzel, Ali

2018-05-01

Avogadro constant determines the number of particles in one mole of a substance, thus relating the molar mass of the substance to the mass of this substance. Avogadro constant is related to Système Internationale base units by defining the very concept of chemical quantity. Revisions of the base units created a need to redefine the Avogadro constant, where a collaborative work called the Avogadro Project is established to employ optical interferometry to measure the diameter of high quality 100 mm silicon spheres. We propose far-infrared spectroscopy for determining the Avogadro constant by using elastic scattering from the 100 mm Avogadro Project silicon spheres. Similar spectroscopic methods are already in use in the near-infrared, relating whispering gallery modes of the 1 mm silicon spheres to the diameter of the spheres. We present numerical simulations in the far-infrared and the near-infrared, as well as spatially scaled down elastic scattering measurements in the near-infrared. These numerical and experimental results show that, the diameter measurements of 100 mm single crystal silicon spheres with elastic scattering in the far-infrared can be considered as an alternative to optical interferometry.

Optically pumped terahertz sources

Institute of Scientific and Technical Information of China (English)

ZHONG Kai; SHI Wei; XU DeGang; LIU PengXiang; WANG YuYe; MEI JiaLin; YAN Chao; FU ShiJie; YAO JianQuan

2017-01-01

High-power terahertz (THz) generation in the frequency range of0.1-10 THz has been a fast-developing research area ever since the beginning of the THz boom two decades ago,enabling new technological breakthroughs in spectroscopy,communication,imaging,etc.By using optical (laser) pumping methods with near-or mid-infrared (IR) lasers,flexible and practical THz sources covering the whole THz range can be realized to overcome the shortage of electronic THz sources and now they are playing important roles in THz science and technology.This paper overviews various optically pumped THz sources,including femtosecond laser based ultrafast broadband THz generation,monochromatic widely tunable THz generation,single-mode on-chip THz source from photomixing,and the traditional powerful THz gas lasers.Full descriptions from basic principles to the latest progress are presented and their advantages and disadvantages are discussed as well.It is expected that this review gives a comprehensive reference to researchers in this area and additionally helps newcomers to quickly gain understanding of optically pumped THz sources.

Nonlinear optics in germanium mid-infrared fiber material: Detuning oscillations in femtosecond mid-infrared spectroscopy

Directory of Open Access Journals (Sweden)

M. Ordu

2017-09-01

Full Text Available Germanium optical fibers hold great promise in extending semiconductor photonics into the fundamentally important mid-infrared region of the electromagnetic spectrum. The demonstration of nonlinear response in fabricated Ge fiber samples is a key step in the development of mid-infrared fiber materials. Here we report the observation of detuning oscillations in a germanium fiber in the mid-infrared region using femtosecond dispersed pump-probe spectroscopy. Detuning oscillations are observed in the frequency-resolved response when mid-infrared pump and probe pulses are overlapped in a fiber segment. The oscillations arise from the nonlinear frequency resolved nonlinear (χ(3 response in the germanium semiconductor. Our work represents the first observation of coherent oscillations in the emerging field of germanium mid-infrared fiber optics.

The Far-Infrared Surveyor (FIS) for AKARI

NARCIS (Netherlands)

Kawada, Mitsunobu; Baba, Hajime; Barthel, Peter D.; Clements, David; Cohen, Martin; Doi, Yasuo; Figueredo, Elysandra; Fujiwara, Mikio; Goto, Tomotsugu; Hasegawa, Sunao; Hibi, Yasunori; Hirao, Takanori; Hiromoto, Norihisa; Jeong, Woong-Seob; Kaneda, Hidehiro; Kawai, Toshihide; Kawamura, Akiko; Kester, Do; Kii, Tsuneo; Kobayashi, Hisato; Kwon, Suk Minn; Lee, Hyung Mok; Makiuti, Sin'itirou; Matsuo, Hiroshi; Matsuura, Shuji; Mueller, Thomas G.; Murakami, Noriko; Nagata, Hirohisa; Nakagawa, Takao; Narita, Masanao; Noda, Manabu; Oh, Sang Hoon; Okada, Yoko; Okuda, Haruyuki; Oliver, Sebastian; Ootsubo, Takafumi; Pak, Soojong; Park, Yong-Sun; Pearson, Chris P.; Rowan-Robinson, Michael; Saito, Toshinobu; Salama, Alberto; Sato, Shinji; Savage, Richard S.; Serjeant, Stephen; Shibai, Hiroshi; Shirahata, Mai; Sohn, Jungjoo; Suzuki, Toyoaki; Takagi, Toshinobu; Takahashi, Hidenori; Thomson, Matthew; Usui, Fumihiko; Verdugo, Eva; Watabe, Toyoki; White, Glenn J.; Wang, Lingyu; Yamamura, Issei; Yamauchi, Chisato; Yasuda, Akiko

2007-01-01

The Far-Infrared Surveyor (FIS) is one of two focal-plane instruments on the AKARI satellite. FIS has four photometric bands at 65, 90, 140, and 160 mu m, and uses two kinds of array detectors. The FIS arrays and optics are designed to sweep the sky with high spatial resolution and redundancy. The

High-resolution far-infrared observations of the galactic center

International Nuclear Information System (INIS)

Harvey, P.M.; Campbell, M.F.; Hoffmann, W.F.

1976-01-01

A map at 53 μ with 17'' resolution and three-color observations at 53 μ, 100 μ, and 175 μ with approx.30'' beams of Sgr A are presented. Sagittarius A is resolved into two main sources, one associated with the cluster of strong 10 μ sources and another approx.45'' to the southwest coincident with a weak 10 μ source. The dust temperature peaks near the strong 10 μ sources, but the 100 μ and 175 μ fluxes and the far-infrared optical depth are greatest near the southwest source. The amount of dust required to explain the far-infrared emission is comparable to that observed in absorption in the near-infrared

Dual-channel operation in a synchronously pumped optical parametric oscillator for the generation of broadband mid-infrared coherent light sources.

Science.gov (United States)

Liu, Pei; Wang, Sicong; He, Puyuan; Zhang, Zhaowei

2018-05-01

We report, to the best of our knowledge, a novel approach for generating broadband mid-infrared (mid-IR) light by implementing a dual-channel scheme in a synchronously pumped optical parametric oscillator (SPOPO). Two-channel operation was achieved by inserting a prism pair and two reflection mirrors inside an optical parametric oscillator (OPO) cavity. Pumped by a Yb-fiber laser, the OPO generated an idler wave at ∼3150  nm with a -10  dB bandwidth of ∼13.2  THz, which was twice as much as that of the pump source. This scheme represents a promising technical route to transform conventional SPOPOs into a device capable of generating mid-IR light with very broad instantaneous bandwidth.

Kinetic inductance detectors for far-infrared spectroscopy

International Nuclear Information System (INIS)

Barlis, A.; Aguirre, J.; Stevenson, T.

2016-01-01

The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (at redshift of about 2.5) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation. Here, we describe a detector system suitable for a balloon-borne spectroscopic intensity mapping experiment at far-infrared wavelengths. The system uses lumped-element kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity and low noise levels. KIDs consist of separate capacitive and inductive elements, and use the inductive element as the radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels. - Highlights: • We describe a concept for a balloon-borne telescope for far-IR wavelengths. • Telescope would use high-sensitivity kinetic inductance detectors. • Design considerations and fabrication process for prototype detectors.

Kinetic inductance detectors for far-infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Barlis, A., E-mail: abarlis@physics.upenn.edu [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Aguirre, J. [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Stevenson, T. [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States)

2016-07-11

The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (at redshift of about 2.5) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation. Here, we describe a detector system suitable for a balloon-borne spectroscopic intensity mapping experiment at far-infrared wavelengths. The system uses lumped-element kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity and low noise levels. KIDs consist of separate capacitive and inductive elements, and use the inductive element as the radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels. - Highlights: • We describe a concept for a balloon-borne telescope for far-IR wavelengths. • Telescope would use high-sensitivity kinetic inductance detectors. • Design considerations and fabrication process for prototype detectors.

Observation of galactic far-infrared ray

International Nuclear Information System (INIS)

Maihara, Toshinori; Oda, Naoki; Okuda, Haruyuki; Sugiyama, Takuya; Sakai, Kiyomi.

1978-01-01

Galactic far-infrared was observed to study the spatial distribution of interstellar dust. Far-infrared is emitted by interstellar dust distributing throughout the galactic plane. The observation of far-infrared is very important to study the overall structure of the galaxy, that is the structure of the galactic arm and gas distribution. The balloon experiment was conducted on May 25, 1978. The detector was a germanium bolometer cooled by liquid helium. The size of the detector is 1.6 mm in diameter. The geometrical factor was 4 x 10 3 cm 2 sr. The result showed that the longitude distribution of far-infrared at 150 μm correlated with H 166 α recombination line. This indicates that the observed far-infrared is emitted by interstellar dust heated by photons of Lyman continuum. (Yoshimori, M.)

Spectrophotometry in the far infrared. Optical and Hertzian processes

International Nuclear Information System (INIS)

Coste, Andre

1968-01-01

After a general study of problems related to instrumental spectroscopy in the far infrared, this research thesis examines the theory and technique of construction of slit spectrometers. The author then studied the possibilities to increase brightness and resolution using Fabry-Perot interferometers, and the Fourier transform interferential spectrometry, and finally addressed methods used with micro-waves

A far-infrared Michelson interferometer for tokamak electron density measurements using computer-generated reference fringes

International Nuclear Information System (INIS)

Krug, P.A.; Stimson, P.A.; Falconer, I.S.

1986-01-01

A simple far-infrared interferometer which uses the 394 μm laser line from optically-pumped formic acid vapour to measure tokamak electron density is described. This interferometer is unusual in requiring only one detector and a single probing beam since reference fringes during the plasma shot are obtained by computer interpolation between the fringes observed immediately before and after the shot. Electron density has been measured with a phase resolution corresponding to + - 1/20 wavelength fringe shift, which is equivalent to a central density resolution of + - 0.1 x 10 19 m -3 for an assumed parabolic density distribution in a plasma of diameter of 0.2 m, and with a time resolution of 0.2 ms. (author)

A dual far-infrared laser diagnostic of magnetized plasmas

International Nuclear Information System (INIS)

Darrow, D.S.; Park, H.K.

1988-02-01

A dual far-infrared laser has been constructed and its properties have been exploited to probe tokamak-like discharges in the CDX toroidal device. Thermal variation of the difference frequency between the two far-infrared cavities is slow, though the cavities lack thermal stabilization, simply because their assembly on the same chassis exposes them to virtually identical temperature changes. The optical arrangement beyond the laser permits conversion within minutes between interferometry and density fluctuation observation, and within an hour between different operating wavelengths. Line-average densities of 2 /times/ 10 13 cm -3 and coherent fluctuations in the neighborhood of 20 kHz have been measured with this diagnostic. 15 refs., 5 figs., 2 tabs

A composite plot of far-infrared versus radio luminosity, and the origin of far-infrared luminosity in quasars

International Nuclear Information System (INIS)

Sopp, H.M.; Alexander, P.

1991-01-01

We have constructed a composite plot of far-infrared versus radioluminosity for late-type galaxies, Seyferts, quasars and radio galaxies. The most striking result is that the radio and far-infrared luminosities of radio-quiet quasars are correlated and follow the same correlation as normal star-forming galaxies and ultra-luminous infrared galaxies, whereas the radio-loud quasars have luminosities in both bands similar to those of radio galaxies. We conclude that the far-infrared emission from radio-quiet quasars is from star-forming host galaxies and not from active galactic nuclei. The far-infrared radio plot may be a powerful discriminator between host galaxy type. (author)

Developing Wide-Field Spatio-Spectral Interferometry for Far-Infrared Space Applications

Science.gov (United States)

Leisawitz, David; Bolcar, Matthew R.; Lyon, Richard G.; Maher, Stephen F.; Memarsadeghi, Nargess; Rinehart, Stephen A.; Sinukoff, Evan J.

2012-01-01

Interferometry is an affordable way to bring the benefits of high resolution to space far-IR astrophysics. We summarize an ongoing effort to develop and learn the practical limitations of an interferometric technique that will enable the acquisition of high-resolution far-IR integral field spectroscopic data with a single instrument in a future space-based interferometer. This technique was central to the Space Infrared Interferometric Telescope (SPIRIT) and Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) space mission design concepts, and it will first be used on the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII). Our experimental approach combines data from a laboratory optical interferometer (the Wide-field Imaging Interferometry Testbed, WIIT), computational optical system modeling, and spatio-spectral synthesis algorithm development. We summarize recent experimental results and future plans.

Generation of tunable coherent far-infrared radiation using atomic Rydberg states

International Nuclear Information System (INIS)

Bookless, W.

1980-12-01

A source of tunable far-infrared radiation has been constructed. The system has been operated at 91.6 cm -1 with a demonstrated tunability of .63 cm -1 . The system is based on a Rydberg state transition in optically pumped potassium vapor. The transition energy is tuned by the application of an electric field to the excited vapor. The transition wavelength and the shifted wavelength were detected and measured by the use of a Michelson interferometer and a liquid helium cooled Ga:Ge bolometer and the data was reduced using Fast Fourier transform techniques. Extensive spectroscopy was done on the potassium vapor to elucidate the depopulation paths and rates of the excited levels. Both theoretical and experimental results are presented to support the conclusions of the research effort. Additionally, possible alternative approaches to the population of the excited state are explored and recommendations are made for the future development of this source as well as the potential uses of it in molecular spectroscopy

Far infrared photoconductors

International Nuclear Information System (INIS)

Leotin, J.; Meny, C.

1990-01-01

This paper presents the development of far infrared photoconductors for the focal plane of a spaceborne instrument named SAFIRE. SAFIRE (Spectroscopy of the Atmosphere using Far-Infrared Emission) belongs to the EOS program (Earth Observing System) and is now in the definition phase. It is a joint effort by scientists from the United States, Great Britain, Italy and France for a new generation of atmosphere sensor. The overall goal of the SAFIRE experiment is to improve the understanding of the ozone distribution in the middle atmosphere by conducting global scale measurements of the important chemical, radiative and dynamical processes which influence its changes. This will be accomplished by the measurement of the far infrared thermal limb emission in seven spectral channels covering the range 80 to 400 cm -1 with a maximum resolution of 0.004 cm -1 . For example key gases like OH, O, HO 2 , N 2 O 5 will be probed for the first time. Achievement of the required detector sensitivity in the far-infrared imposes the choice of photoconductive detectors operating at liquid helium temperatures. Germanium doped with gallium is selected for six channels whereas germanium doped with beryllium is suitable for the N 2 O 5 channel. Both photoconductors Ge:Ga and Ge:Be benefit from a well established material technology. A better wavelength coverage of channel 1 is achieved by applying a small uniaxial stress of the order of 0.1 GPa on the Ge:Ga photoconductors. The channel 6B wavelength coverage could be improved by using zinc-doped-germanium (Ge:Zn) or, much better, by using a Blocked Impurity band silicon detector doped with antimony (BIB Si:Sb). The later is developed as an optional basis

Determination of thicknesses and temperatures of crystalline silicon wafers from optical measurements in the far infrared region

Science.gov (United States)

Franta, Daniel; Franta, Pavel; Vohánka, Jiří; Čermák, Martin; Ohlídal, Ivan

2018-05-01

Optical measurements of transmittance in the far infrared region performed on crystalline silicon wafers exhibit partially coherent interference effects appropriate for the determination of thicknesses of the wafers. The knowledge of accurate spectral and temperature dependencies of the optical constants of crystalline silicon in this spectral region is crucial for the determination of its thickness and vice versa. The recently published temperature dependent dispersion model of crystalline silicon is suitable for this purpose. Because the linear thermal expansion of crystalline silicon is known, the temperatures of the wafers can be determined with high precision from the evolution of the interference patterns at elevated temperatures.

Using far-infrared limb brightening to probe isolated dark globules

International Nuclear Information System (INIS)

Leung, C.M.; O'brien, E.V.; Dubisch, R.

1989-01-01

The problem of radiation transport in dark globules with or without internal heat source, immersed in an isotropic incident interstellar radiation field, is solved. The phenomenon of infrared limb brightening, its dependence on cloud properties, and its observational implications are addressed. Numerical results regarding the dependence of limb brightening on total cloud opacity, luminosity of internal heat source, grain type, dust density distribution, and wavelength of emitted radiation are discussed. Observational implications concerning the use of limb brightening to place an upper limit on the luminosity of an embedded protostar and to determine the grain emissivity law in the far-infrared are examined. For sufficiently large optical depth, the limb-brightening ratio (LBR) is found to be related to the optical depth by a power-law relation in the 140-300 micron wavelength range, where thermal emission from grains peaks. By observing the LBR in this range, this power-law relationship can be exploited to determine the emissivity law of the dust grain in the far-infrared. Both the LBR and the longest wavelength for which limb brightening still occurs are related linearly to the luminosity of the central source. 37 references

Optically pumped atoms

CERN Document Server

Happer, William; Walker, Thad

2010-01-01

Covering the most important knowledge on optical pumping of atoms, this ready reference is backed by numerous examples of modelling computation for optical pumped systems. The authors show for the first time that modern scientific computing software makes it practical to analyze the full, multilevel system of optically pumped atoms. To make the discussion less abstract, the authors have illustrated key points with sections of MATLAB codes. To make most effective use of contemporary mathematical software, it is especially useful to analyze optical pumping situations in the Liouville spa

Biological activities caused by far-infrared radiation

Science.gov (United States)

Inoué, Shojiro; Kabaya, Morihiro

1989-09-01

Contrary to previous presumption, accumulated evidence indicates that far-infrared rays are biologically active. A small ceramic disk that emist far-infrared rays (4 16 μm) has commonly been applied to a local spot or a whole part of the body for exposure. Pioneering attempts to experimentally analyze an effect of acute and chronic radiation of far-infrared rays on living organisms have detected a growth-promoting effect in growing rats, a sleep-modulatory effect in freely behaving rats and an insomiac patient, and a blood circulation-enhancing effect in human skin. Question-paires to 542 users of far-infrared radiator disks embedded in bedelothes revealed that the majority of the users subjectively evaluated an improvement of their health. These effects on living organisms appear to be non-specifically triggered by an exposure to far-infrared rays, which eventually induce an increase in temperature of the body tissues or, more basically, an elevated motility of body fluids due to decrease in size of water clusters.

Optically Pumped Far Infrared Molecular Lasers.

Science.gov (United States)

1980-04-01

and 4 were reported by Fetterman , et al. and Gullberg, et al.3 An additional FIR transition (i.e., G:sR(5,4) has been reported,5 but is not shown in...attempt has been made to frequency stabilize the experiment. Recently, Fetterman , et al. 11 performed "real-ti adctral analysis for FIR laser pulses...wave device known 4 as a Reflective Array Compressor (RAC) was developed for just this sort of problem in the radar community. Recently, Fetterman , et al

Optical Properties of Natural Minerals in the Far-Infrared

Science.gov (United States)

Long, Larry Lavern

The reflectivity of natural mineral powders were measured in the far infrared. The complex indices of refraction were then determined by Kramers-Kronig analysis or dispersive analysis. The samples were constructed by pressing the powdered sample into a 13 mm diameter pellet. A few of the samples that were measured were kaolin, illite, and montmorillonite, clay samples that could not be obtained in large single crystals. For calcite and gypsum crystals a comparison between the single crystal measurements and powder measurements was done to determine the effect of sample preparation on the measured spectra.

Multi-quantum excitation in optically pumped alkali atom: rare gas mixtures

Science.gov (United States)

Galbally-Kinney, K. L.; Rawlins, W. T.; Davis, S. J.

2014-03-01

Diode-pumped alkali laser (DPAL) technology offers a means of achieving high-energy gas laser output through optical pumping of the D-lines of Cs, Rb, and K. The exciplex effect, based on weak attractive forces between alkali atoms and polarizable rare gas atoms (Ar, Kr, Xe), provides an alternative approach via broadband excitation of exciplex precursors (XPAL). In XPAL configurations, we have observed multi-quantum excitation within the alkali manifolds which result in infrared emission lines between 1 and 4 μm. The observed excited states include the 42FJ states of both Cs and Rb, which are well above the two-photon energy of the excitation laser in each case. We have observed fluorescence from multi-quantum states for excitation wavelengths throughout the exciplex absorption bands of Cs-Ar, Cs-Kr, and Cs-Xe. The intensity scaling is roughly first-order or less in both pump power and alkali concentration, suggesting a collisional energy pooling excitation mechanism. Collisional up-pumping appears to present a parasitic loss term for optically pumped atomic systems at high intensities, however there may also be excitation of other lasing transitions at infrared wavelengths.

Radio continuum, far infrared and star formation

International Nuclear Information System (INIS)

Wielebinski, R.; Wunderlich, E.; Klein, U.; Hummel, E.

1987-01-01

A very tight correlation was found between the radio emission and the far infrared emission from galaxies. This has been found for various samples of galaxies and is explained in terms of recent star formation. The tight correlation would imply that the total radio emission is a good tracer of star formation. The correlation between the radio power at 5 GHz and the far infrared luminosity is shown. The galaxies are of various morphological types and were selected from the various IRAS circulars, hence the sample is an infrared selected sample. The far infrared luminosities were corrected for the dust temperature. This is significant because it decreases the dispersion in the correlation

Vibration mitigation in J-TEXT far-infrared diagnostic systems

International Nuclear Information System (INIS)

Li, Q.; Chen, J.; Zhuang, G.; Wang, Z. J.; Gao, L.; Chen, W.

2012-01-01

Optical structure stability is an important issue for far-infrared (FIR) phase measurements. To ensure good signal quality, influence of vibration should be minimized. Mechanical amelioration and optical optimization can be taken in turn to decrease vibration's influence and ensure acceptable measurement. J-TEXT (Joint Texal Experiment Tokamak, formerly TEXT-U) has two FIR diagnostic systems: a HCN interferometer system for electron density measurement and a three-wave polarimeter-interferometer system (POLARIS) for electron density and Faraday effect measurements. All use phase detection techniques. HCN interferometer system has almost eliminated the influence of vibration after mechanical amelioration and optical optimization. POLARIS also obtained first experimental results after mechanical stability improvements and is expected to further reduce vibration's influence on Faraday angle to 0.1° after optical optimization.

Far infrared properties of PbTe doped with cerium

International Nuclear Information System (INIS)

Nikolic, P.M.; Koenig, W.; Vujatovic, S.S.; Blagojevic, V.; Lukovic, D.; Savic, S.; Radulovic, K.; Urosevic, D.; Nikolic, M.V.

2007-01-01

Single crystal samples of lead telluride doped with cerium were made using the Bridgman method. Far infrared reflectivity spectra in the temperature range from 10 to 300 K are presented. The experimental data were numerically analyzed using a fitting procedure based on the plasmon-phonon interaction model and optical parameters were determined. Two additional local modes were observed at about 138 and 337 cm -1 . The origin of these local vibrational impurity modes was discussed

Feasibility of the optical imaging of thrombus formation in a rotary blood pump by near-infrared light.

Science.gov (United States)

Sakota, Daisuke; Murashige, Tomotaka; Kosaka, Ryo; Nishida, Masahiro; Maruyama, Osamu

2014-09-01

Blood coagulation is one of the primary concerns when using mechanical circulatory support devices such as blood pumps. Noninvasive detection and imaging of thrombus formation is useful not only for the development of more hemocompatible devices but also for the management of blood coagulation to avoid risk of infarction. The objective of this study is to investigate the use of near-infrared light for imaging of thrombus formation in a rotary blood pump. The optical properties of a thrombus at wavelengths ranging from 600 to 750 nm were analyzed using a hyperspectral imaging (HSI) system. A specially designed hydrodynamically levitated centrifugal blood pump with a visible bottom area was used. In vitro antithrombogenic testing was conducted five times with the pump using bovine whole blood in which the activated blood clotting time was adjusted to 200 s prior to the experiment. Two halogen lights were used for the light sources. The forward scattering through the pump and backward scattering on the pump bottom area were imaged using the HSI system. HSI showed an increase in forward scattering at wavelengths ranging from 670 to 750 nm in the location of thrombus formation. The time at which the thrombus began to form in the impeller rotating at 2780 rpm could be detected. The spectral difference between the whole blood and the thrombus was utilized to image thrombus formation. The results indicate the feasibility of dynamically detecting and imaging thrombus formation in a rotary blood pump. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Far-infrared spectroscopy of HII regions

International Nuclear Information System (INIS)

Emery, R.J.; Kessler, M.F.

1984-01-01

Interest has developed rapidly in the astrophysics associated with far-infrared line emission from ionised regions, following the development of spectroscopic instruments and observing facilities appropriate to those wavelengths. Far-infrared observations and their interpretation are now at the stage where the need for specific developments in theoretical and laboratory work have been identified. The need is also apparent for the development of models dealing with more realistic astrophysical situations. (Auth.)

Generating Efficient Femtosecond Mid-infrared Pulse by Single Near-infrared Pump Wavelength in Bulk Nonlinear Crystal Without Phase-matching

DEFF Research Database (Denmark)

Zhou, Binbin; Guo, Hairun; Bache, Morten

2014-01-01

We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8-2.92 μm are generated using the single pump wavelengths from 1.25-1.45 μm. © 2014 Optical Society of America...

Far infrared properties of PbTe doped with cerium

Energy Technology Data Exchange (ETDEWEB)

Nikolic, P.M. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia)]. E-mail: nikolic@sanu.ac.yu; Koenig, W. [Max Planck Institut fuer Festkoerperforschung, Heisenbergstrasse 1, 7000 Stuttgart 80 (Germany); Vujatovic, S.S. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Blagojevic, V. [Faculty of Electronic Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, 11000 Belgrade (Serbia); Lukovic, D. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Savic, S. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Radulovic, K. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Urosevic, D. [Mathematical Institute SASA, Knez Mihailova 35/I, 11000 Belgrade (Serbia); Nikolic, M.V. [Center for Multidisciplinary Studies of the University of Belgrade, Kneza Viseslava 1, Belgrade (Serbia)

2007-05-16

Single crystal samples of lead telluride doped with cerium were made using the Bridgman method. Far infrared reflectivity spectra in the temperature range from 10 to 300 K are presented. The experimental data were numerically analyzed using a fitting procedure based on the plasmon-phonon interaction model and optical parameters were determined. Two additional local modes were observed at about 138 and 337 cm{sup -1}. The origin of these local vibrational impurity modes was discussed.

Far-infrared contraband-detection-system development for personnel-search applications

International Nuclear Information System (INIS)

Schellenbaum, R.L.

1982-09-01

Experiments have been conducted toward the development of an active near-millimeter-wave, far infrared, personnel search system for the detection of contraband. These experiments employed a microwave hybrid tee interferometer/radiometer scanning system and quasi-optical techniques at 3.3-mm wavelength to illuminate and detect the reflection from target objects against a human body background. Clothing and other common concealing materials are transport at this wavelength. Retroreflector arrays, in conjunction with a Gunn diode radiation source, were investigated to provide all-angle illumination and detection of specular reflections from unaligned and irregular-shaped objects. Results indicate that, under highly controlled search conditions, metal objects greater than or equal to 25 cm 2 can be detected in an enclosure lined with retroreflectors. Further development is required to produce a practical personnel search system. The investigation and feasibility of alternate far infrared search techniques are presented. 23 figures, 2 tables

Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches.

OpenAIRE

Boone, F.; Schaerer, D.; Pelló, R.; Lutz, D.; Weiss, A.; Egami, E.; Smail, I.; Rex, M.; Rawle, T.; Ivison, R.; Laporte, N.; Beelen, A.; Combes, F.; Blain, A.W.; Richard, J.

2011-01-01

The spectral energy distributions (SED) of dusty galaxies at intermediate redshift may look similar to very high-redshift galaxies in the optical/near infrared (NIR) domain. This can lead to the contamination of high-redshift galaxy searches based on broad-band optical/NIR photometry by lower redshift dusty galaxies because both kind of galaxies cannot be distinguished. The contamination rate could be as high as 50%. This work shows how the far-infrared (FIR) domain can help to recognize like...

Coherent atomic and molecular spectroscopy in the far infrared

International Nuclear Information System (INIS)

Inguscio, M.

1988-01-01

Recent advances in far infrared spectroscopy of atoms (fine structure transitions) and molecules (rotational transitions) are reviewed. Results obtained by means of Laser Magnetic Resonance, using fixed frequency lasers, and Tunable Far Infrared spectrometers are illustrated. The importance of far infrared spectroscopy for several fields, including astrophysics, atmospheric physics, atomic structure and metology, is discussed. (orig.)

Design and analysis of optically pumped submillimeter waveguide maser amplifiers and oscillators

Science.gov (United States)

Galantowicz, T. A.

1975-01-01

The design and experimental measurements are described of an optically pumped far-infrared (FIR) waveguide maser; preliminary measurements on a FIR waveguide amplifier are presented. The FIR maser was found to operate satisfactorily in a chopped CW mode using either methanol (CH3OH) or acetonitrile (CH3CN) as the active molecule. Two other gases, difluoroethane and difluoroethylene, produced an unstable output with high threshold and low output power when operated in the chopped CW mode. Experimental measurements include FIR output versus cavity length, output beam pattern, output power versus pressure, and input power. The FIR output was the input to an amplifier which was constructed similar to the oscillator. An increase of 10% in output power was noted on the 118.8 microns line of methanol.

Development of a real-time and quantitative thrombus sensor for an extracorporeal centrifugal blood pump by near-infrared light.

Science.gov (United States)

Sakota, Daisuke; Fujiwara, Tatsuki; Ohuchi, Katsuhiro; Kuwana, Katsuyuki; Yamazaki, Hiroyuki; Kosaka, Ryo; Nishida, Masahiro; Mizuno, Tomohiro; Arai, Hirokuni; Maruyama, Osamu

2018-01-01

We developed an optical thrombus sensor for a monopivot extracorporeal centrifugal blood pump. In this study, we investigated its quantitative performance for thrombus detection in acute animal experiments of left ventricular assist using the pump on pathogen-free pigs. Optical fibers were set in the driver unit of the pump. The incident light at the near-infrared wavelength of 810 nm was aimed at the pivot bearing, and the resulting scattered light was guided to the optical fibers. The detected signal was analyzed to obtain the thrombus formation level. As a result, real-time and quantitative monitoring of the thrombus surface area on the pivot bearing was achieved with an accuracy of 3.6 ± 2.3 mm 2 . In addition, the sensing method using the near-infrared light was not influenced by changes in the oxygen saturation and the hematocrit. It is expected that the developed sensor will be useful for optimal anticoagulation management for long-term extracorporeal circulation therapies.

Far-infrared spectroscopy of neutral interstellar clouds

International Nuclear Information System (INIS)

Watson, D.M.

1984-01-01

A summary is presented of airborne observations of the far-infrared fine structure lines of neutral atomic oxygen and singly-ionized carbon, and of the far-infrared rotational lines of CO, OH, NH 3 and HD, together with a brief description of the analysis and interpretation of the spectra. The 'state of the art' in instrument performance and the prospects for improved sensitivity and resolution are also surveyed. (Auth.)

Josephson effect far-infrared detector

International Nuclear Information System (INIS)

Shapiro, S.

1971-01-01

Four Josephson effect schemes for detection of far-infrared radiation are reviewed: Video broad-band detection, regenerative detection, conventional mixing for monochromatic signals, and self-mixing or frequency conversion. (U.S.)

Nuclear radiation detected optical pumping of neutron deficient Hg isotopes

International Nuclear Information System (INIS)

Bonn, J.

1975-01-01

The extension of the Nuclear Radiation Detected Optical Pumping method to mass-separated samples of isotopes far off stability is presented for a series of light Hg isotopes produced at the ISOLDE facility at CERN. The isotope under investigation is transferred by an automatic transfer system into the optical pumping apparatus. Zeeman scanning of an isotopically pure Hg spectral lamp is used to reach energetic coincidence with the hyperfine structure components of the 6s 2 1 S 0 -6s6p 3 P 1 (lambda = 2537 A) resonance line of the investigated isotope and the Hg lamp. The orientation build up by optical pumping is monitored via the asymmetry or anisotropy of the nuclear radiation. Nuclear spins, magnetic moments, electric quadrupole moments and isotopic shift are obtained for 181 Hg- 191 Hg using the β-asymmetry as detector. The extension of the method using the γ-anisotropy is discussed and measurements on 193 Hg are presented. (orig./HK)

Continuous-wave infrared optical gain and amplified spontaneous emission at ultralow threshold by colloidal HgTe quantum dots.

Science.gov (United States)

Geiregat, Pieter; Houtepen, Arjan J; Sagar, Laxmi Kishore; Infante, Ivan; Zapata, Felipe; Grigel, Valeriia; Allan, Guy; Delerue, Christophe; Van Thourhout, Dries; Hens, Zeger

2018-01-01

Colloidal quantum dots (QDs) raise more and more interest as solution-processable and tunable optical gain materials. However, especially for infrared active QDs, optical gain remains inefficient. Since stimulated emission involves multifold degenerate band-edge states, population inversion can be attained only at high pump power and must compete with efficient multi-exciton recombination. Here, we show that mercury telluride (HgTe) QDs exhibit size-tunable stimulated emission throughout the near-infrared telecom window at thresholds unmatched by any QD studied before. We attribute this unique behaviour to surface-localized states in the bandgap that turn HgTe QDs into 4-level systems. The resulting long-lived population inversion induces amplified spontaneous emission under continuous-wave optical pumping at power levels compatible with solar irradiation and direct current electrical pumping. These results introduce an alternative approach for low-threshold QD-based gain media based on intentional trap states that paves the way for solution-processed infrared QD lasers and amplifiers.

Continuous-wave infrared optical gain and amplified spontaneous emission at ultralow threshold by colloidal HgTe quantum dots

Science.gov (United States)

Geiregat, Pieter; Houtepen, Arjan J.; Sagar, Laxmi Kishore; Infante, Ivan; Zapata, Felipe; Grigel, Valeriia; Allan, Guy; Delerue, Christophe; van Thourhout, Dries; Hens, Zeger

2018-01-01

Colloidal quantum dots (QDs) raise more and more interest as solution-processable and tunable optical gain materials. However, especially for infrared active QDs, optical gain remains inefficient. Since stimulated emission involves multifold degenerate band-edge states, population inversion can be attained only at high pump power and must compete with efficient multi-exciton recombination. Here, we show that mercury telluride (HgTe) QDs exhibit size-tunable stimulated emission throughout the near-infrared telecom window at thresholds unmatched by any QD studied before. We attribute this unique behaviour to surface-localized states in the bandgap that turn HgTe QDs into 4-level systems. The resulting long-lived population inversion induces amplified spontaneous emission under continuous-wave optical pumping at power levels compatible with solar irradiation and direct current electrical pumping. These results introduce an alternative approach for low-threshold QD-based gain media based on intentional trap states that paves the way for solution-processed infrared QD lasers and amplifiers.

Ultrafast optical pump terahertz-probe spectroscopy of strongly correlated electron materials

International Nuclear Information System (INIS)

Averitt, R.D.; Taylor, Antoinette J.; Thorsmolle, V.K.; Jia, Quanxi; Lobad, A.I.; Trugman, S.A.

2001-01-01

We have used optical-pump far-infrared probe spectroscopy to probe the low energy electron dynamics of high temperature superconductors and colossal magnetoresistance manganites. For the superconductor YBa2Cu3O7, picosecond conductivity measurements probe the interplay between Cooper-pairs and quasiparticles. In optimally doped films, the recovery time for long-range phase-coherent pairing increases from ∼1.5 ps at 4K to ∼3.5 ps near Tc, consistent with the closing of the superconducting gap. For underdoped films, the measured recovery time is temperature independent (3.5 ps) in accordance with the presence of a pseudogap. Ultrafast picosecond measurements of optically induced changes in the absolute conductivity of La0:7M0:3MnO3 thin films (M = Ca, Sr) from 10K to ∼0.9Tc reveal a two-component relaxation. A fast, ∼2 ps, conductivity decrease arises from optically induced modification of the effective phonon temperature. The slower component, related to spin-lattice relaxation, has a lifetime that increases upon approaching Tc from below in accordance with an increasing spin specific heat. Our results indicate that for T<< Tc, the conductivity is determined by incoherent phonons while spin fluctuations dominate near Tc.

Far-infrared observations of Large Magellanic Cloud H II regions

International Nuclear Information System (INIS)

Werner, M.W.; Becklin, E.E.; Gatley, I.; Ellis, M.J.; Hyland, A.R.; Robinson, G.; Thomas, J.A.

1978-01-01

Far-infrared emission has been measured from four Large Magellanic Cloud H II regions: the 30 Doradus nebula, MC75, MC76 and MC77. The far-infrared radiation is thermal emission from dust heated by starlight. The results show that the LMC H II regions, like H II regions in the Galaxy, have far-infrared luminosities comparable to the total luminosity of their exciting stars. (author)

Production of polarized negative deuterium ion beam with dual optical pumping in KEK

Energy Technology Data Exchange (ETDEWEB)

Kinsho, M.; Ikegami, K.; Takagi, A. [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan); Mori, Y.

1997-02-01

To obtain highly nuclear-spin vector polarized negative deuterium ion beam, a dual optically pumped polarized negative deuterium ion source has been developed at KEK. It is possible to select a pure nuclear-spin state with this scheme, and negative deuterium ion beam with 100% nuclear-spin vector polarization can be produced in principle. We have obtained about 70% of nuclear-spin vector polarized negative deuterium ion beam so far. This result may open up a new possibilities for the optically pumped polarized ion source. (author)

Conceptual thermal design and analysis of a far-infrared/mid-infrared remote sensing instrument

Science.gov (United States)

Roettker, William A.

1992-07-01

This paper presents the conceptual thermal design and analysis results for the Spectroscopy of the Atmosphere using Far-Infrared Emission (SAFIRE) instrument. SAFIRE has been proposed for Mission to Planet Earth to study ozone chemistry in the middle atmosphere using remote sensing of the atmosphere in the far-infrared (21-87 microns) and mid-infrared (9-16 microns) spectra. SAFIRE requires that far-IR detectors be cooled to 3-4 K and mid-IR detectors to 80 K for the expected mission lifetime of five years. A superfluid helium dewar and Stirling-cycle cryocoolers provide the cryogenic temperatures required by the infrared detectors. The proposed instrument thermal design uses passive thermal control techniques to reject 465 watts of waste heat from the instrument.

Progress in far-infrared spectroscopy: Approximately 1890 to 1970

Science.gov (United States)

Mitsuishi, Akiyoshi

2014-03-01

The history of far-infrared spectroscopy from its beginning to around 1970 is reviewed. Before World War II, the size of the community investigating this topic was limited. During this period, in particular before 1925, about 90% of the papers were published by H. Rubens and his co-workers in Germany. One or two researchers from the US joined the Rubens group per year from 1890 to the beginning of 1910. During the next year or two, some researchers joined M. Czerny, who is seen as the successor of Rubens. After World War II, far-infrared techniques progressed further in the US, which did not suffer damage during the war. The advanced techniques of far-infrared grating spectroscopy were transferred from the US (R. A. Oetjen) to Japan (H. Yoshinaga). Yoshinaga and his co-workers expanded the techniques by themselves. This paper describes the historical development of far-infrared spectroscopy before Fourier transform spectroscopy became popular around 1970.

Prediction of the diffuse far-infrared flux from the galactic plane

International Nuclear Information System (INIS)

Fazio, G.G.; Stecker, F.W.

1976-01-01

A basic model and simple numerical relations useful for future far-infrared studies of the Galaxy are presented. Making use of recent CO and other galactic surveys, we then predict the diffuse far-infrared flux distribution from the galactic plane as a function of galactic longitude l for 4degree< or =l< or =90degree and the far-infrared emissivity as a function of galactocentric distance. Future measurements of the galactic far-infrared flux would yield valuable information on the physical properties and distribution of dust and molecular clouds in the Galaxy, particulary the inner region

DISCOVERY OF TIME VARIATION OF THE INTENSITY OF MOLECULAR LINES IN IRC+10216 IN THE SUBMILLIMETER AND FAR-INFRARED DOMAINS

Energy Technology Data Exchange (ETDEWEB)

Cernicharo, J.; Quintana-Lacaci, G.; Agúndez, M.; Velilla-Prieto, L. [Group of Molecular Astrophysics, ICMM, CSIC, C/Sor Juana Inés de La Cruz N3, E-28049 Madrid (Spain); Teyssier, D.; García-Lario, P. [ESA, ESAC, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Daniel, F. [Univ. Grenoble Alpes, IPAG, F-38000 Grenoble (France); Decin, L. [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Guélin, M. [Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406 St-Martin d' Hères (France); Encrenaz, P. [LERMA, Observatoire de Paris, 61 Av. de l' Observatoire, F-75014 Paris (France); De Beck, E. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE 439 92 Onsala (Sweden); Barlow, M. J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Groenewegen, M. A. T. [Koninklijke Sterrenwacht van België, Ringlaan 3, B-1180 Brussels (Belgium); Neufeld, D. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Pearson, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2014-11-20

We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species toward the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the Heterodyne Instrument for the Far-Infrared (HIFI) instrument on board Herschel and with the IRAM30 m telescope. They cover several observing periods spreading over three years. The line intensity variations for molecules produced in the external layers of the envelope most likely result from time variations in the infrared pumping rates. We analyze the main implications this discovery has on the interpretation of molecular line emission in the envelopes of Mira-type stars. Radiative transfer calculations must take into account both the time variability of infrared pumping and the possible variation of the dust and gas temperatures with stellar phase in order to reproduce the observation of molecular lines at different epochs. The effect of gas temperature variations with stellar phase could be particularly important for lines produced in the innermost regions of the envelope. Each layer of the circumstellar envelope sees the stellar light radiation with a different lag time (phase). Our results show that this effect must be included in the models. The submillimeter and far infrared lines of asymptotic giant branch stars can no longer be considered as safe intensity calibrators.

Multichannel far-infrared phase imaging for fusion plasmas

International Nuclear Information System (INIS)

Young, P.E.; Neikirk, D.P.; Tong, P.P.; Rutledge, D.B.; Luhmann, N.C. Jr.

1985-01-01

A 20-channel far-infrared imaging interferometer system has been used to obtain single-shot density profiles in the UCLA Microtor tokamak. This system differs from conventional multichannel interferometers in that the phase distribution produced by the plasma is imaged onto a single, monolithic, integrated microbolometer linear detector array and provides significantly more channels than previous far-infrared interferometers. The system has been demonstrated to provide diffraction-limited phase images of dielectric targets

The far-infrared spectrum of the OH radical

Science.gov (United States)

Brown, J. M.; Schubert, J. E.; Evenson, K. M.; Radford, H. E.

1982-01-01

It is thought likely that the study of spectral lines in the far-infrared might provide at least as much information about the physics and chemistry of the interstellar environment as radioastronomy. However, by comparison with the microwave region, the far-infrared is largely unexplored. There is a pressing need for good laboratory data to aid searches and assignments of spectra from the interstellar clouds and nebulae. Brown et al. (1981) have conducted a study of the laser magnetic resonance (LMR) spectrum of the OH radical in its ground state at far-infrared wavelengths. The present investigation is concerned with the computation of the frequencies of individual hyperfine transitions involving all rotational levels up to J = 4 1/2. The results of the calculation are presented in a table. The results are summarized in a diagram which shows the low-lying energy levels of OH. The frequencies of transitions between levels studied directly in the LMR spectrum are quite reliable.

Drying characteristics of rough rice by far-infrared radiation heating

International Nuclear Information System (INIS)

Matsuoka, T.

1990-01-01

The relationship between the heat radiation characteristics of a far-infrared radiation heater and the drying characteristics of rough rice was investigated to determine the basic data required for utilization of far-infrared rays for drying rough rice. Results of investigations are discussed in detail

Generation of broadly tunable picosecond mid-infrared laser and sensitive detection of a mid-infrared signal by parametric frequency up-conversion in MgO:LiNbO3 optical parametric amplifiers

International Nuclear Information System (INIS)

Zhang Qiu-Lin; Zhang Jing; Qiu Kang-Sheng; Zhang Dong-Xiang; Feng Bao-Hua; Zhang Jing-Yuan

2012-01-01

Picosecond optical parametric generation and amplification in the near-infrared region within 1.361–1.656 μm and the mid-infrared region within 2.976–4.875 μm is constructed on the basis of bulk MgO:LiNbO 3 crystals pumped at 1.064 μm. The maximum pulse energy reaches 1.3 mJ at 1.464 μm and 0.47 mJ at 3.894 μm, corresponding to a pump-to-idler photon conversion efficiency of 25%. By seeding the hard-to-measure mid-infrared radiation as the idler in the optical parametric amplification and measuring the amplified and frequency up-converted signal in the near-infrared or even visible region, one can measure very week mid-infrared radiation with ordinary detectors, which are insensitive to mid-infrared radiation, with a very high gain. A maximum gain factor of about 7 × 10 7 is achieved at the mid-infrared wavelength of 3.374 μm and the corresponding energy detection limit is as low as about 390 aJ per pulse. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Detection of OH from Comet Halley in the far-infrared

International Nuclear Information System (INIS)

Stacey, G.J.; Lugten, J.B.; Genzel, R.

1986-01-01

The 2 Pi 3/2 (J = 5/2 yields 3/2 + yields - parity) transition of OH was detected in comet Halley at 119.44 microns. The upper limit to the line intensity of the - yields + parity transition is 119.23 microns. The ratio of these lines is consistent with radiative pumping of the rotational levels through absorption of near ultraviolet solar photons which excite the low lying vibrational levels of OH. The far-infrared lines probe the inner regions of the coma where OH is produced through photodissociation of a parent molecule (presumably H 2 O). Hence, these lines complement the 18 cm radio measurements which are sensitive to the outer regions of the comet coma. The OH production rate is highly model dependent but is of the order 2 to 4 times 10 to the 29th power molecules/sec

Far Infrared spectroscopy of proteinogenic and other less common amino acids

Science.gov (United States)

Iglesias-Groth, S.; Cataldo, F.

2018-05-01

Far infrared spectroscopy is a powerful tool complementing the potential of mid infrared spectroscopy for the search and identification of organic molecules in space. The far infrared spectra of a total of 29 amino acids are reported in this study. In addition to the spectra of 20 common proteinogenic amino acids, spectra of a selection of 9 non-proteinogenic amino acids are also reported, including the 2-aminoisobutyric acid or α-aminoisobutyric acid which, with glycine, it is one of the most abundant amino acids found in meteorites. The present database of 29 far infrared spectra may serve as reference in the search for amino acids in space environments, given the new apportunities that JWST offers for mid and far IR spectroscopy.

Plasma diagnostics in infrared and far-infrared range for Heliotron E

International Nuclear Information System (INIS)

Sudo, S.; Zushi, H.; Hondo, K.; Takeiri, Y.; Sano, F.; Besshou, S.; Suematsu, H.; Motojima, O.; Iiyoshi, A.; Muraoka, K.; Tsukishima, T.; Tsunawaki, Y.

1989-01-01

In this paper diagnostics in infrared and far-infrared range for Heliotron E are described: FIR interferometer for measuring electron density profile and ECE for electron temperature profile as routine work, and Fraunhofer diffraction method with a CO 2 laser for density fluctuation and Thomson scattering with a D 2 O laser (λ = 385 μm) for ion temperature, as new methods

Infrared-x-ray pump-probe spectroscopy of the NO molecule

International Nuclear Information System (INIS)

Guimaraes, F.F.; Felicissimo, V.C.; Kimberg, V.; Gel'mukhanov, F.; Aagren, H.; Cesar, A.

2005-01-01

Two color infrared-x-ray pump-probe spectroscopy of the NO molecule is studied theoretically and numerically in order to obtain a deeper insight of the underlying physics and of the potential of this suggested technology. From the theoretical investigation a number of conclusions could be drawn: It is found that the phase of the infrared field strongly influences the trajectory of the nuclear wave packet, and hence, the x-ray spectrum. The trajectory experiences fast oscillations with the vibrational frequency with a modulation due to the anharmonicity of the potential. The dependences of the x-ray spectra on the delay time, the duration, and the shape of the pulses are studied in detail. It is shown that the x-ray spectrum keep memory about the infrared phase after the pump field left the system. This memory effect is sensitive to the time of switching-off the pump field and the Rabi frequency. The phase effect takes maximum value when the duration of the x-ray pulse is one-fourth of the infrared field period, and can be enhanced by a proper control of the duration and intensity of the pump pulse. The manifestation of the phase is different for oriented and disordered molecules and depends strongly on the intensity of the pump radiation

Infrared x-ray pump-probe spectroscopy of the NO molecule

Science.gov (United States)

Guimarães, F. F.; Kimberg, V.; Felicíssimo, V. C.; Gel'Mukhanov, F.; Cesar, A.; Ågren, H.

2005-07-01

Two color infrared x-ray pump-probe spectroscopy of the NO molecule is studied theoretically and numerically in order to obtain a deeper insight of the underlying physics and of the potential of this suggested technology. From the theoretical investigation a number of conclusions could be drawn: It is found that the phase of the infrared field strongly influences the trajectory of the nuclear wave packet, and hence, the x-ray spectrum. The trajectory experiences fast oscillations with the vibrational frequency with a modulation due to the anharmonicity of the potential. The dependences of the x-ray spectra on the delay time, the duration, and the shape of the pulses are studied in detail. It is shown that the x-ray spectrum keep memory about the infrared phase after the pump field left the system. This memory effect is sensitive to the time of switching-off the pump field and the Rabi frequency. The phase effect takes maximum value when the duration of the x-ray pulse is one-fourth of the infrared field period, and can be enhanced by a proper control of the duration and intensity of the pump pulse. The manifestation of the phase is different for oriented and disordered molecules and depends strongly on the intensity of the pump radiation.

Interpreting the cosmic far-infrared background anisotropies using a gas regulator model

Science.gov (United States)

Wu, Hao-Yi; Doré, Olivier; Teyssier, Romain; Serra, Paolo

2018-04-01

Cosmic far-infrared background (CFIRB) is a powerful probe of the history of star formation rate (SFR) and the connection between baryons and dark matter across cosmic time. In this work, we explore to which extent the CFIRB anisotropies can be reproduced by a simple physical framework for galaxy evolution, the gas regulator (bathtub) model. This model is based on continuity equations for gas, stars, and metals, taking into account cosmic gas accretion, star formation, and gas ejection. We model the large-scale galaxy bias and small-scale shot noise self-consistently, and we constrain our model using the CFIRB power spectra measured by Planck. Because of the simplicity of the physical model, the goodness of fit is limited. We compare our model predictions with the observed correlation between CFIRB and gravitational lensing, bolometric infrared luminosity functions, and submillimetre source counts. The strong clustering of CFIRB indicates a large galaxy bias, which corresponds to haloes of mass 1012.5 M⊙ at z = 2, higher than the mass associated with the peak of the star formation efficiency. We also find that the far-infrared luminosities of haloes above 1012 M⊙ are higher than the expectation from the SFR observed in ultraviolet and optical surveys.

Synchrotron-based far-infrared spectroscopy of nickel tungstate

International Nuclear Information System (INIS)

Kalinko, A.; Kuzmin, A.; Roy, P.; Evarestov, R.A.

2016-01-01

Monoclinic antiferromagnetic NiWO 4 was studied by far-infrared (30-600 cm -1 ) absorption spectroscopy in the temperature range of 5-300 K using the synchrotron radiation from SOLEIL source. Two isomorphous CoWO 4 and ZnWO 4 tungstates were investigated for comparison. The phonon contributions in the far-infrared range of tungstates were interpreted using the first-principles spin-polarized linear combination of atomic orbital calculations. No contributions from magnetic excitations were found in NiWO 4 and CoWO 4 below their Neel temperatures down to 5 K.

Optical pumping and xenon NMR

International Nuclear Information System (INIS)

Raftery, M.D.

1991-11-01

Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping 129 Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the 131 Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen

Polarization of far-infrared radiation from molecular clouds

Science.gov (United States)

Novak, G.; Gonatas, D. P.; Hildebrand, R. H.; Platt, S. R.; Dragovan, M.

1989-01-01

The paper reports measurements of the polarization of far-infrared emission from dust in nine molecular clouds. Detections were obtained in Mon R2, in the Kleinmann-Low (KL) nebula in Orion, and in Sgr A. Upper limits were set for six other clouds. A comparison of the 100 micron polarization of KL with that previously measured at 270 microns provides new evidence that the polarization is due to emission from magnetically aligned dust grains. Comparing the results for Orion with measurements at optical wavelengths, it is inferred that the magnetic field direction in the outer parts of the Orion cloud is the same as that in the dense core. This direction is nearly perpendicular to the ridge of molecular emission and is parallel to both the molecular outflow in KL and the axis of rotation of the cloud core. In Mon R2, the field direction which the measurements imply does not agree withthat derived from 0.9-2.2 micron polarimetry. The discrepancy is attributed to scattering in the near-infrared. In Orion and Sgr A, where comparisons are possible, the measurements are in good agreement with 10 micron polarization measurements.

Studies on heat transfer in agricultural products by far-infrared ray

International Nuclear Information System (INIS)

Liu, H.; Mohri, K.; Namba, K.

1998-01-01

Heat is transferred when the object being heated has temperature differences. In this research, the difference of two heating methods (far-infrared ray heating and hot wind heating) was analyzed. To compare their differences, the heat flux was measured by setting a heat flux meter beneath the surface of the object at different depths, then the heat conductivities and heat diffusion rates were analyzed. 1) Compared with hot wind, far-infrared ray heating has more heat flux before reaching a definite depth. 2) The heat conductivity and heat diffusion rates by hot wind heating have specific properties with special objects. The heat conductivity and heat diffusion rate of far-infrared heating are higher than those of hot wind heating. The differences are considered to be caused by far-infrared rays

Far-infrared observations of Sagittarius B2 - reconsideration of source structure

International Nuclear Information System (INIS)

Thronson, H.A. Jr.; Harper, D.A.; Yerkes Observatory, Williams Bay, WI)

1986-01-01

New moderate-angular-resolution far-infrared observations of the Sagittarius B2 star-forming region are presented, discussed, and compared with recent radio molecular and continuum observations of this source. In contrast to previous analyses, its far-infrared spectrum is interpreted as the result of a massive frigid cloud overlying a more-or-less normal infrared source, a natural explanation for the object's previously-noted peculiarities. The characteristics derived for the obscuring cloud are similar to those found for the W51 MAIN object. Both sources have high sub-millimeter surface brightness, a high ratio of sub-millimeter to far-infrared flux, and numerous regions of molecular maser emission. 28 references

Far-infared spectroscopic observations with a Balloon-Borne infrared telescope

International Nuclear Information System (INIS)

Maihara, Toshinori; Takami, Hideki; Mizutani, Kohei

1986-01-01

The first observations of far-infrared celestial objects using the 50-cm Balloon-Borne Infrared Telescope were made in Alice Springs, Australia. Far-infrared spectrophotometric data between 45 and 115 μm were taken for the Orion-KL region, Saturn and a southern H II region RCW 38. The data including high excitation transition lines of CO for Orion-KL, O III lines for RCW 38 and a PH 3 absorption feature of Saturn will be presented. (author)

Optically pumped polarized H- ion source

International Nuclear Information System (INIS)

Anderson, L.W.

1986-01-01

The current status and future prospects for the optically pumped polarized H - ion source are discussed. At the present time H - ion currents of 60 μA and with a polarization of 65% have been produced. The ion current and polarization can be increased significantly if the optically pumped Na charge exchange target density and polarization can be increased. Studies of wall surfaces that permit many bounces before depolarizing the Na electron spin and studies of radiation trapping in optically pumped Na indicate that the Na target density and polarization can be increased substantially. 27 refs., 6 figs., 2 tabs

Science with High Spatial Resolution Far-Infrared Data

Science.gov (United States)

Terebey, Susan (Editor); Mazzarella, Joseph M. (Editor)

1994-01-01

The goal of this workshop was to discuss new science and techniques relevant to high spatial resolution processing of far-infrared data, with particular focus on high resolution processing of IRAS data. Users of the maximum correlation method, maximum entropy, and other resolution enhancement algorithms applicable to far-infrared data gathered at the Infrared Processing and Analysis Center (IPAC) for two days in June 1993 to compare techniques and discuss new results. During a special session on the third day, interested astronomers were introduced to IRAS HIRES processing, which is IPAC's implementation of the maximum correlation method to the IRAS data. Topics discussed during the workshop included: (1) image reconstruction; (2) random noise; (3) imagery; (4) interacting galaxies; (5) spiral galaxies; (6) galactic dust and elliptical galaxies; (7) star formation in Seyfert galaxies; (8) wavelet analysis; and (9) supernova remnants.

Far infrared polarimetry of W51A and M42

Energy Technology Data Exchange (ETDEWEB)

Cudlip, W; Furniss, I; King, K J; Jennings, R E [University Coll., London (UK). Dept. of Physics and Astronomy

1982-09-01

A far infrared polarimeter has been designed for use with a balloon-borne telescope. It uses a rapidly rotating wire grid polarizer with the chopping secondary mirror of the telescope synchronized to the rate of rotation. Observations of M42 using this system show a far infrared polarization of 2.2 +- 0.4 per cent, nearly orthogonal to the near infrared polarization which is usually attributed to dust absorption. Observations of W51A show a much smaller value of the polarization of 0.8 +- 0.5 per cent.

High energy eye-safe and mid-infrared optical parametric oscillator

International Nuclear Information System (INIS)

Liu, J; Liu, Q; Huang, L; Gong, M

2010-01-01

A high energy eye-safe and mid-infrared optical parametric oscillator (OPO) is demonstrated. The nonlinear media is a Y-cut KTA crystal with the length of 20 mm, which is pumped by a Nd:YAG laser. Both eye-safe and mid-infrared laser are output with high energy. When the pump energy is 1 J and the pulse duration is 10 ns, we get 53 mJ idler at 3.632 μm and 151 mJ signal at 1.505 μm. As we know, the idler energy is the highest at the wavelength beyond 3.5 μm and the signal energy is the highest with Y-cut KTA. The results prove that the Y-cut KTA crystal can produce the signal and idler with the energies as high as these in the paper. We have tested the temperature-tuning characters and the coefficient of the idler is 0.26 nm/°C

Laser optical pumping of sodium and lithium atom beams

International Nuclear Information System (INIS)

Cusma, J.T.

1983-01-01

The method of optical pumping with a continuous wave dye laser has been used to produce beams of polarized 23 Na atoms and polarized 6 Li atoms. Optical pumping of a 23 Na atom beam using either a multimode dye laser or a single frequency dye laser with a double passed acousto-optic modulator results in electron spin polarizations of 0.70-0.90 and nuclear spin polarizations of 0.75-0.90. Optical pumping of a 6 Li atom beam using a single frequency dye laser either with an acousto-optic modulator or with Doppler shift pumping results in electron spin polarizations of 0.77-0.95 and nuclear spin polarizations greater than 0.90. The polarization of the atom beam is measured using either the laser induced fluorescence in an intermediate magnetic field or a 6-pole magnet to determine the occupation probabilities of the ground hyperfine sublevels following optical pumping. The results of the laser optical pumping experiments agree with the results of a rate equation analysis of the optical pumping process which predicts that nearly all atoms are transferred into a single sublevel for our values of laser intensity and interaction time. The use of laser optical pumping in a polarized ion source for nuclear scattering experiments is discussed. The laser optical pumping method provides a means of constructing an intense source of polarized Li and Na ions

Far-infrared spectroscopy of lanthanide-based molecular magnetic materials

Energy Technology Data Exchange (ETDEWEB)

Haas, Sabrina

2015-05-13

This thesis demonstrates the applicability of far-infrared spectroscopy for the study of the crystal-field splitting of lanthanides in single-molecular magnetic materials. The far-infrared studies of three different kinds of single-molecular-magnetic materials, a single-ion magnet, a single-chain magnet and an exchange-coupled cluster, yielded a deeper understanding of the crystal-field splitting of the lanthanides in these materials. In addition, our results offered the opportunity to gain a deeper insight into the relaxation processes of these materials.

Recent progress in diode-pumped mid-infrared vibronic solid-state lasers

International Nuclear Information System (INIS)

Sorokina, I.T.; Sorokin, E.; Mirov, S.; Schaffers, K.

2002-01-01

Full text: The last few years were marked by the increased interest of researchers towards the new class of transition-metal doped zinc chalcogenides. In particular Cr:ZnSe attracts a lot of attention as broadly tunable continuous-wave (cw), mode-locked and diode-pumped lasers operating around 2.5 mm. This interest is explained by the absence of other comparable tunable room-temperature laser sources in this spectral region. However, another member of the II-VI compounds family Cr:ZnS, has yet remained barely studied as a laser medium. Recently we demonstrated the first continuous-wave room-temperature tunable over more than 280 nm around 2.3 μm Cr 2+ :ZnS laser, pumped with a Co:MgF2 laser and yielding over 100 mW of output power. The most recent result is the development of a compact tunable over 700 nm continuous-wave room-temperature Cr 2+ :ZnS laser, pumped by the diode-pumped Er-fiber laser at 1.6 μm and generating 0.7 W of the linearly polarized radiation. We also demonstrated direct diode-pumping at 1.6 μm of the Cr 2+ :ZnS. Although the Cr:ZnS exhibited lower (relatively to the Cr:ZnSe) efficiency and output power due to the higher passive losses of the available Cr:ZnS samples, the analysis of the spectroscopic and laser data indicates the high potential of Cr:ZnS for compact broadly tunable mid-infrared systems, as well as for high power applications. The physics of the novel diode-pumped laser systems is highly interesting. It comprises the features of the ion-doped dielectric crystalline lasers and semiconductors. For example, we observe in these media, for the first time to our knowledge, a new nonlinear phenomenon, which is analogous to the opto-optical switching process, where the laser output of the diode-pumped continuous-wave Cr:ZnSe and Cr:ZnS lasers around 2.5 μm is modulated by only a few milliwatt of the visible (470-500 nm) and near-infrared radiation (740-770 nm). We present a physical explanation of the observed effect. Refs. 4 (author)

Properties and Applications of High Emissivity Composite Films Based on Far-Infrared Ceramic Powder.

Science.gov (United States)

Xiong, Yabo; Huang, Shaoyun; Wang, Wenqi; Liu, Xinghai; Li, Houbin

2017-11-29

Polymer matrix composite materials that can emit radiation in the far-infrared region of the spectrum are receiving increasing attention due to their ability to significantly influence biological processes. This study reports on the far-infrared emissivity property of composite films based on far-infrared ceramic powder. X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray powder diffractometry were used to evaluate the physical properties of the ceramic powder. The ceramic powder was found to be rich in aluminum oxide, titanium oxide, and silicon oxide, which demonstrate high far-infrared emissivity. In addition, the micromorphology, mechanical performance, dynamic mechanical properties, and far-infrared emissivity of the composite were analyzed to evaluate their suitability for strawberry storage. The mechanical properties of the far-infrared radiation ceramic (cFIR) composite films were not significantly influenced ( p ≥ 0.05) by the addition of the ceramic powder. However, the dynamic mechanical analysis (DMA) properties of the cFIR composite films, including a reduction in damping and shock absorption performance, were significant influenced by the addition of the ceramic powder. Moreover, the cFIR composite films showed high far-infrared emissivity, which has the capability of prolonging the storage life of strawberries. This research demonstrates that cFIR composite films are promising for future applications.

Airborne observations of far-infrared upwelling radiance in the Arctic

Directory of Open Access Journals (Sweden)

Q. Libois

2016-12-01

Full Text Available The first airborne measurements of the Far-InfraRed Radiometer (FIRR were performed in April 2015 during the panarctic NETCARE campaign. Vertical profiles of spectral upwelling radiance in the range 8–50 µm were measured in clear and cloudy conditions from the surface up to 6 km. The clear sky profiles highlight the strong dependence of radiative fluxes to the temperature inversion typical of the Arctic. Measurements acquired for total column water vapour from 1.5 to 10.5 mm also underline the sensitivity of the far-infrared greenhouse effect to specific humidity. The cloudy cases show that optically thin ice clouds increase the cooling rate of the atmosphere, making them important pieces of the Arctic energy balance. One such cloud exhibited a very complex spatial structure, characterized by large horizontal heterogeneities at the kilometre scale. This emphasizes the difficulty of obtaining representative cloud observations with airborne measurements but also points out how challenging it is to model polar clouds radiative effects. These radiance measurements were successfully compared to simulations, suggesting that state-of-the-art radiative transfer models are suited to study the cold and dry Arctic atmosphere. Although FIRR in situ performances compare well to its laboratory performances, complementary simulations show that upgrading the FIRR radiometric resolution would greatly increase its sensitivity to atmospheric and cloud properties. Improved instrument temperature stability in flight and expected technological progress should help meet this objective. The campaign overall highlights the potential for airborne far-infrared radiometry and constitutes a relevant reference for future similar studies dedicated to the Arctic and for the development of spaceborne instruments.

Performance Analysis Of Single-Pumped And Dual-Pumped Parametric Optical Amplifier

Directory of Open Access Journals (Sweden)

Sandar Myint

2015-06-01

Full Text Available Abstract In this study we present a performance analysis of single-pumped and dual- pumped parametric optical amplifier and present the analysis of gain flatness in dual- pumped Fiber Optical Parametric Amplifier FOPA based on four-wave mixing FWM. Result shows that changing the signal power and pump power give the various gains in FOPA. It is also found out that the parametric gain increase with increase in pump power and decrease in signal power. .Moreover in this paper the phase matching condition in FWM plays a vital role in predicting the gain profile of the FOPAbecause the parametric gain is maximum when the total phase mismatch is zero.In this paper single-pumped parametric amplification over a 50nm gain bandwidth is demonstrated using 500 nm highly nonlinear fiber HNLF and signal achieves about 31dB gain. For dual-pumped parametric amplification signal achieves 26.5dB gains over a 50nm gain bandwidth. Therefore dual-pumped parametric amplifier can provide relatively flat gain over a much wider bandwidth than the single-pumped FOPA.

Far-infrared tangential interferometer/polarimeter design and installation for NSTX-U

Energy Technology Data Exchange (ETDEWEB)

Scott, E. R., E-mail: evrscott@ucdavis.edu [Department of Mechanical and Aerospace Engineering, University of California, Davis, California 95616 (United States); Barchfeld, R. [Department of Applied Science, University of California, Davis, California 95616 (United States); Riemenschneider, P.; Domier, C. W.; Sohrabi, M.; Luhmann, N. C. [Department of Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Muscatello, C. M. [General Atomics, San Diego, California 92121 (United States); Kaita, R.; Ren, Y. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

2016-11-15

The Far-infrared Tangential Interferometer/Polarimeter (FIReTIP) system has been refurbished and is being reinstalled on the National Spherical Torus Experiment—Upgrade (NSTX-U) to supply real-time line-integrated core electron density measurements for use in the NSTX-U plasma control system (PCS) to facilitate real-time density feedback control of the NSTX-U plasma. Inclusion of a visible light heterodyne interferometer in the FIReTIP system allows for real-time vibration compensation due to movement of an internally mounted retroreflector and the FIReTIP front-end optics. Real-time signal correction is achieved through use of a National Instruments CompactRIO field-programmable gate array.

Far-Infrared Absorption of PbSe Nanorods

KAUST Repository

Hyun, Byung-Ryool; Bartnik, A. C.; Koh, Weon-kyu; Agladze, N. I.; Wrubel, J. P.; Sievers, A. J.; Murray, Christopher B.; Wise, Frank W.

2011-01-01

Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical

Energy levels and far-infrared optical absorption of impurity doped semiconductor nanorings: Intense laser and electric fields effects

Energy Technology Data Exchange (ETDEWEB)

Barseghyan, M.G., E-mail: mbarsegh@ysu.am

2016-11-10

Highlights: • The electron-impurity interaction on energy levels in nanoring have been investigated. • The electron-impurity interaction on far-infrared absorption have been investigated. • The energy levels are more stable for higher values of electric field. - Abstract: The effects of electron-impurity interaction on energy levels and far-infrared absorption in semiconductor nanoring under the action of intense laser and lateral electric fields have been investigated. Numerical calculations are performed using exact diagonalization technique. It is found that the electron-impurity interaction and external fields change the energy spectrum dramatically, and also have significant influence on the absorption spectrum. Strong dependence on laser field intensity and electric field of lowest energy levels, also supported by the Coulomb interaction with impurity, is clearly revealed.

Cost Effective, Scalable Optically Pumped Molecular Laser

National Research Council Canada - National Science Library

Nicholson, Jeff

2001-01-01

An optically pumped, For laser was demonstrated operating at 4.0 micrometers. This is the first demonstration of an HBr laser by direct optical pumping of the 0 right arrow 3 vibrational overtone band at 1.34 micrometers...

OH far-infrared emission from low- and intermediate-mass protostars surveyed with Herschel-PACS

DEFF Research Database (Denmark)

Wampfler, Susanne Franziska; Bruderer, S.; Karska, A.

2013-01-01

fluxes nor their broad line widths, strongly suggesting an outflow origin. Slab excitation models indicate that the observed excitation temperature can either be reached if the OH molecules are exposed to a strong far-infrared continuum radiation field or if the gas temperature and density...... are sufficiently high. Using realistic source parameters and radiation fields, it is shown for the case of Ser SMM1 that radiative pumping plays an important role in transitions arising from upper level energies higher than 300 K. The compact emission in the low-mass sources and the required presence of a strong...

Yb-fiber-pumped mid-infrared picosecond optical parametric oscillator tunable across 6.2-6.7 µm

Science.gov (United States)

Kumar, S. Chaitanya; Casals, J. Canals; Parsa, S.; Zawilski, K. T.; Schunemann, P. G.; Ebrahim-Zadeh, M.

2018-06-01

We report a high-average-power picosecond optical parametric oscillator (OPO) tunable in the mid-infrared (mid-IR) based on CdSiP2 synchronously pumped by an Yb-fiber laser at 80 MHz repetition rate. Successful operation of this high-repetition-rate singly-resonant picosecond OPO has been enabled by the improved CSP crystal quality over a long interaction length. The OPO can be tuned across 1264-1284 nm in the near-IR signal and 6205-6724 nm in the mid-IR idler by temperature tuning the CSP crystal over 39-134 °C. By deploying a 5% output coupler for the resonant signal, we have extracted up to 44 mW of average power in the near-IR and up to 95 mW of non-resonant idler power at 6205 nm at 6.3% total conversion efficiency, with > 50 mW over > 55% of the mid-IR tuning range. We have investigated temperature-tuning characteristics of the OPO and compared the data with the theoretical calculations using the recent Sellmeier and thermo-optic coefficients for CdSiP2. The signal pulses from the OPO exhibit a Gaussian pulse duration of 19 ps centered at 1284 nm. We have also studied the output power stability of the OPO, resulting in a passive stability better than 1.9% rms for the near-IR signal and 2.4% rms for the mid-IR idler, measured over > 17 h, with both beams in high spatial quality.

Improved ice particle optical property simulations in the ultraviolet to far-infrared regime

International Nuclear Information System (INIS)

Bi, Lei; Yang, Ping

2017-01-01

To derive the bulk radiative properties of ice clouds, aircraft contrails and snow grains, which are fundamental to atmospheric radiative transfer calculations in downstream applications, it is necessary to accurately simulate the scattering of light by individual ice particles. An ice particle optical property database reported in 2013 (hereafter, TAMUice2013) is updated (hereafter, TAMUice2016) to incorporate recent advances in computation of the optical properties of nonspherical particles. Specifically, we employ the invariant imbedding T-matrix (II-TM) method to compute the optical properties of particles with small to moderate size parameters. Both versions use the Improved Geometric Optics Method (IGOM) to compute the optical properties of large ice crystals, but TAMUice2016 improves the treatment of inhomogeneous waves inside the scattering particles in the case where ice is absorptive such as at infrared wavelengths. To bridge the gap between the extinction efficiencies computed from the II-TM and the IGOM, TAMUice2016 includes spectrally dependent higher order terms of the edge effect in addition to the first order counterpart considered in TAMUice2013. Furthermore, the differences between TAMUice2013 and TAMUice2016 are quantified with respect to the computation of the bulk optical properties of ice clouds. - Highlights: • A previous database of the single-scattering properties of ice crystals is improved. • A combination of the invariant imbedding T-matrix and improved geometric optics methods is used. • The treatment of inhomogeneous waves in an absorptive ice crystal is improved. • Higher order terms of the edge effect are considered in the updated database.

Optically pumped polarized alkali atomic beams and targets

International Nuclear Information System (INIS)

Anderson, L.W.

1984-01-01

The optical pumping of 23 Na and 6 Li atomic beams is discussed. Experiments on the optical pumping of 23 Na atomic beams using either a single mode dye laser followed by a double passed acousto-optic modulator or a multimode dye laser are reported. The optical pumping of a 23 Na vapor target for use in a polarized H - ion source is discussed. Results on the use of viton as a wall coating with a long relaxation time are reported. 31 references, 6 figures, 3 tables

Towards diode-pumped mid-infrared praseodymium-ytterbium-doped fluoride fiber lasers

Science.gov (United States)

Woodward, R. I.; Hudson, D. D.; Jackson, S. D.

2018-02-01

We explore the potential of a new mid-infrared laser transition in praseodymium-doped fluoride fiber for emission around 3.4 μm, which can be conveniently pumped by 0.975 μm diodes via ytterbium sensitizer co-doping. Optimal cavity designs are determined through spectroscopic measurements and numerical modeling, suggesting that practical diode-pumped watt-level mid-infrared fiber sources beyond 3 μm could be achieved.

Combined wide pump tuning and high power of a continuous-wave, singly resonant optical parametric oscillator

NARCIS (Netherlands)

Herpen, M.M.J.W. van; Bisson, S.E.; Ngai, A.K.Y.; Harren, F.J.M.

2004-01-01

A new singly resonant, single-frequency optical parametric oscillator (OPO) has been developed for the 2.6-4.7 mum infrared wavelength region, using a high power (>20 W), widely tunable (1024-1034 nm) Yb:YAG pump source. With the OPO frequency stabilized with an intracavity etalon, the OPO achieved

Far infrared spectroscopy of H II regions

International Nuclear Information System (INIS)

Ward, D.B.

1976-01-01

A fully liquid helium cooled grating spectrometer has been developed for far infrared observations from the NASA Lear Jet. This instrument has been used in observations of the galactic HII regions M42 and M17. The instrument is described, and the results of various performance tests and calibrations are presented. The methods employed in observations from the Lear Jet are described, and the data analysis procedures are discussed. The results of a search for the (O III) 88.16 micron fine structure line are presented. The intensity of the line in M17 is reported, and an upper limit given for the intensity in M42. These results are compared with theoretical predictions, and future applications of infrared line observations are discussed. Coarse resolution spectra of M42 and M17 from 45 to 115 microns are also presented. The emission from M42 is shown to be a very smooth function of wavelength, closely fitting the wavelength dependence of a 105 0 K graybody. The spectrum of M17 is very different, having a bump at approximately 75 microns and a general far infrared excess. The observed spectrum is compared to the predictions of models for M17

Electrical versus optical pumping of quantum dot amplifiers

DEFF Research Database (Denmark)

Berg, Tommy Winther; Bischoff, Svend; Mørk, Jesper

2001-01-01

The influence of the pumping mechanism for the dynamical properties of quantum dot amplifiers is investigated for 10, 40 and 160 GHz signals. A fast response is predicted in the case of optical pumping in the wetting layer (WL). The combination of fast relaxation and capture times and the presence...... of a reservoir of carriers in the WL opens up for the possibility of ultrafast gain recovery in QD devices. The strength of optical contra electrical pumping is that it reduces the bottleneck effect of a slow WL. Optical pumping thus allows significant improvement of the dynamical properties of QD devices....

The polarization of the far-infrared radiation from the Galactic center

Science.gov (United States)

Werner, M. W.; Davidson, J. A.; Morris, M.; Novak, G.; Platt, S. R.

1988-01-01

The first detection of linear polarization of the far-infrared (100-micron) radiation from the about 3-pc-diameter dust ring surrounding the galactic nucleus is reported. The percentage of polarization is between 1 and 2 percent at the three measured positions. It is argued that the polarized radiation is produced by thermal emission from elongated interstellar grains oriented by the local magnetic field. The dust ring is optically thin at 100 microns; therefore the observations sample dust through the entire depth of the cloud and are free of confusing effects due to embedded sources, scattering, or selective absorption. These data provide the first information about the configuration of the magnetic field in the dust ring.

THE ORIGIN OF THE INFRARED EMISSION IN RADIO GALAXIES. II. ANALYSIS OF MID- TO FAR-INFRARED SPITZER OBSERVATIONS OF THE 2JY SAMPLE

International Nuclear Information System (INIS)

Dicken, D.; Tadhunter, C.; Axon, D.; Morganti, R.; Inskip, K. J.; Holt, J.; Groves, B.; Delgado, R. Gonzalez

2009-01-01

We present an analysis of deep mid- to far-infrared (MFIR) Spitzer photometric observations of the southern 2Jy sample of powerful radio sources (0.05 < z < 0.7), conducting a statistical investigation of the links between radio jet, active galactic nucleus (AGN), starburst activity and MFIR properties. This is part of an ongoing extensive study of powerful radio galaxies that benefits from both complete optical emission line information and a uniquely high detection rate in the far-infrared (far-IR). We find tight correlations between the MFIR and [O III]λ5007 emission luminosities, which are significantly better than those between MFIR and extended radio luminosities, or between radio and [O III] luminosities. Since [O III] is a known indicator of intrinsic AGN power, these correlations confirm AGN illumination of the circumnuclear dust as the primary heating mechanism for the dust producing thermal MFIR emission at both 24 and 70 μm. We demonstrate that AGN heating is energetically feasible, and identify the narrow-line region clouds as the most likely location of the cool, far-IR emitting dust. Starbursts make a major contribution to the heating of the cool dust in only 15%-28% of our targets. We also investigate the orientation dependence of the continuum properties, finding that the broad- and narrow-line objects in our sample with strong emission lines have similar distributions of MFIR luminosities and colors. Therefore our results are entirely consistent with the orientation-based unified schemes for powerful radio galaxies. However, the weak line radio galaxies form a separate class of objects with intrinsically low-luminosity AGNs in which both the optical emission lines and the MFIR continuum are weak.

Far-infrared and CO observations of NGC 6357 and regions surrounding NGC 6357 and NGC 6334

International Nuclear Information System (INIS)

McBreen, B.; Jaffe, D.T.; Fazio, G.G.

1983-01-01

We have surveyed two 1.7 square degree sections of the galactic plane at 70 μm with one-arcminute resolution. The scanned areas included the giant southern H II region complexes NGC 6357 and NGC 6334. Nineteen far-infrared sources were observed. The sources range in luminosity from 1.6 x 10 4 to 5.5 x 10 5 L/sub sun/ . We present far-infrared continuum and CO line observations of NGC 6357. Four far-infrared sources were found in this complex and for one of these sources the exciting stars are identified. We present far-infrared and CO observations of sources in the field surrounding NGC 6357 and NGC 6334. The far-infrared sources coincide frequently with CO line temperature peaks. The CO clouds which surround the far-infrared sources have similar 13 CO column densities. Two of the far-infrared sources in the field have associated OH and H 2 O maser emission and compact H II regions

Analysis of cirrus cloud spectral signatures in the far infrared

International Nuclear Information System (INIS)

Maestri, T.; Rizzi, R.; Tosi, E.; Veglio, P.; Palchetti, L.; Bianchini, G.; Di Girolamo, P.; Masiello, G.; Serio, C.; Summa, D.

2014-01-01

This paper analyses high spectral resolution downwelling radiance measurements in the far infrared in the presence of cirrus clouds taken by the REFIR-PAD interferometer, deployed at 3500 m above the sea level at the Testa Grigia station (Italy), during the Earth COoling by WAter vapouR emission (ECOWAR) campaign. Atmospheric state and cloud geometry are characterised by the co-located millimeter-wave spectrometer GBMS and by radiosonde profile data, an interferometer (I-BEST) and a Raman lidar system deployed at a nearby location (Cervinia). Cloud optical depth and effective diameter are retrieved from REFIR-PAD data using a limited number of channels in the 820–960 cm −1 interval. The retrieved cloud parameters are the input data for simulations covering the 250–1100 cm −1 band in order to test our ability to reproduce the REFIR-PAD spectra in the presence of ice clouds. Inverse and forward simulations are based on the same radiative transfer code. A priori information concerning cloud ice vertical distribution is used to better constrain the simulation scheme and an analysis of the degree of approximation of the phase function within the radiative transfer codes is performed to define the accuracy of computations. Simulation-data residuals over the REFIR-PAD spectral interval show an excellent agreement in the window region, but values are larger than total measurement uncertainties in the far infrared. Possible causes are investigated. It is shown that the uncertainties related to the water vapour and temperature profiles are of the same order as the sensitivity to the a priori assumption on particle habits for an up-looking configuration. In case of a down-looking configuration, errors due to possible incorrect description of the water vapour profile would be drastically reduced. - Highlights: • We analyze down-welling spectral radiances in the far infrared (FIR) spectrum. • Discuss the scattering in the fir and the ice crystals phase function

Far-and mid-infrared properties of carbon layers elaborated by plasma sputtering

Energy Technology Data Exchange (ETDEWEB)

Rousseau, Benoit, E-mail: benoit.rousseau@univ-nantes.fr [Université de Nantes, CNRS, LTN UMR6607, La Chantrerie, Rue Christian Pauc, B.P. 50609, F-44306 Nantes Cedex 3 (France); Ammar, Mohamed Ramzi; Bormann, Denis; Simon, Patrick [CNRS, CEMHTI UPR3079, Université d' Orléans, F-55071 (France); Rabat, Hervé; Brault, Pascal [Université d' Orléans, CNRS, GREMI UMR7344, BP 6744, F-45067 Orléans Cedex 2 (France)

2016-12-30

Highlights: • Magnetron sputtering deposition of columnar, disordered carbon films. • Sputtered carbon films infrared properties are dependent on the local order. • Film texture at the micro-nanoscale explains difference of optical properties. - Abstract: The far-and mid-infrared reflectivity spectra of two carbon layers deposited on pure (100) silicon substrates by DC magnetron sputtering were investigated at room temperature in the 10–5000 cm{sup −1} wavenumber range. Their structural and textural features were also studied by combining Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM), X-Ray Reflectivity (XRR) and Rutherford Backscattering Spectroscopy (RBS). The set of results was used to discuss afterwards the influence of the texture on the infrared properties at varying length scale. Thereby, the two layers were found to be heterogeneous as assessed by RBS, XRR and FESEM and their thicknesses had been measured by XRR and FESEM. The information on the structural organization and “crystallite” size was given by Raman spectroscopy. The influence of both the textural and structural parameters on the measured infrared reflectivity spectra was discussed. Finally, a methodology was proposed to recover the intrinsic index of refraction and the intrinsic index of absorption of each layer.

Studies on the hyperthermic effect of the body on utilization of far infrared radiation

Energy Technology Data Exchange (ETDEWEB)

Ryu, Yong Wun; Cho, Chul Ku; Kim, Kyung Jung [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

1996-12-01

This study investigated that strong heat reaction of far infrared radiation material could have the possibility for hyperthermia in patients. Objective was CaSki cell, human uterocervical cancer cell line and they observed descending effect remarkably to compare the effect of cell death by high temperature due to far infrared radiation, platelet numbers of experimental group to compare the control were increased 7 {approx} 17%, and lymphocyte numbers 20 {approx} 40 %. High acidity in tumor tissue due to the concentration of lactic acid, so the effects of far infrared had the result to the possibility to reduce the fatigue stuff. The secretion of endorphin as cerebroneuron substance than epinephrine, sympathetic nerve substance could be reduction of pain in cancer patients because of the effect of far infrared. Above data of experiment, we were found multiple the biological efficacy of far infrared about the possibility of medical utilization. (author). 10 refs., 4 tabs., 3 figs.

Studies on the hyperthermic effect of the body on utilization of far infrared radiation

International Nuclear Information System (INIS)

Ryu, Yong Wun; Cho, Chul Ku; Kim, Kyung Jung

1996-12-01

This study investigated that strong heat reaction of far infrared radiation material could have the possibility for hyperthermia in patients. Objective was CaSki cell, human uterocervical cancer cell line and they observed descending effect remarkably to compare the effect of cell death by high temperature due to far infrared radiation, platelet numbers of experimental group to compare the control were increased 7 ∼ 17%, and lymphocyte numbers 20 ∼ 40 %. High acidity in tumor tissue due to the concentration of lactic acid, so the effects of far infrared had the result to the possibility to reduce the fatigue stuff. The secretion of endorphin as cerebroneuron substance than epinephrine, sympathetic nerve substance could be reduction of pain in cancer patients because of the effect of far infrared. Above data of experiment, we were found multiple the biological efficacy of far infrared about the possibility of medical utilization. (author). 10 refs., 4 tabs., 3 figs

Comparison of laser-based mitigation of fused silica surface damage using mid- versus far-infrared lasers

Energy Technology Data Exchange (ETDEWEB)

Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

2009-12-16

Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser is more efficient than mitigation with a 10.6 {micro}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {micro}m in depth.

Meso-ester and carboxylic acid substituted BODIPYs with far-red and near-infrared emission for bioimaging applications

KAUST Repository

Ni, Yong; Zeng, Lintao; Kang, Namyoung; Huang, Kuo-Wei; Wang, Liang; Zeng, Zebing; Chang, Young-Tae; Wu, Jishan

2014-01-01

-6) become partially soluble in water, and their absorptions and emissions are located in the far-red or near-infrared region. Three synthetic approaches are attempted to access the meso-carboxylic acid (COOH)-substituted BODIPYs 7 and 8 from the meso

Optically pumped laser systems

International Nuclear Information System (INIS)

DeMaria, A.J.; Mack, M.E.

1975-01-01

Laser systems which are pumped by an electric discharge formed in a gas are disclosed. The discharge is in the form of a vortex stabilized electric arc which is triggered with an auxiliary energy source. At high enough repetition rates residual ionization between successive pulses contributes to the pulse stabilization. The arc and the gain medium are positioned inside an optical pumping cavity where light from the arc is coupled directly into the gain medium

Realizing A Mid-Infrared Optically Pumped Molecular Gas Laser Inside Hollow-Core Photonic Crystal Fiber

Science.gov (United States)

2012-01-01

structure resembling a star- of- David pattern can clearly be seen surrounding the hollow core region. The fiber’s hollow core is created by leaving out...O.R. Wood, An optically pumped CO2 laser. IEEE Journal of Quantum Electronics, 1972. 8(6): p. 598. 19. Schlossberg, H.R. and H.R. Fetterman

Ho:YLF pumped HBr laser

CSIR Research Space (South Africa)

Botha, LR

2009-10-01

Full Text Available , “Optically Pumped Mid-Infrared HBr Laser,” IEEE J. Quantum Electron. 30(10), 2395–2400 (1994). 2. C. S. Kletecka, N. Campbell, C. R. Jones, J. W. Nicolson, and W. Rudolph, “Cascade Lasing of Molecular HBr in the Four Micron Region Pumped by a Nd:YAG laser...-Infrared Coherent Sources, (European Physical Society 2009) Invited Talk Mo3. 5. C. Bollig, H. J. Strauss, M. J. D. Esser, W. Koen, M.Schellhorn, D. Preussler, K. Nyangaza, C. Jacobs, E. H. Bernardi and L. R. Botha, “Compact Fibre-Laser-Pumped Ho:YLF Oscillator...

Bolometers for far-infrared and submillimetre astronomy

International Nuclear Information System (INIS)

Griffin, M.J.

2000-01-01

Important scientific goals of far-infrared and submillimetre astronomy include measurements of anisotropies in the cosmic background radiation, deep imaging surveys for detection of high-red-shift galaxies, and imaging and spectroscopy of star formation regions and the interstellar medium in the milky way and nearby galaxies. Use of sensitive bolometer arrays leads to very large improvements in observing speed. Recent progress in the development of bolometric detector systems for ground-based and space-borne far-infrared and submillimetre astronomical observations is reviewed, including spider-web NTD bolometers, transition-edge superconducting sensors, and micromachined planar arrays of ion-implanted silicon bolometers. Future arrays may be based on planar absorbers without feedhorns, which offer potential advantages including more efficient use of space in the focal plane and improved instantaneous sampling of the telescope point spread function, but present challenges in suppression of stray light and RF interference. FIRST and Planck Surveyor are planned satellite missions involving passively cooled (∼70 K) telescopes, and bolometer array developments for these missions are described

Method for generation of tunable far infrared radiation from two-dimensional plasmons

Science.gov (United States)

Katz, Joseph (Inventor)

1989-01-01

Tunable far infrared radiation is produced from two-dimensional plasmons in a heterostructure, which provides large inversion-layer electron densities at the heterointerface, without the need for a metallic grating to couple out the radiation. Instead, a light interference pattern is produced on the planar surface of the heterostructure using two coherent laser beams of a wavelength selected to be strongly absorbed by the heterostructure in order to penetrate through the inversion layer. The wavelength of the far infrared radiation coupled out can then be readily tuned by varying the angle between the coherent beams, or varying the wavelength of the two interfering coherent beams, thus varying the periodicity of the photoconductivity grating to vary the wavelength of the far infrared radiation being coupled out.

FAR-INFRARED EXTINCTION MAPPING OF INFRARED DARK CLOUDS

Energy Technology Data Exchange (ETDEWEB)

Lim, Wanggi [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Tan, Jonathan C. [Departments of Astronomy and Physics, University of Florida, Gainesville, FL 32611 (United States)

2014-01-10

Progress in understanding star formation requires detailed observational constraints on the initial conditions, i.e., dense clumps and cores in giant molecular clouds that are on the verge of gravitational instability. Such structures have been studied by their extinction of near-infrared and, more recently, mid-infrared (MIR) background light. It has been somewhat more of a surprise to find that there are regions that appear as dark shadows at far-infrared (FIR) wavelengths as long as ∼100 μm! Here we develop analysis methods of FIR images from Spitzer-MIPS and Herschel-PACS that allow quantitative measurements of cloud mass surface density, Σ. The method builds on that developed for MIR extinction mapping by Butler and Tan, in particular involving a search for independently saturated, i.e., very opaque, regions that allow measurement of the foreground intensity. We focus on three massive starless core/clumps in the Infrared Dark Cloud (IRDC) G028.37+00.07, deriving mass surface density maps from 3.5 to 70 μm. A by-product of this analysis is the measurement of the spectral energy distribution of the diffuse foreground emission. The lower opacity at 70 μm allows us to probe to higher Σ values, up to ∼1 g cm{sup –2} in the densest parts of the core/clumps. Comparison of the Σ maps at different wavelengths constrains the shape of the MIR-FIR dust opacity law in IRDCs. We find that it is most consistent with the thick ice mantle models of Ossenkopf and Henning. There is tentative evidence for grain ice mantle growth as one goes from lower to higher Σ regions.

FAR-INFRARED EXTINCTION MAPPING OF INFRARED DARK CLOUDS

International Nuclear Information System (INIS)

Lim, Wanggi; Tan, Jonathan C.

2014-01-01

Progress in understanding star formation requires detailed observational constraints on the initial conditions, i.e., dense clumps and cores in giant molecular clouds that are on the verge of gravitational instability. Such structures have been studied by their extinction of near-infrared and, more recently, mid-infrared (MIR) background light. It has been somewhat more of a surprise to find that there are regions that appear as dark shadows at far-infrared (FIR) wavelengths as long as ∼100 μm! Here we develop analysis methods of FIR images from Spitzer-MIPS and Herschel-PACS that allow quantitative measurements of cloud mass surface density, Σ. The method builds on that developed for MIR extinction mapping by Butler and Tan, in particular involving a search for independently saturated, i.e., very opaque, regions that allow measurement of the foreground intensity. We focus on three massive starless core/clumps in the Infrared Dark Cloud (IRDC) G028.37+00.07, deriving mass surface density maps from 3.5 to 70 μm. A by-product of this analysis is the measurement of the spectral energy distribution of the diffuse foreground emission. The lower opacity at 70 μm allows us to probe to higher Σ values, up to ∼1 g cm –2 in the densest parts of the core/clumps. Comparison of the Σ maps at different wavelengths constrains the shape of the MIR-FIR dust opacity law in IRDCs. We find that it is most consistent with the thick ice mantle models of Ossenkopf and Henning. There is tentative evidence for grain ice mantle growth as one goes from lower to higher Σ regions

The Far-Infrared Properties of the Most Isolated Galaxies

Science.gov (United States)

Lisenfeld, U.; Verdes-Montenegro, L.; Sulentic, J.; Leon, S.; Espada, D.; Bergond, G.; García, E.; Sabater, J.; Santander-Vela, J. D.; Verley, S.

2007-05-01

A long-standing question in galaxy evolution involves the role of nature (self-regulation) vs. nurture (environment) on the observed properties (and evolution) of galaxies. A collaboration centreed at the Instituto de Astrofisica de Andalucia (Granada, Spain) is trying to address this question by producing a observational database for a sample of 1050 isolated galaxies from the catalogue of Karachentseva (1973) with the overarching goal being the generation of a "zero-point" sample against which effects of environment on galaxies can be assessed. The AMIGA (Analysis of the Interstellar Medium of Isolated Galaxies) database (see www.iaa.es/AMIGA.html) will include optical, IR and radio line and continuum measures. The galaxies in the sample represent the most isolated galaxies in the local universe. In the present contribution, we will present the project, as well as the results of an analysis of the far-infrared (FIR) and molecular gas properties of this sample.

Synchrotron radiation in the Far-Infrared: Adsorbate-substrate vibrations and resonant interactions

International Nuclear Information System (INIS)

Hoffmann, F.M.; Williams, G.P.; Hirschmugl, C.J.; Chabal, Y.J.

1991-01-01

Synchrotron radiation in the Far Infrared offers the potential for a broadband source of high brightness and intensity. Recent development of a Far-Infrared Beamline at the NSLS in Brookhaven provides an unique high intensity source in the FIR spectral range (800-10 cm -1 ). This talk reviews its application to surface vibrational spectroscopy of low frequency adsorbate-substrate vibrations and resonant interactions on metal surfaces

Advanced infrared optically black baffle materials

International Nuclear Information System (INIS)

Seals, R.D.; Egert, C.M.; Allred, D.D.

1990-01-01

Infrared optically black baffle surfaces are an essential component of many advanced optical systems. All internal surfaces in advanced infrared optical sensors that require stray light management to achieve resolution are of primary concern in baffle design. Current industrial materials need improvements to meet advanced optical sensor systems requirements for optical, survivability, and endurability. Baffles are required to survive and operate in potentially severe environments. Robust diffuse-absorptive black surfaces, which are thermally and mechanically stable to threats of x-ray, launch, and in-flight maneuver conditions, with specific densities to allow an acceptable weight load, handleable during assembly, cleanable, and adaptive to affordable manufacturing, are required as optical baffle materials. In this paper an overview of recently developed advanced infrared optical baffle materials, requirements, manufacturing strategies, and the Optics MODIL (Manufacturing Operations Development and Integration Laboratory) Advanced Baffle Program are discussed

Mission Concept for the Single Aperture Far-Infrared (SAFIR) Observatory

Science.gov (United States)

Benford, Dominic J.; Amato, Michael J.; Mather, John C.; Moseley, S. Harvey, Jr.

2004-01-01

We have developed a preliminary but comprehensive mission concept for SAFIR, as a 10 m-class far-infrared and submillimeter observatory that would begin development later in this decade to meet the needs outlined above. Its operating temperature ( or approx. 40 microns. This would provide a point source sensitivity improvement of several orders of magnitude over that of the Spitzer Space Telescope (previously SIRTF) or the Herschel Space Observatory. Additionally, it would have an angular resolution 12 times finer than that of Spitzer and three times finer than Herschel. This sensitivity and angular resolution are necessary to perform imaging and spectroscopic studies of individual galaxies in the early universe. We have considered many aspects of the SAFIR mission, including the telescope technology (optical design, materials, and packaging), detector needs and technologies, cooling method and required technology developments, attitude and pointing, power systems, launch vehicle, and mission operations. The most challenging requirements for this mission are operating temperature and aperture size of the telescope, and the development of detector arrays. SAFIR can take advantage of much of the technology under development for JWST, but with much less stringent requirements on optical accuracy.

Far-infrared spectroscopic study of CeO2 nanocrystals

International Nuclear Information System (INIS)

Popović, Z. V.; Grujić-Brojčin, M.; Paunović, N.; Radonjić, M. M.; Araújo, V. D.; Bernardi, M. I. B.; Lima, M. M. de; Cantarero, A.

2015-01-01

We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce 1−x Cu x O 2−y (x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50–650 cm −1 spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution. Four oscillators with TO energies of approximately 135, 280, 370, and 490 cm −1 were included in the fitting procedure. These oscillators represent local maxima of the CeO 2 phonon density of states, which is also calculated using the density functional theory. The lowest energy oscillator represents TA(L)/TA(X) phonon states, which become infrared-active E u modes at the L and X points of the Brillouin zone (BZ). The second oscillator originates from TO(Γ) phonon states. The oscillator at ∼400 cm −1 originates from Raman mode phonon states, which at the L point of BZ also becomes infrared-active E u mode. The last oscillator describes phonons with dominantly LO(Γ) infrared mode character. The appearance of phonon density of states related oscillators, instead of single F 2u infrared-active mode in the far-infrared reflectivity spectra, is a consequence of the nanosized dimension of the CeO 2 particles. The best fit spectra are obtained using the generalized Bruggeman model for inhomogeneous media, which takes into account the nanocrystal volume fraction and the pore shape

Anomalously high intercombination line ratios in symbiotic stars; extreme Bowen pumping?

International Nuclear Information System (INIS)

Kastner, S.O.; Bhatia, A.K.; Feibelman, W.A.

1989-01-01

We assemble International Ultraviolet Explorer observations of the ratio of the O III intercombination lines near 1660 A, showing that the observed ratios in symbiotic stars are significantly higher than the theoretically predicted optically thin limit of 2.5. The presence of an enhancing physical process is thereby indicated. It is suggested that Bowen pumping of the lower level of the 1666.2 A line in an 'external saturation' limit, coupled with appreciable optical depth, could logically explain the high ratios. Some tentative evidence for this is presented and the relevance of far-infrared observations of the O III 51.8 and 88.3 μm lines in symbiotic sources is emphasized. (author)

Optical modelling of far-infrared astronomical instrumentation exploiting multimode horn antennas

Science.gov (United States)

O'Sullivan, Créidhe; Murphy, J. Anthony; Mc Auley, Ian; Wilson, Daniel; Gradziel, Marcin L.; Trappe, Neil; Cahill, Fiachra; Peacocke, T.; Savini, G.; Ganga, K.

2014-07-01

In this paper we describe the optical modelling of astronomical telescopes that exploit bolometric detectors fed by multimoded horn antennas. In cases where the horn shape is profiled rather than being a simple cone, we determine the beam at the horn aperture using an electromagnetic mode-matching technique. Bolometers, usually placed in an integrating cavity, can excite many hybrid modes in a corrugated horn; we usually assume they excite all modes equally. If the waveguide section feeding the horn is oversized these modes can propagate independently, thereby increasing the throughput of the system. We use an SVD analysis on the matrix that describes the scattering between waveguide (TE/TM) modes to recover the independent orthogonal fields (hybrid modes) and then propagate these to the sky independently where they are added in quadrature. Beam patterns at many frequencies across the band are then added with a weighting appropriate to the source spectrum. Here we describe simulations carried out on the highest-frequency (857-GHz) channel of the Planck HFI instrument. We concentrate in particular on the use of multimode feedhorns and consider the effects of possible manufacturing tolerances on the beam on the sky. We also investigate the feasibility of modelling far-out sidelobes across a wide band for electrically large structures and bolometers fed by multi-mode feedhorns. Our optical simulations are carried out using the industry-standard GRASP software package.

Far-infrared spectroscopic study of CeO2 nanocrystals

Science.gov (United States)

Popović, Z. V.; Grujić-Brojčin, M.; Paunović, N.; Radonjić, M. M.; Araújo, V. D.; Bernardi, M. I. B.; de Lima, M. M.; Cantarero, A.

2015-01-01

We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce1- x Cu x O2- y ( x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50-650 cm-1 spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution. Four oscillators with TO energies of approximately 135, 280, 370, and 490 cm-1 were included in the fitting procedure. These oscillators represent local maxima of the CeO2 phonon density of states, which is also calculated using the density functional theory. The lowest energy oscillator represents TA(L)/TA(X) phonon states, which become infrared-active E u modes at the L and X points of the Brillouin zone (BZ). The second oscillator originates from TO(Γ) phonon states. The oscillator at 400 cm-1 originates from Raman mode phonon states, which at the L point of BZ also becomes infrared-active E u mode. The last oscillator describes phonons with dominantly LO(Γ) infrared mode character. The appearance of phonon density of states related oscillators, instead of single F 2uinfrared-active mode in the far-infrared reflectivity spectra, is a consequence of the nanosized dimension of the CeO2 particles. The best fit spectra are obtained using the generalized Bruggeman model for inhomogeneous media, which takes into account the nanocrystal volume fraction and the pore shape.

Near-infrared observations of the far-infrared source V region in NGC 6334

International Nuclear Information System (INIS)

Fischer, J.; Joyce, R.R.; Simon, M.; Simon, T.

1982-01-01

We have observed a very red near-infrared source at the center of NGC 6334 FIRS V, a far-infrared source suspected of variability by McBreen et al. The near-infrared source has deep ice and silicate absorption bands, and its half-power size at 20 μm is approx.15'' x 10''. Over the past 2 years we have observed no variability in the near-infrared flux. We have also detected an extended source of H 2 line emission in this region. The total luminosity in the H 2 v-1--0 S(1) line, uncorrected for extinction along the line of sight, is 0.3 L/sub sun/. Detection of emission in high-velocity wings of the J = 1--0 12 CO line suggests that the H 2 emission is associated with a supersonic gas flow

Microwave, Millimeter, Submillimeter, and Far Infrared Spectral Databases

Science.gov (United States)

Pearson, J. C.; Pickett, H. M.; Drouin, B. J.; Chen, P.; Cohen, E. A.

2002-01-01

The spectrum of most known astrophysical molecules is derived from transitions between a few hundred to a few hundred thousand energy levels populated at room temperature. In the microwave and millimeter wave regions. spectroscopy is almost always performed with traditional microwave techniques. In the submillimeter and far infrared microwave technique becomes progressively more technologically challenging and infrared techniques become more widely employed as the wavelength gets shorter. Infrared techniques are typically one to two orders of magnitude less precise but they do generate all the strong features in the spectrum. With microwave technique, it is generally impossible and rarely necessary to measure every single transition of a molecular species, so careful fitting of quantum mechanical Hamiltonians to the transitions measured are required to produce the complete spectral picture of the molecule required by astronomers. The fitting process produces the most precise data possible and is required in the interpret heterodyne observations. The drawback of traditional microwave technique is that precise knowledge of the band origins of low lying excited states is rarely gained. The fitting of data interpolates well for the range of quantum numbers where there is laboratory data, but extrapolation is almost never precise. The majority of high resolution spectroscopic data is millimeter or longer in wavelength and a very limited number of molecules have ever been studied with microwave techniques at wavelengths shorter than 0.3 millimeters. The situation with infrared technique is similarly dire in the submillimeter and far infrared because the black body sources used are competing with a very significant thermal background making the signal to noise poor. Regardless of the technique used the data must be archived in a way useful for the interpretation of observations.

Optical pumping production of spin polarized hydrogen

International Nuclear Information System (INIS)

Knize, R.J.; Happer, W.; Cecchi, J.L.

1984-01-01

There has been much interest recently in the production of large quantities of spin polarized hydrogen in various fields including controlled fusion, quantum fluids, high energy, and nuclear physics. One promising method for the development of large quantities of spin polarized hydrogen is the utilization of optical pumping with a laser. Optical pumping is a process where photon angular momentum is converted into electron and nuclear spin. The advent of tunable CW dye lasers (approx. 1 watt) allow the production of greater than 10 18 polarized atoms/sec. We have begun a program at Princeton to investigate the physics and technology of using optical pumping to produce large quantities of spin polarized hydrogen. Initial experiments have been done in small closed glass cells. Eventually, a flowing system, open target, or polarized ion source could be constructed

Far-infrared spectroscopy of thermally annealed tungsten silicide films

International Nuclear Information System (INIS)

Amiotti, M.; Borghesi, A.; Guizzetti, G.; Nava, F.; Santoro, G.

1991-01-01

The far-infrared transmittance spectrum of tungsten silicide has been observed for the first time. WSi 2 polycrystalline films were prepared by coevaporation and chemical-vapour deposition on silicon wafers, and subsequently thermally annealed at different temperatures. The observed structures are interpreted, on the basis of the symmetry properties of the crystal, such as infrared-active vibrational modes. Moreover, the marked lineshape dependence on annealing temperature enables this technique to analyse the formation of the solid silicide phases

Generating Far-Infrared Radiation By Two-Wave Mixing

Science.gov (United States)

Borenstain, Shmuel

1992-01-01

Far-infrared radiation 1 to 6 GHz generated by two-wave mixing in asymmetrically grown GaAs/AlxGa1-xAs multiple-quantum-well devices. Two near-infrared semiconductor diode lasers phase-locked. Outputs amplified, then combined in semiconductor nonlinear multiple-quantum-well planar waveguide. Necessary to optimize design of device with respect to three factors: high degree of confinement of electromagnetic field in nonlinear medium to maximize power density, phase matching to extend length of zone of interaction between laser beams in non-linear medium, and nonlinear susceptibility. Devices used as tunable local oscillators in heterodyne-detection radiometers.

Far-infrared phonon spectroscopy of Pb1-xMn xTe layers grown by molecular beam epitaxy

International Nuclear Information System (INIS)

Romcevic, N.; Nadolny, A.J.; Romcevic, M.; Story, T.; Taliashvili, B.; Milutinovic, A.; Trajic, J.; Lusakowska, E.; Vasiljevic-Radovic, D.; Domukhovski, V.; Osinniy, V.; Hadzic, B.; Dziawa, P.

2007-01-01

In this paper we used far-infrared spectroscopy, reflection high energy electron diffraction (RHEED), X-ray diffraction and atomic force microscopy (AFM) to investigate structural and optical properties of Pb 1-x Mn x Te layers grown by molecular beam epitaxy (MBE). A numerical model for calculating the reflectivity coefficient for complex systems which include films, buffer layer and substrate has been applied. The infrared reflectivity spectra consist of Pb 1-x Mn x Te phonons, which exhibit intermediate one-two mode behavior, and MnTe phonons. A good agreement between calculated and experimental spectra is achieved. We registered the local distribution of Mn impurities depending on substrate type. For films growth on BaF 2 substrate we registered the orthorhombic local structure of MnTe clusters, while in the case of KCl substrate this structure is cubic. The Pb 1-x Mn x Te long wavelength optical phonons were described by the modified Genzel's model

An electro-optical timing diagnostic for pump-probe experiments at the free-electron laser in Hamburg FLASH

International Nuclear Information System (INIS)

Azima, Armin

2009-07-01

Femtosecond pump-probe experiments have extensively been used to follow atomic and molecular motion in time. The very intense extreme ultraviolet XUV light of the Free electron LASer in Hamburg FLASH facility allows to investigate fundamental processes such as direct one or few photon inner shell ionizations. A supplementary Ti:Sapphire near infrared femtosecond laser system allows to perform two-color pump-probe experiments with FLASH involving intense laser fields of hugely different photon energies. Within this work a bunch arrival measurement system has been built, which assists these two-color pump-probe experiments to reduce the temporal jitter of FLASH and to increase the temporal resolution. The diagnostic is based upon an electro-optical detection scheme and measures the relative arrival time between the Ti:Sapphire femtosecond pulse and the electron bunch, which generates the self-amplified by stimulated emission SASE XUV pulse in the undulator section of FLASH. Key feature of the diagnostic is a 150 m long glass fiber pulse transport line, which inflicts non-linear dispersion. A dispersion control system to compensate for this higher order dispersion has been developed including the control and programming of a spatial light phase modulator. It was possible to transport a 90 fs FWHM short near infrared femtosecond laser pulse Fourier limited by the dispersion compensated glass fiber. The electro-optical signal induced by the FLASH electron bunch was generated, characterized and optimized. The signal features beside the designated bunch arrival timing capability the additional possibility to measure the longitudinal electron bunch density distribution of an arbitrary bunch of FLASH in a single shot with a temporal resolution of below 100 fs RMS. Timing and bunch analysis capabilities of the developed diagnostic have been cross-checked with other comparable diagnostics at FLASH like the transversal deflecting cavity structure named LOLA. Finally, the

An electro-optical timing diagnostic for pump-probe experiments at the free-electron laser in Hamburg FLASH

Energy Technology Data Exchange (ETDEWEB)

Azima, Armin

2009-07-15

Femtosecond pump-probe experiments have extensively been used to follow atomic and molecular motion in time. The very intense extreme ultraviolet XUV light of the Free electron LASer in Hamburg FLASH facility allows to investigate fundamental processes such as direct one or few photon inner shell ionizations. A supplementary Ti:Sapphire near infrared femtosecond laser system allows to perform two-color pump-probe experiments with FLASH involving intense laser fields of hugely different photon energies. Within this work a bunch arrival measurement system has been built, which assists these two-color pump-probe experiments to reduce the temporal jitter of FLASH and to increase the temporal resolution. The diagnostic is based upon an electro-optical detection scheme and measures the relative arrival time between the Ti:Sapphire femtosecond pulse and the electron bunch, which generates the self-amplified by stimulated emission SASE XUV pulse in the undulator section of FLASH. Key feature of the diagnostic is a 150 m long glass fiber pulse transport line, which inflicts non-linear dispersion. A dispersion control system to compensate for this higher order dispersion has been developed including the control and programming of a spatial light phase modulator. It was possible to transport a 90 fs FWHM short near infrared femtosecond laser pulse Fourier limited by the dispersion compensated glass fiber. The electro-optical signal induced by the FLASH electron bunch was generated, characterized and optimized. The signal features beside the designated bunch arrival timing capability the additional possibility to measure the longitudinal electron bunch density distribution of an arbitrary bunch of FLASH in a single shot with a temporal resolution of below 100 fs RMS. Timing and bunch analysis capabilities of the developed diagnostic have been cross-checked with other comparable diagnostics at FLASH like the transversal deflecting cavity structure named LOLA. Finally, the

Ultrafast Silicon Photonics with Visible to Mid-Infrared Pumping of Silicon Nanocrystals.

Science.gov (United States)

Diroll, Benjamin T; Schramke, Katelyn S; Guo, Peijun; Kortshagen, Uwe R; Schaller, Richard D

2017-10-11

Dynamic optical control of infrared (IR) transparency and refractive index is achieved using boron-doped silicon nanocrystals excited with mid-IR optical pulses. Unlike previous silicon-based optical switches, large changes in transmittance are achieved without a fabricated structure by exploiting strong light coupling of the localized surface plasmon resonance (LSPR) produced from free holes of p-type silicon nanocrystals. The choice of optical excitation wavelength allows for selectivity between hole heating and carrier generation through intraband or interband photoexcitation, respectively. Mid-IR optical pumping heats the free holes of p-Si nanocrystals to effective temperatures greater than 3500 K. Increases of the hole effective mass at high effective hole temperatures lead to a subpicosecond change of the dielectric function, resulting in a redshift of the LSPR, modulating mid-IR transmission by as much as 27%, and increasing the index of refraction by more than 0.1 in the mid-IR. Low hole heat capacity dictates subpicosecond hole cooling, substantially faster than carrier recombination, and negligible heating of the Si lattice, permitting mid-IR optical switching at terahertz repetition frequencies. Further, the energetic distribution of holes at high effective temperatures partially reverses the Burstein-Moss effect, permitting the modulation of transmittance at telecommunications wavelengths. The results presented here show that doped silicon, particularly in micro- or nanostructures, is a promising dynamic metamaterial for ultrafast IR photonics.

Far infrared reflectivity study of ceramic superconductors

International Nuclear Information System (INIS)

Memon, A.; Khan, M.N.; Al-Dallal, S.; Tanner, D.B.; Porter, C.D.

1992-01-01

In this paper, the authors report on a study of the far-infrared reflectivity of mixed rare earths and lanthnides ceramic superconductors RBa 2 Cu 3 O 7 in the normal state. The authors' results show that the strength of the phonon modes is reduced when yttrium is partially replaced by gadolinium and europium. Also the critical temperature of these mixed materials is reduced as indicated by the four probe technique

Multimode simulations of a wide field of view double-Fourier far-infrared spatio-spectral interferometer

Science.gov (United States)

Bracken, Colm P.; Lightfoot, John; O'Sullivan, Creidhe; Murphy, J. Anthony; Donohoe, Anthony; Savini, Giorgio; Juanola-Parramon, Roser; The Fisica Consortium, On Behalf Of

2018-01-01

In the absence of 50-m class space-based observatories, subarcsecond astronomy spanning the full far-infrared wavelength range will require space-based long-baseline interferometry. The long baselines of up to tens of meters are necessary to achieve subarcsecond resolution demanded by science goals. Also, practical observing times command a field of view toward an arcminute (1‧) or so, not achievable with a single on-axis coherent detector. This paper is concerned with an application of an end-to-end instrument simulator PyFIInS, developed as part of the FISICA project under funding from the European Commission's seventh Framework Programme for Research and Technological Development (FP7). Predicted results of wide field of view spatio-spectral interferometry through simulations of a long-baseline, double-Fourier, far-infrared interferometer concept are presented and analyzed. It is shown how such an interferometer, illuminated by a multimode detector can recover a large field of view at subarcsecond angular resolution, resulting in similar image quality as that achieved by illuminating the system with an array of coherent detectors. Through careful analysis, the importance of accounting for the correct number of higher-order optical modes is demonstrated, as well as accounting for both orthogonal polarizations. Given that it is very difficult to manufacture waveguide and feed structures at sub-mm wavelengths, the larger multimode design is recommended over the array of smaller single mode detectors. A brief note is provided in the conclusion of this paper addressing a more elegant solution to modeling far-infrared interferometers, which holds promise for improving the computational efficiency of the simulations presented here.

Far-infrared spectrophotometer for astronomical observations

Science.gov (United States)

Moseley, H.; Silverberg, R. F.

1981-01-01

A liquid-helium-cooled far infrared spectrophotometer was built and used to make low resolution observations of the continua of several kinds of astronomical objects using the Kuiper Airborne Observatory. This instrument fills a gap in both sensitivity to continuum sources and spectral resolution between the broadband photometers with lambda/Delta lambda approximately 1 and spectrometers with lambda/Delta lambda greater than 50. While designed primarily to study planetary nebulae, the instrument permits study of the shape of the continua of many weak sources which cannot easily be observed with high resolution systems.

Far-infrared spectra of acetanilide revisited

Science.gov (United States)

Spire, A.; Barthes, M.; Kellouai, H.; De Nunzio, G.

2000-03-01

A new investigation of the temperature dependence of the far-infrared spectra of acetanilide and some isotopomers is presented. Four absorption bands are considered at 31, 42, 64, and 80 cm-1, and no significant change of their integrated intensity is observed when reducing the temperature. The temperature induced frequency shift values and other properties of these bands are consistent with an assignment as anharmonic lattice phonons. These results rule out the assignment of the 64, 80, and 106 cm-1 bands as normal modes of the polaronic excitation, as previously suggested.

Mathematical model of an optically pumped molecular laser

CSIR Research Space (South Africa)

Botha, LR

2009-07-01

Full Text Available A mathematical model was developed that accurately predicts the performance of an optically pumped HBr laser. Relatively high conversion efficiency was achieved. Tm pumped Ho:YLF is a viable source for pumping HBr laser, while HBr can be scaled...

Metal-Insulator Phase Transition in thin VO2 films: A Look from the Far Infrared Side

DEFF Research Database (Denmark)

Jepsen, Peter Uhd; Fischer, B. M.; Thoman, A.

Vanadium dioxide (VO2) displays a well-known metal-insulator (MI) transition at atemperature of 68oC. The MI transition in VO2 has been studied extensively by a widerange of optical, electrical, structural, and magnetic measurements. In spite of this there isstill some controversy about the nature...... temperature hysteresis of the far-infrared transmission through thethin film with temperature. Interestingly the temperature-dependent transmissionamplitude shows a markedly different switching temperature than the transmission phase.This effect has not been observed before, and is very important...

Optical bistability via quantum interference from incoherent pumping and spontaneous emission

International Nuclear Information System (INIS)

Sahrai, M.; Asadpour, S.H.; Sadighi-Bonabi, R.

2011-01-01

We theoretically investigate the optical bistability (OB) in a V-type three-level atomic system confined in a unidirectional ring cavity via incoherent pumping field. It is shown that the threshold of optical bistability can be controlled by the rate of an incoherent pumping field and by interference mechanism arising from the spontaneous emission and incoherent pumping field. We demonstrate that the optical bistability converts to optical multi-stability (OM) by the quantum interference mechanism. - Highlights: → We modulate the optical bistability (OB) in a four-level N-type atomic system. → The threshold of optical bistability can be controlled by the quantum interferences. → OB converts to optical multi-stability (OM) by the quantum interferences. → We discuss the effect of an incoherent pumping field on reduction of OB threshold.

Efficient Long Wave IR Laser from Ho:YAG 2 {mu}m Pumped ZnGeP{sub 2} Optical Parametric Oscillator

Energy Technology Data Exchange (ETDEWEB)

Li-Gang,; Bao-Quan, Yao; Xiao-Ming, Duan; Guo-Li, Zhu; Yue-Zhu, Wang; You-Lun, Ju [National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150001 (China)

2010-01-15

An efficient high power long wave infrared laser based on ZnGeP{sub 2} optical parametric oscillator pumped by a 2.09 {mu}m Tm:YLF/Ho:YAG laser at 10KHz pulse repetition rate is reported. The pump to idler conversion efficiency is 8% at 15.6 W Ho pump power level and a quantum efficiency of 31 % when the 1'idler wavelength is tuned at 8.08 {mu}m. The wavelength tuning range from 8-9.1 {mu}m is also achieved by rotating the ZGP crystal. (fundamental areas of phenomenology(including applications))

From Selenium- to Tellurium-Based Glass Optical Fibers for Infrared Spectroscopies

Directory of Open Access Journals (Sweden)

Jacques Lucas

2013-05-01

Full Text Available Chalcogenide glasses are based on sulfur, selenium and tellurium elements, and have been studied for several decades regarding different applications. Among them, selenide glasses exhibit excellent infrared transmission in the 1 to 15 µm region. Due to their good thermo-mechanical properties, these glasses could be easily shaped into optical devices such as lenses and optical fibers. During the past decade of research, selenide glass fibers have been proved to be suitable for infrared sensing in an original spectroscopic method named Fiber Evanescent Wave Spectroscopy (FEWS. FEWS has provided very nice and promising results, for example for medical diagnosis. Then, some sophisticated fibers, also based on selenide glasses, were developed: rare-earth doped fibers and microstructured fibers. In parallel, the study of telluride glasses, which can have transmission up to 28 µm due to its atom heaviness, has been intensified thanks to the DARWIN mission led by the European Space Agency (ESA. The development of telluride glass fiber enables a successful observation of CO2 absorption band located around 15 µm. In this paper we review recent results obtained in the Glass and Ceramics Laboratory at Rennes on the development of selenide to telluride glass optical fibers, and their use for spectroscopy from the mid to the far infrared ranges.

Far-infrared spectral studies of magnesium and aluminum co ...

Indian Academy of Sciences (India)

Far-infrared absorption spectroscopy has been used to study the occurrence of var- ... density of the products was found to be about 83% of the X-ray density. ..... [15] B D Cullity, Elements of X-ray diffraction (Addison-Wesley Press, Reading, ...

High resolution spectroscopy in the microwave and far infrared

Science.gov (United States)

Pickett, Herbert M.

1990-01-01

High resolution rotational spectroscopy has long been central to remote sensing techniques in atmospheric sciences and astronomy. As such, laboratory measurements must supply the required data to make direct interpretation of data for instruments which sense atmospheres using rotational spectra. Spectral measurements in the microwave and far infrared regions are also very powerful tools when combined with infrared measurements for characterizing the rotational structure of vibrational spectra. In the past decade new techniques were developed which have pushed high resolution spectroscopy into the wavelength region between 25 micrometers and 2 mm. Techniques to be described include: (1) harmonic generation of microwave sources, (2) infrared laser difference frequency generation, (3) laser sideband generation, and (4) ultrahigh resolution interferometers.

Far infrared radiation promotes rabbit renal proximal tubule cell proliferation and functional characteristics, and protects against cisplatin-induced nephrotoxicity.

Science.gov (United States)

Chiang, I-Ni; Pu, Yeong-Shiau; Huang, Chao-Yuan; Young, Tai-Horng

2017-01-01

Far infrared radiation, a subdivision of the electromagnetic spectrum, is beneficial for long-term tissue healing, anti-inflammatory effects, growth promotion, sleep modulation, acceleration of microcirculation, and pain relief. We investigated if far infrared radiation is beneficial for renal proximal tubule cell cultivation and renal tissue engineering. We observed the effects of far infrared radiation on renal proximal tubules cells, including its effects on cell proliferation, gene and protein expression, and viability. We also examined the protective effects of far infrared radiation against cisplatin, a nephrotoxic agent, using the human proximal tubule cell line HK-2. We found that daily exposure to far infrared radiation for 30 min significantly increased rabbit renal proximal tubule cell proliferation in vitro, as assessed by MTT assay. Far infrared radiation was not only beneficial to renal proximal tubule cell proliferation, it also increased the expression of ATPase Na+/K+ subunit alpha 1 and glucose transporter 1, as determined by western blotting. Using quantitative polymerase chain reaction, we found that far infrared radiation enhanced CDK5R1, GNAS, NPPB, and TEK expression. In the proximal tubule cell line HK-2, far infrared radiation protected against cisplatin-mediated nephrotoxicity by reducing apoptosis. Renal proximal tubule cell cultivation with far infrared radiation exposure resulted in better cell proliferation, significantly higher ATPase Na+/K+ subunit alpha 1 and glucose transporter 1 expression, and significantly enhanced expression of CDK5R1, GNAS, NPPB, and TEK. These results suggest that far infrared radiation improves cell proliferation and differentiation. In HK-2 cells, far infrared radiation mediated protective effects against cisplatin-induced nephrotoxicity by reducing apoptosis, as indicated by flow cytometry and caspase-3 assay.

Electromagnetic modelling of a space-borne far-infrared interferometer

Science.gov (United States)

Donohoe, Anthony; O'Sullivan, Créidhe; Murphy, J. Anthony; Bracken, Colm; Savini, Giorgio; Pascale, Enzo; Ade, Peter; Sudiwala, Rashmi; Hornsby, Amber

2016-02-01

In this paper I will describe work done as part of an EU-funded project `Far-infrared space interferometer critical assessment' (FISICA). The aim of the project is to investigate science objectives and technology development required for the next generation THz space interferometer. The THz/FIR is precisely the spectral region where most of the energy from stars, exo-planetary systems and galaxy clusters deep in space is emitted. The atmosphere is almost completely opaque in the wave-band of interest so any observation that requires high quality data must be performed with a space-born instrument. A space-borne far infrared interferometer will be able to answer a variety of crucial astrophysical questions such as how do planets and stars form, what is the energy engine of most galaxies and how common are the molecule building blocks of life. The FISICA team have proposed a novel instrument based on a double Fourier interferometer that is designed to resolve the light from an extended scene, spectrally and spatially. A laboratory prototype spectral-spatial interferometer has been constructed to demonstrate the feasibility of the double-Fourier technique at far infrared wavelengths (0.15 - 1 THz). This demonstrator is being used to investigate and validate important design features and data-processing methods for future instruments. Using electromagnetic modelling techniques several issues related to its operation at long baselines and wavelengths, such as diffraction, have been investigated. These are critical to the design of the concept instrument and the laboratory testbed.

Scaling of an Optically Pumped Mid-Infrared Rubidium Laser

Science.gov (United States)

2015-03-26

beam, and the saturation intensity, Isat , was calculated using Equation 4.6: = ℎ( + ) , (6) where h is the...4.91 mm2, the intensity of the laser at a pump energy of 0.05 mJ was 10.2 mW/cm2. Thus I/ Isat ~ 290, so ∆νsat should have been about 17 times... Isat ~ 5796, so ∆νsat should have been about 76∆νD, in reasonable agreement with the experimental result of 53∆νD. Rb Laser Output Energy vs. Pump

Transmission Spectra of HgTe-Based Quantum Wells and Films in the Far-Infrared Range

Science.gov (United States)

Savchenko, M. L.; Vasil'ev, N. N.; Yaroshevich, A. S.; Kozlov, D. A.; Kvon, Z. D.; Mikhailov, N. N.; Dvoretskii, S. A.

2018-04-01

Strained 80-nm-thick HgTe films belong to a new class of materials referred to as three-dimensional topological insulators (i.e., they have a bulk band gap and spin-nondegenerate surface states). Though there are a number of studies devoted to analysis of the properties of surface states using both transport and magnetooptical techniques in the THz range, the information about direct optical transitions between bulk and surface bands in these systems has not been reported. This study is devoted to the analysis of transmission and reflection spectra of HgTe films of different thicknesses in the far-infrared range recorded in a wide temperature range in order to detect the above interband transitions. A peculiarity at 15 meV, which is sensitive to a change in the temperature, is observed in spectra of both types. Detailed analysis of the data obtained revealed that this feature is related to absorption by HgTe optical phonons, while the interband optical transitions are suppressed.

ISO far-infrared observations of rich galaxy clusters I. Abell 2670

DEFF Research Database (Denmark)

Hansen, Lene; Jorgensen, H.E.; Nørgaard-Nielsen, Hans Ulrik

1999-01-01

As part of an investigation of far-infrared emission from rich galaxy clusters the central part of Abell 2670 has been mapped with ISO at 60 mu m, 100 mu m, 135 mu m, and 200 mu m using the PHT-C camera. Point sources detected in the field have infrared fluxes comparable to normal spirals...

Optical/Far-Infrared Control of Low-Dimensional Semiconductor Structures

National Research Council Canada - National Science Library

Citrin, David

2003-01-01

.... The manipulation of the carrier and optical dynamics will be achieved by the use of specially tailored ultrafast optical pulses, multicolor laser fields, millimeter or submillimeter electromagnetic...

Towards the mid-infrared optical biopsy

DEFF Research Database (Denmark)

Seddon, Angela B.; Benson, Trevor M.; Sujecki, Slawomir

2016-01-01

We are establishing a new paradigm in mid-infrared molecular sensing, mapping and imaging to open up the mid-infrared spectral region for in vivo (i.e. in person) medical diagnostics and surgery. Thus, we are working towards the mid-infrared optical biopsy ('opsy' look at, bio the biology) in situ...... in the body for real-time diagnosis. This new paradigm will be enabled through focused development of devices and systems which are robust, functionally designed, safe, compact and cost effective and are based on active and passive mid-infrared optical fibers. In particular, this will enable early diagnosis...... of a bright mid-infrared wideband source in a portable package as a first step for medical fiber-based systems operating in the mid-infrared. Moreover, mid-infrared molecular mapping and imaging is potentially a disruptive technology to give improved monitoring of the environment, energy efficiency, security...

Determining hyperfine transitions with electromagnetically induced transparency and optical pumping

International Nuclear Information System (INIS)

Lee Yi-Chi; Tsai Chin-Chun; Huang Chen-Han; Chui Hsiang-Chen; Chang Yung-Yung

2011-01-01

A system is designed to observe the phenomena of electromagnetically induced transparency and optical pumping in cesium D 1 and D 2 lines at room temperature. When a pump laser is frequency-locked on the top of a hyperfine transition and the frequency of the probe laser scans over another hyperfine transition, a spectrum of V-type electromagnetically induced transparency or an optical pumping can be observed depending on whether the two lasers share a common ground state. Therefore, these results can be used to identify the unknown hyperfine transitions of the D 1 line transitions. For educational purposes, this system is helpful for understanding the electromagnetically induced transparency and the optical pumping

Meso-ester and carboxylic acid substituted BODIPYs with far-red and near-infrared emission for bioimaging applications

KAUST Repository

Ni, Yong

2014-01-21

A series of meso-ester-substituted BODIPY derivatives 1-6 are synthesized and characterized. In particular, dyes functionalized with oligo(ethylene glycol) ether styryl or naphthalene vinylene groups at the α positions of the BODIPY core (3-6) become partially soluble in water, and their absorptions and emissions are located in the far-red or near-infrared region. Three synthetic approaches are attempted to access the meso-carboxylic acid (COOH)-substituted BODIPYs 7 and 8 from the meso-ester-substituted BODIPYs. Two feasible synthetic routes are developed successfully, including one short route with only three steps. The meso-COOH-substituted BODIPY 7 is completely soluble in pure water, and its fluorescence maximum reaches around 650 nm with a fluorescence quantum yield of up to 15 %. Time-dependent density functional theory calculations are conducted to understand the structure-optical properties relationship, and it is revealed that the Stokes shift is dependent mainly on the geometric change from the ground state to the first excited singlet state. Furthermore, cell staining tests demonstrate that the meso-ester-substituted BODIPYs (1 and 3-6) and one of the meso-COOH-substituted BODIPYs (8) are very membrane-permeable. These features make these meso-ester- and meso-COOH-substituted BODIPY dyes attractive for bioimaging and biolabeling applications in living cells. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Far-infrared Spectroscopic Characterization of Anti-vinyl Alcohol

Science.gov (United States)

Bunn, Hayley; Soliday, Rebekah M.; Sumner, Isaiah; Raston, Paul L.

2017-09-01

We report a detailed analysis of the high-resolution far-infrared spectrum of anti-vinyl alcohol, which has been previously identified toward Sagittarius B2(N). The ν 15 OH torsional fundamental investigated here is more than 200 cm-1 removed from the next nearest vibration, making it practically unperturbed and ideal to help refine the ground state rotational constants that were previously determined from 25 microwave lines. We assigned 1335 lines within the ν 15 fundamental centered at 261.5512 cm-1, with J and K a ranges of 1-59 and 0-16, respectively. The microwave and far-infrared line positions were fit with Watson-type A- and S-reduced Hamiltonians, with the inclusion of quartic and select sextic distortion terms. This resulted in a significant refinement of the ground state constants, in addition to the determination of the {ν }15=1 state constants for the first time. The spectroscopic parameters are in good agreement with the results from anharmonic coupled-cluster calculations, and should be useful in searches for rotationally and/or vibrationally warm anti-vinyl alcohol in interstellar molecular clouds.

A ZnGeP{sub 2} Optical Parametric Oscillator with Mid-IR Output Power 3 W Pumped by a Tm, Ho:GdVO{sub 4} Laser

Energy Technology Data Exchange (ETDEWEB)

Bao-Quan, Yao; Guo-Li, Zhu; You-Lun, Ju; Yue-Zhu, Wang [National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150080 (China)

2009-02-15

We report an efficient mid-infrared optical parametric oscillator (OPO) pumped by a pulsed Tm,Ho-codoped GdVO4 laser. The 10-W Tm,Ho:GdVO4 laser pumped by a 801 nm diode produces 20ns pulses with a repetition rate of 10kHz at wavelength of 2.048 {mu}m. The ZnGeP{sub 2} (ZGP) OPO produces 15-ns pulses in the spectral regions 3.65-3.8 {mu}m and 4.45-4.65 {mu}m simultaneously. More than 3 W of mid-IR output power can be generated with a total OPO slope efficiency greater than 58% corresponding to incident 2 {mu}m pump power. The diode laser pump to mid-IR optical conversion efficiency is about 12%.

Far-infrared spectroscopic study of CeO{sub 2} nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Popović, Z. V., E-mail: zoran.popovic@ipb.ac.rs; Grujić-Brojčin, M.; Paunović, N. [University of Belgrade, Center for Solid State Physics and New Materials, Institute of Physics (Serbia); Radonjić, M. M. [University of Belgrade, Scientific Computing Laboratory, Institute of Physics Belgrade (Serbia); Araújo, V. D.; Bernardi, M. I. B. [Universidade de São Paulo-USP, Instituto de Fisica (Brazil); Lima, M. M. de; Cantarero, A. [Universidad de Valencia, Instituto de Ciencia de Los Materiales (Spain)

2015-01-15

We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce{sub 1−x}Cu{sub x}O{sub 2−y} (x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50–650 cm{sup −1} spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution. Four oscillators with TO energies of approximately 135, 280, 370, and 490 cm{sup −1} were included in the fitting procedure. These oscillators represent local maxima of the CeO{sub 2} phonon density of states, which is also calculated using the density functional theory. The lowest energy oscillator represents TA(L)/TA(X) phonon states, which become infrared-active E{sub u} modes at the L and X points of the Brillouin zone (BZ). The second oscillator originates from TO(Γ) phonon states. The oscillator at ∼400 cm{sup −1} originates from Raman mode phonon states, which at the L point of BZ also becomes infrared-active E{sub u} mode. The last oscillator describes phonons with dominantly LO(Γ) infrared mode character. The appearance of phonon density of states related oscillators, instead of single F{sub 2u}infrared-active mode in the far-infrared reflectivity spectra, is a consequence of the nanosized dimension of the CeO{sub 2} particles. The best fit spectra are obtained using the generalized Bruggeman model for inhomogeneous media, which takes into account the nanocrystal volume fraction and the pore shape.

Investigating the optical modes of InxGa1xN alloy and In0.5Ga0.5N/GaN MQW in far-infrared reflectivity spectra

International Nuclear Information System (INIS)

Mirjalili, G.; Amraei, R.

2006-01-01

Optical properties of In x Ga 1 x N alloy and In 0 .5Ga 0 .5N/GaN multi quantum wells have been investigated in the region of far infrared. Far-IR reflectivity spectra of In 0 .5Ga 0 .5N/GaN multi quantum wells on GaAs substrate have been obtained by oblique incidence p- and s- polarization light using effective medium approximation. The spectra and the dielectric functions response give a good information about the phonon and plasmon contribution in doped MQW as well as the mole fraction of compounds in the alloys. The changes in position of optical modes are good tools for measurement of the amount of free carrier and the amount of mole fraction in the samples. During study of In x Ga 1 x N reflectivity spectra, two distinct reststrahl bands with frequency near those of pure InN and GaN were observed over entire composition range. Each band shifts to lower frequencies and decreases in amplitude as the concentration of corresponding compound in alloy decreased. Analysis of dielectric function gives the TO-like and LO-like mode frequencies. The changes in LO mode frequencies, due to coupling of phonon-plasmon, have been observed

High-energy infrared femtosecond pulses generated by dual-chirped optical parametric amplification.

Science.gov (United States)

Fu, Yuxi; Takahashi, Eiji J; Midorikawa, Katsumi

2015-11-01

We demonstrate high-energy infrared femtosecond pulse generation by a dual-chirped optical parametric amplification (DC-OPA) scheme [Opt. Express19, 7190 (2011)]. By employing a 100 mJ pump laser, a signal pulse energy exceeding 20 mJ at a wavelength of 1.4 μm was achieved before dispersion compensation. A total output energy of 33 mJ was recorded. Under a further energy scaling condition, the signal pulse was compressed to an almost transform-limited duration of 27 fs using a fused silica prism compressor. Since the DC-OPA scheme is efficient and energy scalable, design parameters for obtaining 100 mJ level infrared pulses are presented, which are suitable as driver lasers for the energy scaling of high-order harmonic generation with sub-keV photon energy.

Orion star-forming region - far-infrared and radio molecular observations

International Nuclear Information System (INIS)

Thronson, H.A. Jr.; Harper, D.A.; Bally, J.; Dragovan, M.; Mozurkewich, D.; Yerkes Observatory, Williams Bay, WI; ATandT Bell Labs., Holmdel, NJ; Chicago Uni., IL; E. O. Hulburt Center for Space Research, Washington, DC)

1986-01-01

New J = 1-0 CO and far-infrared maps of the Orion star-forming region are presented and discussed. The total infrared luminosity of the Orion star-forming ridge is 250,000 solar luminosities. The material that is emitting strongly at 60 microns is traced and found to be highly centrally concentrated. However, the majority of the extended emission from this region comes from dust that is ultimately heated by the visible Trapezium cluster stars. The luminosity of IRc 2, the most luminous member of the infrared cluster, is estimated to be 40,000-50,000 solar luminosities. A schematic drawing of the Ori MC 1 region is presented. 30 references

650-nJ pulses from a cavity-dumped Yb:fiber-pumped ultrafast optical parametric oscillator

Science.gov (United States)

Lamour, Tobias P.; Reid, Derryck T.

2011-08-01

Sub-250-fs pulses with energies of up to 650 nJ and peak powers up to 2.07 MW were generated from a cavity-dumped optical parametric oscillator, synchronously-pumped at 15.3 MHz with sub-400-fs pulses from an Yb:fiber laser. The average beam quality factor of the dumped output was M2 ~1.2 and the total relative-intensity noise was 8 mdBc, making the system a promising candidate for ultrafast laser inscription of infrared materials.

Far-infrared and CO observations of Cep F: Implications for star formation in Cepheus OB3

International Nuclear Information System (INIS)

Sargent, A.I.; van Duinen, R.J.; Nordh, H.L.; Fridlund, C.V.M.; Aalders, J.W.G.; Beintema, D.

1983-01-01

Observations at 80-μm and 130-μm have revealed a source of far-infrared emission in the Cep F portion of the Cepheus OB3 molecular cloud. Molecular line measurements of this region, at the CO J = 1-0 line frequency, have led to the discovery of two CO maxima. One of these coincides with the new far-infrared source. The other is at least as intense as Cep B, until now considered to be the hottest part of the cloud. There is some evidence to suggest that a second far-infrared source is associated with this hotspot. If the far-infrared emission results from the presence of embedded protostars, their location, relative to the OB association stars and to the other active region, Cep A, requires a reexamination of how stars form in the Cepheus OB3 association

New far infrared images of bright, nearby, star-forming regions

Science.gov (United States)

Harper, D. AL, Jr.; Cole, David M.; Dowell, C. Darren; Lees, Joanna F.; Lowenstein, Robert F.

1995-01-01

Broadband imaging in the far infrared is a vital tool for understanding how young stars form, evolve, and interact with their environment. As the sensitivity and size of detector arrays has increased, a richer and more detailed picture has emerged of the nearest and brightest regions of active star formation. We present data on M 17, M 42, and S 106 taken recently on the Kuiper Airborne Observatory with the Yerkes Observatory 60-channel far infrared camera, which has pixel sizes of 17 in. at 60 microns, 27 in. at 100 microns, and 45 in. at 160 and 200 microns. In addition to providing a clearer view of the complex central cores of the regions, the images reveal new details of the structure and heating of ionization fronts and photodissociation zones where radiation form luminous stars interacts with adjacent molecular clouds.

Enhancement of isobutane refrigerator performance by using far-infrared coating

International Nuclear Information System (INIS)

Hsu, Yu-Chun; Teng, Tun-Ping

2016-01-01

Highlights: • Two-step synthesis method was employed to produce FIRCs. • Emissivity of FIRCs was determined using a FT-IR. • The highest emissivity of FIRMs was MWCNT. • No-load pull-down and 24-h on-load cycling test were performed. • The COP and EF of S2 were greater than those of S1 by 5.92% and 7.89%. - Abstract: This study evaluated the effect on refrigeration performance and feasibility of a far-infrared coating (FIRC) on the condenser of a small isobutane (R-600a) refrigerator. The evaluation was based on the no-load pull-down and 24-h on-load cycling tests. Far-infrared materials and a water-based coating material were mixed using a two-step synthesis method to obtain the FIRC material. Fourier transform infrared spectrometry established that the optimal far-infrared material was a multiwalled carbon nanotube (MWCNT). The results of the no-load pull-down test revealed that the electricity consumption, freezer temperature, and coefficient of performance (COP) of the R-600a refrigerator with MWCNT-FIRC (S2) were lower than those of the refrigerator without MWCNT-FIRC (S1) by 3.39%, 3.61%, and 2.92%, respectively. The results of the 24-h on-load cycling test showed that S2 had a lower electricity consumption, higher slope of pull-down (SPD), higher compression ratio (CR), higher COP, lower duty ratio (DR), and higher energy factor (EF), changing upon those of S1 by −7.05%, 5.66%, 3.24%, 5.92%, −5.63, and 7.89%, respectively. A MWCNT-FIRC on the condenser of an R-600a refrigerator can enhance refrigeration performance and reduce electricity consumption, resulting in energy saving and carbon reduction.

Far-Infrared Absorption of PbSe Nanorods

KAUST Repository

Hyun, Byung-Ryool

2011-07-13

Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical electrostatic model, which is based on the dielectric function of bulk PbSe but without any free-carrier contribution. Good agreement between the measured and calculated spectra indicates that resonances in the local field factors underlie the measured spectra. © 2011 American Chemical Society.

Drying watery wheat grains by far infrared

International Nuclear Information System (INIS)

Suda, K.; Murata, K.; Hara, M.

2004-01-01

Summary A far infrared dryer was experimented to dry wheat grains for high performance and cost reduction. It is more efficient than a circulating dryer reducing drying time by 20% and fuel consumption by 20 - 30%. Whereas it takes more time and more fuel, when the drying rate is set at 1%/h. Moreover, on condition that the average drying rate is lower, it could decrease the rate of green wheat grains up to 3%. But green wheat grains did not disappear at all on the condition

Stimulated transition radiation in the far-infrared

International Nuclear Information System (INIS)

Settakorn, C.; Hernandez, M.; Wiedemann, H.

1997-08-01

Stimulated transition radiation is generated by recycling coherent far-infrared light pulses of transition radiation in a special cavity. The cavity length is designed to be adjustable. At specific intervals the light of a previous bunch coincides at the radiator with the arrival of a subsequent bunch. In this situation, the external electromagnetic field stimulates the emission of higher intensity transition radiation. It is expected that the extracted energy from the cavity will be about 17 times more than would be possible without recycling

Black phosphorus saturable absorber for a diode-pumped passively Q-switched Er:CaF2 mid-infrared laser

Science.gov (United States)

Li, Chun; Liu, Jie; Guo, Zhinan; Zhang, Han; Ma, Weiwei; Wang, Jingya; Xu, Xiaodong; Su, Liangbi

2018-01-01

A multilayer black phosphorus, as a novel two dimensional saturable absorber, has superb saturable absorption properties for a Er:CaF2 solid-state pulse laser. The pulse laser is realized at mid-infrared region with the passively Q-switched technology by a diode-pumping. The high-quality black phosphorus saturable absorber is fabricated by liquid phase exfoliation method. The pulse laser generates the pulses operation with the pulse duration of 954.8 ns, the repetition rate of 41.93 kHz, the pulse energy of 4.25 μJ and the peak power of 4.45 W. Our work demonstrates that black phosphorus could be used as a kind of efficient mid-infrared region optical absorber for ultrafast photonics.

Optical nonlinearities and ultrafast all-optical switching of m-plane GaN in the near-infrared

Energy Technology Data Exchange (ETDEWEB)

Fang, Yu; Zhou, Feng; Yang, Junyi; Yang, Yong [College of Physics, Optoelectronics and Energy, Soochow University, 215006 Suzhou (China); Xiao, Zhengguo; Wu, Xingzhi [Department of Physics, Harbin Institute of Technology, 150001 Harbin (China); Song, Yinglin, E-mail: ylsong@hit.edu.cn [College of Physics, Optoelectronics and Energy, Soochow University, 215006 Suzhou (China); Department of Physics, Harbin Institute of Technology, 150001 Harbin (China)

2015-06-22

We reported a systematic investigation on the three-photon absorption (3PA) spectra and wavelength dispersion of Kerr refraction of bulk m-plane GaN crystal with both polarization E⊥c and E//c by femtosecond Z-scan technique in the near-infrared region from 760 to 1030 nm. Both 3PA spectra and Kerr refraction dispersion were in good agreement with two-band models. The calculated nonlinear figure of merit and measured ultrafast nonlinear refraction dynamics via femtosecond pump-probe with phase object method revealed that m-plane GaN would be a promising candidate for ultrafast all-optical switching and autocorrelation applications at telecommunication wavelengths.

Optimisation of the parameters of a pump chamber for solid-state lasers with diode pumping by the optical boiler method

Energy Technology Data Exchange (ETDEWEB)

Kiyko, V V; Kislov, V I; Ofitserov, E N; Suzdal' tsev, A G [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2015-06-30

A pump chamber of the optical boiler type for solid-state lasers with transverse laser diode pumping is studied theoretically and experimentally. The pump chamber parameters are optimised using the geometrical optics approximation for the pump radiation. According to calculations, the integral absorption coefficient of the active element at a wavelength of 808 nm is 0.75 – 0.8 and the relative inhomogeneity of the pump radiation distribution over the active element volume is 17% – 19%. The developed pump chamber was used in a Nd:YAG laser. The maximum cw output power at a wavelength of 1064 nm was ∼480 W at the optical efficiency up to 19.6%, which agrees with theoretical estimates. (lasers)

The Intrinsic Far-infrared Continua of Type-1 Quasars

Energy Technology Data Exchange (ETDEWEB)

Lyu, Jianwei; Rieke, George H., E-mail: jianwei@email.arizona.edu [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2017-06-01

The range of currently proposed active galactic nucleus (AGN) far-infrared templates results in uncertainties in retrieving host galaxy information from infrared observations and also undermines constraints on the outer part of the AGN torus. We discuss how to test and reconcile these templates. Physically, the fraction of the intrinsic AGN IR-processed luminosity compared with that from the central engine should be consistent with the dust-covering factor. In addition, besides reproducing the composite spectral energy distributions (SEDs) of quasars, a correct AGN IR template combined with an accurate library of star-forming galaxy templates should be able to reproduce the IR properties of the host galaxies, such as the luminosity-dependent SED shapes and aromatic feature strengths. We develop tests based on these expected behaviors and find that the shape of the AGN intrinsic far-IR emission drops off rapidly starting at ∼20 μ m and can be matched by an Elvis et al.-like template with a minor modification. Despite the variations in the near- to mid-IR bands, AGNs in quasars and Seyfert galaxies have remarkably similar intrinsic far-IR SEDs at λ ∼ 20–100 μ m, suggesting a similar emission character of the outermost region of the circumnuclear torus. The variations of the intrinsic AGN IR SEDs among the type-1 quasar population can be explained by the changing relative strengths of four major dust components with similar characteristic temperatures, and there is evidence for compact AGN-heated dusty structures at sub-kiloparsec scales in the far-IR.

BRIEF COMMUNICATIONS: Optically pumped ultraviolet BR2 laser

Science.gov (United States)

Kamrukov, A. S.; Kozlov, N. P.; Protasov, Yu S.; Ushmarov, E. Yu

1989-12-01

A report is given of lasing achieved for the first time in optically pumped molecular bromine (D' 3Π2g→A' 3π2u, λL approx 292 nm). It was pumped by thermal vacuum ultraviolet radiation emitted by plasmadynamic discharges of magnetoplasma compressors, formed directly in the laser active medium. An output energy of ~ 1.1 J was obtained per laser pulse of ~ 5-μs duration from a Br2:Ar approx 1:450 active mixture at a pressure of ~ 4 atm. A comparison was made of the experimental output parameters of optically pumped Br2, I2, and XeF (B-X) lasers when their geometries and excitation energies were identical.

Kinetics of infrared stimulated luminescence from feldspars

DEFF Research Database (Denmark)

Jain, Mayank; Sohbati, Reza; Guralnik, Benny

2015-01-01

thermal and optical, of the infrared stimulated luminescence signal from feldspar. Based on the application of this model, it is concluded that different infra-red stimulated luminescence emissions (UV, blue, yellow and far-red) follow the same kinetics, and, therefore, involve participation of the same...

Effect of rare earth Ce on the far infrared radiation property of iron ore tailings ceramics

Energy Technology Data Exchange (ETDEWEB)

Liu, Jie [Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology), Ministry of Education, Tianjin 300130 (China); Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China); Meng, Junping, E-mail: srlj158@sina.com [Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology), Ministry of Education, Tianjin 300130 (China); Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China); Liang, Jinsheng; Duan, Xinhui [Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology), Ministry of Education, Tianjin 300130 (China); Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China); Huo, Xiaoli [Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China); Tang, Qingguo [Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology), Ministry of Education, Tianjin 300130 (China); Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China)

2015-06-15

Highlights: • Detailed process proposed for preparation of iron ore tailings ceramics. • Replace natural minerals with iron ore tailings as raw materials for preparing functional ceramics. • Impact mechanism of Ce on far infrared ceramics, as well as its optimum addition amounts can be obtained. • Propose a new perspective on considering the mechanism of far infrared radiation. - Abstract: A kind of far infrared radiation ceramics was prepared by using iron ore tailings, CaCO{sub 3} and SiO{sub 2} as main raw materials, and Ce as additive. The result of Fourier transform infrared spectroscopy showed that the sample exhibits excellent radiation value of 0.914 when doping 7 wt.% Ce. Ce{sup 4+} dissolved into iron diopside and formed interstitial solid solution with it sintered at 1150 °C. The oxidation of Fe{sup 2+} to Fe{sup 3+} caused by Ce{sup 4+} led to a decrease of crystallite sizes and enhancement of Mg–O and Fe–O vibration in iron diopside, which consequently improved the far infrared radiation properties of iron ore tailings ceramics.

Estimation of leaf water content from far infrared (2.5-14µm) spectra using continuous wavelet analysis

NARCIS (Netherlands)

Ullah, S.; Skidmore, A.K.; Naeem, M.; Schlerf, M.

2012-01-01

The objective of this study was to estimate leaf water content based on continuous wavelet analysis from the far infrared (2.5 - 14.0 μm) spectra. The entire dataset comprised of 394 far infrared spectra which were divided into calibration (262 spectra) and validation (132 spectra) subsets. The far

Far infrared studies of superconducting V3Si, Nb3Ge and Nb. Final report

International Nuclear Information System (INIS)

Perkowitz, S.

1985-01-01

Far infrared spectroscopy between 10 and 250 cm -1 is an effective probe of superconductivity because typical gap and phonon energies lie in this region. Between 1979 and 1985, this DOE contract supported far infrared research in homogeneous high-T/sub c/ superconductors and in granular superconductors. Results in both areas are summarized in this report

Systems engineering and analysis of electro-optical and infrared systems

CERN Document Server

Arrasmith, William Wolfgang

2015-01-01

Introduction to Electro-optic and Infrared (EO/IR) Systems Engineering?Radiation in the Visible and Infrared Parts of the Electromagnetic SpectrumRadiation SourcesThe Effect of the Atmosphere on Optical PropagationBasic OpticsOptical ModulationThe Detection of Optical RadiationNoise in the Optical Detection ProcessTechnical Performance Measures and Metrics of Optical DetectorsModern Detectors and their Measures of PerformanceThe Effects of Cooling on Optical Detector NoiseSignal and Image ProcessingElectro-Optic and Infrared Systems AnalysisLaser Imaging Systems?Spectral Imaging?LIDAR and LADA

Cosmic far-infrared background at high galactic latitudes

International Nuclear Information System (INIS)

Stecker, F.W.; Puget, J.L.; Fazio, G.G.

1977-01-01

We predict far-infrared background fluxes from various cosmic sources. These fluxes lie near the high-frequency side of the blackbody radiation spectrum. These sources could account for a significant fraction of the background radiation at frequencies above 400 GHz which might be misinterpreted as a ''Comptonization'' distortion of the blackbody radiation. Particular attention is paid to the possible contributions from external galaxies, from rich clusters of galaxies, and from galactic dust emission

Cosmic far-infrared background at high galactic latitudes

International Nuclear Information System (INIS)

Stecker, F.W.; Puget, J.L.; Fazio, G.G.

1976-12-01

Far-infrared background fluxes from various cosmic sources are predicted. These fluxes lie near the high-frequency side of the blackbody radiation spectrum. These sources could account for a significant fraction of the background radiation at frequencies above 400 GHz, which might be misinterpreted as a comptonization distortion of the blackbody radiation. Particular attention is paid to the possible contributions from external galaxies, rich clusters of galaxies and from galactic dust emission

Precision polarization measurements of atoms in a far-off-resonance optical dipole trap

International Nuclear Information System (INIS)

Fang, F.; Vieira, D. J.; Zhao, X.

2011-01-01

Precision measurement of atomic and nuclear polarization is an essential step for beta-asymmetry measurement of radioactive atoms. In this paper, we report the polarization measurement of Rb atoms in an yttrium-aluminum-garnet (YAG) far-off-resonance optical dipole trap. We have prepared a cold cloud of polarized Rb atoms in the YAG dipole trap by optical pumping and achieved an initial nuclear polarization of up to 97.2(5)%. The initial atom distribution in different Zeeman levels is measured by using a combination of microwave excitation, laser pushing, and atomic retrap techniques. The nuclear-spin polarization is further purified to 99.2(2)% in 10 s and maintained above 99% because the two-body collision loss rate between atoms in mixed spin states is greater than the one-body trap loss rate. Systematic effects on the nuclear polarization, including the off-resonance Raman scattering, magnetic field gradient, and background gas collisions, are discussed.

Investigation of a diode-pumped intracavity optical parametric oscillator in pulsed and continuous wave operation

DEFF Research Database (Denmark)

Jensen, Ole Bjarlin; Skettrup, Torben; Balle-Petersen, O.

2001-01-01

Summary form only given. CW and pulsed compact tunable laser sources in the infrared have widespread scientific, medical and industrial applications. Such a laser source can be obtained by use of a diode-pumped intracavity optical parametric oscillator (IOPO). We report on a IOPO based on a Yb......:YAG laser incorporating a periodically poled LiNbO3 (PPLN) crystal inside the laser cavity to take advantage of the high circulating intracavity field. The Yb:YAG crystal is pumped by a reliable 940 nm fibre-coupled diode laser. The IOPO consists of a Yb:YAG crystal coated for HR at 1030 nm, an intracavity...... lens to generate a beam waist in the PPLN crystal, a dichroic mirror to separate the laser and signal fields and two end mirrors...

Far infrared extinction coefficients of minerals of interest for astronomical observations

International Nuclear Information System (INIS)

Hasegawa, H.

1984-01-01

Far infrared extinction coefficients of mineral grains of interest for astronomical observations have been measured. The measured mineral species are: amorphous carbon, high temperature magnesium silicates, hydrous silicates, iron oxides, and amorphous silicates. (author)

Far-infrared and submillimeter spectroscopy of photodissociation regions

International Nuclear Information System (INIS)

Qaiyum, A.

1993-12-01

The physical properties of the galactic and extragalactic photodissociation regions, warm gas components molecular clouds are, generally, derived through the far-infrared (FIR) fine structure and submillimeter line emissions arising out of these regions. In the theoretical studies of these lines the model of Tielens and Hollenbach (herein after referred as TH) are usually employed in which all the opacity is assumed local in escape probability formalism and inward directed photons do not escape. These assumptions are contrary to the observational facts, where most of the lines are found optically thin except OI (63 μm) and low rotational transitions of CO and some other molecules. The optically thin medium will allow the radiation to escape through any face of the region. These observational evidences let us to assume finite parallel plane slab, instead of semi-infinite parallel slab, in which the photons are allowed to escape from both surfaces (back and front). In the present study an attempt has been made to incorporate the two sided escape of photons from the PDRs and to study its effect on the FIR and submillimeter line emission from the PDRs/molecular clouds. Further the present formalism is also employed to study the clumpy PDRs/molecular clouds. The preliminary results show that now serious consequences are found on the thermal and chemical structure of the regions but individual line emissions are modified by differing factors. Particularly at low density and low kinetic temperature the change is substantial but at density greater than the critical density of the line and temperature close to the excitation temperature its effect is almost negligible. An attempt has also been made to study the physical conditions of the M17 region employing the present formalism. (author). 49 refs, 8 figs, 1 tab

Tunable Far Infrared Studies in Support of Stratospheric Measurements

Science.gov (United States)

Chance, Kelly V.; Park, K.; Nolt, I. G.; Evenson, K. M.

2001-01-01

This report summarizes research done under NASA Grant NAG5-4653. The research performed under this grant has been a collaboration between institutions including the Smithsonian Astrophysical Observatory, the National Institute of Standards and Technology, the University of Oregon, and the NASA Langley Research Center. The program has included fully line-resolved measurements of submillimeter and far infrared spectroscopic line parameters (pressure broadening coefficients and their temperature dependences, and line positions) for the analysis of field measurements of stratospheric constituents, far infrared database improvements, and studies for improved satellite measurements of the Earth's atmosphere. This research program is designed to enable the full utilization of spectra obtained in far infrared/submillimeter field measurements, such as FIRS-2, FILOS, IBEX, SLS, EosMLS, and proposed European Space Agency measurements of OH (e.g., PIRAMHYD and SFINX) for the retrieval of accurate stratospheric altitude profiles of key trace gases involved in ozone layer photochemistry. For the analysis of the spectra obtained in the stratosphere from far infrared measurements it is necessary to have accurate values of the molecular parameters (line positions, strengths, and pressure broadening coefficients) for the measured molecules and for possible interfering species. Knowledge of line positions is in increasingly good shape, with some notable exceptions. The increase in position information includes research that has been performed in the present program of research on HO2, H2O, H2O2, O3, HCl, HF, HBr, HI, CO, OH, and ClO. Examples where further line position studies are necessary include hot band and minor isotopomer lines of some of the major trace species (H2O, O3) and normal lines of some triatomic and larger molecules (NO2). Knowledge of strengths is in generally good shape, since most of the lines are from electric dipole transitions whose intensities are well

Microfabricated optically pumped magnetometer arrays for biomedical imaging

Science.gov (United States)

Perry, A. R.; Sheng, D.; Krzyzewski, S. P.; Geller, S.; Knappe, S.

2017-02-01

Optically-pumped magnetometers have demonstrated magnetic field measurements as precise as the best superconducting quantum interference device magnetometers. Our group develops miniature alkali atom-based magnetic sensors using microfabrication technology. Our sensors do not require cryogenic cooling, and can be positioned very close to the sample, making these sensors an attractive option for development in the medical community. We will present our latest chip-scale optically-pumped gradiometer developed for array applications to image magnetic fields from the brain noninvasively. These developments should lead to improved spatial resolution, and potentially sensitive measurements in unshielded environments.

Push-pull optical pumping of pure superposition states

International Nuclear Information System (INIS)

Jau, Y.-Y.; Miron, E.; Post, A.B.; Kuzma, N.N.; Happer, W.

2004-01-01

A new optical pumping method, 'push-pull pumping', can produce very nearly pure, coherent superposition states between the initial and the final sublevels of the important field-independent 0-0 clock resonance of alkali-metal atoms. The key requirement for push-pull pumping is the use of D1 resonant light which alternates between left and right circular polarization at the Bohr frequency of the state. The new pumping method works for a wide range of conditions, including atomic beams with almost no collisions, and atoms in buffer gases with pressures of many atmospheres

Optical--microwave pumping of alkali atoms and population capture

International Nuclear Information System (INIS)

Aleksandrov, E.B.; Vershovskii, A.K.

1985-01-01

The steady-state distribution of the populations of the hyperfine sublevels of the ground state of alkali atoms is calculated for the case in which the atoms are subjected to a spectrally selective optical pumping on 2 S 1 /sub // 2 -- 2 P/sub 1/2,3/2/ transitions and a simultaneous pumping by microwave fields which are at resonance with transitions in the hyperfine structure of the ground state, F = 2, M/sub F/ = +- 2, +- 1bold-arrow-left-rightF = 1, M/sub F/ = +- 1. The addition of the microwave pumping is shown to substantially increase the population difference for the O--O transition in the hyperfine structure. During selective optical pumping of the F = 1 level, the population inversion which can be achieved for the O--O transition is limited by the effect of population capture. This capture can be eliminated by using incoherent microwave fields. The quality factor of the O--O resonance is calculated as a function of the parameters of the pump. The outlook for the use of composite pumping in frequency-stabilization systems is discussed

Infrared and optical observations of Nova Mus 1983

International Nuclear Information System (INIS)

Whitelock, P.A.; Carter, B.S.; Feast, M.W.; Glass, I.S.; Laney, D.; Menzies, J.W.

1984-01-01

Extensive optical (UBVRI) and infrared (JHKL) photometry of Nova Mus 1983 obtained over a period of 300 days is tabulated. Infrared and optical spectra are described. Although by classical definition this was a fast nova its later development was slower than for typical objects of this class. Surprisingly the development of infrared thermal dust emission did not occur. Throughout the period covered, the infrared emission was characteristic of a bound-free plus free-free plasma continuum with emission lines. (author)

Far-infrared ferroelectric soft mode spectroscopy on thin films

Czech Academy of Sciences Publication Activity Database

Petzelt, Jan; Ostapchuk, Tetyana

2001-01-01

Roč. 249, 1-2 (2001), s. 81-88 ISSN 0015-0193 R&D Projects: GA ČR GA202/98/1282; GA AV ČR IAA1010918; GA MŠk OC 514.10 Institutional research plan: CEZ:AV0Z1010914 Keywords : far-infrared spectroscopy * soft mode * dielectric spectra * permitivity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.471, year: 2001

Safari: instrument design of the far-infrared imaging spectrometer for spica

Science.gov (United States)

Jellema, W.; Pastor, C.; Naylor, D.; Jackson, B.; Sibthorpe, B.; Roelfsema, P.

2017-11-01

The next great leap forward in space-based far-infrared astronomy will be made by the Japanese-led SPICA mission, which is anticipated to be launched late 2020's as the next large astrophysics mission of JAXA, in partnership with ESA and with key European contributions. Filling in the gap between JWST and ALMA, the SPICA mission will study the evolution of galaxies, stars and planetary systems. SPICA will utilize a deeply cooled 3m-class telescope, provided by European industry, to realize zodiacal background limited performance, high spatial resolution and large collecting area. Making full advantage of the deeply cooled telescope (architecture. We will describe the reference design of the SAFARI focal- plane unit, the implementation of the various optical instrument functions designed around the central large-stroke FTS system, the photometric band definition and out-of-band filtering by quasioptical elements, the control of straylight, diffraction and thermal emission in the long-wavelength limit, and how we interface to the large-format FPA arrays at one end and the SPICA telescope assembly at the other end. We will briefly discuss the key performance drivers with special emphasis on the optical techniques adopted to overcome issues related to very low background operation of SAFARI. A summary and discussion of the expected instrument performance and an overview of the astronomical capabilities finally conclude the paper.

Advancing toward far-infrared interferometry in space through coordinated international efforts

NARCIS (Netherlands)

Leisawitz, D.; Baryshev, A.; Griffin, M. J.; Helmich, F. P.; Ivison, R. J.; Rinehart, S. A.; Savini, G.; Shibai, H.

2013-01-01

The international far-infrared astrophysics community is eager to follow up Spitzer and Herschel observations with sensitive, high-resolution imaging and spectroscopy, for such measurements are needed to understand merger-driven star formation, Active Galactic Nuclei, chemical enrichment in

The Far Infrared Lines of OH as Molecular Cloud Diagnostics

Science.gov (United States)

Smith, Howard A.

2004-01-01

Future IR missions should give some priority to high resolution spectroscopic observations of the set of far-IR transitions of OH. There are 15 far-IR lines arising between the lowest eight rotational levels of OH, and ISO detected nine of them. Furthermore, ISO found the OH lines, sometimes in emission and sometimes in absorption, in a wide variety of galactic and extragalactic objects ranging from AGB stars to molecular clouds to active galactic nuclei and ultra-luminous IR galaxies. The ISO/LWS Fabry-Perot resolved the 119 m doublet line in a few of the strong sources. This set of OH lines provides a uniquely important diagnostic for many reasons: the lines span a wide wavelength range (28.9 m to 163.2 m); the transitions have fast radiative rates; the abundance of the species is relatively high; the IR continuum plays an important role as a pump; the contribution from shocks is relatively minor; and, not least, the powerful centimeter-wave radiation from OH allows comparison with radio and VLBI datasets. The problem is that the large number of sensitive free parameters, and the large optical depths of the strongest lines, make modeling the full set a difficult job. The SWAS montecarlo radiative transfer code has been used to analyze the ISO/LWS spectra of a number of objects with good success, including in both the lines and the FIR continuum; the DUSTY radiative transfer code was used to insure a self-consistent continuum. Other far IR lines including those from H2O, CO, and [OI] are also in the code. The OH lines all show features which future FIR spectrometers should be able to resolve, and which will enable further refinements in the details of each cloud's structure. Some examples are given, including the case of S140, for which independent SWAS data found evidence for bulk flows.

The Far-Infrared Emission Line and Continuum Spectrum of the Seyfert Galaxy NGC 1068

Science.gov (United States)

Spinoglio, Luigi; Smith, Howard A.; Gonzalez-Alfonso, Eduardo; Fisher, Jacqueline

2005-01-01

We report on the analysis of the first complete far-infrared spectrum (43-197 microns) of the Seyfert 2 galaxy NGC 1068 as observed with the Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO). In addition to the 7 expected ionic fine structure emission lines, the OH rotational lines at 79, 119 and 163 microns were all detected in emission, which is unique among galaxies with full LWS spectra, where the 119 micron line, where detected, is always in absorption. The observed line intensities were modelled together with IS0 Short Wavelength Spectrometer (SWS) and optical and ultraviolet line intensities from the literature, considering two independent emission components: the AGN component and the starburst component in the circumnuclear ring of approximately 3kpc in size. Using the UV to mid-IR emission line spectrum to constrain the nuclear ionizing continuum, we have confirmed previous results: a canonical power-law ionizing spectrum is a poorer fit than one with a deep absorption trough, while the presence of a big blue bump is ruled out. Based on the instantaneous starburst age of 5 Myr constrained by the Br gamma equivalent width in the starburst ring, and starburst synthesis models of the mid- and far-infrared fine-structure line emission, a low ionization parameter (U=10(exp -3.5)) and low densities (n=100 cm (exp -3)) are derived. Combining the AGN and starburst components, we succeed in modeling the overall UV to far-IR atomic spectrum of SGC 1068, reproducing the line fluxes to within a factor 2.0 on average with a standard deviation of 1.4. The OH 119 micron emission indicates that the line is collisionally excited, and arises in a warm and dense region. The OH emission has been modeled using spherically symmetric, non-local, non-LTE radiative transfer models. The models indicate that the bulk of the emission arises from the nuclear region, although some extended contribution from the starburst is not ruled out. The OH abundance

The OPTICON technology roadmap for optical and infrared astronomy

Science.gov (United States)

Cunningham, Colin; Melotte, David; Molster, Frank

2010-07-01

The Key Technology Network (KTN) within the OPTICON programme has been developing a roadmap for the technology needed to meet the challenges of optical and infrared astronomy over the next few years, with particular emphasis on the requirements of Extremely Large Telescopes. The process and methodology so far will be described, along with the most recent roadmap. The roadmap shows the expected progression of ground-based astronomy facilities and the technological developments which will be required to realise these new facilities. The roadmap highlights the key stages in the development of these technologies. In some areas, such as conventional optics, gradual developments in areas such as light-weighting of optics will slowly be adopted into future instruments. In other areas, such as large area IR detectors, more rapid progress can be expected as new processing techniques allow larger and faster arrays. Finally, other areas such as integrated photonics have the potential to revolutionise astronomical instrumentation. Future plans are outlined, in particular our intention to look at longer term development and disruptive technologies.

Manifestation of surface phonons in far infrared reflectivity of diamond-type semiconductors

Energy Technology Data Exchange (ETDEWEB)

Perez-Sanchez, F.L.; Perez-Rodriguez, F. [Instituto de Fisica, Universidad Autonoma de Puebla, Apdo. Post. J-48, Puebla, Pue. 72570 (Mexico)

2004-11-01

The coupling of surface phonons with light at (001) surfaces of diamond-structure crystals and its manifestation in far-infrared anisotropy spectra are theoretically studied. We apply the adiabatic bond charge model to describe short-range mechanical interactions together with long-range Coulomb forces and radiation fields, and we solve the corresponding system of coupled equations for the electromagnetic field and the lattice vibrations. We calculate far-infrared normal reflectance spectra of (001) surfaces of semi-infinite diamond-type crystals. In particular, we analyse reflectance spectra for the Si(001) (2 x 1) surface, which exhibit a resonance structure associated with the excitation of surface phonon modes. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Controlling the optical bistability and multistability in a two-level pumped-probe system

International Nuclear Information System (INIS)

Mahmoudi, Mohammad; Sahrai, Mostafa; Masoumeh Mousavi, Seyede

2010-01-01

We study the behavior of the optical bistability (OB) and multistability (OM) in a two-level pumped-probe atomic system by means of a unidirectional ring cavity. We show that the optical bistability in a two-level atomic system can be controlled by adjusting the intensity of the pump field and the detuning between two fields. We find that applying the pumping field decreases the threshold of the optical bistability.

Density functional theory for prediction of far-infrared vibrational frequencies: molecular crystals of astrophysical interest

Science.gov (United States)

Ennis, C.; Auchettl, R.; Appadoo, D. R. T.; Robertson, E. G.

2017-11-01

Solid-state density functional theory code has been implemented for the structure optimization of crystalline methanol, acetaldehyde and acetic acid and for the calculation of infrared frequencies. The results are compared to thin film spectra obtained from low-temperature experiments performed at the Australian Synchrotron. Harmonic frequency calculations of the internal modes calculated at the B3LYP-D3/m-6-311G(d) level shows higher deviation from infrared experiment than more advanced theory applied to the gas phase. Importantly for the solid-state, the simulation of low-frequency molecular lattice modes closely resembles the observed far-infrared features after application of a 0.92 scaling factor. This allowed experimental peaks to be assigned to specific translation and libration modes, including acetaldehyde and acetic acid lattice features for the first time. These frequency calculations have been performed without the need for supercomputing resources that are required for large molecular clusters using comparable levels of theory. This new theoretical approach will find use for the rapid characterization of intermolecular interactions and bonding in crystals, and the assignment of far-infrared spectra for crystalline samples such as pharmaceuticals and molecular ices. One interesting application may be for the detection of species of prebiotic interest on the surfaces of Kuiper-Belt and Trans-Neptunian Objects. At such locations, the three small organic molecules studied here could reside in their crystalline phase. The far-infrared spectra for their low-temperature solid phases are collected under planetary conditions, allowing us to compile and assign their most intense spectral features to assist future far-infrared surveys of icy Solar system surfaces.

Efficient Mid-Infrared Supercontinuum Generation in Tapered Large Mode Area Chalcogenide Photonic Crystal Fibers

DEFF Research Database (Denmark)

Petersen, Christian Rosenberg; Engelsholm, Rasmus Dybbro; Markos, Christos

2017-01-01

Mid-infrared supercontinuum spanning from 1.8-9  μm with an output power of 41.5 mW is demonstrated by pumping tapered large mode area chalcogenide photonic crystal fibers using a 4 μm optical parametric source.......Mid-infrared supercontinuum spanning from 1.8-9  μm with an output power of 41.5 mW is demonstrated by pumping tapered large mode area chalcogenide photonic crystal fibers using a 4 μm optical parametric source....

Ischemia monitoring in off-pump coronary artery bypass surgery using intravascular near-infrared spectroscopy

Directory of Open Access Journals (Sweden)

Zerkowski Hans-Reinhard

2006-05-01

Full Text Available Abstract Background In off-pump coronary artery bypass surgery, manipulations on the beating heart can lead to transient interruptions of myocardial oxygen supply, which can generate an accumulation of oxygen-dependent metabolites in coronary venous blood. The objective of this study was to evaluate the reliability of intravascular near-infrared spectroscopy as a monitoring method to detect possible ischemic events in off-pump coronary artery bypass procedures. Methods In 15 elective patients undergoing off-pump myocardial revascularization, intravascular near-infrared spectroscopic analysis of coronary venous blood was performed. NIR signals were transferred through a fiberoptic catheter for signal emission and collection. For data analysis and processing, a miniature spectrophotometer with multivariate statistical package was used. Signal acquisition and analysis were performed before and after revascularization. Spectroscopic data were compared with hemodynamic parameters, electrocardiogram, transesophageal echocardiography and laboratory findings. Results A conversion to extracorporeal circulation was not necessary. The mean number of grafts per patient was 3.1 ± 0.6. An intraoperative myocardial ischemia was not evident, as indicated by electrocardiogram and transesophageal echocardiography. Continuous spectroscopic analysis showed reproducible absorption spectra of coronary sinus blood. Due to uneventful intraoperative courses, clear ischemia-related changes could be detected in none of the patients. Conclusion Our initial results show that intravascular near-infrared spectroscopy can reliably be used for an online intraoperative ischemia monitoring in off-pump coronary artery bypass surgery. However, the method has to be further evaluated and standardized to determine the role of spectroscopy in off-pump coronary artery bypass surgery.

Far-infrared properties of sol-gel derived PbZr0.52Ti0.48O3 thin films on Pt-coated substrates

International Nuclear Information System (INIS)

Kafadaryan, E A; Hovsepyan, R K; Khachaturova, A A; Aghamalyan, N R; Shirinyan, G O; Manukyan, A L; Vardanyan, R S; Hayrapetyan, A G; Grigoryan, S G; Vardanyan, E S

2003-01-01

Polycrystalline tetragonal PbZr 0.52 Ti 0.48 O 3 (PZT) thin films have been deposited on the nickel and (111) platinum coated (110) sapphire substrates by the sol-gel method. Optical properties of the PZT thin films were studied using far-infrared reflectivity spectroscopy in the 200-10 000 cm -1 frequency range at 300 K. The frequency dependence of the optical characteristics (σ, ε, -Im ε -1 ) of the films were calculated by the Kramers-Kronig transformation of the reflectivity spectra and analysed by the Drude-Lorentz model. The frequency dependence of the optical conductivity, σ(ω), of the PZT films deposited on platinum coated sapphire is well described by the free-carrier term and an overdamped mid-infrared component. Sapphire/Pt/PZT structures reveal semiconductor properties (effective carrier concentration N/m* is up to 10 20 cm -3 , plasma minimum is located near 3000 cm -1 ). This effect can be related to the favourable influence of the platinum electrode on the charge carrier density at Pt/PZT contact and formation of the interfacial conductive layer

Optically pumped polarized 23Na vapor target for use in polarized ion source. Technical progress report

International Nuclear Information System (INIS)

Anderson, L.W.

1984-01-01

We are currently measuring relaxation times in an optically pumped 23 Na vapor target. Our research is directed toward improvements in the optically pumped Na vapor targets used for the production of polarized H - ions. In this progress report we review the properties of the optically pumped polarized H - ion source and especially the optically pumped Na vapor target employed in this source as well as discussing the progress of our research on relaxation times in an optically pumped Na vapor target. 30 references, 6 figures, 3 tables

Optimizations of spin-exchange relaxation-free magnetometer based on potassium and rubidium hybrid optical pumping

International Nuclear Information System (INIS)

Fang, Jiancheng; Wang, Tao; Li, Yang; Zhang, Hong; Zou, Sheng

2014-01-01

The hybrid optical pumping atomic magnetometers have not realized its theoretical sensitivity, the optimization is critical for optimal performance. The optimizations proposed in this paper are suitable for hybrid optical pumping atomic magnetometer, which contains two alkali species. To optimize the parameters, the dynamic equations of spin evolution with two alkali species were solved, whose steady-state solution is used to optimize the parameters. The demand of the power of the pump beam is large for hybrid optical pumping. Moreover, the sensitivity of the hybrid optical pumping magnetometer increases with the increase of the power density of the pump beam. The density ratio between the two alkali species is especially important for hybrid optical pumping magnetometer. A simple expression for optimizing the density ratio is proposed in this paper, which can help to determine the mole faction of the alkali atoms in fabricating the hybrid cell before the cell is sealed. The spin-exchange rate between the two alkali species is proportional to the saturated density of the alkali vapor, which is highly dependent on the temperature of the cell. Consequently, the sensitivity of the hybrid optical pumping magnetometer is dependent on the temperature of the cell. We proposed the thermal optimization of the hybrid cell for a hybrid optical pumping magnetometer, which can improve the sensitivity especially when the power of the pump beam is low. With these optimizations, a sensitivity of approximately 5 fT/Hz 1/2 is achieved with gradiometer arrangement

Optical Pumping of Molecular Gases

Science.gov (United States)

1976-04-01

ser emission ott a The typical experimental apparatus is shown i.- Fig. *series of green and yellow molecular B-X’-basnd transi- 2. For B-bantd optical...with A, at 0. 473 pim and that Na2 may operate as a flash -lamp -pumped laser X,... at 0. 54 umn the Doppler widths are AwD - 12.42 source with buffer

High resolution far-infrared survey of A section of the galactic plane. I. The nature of the sources

International Nuclear Information System (INIS)

Jaffe, D.T.; Stier, M.T.; Fazio, G.G.

1982-01-01

We have surveyed a 7.5 deg 2 portion of the galactic plane between l/sup II/ = 10 0 and l/sup II/ = 16 0 at 70 μm with a 1' beam. We present far-infrared, radio continuum, and 12 CO and 13 CO line observations of the 42 far-infrared sources in the survey region. The sources range in luminosity from 4 x 10 3 to 3 x 10 6 L/sub sun/. Most are associated with 12 CO peaks. More than half of the sources have associated H 2 O maser emission. Half have associated radio continuum emission at a limit of 100 mJy. Eight sources have radio emission at weaker levels. In a number of cases, the far-infrared source is smaller than its associated radio source. This difference can be explained in the context of the ''blister'' picture of H II regions. One group of sources emits many fewer Lyman continuum photons than expected, given the far-infrared luminosities. We examine a number of possible reasons for this and conclude that the most reasonable explanation is that clusters of early type stars rather than single stars excite the far-infrared sources. We examine the energetics in the molecular clouds surrounding the infrared sources and conclude that the sources could supply the energy to explain the observed temperature structure and velocity field in the molecular gas

Optical pumping-assisted electromagnetically induced transparency

International Nuclear Information System (INIS)

Jiang Wei; Chen Qunfeng; Zhang Yongsheng; Guo, G.-C.

2006-01-01

In this paper we report an observation of the two-photon absorption in a four-level system in hot 87 Rb vapor based on the proposal of Harris and Yamamoto [Phys. Rev. Lett. 81, 3611 (1998)]. We show that this effect is reduced in hot atoms due to the non-Doppler-free nature of this scheme. Then we report a phenomenon that could be used in the same application of Harris and Yamamoto. The main result is a great enhancement of electromagnetically induced transparency (EIT) effect in hot 87 Rb vapor caused by optical pumping. We find that when the single photon detuning is near zero the EIT signal is dramatically enhanced by an optical pumping field. More interestingly when the single photon detuning is larger the signal can be changed from a sharp Raman peak to a sharp EIT dip. The full width at half maximum of the peak and dip are narrow and subnatural

Vacuum variable-angle far-infrared ellipsometer

Science.gov (United States)

Friš, Pavel; Dubroka, Adam

2017-11-01

We present the design and performance of a vacuum far-infrared (∼50-680 cm-1) ellipsometer with a rotating analyser. The system is based on a Fourier transform spectrometer, an in-house built ellipsometer chamber and a closed-cycle bolometer. The ellipsometer chamber is equipped with a computer controlled θ-2θ goniometer for automated measurements at various angles of incidence. We compare our measurements on SrTiO3 crystal with the results acquired above 300 cm-1 with a commercially available ellipsometer system. After the calibration of the angle of incidence and after taking into account the finite reflectivity of mirrors in the detector part we obtain a very good agreement between the data from the two instruments. The system can be supplemented with a closed-cycle He cryostat for measurements between 5 and 400 K.

FIRBACK Far Infrared Survey with ISO: Data Reduction, Analysis and First Results

OpenAIRE

Dole, Herve; Lagache, Guilaine; Puget, Jean-Loup; Gispert, Richard; Aussel, H.; Bouchet, F. R.; Ciliegi, C.; Clements, D. L.; Cesarsky, C.; Desert, F-X; Elbaz, D.; Franceschini, A.; Guiderdoni, B.; Harwit, M.; Laureijs, R.

1999-01-01

FIRBACK is one of the deepest cosmological surveys performed in the far infrared, using ISOPHOT. We describe this survey, its data reduction and analysis. We present the maps of fields at 175 microns. We point out some first results: source identifications with radio and mid infrared, and source counts at 175 microns. These two results suggest that half of the FIRBACK sources are probably at redshifts greater than 1. We also present briefly the large follow-up program.

Photon-Counting Microwave Kinetic Inductance Detectors (MKIDs) for High Resolution Far-Infrared Spectroscopy

Data.gov (United States)

National Aeronautics and Space Administration — We are developing ultrasensitive Microwave Kinetic Inductance Detectors (MKIDs) for high resolution far-infrared spectroscopy applications, with a long-term goal of...

Two-crystal mid-infrared optical parametric oscillator for absorption and dispersion dual-comb spectroscopy.

Science.gov (United States)

Jin, Yuwei; Cristescu, Simona M; Harren, Frans J M; Mandon, Julien

2014-06-01

We present a femtosecond optical parametric oscillator (OPO) containing two magnesium-doped periodically poled lithium niobate crystals in a singly resonant ring cavity, pumped by two mode-locked Yb-fiber lasers. As such, the OPO generates two idler combs (up to 220 mW), covering a wavelength range from 2.7 to 4.2 μm, from which a mid-infrared dual-comb Fourier transform spectrometer is constructed. By detecting the heterodyning signal between the two idler beams a full broadband spectrum of a molecular gas can be observed over 250  cm(-1) within 70 μs with a spectral resolution of 15 GHz. The absorption and dispersion spectra of acetylene and methane have been measured around 3000  cm(-1), indicating that this OPO represents an ideal broadband mid-infrared source for fast chemical sensing.

Time-resolved far-infrared experiments at the National Synchrotron Light Source. Final report

International Nuclear Information System (INIS)

Tanner, D.B.; Reitze, D.H.; Carr, G.L.

1999-01-01

A facility for time-resolved infrared and far-infrared spectroscopy has been built and commissioned at the National Synchrotron Light Source. This facility permits the study of time dependent phenomena over a frequency range from 2-8000cm -1 (0.25 meV-1 eV). Temporal resolution is approximately 200 psec and time dependent phenomena in the time range out to 100 nsec can be investigated

Far infrared spectroscopy of high-Tc superconductors at the National Synchrotron Light Source

International Nuclear Information System (INIS)

Perkowitz, S.; Williams, G.P.

1989-01-01

This paper reports the first far infrared transmission spectra for micron-thick films of high-T c rare-earth superconductors such as DyBaCuO, with implications for the superconducting gap. Spectra were obtained at Brookhaven's National Synchrotron Light Source, a new high-intensity, broad-band millimeter to infrared source. The National Synchrotron Light Source at Brookhaven National Laboratory, known for powerful X-ray and UV output, is also a high-intensity (10 to 1000 times above a black body), high-brightness (intensity per solid angle), broad-band, picosecond, millimeter to infrared source. These features make it valuable for far-infrared condensed matter experiments, especially those in highly absorbing or extremely small systems. A first application has been to measure very small infrared transmissions through thick bulk-like high-T c superconducting films. Preliminary measurements through films of the conventional superconductor Nb 3 Ge established techniques. These were followed by the first measurements (to the author's knowledge) through micron-thick films of high-T c rare-earth superconductors such as DyBaCuO over 10-300 cm -1 , which includes the superconducting gap according to BCS or moderately strong-coupled theory. The authors discuss the transmission evidence bearing on the existence of a gap and other important features of high-T c superconductors, and describe the synchrotron and instrumentation features which make possible these unusual measurements

Extending pure luminosity evolution models into the mid-infrared, far-infrared and submillimetre

Science.gov (United States)

Hill, Michael D.; Shanks, Tom

2011-07-01

Simple pure luminosity evolution (PLE) models, in which galaxies brighten at high redshift due to increased star formation rates (SFRs), are known to provide a good fit to the colours and number counts of galaxies throughout the optical and near-infrared. We show that optically defined PLE models, where dust reradiates absorbed optical light into infrared spectra composed of local galaxy templates, fit galaxy counts and colours out to 8 μm and to at least z≈ 2.5. At 24-70 μm, the model is able to reproduce the observed source counts with reasonable success if 16 per cent of spiral galaxies show an excess in mid-IR flux due to a warmer dust component and a higher SFR, in line with observations of local starburst galaxies. There remains an underprediction of the number of faint-flux, high-z sources at 24 μm, so we explore how the evolution may be altered to correct this. At 160 μm and longer wavelengths, the model fails, with our model of normal galaxies accounting for only a few percent of sources in these bands. However, we show that a PLE model of obscured AGN, which we have previously shown to give a good fit to observations at 850 μm, also provides a reasonable fit to the Herschel/BLAST number counts and redshift distributions at 250-500 μm. In the context of a ΛCDM cosmology, an AGN contribution at 250-870 μm would remove the need to invoke a top-heavy IMF for high-redshift starburst galaxies.

Phosphate-core silica-clad Er/Yb-doped optical fiber and cladding pumped laser.

Science.gov (United States)

Egorova, O N; Semjonov, S L; Velmiskin, V V; Yatsenko, Yu P; Sverchkov, S E; Galagan, B I; Denker, B I; Dianov, E M

2014-04-07

We present a composite optical fiber with a Er/Yb co-doped phosphate-glass core in a silica glass cladding as well as cladding pumped laser. The fabrication process, optical properties, and lasing parameters are described. The slope efficiency under 980 nm cladding pumping reached 39% with respect to the absorbed pump power and 28% with respect to the coupled pump power. Due to high doping level of the phosphate core optimal length was several times shorter than that of silica core fibers.

Optically pumped ultraviolet and infrared lasers driven by exploding metal films and wires

International Nuclear Information System (INIS)

Jones, C.R.; Ware, K.D.

1983-01-01

The 342-nm molecular iodine and 1315-nm atomic iodine lasers have been optically pumped by intense light from exploding-metal-film and exploding-wire discharges. Brightness temperatures for the exploding-film discharges were approx. 25,000 K and for the wire discharges were approx. 30,000 K. For the I 2 laser the 3.5-cm-diameter by 40-cm-long pumped volume lies adjacent to the wire or film of the same length. Pressures of 1 to 6 torr I 2 and 1 to 3 atm SF, CF 4 , or Ar were used in the stainless-steel cell. Using 20-μF capacitance charged to 40 kV, a 0.25-mm tungsten wire, 3-torr I 2 , and a 2-atm SF 6 , an energy of 2 J was obtained from the laser in a pulse of 8-μs duration. The specific output energy was 7 J/l. Substitution of a cylindrical Al film for the wire, under otherwise similar conditions, led to a X10 output energies and efficiencies were obtained with similar input energy. An output pulse of 12 J and 12-μs duration was measured for a specific output energy of 18 J/l. A laser energy of 110 J in a 20-us-long pulse has been measured from atomic iodine using a wire discharge along the axis of a larger cell. The active volume available was 20 cm in diameter and 80 cm in length. Input energy was 32 kJ. In similar measurements using a cylindrical Al film for discharge initiation, the measured output energy was 40 J

Far-infrared irradiation drying behavior of typical biomass briquettes

International Nuclear Information System (INIS)

Chen, N.N.; Chen, M.Q.; Fu, B.A.; Song, J.J.

2017-01-01

Infrared radiation drying behaviors of four typical biomass briquettes (populus tomentosa leaves, cotton stalk, spent coffee grounds and eucalyptus bark) were investigated based on a lab-scale setup. The effect of radiation source temperatures (100–200 °C) on the far-infrared drying kinetics and heat transfer of the samples was addressed. As the temperature went up from 100 °C to 200 °C, the time required for the four biomass briquettes drying decreased by about 59–66%, and the average values of temperature for the four biomass briquettes increased by about 33–39 °C, while the average radiation heat transfer fluxes increased by about 3.3 times (3.7 times only for the leaves). The specific energy consumptions were 0.622–0.849 kW h kg"−"1. The Modified Midilli model had the better representing for the moisture ratio change of the briquettes. The values of the activation energy for the briquettes in the first falling rate stage were between 20.35 and 24.83 kJ mol"−"1, while those in the second falling rate stage were between 17.89 and 21.93 kJ mol"−"1. The activation energy for the eucalyptus bark briquette in two falling rate stages was the least one, and that for the cotton stalk briquette was less than that for the rest two briquettes. - Highlights: • Far infrared drying behaviors of four typical biomass briquettes were addressed. • The effect of radiation source temperatures on IR drying kinetics was stated. • Radiation heat transfer flux between the sample and heater was evaluated. • Midilli model had the better representing for the drying process of the samples.

Solid state spectroscopy by using of far-infrared synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Nanba, Takao [Kobe Univ. (Japan). Faculty of Science

1996-07-01

If the spectroscopic system corresponding to the wavelength region required for experiment is installed, the light source with continuous wavelength is to be obtainable by synchrotron radiation. This report is that of the research on solid state spectroscopy using the ordinary incoherent synchrotron radiation which is obtained from the deflection electromagnet parts of electron storage ring. At present in the world, the facilities which can be utilized in far-infrared spectroscopy region are five, including the UVSOR of Molecular Science Research Institute in Japan. The optical arrangement of the measuring system of the UVSOR is shown. The spectrum distribution of the light passing through the pinholes with different diameter in the place of setting samples was compared in case of the UVSOR and a high pressure mercury lamp, and it was shown that synchrotron radiation has high luminance. The researches on solid state spectroscopy carried out in the above mentioned five facilities are enumerated. In this paper, the high pressure spectroscopic experiment which has been carried out at the UVSOR is reported. The observation of the phase transition of fine particles and the surface phonons of fine particles are described. As fine particle size became smaller, the critical pressure at which phase transition occurred was high. (K.I.)

Atomic oxygen fine-structure splittings with tunable far-infrared spectroscopy

Science.gov (United States)

Zink, Lyndon R.; Evenson, Kenneth M.; Matsushima, Fusakazu; Nelis, Thomas; Robinson, Ruth L.

1991-01-01

Fine-structure splittings of atomic oxygen (O-16) in the ground state have been accurately measured using a tunable far-infrared spectrometer. The 3P0-3pl splitting is 2,060,069.09 (10) MHz, and the 3Pl-3P2 splitting is 4,744,777.49 (16) MHz. These frequencies are important for measuring atomic oxygen concentration in earth's atmosphere and the interstellar medium.

A dual-optically-pumped polarized negative deuterium ion source

International Nuclear Information System (INIS)

Kinsho, M.; Mori, Y.; Ikegami, K.; Takagi, A.

1994-01-01

An optically pumped polarized H - source (OPPIS), which is based on the charge exchange between H + ions and electron-spin-polarized alkali atoms has been developed at KEK. Just by applying this scheme to a deuteron beam, it is difficult to obtain a highly vector polarized deuteron beam. To obtain highly vector polarized D - ions, we have developed a 'dual optical pumping type' of polarized D - source. With this scheme, a 100% vector nuclear-spin polarization for D - ions is possible in principle. In a preliminary experiment, a 60% of vector nuclear-spin polarized D - ions was obtained. (author)

Far-infrared observations of M17: The interaction of an H II region with a molecular cloud

International Nuclear Information System (INIS)

Gatley, I.; Becklin, E.E.; Sellgren, K.; Werner, M.W.

1979-01-01

The central 15' of the M17 H II region--molecular cloud complex has been mapped with 1' resolution simultaneously at 30, 50, and 100 μm. The data suggest that the bulk of the luminosity radiated in the far-infrared is supplied by the exciting stars of the H II region; the far-infrared radiation is thermal emission from dust grains located chiefly outside the ionized gas. Large-scale systematic gradients in both the temperature and the column density of the dust are seen across the source. The appearance of the source in the far-infrared reflects the markedly nonuniform distribution of matter around the exciting stars; the H II region is bounded by the molecular cloud to the southwest. The core of the molecular cloud is heated primarily by infrared radiation from dust within and adjacent to the H II region; no evidence is seen for substantial luminosity sources embedded within the molecular cloud

Metastability-exchange optical pumping of 3He for neutron polarizers

International Nuclear Information System (INIS)

Gentile, T.R.; Thompson, A.K.; Snow, W.M.

1995-01-01

Research is underway at NIST and IU to develop neutron polarizers that are based on polarized 3 He. Such polarizers rely on the strong spin dependence of the cross section for neutron capture by polarized 3 He. Two methods can produce the high density of polarized 3 He gas (10 19 -10 20 cm -3 ) required for an effective neutron polarizer: spin-exchange optical pumping, which is performed directly at high pressure (1-10 bar), and metastability-exchange optical pumping, in which the gas is polarized at low pressure (1 mbar) and then compressed. While we are pursuing both methods, progress in the metastable method will be discussed. The features of the metastable method are the high rate at which the gas can be polarized and the inherent separation of the optical pumping and target cells. In a landmark achievement, researchers at the Univ. of Mainz have developed a piston compressor that can fill a 130 cm 3 cell to a pressure of 7 bar of 45% polarized 3 He gas in 2 hours. We plan to develop a compressor and test it at the NIST Cold Neutron Research Facility. We have constructed a metastable-pumping apparatus at NIST and have obtained 76% polarization with a pumping rate of 1.2 x 10 18 atoms/sec in a 0.4 mbar, 270 cm 3 cell

Linking optical and infrared observations with gravitational wave sources through transient variability

International Nuclear Information System (INIS)

Stubbs, C W

2008-01-01

Optical and infrared observations have thus far detected more celestial cataclysms than have been seen in gravity waves (GW). This argues that we should search for gravity wave signatures that correspond to transient variables seen at optical wavelengths, at precisely known positions. There is an unknown time delay between the optical and gravitational transient, but knowing the source location precisely specifies the corresponding time delays across the gravitational antenna network as a function of the GW-to-optical arrival time difference. Optical searches should detect virtually all supernovae that are plausible gravitational radiation sources. The transient optical signature expected from merging compact objects is not as well understood, but there are good reasons to expect detectable transient optical/IR emission from most of these sources as well. The next generation of deep wide-field surveys (for example PanSTARRS and LSST) will be sensitive to subtle optical variability, but we need to fill the 'blind spots' that exist in the galactic plane, and for optically bright transient sources. In particular, a galactic plane variability survey at λ∼ 2 μm seems worthwhile. Science would benefit from closer coordination between the various optical survey projects and the gravity wave community

Mid-infrared picosecond pump-dump-probe and pump-repump-probe experiments to resolve a ground-state intermediate in cyanobacterial phytochrome Cph1.

Science.gov (United States)

van Wilderen, Luuk J G W; Clark, Ian P; Towrie, Michael; van Thor, Jasper J

2009-12-24

Multipulse picosecond mid-infrared spectroscopy has been used to study photochemical reactions of the cyanobacterial phytochrome photoreceptor Cph1. Different photophysical schemes have been discussed in the literature to describe the pathways after photoexcitation, particularly, to identify reaction phases that are linked to photoisomerisation and electronic decay in the 1566-1772 cm(-1) region that probes C=C and C=O stretching modes of the tetrapyrrole chromophore. Here, multipulse spectroscopy is employed, where, compared to conventional visible pump-mid-infrared probe spectroscopy, an additional visible pulse is incorporated that interacts with populations that are evolving on the excited- and ground-state potential energy surfaces. The time delays between the pump and the dump pulse are chosen such that the dump pulse interacts with different phases in the reaction process. The pump and dump pulses are at the same wavelength, 640 nm, and are resonant with the Pr ground state as well as with the excited state and intermediates. Because the dump pulse additionally pumps the remaining, partially recovered, and partially oriented ground-state population, theory is developed for estimating the fraction of excited-state molecules. The calculations take into account the model-dependent ground-state recovery fraction, the angular dependence of the population transfer resulting from the finite bleach that occurs with linearly polarized intense femtosecond optical excitation, and the partially oriented population for the dump field. Distinct differences between the results from the experiments that use a 1 or a 14 ps dump time favor a branching evolution from S1 to an excited state or reconfigured chromophore and to a newly identified ground-state intermediate (GSI). Optical dumping at 1 ps shows the instantaneous induced absorption of a delocalized C=C stretching mode at 1608 cm(-1), where the increased cross section is associated with the electronic ground

Relaxation of quadrupole orientation in an optically pumped alkali vapour

Energy Technology Data Exchange (ETDEWEB)

Bernabeu, E; Tornos, J

1985-04-01

The relaxation of quadrupole orientation (alignment) in an optically pumped alkali vapour is theoretically studied by taking into account the relaxation processes by alkali-buffer gas, alkali-alkali with spin exchange and alkali-cell wall (diffusion process) collisions. The relaxation transients of the quadrupole orientation are obtained by introducing a first-order weak-pumping approximation (intermediate pumping) less restrictive than the usually considered (zeroth order) one.

Kinetic analysis of rare gas metastable production and optically pumped Xe lasers

Science.gov (United States)

Demyanov, A. V.; Kochetov, I. V.; Mikheyev, P. A.; Azyazov, V. N.; Heaven, M. C.

2018-01-01

Optically pumped all-rare-gas lasers use metastable rare gas atoms as the lasing species in mixtures with He or Ar buffer gas. The metastables are generated in a glow discharge, and we report model calculations for the optimal production of Ne*, Ar*, Kr* and Xe*. Discharge efficiency was estimated by solving the Boltzmann equation. Laser efficiency, gain and output power of the CW optically pumped Xe laser were assessed as functions of heavier rare gas content, pressure, optical pump intensity and the optical path length. It was found that, for efficient operation the heavier rare gas content has to be of the order of one percent or less, and the total pressure—in the range 0.3-1.5 atm. Output power and specific discharge power increase approximately linearly with pump intensity over the output range from 300-500 W cm-2. Ternary mixtures Xe:Ar:He were found to be the most promising. Total laser efficiency was found to be nearly the same for pumping the 2p8 or 2p9 state, reaching 61%-70% for a pump intensity of ~720 W cm-2 when the Xe fraction was in the range 0.001 ÷ 0.01 and Ar fraction—0.1 ÷ 0.5. However, when the 2p8 state was pumped, the maximum total efficiency occurred at larger pressures than for pumping of the 2p9 state. The discharge power density required to sustain a sufficient Xe* number density was in the range of tens of watts per cubic centimeter for 50% Ar in the mixture.

Quantum mechanical features of optically pumped CW FIR lasers

Science.gov (United States)

Seligson, D.; Leite, J. R. R.; Sanchez, A.; Feld, M. S.; Ducloy, M.

1977-01-01

Quantum mechanical predictions for the gain of an optically pumped CW FIR laser are presented for cases in which one or both of the pump and FIR transitions are pressure or Doppler broadened. The results are compared to those based on the rate equation model. Some of the quantum mechanical predictions are verified in CH3OH.

Infrared Supercontinuum Generation in Optical Fibres

DEFF Research Database (Denmark)

Dupont, Sune Vestergaard Lund

During my PhD studies I have worked with intense lasers and optical fibres. In our conceptual universe the colour of light (wavelength) does not depend on the material in which it propagates. At high intensities however, nonlinear effects change the behaviour of light and rise of new wavelength...... with laser-like intensity is obtained, which otherwise is impossible without the use of more complicated equipment. Until recently, supercontinuum covering the mid-infrared was not possible due to absorption in the silica glass optical fibres are made of. In our project infrared transparent materials...... such as ZBLAN and chalcogenide have been investigated. Using ZBLAN it has been possible to generated a supercontinuum stretching beyond 4200 nm. Supercontinuum generation requires knowledge about the physical properties of the optical fibre in which the pulse-broadening takes place. Consequently thorough...

Measurement of infrared optical constants with visible photons

Science.gov (United States)

Paterova, Anna; Yang, Hongzhi; An, Chengwu; Kalashnikov, Dmitry; Krivitsky, Leonid

2018-04-01

We demonstrate a new scheme for infrared spectroscopy with visible light sources and detectors. The technique relies on the nonlinear interference of correlated photons, produced via spontaneous parametric down conversion in a nonlinear crystal. Visible and infrared photons are split into two paths and the infrared photons interact with the sample under study. The photons are reflected back to the crystal, resembling a conventional Michelson interferometer. Interference of the visible photons is observed and it is dependent on the phases of all three interacting photons: pump, visible and infrared. The transmission coefficient and the refractive index of the sample in the infrared range can be inferred from the interference pattern of visible photons. The method does not require the use of potentially expensive and inefficient infrared detectors and sources, it can be applied to a broad variety of samples, and it does not require a priori knowledge of sample properties in the visible range.

A far-infrared spectroscopic survey of intermediate redshift (ultra) luminous infrared galaxies

International Nuclear Information System (INIS)

Magdis, Georgios E.; Rigopoulou, D.; Hopwood, R.; Clements, D.; Huang, J.-S.; Farrah, D.; Pearson, C.; Alonso-Herrero, Almudena; Bock, J. J.; Cooray, A.; Griffin, M. J.; Oliver, S.; Perez Fournon, I.; Riechers, D.; Swinyard, B. M.; Thatte, N.; Scott, D.; Valtchanov, I.; Vaccari, M.

2014-01-01

We present Herschel far-IR photometry and spectroscopy as well as ground-based CO observations of an intermediate redshift (0.21 ≤ z ≤ 0.88) sample of Herschel-selected (ultra)-luminous infrared galaxies (L IR > 10 11.5 L ☉ ). With these measurements, we trace the dust continuum, far-IR atomic line emission, in particular [C II] 157.7 μm, as well as the molecular gas of z ∼ 0.3 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) and perform a detailed investigation of the interstellar medium of the population. We find that the majority of Herschel-selected intermediate redshift (U)LIRGs have L C II /L FIR ratios that are a factor of about 10 higher than that of local ULIRGs and comparable to that of local normal and high-z star-forming galaxies. Using our sample to bridge local and high-z [C II] observations, we find that the majority of galaxies at all redshifts and all luminosities follow an L C II –L FIR relation with a slope of unity, from which local ULIRGs and high- z active-galactic-nucleus-dominated sources are clear outliers. We also confirm that the strong anti-correlation between the L C II /L FIR ratio and the far-IR color L 60 /L 100 observed in the local universe holds over a broad range of redshifts and luminosities, in the sense that warmer sources exhibit lower L C II /L FIR at any epoch. Intermediate redshift ULIRGs are also characterized by large molecular gas reservoirs and by lower star formation efficiencies compared to that of local ULIRGs. The high L C II /L FIR ratios, the moderate star formation efficiencies (L IR /L CO ′ or L IR /M H 2 ), and the relatively low dust temperatures of our sample (which are also common characteristics of high-z star-forming galaxies with ULIRG-like luminosities) indicate that the evolution of the physical properties of (U)LIRGs between the present day and z > 1 is already significant by z ∼ 0.3.

Observations of far-infrared line profiles in the Orion-KL region

International Nuclear Information System (INIS)

Crawford, M.K.; Lugten, J.B.; Fitelson, W.; Genzel, R.; Melnick, G.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)

1986-01-01

Measurements of several far-infrared emission line profiles in the Orion-KL region are reported. The emission from the CO, OH, and forbidden O I emission lines toward the BN-KL and H2 peak 1 positions probably comes from dense, hot molecular gas in the Orion-KL shock. The CO and forbidden O I lines have similar profiles, suggesting that the high-velocity forbidden O I emission also arises in magnetohydrodynamic cloud shocks. The velocity centroids of the lines are somewhat blueshifted. The far-infrared data thus support the interpretation that the blue asymmetry of the H2 2 micron lines is not mainly due to differential dust extinction, but rather to the kinematics and geometry of the shocked gas in the Orion-KL outflow. The forbidden O I and CO lines, however, have significantly less extreme blueshifted emission than the H2 lines. Both the forbidden O I 63 micron and forbidden C II 158 micron lines have features strongly supporting a common origin near the surface of the Orion molecular cloud. 28 references

Star formation in the inner galaxy: a far-infrared and radio study of two H2 regions

International Nuclear Information System (INIS)

Lester, D.F.; Dinerstein, H.L.; Werner, M.W.; Harvey, P.M.; Evans, N.J.II; Brown, R.L.

1985-12-01

Far-infrared and radio continuum maps have been made of the central 6' of the inner-galaxy H II regions G30.8-0.0 (in the W43 complex) and G25.4-02., along with radio and molecular line measurements at selected positions. An effort is made to understand far infrared wavelingths allow the dust temperature structures and total far infrared fluxes to be determined. Comparison of the radio and infrared maps shows a close relationship between the ionized gas and the infrared-emitting material. There is evidence that parts of G30.8 are substantially affected by extinction, even at far-infrared wavelengths. For G25.4-0.2, the radio recombination line and CO line data permit resolution of the distance ambiguity for this source. The confusion in distance determination is found to result from an extraordinary near-superposition of two bright H II regions. Using revised distances of 4.3 kpc for G26.4SE and 12 kpc for G25.4NW, that the latter, which is apparently the fainter of the two sources, is actually the more luminous. Though it is not seen on the Palomar Sky Survey, G25.4SE is easily visible in the 9532A line of S III and is mapped in this line. The ratio of total luminosity to ionizing luminosity is very similar to that of H II regions in the solar circle. Assuming a coeval population of ionizing stars, a normal initial mass function is indicated

Star formation in the inner galaxy: a far-infrared and radio study of two H2 regions

International Nuclear Information System (INIS)

Lester, D.F.; Dinerstein, H.L.; Werner, M.W.; Harvey, P.M.; Evans, N.J.; Brown, R.L.

1985-09-01

Far-infrared and radio continuum maps have been made of the central 6' of the inner-galaxy HII regions G30.8-0.0 (in the W43 complex) and G25.4-0.2, along with radio and molecular line measurements at selected positions. The purpose of this study is an effort to understand star formation in the molecular ring at 5 kpc in galactic radius. Measurements at several far infrared wavelengths allow the dust temperature structures and total far infrared fluxes to be determined. Comparison of the radio and infrared maps shows a close relationship between the ionized gas and the infrared-emitting material. There is evidence that parts of G30.8 are substantially affected by extinction, even at far-infrared wavelengths. Using radio recombination line and CO line data for G25.4-0.2, the distance ambiguity for this source is resolved. The large distance previously ascribed to the entire complex is found to apply to only one of the two main components. The confusion in distance determination is found to result from an extraordinary near-superposition of two bright HII regions. Using the revised distances of 4.3 kpc for G25.4SE and 12 kpc for G25.4NW, it is found that the latter, which is apparently the fainter of the two sources, is actually the more luminous. The ratio of total luminosity to ionizing luminosity is very similar to that of HII regions in the solar circle. Assuming a coeval population of ionizing stars, a normal initial mass function is indicated

Optical pumping and negative luminescence polarization in charged GaAs quantum dots

Science.gov (United States)

Shabaev, Andrew; Stinaff, Eric A.; Bracker, Allan S.; Gammon, Daniel; Efros, Alexander L.; Korenev, Vladimir L.; Merkulov, Igor

2009-01-01

Optical pumping of electron spins and negative photoluminescence polarization are observed when interface quantum dots in a GaAs quantum well are excited nonresonantly by circularly polarized light. Both observations can be explained by the formation of long-lived dark excitons through hole spin relaxation in the GaAs quantum well prior to exciton capture. In this model, optical pumping of resident electron spins is caused by capture of dark excitons and recombination in charged quantum dots. Negative polarization results from accumulation of dark excitons in the quantum well and is enhanced by optical pumping. The dark exciton model describes the experimental results very well, including intensity and bias dependence of the photoluminescence polarization and the Hanle effect.

The Far-Infrared Radio Correlation at High-z : Prospects for the SKA

NARCIS (Netherlands)

Murphy, Eric J.

2009-01-01

In this conference proceedings article I summarize the recent work of Murphy (2009) which presents physically motivated predictions for the evolution of the Far-Infrared--radio correlation as a function of redshift arising from variations in the cosmic-ray (CR) electron cooling time-scales as

Rovibrational optical pumping of a molecular beam

Science.gov (United States)

Cournol, A.; Pillet, P.; Lignier, H.; Comparat, D.

2018-03-01

The preparation of molecules in well-defined internal states is essential for various studies in fundamental physics and physical chemistry. It is thus of particular interest to find methods that increase the brightness of molecular beams. Here, we report on rotational and vibrational pumpings of a supersonic beam of barium monofluoride molecules. With respect to previous works, the time scale of optical vibrational pumping has been greatly reduced by enhancing the spectral power density in the vicinity of the appropriate molecular transitions. We demonstrate a complete transfer of the rovibrational populations lying in v″=1 -3 into the vibrational ground-state v″=0 . Rotational pumping, which requires efficient vibrational pumping, has been also demonstrated. According to a Maxwell-Boltzmann description, the rotational temperature of our sample has been reduced by a factor of ˜8 . In this fashion, the population of the lowest rotational levels increased by more than one order of magnitude.

Pump-induced optical distortions in disk amplifier modules: holographic and interferometric measurements

International Nuclear Information System (INIS)

Linford, G.J.; Chau, H.H.; Glaze, J.A.; Layne, C.B.; Rainer, F.

1975-01-01

Interferometric measurements have been made of the optical distortions induced in laser disk amplifiers during the flashlamp pumping pulse. Both conventional interferometric methods and the techniques of double exposure holographic interferometry were used to identify four major sources of pump-induced optical distortions: subsonic intrusion of hot gas (traced to leakage of atmospheric oxygen into the amplifier), microexplosions of dust particles, thermally induced optical distortions in the glass disks, and gaseous optical distortion effects caused by turbulent flow of the purging nitrogen gas supply used within the laser amplifier head. Methods for reducing or eliminating the effects of each of these optical distortions are described

A mid- to far-infrared variability study of the intermediate Seyfert galaxy, Mk 6

International Nuclear Information System (INIS)

Clement, R.; Sembay, S.; Coe, M.J.; Hanson, C.G.

1988-01-01

A mid- to far-infrared (MFIR) variability study of the intermediate Seyfert galaxy, Mk 6, is presented using data from the Infrared Astronomical Satellite (IRAS). We have analysed 25 observations of this source covering a period of about 1 month. Within the expected errors, the source shows no evidence for variability and this may be an indication that there is a strong contribution to the MFIR emission from thermal re-radiation by dust. This interpretation is consistent with previous studies which suggest that the bulk of the far-infrared (30 -100 μm) emission in Seyfert galaxies originates from cool (35 - 75 K) dust associated with star formation regions in the surrounding envelope of the active nucleus. The lack of variability at 12 and 25 μm can also be readily explained by dust emission. However, in this case, the dust temperatures required to produce emission at these wavelengths makes the narrow-line region a more feasible location for the dust grains. (author)

Rate equation modelling of the optically pumped spin-exchange source

International Nuclear Information System (INIS)

Stenger, J.; Rith, K.

1995-01-01

Sources for spin polarized hydrogen or deuterium, polarized via spin-exchange of a laser optically pumped alkali metal, can be modelled by rate equations. The rate equations for this type of source, operated either with hydrogen or deuterium, are given explicitly with the intention of providing a useful tool for further source optimization and understanding. Laser optical pumping of alkali metal, spin-exchange collisions of hydrogen or deuterium atoms with each other and with alkali metal atoms are included, as well as depolarization due to flow and wall collisions. (orig.)

Broadband and tunable optical parametric generator for remote detection of gas molecules in the short and mid-infrared.

Science.gov (United States)

Lambert-Girard, Simon; Allard, Martin; Piché, Michel; Babin, François

2015-04-01

The development of a novel broadband and tunable optical parametric generator (OPG) is presented. The OPG properties are studied numerically and experimentally in order to optimize the generator's use in a broadband spectroscopic LIDAR operating in the short and mid-infrared. This paper discusses trade-offs to be made on the properties of the pump, crystal, and seeding signal in order to optimize the pulse spectral density and divergence while enabling energy scaling. A seed with a large spectral bandwidth is shown to enhance the pulse-to-pulse stability and optimize the pulse spectral density. A numerical model shows excellent agreement with output power measurements; the model predicts that a pump having a large number of longitudinal modes improves conversion efficiency and pulse stability.

Experimental realization of optical lumped nanocircuits at infrared wavelengths.

Science.gov (United States)

Sun, Yong; Edwards, Brian; Alù, Andrea; Engheta, Nader

2012-01-29

The integration of radiofrequency electronic methodologies on micro- as well as nanoscale platforms is crucial for information processing and data-storage technologies. In electronics, radiofrequency signals are controlled and manipulated by 'lumped' circuit elements, such as resistors, inductors and capacitors. In earlier work, we theoretically proposed that optical nanostructures, when properly designed and judiciously arranged, could behave as nanoscale lumped circuit elements--but at optical frequencies. Here, for the first time we experimentally demonstrate a two-dimensional optical nanocircuit at mid-infrared wavelengths. With the guidance of circuit theory, we design and fabricate arrays of Si3N4 nanorods with specific deep subwavelength cross-sections, quantitatively evaluate their equivalent impedance as lumped circuit elements in the mid-infrared regime, and by Fourier transform infrared spectroscopy show that these nanostructures can indeed function as two-dimensional optical lumped circuit elements. We further show that the connections among nanocircuit elements, in particular whether they are in series or in parallel combination, can be controlled by the polarization of impinging optical signals, realizing the notion of 'stereo-circuitry' in metatronics-metamaterials-inspired optical circuitry.

Inverted cones grating for flexible metafilter at optical and infrared frequencies

Energy Technology Data Exchange (ETDEWEB)

Brückner, Jean-Baptiste; Le Rouzo, Judikaël; Escoubas, Ludovic [Aix-Marseille Université, IM2NP, CNRS-UMR 7334, Domaine Universitaire de Saint-Jérôme, Service 231, 13397 Marseille Cedex 20 (France); Brissonneau, Vincent; Dubarry, Christophe [CEA-LITEN DTNM, 17 Avenue des Martyrs, 38054 Grenoble cedex 9 (France); Ferchichi, Abdelkerim; Gourgon, Cécile [LTM CNRS, Laboratoire des Technologies de la Microélectronique 17 Avenue des Martyrs, 38054 Grenoble cedex 9 (France); Berginc, Gérard [Thales Optronique S.A., 2 Avenue Gay Lussac, 78990 Elancourt (France)

2014-02-24

By combining the antireflective properties from gradual changes in the effective refractive index and cavity coupling from cone gratings and the efficient optical behavior of a tungsten film, a flexible filter showing very broad antireflective properties from the visible to short wavelength infrared region and, simultaneously, a mirror-like behavior in the mid-infrared wavelength region and long-infrared wavelength region has been conceived. Nanoimprint technology has permitted the replication of inverted cone patterns on a large scale on a flexible polymer, afterwards coated with a thin tungsten film. This optical metafilter is of great interest in the stealth domain where optical signature reduction from the optical to short wavelength infrared region is an important matter. As it also acts as selective thermal emitter offering a good solar-absorption/infrared-emissivity ratio, interests are found as well for solar heating applications.

Effect of multiple circular holes Fraunhofer diffraction for the infrared optical imaging

Science.gov (United States)

Lu, Chunlian; Lv, He; Cao, Yang; Cai, Zhisong; Tan, Xiaojun

2014-11-01

With the development of infrared optics, infrared optical imaging systems play an increasingly important role in modern optical imaging systems. Infrared optical imaging is used in industry, agriculture, medical, military and transportation. But in terms of infrared optical imaging systems which are exposed for a long time, some contaminations will affect the infrared optical imaging. When the contamination contaminate on the lens surface of the optical system, it would affect diffraction. The lens can be seen as complementary multiple circular holes screen happen Fraunhofer diffraction. According to Babinet principle, you can get the diffraction of the imaging system. Therefore, by studying the multiple circular holes Fraunhofer diffraction, conclusions can be drawn about the effect of infrared imaging. This paper mainly studies the effect of multiple circular holes Fraunhofer diffraction for the optical imaging. Firstly, we introduce the theory of Fraunhofer diffraction and Point Spread Function. Point Spread Function is a basic tool to evaluate the image quality of the optical system. Fraunhofer diffraction will affect Point Spread Function. Then, the results of multiple circular holes Fraunhofer diffraction are given for different hole size and hole spacing. We choose the hole size from 0.1mm to 1mm and hole spacing from 0.3mm to 0.8mm. The infrared wavebands of optical imaging are chosen from 1μm to 5μm. We use the MATLAB to simulate light intensity distribution of multiple circular holes Fraunhofer diffraction. Finally, three-dimensional diffraction maps of light intensity are given to contrast.

Optical/Infrared Signatures for Space-Based Remote Sensing

National Research Council Canada - National Science Library

Picard, R. H; Dewan, E. M; Winick, J. R; O'Neil, R. R

2007-01-01

This report describes work carried out under the Air Force Research Laboratory's basic research task in optical remote-sensing signatures, entitled Optical / Infrared Signatures for Space-Based Remote Sensing...

Efficient Ho:YLF laser pumped by a Tm:fiber laser

CSIR Research Space (South Africa)

Koen, W

2013-07-01

Full Text Available Laser sources emitting in the 2 micron region is of particular interest for applications in medicine, remote sensing (LIDAR) and directed infra-red countermeasures. In addition, they are also desirable pump sources for efficient optical parametric...

Far-Infrared and Millimeter Continuum Studies of K-Giants: Alpha Boo and Alpha Tau

Science.gov (United States)

Cohen, Martin; Carbon, Duane F.; Welch, William J.; Lim, Tanya; Forster, James R.; Goorvitch, David; Thigpen, William (Technical Monitor)

2002-01-01

We have imaged two normal, non-coronal, infrared-bright K-giants, alpha Boo and alpha Tau, in the 1.4-millimeter and 2.8-millimeter continuum using BIMA. These stars have been used as important absolute calibrators for several infrared satellites. Our goals are: (1) to probe the structure of their upper photospheres; (2) to establish whether these stars radiate as simple photospheres or possess long-wavelength chromospheres; and (3) to make a connection between millimeter-wave and far-infrared absolute flux calibrations. To accomplish these goals we also present ISO Long Wavelength Spectrometer (LWS) measurements of both these K-giants. The far-infrared and millimeter continuum radiation is produced in the vicinity of the temperature minimum in a Boo and a Tau, offering a direct test of the model photospheres and chromospheres for these two cool giants. We find that current photospheric models predict fluxes in reasonable agreement with those observed for those wavelengths which sample the upper photosphere, namely less than or equal to 170 micrometers in alpha Tau and less than or equal to 125 micrometers in alpha Boo. It is possible that alpha Tau is still radiative as far as 0.9 - 1.4 millimeters. We detect chromospheric radiation from both stars by 2.8 millimeters (by 1.4 millimeters in alpha Boo), and are able to establish useful bounds on the location of the temperature minimum. An attempt to interpret the chromospheric fluxes using the two-component "bifurcation model" proposed by Wiedemann et al. (1994) appears to lead to a significant contradiction.

Optical Pumping of the Electronic and Nuclear Spin of Single Charge-Tunable Quantum Dots

Science.gov (United States)

Bracker, A. S.; Stinaff, E. A.; Gammon, D.; Ware, M. E.; Tischler, J. G.; Shabaev, A.; Efros, Al. L.; Park, D.; Gershoni, D.; Korenev, V. L.; Merkulov, I. A.

2005-02-01

We present a comprehensive examination of optical pumping of spins in individual GaAs quantum dots as we change the net charge from positive to neutral to negative with a charge-tunable heterostructure. Negative photoluminescence polarization memory is enhanced by optical pumping of ground state electron spins, which we prove with the first measurements of the Hanle effect on an individual quantum dot. We use the Overhauser effect in a high longitudinal magnetic field to demonstrate efficient optical pumping of nuclear spins for all three charge states of the quantum dot.

FAR-INFRARED PROPERTIES OF SPITZER-SELECTED LUMINOUS STARBURSTS

International Nuclear Information System (INIS)

Kovacs, A.; Omont, A.; Fiolet, N.; Beelen, A.; Dole, H.; Lagache, G.; Lonsdale, C.; Polletta, M.; Greve, T. R.; Borys, C.; Dowell, C. D.; Bell, T. A.; Cox, P.; De Breuck, C.; Farrah, D.; Menten, K. M.; Owen, F.

2010-01-01

We present SHARC-2 350 μm data on 20 luminous z ∼ 2 starbursts with S 1.2 m m > 2 mJy from the Spitzer-selected samples of Lonsdale et al. and Fiolet et al. All the sources were detected, with S 350 μ m > 25 mJy for 18 of them. With the data, we determine precise dust temperatures and luminosities for these galaxies using both single-temperature fits and models with power-law mass-temperature distributions. We derive appropriate formulae to use when optical depths are non-negligible. Our models provide an excellent fit to the 6 μm-2 mm measurements of local starbursts. We find characteristic single-component temperatures T 1 ≅ 35.5 ± 2.2 K and integrated infrared (IR) luminosities around 10 12.9±0.1 L sun for the SWIRE-selected sources. Molecular gas masses are estimated at ≅4 x 10 10 M sun , assuming κ 850 μ m = 0.15 m 2 kg -1 and a submillimeter-selected galaxy (SMG)-like gas-to-dust mass ratio. The best-fit models imply ∼>2 kpc emission scales. We also note a tight correlation between rest-frame 1.4 GHz radio and IR luminosities confirming star formation as the predominant power source. The far-IR properties of our sample are indistinguishable from the purely submillimeter-selected populations from current surveys. We therefore conclude that our original selection criteria, based on mid-IR colors and 24 μm flux densities, provides an effective means for the study of SMGs at z ∼ 1.5-2.5.

Infrared emission from protostars

International Nuclear Information System (INIS)

Adams, F.C.; Shu, F.H.

1985-01-01

The emergent spectral energy distribution at infrared to radio wavelengths is calculated for the simplest theoretical construct of a low-mass protostar. It is shown that the emergent spectrum in the infrared is insensitive to the details assumed for the temperature profile as long as allowance is made for a transition from optically thick to optically thin conditions and luminosity conservation isenforced at the inner and outer shells. The radiation in the far infrared and submillimeter wavelengths depends on the exact assumptions made for grain opacities at low frequencies. An atlas of emergent spectral energy distributions is presented for a grid of values of the instantaneous mass of the protostar and the mass infall rate. The attenuated contribution of the accretion shock to the near-infrared radiation is considered. 50 references

HerMES: THE FAR-INFRARED EMISSION FROM DUST-OBSCURED GALAXIES

International Nuclear Information System (INIS)

Calanog, J. A.; Wardlow, J.; Fu, Hai; Cooray, A.; Assef, R. J.; Bock, J.; Riechers, D.; Schulz, B.; Casey, C. M.; Conley, A.; Farrah, D.; Oliver, S. J.; Roseboom, I. G.; Ibar, E.; Kartaltepe, J.; Magdis, G.; Rigopoulou, D.; Marchetti, L.; Pérez-Fournon, I.; Scott, Douglas

2013-01-01

Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ∼ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg 2 of the Cosmic Evolution Survey. The 3077 DOGs have (z) = 1.9 ± 0.3 and are selected from 24 μm and r + observations using a color cut of r + – [24] ≥ 7.5 (AB mag) and S 24 ≥ 100 μJy. Based on the near-IR spectral energy distributions, 47% are bump DOGs (star formation dominated) and 10% are power-law DOGs (AGN-dominated). We use SPIRE far-IR photometry from the Herschel Multi-tiered Extragalactic Survey to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250 μm (≥3σ). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Herschel-detected and undetected DOGs have average luminosities of (2.8 ± 0.4) × 10 12 L ☉ and (0.77 ± 0.08) × 10 12 L ☉ , and dust temperatures of (33 ± 7) K and (37 ± 5) K, respectively. The IR luminosity function for DOGs with S 24 ≥ 100 μJy is calculated, using far-IR observations and stacking. DOGs contribute 10%-30% to the total star formation rate (SFR) density of the universe at z = 1.5-2.5, dominated by 250 μm detected and bump DOGs. For comparison, DOGs contribute 30% to the SFR density for all z = 1.5-2.5 galaxies with S 24 ≥ 100 μJy. DOGs have a large scatter about the star formation main sequence and their specific SFRs show that the observed phase of star formation could be responsible for their total observed stellar mass at z ∼ 2

HerMES: THE FAR-INFRARED EMISSION FROM DUST-OBSCURED GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Calanog, J. A.; Wardlow, J.; Fu, Hai; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Assef, R. J. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Bock, J.; Riechers, D.; Schulz, B. [California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Casey, C. M. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Farrah, D.; Oliver, S. J.; Roseboom, I. G. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Ibar, E. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Kartaltepe, J. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Magdis, G.; Rigopoulou, D. [Department of Astrophysics, Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Marchetti, L. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Pérez-Fournon, I. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Scott, Douglas [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); and others

2013-09-20

Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ∼ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg{sup 2} of the Cosmic Evolution Survey. The 3077 DOGs have (z) = 1.9 ± 0.3 and are selected from 24 μm and r {sup +} observations using a color cut of r {sup +} – [24] ≥ 7.5 (AB mag) and S{sub 24} ≥ 100 μJy. Based on the near-IR spectral energy distributions, 47% are bump DOGs (star formation dominated) and 10% are power-law DOGs (AGN-dominated). We use SPIRE far-IR photometry from the Herschel Multi-tiered Extragalactic Survey to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250 μm (≥3σ). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Herschel-detected and undetected DOGs have average luminosities of (2.8 ± 0.4) × 10{sup 12} L{sub ☉} and (0.77 ± 0.08) × 10{sup 12} L{sub ☉}, and dust temperatures of (33 ± 7) K and (37 ± 5) K, respectively. The IR luminosity function for DOGs with S{sub 24} ≥ 100 μJy is calculated, using far-IR observations and stacking. DOGs contribute 10%-30% to the total star formation rate (SFR) density of the universe at z = 1.5-2.5, dominated by 250 μm detected and bump DOGs. For comparison, DOGs contribute 30% to the SFR density for all z = 1.5-2.5 galaxies with S{sub 24} ≥ 100 μJy. DOGs have a large scatter about the star formation main sequence and their specific SFRs show that the observed phase of star formation could be responsible for their total observed stellar mass at z ∼ 2.

Holography and thermalization in optical pump-probe spectroscopy

Science.gov (United States)

Bagrov, A.; Craps, B.; Galli, F.; Keränen, V.; Keski-Vakkuri, E.; Zaanen, J.

2018-04-01

Using holography, we model experiments in which a 2 +1 D strange metal is pumped by a laser pulse into a highly excited state, after which the time evolution of the optical conductivity is probed. We consider a finite-density state with mildly broken translation invariance and excite it by oscillating electric field pulses. At zero density, the optical conductivity would assume its thermalized value immediately after the pumping has ended. At finite density, pulses with significant dc components give rise to slow exponential relaxation, governed by a vector quasinormal mode. In contrast, for high-frequency pulses the amplitude of the quasinormal mode is strongly suppressed, so that the optical conductivity assumes its thermalized value effectively instantaneously. This surprising prediction may provide a stimulus for taking up the challenge to realize these experiments in the laboratory. Such experiments would test a crucial open question faced by applied holography: are its predictions artifacts of the large N limit or do they enjoy sufficient UV independence to hold at least qualitatively in real-world systems?

Spiral intensity patterns in the internally pumped optical parametric oscillator

DEFF Research Database (Denmark)

Lodahl, Peter; Bache, Morten; Saffman, Mark

2001-01-01

We describe a nonlinear optical system that supports spiral pattern solutions in the field intensity. This new spatial structure is found to bifurcate above a secondary instability in the internally pumped optical parametric oscillator. The analytical predictions of threshold and spatial scale...

Frequency comb generation in a continuously pumped optical parametric oscillator

Science.gov (United States)

Mosca, S.; Parisi, M.; Ricciardi, I.; Leo, F.; Hansson, T.; Erkintalo, M.; Maddaloni, P.; De Natale, P.; Wabnitz, S.; De Rosa, M.

2018-02-01

We demonstrate optical frequency comb generation in a continuously pumped optical parametric oscillator, in the parametric region around half of the pump frequency. We also model the dynamics of such quadratic combs using a single time-domain mean-field equation, and obtain simulation results that are in good agreement with experimentally observed spectra. Moreover, we numerically investigate the coherence properties of simulated combs, showing the existence of correlated and phase-locked combs. Our work could pave the way for a new class of frequency comb sources, which may enable straightforward access to new spectral regions and stimulate novel applications of frequency combs.

The Large UV/Optical/Infrared Surveyor (LUVOIR): Decadal Mission concept design update

Science.gov (United States)

Bolcar, Matthew R.; Aloezos, Steve; Bly, Vincent T.; Collins, Christine; Crooke, Julie; Dressing, Courtney D.; Fantano, Lou; Feinberg, Lee D.; France, Kevin; Gochar, Gene; Gong, Qian; Hylan, Jason E.; Jones, Andrew; Linares, Irving; Postman, Marc; Pueyo, Laurent; Roberge, Aki; Sacks, Lia; Tompkins, Steven; West, Garrett

2017-09-01

In preparation for the 2020 Astrophysics Decadal Survey, NASA has commissioned the study of four large mission concepts, including the Large Ultraviolet / Optical / Infrared (LUVOIR) Surveyor. The LUVOIR Science and Technology Definition Team (STDT) has identified a broad range of science objectives including the direct imaging and spectral characterization of habitable exoplanets around sun-like stars, the study of galaxy formation and evolution, the epoch of reionization, star and planet formation, and the remote sensing of Solar System bodies. NASA's Goddard Space Flight Center (GSFC) is providing the design and engineering support to develop executable and feasible mission concepts that are capable of the identified science objectives. We present an update on the first of two architectures being studied: a 15- meter-diameter segmented-aperture telescope with a suite of serviceable instruments operating over a range of wavelengths between 100 nm to 2.5 μm. Four instruments are being developed for this architecture: an optical / near-infrared coronagraph capable of 10-10 contrast at inner working angles as small as 2 λ/D the LUVOIR UV Multi-object Spectrograph (LUMOS), which will provide low- and medium-resolution UV (100 - 400 nm) multi-object imaging spectroscopy in addition to far-UV imaging; the High Definition Imager (HDI), a high-resolution wide-field-of-view NUV-Optical-IR imager; and a UV spectro-polarimeter being contributed by Centre National d'Etudes Spatiales (CNES). A fifth instrument, a multi-resolution optical-NIR spectrograph, is planned as part of a second architecture to be studied in late 2017.

Dynamic characterization of silicon nanowires using a terahertz optical asymmetric demultiplexer-based pump-probe scheme

DEFF Research Database (Denmark)

Ji, Hua; Cleary, C. S.; Dailey, J. M.

2012-01-01

Dynamic phase and amplitude all-optical responses of silicon nanowires are characterized using a terahertz optical asymmetric demultiplexer (TOAD) based pump-probe scheme. Ultra-fast recovery is observed for moderate pump powers....

A study of far-infrared Michelson interferometry based on fast plasma scanning

International Nuclear Information System (INIS)

Bartlett, D.V.; Hewitt, G.L.; Robinson, L.C.; Tait, G.D.

1976-02-01

Fast far-infrared multiplex spectroscopy based on a plasma-scanned Michelson interferometer is studied. Our experiments show that the interferometer has sub-millisecond time response and high spectral resolving power. In addition to a description of the experimental performance of the interferometer, we develop and discuss two different methods of interferogram inversion. (author)

A study of far-infrared Michelson interferometry based on fast plasma scanning

International Nuclear Information System (INIS)

Bartlett, D.V.; Hewitt, R.G.L.; Robinson, L.C.; Tait, G.D.

1977-01-01

Fast far infrared (FIR) muliplex spectroscopy based on a plasma-scanned Michelson interferometer is studied. Experiments show that the interferometer has sub-millisecond time response and high spectral resolving power. In addition to the description of the experimental performance of the interferometer, two different methods of interferogram inversion are developed and discussed. (author)

THE EXTRAORDINARY FAR-INFRARED VARIATION OF A PROTOSTAR: HERSCHEL/PACS OBSERVATIONS OF LRLL54361

Energy Technology Data Exchange (ETDEWEB)

Balog, Zoltan; Detre, Örs H.; Bouwmann, Jeroen; Nielbock, Markus; Klaas, Ulrich; Krause, Oliver; Henning, Thomas [Max Planck Institute for Astronomy Königstuhl 17, Heidelberg D-69117 (Germany); Muzerolle, James [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Flaherty, Kevin [Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States); Furlan, Elise [Natinal Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Gutermuth, Rob [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Juhasz, Attila [Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333-CA Leiden (Netherlands); Bally, John [CASA, University of Colorado, CB 389, Boulder, CO 80309 (United States); Marton, Gabor, E-mail: balog@mpia.de [Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege 15-17, 1121 Budapest (Hungary)

2014-07-10

We report Herschel/Photodetector Array Camera and Spectrometer (PACS) photometric observations at 70 μm and 160 μm of LRLL54361—a suspected binary protostar that exhibits periodic (P = 25.34 days) flux variations at shorter wavelengths (3.6 μm and 4.5 μm) thought to be due to pulsed accretion caused by binary motion. The PACS observations show unprecedented flux variation at these far-infrared wavelengths that are well correlated with the variations at shorter wavelengths. At 70 μm the object increases its flux by a factor of six while at 160 μm the change is about a factor of two, consistent with the wavelength dependence seen in the far-infrared spectra. The source is marginally resolved at 70 μm with varying FWHM. Deconvolved images of the sources show elongations exactly matching the outflow cavities traced by the scattered light observations. The spatial variations are anti-correlated with the flux variation, indicating that a light echo is responsible for the changes in FWHM. The observed far-infrared flux variability indicates that the disk and envelope of this source is periodically heated by the accretion pulses of the central source, and suggests that such long wavelength variability in general may provide a reasonable proxy for accretion variations in protostars.

A High-Power Continuous-Wave Mid-Infrared Optical Parametric Oscillator Module

Directory of Open Access Journals (Sweden)

Yichen Liu

2017-12-01

Full Text Available We demonstrate here a compact optical parametric oscillator module for mid-infrared generation via nonlinear frequency conversion. This module weighs only 2.5 kg and fits within a small volume of 220 × 60 × 55 mm3. The module can be easily aligned to various pump laser sources, and here we use a 50 W ytterbium (Yb-doped fiber laser as an example. With a two-channel MgO-doped periodically poled lithium niobate crystal (MgO:PPLN, our module covers a tuning range of 2416.17–2932.25 nm and 3142.18–3452.15 nm. The highest output power exceeds 10.4 W at 2.7 μm, corresponding to a conversion efficiency of 24%. The measured power stability is 2.13% Root Meat Square (RMS for a 10 h duration under outdoor conditions.

Direct pumping of ultrashort Ti:sapphire lasers by a frequency doubled diode laser

DEFF Research Database (Denmark)

Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

2011-01-01

electro-optical efficiency of the diode laser. Autocorrelation measurements show that pulse widths of less than 20 fs can be expected with an average power of 52 mW when using our laser. These results indicate the high potential of direct diode laser pumped Ti: sapphire lasers to be used in applications....... When using our diode laser system, the optical conversion efficiencies from green to near-infrared light reduces to 75 % of the values achieved with the commercial pump laser. Despite this reduction the overall efficiency of the Ti: sapphire laser is still increased by a factor > 2 due to the superior...... like retinal optical coherence tomography (OCT) or pumping of photonic crystal fibers for CARS (coherent anti-stokes Raman spectroscopy) microscopy....

Properties in the middle and far infrared radiation of spiral and irregular galaxies

International Nuclear Information System (INIS)

Contursi, Alessandra

1998-01-01

In the first part of this research thesis, the author reports the study in the middle infrared of H II regions belonging to Magellanic clouds. For this purpose, he presents different aspects of infrared emission by the interstellar medium: origin and evolution of interstellar grains, dust studied by astrophysical observations, dust models, infrared observations made by COBE and IRAS satellites, exploitation of the ISO satellite. He also presents the Small and Large Magellanic clouds, and reports the study of the H II N4 region of the large one, imagery and spectroscopy of the H II N66 region of the small one, and the study of silicate emission in the central region of N66. The second part reports the study of cluster normal spiral galaxies in the middle and far infrared. For this purpose, the author discusses the colours in the middle infrared of Virgo's and Coma's galaxies, discusses the properties in the infrared of spiral galaxies (Coma and A1367), based on observations made by ISO [fr

Comparative investigation of long-wave infrared generation based on ZnGeP{sub 2} and CdSe optical parametric oscillators

Energy Technology Data Exchange (ETDEWEB)

Bao-Quan, Yao; Gang, Li; Guo-Li, Zhu; Pei-Bei, Meng; You-Lun, Ju; Wang Yue-Zhu, E-mail: yaobq08@hit.edu.cn [National Key Laboratory of Tunable Laser Technology Harbin Institute of Technology Harbin 150001 (China)

2012-03-15

Long-wave infrared (IR) generation based on type-II (o{yields}e+o) phase matching ZnGeP{sub 2} (ZGP) and CdSe optical parametric oscillators (OPOs) pumped by a 2.05 {mu}m Tm,Ho:GdVO{sub 4} laser is reported. The comparisons of the bire-fringent walk-off effect and the oscillation threshold between ZGP and CdSe OPOs are performed theoretically and experimentally. For the ZGP OPO, up to 419 mW output at 8.04 {mu}m is obtained at the 8 kHz pump pulse repetition frequency (PRF) with a slope efficiency of 7.6%. This ZGP OPO can be continuously tuned from 7.8 to 8.5 {mu}m. For the CdSe OPO, we demonstrate a 64 mW output at 8.9 {mu}m with a single crystal 28 mm in length. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

THE FAR-INFRARED EMISSION FROM THE Mg+-PAH SPECIES

International Nuclear Information System (INIS)

Bauschlicher, Charles W. Jr.; Ricca, Alessandra

2009-01-01

The far-infrared (FIR) spectra of several Mg + -PAH species are studied using density functional theory. The Mg + -PAH stretching mode, regardless of the polycyclic aromatic hydrocarbon (PAH) species, carries a reasonable intensity and tends to fall in a narrow range near 40 μm. Because the bands tend to fall at very similar frequencies, the average spectra of several Mg + -PAH species produce a broadband with an intensity that is about 20% of the well known C-H out-of-plane bending mode. In contrast, an average of seven large compact pure PAHs has no FIR bands that carry any significant intensity.

Effects of optical pumping in the photo-excitation of organic triplet states

International Nuclear Information System (INIS)

Lin, Tien-Sung; Yang, Tran-Chin; Sloop, David J.

2013-01-01

Highlights: • High electron spin polarization (ESP) was observed in pentacene triplets at room temperature. • The high ESP is transfer to the surrounding nuclear spin by optical pumping in zero-field (ZF). • The ZF transition frequencies and their line width depend on the laser pumping rate. • The spin–lattice relaxation times of the nuclear system are evaluated. - Abstract: Upon the application of laser and microwave pulses, non-zero magnetic moment of a photo-excited triplet state of organic molecules is generated in zero-field (ZF). The time evolution of the transient magnetic moments can be measured by free induction decay (FID) in ZF. The observed ZF spectra become broadened and ZF transition shifted to lower frequencies when the repetition rate of laser excitation is increased, which are attributed to the optical pumping of nuclear polarization (ONP) effect and the associated nuclear spin lattice relaxation processes. The observed ONP effect is discussed in terms of the local field effect and spin diffusion processes in optical pumping

Effects of optical pumping in the photo-excitation of organic triplet states

Energy Technology Data Exchange (ETDEWEB)

Lin, Tien-Sung, E-mail: lin@wustl.edu; Yang, Tran-Chin; Sloop, David J.

2013-08-30

Highlights: • High electron spin polarization (ESP) was observed in pentacene triplets at room temperature. • The high ESP is transfer to the surrounding nuclear spin by optical pumping in zero-field (ZF). • The ZF transition frequencies and their line width depend on the laser pumping rate. • The spin–lattice relaxation times of the nuclear system are evaluated. - Abstract: Upon the application of laser and microwave pulses, non-zero magnetic moment of a photo-excited triplet state of organic molecules is generated in zero-field (ZF). The time evolution of the transient magnetic moments can be measured by free induction decay (FID) in ZF. The observed ZF spectra become broadened and ZF transition shifted to lower frequencies when the repetition rate of laser excitation is increased, which are attributed to the optical pumping of nuclear polarization (ONP) effect and the associated nuclear spin lattice relaxation processes. The observed ONP effect is discussed in terms of the local field effect and spin diffusion processes in optical pumping.

Athermalization of infrared dual field optical system based on wavefront coding

Science.gov (United States)

Jiang, Kai; Jiang, Bo; Liu, Kai; Yan, Peipei; Duan, Jing; Shan, Qiu-sha

2017-02-01

Wavefront coding is a technology which combination of the optical design and digital image processing. By inserting a phase mask closed to the pupil plane of the optical system the wavefront of the system is re-modulated. And the depth of focus is extended consequently. In reality the idea is same as the athermalization theory of infrared optical system. In this paper, an uncooled infrared dual field optical system with effective focal as 38mm/19mm, F number as 1.2 of both focal length, operating wavelength varying from 8μm to 12μm was designed. A cubic phase mask was used at the pupil plane to re-modulate the wavefront. Then the performance of the infrared system was simulated with CODEV as the environment temperature varying from -40° to 60°. MTF curve of the optical system with phase mask are compared with the outcome before using phase mask. The result show that wavefront coding technology can make the system not sensitive to thermal defocus, and then realize the athermal design of the infrared optical system.

Origins Space Telescope: The Far Infrared Imager and Polarimeter FIP

Science.gov (United States)

Staguhn, Johannes G.; Chuss, David; Howard, Joseph; Meixner, Margaret; Vieira, Joaquin; Amatucci, Edward; Bradley, Damon; Carter, Ruth; Cooray, Asantha; Flores, Anel; Leisawitz, David; Moseley, Samuel Harvey; Wollack, Edward; Origins Space Telescope Study Team

2018-01-01

The Origins Space Telescope (OST)* is the mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies of NASA Headquarters for the 2020 Astronomy and Astrophysics Decadal survey. The current "concept 1", which envisions a cold (4K) 9m space telescope, includes 5 instruments, providing a wavelength coverage ranging from 6um and 667um. The achievable sensitivity of the observatory will provide three to four orders of magnitude of improvement in sensitivity over current observational capabilities, allowing to address a wide range of new and so far inaccessible scientific questions, ranging from bio-signatures on exo-planets to mapping primordial H_2 from the "dark ages" before the universe went through the phase of re-ionization.Here we present the Far Infrared Imager and Polarimeter (FIP) for OST. The cameral will cover four bands, 40um, 80um, 120um, and 240um. It will allow for differential polarimetry in those bands with the ability to observe two colors in polarimtery mode simultaneously, while all four bands can be observed simultaneously in total power mode. While the confusion limit will be reached in only 32ms at 240um, at 40um the source density on the sky is so low, that at the angular resolution of 1" of OST at this wavelength there will be no source confusion, even for the longest integration times. Science topics that can be addressed by FIP include but are not limited to galactic and extragalactic magnetic field studies, Deep Galaxy Surveys, and Outer Solar System objects..*Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. We welcome you to contact the Science and Technology Definition Team (STDT) with your science needs and ideas by emailing us at ost_info@lists.ipac.caltech.edu

The Andromeda Optical and Infrared Disk Survey

Science.gov (United States)

Sick, J.; Courteau, S.; Cuillandre, J.-C.

2014-03-01

The Andromeda Optical and Infrared Disk Survey has mapped M31 in u* g' r' i' JKs wavelengths out to R = 40 kpc using the MegaCam and WIRCam wide-field cameras on the Canada-France-Hawaii Telescope. Our survey is uniquely designed to simultaneously resolve stars while also carefully reproducing the surface brightness of M31, allowing us to study M31's global structure in the context of both resolved stellar populations and spectral energy distributions. We use the Elixir-LSB method to calibrate the optical u* g' r' i' images by building real-time maps of the sky background with sky-target nodding. These maps are stable to μg ≲ 28.5 mag arcsec-2 and reveal warps in the outer M31 disk in surface brightness. The equivalent WIRCam mapping in the near-infrared uses a combination of sky-target nodding and image-to-image sky offset optimization to produce stable surface brightnesses. This study enables a detailed analysis of the systematics of spectral energy distribution fitting with near-infrared bands where asymptotic giant branch stars impose a significant, but ill-constrained, contribution to the near-infrared light of a galaxy. Here we present panchromatic surface brightness maps and initial results from our near-infrared resolved stellar catalog.

Optical pumping of electron and nuclear spin in a negatively-charged quantum dot

Science.gov (United States)

Bracker, Allan; Gershoni, David; Korenev, Vladimir

2005-03-01

We report optical pumping of electron and nuclear spins in an individual negatively-charged quantum dot. With a bias-controlled heterostructure, we inject one electron into the quantum dot. Intense laser excitation produces negative photoluminescence polarization, which is easily erased by the Hanle effect, demonstrating optical pumping of a long-lived resident electron. The electron spin lifetime is consistent with the influence of nuclear spin fluctuations. Measuring the Overhauser effect in high magnetic fields, we observe a high degree of nuclear spin polarization, which is closely correlated to electron spin pumping.

Observations of far-infrared molecular emission lines from the Orion molecular cloud

International Nuclear Information System (INIS)

Viscuso, P.J.

1986-01-01

The Orion Nebula has been the subject of intensive study for over one hundred years. Far-infrared (FIR) molecular line observations of CO in the shock region surrounding the infrared source IRc2 have suggested that the molecular hydrogen density in the shocked and post-shock gas is roughly 3 x 10 6 cm -3 . The temperature of this gas is on the order of 750-2000K. IRc2, like other nearby infrared sources within the Nebula, is thought to be a site of recent star formation. This object is apparently at the center of a massive bipolar molecular outflow of gas, which is producing a shock front where it meets the ambient molecular cloud surrounding IRc2. Study of such regions is important for the understanding of the chemical and physical processes that are involved in the formation of stars from molecular clouds. Recently, several far-infrared transitions among the low-lying levels of OH have been observed toward IRc2. OH is thought to be abundant, and it plays an important role in the chemical evolution of the shock and post-shock regions. The OH emission serves as a sensitive probe of the temperature and density for the shock-processed gas. A rigorous treatment of the radiative transfer of these measured transitions is performed using the escape probability formalism. From this analysis, the author determines the temperature of the OH-emitting region to be on the order of 40K. This suggests that the gas is part of the post-shock gas that has cooled sufficiently, most likely by way of radiative cooling by CO

Optical analysis and alignment applications using the infrared Smartt interferometer

International Nuclear Information System (INIS)

Viswanathan, V.K.; Bolen, P.D.; Liberman, I.; Seery, B.D.

1981-01-01

The possibility of using the infrared Smartt interferometer for optical analysis and alignment of infrared laser systems has been discussed previously. In this paper, optical analysis of the Gigawatt Test Facility at Los Alamos, as well as a deformable mirror manufactured by Rocketdyne, are discussed as examples of the technique. The possibility of optically characterizing, as well as aligning, pulsed high energy laser systems like Helios and Antares is discussed in some detail

Active Control of Nitride Plasmonic Dispersion in the Far Infrared.

Energy Technology Data Exchange (ETDEWEB)

Shaner, Eric A.; Dyer, Gregory Conrad; Seng, William Francis; Bethke, Donald Thomas; Grine, Albert Dario,; Baca, Albert G.; Allerman, Andrew A.

2014-11-01

We investigate plasmonic structures in nitride-based materials for far-infrared (IR) applications. The two dimensional electron gas (2DEG) in the GaN/AlGaN material system, much like metal- dielectric structures, is a patternable plasmonic medium. However, it also permits for direct tunability via an applied voltage. While there have been proof-of-principle demonstrations of plasma excitations in nitride 2DEGs, exploration of the potential of this material system has thus far been limited. We recently demonstrated coherent phenomena such as the formation of plasmonic crystals, strong coupling of tunable crystal defects to a plasmonic crystal, and electromagnetically induced transparency in GaAs/AlGaAs 2DEGs at sub-THz frequencies. In this project, we explore whether these effects can be realized in nitride 2DEG materials above 1 THz and at temperatures exceeding 77 K.

Dust properties around evolved stars from far-infrared size limits

International Nuclear Information System (INIS)

Harvey, P.M.; Lester, D.F.; Brock, D.; Joy, M.

1991-01-01

High angular resolution far-infrared scans were obtained of six stars surrounded by circumstellar dust shells believed to result from mass loss by the central star. None of the dust shells was clearly resolved at either 50 or 100 microns; the upper limits are in the range 4 to 10 arcsec. These size limits place constraints on the far-IR dust emissivity and dust density distribution. For one of the objects, AFGL 2343, larger than normal grains are almost certainly required. For several other stars, the size limits are much more consistent with dust having an emissivity law no steeper than 1/lambda in the 1-100-micron spectral region. For IRC + 10216, an earlier suggestion is confirmed that, assuming reasonable grain properties, a smooth radial dust distribution is not consistent with the scans and the energy distribution of the object. 29 refs

Measuring gas temperature during spin-exchange optical pumping process

Science.gov (United States)

Normand, E.; Jiang, C. Y.; Brown, D. R.; Robertson, L.; Crow, L.; Tong, X.

2016-04-01

The gas temperature inside a Spin-Exchange Optical Pumping (SEOP) laser-pumping polarized 3He cell has long been a mystery. Different experimental methods were employed to measure this temperature but all were based on either modelling or indirect measurement. To date there has not been any direct experimental measurement of this quantity. Here we present the first direct measurement using neutron transmission to accurately determine the number density of 3He, the temperature is obtained using the ideal gas law. Our result showed a surprisingly high gas temperature of 380°C, compared to the 245°C of the 3He cell wall temperature and 178°C of the optical pumping oven temperature. This experiment result may be used to further investigate the unsolved puzzle of the "X-factor" in the SEOP process which places an upper bound to the 3He polarization that can be achieved. Additional spin relaxation mechanisms might exist due to the high gas temperature, which could explain the origin of the X-factor.

ISO far-infrared observations of rich galaxy clusters II. Sersic 159-03

DEFF Research Database (Denmark)

Hansen, Lene; Jørgensen, H.E.; Nørgaard-Nielsen, Hans Ulrik

2000-01-01

In a series of papers we investigate far-infrared emission from rich galaxy clusters. Maps have been obtained by ISO at 60 mu m, 100 mu m, 135 mu m, and 200 mu m using the PHT-C camera. Ground based imaging and spectroscopy were also acquired. Here we present the results for the cooling flow...

A novel, highly efficient cavity backshort design for far-infrared TES detectors

Science.gov (United States)

Bracken, C.; de Lange, G.; Audley, M. D.; Trappe, N.; Murphy, J. A.; Gradziel, M.; Vreeling, W.-J.; Watson, D.

2018-03-01

In this paper we present a new cavity backshort design for TES (transition edge sensor) detectors which will provide increased coupling of the incoming astronomical signal to the detectors. The increased coupling results from the improved geometry of the cavities, where the geometry is a consequence of the proposed chemical etching manufacturing technique. Using a number of modelling techniques, predicted results of the performance of the cavities for frequencies of 4.3-10 THz are presented and compared to more standard cavity designs. Excellent optical efficiency is demonstrated, with improved response flatness across the band. In order to verify the simulated results, a scaled model cavity was built for testing at the lower W-band frequencies (75-100 GHz) with a VNA system. Further testing of the scale model at THz frequencies was carried out using a globar and bolometer via an FTS measurement set-up. The experimental results are presented, and compared to the simulations. Although there is relatively poor comparison between simulation and measurement at some frequencies, the discrepancies are explained by means of higher-mode excitation in the measured cavity which are not accounted for in the single-mode simulations. To verify this assumption, a better behaved cylindrical cavity is simulated and measured, where excellent agreement is demonstrated in those results. It can be concluded that both the simulations and the supporting measurements give confidence that this novel cavity design will indeed provide much-improved optical coupling for TES detectors in the far-infrared/THz band.

Direct observation of the discrete energy spectrum of two lanthanide-based single-chain magnets by far-infrared spectroscopy

Science.gov (United States)

Haas, Sabrina; Heintze, Eric; Zapf, Sina; Gorshunov, Boris; Dressel, Martin; Bogani, Lapo

2014-05-01

The far-infrared optical transmission has been studied for two lanthanide-based single-chain magnets DyPhOPh and TbPhOPh in the frequency range between 3 and 80 cm-1. The spectra were acquired at temperatures between 2 and 80 K and magnetic fields up to 6 T. Based on their magnetic field dependence in DyPhOPh two of the observed absorption lines are identified as transitions inside the crystal field split Dy3+ ground multiplet 6H15/2, coupled to the neighboring spins. In TbPhOPh one transition was observed inside the crystal-field-split Tb3+ ground multiplet 7F6. The results allow a spectroscopic investigation of the role of single-ion anisotropy and exchange in Glauber dynamics.

Far infrared radiation (FIR): its biological effects and medical applications.

Science.gov (United States)

Vatansever, Fatma; Hamblin, Michael R

2012-11-01

Far infrared (FIR) radiation (λ = 3-100 μm) is a subdivision of the electromagnetic spectrum that has been investigated for biological effects. The goal of this review is to cover the use of a further sub-division (3- 12 μm) of this waveband, that has been observed in both in vitro and in vivo studies, to stimulate cells and tissue, and is considered a promising treatment modality for certain medical conditions. Technological advances have provided new techniques for delivering FIR radiation to the human body. Specialty lamps and saunas, delivering pure FIR radiation (eliminating completely the near and mid infrared bands), have became safe, effective, and widely used sources to generate therapeutic effects. Fibers impregnated with FIR emitting ceramic nanoparticles and woven into fabrics, are being used as garments and wraps to generate FIR radiation, and attain health benefits from its effects.

Twisting Anderson pseudospins with light: Quench dynamics in THz-pumped BCS superconductors

Science.gov (United States)

Chou, Yang-Zhi; Liao, Yunxiang; Foster, Matthew

We study the preparation and the detection of coherent far-from-equilibrium BCS superconductor dynamics in THz pump-probe experiments. In a recent experiment, an intense monocycle THz pulse with center frequency ω = Δ was injected into a superconductor with BCS gap Δ the post-pump evolution was detected via the optical conductivity. It was argued that nonlinear coupling of the pump to the Anderson pseudospins of the superconductor induces coherent dynamics of the Higgs mode Δ (t) . We validate this picture in a 2D BCS model with a combination of exact numerics and the Lax reduction, and we compute the dynamical phase diagram. The main effect of the pump is to scramble the orientations of Anderson pseudospins along the Fermi surface by twisting them in the xy-plane. We show that more intense pulses can induce a far-from-equilibrium gapless phase (phase I), originally predicted in the context of interaction quenches. We show that the THz pump can reach phase I at much lower energy densities than an interaction quench, and we demonstrate that Lax reduction provides a quantitative tool for computing coherent BCS dynamics. We also compute the optical conductivity for the states discussed here.

Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy

International Nuclear Information System (INIS)

Fischer, B M; Walther, M; Jepsen, P Uhd

2002-01-01

The far-infrared dielectric function of a wide range of organic molecules is dominated by vibrations involving a substantial fraction of the atoms forming the molecule and motion associated with intermolecular hydrogen bond vibrations. Due to their collective nature such modes are highly sensitive to the intra- and intermolecular structure and thus provide a unique fingerprint of the conformational state of the molecule and effects of its environment. We demonstrate the use of terahertz time-domain spectroscopy (THz-TDS) for recording the far-infrared (0.5-4.0 THz) dielectric function of the four nucleobases and corresponding nucleosides forming the building blocks of deoxyribose nucleic acid (DNA). We observe numerous distinct spectral features with large differences between the molecules in both frequency-dependent absorption coefficient and index of refraction. Assisted by results from density-functional calculations we interpret the origin of the observed resonances as vibrations of hydrogen bonds between the molecules

Estimate of Radiosonde Dry Bias From Far-Infrared Measurements on the Antarctic Plateau

Science.gov (United States)

Rizzi, R.; Maestri, T.; Arosio, C.

2018-03-01

The experimental data set of downwelling radiance spectra measured at the ground in clear conditions during 2013 by a Far-Infrared Fourier Transform Spectrometer at Dome-C, Antarctica, presented in Rizzi et al. (2016, https://doi.org/10.1002/2016JD025341) is used to estimate the effect of solar heating of the radiosonde humidity sensor, called dry bias. The effect is quite evident comparing residuals for the austral summer and winter clear cases and can be modeled by an increase of the water vapor concentration at all levels by about 15%. Such an estimate has become possible only after a new version of the simulation code and spectroscopic data has become available, which has substantially improved the modeling of water vapor absorption in the far infrared. The negative yearly spectral bias reported in Rizzi et al. (2016, https://doi.org/10.1002/2016JD025341) is in fact greatly reduced when compared to the same measurement data set.

High speed FPGA-based Phasemeter for the far-infrared laser interferometers on EAST

Science.gov (United States)

Yao, Y.; Liu, H.; Zou, Z.; Li, W.; Lian, H.; Jie, Y.

2017-12-01

The far-infrared laser-based HCN interferometer and POlarimeter/INTerferometer\\break (POINT) system are important diagnostics for plasma density measurement on EAST tokamak. Both HCN and POINT provide high spatial and temporal resolution of electron density measurement and used for plasma density feedback control. The density is calculated by measuring the real-time phase difference between the reference beams and the probe beams. For long-pulse operations on EAST, the calculation of density has to meet the requirements of Real-Time and high precision. In this paper, a Phasemeter for far-infrared laser-based interferometers will be introduced. The FPGA-based Phasemeter leverages fast ADCs to obtain the three-frequency signals from VDI planar-diode Mixers, and realizes digital filters and an FFT algorithm in FPGA to provide real-time, high precision electron density output. Implementation of the Phasemeter will be helpful for the future plasma real-time feedback control in long-pulse discharge.

Simultaneous optical and infrared polarization measurements of blazars

International Nuclear Information System (INIS)

Brindle, C.; Hough, J.H.; Bailey, J.A.; Axon, D.J.; Hyland, A.R.

1986-01-01

Measurements are presented of the polarization and flux of a sample of 28 blazars (21 BL Lacs and 7 OVV quasars) at optical and near-infrared wavelengths, with repeated observations for some objects. For 20 objects, these are the first reported polarization measurements in either the optical or infrared, and for most of them the first simultaneous measurements at these wavelengths. Out of a total of 42 observations a spectral dependence of polarization level and position angle is found, although not necessarily occurring together, on 15 occasions. (author)

The Relationship Between Dynamics and Structure in the Far Infrared Absorption Spectrum of Liquid Water

Energy Technology Data Exchange (ETDEWEB)

Woods, K.

2005-01-14

Using an intense source of far-infrared radiation, the absorption spectrum of liquid water is measured at a temperature ranging from 269 to 323 K. In the infrared spectrum we observe modes that are related to the local structure of liquid water. Here we present a FIR measured spectrum that is sensitive to the low frequency (< 100cm{sup -1}) microscopic details that exist in liquid water.

Chalcogenide Glass Optical Waveguides for Infrared Biosensing

Directory of Open Access Journals (Sweden)

Bruno Bureau

2009-09-01

Full Text Available Due to the remarkable properties of chalcogenide (Chg glasses, Chg optical waveguides should play a significant role in the development of optical biosensors. This paper describes the fabrication and properties of chalcogenide fibres and planar waveguides. Using optical fibre transparent in the mid-infrared spectral range we have developed a biosensor that can collect information on whole metabolism alterations, rapidly and in situ. Thanks to this sensor it is possible to collect infrared spectra by remote spectroscopy, by simple contact with the sample. In this way, we tried to determine spectral modifications due, on the one hand, to cerebral metabolism alterations caused by a transient focal ischemia in the rat brain and, in the other hand, starvation in the mouse liver. We also applied a microdialysis method, a well known technique for in vivo brain metabolism studies, as reference. In the field of integrated microsensors, reactive ion etching was used to pattern rib waveguides between 2 and 300 μm wide. This technique was used to fabricate Y optical junctions for optical interconnections on chalcogenide amorphous films, which can potentially increase the sensitivity and stability of an optical micro-sensor. The first tests were also carried out to functionalise the Chg planar waveguides with the aim of using them as (biosensors.

Drunk identification using far infrared imagery based on DCT features in DWT domain

Science.gov (United States)

Xie, Zhihua; Jiang, Peng; Xiong, Ying; Li, Ke

2016-10-01

Drunk driving problem is a serious threat to traffic safety. Automatic drunk driver identification is vital to improve the traffic safety. This paper copes with automatic drunk driver detection using far infrared thermal images by the holistic features. To improve the robustness of drunk driver detection, instead of traditional local pixels, a holistic feature extraction method is proposed to attain compact and discriminative features for infrared face drunk identification. Discrete cosine transform (DCT) in discrete wavelet transform (DWT) domain is used to extract the useful features in infrared face images for its high speed. Then, the first six DCT coefficients are retained for drunk classification by means of "Z" scanning. Finally, SVM is applied to classify the drunk person. Experimental results illustrate that the accuracy rate of proposed infrared face drunk identification can reach 98.5% with high computation efficiency, which can be applied in real drunk driver detection system.

A Phase-Controlled Optical Parametric Amplifier Pumped by Two Phase-Distorted Laser Beams

International Nuclear Information System (INIS)

Hong-Yan, Ren; Lie-Jia, Qian; Peng, Yuan; He-Yuan, Zhu; Dian-Yuan, Fan

2010-01-01

We theoretically study the phase characteristic of optical parametric amplification (OPA) or chirped pulse OPA (OPCPA) pumped by two phase-distorted laser beams. In the two-beam-pumped optical parametric amplification (TBOPA), due to spatial walk-off, both of the pump phase distortions will be partly transferred to signal in a single crystal so as to degrade the signal beam-quality, which will be more serious in high-energy OPCPA. An OPA configuration with a walkoff-compensated crystal pair is demonstrated for reducing the signal phase distortion experienced in the first stage and ensuring the signal phase independent of two pump phase distortions through the second crystal, hence maintaining the signal beam-quality. Such a TBOPA is similar to the conventional quantum laser amplifier by means of eliminating its sensitivity to the phase and number of the pump beams

Optical silencing of C. elegans cells with light-driven proton pumps.

Science.gov (United States)

Okazaki, Ayako; Takahashi, Megumi; Toyoda, Naoya; Takagi, Shin

2014-08-01

Recent development of optogenetic techniques, which utilize light-driven ion channels or ion pumps for controlling the activity of excitable cells, has greatly facilitated the investigation of nervous systems in vivo. A new generation of optical silencers includes outward-directed proton pumps, such as Arch, which have several advantages over currently widely used halorhodopsin (NpHR). These advantages include the resistance to inactivation during prolonged illumination and the ability to generate a larger optical current from low intensity light. C. elegans, with its small transparent body and well-characterized neural circuits, is especially suitable for optogenetic analyses. In this article, we will outline the practical aspects of using of Arch and other proton pumps as optogenetic tools in C. elegans. Copyright © 2014 Elsevier Inc. All rights reserved.

Infrared Line Intensities for Formaldehyde from Simultaneous Measurements in the Infrared and Far Infrared Spectral Ranges

Science.gov (United States)

Fissiaux, L.; Földes, T.; Tchana, F. Kwabia; Daumont, L.; Lepère, M.; Vander Auwera, J.

2011-06-01

Formaldehyde (H_2CO) is an important intermediate compound in the degradation of the volatile organic compounds (VOCs), including methane, in the terrestrial troposphere. Its observation using optical remote sensing in the infrared range relies on the 3.6 and 5.7 μm absorption bands. Band and individual line intensities have been reported in both ranges. With the present work, we aim to also derive infrared line intensities for formaldehyde, however relying on pure rotation line intensities and the known electric dipole moment to determine the particle density. Indeed, because formaldehyde polymerizes or degrades easily, the gas phase may contain polymerization or degradation products. Spectra of H_2CO diluted in 10 hPa of N_2 were therefore simultaneously recorded in the 20-60 Cm-1 and 3.6 μm ranges, respectively using a Bruker IFS125HR Fourier transform spectrometer and a tunable diode laser. see A. Perrin, D. Jacquemart, F. Kwabia Tchana, N. Lacome, J. Quant. Spectrosc. Radiat. Transfer 110 (2009) 700-716, and references therein

Near-simultaneous optical and infrared spectrophotometry of active galaxies

International Nuclear Information System (INIS)

Yates, M.G.; Garden, R.P.

1989-01-01

We present optical and infrared spectrophotometry for a sample of eight optically bright quasars, and the broad-line radio galaxy (BLRG) 3C 120. The optical and infrared spectrophotometry is separated by only five weeks, thus we have been able to minimize uncertainties due to variations in the objects. We compare our observed Paα/Hα and Hα/Hβ ratios with a large number of current photoionization models. We find that none of these models are able to reproduce our observed values of Paα/Hα in any of the active galaxies except the quasars 3C 273 and 0736+017. (author)

77 FR 27081 - II-VI, Incorporated, Infrared Optics-Saxonburg Division, Saxonburg, Pennsylvania; Notice of...

Science.gov (United States)

2012-05-08

..., Infrared Optics--Saxonburg Division, Saxonburg, Pennsylvania; Notice of Affirmative Determination Regarding... Assistance (TAA) applicable to workers and former workers of II-VI, Incorporated, Infrared Optics--Saxonburg...). The workers were engaged in employment related to the production of infrared and CO 2 laser optics...

Infrared studies of the S235 molecular cloud

International Nuclear Information System (INIS)

Evans, N.J. II; Beichman, C.; Gatley, I.; Harvey, P.; Nadeau, D.; Sellgren, K.

1981-01-01

Infrared observations from 7.8 to 200 μm have been obtained for the S235 molecular cloud. Far-infrared maps were obtained for a region of active star formation, as marked by the presence of compact H II regions, water masers, and compact near-infrared sources. The primary heating source for the far-infrared emission appears to be the compact H II region, S235A. Detailed examination of the gas energetics in the region supports the plausibility of the picture in which the gas is heated by collisions with warm dust grains. The ratio of far-infrared optical depth to 13 CO column density is somewhat lower in this source than is commonly found. This effect may be caused by the presence of substantial 13 CO in regions where the dust is not warm enough to emit substantial 50--100 μm radiation

An experimental study about effect of far infrared radiant ceramics on efficient methane fermentation

International Nuclear Information System (INIS)

Oda, A.; Yamazaki, M.; Oida, A.

2003-01-01

Methane fermentation, well known as one of the methods for organic wastes treatment, has been used as an energy production process in order to produce a gaseous fuel. But methane fermentation has some problems to be solved about gas production rate and volatile solids reduction efficiency. Simple methods to improve these problems are needed. In this study, we focused on far infrared radiant ceramics as a stimulating substance to activate methanogenic bacteria. Firstly, through the experiment of one batch fermentation, it was confirmed that the ceramics in the fermenter caused increase of total gas production. Next, even through the experiment of continuous fermentation, same stimulating effect was confirmed. It was considered that this effect was caused not only by a function of bio-contactor of the ceramics but also by far infrared radiation from ceramics. (author)

Optical silencing of body wall muscles induces pumping inhibition in Caenorhabditis elegans

OpenAIRE

Takahashi, Megumi; Takagi, Shin

2017-01-01

Feeding, a vital behavior in animals, is modulated depending on internal and external factors. In the nematode Caenorhabditis elegans, the feeding organ called the pharynx ingests food by pumping driven by the pharyngeal muscles. Here we report that optical silencing of the body wall muscles, which drive the locomotory movement of worms, affects pumping. In worms expressing the Arch proton pump or the ACR2 anion channel in the body wall muscle cells, the pumping rate decreases after activatio...

Optics of Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII): Delay Lines and Alignment

Science.gov (United States)

Dhabal, Arnab; Rinehart, Stephen A.; Rizzo, Maxime J.; Mundy, Lee; Fixsen, Dale; Sampler, Henry; Mentzell, Eric; Veach, Todd; Silverberg, Robert F.; Furst, Stephen;

Detection of quadrupole relaxation in an optically pumped cesium vapour

Energy Technology Data Exchange (ETDEWEB)

Bernabeu, E; Tornos, J

1985-10-01

The relaxation of quadrupole orientation induced by means of optical pumping in a cesium vapour is experimentally studied, and the results are compared to the theoretical predictions. The optical detection process of this type of orientation is also discussed as a function of the polarization and spectral profile of the detection light.

SEASONAL DISAPPEARANCE OF FAR-INFRARED HAZE IN TITAN'S STRATOSPHERE

Energy Technology Data Exchange (ETDEWEB)

Jennings, Donald E.; Anderson, C. M.; Flasar, F. M.; Cottini, V. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Samuelson, R. E.; Nixon, C. A.; Kunde, V. G.; Achterberg, R. K. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); De Kok, R. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Coustenis, A.; Vinatier, S. [LESIA, Observatoire de Paris-Meudon, 92195 Meudon Cedex (France); Calcutt, S. B., E-mail: donald.e.jennings@nasa.gov [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

2012-07-20

A far-infrared emission band attributed to volatile or refractory haze in Titan's stratosphere has been decreasing in intensity since Cassini's arrival in 2004. The 220 cm{sup -1} feature, first seen by the Voyager Infrared Interferometer Spectrometer, has only been found in Titan's winter polar region. The emission peaks at about 140 km altitude near the winter stratospheric temperature minimum. Observations recorded over the period 2004-2012 by the Composite Infrared Spectrometer on Cassini show a decrease in the intensity of this feature by about a factor of four. Possible seasonal causes of this decline are an increase in photolytic destruction of source chemicals at high altitude, a lessening of condensation as solar heating increased, or a weakening of downwelling of vapors. As of early 2012, the 220 cm{sup -1} haze has not yet been detected in the south. The haze composition is unknown, but its decrease is similar to that of HC{sub 3}N gas in Titan's polar stratosphere, pointing to a nitrile origin.

A combined optical, infrared and radio study of the megamaser galaxy III Zw 35

International Nuclear Information System (INIS)

Chapman, J.M.; Axon, D.J.; Cohen, R.J.; Pedlar, A.; Davies, R.D.; Unger, S.W.

1990-01-01

III Zw 35 is a pair of galaxies characterized by powerful radio continuum, far-infrared and OH maser radiation. We have made a multi-frequency study of the galaxy pair based on optical, infrared and radio observations. The brighter northern component is identified as an early-type LINER or Seyfert galaxy containing an active nuclear region from which radio continuum, OH maser and thermal dust emission are detected. We propose that the northern component has a compact active nucleus deeply embedded in a highly obscured region of diameter ∼ 210 pc, within which enhanced star-formation occurs. The lower luminosity southern component is of low mass and is undergoing starburst activity over an extended region of diameter ∼ 5.5 kpc. The origin of the starburst and non-thermal activity appears to be an interaction between the two components. (author)

Using optic flow in the far peripheral field.

Science.gov (United States)

McManus, Meaghan; D'Amour, Sarah; Harris, Laurence R

2017-07-01

Self-motion information can be used to update spatial memory of location through an estimate of a change in position. Viewing optic flow alone can create Illusory self-motion or "vection." Early studies suggested that peripheral vision is more effective than central vision in evoking vection, but controlling for retinal area and perceived distance suggests that all retinal areas may be equally effective. However, the contributions of the far periphery, beyond 90°, have been largely neglected. Using a large-field Edgeless Graphics Geometry display (EGG, Christie, Canada, field of view ±112°) and systematically blocking central (±20° to ±90°) or peripheral (viewing through tunnels ±20° to ±40°) parts of the field, we compared the effectiveness of different retinal regions at evoking forwards linear vection. Fifteen participants indicated when they had reached the position of a previously presented target after visually simulating motion down a simulated corridor. The amount of simulated travel needed to match a given target distance was modelled with a leaky spatial integrator model to estimate gains (perceived/actual distance) and a spatial decay factor. When optic flow was presented only in the far periphery (beyond 90°) gains were significantly higher than for the same motion presented full field or in only the central field, resulting in accurate performance in the range of speeds associated with normal walking. The increased effectiveness of optic flow in the peripheral field alone compared to full-field motion is discussed in terms of emerging neurophysiological studies that suggest brain areas dedicated to processing information from the far peripheral field.

Studies on optical pumping cells (OPC) to polarize 3He

International Nuclear Information System (INIS)

Hutanu, V.; Rupp, A.

2004-01-01

The technique applied at HMI to obtain nuclear-spin-polarized 3 He, used in neutron spin filters (NSFs), is metastability-exchange optical pumping. To prepare efficient NSF, one must highly polarize 3 He nuclei in the optical pumping volume (OPV) and reduce the polarization losses during the compression phase. Great progress has been achieved in reducing of depolarization due to the recent development of both, large polarization preserving piston compressors and long relaxation time filter cells. It is even more important to significantly enhance the 3 He polarization rate during optical pumping in order to increase NSF efficiency. Different cells materials were tested, such as Duran and quartz glass. In order to use the laser light more efficiently and to decrease the risk of 3 He depolarization due to unfavorable reflections, antireflection (AR) coatings were used on cell windows made of quartz glass. They were compared with the ones without coating, made of quartz, Duran and BK7 glass. The comparison of various techniques to mount the windows such as blowing, gluing or molecular diffusion was also conducted. It indicated that the molecular diffusion is the most suitable technique because of a better purity of the gas in the cell and the preservation of the optical flatness of the windows. Cells, for practical reasons each entirely made from the same material (Duran, Quartz glass) with windows mounted using this method, showed the best polarization performance

Efficacy and safety of far infrared radiation in lymphedema treatment: clinical evaluation and laboratory analysis.

Science.gov (United States)

Li, Ke; Zhang, Zheng; Liu, Ning Fei; Feng, Shao Qing; Tong, Yun; Zhang, Ju Fang; Constantinides, Joannis; Lazzeri, Davide; Grassetti, Luca; Nicoli, Fabio; Zhang, Yi Xin

2017-04-01

Swelling is the most common symptom of extremities lymphedema. Clinical evaluation and laboratory analysis were conducted after far infrared radiation (FIR) treatment on the main four components of lymphedema: fluid, fat, protein, and hyaluronan. Far infrared radiation is a kind of hyperthermia therapy with several and additional benefits as well as promoting microcirculation flow and improving collateral lymph circumfluence. Although FIR therapy has been applied for several years on thousands of lymphedema patients, there are still few studies that have reported the biological effects of FIR on lymphatic tissue. In this research, we investigate the effects of far infrared rays on the major components of lymphatic tissue. Then, we explore the effectiveness and safety of FIR as a promising treatment modality of lymphedema. A total of 32 patients affected by lymphedema in stage II and III were treated between January 2015 and January 2016 at our department. After therapy, a significant decrease of limb circumference measurements was noted and improving of quality of life was registered. Laboratory examination showed the treatment can also decrease the deposition of fluid, fat, hyaluronan, and protein, improving the swelling condition. We believe FIR treatment could be considered as both an alternative monotherapy and a useful adjunctive to the conservative or surgical lymphedema procedures. Furthermore, the real and significant biological effects of FIR represent possible future applications in wide range of the medical field.

Effects of Somatothermal Far-Infrared Ray on Primary Dysmenorrhea: A Pilot Study

Directory of Open Access Journals (Sweden)

Yu-Min Ke

2012-01-01

Full Text Available The purpose of this study was to assess the beneficial effects of using a far-infrared (FIR belt on the management of patients with primary dysmenorrhea. This is the first study to determine the efficacy of somatothermal FIR using a parallel-arm randomized sham-controlled and double-blinded design with objective physical evidence and psychometric self-reports. Fifty-one Taiwanese women with primary dysmenorrhea were enrolled in the study. Results indicate that there was an increased abdominal temperature of 0.6°C and a 3.27% increase in abdominal blood flow in the FIR group (wearing FIR belt compared to those in the control group (wearing sham belt. Verbal rating scale and numeric rating scale scores in the FIR group were both lower than those in the control group. Compared to the blank group (wearing no belt, the average dysmenorrhea pain duration of the FIR group was significantly reduced from 2.5 to 1.8 days, but there was no significant difference in the control group. These results demonstrate that the use of a belt made of far-infrared ceramic materials can reduce primary dysmenorrhea.

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.

Two-tint pump-probe measurements using a femtosecond laser oscillator and sharp-edged optical filters.

Science.gov (United States)

Kang, Kwangu; Koh, Yee Kan; Chiritescu, Catalin; Zheng, Xuan; Cahill, David G

2008-11-01

We describe a simple approach for rejecting unwanted scattered light in two types of time-resolved pump-probe measurements, time-domain thermoreflectance (TDTR) and time-resolved incoherent anti-Stokes Raman scattering (TRIARS). Sharp edged optical filters are used to create spectrally distinct pump and probe beams from the broad spectral output of a femtosecond Ti:sapphire laser oscillator. For TDTR, the diffusely scattered pump light is then blocked by a third optical filter. For TRIARS, depolarized scattering created by the pump is shifted in frequency by approximately 250 cm(-1) relative to the polarized scattering created by the probe; therefore, spectral features created by the pump and probe scattering can be easily distinguished.

Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source

International Nuclear Information System (INIS)

Venkatraman, V.; Kang, S.; Affolderbach, C.; Mileti, G.; Shea, H.

2014-01-01

Miniature ( 3 ) vapor-cell based devices using optical pumping of alkali atoms, such as atomic clocks and magnetometers, today mostly employ vertical-cavity surface-emitting lasers as pump light sources. Here, we report on the demonstration of optical pumping in a microfabricated alkali vapor resonance cell using (1) a microfabricated Rb discharge lamp light source, as well as (2) a conventional glass-blown Rb discharge lamp. The microfabricated Rb lamp cell is a dielectric barrier discharge (DBD) light source, having the same inner cell volume of around 40 mm 3 as that of the resonance cell, both filled with suitable buffer gases. A miniature (∼2 cm 3 volume) test setup based on the M z magnetometer interrogation technique was used for observation of optical-radiofrequency double-resonance signals, proving the suitability of the microfabricated discharge lamp to introduce efficient optical pumping. The pumping ability of this light source was found to be comparable to or even better than that of a conventional glass-blown lamp. The reported results indicate that the micro-fabricated DBD discharge lamp has a high potential for the development of a new class of miniature atomic clocks, magnetometers, and quantum sensors

Twisting Anderson pseudospins with light: Quench dynamics in THz-pumped BCS superconductors

OpenAIRE

Chou, Yang-Zhi; Liao, Yunxiang; Foster, Matthew S.

2016-01-01

We study the preparation (pump) and the detection (probe) of far-from-equilibrium BCS superconductor dynamics in THz pump-probe experiments. In a recent experiment [R. Matsunaga, Y. I. Hamada, K. Makise, Y. Uzawa, H. Terai, Z. Wang, and R. Shimano, Phys. Rev. Lett. {\\bf 111}, 057002 (2013)], an intense monocycle THz pulse with center frequency $\\omega \\simeq \\Delta$ was injected into a superconductor with BCS gap $\\Delta$; the subsequent post-pump evolution was detected via the optical conduc...

Space imaging infrared optical guidance for autonomous ground vehicle

Science.gov (United States)

Akiyama, Akira; Kobayashi, Nobuaki; Mutoh, Eiichiro; Kumagai, Hideo; Yamada, Hirofumi; Ishii, Hiromitsu

2008-08-01

We have developed the Space Imaging Infrared Optical Guidance for Autonomous Ground Vehicle based on the uncooled infrared camera and focusing technique to detect the objects to be evaded and to set the drive path. For this purpose we made servomotor drive system to control the focus function of the infrared camera lens. To determine the best focus position we use the auto focus image processing of Daubechies wavelet transform technique with 4 terms. From the determined best focus position we transformed it to the distance of the object. We made the aluminum frame ground vehicle to mount the auto focus infrared unit. Its size is 900mm long and 800mm wide. This vehicle mounted Ackerman front steering system and the rear motor drive system. To confirm the guidance ability of the Space Imaging Infrared Optical Guidance for Autonomous Ground Vehicle we had the experiments for the detection ability of the infrared auto focus unit to the actual car on the road and the roadside wall. As a result the auto focus image processing based on the Daubechies wavelet transform technique detects the best focus image clearly and give the depth of the object from the infrared camera unit.

Electronic displays using optically pumped luminescent semiconductor nanocrystals

Science.gov (United States)

Weiss, Shimon [Pinole, CA; Schlamp, Michael C [Plainsboro, NJ; Alivisatos, A Paul [Oakland, CA

2011-09-27

A multicolor electronic display is based on an array of luminescent semiconductor nanocrystals. Nanocrystals which emit light of different colors are grouped into pixels. The nanocrystals are optically pumped to produce a multicolor display. Different sized nanocrystals are used to produce the different colors. A variety of pixel addressing systems can be used.

77 FR 21586 - II-VI, Incorporated, Infrared Optics-Saxonburg Division, Saxonburg, PA; Notice of Affirmative...

Science.gov (United States)

2012-04-10

..., Infrared Optics--Saxonburg Division, Saxonburg, PA; Notice of Affirmative Determination Regarding... Assistance (TAA) applicable to workers and former workers of II-VI, Incorporated, Infrared Optics--Saxonburg...). The workers were engaged in employment related to the production of infrared and CO 2 laser optics...

Infrared-faint radio sources remain undetected at far-infrared wavelengths. Deep photometric observations using the Herschel Space Observatory

Science.gov (United States)

Herzog, A.; Norris, R. P.; Middelberg, E.; Spitler, L. R.; Leipski, C.; Parker, Q. A.

2015-08-01

Context. Showing 1.4 GHz flux densities in the range of a few to a few tens of mJy, infrared-faint radio sources (IFRS) are a type of galaxy characterised by faint or absent near-infrared counterparts and consequently extreme radio-to-infrared flux density ratios up to several thousand. Recent studies showed that IFRS are radio-loud active galactic nuclei (AGNs) at redshifts ≳2, potentially linked to high-redshift radio galaxies (HzRGs). Aims: This work explores the far-infrared emission of IFRS, providing crucial information on the star forming and AGN activity of IFRS. Furthermore, the data enable examining the putative relationship between IFRS and HzRGs and testing whether IFRS are more distant or fainter siblings of these massive galaxies. Methods: A sample of six IFRS was observed with the Herschel Space Observatory between 100 μm and 500 μm. Using these results, we constrained the nature of IFRS by modelling their broad-band spectral energy distribution (SED). Furthermore, we set an upper limit on their infrared SED and decomposed their emission into contributions from an AGN and from star forming activity. Results: All six observed IFRS were undetected in all five Herschel far-infrared channels (stacking limits: σ = 0.74 mJy at 100 μm, σ = 3.45 mJy at 500 μm). Based on our SED modelling, we ruled out the following objects to explain the photometric characteristics of IFRS: (a) known radio-loud quasars and compact steep-spectrum sources at any redshift; (b) starburst galaxies with and without an AGN and Seyfert galaxies at any redshift, even if the templates were modified; and (c) known HzRGs at z ≲ 10.5. We find that the IFRS analysed in this work can only be explained by objects that fulfil the selection criteria of HzRGs. More precisely, IFRS could be (a) known HzRGs at very high redshifts (z ≳ 10.5); (b) low-luminosity siblings of HzRGs with additional dust obscuration at lower redshifts; (c) scaled or unscaled versions of Cygnus A at any

Far-infrared Fourier Transform Spectroscopy Measurements of Mn12-acetate.

Science.gov (United States)

Tu, Jiufeng; Suzuki, Yoko; Mertes, K. M.; Sarachik, M. P.; Agladze, N. I.; Sievers, A. J.; Rumberger, E. M.; Hendrickson, D. N.; Christou, G.

2004-03-01

The transmission spectra of both powder samples and assemblies of single crystals of Mn_12-acetate were measured in the far infrared region (2.0 - 20 cm-1) using a Fourier transform technique. The energies of the observed aborption lines agree with those obtained by Mukhin et al. [1] using the backwards wave oscillator technique. The temperature dependence of the aborption lines, as well as the presence of additional absorption lines, will be discussed. [1] A. A. Mukhin, V. D. Travkin, A. K. Zvesdin, A. Caneschi, D. Gatteschi and R. Sessoli, Physica B 284-288 (2000) 1221-1222

Consideration of the Verleur model of far-infrared spectroscopy of ternary compounds

International Nuclear Information System (INIS)

Robouch, B. V.; Kisiel, A.; Sheregii, E. M.

2001-01-01

The clustering model proposed by Verleur and Barker [Phys. Rev. 149, 715 (1966)] to interpret far infrared data for face-centered-cubic ternary compounds is critically analyzed. It is shown that their approach, satisfactory for fitting some ternary compound spectral curves, is too restricted by its one-parameter β model to be able to describe preferences (with respect to a random distribution case) for the five tetrahedron configurations

Far-IR transparency and dynamic infrared signature control with novel conducting polymer systems

Science.gov (United States)

Chandrasekhar, Prasanna; Dooley, T. J.

1995-09-01

Materials which possess transparency, coupled with active controllability of this transparency in the infrared (IR), are today an increasingly important requirement, for varied applications. These applications include windows for IR sensors, IR-region flat panel displays used in camouflage as well as in communication and sight through night-vision goggles, coatings with dynamically controllable IR-emissivity, and thermal conservation coatings. Among stringent requirements for these applications are large dynamic ranges (color contrast), 'multi-color' or broad-band characteristics, extended cyclability, long memory retention, matrix addressability, small area fabricability, low power consumption, and environmental stability. Among materials possessing the requirements for variation of IR signature, conducting polymers (CPs) appear to be the only materials with dynamic, actively controllable signature and acceptable dynamic range. Conventional CPs such as poly(alkyl thiophene), poly(pyrrole) or poly(aniline) show very limited dynamic range, especially in the far-IR, while also showing poor transparency. We have developed a number of novel CP systems ('system' implying the CP, the selected dopant, the synthesis method, and the electrolyte) with very wide dynamic range (up to 90% in both important IR regions, 3 - 5 (mu) and 8 - 12 (mu) ), high cyclability (to 105 cycles with less than 10% optical degradation), nearly indefinite optical memory retention, matrix addressability of multi-pixel displays, very wide operating temperature and excellent environmental stability, low charge capacity, and processability into areas from less than 1 mm2 to more than 100 cm2. The criteria used to design and arrive at these CP systems, together with representative IR signature data, are presented in this paper.

Rapid infrared and optical variability in the bright quasar 3C273

International Nuclear Information System (INIS)

Courvoisier, T.J.-L.; Robson, E.I.; Hughes, D.H.; Bouchet, P.; Schwarz, H.E.; Krisciunas, K.

1988-01-01

We have observed variations by a factor of two in the infrared flux from the bright quasar 3C273 on a timescale as short as one day. In February 1988, the behaviour of the source changed from having a stable infrared flux and slow optical variations to a state characterized by recurrent infrared and optical flaring. The optical variations were of several per cent per day, changing from increase to decrease approximately every week. The amplitude of the repeated optical flares was 30-40%. The data are consistent with re-injection/acceleration of electrons followed by rapid cooling. The inferred magnetic field is 0.7 gauss and the data are marginally consistent with no relativistic beaming. (author)

Long-slit optical spectroscopy of powerful far-infrared galaxies - The nature of the nuclear energy source

Science.gov (United States)

Armus, Lee; Heckman, Timothy M.; Miley, George K.

1989-01-01

Optical spectroscopic data are presented for a sample of 47 powerful far-IR galaxies chosen for IR spectral shape, and for six other IR-bright galaxies. The stellar absorption lines expected from a population of old stars are generally very weak in the nuclei of the galaxies. Very weak Mg I absorption is found in regions well off the nucleus, implying that the visible spectrum is dominated by young stars and not by an AGN. At least one, and probably five, of the galaxies have detectable WR emission features, providing additional evidence for a young stellar population. About 20 percent of the galaxies have strong Balmer absorption lines, indicating the presence of a substantial intermediate-age stellar population. The equivalent width of the H-alpha emission line can be modeled as arising from a mixture of a large young population and an intermediate-age population of stars.

Germanium blocked impurity band far infrared detectors

International Nuclear Information System (INIS)

Rossington, C.S.

1988-04-01

The infrared portion of the electromagnetic spectrum has been of interest to scientist since the eighteenth century when Sir William Herschel discovered the infrared as he measured temperatures in the sun's spectrum and found that there was energy beyond the red. In the late nineteenth century, Thomas Edison established himself as the first infrared astronomer to look beyond the solar system when he observed the star Arcturus in the infrared. Significant advances in infrared technology and physics, long since Edison's time, have resulted in many scientific developments, such as the Infrared Astronomy Satellite (IRAS) which was launched in 1983, semiconductor infrared detectors for materials characterization, military equipment such as night-vision goggles and infrared surveillance equipment. It is now planned that cooled semiconductor infrared detectors will play a major role in the ''Star Wars'' nuclear defense scheme proposed by the Reagan administration

Insights on proximity effect and multiphoton induced luminescence from gold nanospheres in far field optical microscopy

Energy Technology Data Exchange (ETDEWEB)

Borglin, Johan [Biomedical Photonics Group, Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Department of Physics, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Guldbrand, Stina [Department of Physics, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Evenbratt, Hanne [Pharmaceutical Technology, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Gothenburg (Sweden); Kirejev, Vladimir; Ericson, Marica B., E-mail: marica.ericson@chem.gu.se [Biomedical Photonics Group, Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Grönbeck, Henrik [Department of Applied Physics, Chalmers University of Technology, Kemivägen 9, 412 96 Gothenburg (Sweden)

2015-12-07

Gold nanoparticles can be visualized in far-field multiphoton laser-scanning microscopy (MPM) based on the phenomena of multiphoton induced luminescence (MIL). This is of interest for biomedical applications, e.g., for cancer diagnostics, as MPM allows for working in the near-infrared (NIR) optical window of tissue. It is well known that the aggregation of particles causes a redshift of the plasmon resonance, but its implications for MIL applying far-field MPM should be further exploited. Here, we explore MIL from 10 nm gold nanospheres that are chemically deposited on glass substrates in controlled coverage gradients using MPM operating in NIR range. The substrates enable studies of MIL as a function of inter-particle distance and clustering. It was shown that MIL was only detected from areas on the substrates where the particle spacing was less than one particle diameter, or where the particles have aggregated. The results are interpreted in the context that the underlying physical phenomenon of MIL is a sequential two-photon absorption process, where the first event is driven by the plasmon resonance. It is evident that gold nanospheres in this size range have to be closely spaced or clustered to exhibit detectable MIL using far-field MPM operating in the NIR region.

Insights on proximity effect and multiphoton induced luminescence from gold nanospheres in far field optical microscopy

International Nuclear Information System (INIS)

Borglin, Johan; Guldbrand, Stina; Evenbratt, Hanne; Kirejev, Vladimir; Ericson, Marica B.; Grönbeck, Henrik

2015-01-01

Gold nanoparticles can be visualized in far-field multiphoton laser-scanning microscopy (MPM) based on the phenomena of multiphoton induced luminescence (MIL). This is of interest for biomedical applications, e.g., for cancer diagnostics, as MPM allows for working in the near-infrared (NIR) optical window of tissue. It is well known that the aggregation of particles causes a redshift of the plasmon resonance, but its implications for MIL applying far-field MPM should be further exploited. Here, we explore MIL from 10 nm gold nanospheres that are chemically deposited on glass substrates in controlled coverage gradients using MPM operating in NIR range. The substrates enable studies of MIL as a function of inter-particle distance and clustering. It was shown that MIL was only detected from areas on the substrates where the particle spacing was less than one particle diameter, or where the particles have aggregated. The results are interpreted in the context that the underlying physical phenomenon of MIL is a sequential two-photon absorption process, where the first event is driven by the plasmon resonance. It is evident that gold nanospheres in this size range have to be closely spaced or clustered to exhibit detectable MIL using far-field MPM operating in the NIR region

Research and development on optically pumped polarized ion sources. Technical progress report, February 1, 1985-January 31, 1986

International Nuclear Information System (INIS)

Anderson, L.W.

1985-07-01

During the past year we have studied the relaxation times in an optically pumped 23 Na vapor target, studied the effects of radiation trapping on the polarization in a Na vapor target, and have studied the effects of spin exchange collisions on a beam of fast H 0 atoms as they pass through a polarized alkali target. This research is directed toward improvements in the optically pumped Na or other alkali vapor targets used for the production of polarized H - ions. In this progress report we review the properties of the optically pumped polarized H - ion source as well as discussing the progress of our research on optically pumped Na or other alkali vapor targets. 81 refs., 9 figs

Ultrafast far-infrared dynamics probed by terahertz pulses: A frequency-domain approach. II. Applications

Czech Academy of Sciences Publication Activity Database

Němec, Hynek; Kadlec, Filip; Kadlec, Christelle; Kužel, Petr; Jungwirth, Pavel

2005-01-01

Roč. 122, č. 10 (2005), 104504/1-104504/8 ISSN 0021-9606 R&D Projects: GA AV ČR(CZ) KJB100100512 Institutional research plan: CEZ:AV0Z10100520 Keywords : optical pump * terahertz probe Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.138, year: 2005

Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source

Energy Technology Data Exchange (ETDEWEB)

Venkatraman, V.; Kang, S.; Affolderbach, C.; Mileti, G., E-mail: gaetano.mileti@unine.ch [Laboratoire Temps-Fréquence, University of Neuchâtel, Neuchâtel 2000 (Switzerland); Shea, H. [Microsystems for Space Technologies Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel 2002 (Switzerland)

2014-02-03

Miniature (optical pumping of alkali atoms, such as atomic clocks and magnetometers, today mostly employ vertical-cavity surface-emitting lasers as pump light sources. Here, we report on the demonstration of optical pumping in a microfabricated alkali vapor resonance cell using (1) a microfabricated Rb discharge lamp light source, as well as (2) a conventional glass-blown Rb discharge lamp. The microfabricated Rb lamp cell is a dielectric barrier discharge (DBD) light source, having the same inner cell volume of around 40 mm{sup 3} as that of the resonance cell, both filled with suitable buffer gases. A miniature (∼2 cm{sup 3} volume) test setup based on the M{sub z} magnetometer interrogation technique was used for observation of optical-radiofrequency double-resonance signals, proving the suitability of the microfabricated discharge lamp to introduce efficient optical pumping. The pumping ability of this light source was found to be comparable to or even better than that of a conventional glass-blown lamp. The reported results indicate that the micro-fabricated DBD discharge lamp has a high potential for the development of a new class of miniature atomic clocks, magnetometers, and quantum sensors.

Optical pumping of hot phonons in GaAs

International Nuclear Information System (INIS)

Collins, C.L.; Yu, P.Y.

1982-01-01

Optical pumping of hot LO phonons in GaAs has been studied as a function of the excitation photon frequency. The experimental results are in good agreement with a model calculation which includes both inter- and intra-valley electron-phonon scatterings. The GAMMA-L and GAMMA-X intervalley electron-phonon interactions in GaAs have been estimated

Bio-inspired Plasmonic Nanoarchitectured Hybrid System Towards Enhanced Far Red-to-Near Infrared Solar Photocatalysis

OpenAIRE

Runyu Yan; Min Chen; Han Zhou; Tian Liu; Xingwei Tang; Ke Zhang; Hanxing Zhu; Jinhua Ye; Di Zhang; Tongxiang Fan

2016-01-01

Solar conversion to fuels or to electricity in semiconductors using far red-to-near infrared (NIR) light, which accounts for about 40% of solar energy, is highly significant. One main challenge is the development of novel strategies for activity promotion and new basic mechanisms for NIR response. Mother Nature has evolved to smartly capture far red-to-NIR light via their intelligent systems due to unique micro/nanoarchitectures, thus motivating us for biomimetic design. Here we report the fi...

Environmental Temperature Effect on the Far-Infrared Absorption Features of Aromatic-Based Titan's Aerosol Analogs

Science.gov (United States)

Gautier, Thomas; Trainer, Melissa G.; Loeffler, Mark J.; Sebree, Joshua A.; Anderson, Carrie M.

2016-01-01

Benzene detection has been reported in Titans atmosphere both in the stratosphere at ppb levels by remote sensing and in the thermosphere at ppm levels by the Cassini's Ion and Neutral Mass Spectrometer. This detection supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titans atmospheric chemistry, especially in the formation of aerosols. Indeed, aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation. It has been shown recently that aerosol analogs produced from a gas mixture containing a low concentration of aromatic and/or heteroaromatic molecules (benzene, naphthalene, pyridine, quinoline and isoquinoline) have spectral signatures below 500/cm, a first step towards reproducing the aerosol spectral features observed by Cassini's Composite InfraRed Spectrometer (CIRS) in the far infrared. In this work we investigate the influence of environmental temperature on the absorption spectra of such aerosol samples, simulating the temperature range to which aerosols, once formed, are exposed during their transport through Titans stratosphere. Our results show that environmental temperature does not have any major effect on the spectral shape of these aerosol analogs in the far-infrared, which is consistent with the CIRS observations.

Hybrid optical pumping of K and Rb atoms in a paraffin coated vapor cell

Science.gov (United States)

Li, Wenhao; Peng, Xiang; Budker, Dmitry; Wickenbrock, Arne; Pang, Bo; Zhang, Rui; Guo, Hong

2017-10-01

Dynamic hybrid optical pumping effects with a radio-frequency-field-driven nonlinear magneto-optical rotation (RF NMOR) scheme are studied in a dual-species paraffin coated vapor cell. By pumping K atoms and probing $^{87}$Rb atoms, we achieve an intrinsic magnetic resonance linewidth of 3 Hz and the observed resonance is immune to power broadening and light-shift effects. Such operation scheme shows favorable prospects for atomic magnetometry applications.

Integrative Multi-Spectral Sensor Device for Far-Infrared and Visible Light Fusion

Science.gov (United States)

Qiao, Tiezhu; Chen, Lulu; Pang, Yusong; Yan, Gaowei

2018-06-01

Infrared and visible light image fusion technology is a hot spot in the research of multi-sensor fusion technology in recent years. Existing infrared and visible light fusion technologies need to register before fusion because of using two cameras. However, the application effect of the registration technology has yet to be improved. Hence, a novel integrative multi-spectral sensor device is proposed for infrared and visible light fusion, and by using the beam splitter prism, the coaxial light incident from the same lens is projected to the infrared charge coupled device (CCD) and visible light CCD, respectively. In this paper, the imaging mechanism of the proposed sensor device is studied with the process of the signals acquisition and fusion. The simulation experiment, which involves the entire process of the optic system, signal acquisition, and signal fusion, is constructed based on imaging effect model. Additionally, the quality evaluation index is adopted to analyze the simulation result. The experimental results demonstrate that the proposed sensor device is effective and feasible.

Fiber-laser-based, green-pumped, picosecond optical parametric oscillator using fan-out grating PPKTP.

Science.gov (United States)

Chaitanya Kumar, S; Parsa, S; Ebrahim-Zadeh, M

2016-01-01

We report a stable, Yb-fiber-laser-based, green-pumped, picosecond optical parametric oscillator (OPO) for the near-infrared based on periodically poled potassium titanyl phosphate (PPKTP) nonlinear crystal, using fan-out grating design and operating near room temperature. The OPO is continuously tunable across 726-955 nm in the signal and 1201-1998 nm in the idler, resulting in a total signal plus idler wavelength coverage of 1026 nm by grating tuning at a fixed temperature. The device generates up to 580 mW of average power in the signal at 765 nm and 300 mW in the idler at 1338 nm, with an overall extraction efficiency of up to 52% and a pump depletion >76%. The extracted signal at 765 nm and idler at 1746 nm exhibit excellent passive power stability better than 0.5% and 0.8% rms, respectively, over 1 h with good beam quality in TEM00 mode profile. The output signal pulses have a Gaussian temporal duration of 13.2 ps, with a FWHM spectral bandwidth of 3.4 nm at 79.5 MHz repetition rate. Power scaling limitations of the OPO due to the material properties of PPKTP are studied.

Design of a far infrared interferometer diagnostic support structure

International Nuclear Information System (INIS)

Brooksby, C.A.; Rice, B.W.; Peebles, W.A.

1987-10-01

The Far Infrared Interferometer (FIR) diagnostic will operate in the 119 to 400 micron range to measure the plasma electron density on the Microwave Tokamak Experiment (MTX) being set up at LLNL. This diagnostic is a multi-channel system which incorporates a long elliptically shaped beam that passes through the plasma and is imaged onto an array of 14 detectors that are located on a table above the machine. The reference beam is brought around the machine and mixed with the plasma beam onto the detectors. The density is measured by a phase shift between these beams and is, therefore, very sensitive to path length changes between the two beam paths due to motion of the support structure. The design goal for allowable phase shifts caused by changes in the path length due to structure movement is 1/50th of a wavelength (2.4 to 8 microns). The structure needs to maintain this stability during the 0.5 second plasma shot. The structure is approximately 5 meters tall to support the optics table above the machine. In order to reduce the structure motion to the required level the forces acting on it were evaluated. The forces evaluated were eddy currents from the pulsed electromagnetic fields, the ambient ground motion, and the floor movement as the magnets are pulsed. The designs for similar diagnostic interferometers on other tokamaks were also reviewed to evaluate the forces and motions that might cause such small deflections in the support structure. Our structure is somewhat unique in that it is designed for operation in relatively large pulsed magnetic fields (100 to 7000 gauss) arising from the air core transformer of MTX. The design chosen incorporates a very rigid structure with high resistive and non-conductive materials. The choice of materials selected is discussed with reference to their response to expected forces. 14 refs., 10 figs

New infrared solid state laser materials for CALIOPE

International Nuclear Information System (INIS)

DeLoach, L.D.; Page, R.H.; Wilke, G.D.

1994-01-01

Tunable infrared laser light may serve as a useful means by which to detect the presence of the targeted effluents. Since optical parametric oscillators (OPOs) have proven to be a versatile method of generating coherent light from the ultraviolet to the mid-infrared, this technology is a promising choice by which to service the CALIOPE applications. In addition, since some uncertainty remains regarding the precise wavelengths and molecules that will be targeted, the deployment of OPOs retains the greatest amount of wavelength flexibility. Another approach that the authors are considering is that of generating tunable infrared radiation directly with a diode-pumped solid state laser (DPSSL). One important advantage of a DPSSL is that it offers flexible pulse format modes that can be tailored to meet the needs of a particular application and target molecule. On the other hand, direct generation by a tunable DPSSL will generally be able to cover a more limited wavelength range than is possible with OPO technology. In support of the CALIOPE objectives the authors are exploring the potential for laser action among a class of materials comprised of transition metal-doped zinc chalcogenide crystals (i.e., ZnS, ZnSe and ZnTe). The Cr 2+ , Co 2+ and Ni 2+ dopants were selected as the most favorable candidates, on the basis of their documented spectral properties in the scientific literature. Thus far, the authors have characterized the absorption and emission properties of these ions in the ZnS and ZnSe crystals. The absorption spectra are used to determine the preferred wavelength at which the crystal should be pumped, while the emission spectra reveal the extent of the tuning range potentially offered by the material. In addition, measurements of the emission lifetime as a function of temperature turn out to be quite useful, since this data is suggestive of the room temperature emission yield

Tuning direct bandgap GeSn/Ge quantum dots' interband and intraband useful emission wavelength: Towards CMOS compatible infrared optical devices

Science.gov (United States)

Baira, Mourad; Salem, Bassem; Madhar, Niyaz Ahamad; Ilahi, Bouraoui

2018-05-01

In this work, interband and intraband optical transitions from direct bandgap strained GeSn/Ge quantum dots are numerically tuned by evaluating the confined energies for heavy holes and electrons in D- and L-valley. The practically exploitable emission wavelength ranges for efficient use in light emission and sensing should fulfill specific criteria imposing the electrons confined states in D-valley to be sufficiently below those in L-valley. This study shows that GeSn quantum dots offer promising opportunity towards high efficient group IV based infrared optical devices operating in the mid-IR and far-IR wavelength regions.

Microsecond pulsed optical parametric oscillator pumped by a Q-switched fiber laser

NARCIS (Netherlands)

Klein, M.E.; Adel, P.; Auerbach, M.; Fallnich, C.; Gross, P.; Boller, Klaus J.

2003-01-01

We report on what is to our knowledge the first optical parametric oscillator (OPO) pumped by microsecond pulses from a wavelength-tunable solid-state laser. The singly resonant OPO (SRO) is based on a periodically poled LiNbO3 crystal and pumped with 2.1-ms-long pulses from an actively Q-switched

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.

Intersubband Rabi oscillations in asymmetric nanoheterostructures: implications for a tunable continuous-wave source of a far-infrared and THz radiation.

Science.gov (United States)

Kukushkin, V A

2012-06-01

A tunable continuous-wave source of a far-infrared and THz radiation based on a semiconductor nanoheterostructure with asymmetric quantum wells is suggested. It utilizes Rabi oscillations at a transition between quantum well subbands excited by external femtosecond pulses of a mid-infrared electromagnetic field. Due to quantum well broken inversion symmetry the subbands possess different average dipole moments, which enables the creation of polarization at the Rabi frequency as the subband populations change. It is shown that if this polarization is excited so that it is periodic in space, then, though being pulsed, it can produce continuous-wave output radiation. Changing the polarization space period and the time intervals between the exciting pulses, one can tune the frequency of this radiation throughout the far-infrared and THz range. In the present work a concrete multiple quantum well heterostructure design and a scheme of its space-periodic polarization are suggested. It is shown that for existing sources of mid-infrared femtosecond pulses the proposed scheme can provide a continuous-wave output power of order the power of far-infrared and THz quantum cascade lasers. Being added to the possibility of its output frequency tuning, this can make the suggested device attractive for fundamental research and various applications.

THE FAR-INFRARED SPECTROSCOPY OF VERY LARGE NEUTRAL POLYCYCLIC AROMATIC HYDROCARBONS

International Nuclear Information System (INIS)

Ricca, Alessandra; Bauschlicher, Charles W.; Mattioda, Andrew L.; Boersma, Christiaan; Allamandola, Louis J.

2010-01-01

Here we report the computed far-infrared (FIR) spectra of neutral polycyclic aromatic hydrocarbon (PAH) molecules containing at least 82 carbons up to 130 carbons and with shapes going from compact round and oval-type structures to rectangular and to trapezoidal. The effects of size and shape on the FIR band positions and intensities are discussed. Using FIR data from the NASA Ames PAH IR Spectroscopic Database Version 1.1, we generate synthetic spectra that support the suggestion that the 16.4, 17.4, and 17.8 μm bands arise from PAHs.

Self-pumped optical phase conjugation and light oscillation in Fe doped KNbO 3

Science.gov (United States)

Medrano, C.; Ingold, M.; Günter, P.

1990-07-01

We report different experiments on self-pumped phase conjugation in iron doped KNbO 3 crystals at room temperature. Self-pumped phase conjugate reflectivities of a linear cavity, an external ring mirror and a configuration where no external optical elements are required have been measured. Using the passive ring resonator a reflectivity of 30% of a self-pumped phase conjugate mirror has been measured at room temperature. In the configuration requiring no external optical elements besides the KNbO 3 crystal a reflectivity of 12% has been measured. In degenerate four-wave mixing phase conjugate reflectivities of up to 270% have been observed in the diffusion recording mode.

Downwelling Far-Infrared Radiance Spectra Measured by FIRST at Cerro Toco, Chile

Science.gov (United States)

Mast, J. C.; Mlynczak, M. G.; Cageao, R.; Kratz, D. P.; Latvakoski, H.; Johnson, D. G.; Mlawer, E. J.; Turner, D. D.

2015-12-01

The Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument is a Fourier transform spectrometer developed by NASA Langley Research Center in collaboration with the Space Dynamics Laboratory and the Harvard-Smithsonian Center for Astrophysics. FIRST was initially developed for measuring the far-infrared portion of Earth's longwave spectrum as a balloon borne instrument and later was reconfigured to operate as a ground-based instrument. In its current ground-based configuration FIRST was deployed at 17500 ft on Cerro Toco, a mountain in the Atacama Desert of Chile, from August to October, 2009. There the integrated precipitable water (IPW) was as low as 0.02 cm. FIRST measurements from days with IPW between 0.024 and 0.035 cm during the campaign are presented here between 200 cm-1 and 800 cm-1. Significant spectral development in the far-IR is observed over the entire 200 cm-1 to 800 cm-1 band. Water vapor and temperature profiles from radiosonde and GVRP measurements are used as inputs to the AER Line-by-Line Radiative Transfer Model (LBLRTM) utilizing the AER v3.2 line parameter database. Uncertainties in both the measured and modeled radiances are accounted for in this study. The residual LBLRTM - FIRST is calculated to assess agreement between the measured and modeled spectra. Measured and model radiances generally agree to within the combined uncertainties for wavenumbers greater than 360 cm-1. At wavenumbers less than 360 cm-1 persistent troughs in the residual are present outside of the combined uncertainties. These features are present on different days and at different water vapor amounts. Possible solutions for these features are discussed.

Far infrared and terahertz spectroscopy of ferroelectric soft modes in thin films: a review

Czech Academy of Sciences Publication Activity Database

Petzelt, Jan; Kamba, Stanislav

2016-01-01

Roč. 503, č. 1 (2016), s. 19-44 ISSN 0015-0193 R&D Projects: GA ČR GA15-08389S Institutional support: RVO:68378271 Keywords : soft mode * central mode * ferroelectric thin film * terahertz spectroscopy * far-infrared spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.551, year: 2016

Determination of carbohydrates in Folium Lysium Chinensis using capillary electrophoresis combined with far-infrared light irradiation-assisted extraction.

Science.gov (United States)

Fu, Yuejiao; Zhang, Luyan; Chen, Gang

2011-11-01

In this work, a method based on capillary electrophoresis with amperometric detection and far-infrared-assisted extraction has been developed for the determination of mannitol, sucrose, glucose and fructose in Folium Lysium Chinensis, a commonly used traditional Chinese medicine. The water-soluble constituents in the herbal drug were extracted with double distilled water with the assistance of far-infrared radiations. The effects of detection potential, irradiation time, and the voltage applied on the infrared generator were investigated to acquire the optimum analysis conditions. The detection electrode was a 300-μm-diameter copper disk electrode at a detection potential of +0.65 V. The four carbohydrates could be well separated within 18 min in a 50-cm length fused-silica capillary at a separation voltage of 9 kV in a 50-mM NaOH aqueous solution. The relation between peak current and analyte concentration was linear over about three orders of magnitude with detection limits (S/N=3) ranging from 0.66 to 1.15 μM for all analytes. The results indicated that far infrared significantly enhanced the extraction efficiency of the carbohydrates in Folium Lysium Chinensis. The extraction time was significantly reduced to 7 min compared with several hours for conventional hot solvent extraction. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High resolution far-infrared observations of the evolved H II region M16

International Nuclear Information System (INIS)

McBreen, B.; Fazio, G.G.; Jaffe, D.T.

1982-01-01

M16 is an evolved, extremely density bounded H II region, which now consists only of a series of ionization fronts at molecular cloud boundaries. The source of ionization is the OB star cluster (NGC 6611) which is about 5 x 10 6 years old. We used the CFA/UA 102 cm balloon-borne telescope to map this region and detected three far-infrared (far-IR) sources embedded in an extended ridge of emission. Source I is an unresolved far-IR source embedded in a molecular cloud near a sharp ionization front. An H 2 O maser is associated with this source, but no radio continuum emission has been observed. The other two far-IR sources (II and III) are associated with ionized gas-molecular cloud interfaces, with the far-IR radiation arising from dust at the boundary heated by the OB cluster. Source II is located at the southern prominent neutral intrusion with its associated bright rims and dark ''elephant trunk'' globules that delineate the current progress of the ionization front into the neutral material, and Source III arises at the interface of the northern molecular cloud fragment

Optically controlled tunable dispersion compensators based on pumped fiber gratings.

Science.gov (United States)

Shu, Xuewen; Sugden, Kate; Bennion, Ian

2011-08-01

We demonstrate optically tunable dispersion compensators based on pumping fiber Bragg gratings made in Er/Yb codoped fiber. The tunable dispersion for a chirped grating and also a uniform-period grating was successfully demonstrated in the experiment. The dispersion of the chirped grating was tuned from 900 to 1990 ps/nm and also from -600 to -950 ps/nm in the experiment. © 2011 Optical Society of America

Added Value of Far-Infrared Radiometry for Ice Cloud Remote Sensing

Science.gov (United States)

Libois, Q.; Blanchet, J. P.; Ivanescu, L.; S Pelletier, L.; Laurence, C.

2017-12-01

Several cloud retrieval algorithms based on satellite observations in the infrared have been developed in the last decades. However, most of these observations only cover the midinfrared (MIR, λ technology, though, now make it possible to consider spaceborne remote sensing in the FIR. Here we show that adding a few FIR channels with realistic radiometric performances to existing spaceborne narrowband radiometers would significantly improve their ability to retrieve ice cloud radiative properties. For clouds encountered in the polar regions and the upper troposphere, where the atmosphere above clouds is sufficiently transparent in the FIR, using FIR channels would reduce by more than 50% the uncertainties on retrieved values of optical thickness, effective particle diameter, and cloud top altitude. This would somehow extend the range of applicability of current infrared retrieval methods to the polar regions and to clouds with large optical thickness, where MIR algorithms perform poorly. The high performance of solar reflection-based algorithms would thus be reached in nighttime conditions. Using FIR observations is a promising venue for studying ice cloud microphysics and precipitation processes, which is highly relevant for cirrus clouds and convective towers, and for investigating the water cycle in the driest regions of the atmosphere.

Application of far-infrared spectroscopy to the structural identification of protein materials.

Science.gov (United States)

Han, Yanchen; Ling, Shengjie; Qi, Zeming; Shao, Zhengzhong; Chen, Xin

2018-05-03

Although far-infrared (IR) spectroscopy has been shown to be a powerful tool to determine peptide structure and to detect structural transitions in peptides, it has been overlooked in the characterization of proteins. Herein, we used far-IR spectroscopy to monitor the structure of four abundant non-bioactive proteins, namely, soybean protein isolate (SPI), pea protein isolate (PPI) and two types of silk fibroins (SFs), domestic Bombyx mori and wild Antheraea pernyi. The two globular proteins SPI and PPI result in broad and weak far-IR bands (between 50 and 700 cm-1), in agreement with those of some other bioactive globular proteins previously studied (lysozyme, myoglobin, hemoglobin, etc.) that generally only have random amino acid sequences. Interestingly, the two SFs, which are characterized by a structure composed of highly repetitive motifs, show several sharp far-IR characteristic absorption peaks. Moreover, some of these characteristic peaks (such as the peaks at 260 and 428 cm-1 in B. mori, and the peaks at 245 and 448 cm-1 in A. pernyi) are sensitive to conformational changes; hence, they can be directly used to monitor conformational transitions in SFs. Furthermore, since SF absorption bands clearly differ from those of globular proteins and different SFs even show distinct adsorption bands, far-IR spectroscopy can be applied to distinguish and determine the specific SF component within protein blends.

Third harmonic generation of high power far infrared radiation in semiconductors

Energy Technology Data Exchange (ETDEWEB)

Urban, M [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

1996-04-01

We investigated the third harmonic generation of high power infrared radiation in doped semiconductors with emphasis on the conversion efficiency. The third harmonic generation effect is based on the nonlinear response of the conduction band electrons in the semiconductor with respect to the electric field of the incident electromagnetic wave. Because this work is directed towards a proposed application in fusion plasma diagnostics, the experimental requirements for the radiation source at the fundamental frequency are roughly given as follows: a wavelength of the radiation at the fundamental frequency in the order of 1 mm and an incident power greater than 1 MW. The most important experiments of this work were performed using the high power far infrared laser of the CRPP. With this laser a new laser line was discovered, which fits exactly the source specifications given above: the wavelength is 676 {mu}m and the maximum power is up to 2 MW. Additional experiments were carried out using a 496 {mu}m laser and a 140 GHz (2.1 mm) gyrotron. The main experimental progress with respect to previous work in this field is, in addition to the use of a very high power laser, the possibility of an absolute calibration of the detectors for the far infrared radiation and the availability of a new type of detector with a very fast response. This detector made it possible to measure the power at the fundamental as well as the third harmonic frequency with full temporal resolution of the fluctuations during the laser pulse. Therefore the power dependence of the third harmonic generation efficiency could be measured directly. The materials investigated were InSb as an example of a narrow gap semiconductor and Si as standard material. The main results are: narrow gap semiconductors indeed have a highly nonlinear electronic response, but the narrow band gap leads at the same time to a low power threshold for internal breakdown, which is due to impact ionization. figs., tabs., refs.

Third harmonic generation of high power far infrared radiation in semiconductors

International Nuclear Information System (INIS)

Urban, M.

1996-04-01

In this work we investigated the third harmonic generation of high power infrared radiation in doped semiconductors with emphasis on the conversion efficiency. The third harmonic generation effect is based on the nonlinear response of the conduction band electrons in the semiconductor with respect to the electric field of the incident electromagnetic wave. Because this work is directed towards a proposed application in fusion plasma diagnostics, the experimental requirements for the radiation source at the fundamental frequency are roughly given as follows: a wavelength of the radiation at the fundamental frequency in the order of 1 mm and an incident power greater than 1 MW. The most important experiments of this work were performed using the high power far infrared laser of the CRPP. With this laser a new laser line was discovered, which fits exactly the source specifications given above: the wavelength is 676 μm and the maximum power is up to 2 MW. Additional experiments were carried out using a 496 μm laser and a 140 GHz (2.1 mm) gyrotron. The main experimental progress with respect to previous work in this field is, in addition to the use of a very high power laser, the possibility of an absolute calibration of the detectors for the far infrared radiation and the availability of a new type of detector with a very fast response. This detector made it possible to measure the power at the fundamental as well as the third harmonic frequency with full temporal resolution of the fluctuations during the laser pulse. Therefore the power dependence of the third harmonic generation efficiency could be measured directly. The materials investigated were InSb as an example of a narrow gap semiconductor and Si as standard material. The main results are: narrow gap semiconductors indeed have a highly nonlinear electronic response, but the narrow band gap leads at the same time to a low power threshold for internal breakdown, which is due to impact ionization. (author) figs

Numerical analysis of intrinsic bistability and chromatic switching in Tm3+ single-doped systems under photon avalanche pumping scheme

International Nuclear Information System (INIS)

Li Li; Zhang Xinlu; Chen Lixue

2008-01-01

In this paper, we predict and numerically demonstrate the intrinsic intensity bistability, spectra bistability and chromatic switching of visible-infrared emission in Tm 3+ single-doped systems that are pumped by the photon avalanche scheme at 648 nm. Based on the coupled rate equation theory, the evolutions of the populations at various Tm 3+ energy levels, emission spectra and fluorescence intensity versus pump excitation are numerically investigated in detail. The results show that intrinsic optical bistability (IOB) associated with emission spectra and luminescence intensity takes place in the vicinity of the avalanche threshold (∼10 kW cm -2 ). When the pump excitation rises above the switching threshold (∼17.5 kW cm -2 ), the chromatic switching between the infrared (1716 nm) and the visible blue (452/469 nm) spectra can be performed. Moreover, the influences of system parameters on IOB and the origin of chromatic switching are discussed. These unique characteristics of Tm 3+ -doped systems would lead to the new possibility of the development of pump-controlled all-solid-state luminescence switches and optical bistability switches.

Far infrared study of molecular reorientations in some alkoxyazoxybenzenes

International Nuclear Information System (INIS)

Godlewska, M.; Kocot, A.

1986-05-01

Far infrared spectra in the frequency range 20 - 200 cm -1 for di-n-alkoxyazoxybenzene homologous series are presented for the isotropic and nematic phases and for 0.1 M solution in benzene. Additionally some partly deuterated samples were measured. The spectra generally consist of two broad bands. By comparison of the spectra for differently deuterated compounds it was possible to interpret the higher frequency band as being connected with the intermolecular torsional vibration of the groups. We connect the band at lower frequencies with the Poley absorption of librating molecules. The confined rotator model calculations performed for this band for all compounds studied give the rotational correlation time which happens to be in good agreement with the correlation times as derived from the quasielastic neutron scattering experiments. 12 refs., 7 figs., 3 tabs. (author)

Far-Infrared Spectroscopy of Weakly Bound Hydrated Cluster Molecules

DEFF Research Database (Denmark)

Andersen, Jonas

The thermodynamic properties of condensed phases, the functionality of many materials and the molecular organization in biological organisms are all governed by the classes of non-covalent interactions that occur already on the microscopic scale between pairs of molecules. A detailed investigation...... of the intermolecular interactions between prototypical molecular assemblies are valuable for accurate descriptions of larger supramolecular systems such as materials, gas hydrates and biological macromolecules. The aim of this PhD dissertation is to investigate intermolecular interactions fora series of medium...... vibrational bands of the cluster molecules in the challenging far-infrared and terahertz spectral regions.A key parameter in the validation of the performance of theoretical predictions for weak non-covalent intermolecular interactions is the dissociation energy D0 that depends heavily on the class of large...

Quantum Theory of Conditional Phonon States in a Dual-Pumped Raman Optical Frequency Comb

Science.gov (United States)

Mondloch, Erin

In this work, we theoretically and numerically investigate nonclassical phonon states created in the collective vibration of a Raman medium by the generation of a dual-pumped Raman optical frequency comb in an optical cavity. This frequency comb is generated by cascaded Raman scattering driven by two phase-locked pump lasers that are separated in frequency by three times the Raman phonon frequency. We characterize the variety of conditioned phonon states that are created when the number of photons in all optical frequency modes except the pump modes are measured. Almost all of these conditioned phonon states are extremely well approximated as three-phonon-squeezed states or Schrodinger-cat states, depending on the outcomes of the photon number measurements. We show how the combinations of first-, second-, and third-order Raman scattering that correspond to each set of measured photon numbers determine the fidelity of the conditioned phonon state with model three-phonon-squeezed states and Schrodinger-cat states. All of the conditioned phonon states demonstrate preferential growth of the phonon mode along three directions in phase space. That is, there are three preferred phase values that the phonon state takes on as a result of Raman scattering. We show that the combination of Raman processes that produces a given set of measured photon numbers always produces phonons in multiples of three. In the quantum number-state representation, these multiples of three are responsible for the threefold phase-space symmetry seen in the conditioned phonon states. With a semiclassical model, we show how this three-phase preference can also be understood in light of phase correlations that are known to spontaneously arise in single-pumped Raman frequency combs. Additionally, our semiclassical model predicts that the optical modes also grow preferentially along three phases, suggesting that the dual-pumped Raman optical frequency comb is partially phase-stabilized.

A high field optical-pumping spin-exchange polarized deuterium source

International Nuclear Information System (INIS)

Coulter, K.P.; Holt, R.J.; Kinney, E.R.; Kowalczyk, R.S.; Poelker, M.; Potterveld, D.H.; Young, L.; Zeidman, B.; Toporkov, D.

1992-01-01

Recent results from a prototype high field optical-pumping spin-exchange polarized deuterium source are presented. Atomic polarization as high as 62% have been observed with an intensity of 6.3 x 10 17 atoms-sec -1 and 65% dissociation fraction

Polarised two-photon excitation of quantum well excitons for manipulation of optically pumped terahertz lasers

Energy Technology Data Exchange (ETDEWEB)

Slavcheva, G., E-mail: gsk23@bath.ac.uk [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Kavokin, A.V., E-mail: A.Kavokin@soton.ac.uk [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Spin Optics Laboratory, St. Petersburg State University, 1, Ulyanovskaya 198504 (Russian Federation)

2014-11-15

Optical pumping of excited exciton states in a semiconductor quantum well embedded in a microcavity is a tool for realisation of ultra-compact terahertz (THz) lasers based on stimulated optical transition between excited (2p) and ground (1s) exciton state. We show that the probability of two-photon absorption by a 2p-exciton is strongly dependent on the polarisation of both pumping photons. Five-fold variation of the threshold power for terahertz lasing by switching from circular to co-linear pumping is predicted. We identify photon polarisation configurations for achieving maximum THz photon generation quantum efficiency.

Wide-field Spatio-Spectral Interferometry: Bringing High Resolution to the Far- Infrared

Science.gov (United States)

Leisawitx, David

Wide-field spatio-spectral interferometry combines spatial and spectral interferometric data to provide integral field spectroscopic information over a wide field of view. This technology breaks through a mission cost barrier that stands in the way of resolving spatially and measuring spectroscopically at far-infrared wavelengths objects that will lead to a deep understanding of planetary system and galaxy formation processes. A space-based far-IR interferometer will combine Spitzer s superb sensitivity with a two order of magnitude gain in angular resolution, and with spectral resolution in the thousands. With the possible exception of detector technology, which is advancing with support from other research programs, the greatest challenge for far-IR interferometry is to demonstrate that the interferometer will actually produce the images and spectra needed to satisfy mission science requirements. With past APRA support, our team has already developed the highly specialized hardware testbed, image projector, computational model, and image construction software required for the proposed effort, and we have access to an ideal test facility.

Optical Activation of Germanium Plasmonic Antennas in the Mid-Infrared

Science.gov (United States)

Fischer, Marco P.; Schmidt, Christian; Sakat, Emilie; Stock, Johannes; Samarelli, Antonio; Frigerio, Jacopo; Ortolani, Michele; Paul, Douglas J.; Isella, Giovanni; Leitenstorfer, Alfred; Biagioni, Paolo; Brida, Daniele

2016-07-01

Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on a silicon substrate. This direct approach activates the plasmonic resonance of the Ge structures and enables their use as optical antennas up to the mid-infrared spectral range. The optical switching lasts for hundreds of picoseconds until charge recombination redshifts the plasma frequency. The full behavior of the structures is modeled by the electrodynamic response established by an electron-hole plasma in a regular array of antennas.

High resolution spectroscopy of six SOCl2 isotopologues from the microwave to the far-infrared

Science.gov (United States)

Martin-Drumel, M. A.; Roucou, A.; Brown, G. G.; Thorwirth, S.; Pirali, O.; Mouret, G.; Hindle, F.; McCarthy, M. C.; Cuisset, A.

2016-02-01

Despite its potential role as an atmospheric pollutant, thionyl chloride, SOCl2, remains poorly characterized in the gas phase. In this study, the pure rotational and ro-vibrational spectra of six isotopologues of this molecule, all detected in natural abundance, have been extensively studied from the cm-wave band to the far-infrared region by means of three complementary techniques: chirped-pulse Fourier transform microwave spectroscopy, sub-millimeter-wave spectroscopy using frequency multiplier chain, and synchrotron-based far-infrared spectroscopy. Owing to the complex line pattern which results from two nuclei with non-zero spins, new, high-level quantum-chemical calculations of the hyperfine structure played a crucial role in the spectroscopic analysis. From the combined experimental and theoretical work, an accurate semi-experimental equilibrium structure (reSE) of SOCl2 has been derived. With the present data, spectroscopy-based methods can now be applied with confidence to detect and monitor this species, either by remote sensing or in situ.

Twisting Anderson pseudospins with light: Quench dynamics in terahertz-pumped BCS superconductors

Science.gov (United States)

Chou, Yang-Zhi; Liao, Yunxiang; Foster, Matthew S.

2017-03-01

We study the preparation (pump) and the detection (probe) of far-from-equilibrium BCS superconductor dynamics in THz pump-probe experiments. In a recent experiment [R. Matsunaga, Y. I. Hamada, K. Makise, Y. Uzawa, H. Terai, Z. Wang, and R. Shimano, Phys. Rev. Lett. 111, 057002 (2013), 10.1103/PhysRevLett.111.057002], an intense monocycle THz pulse with center frequency ω ≃Δ was injected into a superconductor with BCS gap Δ ; the subsequent postpump evolution was detected via the optical conductivity. It was argued that nonlinear coupling of the pump to the Anderson pseudospins of the superconductor induces coherent dynamics of the Higgs (amplitude) mode Δ (t ) . We validate this picture in a two-dimensional BCS model with a combination of exact numerics and the Lax reduction method, and we compute the nonequilibrium phase diagram as a function of the pump intensity. The main effect of the pump is to scramble the orientations of Anderson pseudospins along the Fermi surface by twisting them in the x y plane. We show that more intense pump pulses can induce a far-from-equilibrium phase of gapless superconductivity ("phase I"), originally predicted in the context of interaction quenches in ultracold atoms. We show that the THz pump method can reach phase I at much lower energy densities than an interaction quench, and we demonstrate that Lax reduction (tied to the integrability of the BCS Hamiltonian) provides a general quantitative tool for computing coherent BCS dynamics. We also calculate the Mattis-Bardeen optical conductivity for the nonequilibrium states discussed here.

Effect of nano-sized cerium-zirconium oxide solid solution on far-infrared emission properties of tourmaline powders

Science.gov (United States)

Guo, Bin; Yang, Liqing; Hu, Weijie; Li, Wenlong; Wang, Haojing

2015-10-01

Far-infrared functional nanocomposites were prepared by the co-precipitation method using natural tourmaline (XY3Z6Si6O18(BO3)3V3W, where X is Na+, Ca2+, K+, or vacancy; Y is Mg2+, Fe2+, Mn2+, Al3+, Fe3+, Mn3+, Cr3+, Li+, or Ti4+; Z is Al3+, Mg2+, Cr3+, or V3+; V is O2-, OH-; and W is O2-, OH-, or F-) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample, tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that tourmaline modified with Ce and Zr has a better far-infrared emission property than tourmaline modified with Ce alone. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism for oxygen evolution during the heat process in the two composite materials was systematically studied. The XPS spectra show that Fe3+ ratio inside tourmaline modified with Ce alone can be raised by doping Zr. Moreover, it is showed that there is a higher Ce3+ ratio inside the tourmaline modified with Ce and Zr than tourmaline modified with Ce alone. In addition, XRD results indicate the formation of CeO2 and Ce1-xZrxO2 crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe2+ to Fe3+ inside the tourmaline caused by the change in the catalyst redox properties of CeO2 brought about by doping with Zr4+. In all samples, tourmaline modified with 7.14 wt.% Ce and 1.86 wt.% Zr calcined at 800∘C for 5 h has the best far-infrared emission property with the maximum emissivity value of 98%.

Measured and Modeled Downwelling Far-Infrared Radiances in Very Dry Environments and Calibration Requirements for Future Experiments

Science.gov (United States)

Mast, J. C.; Mlynczak, M. G.; Cageao, R.; Kratz, D. P.; Latvakoski, H.; Johnson, D. G.; Mlawer, E. J.; Turner, D. D.

2016-12-01

Downwelling radiances measured by the Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument in an environment with integrated precipitable water as low as 0.03 cm are compared with calculated spectra in the far-infrared and mid-infrared. In its current ground-based configuration FIRST was deployed to 5.38 km on Cerro Toco, a mountain in the Atacama Desert of Chile, from August to October 2009. There FIRST took part in the Radiative Heating in Unexplored Bands Campaign Part 2. Water vapor and temperature profiles from an optimal-estimation-based physical retrieval algorithm (using simultaneous radiosonde and multichannel 183 GHz microwave radiometer measurements) are input to the AER Line-by-Line Radiative Transfer Model (LBLRTM) to compute radiances for comparison with FIRST. The AER v3.4 line parameter database is used. The low water vapor amounts and relatively cold atmosphere result in extremely small far-IR radiances (1.5 mW/m2/sr/cm-1) with corresponding brightness temperatures of 120 K. The residual LBLRTM minus FIRST is calculated to assess agreement between the measured and modeled spectra. Uncertainties in both the measured and modeled radiances are accounted for in the comparison. A goal of the deployment and subsequent analysis is the assessment of water vapor spectroscopy in the far-infrared and mid-infrared. While agreement is found between measured and modeled radiances within the combined uncertainties across all spectra, uncertainties in the measured water vapor profiles and from the laboratory calibration exceed those associated with water vapor spectroscopy in this very low radiance environment. Consequently, no improvement in water vapor spectroscopy is afforded by these measurements. However, we use these results to place requirements on instrument calibration accuracy and water vapor profile accuracy for future campaigns to similarly dry environments. Instrument calibration uncertainty needs to be at 2% (1-sigma) of measured radiance

Comparison of stellar population model predictions using optical and infrared spectroscopy

Science.gov (United States)

Baldwin, C.; McDermid, R. M.; Kuntschner, H.; Maraston, C.; Conroy, C.

2018-02-01

We present Gemini/GNIRS cross-dispersed near-infrared spectra of 12 nearby early-type galaxies, with the aim of testing commonly used stellar population synthesis models. We select a subset of galaxies from the ATLAS3D sample which span a wide range of ages (single stellar population equivalent ages of 1-15 Gyr) at approximately solar metallicity. We derive star formation histories using four different stellar population synthesis models, namely those of Bruzual & Charlot, Conroy, Gunn & White, Maraston & Strömbäck and Vazdekis et al. We compare star formation histories derived from near-infrared spectra with those derived from optical spectra using the same models. We find that while all models agree in the optical, the derived star formation histories vary dramatically from model to model in the near-infrared. We find that this variation is largely driven by the choice of stellar spectral library, such that models including high-quality spectral libraries provide the best fits to the data, and are the most self-consistent when comparing optically derived properties with near-infrared ones. We also find the impact of age variation in the near-infrared to be subtle, and largely encoded in the shape of the continuum, meaning that the common approach of removing continuum information with a high-order polynomial greatly reduces our ability to constrain ages in the near-infrared.

Hollow Core Optical Fiber Gas Lasers: Toward Novel and Practical Systems in Fused Silica

Science.gov (United States)

2017-05-18

Hollow core Optically pumped Fiber Gas LASer’s (HOFGLAS’s) based on population inversion combine advantages of fiber lasers such as long interaction...polarization dependent fiber properties. Preliminary experiments were performed toward simultaneous lasing in the visible and near infrared; lasing in...words) Hollow core Optically pumped Fiber Gas LASer’s (HOFGLAS’s) based on population inversion combine advantages of fiber lasers such as long

A hybrid type undulator for far-infrared FELs at FELI

Energy Technology Data Exchange (ETDEWEB)

Zako, A.; Miyauchi, Y.; Koga, A. [Free Electron Laser Research Institute, Inc., Osaka (Japan)] [and others

1995-12-31

Two FEL facilities of the FELI are now operating in the wavelength range of 1-20 {mu}m. A 3.2-m hybrid type undulator ({lambda}{sub u}=80mm, N=40) has been designed for far-infrared FELs and will be installed in December. It can cover the wavelength of 20-60 {mu}m by changing K-value from 1 to 2.7 for a 28.0-MeV electron beam. It is composed of ferrite magnetic poles and Sm-Co permanent magnets. Commonly wound coils induce alternating magnetic field in ferrite poles. Combination of the induced field and the permanent magnet field can controls the magnetic field between the undulator gap.

Experimental test of far-infrared polarimetry for Faraday rotation measurements on the TFR 600 Tokamak

Energy Technology Data Exchange (ETDEWEB)

Soltwisch, H [Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.). Inst. fuer Plasmaphysik; Association Euratom-Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.)); Equipe, T F.R. [Association Euratom-CEA sur la Fusion, Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France). Dept. de Recherches sur la Fusion Controlee

1981-09-01

The results are reported on the feasibility of using far-infrared polarimetry for Faraday rotation diagnostic measurements on the TRF Tokamak. Precise quantitative results were not obtained but a satisfactory agreement with a simple theoretical model leads to a good understanding of the experimental limitations of the method.

Second-harmonic scanning optical microscopy of semiconductor quantum dots

DEFF Research Database (Denmark)

Vohnsen, B.; Bozhevolnyi, S.I.; Pedersen, K.

2001-01-01

Second-harmonic (SH) optical imaging of self-assembled InAlGaAs quantum dots (QD's) grown on a GaAs(0 0 1) substrate has been accomplished at room temperature by use of respectively a scanning far-field optical microscope in reflection mode and a scanning near-field optical microscope...... in transmission mode. In both cases the SH signal peaks at a pump wavelength of similar to 885 nm in correspondence to the maximum in the photoluminescence spectrum of the QD sample. SH near-field optical images exhibit spatial signal variations on a subwavelength scale that depend on the pump wavelength. We...

Optical Pumping Spin Exchange 3He Gas Cells for Magnetic Resonance Imaging

Science.gov (United States)

Kim, W.; Stepanyan, S. S.; Kim, A.; Jung, Y.; Woo, S.; Yurov, M.; Jang, J.

2009-08-01

We present a device for spin-exchange optical pumping system to produce large quantities of polarized noble gases for Magnetic Resonance Imaging (MRI). A method and design of apparatus for pumping the polarization of noble gases is described. The method and apparatus enable production, storage and usage of hyperpolarized noble gases for different purposes, including Magnetic Resonance Imaging of human and animal subjects. Magnetic imaging agents breathed into lungs can be observed by the radio waves of the MRI scanner and report back physical and functional information about lung's health and desease. The technique known as spin exchange optical pumping is used. Nuclear magnetic resonance is implemented to measure the polarization of hyperpolarized gas. The cells prepared and sealed under high vacuum after handling Alkali metals into the cell and filling with the 3He-N2 mixture. The cells could be refilled. The 3He reaches around 50% polarization in 5-15 hours.

Intracavity Cr3+:LiCAF + PPSLT optical parametric oscillator with self-injection-locked pump wave

International Nuclear Information System (INIS)

Maestre, H; Torregrosa, A J; Capmany, J

2013-01-01

In this letter we present an intracavity pumped continuous wave (CW) doubly resonant optical parametric oscillator (OPO) based on Cr 3+ :LiCaAlF 6 (Cr:LiCAF) as the material generating the OPO pump wave and periodically poled stoichiometric lithium tantalate (PPSLT) as the nonlinear material. The OPO pump wave is spectrally narrowed and tuned by means of an external cavity, thus allowing self-injection locking of the OPO pump wavelength. When operated near degeneracy, the constructed OPO enables a fast tuning of the parametrically generated wavelengths in response to small perturbations of the phase-matching condition. The Cr:LiCAF emission band is especially well suited to provide dual-wavelength oscillation in the optical communications 1550 nm band as a result of the parametric oscillation in PPSLT. (letter)

Hierarchical Models for Type Ia Supernova Light Curves in the Optical and Near Infrared

Science.gov (United States)

Mandel, Kaisey; Narayan, G.; Kirshner, R. P.

2011-01-01

I have constructed a comprehensive statistical model for Type Ia supernova optical and near infrared light curves. Since the near infrared light curves are excellent standard candles and are less sensitive to dust extinction and reddening, the combination of near infrared and optical data better constrains the host galaxy extinction and improves the precision of distance predictions to SN Ia. A hierarchical probabilistic model coherently accounts for multiple random and uncertain effects, including photometric error, intrinsic supernova light curve variations and correlations across phase and wavelength, dust extinction and reddening, peculiar velocity dispersion and distances. An improved BayeSN MCMC code is implemented for computing probabilistic inferences for individual supernovae and the SN Ia and host galaxy dust populations. I use this hierarchical model to analyze nearby Type Ia supernovae with optical and near infared data from the PAIRITEL, CfA3, and CSP samples and the literature. Using cross-validation to test the robustness of the model predictions, I find that the rms Hubble diagram scatter of predicted distance moduli is 0.11 mag for SN with optical and near infrared data versus 0.15 mag for SN with only optical data. Accounting for the dispersion expected from random peculiar velocities, the rms intrinsic prediction error is 0.08-0.10 mag for SN with both optical and near infrared light curves. I discuss results for the inferred intrinsic correlation structures of the optical-NIR SN Ia light curves and the host galaxy dust distribution captured by the hierarchical model. The continued observation and analysis of Type Ia SN in the optical and near infrared is important for improving their utility as precise and accurate cosmological distance indicators.

77 FR 36579 - II-VI, Inc., Infrared Optics-Saxonburg Division, Saxonburg, PA; Leased Workers From Adecco, Carol...

Science.gov (United States)

2012-06-19

...., Infrared Optics-Saxonburg Division, Saxonburg, PA; Leased Workers From Adecco, Carol Harris, Unlimited Staffing, and Staffmark, Working On-Site at II-VI, Inc., Infrared Optics-Saxonburg Division, Saxonburg, PA... workers and former workers of II-VI, Inc., Infrared Optics-Saxonburg Division, Saxonburg, Pennsylvania...

Analysis of the selected optical parameters of filters protecting against hazardous infrared radiation

OpenAIRE

Gralewicz, Grzegorz; Owczarek, Grzegorz

2016-01-01

The paper analyses the selected optical parameters of protective optic filters used for protection of the eyes against hazardous radiation within the visible (VIS) and near infrared (NIR) spectrum range. The indexes characterizing transmission and reflection of optic radiation incident on the filter are compared. As it follows from the completed analysis, the newly developed interference filters provide more effective blocking of infrared radiation in comparison with the currently used protec...

Characterization methods of integrated optics for mid-infrared interferometry

Science.gov (United States)

Labadie, Lucas; Kern, Pierre Y.; Schanen-Duport, Isabelle; Broquin, Jean-Emmanuel

2004-10-01

his article deals with one of the important instrumentation challenges of the stellar interferometry mission IRSI-Darwin of the European Space Agency: the necessity to have a reliable and performant system for beam combination has enlightened the advantages of an integrated optics solution, which is already in use for ground-base interferometry in the near infrared. Integrated optics provides also interesting features in terms of filtering, which is a main issue for the deep null to be reached by Darwin. However, Darwin will operate in the mid infrared range from 4 microns to 20 microns where no integrated optics functions are available on-the-shelf. This requires extending the integrated optics concept and the undergoing technology in this spectral range. This work has started with the IODA project (Integrated Optics for Darwin) under ESA contract and aims to provide a first component for interferometry. In this paper are presented the guidelines of the characterization work that is implemented to test and validate the performances of a component at each step of the development phase. We present also an example of characterization experiment used within the frame of this work, is theoretical approach and some results.

Packaging of high-power bars for optical pumping and direct applications

Science.gov (United States)

Heinemann, Stefan; An, Haiyan; Barnowski, Tobias; Jiang, John; Negoita, Viorel; Roff, Robert; Vethake, Thilo; Boucke, Konstantin; Treusch, Georg

2015-03-01

Continuous cost reduction, improved reliability and modular platform guide the design of our next generation heatsink and packaging process. Power scaling from a single device effectively lowers the cost, while electrical insulation of the heatsink, low junction temperature and hard solder enable high reliability. We report on the latest results for scaling the output power of bars for optical pumping and materials processing. The epitaxial design and geometric structures are specific for the application, while packaging with minimum thermal impedance, low stress and low smile are generic features. The isolated heatsink shows a thermal impedance of 0.2 K/W and the maximum output power is limited by the requirement of a junction temperature of less than 68oC for high reliability. Low contact impedance are addressed for drive currents of 300 A. For pumping applications, bars with a fill factor of 60% are deployed emitting more than 300 W of output power with an efficiency of about 55% and 8 bars are arranged in a compact pump module emitting 2 kW of collimated power suitable for pumping disk lasers. For direct applications we target coupling kilowatts of output powers into fibers of 100 μm diameter with 0.1 NA based on dense wavelength multiplexing. Low fill factor bars with large optical waveguide and specialized coating also emit 300 W.

THE ORIGIN OF THE INFRARED EMISSION IN RADIO GALAXIES. II. ANALYSIS OF MID- TO FAR-INFRARED SPITZER OBSERVATIONS OF THE 2JY SAMPLE

NARCIS (Netherlands)

Dicken, D.; Tadhunter, C.; Axon, D.; Morganti, R.; Inskip, K. J.; Holt, J.; Delgado, R. Gonzalez; Groves, B.

2009-01-01

We present an analysis of deep mid- to far-infrared (MFIR) Spitzer photometric observations of the southern 2Jy sample of powerful radio sources (0.05

MID- AND FAR-INFRARED PROPERTIES OF A COMPLETE SAMPLE OF LOCAL ACTIVE GALACTIC NUCLEI

International Nuclear Information System (INIS)

Ichikawa, Kohei; Ueda, Yoshihiro; Terashima, Yuichi; Oyabu, Shinki; Gandhi, Poshak; Nakagawa, Takao; Matsuta, Keiko

2012-01-01

We investigate the mid- (MIR) to far-infrared (FIR) properties of a nearly complete sample of local active galactic nuclei (AGNs) detected in the Swift/Burst Alert Telescope (BAT) all-sky hard X-ray (14-195 keV) survey, based on the cross correlation with the AKARI infrared survey catalogs complemented by those with Infrared Astronomical Satellite and Wide-field Infrared Survey Explorer. Out of 135 non-blazer AGNs in the Swift/BAT nine-month catalog, we obtain the MIR photometric data for 128 sources either in the 9, 12, 18, 22, and/or 25 μm band. We find good correlation between their hard X-ray and MIR luminosities over three orders of magnitude (42 λ (9, 18 μm) < 45), which is tighter than that with the FIR luminosities at 90 μm. This suggests that thermal emission from hot dusts irradiated by the AGN emission dominate the MIR fluxes. Both X-ray unabsorbed and absorbed AGNs follow the same correlation, implying isotropic infrared emission, as expected in clumpy dust tori rather than homogeneous ones. We find excess signals around 9 μm in the averaged infrared spectral energy distribution from heavy obscured 'new type' AGNs with small scattering fractions in the X-ray spectra. This could be attributed to the polycyclic aromatic hydrocarbon emission feature, suggesting that their host galaxies have strong starburst activities.

Ultrafast supercontinuum fiber-laser based pump-probe scanning magneto-optical Kerr effect microscope for the investigation of electron spin dynamics in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution.

Science.gov (United States)

Henn, T; Kiessling, T; Ossau, W; Molenkamp, L W; Biermann, K; Santos, P V

2013-12-01

We describe a two-color pump-probe scanning magneto-optical Kerr effect microscope which we have developed to investigate electron spin phenomena in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution. The key innovation of our microscope is the usage of an ultrafast "white light" supercontinuum fiber-laser source which provides access to the whole visible and near-infrared spectral range. Our Kerr microscope allows for the independent selection of the excitation and detection energy while avoiding the necessity to synchronize the pulse trains of two separate picosecond laser systems. The ability to independently tune the pump and probe wavelength enables the investigation of the influence of excitation energy on the optically induced electron spin dynamics in semiconductors. We demonstrate picosecond real-space imaging of the diffusive expansion of optically excited electron spin packets in a (110) GaAs quantum well sample to illustrate the capabilities of the instrument.

Direction of Wolf-Rayet stars in a very powerful far-infrared galaxy - Direct evidence for a starburst

International Nuclear Information System (INIS)

Armus, L.; Heckman, T.M.; Miley, G.K.

1988-01-01

Spectra covering the wavelength range 4476-7610 A are presented for the powerful far-infrared galaxy IRAS 01003-2238. The broad emission band centered at a rest wavelength of roughly 4660 A, and other broad weaker features are interpreted, as arising from the combined effect of approximately 100,000 late Wolf-Rayet stars of the WN subtype. This represents perhaps the most direct evidence to date for the presence of a large number of hot massive stars in the nucleus of a very powerful far-infrared galaxy. The high number of Wolf-Rayet stars in relation to the number of O-type stars may be interpreted as arguing against continuous steady state star formation in 01003-2238, in favor of a recent burst of star formation occurring approximately 100 million yrs ago. 24 references

Performance of continuous wave and acousto-optically Q-switched Tm, Ho: YAP laser pumped by diode laser

Science.gov (United States)

Li, Guoxing; Xie, Wenqiang; Yang, Xining; Zhang, Ziqiu; Zhang, Hongda; Zhang, Liang

2018-02-01

A two-end-pumped a-cut Tm(0.5%), Ho(0.5%):YAP laser output at 2119nm is reported under cryogenic temperature. The maximum output power reached to 7.76W with the incident pump power of 24.2W in CW mode. With the acousto-optically Q-switch, an average power of 7.3W can be obtained, when the pulse repetition frequency was 7.5 kHz. The corresponding optical-to-optical conversion efficiency was 30.2% and the slope efficiency was 31.4%. Then, the laser output characteristics in the repetition frequency of 7.5 kHz and 10kHz were researched. The output power, the optical-to-optical conversion efficiency and slope efficiency were increased with the increase of the repetition frequency. In the same repetition frequency, the pulse duration was decreasing with the growth of the incident pump power.

Fourier Transform Infrared spectrum of the OCD bending mode in methanol-D1

Science.gov (United States)

Mukhopadhyay, Indra

2016-03-01

The infrared (IR) spectra corresponding to OCD bending vibration of asymmetrically deuterated methanol species CH2DOH have been recorded with a Fourier Transform Spectrometer. The spectrum shows a typical structure of a parallel a-type band. This is expected because the bending vibration mainly executed parallel to the symmetry axis The Q-branch lines are grouped closely around 896 cm-1 and the P- and R-Branches show complex structure. Nonetheless it was possible to assign a-type P- and R-branch lines up to K value of 8 and J value up to about 20 in most cases. The Q-branch lines for higher K values can be followed to about J = 15, the presence of which confirmed the assignments. The observations suggest that in the OCD bend some energy levels are highly interacted by highly excited torsional state from the ground torsional state. A full catalogue is presented along with the effective molecular parameters. An intensity anomaly was also observed in the transitions. So far it has been possible to assign only transitions between e0 ← e0 states. Plausible explanations of intensity anomaly are presented. Lastly, a number of optically pumped far infrared (FIR) laser lines have been assigned either to exact or tentative quantum states. These assignments should prove valuable for production of new FIR laser lines.

Utilization of Infrared Fiber Optic in the Automotive Industry

Science.gov (United States)

Tucker, Dennis S.; Brantley, Lott W. (Technical Monitor)

2001-01-01

Fiber optics are finding a place in the automotive industry. Illumination is the primary application today. Soon, however, fiber optics will be used for data communications and sensing applications. Silica fiber optics and plastic fibers are sufficient for illumination and communication applications however, sensing applications involving high temperature measurement and remote gas analysis would benefit from the use of infrared fiber optics. Chalcogonide and heavy metal fluoride glass optical fibers are two good candidates for these applications. Heavy metal fluoride optical fibers are being investigated by NASA for applications requiring transmission in the infrared portion of the electromagnetic spectrum. Zirconium-Barium-Lanthanum-Aluminum-Sodium-Fluoride (ZBLAN) is one such material which has been investigated. This material has a theoretical attenuation coefficient 100 times lower than that of silica and transmits into the mid-IR. However, the measured attenuation coefficient is higher than silica due to impurities and crystallization. Impurities can be taken care of by utilizing cleaner experimental protocol. It has been found that crystallization can be suppressed by processing in reduced gravity. Fibers processed in reduced gravity on the KC135 reduced gravity aircraft were found to be free of crystals while those processed on the ground were found to have crystals. These results will be presented along with plans for producing continuous lengths of ZBLAN optical fiber on board the International Space Station.

Electrowetting Variable Optics for Visible and Infrared Applications

Science.gov (United States)

Watson, Alexander Maxwell

Miniaturized variable optical devices are important for the fields of medical technology, optical communication, and consumer imaging devices. Areas ranging from endoscopy and optogenetics to atomic clocks and imaging all benefit from versatile optical systems. These applications all require precise and rapid control of imaging focal depth and lateral scanning. Electrowetting variable optics is one emergent technology that has the capability to provide focus tuning, beam steering, and even phase modulation in a small and robust package which requires no moving parts. Furthermore, electrowetting based devices there are attractive due to their transmissive nature, polarization insensitivity, low insertion loss, low electrical power requirements, and high optical quality. These features mean that electrowetting adaptive optical components are an attractive solution, compared with MEMS and liquid crystal optical components. Electrowetting is a technique that enables control of the shape of a liquid droplet with applied voltage. A conductive droplet on a dielectric surface alters its contact angle due to charges that build up between an underlying electrode and the surface of the droplet. This effect can be used to tune the curvature and tilt of liquids within cavities. The liquid boundary creates a high quality surface to use for lensing or steering applications. This thesis will focus on the development of electrowetting based lenses and prisms and applications in imaging for both visible and infrared wavelengths. Within this dissertation is the first demonstration of electrowetting lenses for phase control, as well as the investigation of non-aqueous electrowetting lens liquids for electrowetting lenses operation in the infrared. Key considerations that affect the performance and reliability are dielectric material and thickness, liquid selection and source of ionic conduction. The optical devices presented herein utilize judicious selection of dielectric material

Continuous-wave optically pumped green perovskite vertical-cavity surface-emitter

KAUST Repository

Alias, Mohd Sharizal; Liu, Zhixiong; Alatawi, Abdullah; Ng, Tien Khee; Wu, Tao; Ooi, Boon S.

2017-01-01

We report an optically pumped green perovskite vertical-cavity surface-emitter operating in continuous-wave (CW) with a power density threshold of ~89 kW/cm2. The device has an active region of CH3NH3PbBr3 embedded in a dielectric microcavity

Theoretical considerations and preparatory experiments for poloidal field measurements in tokamaks by far-infrared polarimetry

Energy Technology Data Exchange (ETDEWEB)

Kunz, W; Dodel, G [Stuttgart Univ. (TH) (Germany, F.R.). Inst. fuer Plasmaforschung

1978-12-01

Numerical calculations give an optimum wavelength and show the precision requirements for determining poloidal field profiles in tokamaks on the basis of the Faraday effect. The required precision of the polarimetric measurements can be achieved in the far-infrared as is verified in a model experiment using a ferrite modulated HCN laser beam.

Experimental investigation of saturation effect on pump-to-signal intensity modulation transfer in single-pump phase-insensitive fiber optic parametric amplifiers

DEFF Research Database (Denmark)

Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Lund-Hansen, Toke

2013-01-01

We present an experimental characterization of how signal gain saturation affects the transfer of intensity modulation from the pump to the signal in single-pump, phase-insensitive fiber optic parametric amplifiers (FOPAs). In this work, we demonstrate experimentally for the first time, to our...... knowledge, how gain saturation of a FOPA reduces the noise contribution due to the transfer of pump power fluctuations to the signal. In a particular example, it is shown that the transferred noise is significantly reduced by a factor of 3, while the FOPA gain remains above 10 dB....

Tunable Far Infrared Laser Spectroscopy of Van Der Waals Bonds: Argon-Ammonia

Science.gov (United States)

Gwo, Dz-Hung

Hyperfine resolved vibration-rotation-tunneling spectra of Ar-NH_3 and (NH _3)_2, generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar-NH_3, and the other six belong to (NH_3)_2 . To facilitate the intermolecular vibrational assignment for Ar-NH_3, a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states (K_{a } manifolds). An anomalous vibronically (not just rovibronically) allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar-NH_3 centered at 26.470633(17) cm^{-1} can correlate only to either (1) the fundamental dimeric stretching band for the A_2 states with the NH_3 inversional quantum number v_{i} = 1, or (2) the K_{a} = 0 >=ts 0 subband of the lowest internal-rotation -inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require more far infrared data and a dynamical model incorporating a potential surface.

Analytical studies on pump-induced optical resonances in an M-type six-level system

International Nuclear Information System (INIS)

Ghosh, Saswata; Mandal, Swapan

2010-01-01

In the domain of semiclassical formulation and for the Doppler-free atom-field interaction, we construct the optical Bloch equations involving an M-type six-level system coupled to two pump fields and a probe field. The response of the system is probed for different pump-induced transitions in double and triple-resonance situations. In order to obtain the coherent lineshapes (absorptive and dispersive), we use the usual perturbation method for obtaining the approximate analytical solutions to these coupled optical Bloch equations for the density matrix elements. The interferences between the probability amplitudes for different energy levels (dipole allowed and dipole forbidden) are taken care of. For off-resonance pump positions, the linewidths of the three probe transitions are insensitive to the pump Rabi frequencies. On the other hand, the shifts of the three resonance peaks are extremely sensitive to the pump Rabi frequencies. However, for on-resonance pump conditions, the sensitivities of pump Rabi frequencies on the linewidths of the resonance peaks and on the shifts of the resonance peak positions are opposite to those of their off-resonance counterparts. In particular, we have shown the asymmetric and symmetric Rabi splittings under different physical conditions, for non-zero and near-zero probe detuning, respectively. The Rabi splitting under triple-resonance conditions, significantly, modifies the dispersive lineshape at the centre of the absorption line. The two- and three-photon absorptions are also reported for different off-resonant pump positions.

Mechanical torques generated by optically pumped atomic spin relaxation at surfaces

International Nuclear Information System (INIS)

Herman, R.M.

1982-01-01

It is argued that a valuable method of observing certain types of surface-atom interactions may lie in mechanical torques generated through the spin-orbit relaxation of valence electronic spins of optically pumped atoms at surfaces. The unusual feature of this phenomenon is that the less probable spin-orbit relaxation becomes highly visible as compared with the much more rapid paramagnetic relaxation, because of an enhancement, typically by as much as a factor 10 9 , in the torques delivered to mechanical structures, by virtue of a very large effective moment arm. Spin-orbit relaxation operates through an exchange of translational momentum which, in turn, can be identified with the delivery of a gigantic angular momentum (in units of h) relative to a distant axis about which mechanical motion is referred. The spin-orbit relaxation strongly depends upon the atomic number of the surface atoms and the strength of interaction with the optically pumped atoms. Being dominated by high-atomic-number surface atoms, spin-orbit relaxation rates may not be too strongly influenced by minor surface contamination of lighter-weight optically active atoms

Mechanical torques generated by optically pumped atomic spin relaxation at surfaces

Science.gov (United States)

Herman, R. M.

1982-03-01

It is argued that a valuable method of observing certain types of surface-atom interactions may lie in mechanical torques generated through the spin-orbit relaxation of valence electronic spins of optically pumped atoms at surfaces. The unusual feature of this phenomenon is that the less probable spin-orbit relaxation becomes highly visible as compared with the much more rapid paramagnetic relaxation, because of an enhancement, typically by as much as a factor 109, in the torques delivered to mechanical structures, by virtue of a very large effective moment arm. Spin-orbit relaxation operates through an exchange of translational momentum which, in turn, can be identified with the delivery of a gigantic angular momentum (in units of ℏ) relative to a distant axis about which mechanical motion is referred. The spin-orbit relaxation strongly depends upon the atomic number of the surface atoms and the strength of interaction with the optically pumped atoms. Being dominated by high-atomic-number surface atoms, spin-orbit-relaxation rates may not be too strongly influenced by minor surface contamination of lighter-weight optically active atoms.

Shaping of picosecond pulses for pumping optical parametric amplification

International Nuclear Information System (INIS)

Fueloep, J.A.; Krausz, F.; Major, Zs.; Horvath, B.

2006-01-01

Complete test of publication follows. The use of temporally shaped pump pulses for optical parametric amplification (OPA) is expected to facilitate an increase of efficiency and suppression of possible spectral distortions in this process, since the gain sensitively depends on the pump intensity. Our simulations confirmed such beneficial effect of temporally shaped pump pulses on the OPA process. With the aim to realize an optimized OPA stage pumped by shaped pulses, a novel method for passively shaping narrow band picosecond pulses has been developed. The method is based on the pulse-stacking principle, where replicas of the incoming pulse are created in a specially designed four-beam interferometer. The replicas are recombined with appropriate delays. The interferometer design allows for a unique flexibility in varying the pulse shape, since all relevant degrees of freedom, such as relative intensities and delays between the pulse replicas are independently adjustable. According to our calculations a pulse with a flat-top time profile would provide optimal conditions in the OPA process. Usually the pump pulse needs to be amplified in a conventional laser amplifier prior to the OPA. Our cross-correlation measurements showed that we are able to obtain shaped amplified pulses by shaping the amplifier input. Furthermore, by precompensating the distortions introduced by the amplifier we demonstrated our capability to produce amplified pulses with a flat-top time profile.

Superluminescence from an optically pumped molecular tunneling junction by injection of plasmon induced hot electrons

Directory of Open Access Journals (Sweden)

Kai Braun

2015-05-01

Full Text Available Here, we demonstrate a bias-driven superluminescent point light-source based on an optically pumped molecular junction (gold substrate/self-assembled molecular monolayer/gold tip of a scanning tunneling microscope, operating at ambient conditions and providing almost three orders of magnitude higher electron-to-photon conversion efficiency than electroluminescence induced by inelastic tunneling without optical pumping. A positive, steadily increasing bias voltage induces a step-like rise of the Stokes shifted optical signal emitted from the junction. This emission is strongly attenuated by reversing the applied bias voltage. At high bias voltage, the emission intensity depends non-linearly on the optical pump power. The enhanced emission can be modelled by rate equations taking into account hole injection from the tip (anode into the highest occupied orbital of the closest substrate-bound molecule (lower level and radiative recombination with an electron from above the Fermi level (upper level, hence feeding photons back by stimulated emission resonant with the gap mode. The system reflects many essential features of a superluminescent light emitting diode.

Optically pumped semiconductor lasers for atomic and molecular physics

Science.gov (United States)

Burd, S.; Leibfried, D.; Wilson, A. C.; Wineland, D. J.

2015-03-01

Experiments in atomic, molecular and optical (AMO) physics rely on lasers at many different wavelengths and with varying requirements on spectral linewidth, power and intensity stability. Optically pumped semiconductor lasers (OPSLs), when combined with nonlinear frequency conversion, can potentially replace many of the laser systems currently in use. We are developing a source for laser cooling and spectroscopy of Mg+ ions at 280 nm, based on a frequency quadrupled OPSL with the gain chip fabricated at the ORC at Tampere Univ. of Technology, Finland. This OPSL system could serve as a prototype for many other sources used in atomic and molecular physics.

Far-infrared spectra of polycrystalline Ba2YCu3O/sub 9-//sub δ/

International Nuclear Information System (INIS)

Thomas, G.A.; Ng, H.K.; Millis, A.J.; Bhatt, R.N.; Cava, R.J.; Rietman, E.A.; Johnson, D.W. Jr.; Espinosa, G.P.; Vandenberg, J.M.

1987-01-01

We present far-infrared reflectivity spectra of seven samples of ceramic superconductors in the Ba-Y-Cu-O system with transition temperatures near 93 K. We find superconducting gap structures on the basis of which we estimate the ratio of twice the average gap to the transition temperature to be consistent with 3.5, but possibly higher. Questions of normal-state characterization preclude a definitive analysis

High-temperature Infrared Transmission of Free-standing Diamond Films

Directory of Open Access Journals (Sweden)

HEI Li-fu

2017-02-01

Full Text Available The combination of low absorption and extreme mechanical and thermal properties make diamond a compelling choice for some more extreme far infrared (8-12 μm window applications. The optical properties of CVD diamond at elevated temperatures are critical to many of these extreme applications. The infrared transmission of free-standing diamond films prepared by DC arc plasma jet were studied at temperature varied conditions. The surface morphology, structure feature and infrared optical properties of diamond films were tested by optical microscope, X-ray diffraction, laser Raman and Fourier-transform infrared spectroscopy. The results show that the average transmittance for 8-12μm is decreased from 65.95% at 27℃ to 52.5% at 500℃,and the transmittance drop is in three stages. Corresponding to the drop of transmittance with the temperature, diamond film absorption coefficient increases with the rise of temperature. The influence of the change of surface state of diamond films on the optical properties of diamond films is significantly greater than the influence on the internal structure.

Status of Far Infrared Tangential Interferometry/Polarimetry (FIReTIP) on NSTX

International Nuclear Information System (INIS)

Park, H.K.; Edwards, S.; Guttadora, L.; Deng, B.; Domier, C.W.; Lee, K.C.; Johnson, M.; Luhmann, N.C. Jr.

2000-01-01

The Influence of paramagnetism and diamagnetism will significantly alter the vacuum toroidal magnetic field in the spherical torus. Therefore, plasma parameters dependent upon BT such as the q-profile and the local b value need an independent measurement of BT(r,t). The multi-chord Tangential Far Infrared Interferometer/Polarimeter (FIReTIP) system [1] currently under development for the National Spherical Torus Experiment (NSTX) will provide temporally and radially resolved toroidal field profile [BT(r,t)] and 2-D electron density profile [ne(r,t)] data. A two-channel interferometer will be operational this year and the full system will be ready by 2002

Inhibitory Effects of Far-Infrared Ray-Emitting Belts on Primary Dysmenorrhea

Directory of Open Access Journals (Sweden)

Ben-Yi Liau

2012-01-01

Full Text Available This study investigated the therapeutic effect of the far-infrared ray-emitting belt (FIRB in the management of primary dysmenorrhea in female patients. Forty adolescent females with primary dysmenorrhea were enrolled in the study. Quantitative measurements were taken during the menstruation. Several parameters were measured and compared, including temperature, abdominal blood flow, heart rate variability, and pain assessment. Statistical analysis shows that treatment with FIRB had significant efficiency in increasing regional surface temperature and abdominal blood flow, widening standard deviation of normal-to-normal RR intervals, and reducing VRS and NRS pain scores. The application of an FIRB appears to alleviate dysmenorrhea.

Development of Infrared Phase Closure Capability in the Infrared-Optical Telescope Array (IOTA)

Science.gov (United States)

Traub, Wesley A.

2002-01-01

We completed all major fabrication and testing for the third telescope and phase-closure operation at the Infrared-Optical Telescope Array (IOTA) during this period. In particular we successfully tested the phase-closure operation, using a laboratory light source illuminating the full delay-line optical paths, and using an integrated-optic beam combiner coupled to our Picnic-detector camera. This demonstration is an important and near-final milestone achievement. As of this writing, however, several tasks yet remain, owing to development snags and weather, so the final proof of success, phase-closure observation of a star, is now expected to occur in early 2002, soon after this report has been submitted.

Far Infrared Spectrometry of the Cosmic Background Radiation

Science.gov (United States)

Mather, J. C.

1974-01-01

I describe two experiments to measure the cosmic background radiation near 1 mm wavelength. The first was a ground-based search for spectral lines, made with a Fabry-Perot interferometer and an InSb detector. The second is a measurement of the spectrum from 3 to 18 cm{sup -1}, made with a balloon-borne Fourier transform spectrometer. It is a polarizing Michelson interferometer, cooled in liquid helium, and operated with a germanium bolometer. I give the theory of operation, construction details, and experimental results. The first experiment was successfully completed but the second suffered equipment malfunction on its first flight. I describe the theory of Fourier transformations and give a new understanding of convolutional phase correction computations. I discuss for infrared bolometer calibration procedures, and tabulate test results on nine detectors. I describe methods of improving bolometer sensitivity with immersion optics and with conductive film blackening.

Prospects for a deuterium internal target, tensor polarized by optical pumping: spin exchange

International Nuclear Information System (INIS)

Green, M.C.

1984-01-01

The prospects for a tensor polarized deuterium target (approx. 10 15 atoms/cm 2 ) appropriate for nuclear physics studies in medium and high energy particle storage rings are discussed. Using the technique of electron spin exchange with an optically pumped sodium (or potassium) vapor, we hope to polarize deuterium at a rate approx. 10 17 atoms/sec. Predictions for the deuterium polarization for a particular target cell design will be presented leading to the identification of the required optical pumping power and cell wall depolarization probability to attain optimum performance. The technical obstacles to be surmounted in such a target design will also be discussed

Wall relaxation rates for an optically pumped NA vapor

International Nuclear Information System (INIS)

Swenson, D.R.; Anderson, L.W.

1986-01-01

The wall relaxation rates for an optically pumped Na vapor have been measured for a variety of wall surfaces. We find that fluorocarbon rubber (Fluorel, Viton) and organosilicones (silicone rubber, dry film) at a temperature of 250 C have respectively relaxation rates that correspond on the average to 10 to 15 and 200 to 500 bounces before depolarization occurs. 7 refs., 3 figs

Nonlinear effects in optical pumping of a cold and slow atomic beam

KAUST Repository

Porfido, N.

2015-10-12

By photoionizing hyperfine (HF) levels of the Cs state 62P3/2 in a slow and cold atom beam, we find how their population depends on the excitation laser power. The long time (around 180μs) spent by the slow atoms inside the resonant laser beam is large enough to enable exploration of a unique atom-light interaction regime heavily affected by time-dependent optical pumping. We demonstrate that, under such conditions, the onset of nonlinear effects in the population dynamics and optical pumping occurs at excitation laser intensities much smaller than the conventional respective saturation values. The evolution of population within the HF structure is calculated by numerical integration of the multilevel optical Bloch equations. The agreement between numerical results and experiment outcomes is excellent. All main features in the experimental findings are explained by the occurrence of “dark” and “bright” resonances leading to power-dependent branching coefficients.

Single-walled carbon nanotubes as near-infrared optical biosensors for life sciences and biomedicine.

Science.gov (United States)

Jain, Astha; Homayoun, Aida; Bannister, Christopher W; Yum, Kyungsuk

2015-03-01

Single-walled carbon nanotubes that emit photostable near-infrared fluorescence have emerged as near-infrared optical biosensors for life sciences and biomedicine. Since the discovery of their near-infrared fluorescence, researchers have engineered single-walled carbon nanotubes to function as an optical biosensor that selectively modulates its fluorescence upon binding of target molecules. Here we review the recent advances in the single-walled carbon nanotube-based optical sensing technology for life sciences and biomedicine. We discuss the structure and optical properties of single-walled carbon nanotubes, the mechanisms for molecular recognition and signal transduction in single-walled carbon nanotube complexes, and the recent development of various single-walled carbon nanotube-based optical biosensors. We also discuss the opportunities and challenges to translate this emerging technology into biomedical research and clinical use, including the biological safety of single-walled carbon nanotubes. The advances in single-walled carbon nanotube-based near-infrared optical sensing technology open up a new avenue for in vitro and in vivo biosensing with high sensitivity and high spatial resolution, beneficial for many areas of life sciences and biomedicine. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Early results from the Far Infrared Absolute Spectrophotometer (FIRAS)

Science.gov (United States)

Mather, J. C.; Cheng, E. S.; Shafer, R. A.; Eplee, R. E.; Isaacman, R. B.; Fixsen, D. J.; Read, S. M.; Meyer, S. S.; Weiss, R.; Wright, E. L.

1991-01-01

The Far Infrared Absolute Spectrophotometer (FIRAS) on the Cosmic Background Explorer (COBE) mapped 98 percent of the sky, 60 percent of it twice, before the liquid helium coolant was exhausted. The FIRAS covers the frequency region from 1 to 100/cm with a 7 deg angular resolution. The spectral resolution is 0.2/cm for frequencies less than 20/cm and 0.8/cm for higher frequencies. Preliminary results include: a limit on the deviations from a Planck curve of 1 percent of the peak brightness from 1 to 20/cm, a temperature of 2.735 +/- 0.06 K, a limit on the Comptonization parameter y of 0.001, on the chemical potential parameter mu of 0.01, a strong limit on the existence of a hot smooth intergalactic medium, and a confirmation that the dipole anisotropy spectrum is that of a Doppler shifted blackbody.

Fiber Laser Pumped Continuous-wave Singly-resonant Optical Parametric Oscillator

NARCIS (Netherlands)

Klein, M.E.; Gross, P.; Walde, T.; Boller, Klaus J.; Auerbach, M.; Wessels, P.; Fallnich, C.; Fejer, Martin M.

2002-01-01

We report on the first fiber-pumped CW LiNbO/sub 3/ optical parametric oscillator (OPO). The OPO is singly resonant (SRO) and generates idler wavelengths in the range of 3.0 /spl mu/m to 3.7 /spl mu/m with a maximum output power of 1.9 watt.

Far-infrared spectroscopy in ordered and disordered BaMg1/3Nb2/3O3 microwave ceramics

Science.gov (United States)

Dias, Anderson; Moreira, Roberto Luiz

2003-09-01

Ba(Mg1/3Nb2/3)O3 ceramics with suitable microwave dielectric properties for application in wireless communications and information access technologies were studied by far-infrared spectroscopy. Samples with different B-site ordering degrees, obtained by hydrothermal synthesis followed by sintering at various temperatures, were employed in this investigation. The sixteen infrared modes predicted by factor-group analysis were observed and adjusted according to a four-parameter semiquantum model. The dispersion parameters were determined in order to calculate the real part of the dielectric permittivity and the quality factors associated with the dielectric losses in the microwave region. The materials exhibited increasing ɛ0 and Q values up to 1100 °C, increasing more substantially when the temperature attained 1300 °C. The B-site ordering played an important role on this behavior along with the microstructural evolution above 1100 °C (grain growth), which also increased the phonon lifetime and contributed to the Q improvement. Kramers-Kronig analyses were carried out in all experimental data and the contributions of the main optical polar modes to the dielectric and microwave properties were carefully analyzed in order to identify and attribute the Ba-BO3 external mode, the inner modes related to the O-Mg-O and O-Nb-O bending vibrations, and the stretching modes of each MgO6 and NbO6 octahedron.

High-power extended cavity laser optimized for optical pumping ot Rb

Czech Academy of Sciences Publication Activity Database

Buchta, Zdeněk; Číp, Ondřej; Lazar, Josef

2007-01-01

Roč. 18, č. 9 (2007), N77-N80 ISSN 0957-0233 R&D Pro jects: GA ČR GA102/04/2109; GA MŠk(CZ) LC06007; GA AV ČR IAA200650504; GA AV ČR IAA1065303 Institutional research plan: CEZ:AV0Z20650511 Keywords : laser diode * emission linewidth * diffraction grating * optical pumping * spectroscopy Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.297, year: 2007

Physical optics far field inverse scattering in the time domain

International Nuclear Information System (INIS)

Bleistein, N.

1976-01-01

The physical optics far field inverse scattering (POFFIS) identity relates the phase and range normalized far field back scattering amplitude to the spatial Fourier transform of the characteristic function of the scattering obstacle. The characteristic function is equal to unity in the region occupied by the obstacle and zero elsewhere. The original identity was derived by Bojarski for impulsive point sources. The result is extended to sources of arbitrary time dependence. One obtains an alternative form of Bojarski's POFFIS identity. One also derives a POFFIS identity in the time domain. Numerically synthesized checks on the method are provided

Development of 360-W LD pumped Nd:YAG amplifier with a phase conjugation mirror

International Nuclear Information System (INIS)

Kiriyama, Hiromitsu; Nagai, Toru; Yamakawa, Koichi; Kageyama, Nobuto; Miyajima, Hirofumi; Kan, Hirofumi; Yoshida, Hidetsugu; Nakatsuka, Masahiro

2004-01-01

We report on a high-average-power laser-diode (LD) pumped Nd:YAG master-oscillator-power-amplifier (MOPA) system with a minimum number of element for the single multi-pass zigzag-slab amplifier-stage for pumping of a high-peak and high-average power Ti:sapphire laser system. This phase conjugated system produces an average-power of 362 W at 1 kHz in a 30 ns pulse with an optical-to-optical conversion efficiency of 14%. With an external KTP doubler, this system generates 132 W of green average-output-power at 1 kHz with a conversion efficiency of 60% when pumped at a power level of 222 W. To the best of our knowledge, these results represent the highest average-output-power at both infrared and green wavelengths achieved in a single-amplifier-stage. (author)

Development of Nanostructured Antireflection Coatings for Infrared and Electro-Optical Systems

Directory of Open Access Journals (Sweden)

Gopal G. Pethuraja

2017-07-01

Full Text Available Electro-optic infrared technologies and systems operating from ultraviolet (UV to long-wave infrared (LWIR spectra are being developed for a variety of defense and commercial systems applications. Loss of a significant portion of the incident signal due to reflection limits the performance of electro-optic infrared (IR sensing systems. A critical technology being developed to overcome this limitation and enhance the performance of sensing systems is advanced antireflection (AR coatings. Magnolia is actively involved in the development and advancement of nanostructured AR coatings for a wide variety of defense and commercial applications. Ultrahigh AR performance has been demonstrated for UV to LWIR spectral bands on various substrates. The AR coatings enhance the optical transmission through optical components and devices by significantly minimizing reflection losses, a substantial improvement over conventional thin-film AR coating technologies. Nanostructured AR coatings have been fabricated using a nanomanufacturable self-assembly process on substrates that are transparent for a given spectrum of interest ranging from UV to LWIR. The nanostructured multilayer structures have been designed, developed and optimized for various optoelectronic applications. The optical properties of optical components and sensor substrates coated with AR structures have been measured and the process parameters fine-tuned to achieve a predicted high level of performance. In this paper, we review our latest work on high quality nanostructure-based AR coatings, including recent efforts on the development of nanostructured AR coatings on IR substrates.

Development and application of a far infrared laser

International Nuclear Information System (INIS)

Nakayama, Kazuya; Okajima, Shigeki; Kawahata, Kazuo

2011-01-01

There has been a 40 years history on the application of an infrared laser to interference, polarization and scattering light sources in fusion plasma diagnostics. It is one of important light sources in ITER plasma diagnostics too. In the present review, authors recall the history of the infrared laser development especially of cw infrared lasers. In addition, the state-of-the-art technology for infrared lasers, infrared components and its applications to plasma diagnostics are discussed. (J.P.N.)

Development of suspended core soft glass fibers for far-detuned parametric conversion

Science.gov (United States)

Rampur, Anupamaa; Ciąćka, Piotr; Cimek, Jarosław; Kasztelanic, Rafał; Buczyński, Ryszard; Klimczak, Mariusz

2018-04-01

Light sources utilizing χ (2) parametric conversion combine high brightness with attractive operation wavelengths in the near and mid-infrared. In optical fibers, it is possible to use χ (3) degenerate four-wave mixing in order to obtain signal-to-idler frequency detuning of over 100 THz. We report on a test series of nonlinear soft glass suspended core fibers intended for parametric conversion of 1000-1100 nm signal wavelengths available from an array of mature lasers into the near-to-mid-infrared range of 2700-3500 nm under pumping with an erbium sub-picosecond laser system. The presented discussion includes modelling of the fiber properties, details of their physical development and characterization, and experimental tests of parametric conversion.

ATR and transmission analysis of pigments by means of far infrared spectroscopy.

Science.gov (United States)

Kendix, Elsebeth L; Prati, Silvia; Joseph, Edith; Sciutto, Giorgia; Mazzeo, Rocco

2009-06-01

In the field of FTIR spectroscopy, the far infrared (FIR) spectral region has been so far less investigated than the mid-infrared (MIR), even though it presents great advantages in the characterization of those inorganic compounds, which are inactive in the MIR, such as some art pigments, corrosion products, etc. Furthermore, FIR spectroscopy is complementary to Raman spectroscopy if the fluorescence effects caused by the latter analytical technique are considered. In this paper, ATR in the FIR region is proposed as an alternative method to transmission for the analyses of pigments. This methodology was selected in order to reduce the sample amount needed for analysis, which is a must when examining cultural heritage materials. A selection of pigments have been analyzed in both ATR and transmission mode, and the resulting spectra were compared with each other. To better perform this comparison, an evaluation of the possible effect induced by the thermal treatment needed for the preparation of the polyethylene pellets on the transmission spectra of the samples has been carried out. Therefore, pigments have been analyzed in ATR mode before and after heating them at the same temperature employed for the polyethylene pellet preparation. The results showed that while the heating treatment causes only small changes in the intensity of some bands, the ATR spectra were characterized by differences in both intensity and band shifts towards lower frequencies if compared with those recorded in transmission mode. All pigments' transmission and ATR spectra are presented and discussed, and the ATR method was validated on a real case study.

Infrared and optical light curves of EX Hydrae and VW Hydri

International Nuclear Information System (INIS)

Sherrington, M.R.; Lawson, P.A.; King, A.R.; Jameson, R.F.

1980-01-01

Optical and infrared light curves of EX Hya (V and K) and VW Hyi (J and K) are presented. The infrared colours imply very large discs for these systems. It is also found for EX Hya that the structure of the light curves is non-repeatable. (author)

Development of optical parametric chirped-pulse amplifiers and their applications

Energy Technology Data Exchange (ETDEWEB)

Ishii, Nobuhisa

2006-11-21

In this work, optical pulse amplification by parametric chirped-pulse amplification (OPCPA) has been applied to the generation of high-energy, few-cycle optical pulses in the near-infrared (NIR) and infrared (IR) spectral regions. Amplification of such pulses is ordinarily difficult to achieve by existing techniques of pulse amplification based on standard laser gain media followed by external compression. Potential applications of few-cycle pulses in the IR have also been demonstrated. The NIR OPCPA system produces 0.5-terawatt (10 fs,5 mJ) pulses by use of noncollinearly phase-matched optical parametric amplification and a down-chirping stretcher and up-chirping compressor pair. An IR OPCPA system was also developed which produces 20-gigawatt (20 fs,350 {mu}J) pulses at 2.1 {mu}m. The IR seed pulse is generated by optical rectification of a broadband pulse and therefore it exhibits a self-stabilized carrier-envelope phase (CEP). In the IR OPCPA a common laser source is used to generate the pump and seed resulting in an inherent sub-picosecond optical synchronization between the two pulses. This was achieved by use of a custom-built Nd:YLF picosecond pump pulse amplifier that is directly seeded with optical pulses from a custom-built ultrabroadband Ti:sapphire oscillator. Synchronization between the pump and seed pulses is critical for efficient and stable amplification. Two spectroscopic applications which utilize these unique sources have been demonstrated. First, the visible supercontinuum was generated in a solid-state media by the infrared optical pulses and through which the carrier-envelope phase (CEP) of the driving pulse was measured with an f-to-3f interferometer. This measurement confirms the self-stabilization mechanism of the CEP in a difference frequency generation process and the preservation of the CEP during optical parametric amplification. Second, high-order harmonics with energies extending beyond 200 eV were generated with the few

Optical system design with common aperture for mid-infrared and laser composite guidance

Science.gov (United States)

Zhang, Xuanzhi; Yang, Zijian; Sun, Ting; Yang, Huamei; Han, Kunye; Hu, Bo

2017-02-01

When the field of operation of precision strike missiles is more and more complicated, autonomous seekers will soon encounter serious difficulties, especially with regard to low signature targets and complex scenarios. So the dual-mode sensors combining an imaging sensor with a semi-active laser seeker are conceived to overcome these specific problems. Here the sensors composed a dual field of view mid-infrared thermal imaging camera and a laser range finder have the common optical aperture which produced the minization of seeker construction. The common aperture optical systems for mid-infrared and laser dual-mode guildance have been developed, which could meet the passive middle infrared high-resolution imaging and the active laser high-precision indication and ranging. The optical system had good image quality, and fulfilled the performance requirement of seeker system. The design and expected performance of such a dual-mode optical system will be discussed.

Water Vapor in Titan's Stratosphere from Cassini CIRS Far-Infrared Spectra

Science.gov (United States)

Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bezard, B.;

Optical characterization of semiconductors infrared, Raman, and photoluminescence spectroscopy

CERN Document Server

Perkowitz, Sidney

1993-01-01

This is the first book to explain, illustrate, and compare the most widely used methods in optics: photoluminescence, infrared spectroscopy, and Raman scattering. Written with non-experts in mind, the book develops the background needed to understand the why and how of each technique, but does not require special knowledge of semiconductors or optics. Each method is illustrated with numerous case studies. Practical information drawn from the authors experience is given to help establish optical facilities, including commercial sources for equipment, and experimental details. For industrial sci

Infrared spectromicroscopy and magneto-optical imaging stations at SPring-8

CERN Document Server

Kimura, S; Sada, T; Okuno, M; Matsunami, M; Shinoda, K; Kimura, H; Moriwaki, T; Yamagata, M; Kondo, Y; Yoshimatsu, Y; Takahashi, T; Fukui, K; Kawamoto, T; Ishikawa, T

2001-01-01

At the BL43IR of SPring-8, infrared microanalysis on various kinds of solid specimens under multiple environments with a spatial resolution smaller than 10 mu m in diameter is planned in the infrared region. In order to perform such analysis, two different stations, a multipurpose spectromicroscopy apparatus and a magneto-optical imaging one have been constructed. Measurements on the spatial two-dimensional cross-section of the infrared beam at the spectromicroscopy station have proven that the stations have a good prospective feature in the performance.

Exploring the Dynamics of Superconductors by Time-Resolved Far-Infrared Spectroscopy

International Nuclear Information System (INIS)

Carr, G. L.; Lobo, R. P. S. M.; LaVeigne, J.; Reitze, D. H.; Tanner, D. B.

2000-01-01

We have examined the recombination of excess quasiparticles in superconducting Pb by time-resolved far-infrared spectroscopy using a pulsed synchrotron source. The energy gap shift calculated by Owen and Scalapino [Phys. Rev. Lett. 28, 1559 (1972)] is directly observed, as is the associated reduction in the Cooper pair density. The relaxation process involves a two-component decay; the faster (∼200 ps) is associated with the actual (effective) recombination process, while the slower (∼10 to 100ns) is due to heat transport across the film/substrate interface. The temperature dependence of the recombination process between 0.5T c and 0.85T c is in good agreement with theory

Femtosecond refractive-index tailoring of an optical fiber and phase retrieval from far-field measurements

DEFF Research Database (Denmark)

Savolainen, Juha-Matti; Grüner-Nielsen, Lars; Kristensen, Poul

2013-01-01

A refractive-index change is written inside an optical fiber close to the end face by femtosecond laser light. The induced phase change is measured by analyzing the far-field intensity profiles before and after the irradiation.......A refractive-index change is written inside an optical fiber close to the end face by femtosecond laser light. The induced phase change is measured by analyzing the far-field intensity profiles before and after the irradiation....

An atom trap relying on optical pumping

International Nuclear Information System (INIS)

Bouyer, P.; Lemonde, P.; Ben Dahan, M.; Michaud, A.; Salomon, C.; Dalibard, J.

1994-01-01

We have investigated a new radiation pressure trap which relies on optical pumping and does not require any magnetic field. It employs six circularly polarized divergent beams and works on the red of a J g →J e = J g + 1 atomic transition with J g ≥1/2. We have demonstrated this trap with cesium atoms from a vapour cell using the 852 nm J g = 4→J e = 5 resonance transition. The trap contained up to 3.10 7 atoms in a cloud of 1/√e radius of 330 μm. (orig.)

Far- and near-field optical properties of gold nanoparticle ensembles

International Nuclear Information System (INIS)

Nedyalkov, N N; Dikovska, A O; Dimitrov, I; Nikov, Ru; Atanasov, P A; Toshkova, R A; Gardeva, E G; Yossifova, L S; Alexandrov, M T

2012-01-01

The optical properties of gold nanoparticle clusters are presented from the point of view of their applications in biophotonics, where the absorption and scattering spectra are crucial. Generalised multiparticle Mie theory and finite difference time domain (FDTD) technique are used for theoretical description of the far- and nearfield optical properties of two dimensional nanoparticle ensembles. The system under consideration consists of spherical gold nanoparticles from 20 to 200 nm in diameter, forming 2D clusters in water. The properties of the far-field absorption and scattering spectra as a function of the cluster size, particle dimensions, and interparticle distance are investigated for ordered hexagonal structure of the particle arrays. It is found that the absorption efficiency can be shifted to the IR spectral range by increasing array size and decreasing interparticle distance. The increase in the array size also results in enhancement of the scattering efficiency while the absorption is reduced. The near-field intensity distribution is inhomogeneous over the array, as formation of zones with intensity enhancement of about two orders of magnitude is observed in specific areas. The optical properties of an ensemble whose configuration is reproduced from real experiments of gold nanoparticle deposition onto cancer cells are also presented. The results obtained can be used in designing of nanoparticle arrays with applications in biophotonics, bioimaging and photothermal therapy. (nanosystems)

Far- and near-field optical properties of gold nanoparticle ensembles

Energy Technology Data Exchange (ETDEWEB)

Nedyalkov, N N; Dikovska, A O; Dimitrov, I; Nikov, Ru; Atanasov, P A; Toshkova, R A; Gardeva, E G; Yossifova, L S; Alexandrov, M T

2012-12-31

The optical properties of gold nanoparticle clusters are presented from the point of view of their applications in biophotonics, where the absorption and scattering spectra are crucial. Generalised multiparticle Mie theory and finite difference time domain (FDTD) technique are used for theoretical description of the far- and nearfield optical properties of two dimensional nanoparticle ensembles. The system under consideration consists of spherical gold nanoparticles from 20 to 200 nm in diameter, forming 2D clusters in water. The properties of the far-field absorption and scattering spectra as a function of the cluster size, particle dimensions, and interparticle distance are investigated for ordered hexagonal structure of the particle arrays. It is found that the absorption efficiency can be shifted to the IR spectral range by increasing array size and decreasing interparticle distance. The increase in the array size also results in enhancement of the scattering efficiency while the absorption is reduced. The near-field intensity distribution is inhomogeneous over the array, as formation of zones with intensity enhancement of about two orders of magnitude is observed in specific areas. The optical properties of an ensemble whose configuration is reproduced from real experiments of gold nanoparticle deposition onto cancer cells are also presented. The results obtained can be used in designing of nanoparticle arrays with applications in biophotonics, bioimaging and photothermal therapy. (nanosystems)

Continuous-wave Optically Pumped Lasing of Hybrid Perovskite VCSEL at Green Wavelength

KAUST Repository

Alias, Mohd Sharizal

2017-05-08

We demonstrate the lasing of a perovskite vertical-cavity surface-emitting laser at green wavelengths, which operates under continuous-wave optical pumping at room-temperature by embedding hybrid perovskite between dielectric mirrors deposited at low-temperature.

Continuous-wave Optically Pumped Lasing of Hybrid Perovskite VCSEL at Green Wavelength

KAUST Repository

Alias, Mohd Sharizal; Liu, Zhixiong; Alatawi, Abdullah; Ng, Tien Khee; Wu, Tao; Ooi, Boon S.

2017-01-01

We demonstrate the lasing of a perovskite vertical-cavity surface-emitting laser at green wavelengths, which operates under continuous-wave optical pumping at room-temperature by embedding hybrid perovskite between dielectric mirrors deposited at low-temperature.

A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors

NARCIS (Netherlands)

Baselmans, J.J.A.; Bueno, J.; Yates, Stephen J.C.; Yurduseven, O.; Llombart Juan, N.; Karatsu, K.; Baryshev, A. M.; Ferrarini, L; Endo, A.; Thoen, D.J.; de Visser, P.J.; Janssen, R.M.J.; Murugesan, V.; Driessen, E.F.C.; Coiffard, G.; Martin-Pintado, J.; Hargrave, P.; Griffin, M.

2017-01-01

Aims. Future astrophysics and cosmic microwave background space missions operating in the far-infrared to millimetre part of the spectrum will require very large arrays of ultra-sensitive detectors in combination with high multiplexing factors and efficient low-noise and low-power readout systems.

A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors

NARCIS (Netherlands)

Baselmans, J. J. A.; Bueno, J.; Yates, S. J. C.; Yurduseven, O.; Llombart, N.; Karatsu, K.; Baryshev, A. M.; Ferrari, L.; Endo, A.; Thoen, D. J.; de Visser, P. J.; Janssen, R. M. J.; Murugesan, V.; Driessen, E. F. C.; Coiffard, G.; Martin-Pintado, J.; Hargrave, P.; Griffin, M.

Aims: Future astrophysics and cosmic microwave background space missions operating in the far-infrared to millimetre part of the spectrum will require very large arrays of ultra-sensitive detectors in combination with high multiplexing factors and efficient low-noise and low-power readout systems.

ISO observations of far-infrared rotational emission lines of water vapor toward the supergiant star VY Canis Majoris

OpenAIRE

Neufeld, David A.; Feuchtgruber, Helmut; Harwit, Martin; Melnick, Gary J.

1999-01-01

We report the detection of numerous far-infrared emission lines of water vapor toward the supergiant star VY Canis Majoris. A 29.5 - 45 micron grating scan of VY CMa, obtained using the Short Wavelength Spectrometer (SWS) of the Infrared Space Observatory (ISO) at a spectral resolving power of approximately 2000, reveals at least 41 spectral features due to water vapor that together radiate a total luminosity ~ 25 solar luminosities. In addition to pure rotational transitions within the groun...

Orientation of Ar(3P2) atoms by laser optical pumping

International Nuclear Information System (INIS)

Giberson, K.W.; Hart, M.W.; Hammond, M.S.; Dunning, F.B.; Walters, G.K.

1984-01-01

A beam of argon metastable atoms with a high degree of electron-spin polarization has been produced by optical pumping using an Oxazine 750 dye laser. The beam is suitable for the study of electron spin and orbital orientation dependences in a variety of collision processes

RESEARCH OF THERMO-OPTICAL INHOMOGENEITIES IN Yb-Er GLASS AT DIODE PUMPING

Directory of Open Access Journals (Sweden)

V. Khramov

2016-03-01

Full Text Available Subject of Research. Investigation method of thermo-optical distortions in solid-state lasers was developed and presented. The method can be easily used for research of small diameter (approximately 2 mm active elements. Method. The experimental method described in this paper is based on the registration of deviation of the energy center of the probe beam passing through the thermally stressed active element. Main Results. We have presented experimental results of the thermal lens optical power research in the active element made of Yb-Er glass pumped transversely by a laser diode in the following modes: without generating, free-running and Q-switching. We have submitted obtained dependences of the optical power on the pumping energy. The measurements have been performed for the two polarization components at two wavelengths (632.8 nm and 1550 nm showing the absence of explicit astigmatism of the thermal lens. Practical Relevance. Knowledge of the thermal regime of such lasers gives the possibility for more precise calculation of the resonator parameters in terms of the thermal lens occurrence.

Estimating optical feedback from a chalcogenide fiber in mid-infrared quantum cascade lasers

Directory of Open Access Journals (Sweden)

L. Jumpertz

2016-10-01

Full Text Available The amount of optical feedback originating from a chalcogenide fiber used to couple light from a mid-infrared quantum cascade laser is evaluated experimentally. Threshold reduction measurements on the fibered laser, combined with an analytical study of a rate equations model of the laser under optical feedback, allow estimating the feedback strength between 11% and 15% depending on the fiber cleavage quality. While this remains below the frontier of the chaotic regime, it is sufficient to deeply modify the optical spectrum of a quantum cascade laser. Hence for applications such as gas spectroscopy, where the shape of the optical spectrum is of prime importance, the use of mid-infrared optical isolators may be necessary for fibered quantum cascade lasers to be fully exploited.

Image transmission in mid-IR using a solid state laser pumped optical parametric oscillator

Science.gov (United States)

Prasad, Narasimha S.; Kratovil, Pat; Magee, James R.

2002-04-01

In this paper, image transmission using a mid-wave IR (MWIR) optical transceiver based free-space data link under low visibility conditions is presented. The all-solid-state MWIR transceiver primarily consisted of a passively Q-switched, short-pulsed Nd:YAG laser pumping a periodically poled lithium niobate (PPLN) based optical parametric oscillator and a Dember effect detector. The MILES transceiver generates pulse position waveforms. The optical data link consisting of transmitter drive electronics, pulse conditioning electronics and a computer generating pulses compatible with the 2400-baud rate RS232 receiver was utilized. Data formatting and RS232 transmission and reception were achieved using a computer. Data formatting transformed an arbitrary image file format compatible with the basic operation of pump laser. Images were transmitted at a date rate of 2400 kbits/sec with 16 bits/pixel. Test images consisting of 50X40 pixels and 100X80 pixels were transmitted through free-space filled with light fog up to 120 ft. Besides optical parametric oscillators, the proposed concept can be extended to optical parametric amplifiers, Raman lasers and other nonlinear optical devices to achieve multi-functionality.

Tunable far infrared laser spectroscopy of van der Waals bonds: Ar-NH3

International Nuclear Information System (INIS)

Gwo, Dz-Hung; California Univ., Berkeley, CA

1989-11-01

Hyperfine resolved vibration-rotation-tunneling spectra of Ar--NH 3 and (NH 3 ) 2 , generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar--NH 3 , and the other six belong to (NH 3 ) 2 . To facilitate the intermolecular vibrational assignment for Ar--NH 3 , a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states. An anomalous vibronically allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar--NH 3 centered at 26.470633(17) cm -1 can correlate only to either the fundamental dimeric stretching band for the A 2 states with the NH 3 inversional quantum number v i = 1, or the K a = 0 left-arrow 0 subband of the lowest internal-rotation-inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require far infrared data and a dynamical model incorporating a potential surface

Continuous-wave optically pumped green perovskite vertical-cavity surface-emitter

KAUST Repository

Alias, Mohd Sharizal

2017-09-11

We report an optically pumped green perovskite vertical-cavity surface-emitter operating in continuous-wave (CW) with a power density threshold of ~89 kW/cm2. The device has an active region of CH3NH3PbBr3 embedded in a dielectric microcavity; this feat was achieved with a combination of optimal spectral alignment of the optical cavity modes with the perovskite optical gain, an adequate Q-factor of the microcavity, adequate thermal stability, and improved material quality with a smooth, passivated, and annealed thin active layer. Our results signify a way towards efficient CW perovskite emitter operation and electrical injection using low-cost fabrication methods for addressing monolithic optoelectronic integration and lasing in the green gap.

Optical vortex generation from a diode-pumped alexandrite laser

Science.gov (United States)

Thomas, G. M.; Minassian, A.; Damzen, M. J.

2018-04-01

We present the demonstration of an optical vortex mode directly generated from a diode-pumped alexandrite slab laser, operating in the bounce geometry. This is the first demonstration of an optical vortex mode generated from an alexandrite laser or from any other vibronic laser. An output power of 2 W for a vortex mode with a ‘topological charge’ of 1 was achieved and the laser was made to oscillate with both left- and right-handed vorticity. The laser operated at two distinct wavelengths simultaneously, 755 and 759 nm, due to birefringent filtering in the alexandrite gain medium. The result offers the prospect of broadly wavelength tunable vortex generation directly from a laser.

Installation And Test Of Electron Beam Generation System To Produce Far-Infrared Radiation And X-Ray Pulses

International Nuclear Information System (INIS)

Wichaisirimongkol, Pathom; Jinamoon, Witoon; Khangrang, Nopadon; Kusoljariyakul, Keerati; Rhodes, Michael W.; Rimjaem, Sakhorn; Saisut, Jatuporn; Chitrlada, Thongbai; Vilaithong, Thiraphat; Wiedemann, Helmut

2005-10-01

SURIYA project at the Fast Neutron Research Facility, Chiang Mai University, aims to establish a facility to generate femtosecond electron beams. This electron beam can be used to generate high intensity far-infrared radiation and ultra-short X-ray pulses. The main components of the system are a 3 MeV RF electron gun with a thermionic cathode, an a-magnet as a bunch compressor, and post acceleration 15-20 MeV by a linear accelerator (linac). Between the main components, there are focusing quadrupole magnets and steering magnets to maintain the electron beam within a high vacuum tube. At the end of the beam transport line, a dipole magnet has been installed to function as a beam dump and an energy spectrometer. After the installation and testing of individual major components were completed, we have been investigating the generation of the electron beam, intense far- infrared radiation and ultra short X-ray pulses

Towards supercontinuum-driven hyperspectral microscopy in the mid-infrared

DEFF Research Database (Denmark)

Lindsay, I. D.; Valle, S.; Ward, J.

2016-01-01

The extension of supercontinuum (SC) sources into the mid-infrared, via the use of fluoride and chalcogenide optical fibers, potentially offers the high radiance of a laser combined with spectral coverage far exceeding that of typical tunable lasers and comparable to traditional black-body emitte...

Modeling of the gain distribution for diode pumping of a solid-state laser rod with nonimaging optics.

Science.gov (United States)

Koshel, R J; Walmsley, I A

1993-03-20

We investigate the absorption distribution in a cylindrical gain medium that is pumped by a source of distributed laser diodes by means of a pump cavity developed from the edge-ray principle of nonimaging optics. The performance of this pumping arrangement is studied by using a nonsequential, numerical, three-dimensional ray-tracing scheme. A figure of merit is defined for the pump cavities that takes into account the coupling efficiency and uniformity of the absorption distribution. It is found that the nonimaging pump cavity maintains a high coupling efficiency with extended two-dimensional diode arrays and obtains a fairly uniform absorption distribution. The nonimaging cavity is compared with two other designs: a close-coupled side-pumped cavity and an imaging design in the form of a elliptical cavity. The nonimaging cavity has a better figure of merit per diode than these two designs. It also permits the use of an extended, sparse, two-dimensional diode array, which reduces thermal loading of the source and eliminates all cavity optics other than the main reflector.

Future directions in 980-nm pump lasers: submarine deployment to low-cost watt-class terrestrial pumps

Science.gov (United States)

Gulgazov, Vadim N.; Jackson, Gordon S.; Lascola, Kevin M.; Major, Jo S.; Parke, Ross; Richard, Tim; Rossin, Victor V.; Zhang, Kai

1999-09-01

The demands of global bandwidth and distribution are rising rapidly as Internet usage grows. This fundamentally means that more photons are flowing within optical cables. While transmitting sources launches some optical power, the majority of the optical power that is present within modern telecommunication systems originates from optical amplifiers. In addition, modern optical amplifiers offer flat optical gain over broad wavelength bands, thus making possible dense wavelength de-multiplexing (DWDM) systems. Optical amplifier performance, and by extension the performance of the laser pumps that drive them, is central to the future growth of both optical transmission and distribution systems. Erbium-doped amplifiers currently dominate optical amplifier usage. These amplifiers absorb pump light at 980 nm and/or 1480 nm, and achieve gain at wavelengths around 1550 nm. 980 nm pumps achieve better noise figures and are therefore used for the amplification of small signals. Due to the quantum defect, 1480 nm lasers deliver more signal photon per incident photon. In addition, 1480 nm lasers are less expensive than 980 nm lasers. Thus, 1480 nm pump lasers are used for amplification in situations where noise is not critical. The combination of these traits leads to the situation where many amplifiers contain 980 nm lasers to pump the input section of the Er- doped fiber with 1480 nm lasers being used to pump the latter section of Er fiber. This can be thought of as using 980 nm lasers to power an optical pre-amplifier with the power amplification function being pump with 1480 nm radiation. This paper will focus on 980 nm pump lasers and the impact that advances in 980 nm pump technology will have on optical amplification systems. Currently, 980 nm technology is rapidly advancing in two areas, power and reliability. Improving reliability is becoming increasingly important as amplifiers move towards employing more pump lasers and using these pump lasers without redundancy

Ultrafast carrier dynamics in bilayer graphene studied by broadband infrared pump-probe spectroscopy

Science.gov (United States)

Limmer, Thomas; da Como, Enrico; Niggebaum, Alexander; Feldmann, Jochen

2010-03-01

Recently, bilayer graphene gained a large interest because of its electrically tunable gap appearing in the middle infrared part of the electromagnetic spectrum. This feature is expected to open a number of applications of bilayer graphene in optoelectronics. In this communication we report on the first pump-probe experiment on a single bilayer flake with an unprecedented probe photon energy interval (0.25 -- 1.3 eV). Single flakes were prepared by mechanical exfoliation of graphite and transferred to calcium fluoride substrates. When illuminated with 800 nm (1.5 eV) pump pulses the induced change in transmission shows an ultrafast saturation of the interband transitions from 1.3 to 0.5 eV. In this energy range the saturation recovery occurs within 3 ps and is consistent with an ultrafast relaxation of hot carriers. Interestingly, we report on the observation of a resonance at 0.4 eV characterized by a longer dynamics. The results are discussed considering many-body interactions.

The laser control system for the TRIUMF optically pumped polarized H- ion source

International Nuclear Information System (INIS)

Kadantsev, S.G.; Levy, C.D.P.; Mouat, M.M.

1994-08-01

The optically pumped polarized H - ion source at TRIUMF produces up to 100 μΑ dc of 78% polarized beam within an emittance of 1.0 π mm mrad and is now being prepared for an upcoming experiment at TRIUMF that will measure parity violation in pp scattering at 230 MeV. The optical pumping is accomplished by argon laser pumped Ti-sapphire lasers. The laser control system provides monitoring and precision control of the lasers for fast spin reversal up to 200 s -1 . To solve the problems of laser power and frequency stabilization during fast spin flipping, techniques and algorithms have been developed that significantly reduce the variation of laser frequency and power between spin states. The upgraded Faraday rotation system allows synchronous measurement of Rb thickness and polarization while spin flipping. The X Window environment provides both local and remote control to laser operators via a local area network and X window terminals. In this new environment issues such as access authorization, response time, operator interface consistency and ease of use are of particular importance. (author)

Optical pumping of Rb by Ti:Sa laser and high-power laser diode

Czech Academy of Sciences Publication Activity Database

Buchta, Zdeněk; Rychnovský, Jan; Lazar, Josef

2006-01-01

Roč. 8, č. 1 (2006), s. 350-354 ISSN 1454-4164 R&D Projects: GA AV ČR IAA1065303; GA ČR GA102/04/2109 Institutional research plan: CEZ:AV0Z20650511 Keywords : optical pumping * Ti:Sa laser * laser diode * emission linewidth * spectroscopy * laser frequency stabilization Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.106, year: 2006

Possibility of observation of polaron normal modes at the far-infrared spectrum of acetanilide and related organics

Science.gov (United States)

Kalosakas, G.; Aubry, S.; Tsironis, G. P.

1998-10-01

We use a stationary and normal mode analysis of the semiclassical Holstein model in order to connect the low-frequency linear polaron modes to low-lying far-infrared lines of the acetanilide spectrum and through parameter fitting we comment on the validity of the polaron results in this system.

Diatomic infrared gas-dynamic laser

International Nuclear Information System (INIS)

Mckenzie, R.L.

1971-01-01

A laser is provided which utilizes the infrared vibration rotation transitions of a diatomic gas such as carbon monoxide. The laser action is produced by an active diatomic gas such as carbon monoxide mixed with a vibrationally resonant pumping gas such as nitrogen. In addition, a noble gas such as argon may be employed as a third gas in the mixture. The gas mixture contains from 1 to 80 vol percent of the active gas based on the pumping gas, and the third gas, if used, can constitute up to 90 percent of the total gas volume. A number of significantly different wavelengths can be produced by the laser. A single laser may contain several optical resonators at different locations, so that the desired wave length can be selected at will

Far-Infrared Emission Characteristics and Wear Comfort Property of ZrC-Imbedded Heat Storage Knitted Fabrics for Emotional Garments

Directory of Open Access Journals (Sweden)

Kim Hyun Ah

2017-06-01

Full Text Available This study examined the far-infrared emission characteristics and wear comfort properties of ZrC-imbedded heat storage knitted fabrics. For this purpose, ZrC-imbedded, heat storage PET (polyethylene terephthalate was spun from high-viscosity PET with imbedded ZrC powder on the core part and low-viscosity PET on the sheath part using a conjugated spinning method. ZrC-imbedded PET knitted fabric was also prepared and its physical properties were measured and compared with those of regular PET knitted fabric. In addition, ingredient analysis and the far-infrared emission characteristics of the ZrC-imbedded knitted fabrics were analyzed by energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The thermal properties, moisture absorption, and drying properties of the ZrC-imbedded PET knitted fabric were measured and compared with those of the regular PET knitted fabric. The mechanical properties using the FAST (fabric assurance by simple testing system and the dye affinity of the ZrC-imbedded knitted fabric were also measured and compared with those of regular PET knitted fabric.

Application of Stark Tuned Laser for Interferometry and Polarimetry in Plasmas

International Nuclear Information System (INIS)

H.K. Park; K.C. Lee; B. Deng; C.W. Domier; M. Johnson; B. Nathan; N.C. Luhmann, Jr.

2001-01-01

A Stark-tuned optically pumped far-infrared CH(subscript ''3'')OH laser at 119 mm has been successfully applied in the Far Infrared Tangential Interferometer/Polarimeter (FIReTIP) system for the National Spherical Torus Experiment (NSTX). The system will provide temporally and radially resolved 2-D electron density profile [n(subscript ''e'')(r,t)] and toroidal field profile [B(subscript ''T'')(r,t)] data. In the 2001 campaign, a single channel interferometer system has been operated and tested for the Faraday rotation measurement. A plan for improvement and upgrading of the FIReTIP is discussed

An optical super-microscope for far-field, real-time imaging beyond the diffraction limit.

Science.gov (United States)

Wong, Alex M H; Eleftheriades, George V

2013-01-01

Optical microscopy suffers from a fundamental resolution limitation arising from the diffractive nature of light. While current solutions to sub-diffraction optical microscopy involve combinations of near-field, non-linear and fine scanning operations, we hereby propose and demonstrate the optical super-microscope (OSM) - a superoscillation-based linear imaging system with far-field working and observation distances - which can image an object in real-time and with sub-diffraction resolution. With our proof-of-principle prototype we report a point spread function with a spot size clearly reduced from the diffraction limit, and demonstrate corresponding improvements in two-point resolution experiments. Harnessing a new understanding of superoscillations, based on antenna array theory, our OSM achieves far-field, sub-diffraction optical imaging of an object without the need for fine scanning, data post-processing or object pre-treatment. Hence the OSM can be used in a wide variety of imaging applications beyond the diffraction limit, including real-time imaging of moving objects.

Cleanability evaluation of ceramic glazes with nanometer far-infrared materials using contact angle measurement.

Science.gov (United States)

Wang, Lijuan; Liang, Jinsheng; Di, Xingfu; Tang, Qingguo

2014-05-01

The cleanability of easy-to-clean ceramic glazes doped with nanometer far-infrared materials was compared with that of some high-quality household ceramic glazes from the market. The cleanability was evaluated by the contact angle measurement using a sessile drop method with a Dataphysics OCA-30 contact angle analyzer. The results showed that the difference of contact angles of water on the glazes before soiling and after cleaning could be used as a parameter for evaluating the cleanability of the glazes. The relationship between cleanability and surface properties, such as surface free energy and surface topography, was investigated. The surface free energy of the samples and their components were calculated using van Oss acid-base approach. By measuring advancing and receding contact angles, the contact angle hysteresis of the ceramic glazes due to the surface topography was investigated. It was shown that the cleanability of ceramic glazes containing nanometer far-infrared materials (NFIM) is better than that of household ceramic glazes from market, due to a higher ratio of electron-acceptor parameter to electron-donor parameter, which led to the effect of water hydration as well as better hydrophilic property and increased smoothness. The contact angle measurement not only accurately evaluates the cleanability of the ceramic glazes, but also has a contribution to the study of cleanability theory. Moreover, this method is simple, convenient and less sample-consumption.

The Far-Infrared Luminosity Function and Star Formation Rate Density for Dust Obscured Galaxies in the Bootes Field

Science.gov (United States)

Calanog, Jae Alyson; Wardlow, J. L.; Fu, H.; Cooray, A. R.; HerMES

2013-01-01

We present the far-Infrared (FIR) luminosity function (LF) and the star-formation rate density (SFRD) for dust-obscured galaxies (DOGs) in the Bootes field at redshift 2. These galaxies are selected by having a large rest frame mid-IR to UV flux density ratio ( > 1000) and are expected to be some of the most luminous and heavily obscured galaxies in the Universe at this epoch. Photometric redshifts for DOGs are estimated from optical and mid-IR data using empirically derived low resolution spectral templates for AGN and galaxies. We use HerMES Herschel-SPIRE data to fit a modified blackbody to calculate the FIR luminosity (LFIR) and dust temperature (Td) for all DOGs individually detected in SPIRE maps. A stacking analyses was implemented to measure a median sub-mm flux of undetected DOGs. We find that DOGs have LIR and Td that are similar with the sub-millimeter galaxy (SMG) population, suggesting these two populations are related. The DOG LF and SFRD at 2 are calculated and compared to SMGs.

A new software tool for computing Earth's atmospheric transmission of near- and far-infrared radiation

Science.gov (United States)

Lord, Steven D.