WorldWideScience

Sample records for uv optical cavity

  1. An advanced UV optical cavity for the European FEL project

    CERN Document Server

    Poole, M W; Chesworth, A A; Clarke, J A; Fell, B; Hill, C; Marl, R; Mullacrane, I D; Reid, R J

    2000-01-01

    A European collaboration is constructing a short wavelength FEL for the ELETTRA storage ring. The optical cavity has been designed and constructed at Daresbury Laboratory for delivery to Sincrotrone Trieste in Autumn 1999, following commissioning tests over the Summer. Initial FEL operation will be at 350 nm but subsequently down to 200 nm or less and mirrors will be 40 mm diameter. The 32 m optical cavity is controllable to 0.01 mu rad in mirror pitch and yaw using digital piezo translators. A novel feature is the simultaneous presence of three remotely interchangeable mirrors to extend the tuning range and also to interchange damaged mirrors immediately. In addition, a transfer arm and load-lock arrangement will permit a mirror to be withdrawn from the chamber and replaced without disruption to the UHV system. The FEL is designed to operate at high power (1-10 W) and multi-watt spontaneous emission is also present: power loading has been investigated by FEA analysis and has necessitated specification of a w...

  2. Optical cavity furnace for semiconductor wafer processing

    Science.gov (United States)

    Sopori, Bhushan L.

    2014-08-05

    An optical cavity furnace 10 having multiple optical energy sources 12 associated with an optical cavity 18 of the furnace. The multiple optical energy sources 12 may be lamps or other devices suitable for producing an appropriate level of optical energy. The optical cavity furnace 10 may also include one or more reflectors 14 and one or more walls 16 associated with the optical energy sources 12 such that the reflectors 14 and walls 16 define the optical cavity 18. The walls 16 may have any desired configuration or shape to enhance operation of the furnace as an optical cavity 18. The optical energy sources 12 may be positioned at any location with respect to the reflectors 14 and walls defining the optical cavity. The optical cavity furnace 10 may further include a semiconductor wafer transport system 22 for transporting one or more semiconductor wafers 20 through the optical cavity.

  3. Tuned optical cavity magnetometer

    Science.gov (United States)

    Okandan, Murat; Schwindt, Peter

    2010-11-02

    An atomic magnetometer is disclosed which utilizes an optical cavity formed from a grating and a mirror, with a vapor cell containing an alkali metal vapor located inside the optical cavity. Lasers are used to magnetically polarize the alkali metal vapor and to probe the vapor and generate a diffracted laser beam which can be used to sense a magnetic field. Electrostatic actuators can be used in the magnetometer for positioning of the mirror, or for modulation thereof. Another optical cavity can also be formed from the mirror and a second grating for sensing, adjusting, or stabilizing the position of the mirror.

  4. Optically coupled cavities for wavelength switching

    Energy Technology Data Exchange (ETDEWEB)

    Costazo-Caso, Pablo A; Granieri, Sergio; Siahmakoun, Azad, E-mail: pcostanzo@ing.unlp.edu.ar, E-mail: granieri@rose-hulman.edu, E-mail: siahmako@rose-hulman.edu [Department of Physics and Optical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803 (United States)

    2011-01-01

    An optical bistable device which presents hysteresis behavior is proposed and experimentally demonstrated. The system finds applications in wavelength switching, pulse reshaping and optical bistability. It is based on two optically coupled cavities named master and slave. Each cavity includes a semiconductor optical amplifier (SOA), acting as the gain medium of the laser, and two pair of fiber Bragg gratings (FBG) which define the lasing wavelength (being different in each cavity). Finally, a variable optical coupler (VOC) is employed to couple both cavities. Experimental characterization of the system performance is made analyzing the effects of the coupling coefficient between the two cavities and the driving current in each SOA. The properties of the hysteretic bistable curve and switching can be controlled by adjusting these parameters and the loss in the cavities. By selecting the output wavelength ({lambda}{sub 1} or {lambda}{sub 2}) with an external filter it is possible to choose either the invert or non-invert switched signal. Experiments were developed employing both optical discrete components and a photonic integrated circuit. They show that for 8 m-long cavities the maximum switching frequency is about 500 KHz, and for 4 m-long cavities a minimum rise-time about 21 ns was measured. The switching time can be reduced by shortening the cavity lengths and using photonic integrated circuits.

  5. Harnessing the mode mixing in optical fiber-tip cavities

    International Nuclear Information System (INIS)

    Podoliak, Nina; Horak, Peter; Takahashi, Hiroki; Keller, Matthias

    2017-01-01

    We present a systematic numerical study of Fabry–Pérot optical cavities with Gaussian-shape mirrors formed between tips of optical fibers. Such cavities can be fabricated by laser machining of fiber tips and are promising systems for achieving strong coupling between atomic particles and an optical field as required for quantum information applications. Using a mode mixing matrix method, we analyze the cavity optical eigenmodes and corresponding losses depending on a range of cavity-shape parameters, such as mirror radius of curvature, indentation depth and cavity length. The Gaussian shape of the mirrors causes mixing of optical modes in the cavity. We investigate the effect of the mode mixing on the coherent atom-cavity coupling as well as the mode matching between the cavity and a single-mode optical fiber. While the mode mixing is associated with increased cavity losses, it can also lead to an enhancement of the local optical field. We demonstrate that around the resonance between the fundamental and 2nd order Laguerre–Gaussian modes of the cavity it is possible to obtain 50% enhancement of the atom-cavity coupling at the cavity center while still maintaining low cavity losses and high cavity-fiber optical coupling. (paper)

  6. Over 8 W high peak power UV laser with a high power Q-switched Nd:YVO4 oscillator and the compact extra-cavity sum-frequency mixing

    International Nuclear Information System (INIS)

    Yan, X P; Liu, Q; Gong, M; Wang, D S; Fu, X

    2009-01-01

    A 8.2 W UV laser was reported with the compact extra-cavity sum-frequency mixing. The IR fundamental frequency source was a high power and high beam quality Q-switched Nd:YVO 4 oscillator. 38 W fundamental frequency laser at 1064 nm was obtained at the pulse repetition rate of 450 kHz with the beam quality factors of M 2 x = 1.27, M 2 y = 1.21. The type I and type II phase-matched LBO crystals were used as the extra-cavity frequency doubling and mixing crystals respectively. At 38 kHz, 8.2 W UV laser at 355 nm was achieved with the pulse duration of 8 ns corresponding to the pulse peak power as high as 27 kW, and the optical-optical conversion efficiency from IR to UV was 25.6%. The output characteristics of the IR and the harmonic generations varying with the pulse repetition rate were also investigated detailedly

  7. UV-cured polymer optics

    Science.gov (United States)

    Piñón, Victor; Santiago, Freddie; Vogelsberg, Ashten; Davenport, Amelia; Cramer, Neil

    2017-10-01

    Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

  8. Optical cavity cooling of mechanical modes of a semiconductor nanomembrane

    DEFF Research Database (Denmark)

    Usami, Koji; Naesby, A.; Bagci, Tolga

    2012-01-01

    Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high-quality-factor and......Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high...

  9. UV Bandpass Optical Filter for Microspectometers

    NARCIS (Netherlands)

    Correia, J.H.; Emadi, A.R.; Wolffenbuttel, R.F.

    2006-01-01

    This paper describes the design and modeling of a UV bandpass optical filter for microspectrometers. The materials used for fabricating the multilayer UV filter are: silicon dioxide (SiO2), titanium dioxide (TiO2) and yttrium oxide (Y2O3). The optical filter shows a bandpass response wavelength in

  10. Cavity-mirror degradation in the deep-UV FEL

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, K.; Yamazaki, T.; Sei, N. [Electrotechnical Lab., Ibaraki (Japan)] [and others

    1995-12-31

    It is known that the degradation of dielectric multilayer mirrors used in short wavelength free-electron lasers (FELs) is caused by the carbon contamination on the mirror surface and the defects inside the dielectrics. We reported last year that the degraded dielectric multilayer mirrors can be repaired with both surface treatment by RF-induced oxygen plasma and thermal annealing. However, such a mirror degradation is still one of the most critical issues in the deep ultraviolet (UV) FELs, because the fundamental undulator radiation resonating in the laser cavity, the intensity of which is much higher than that of higher harmonics, can be sufficiently energetic to cause the mirror degradation through photochemical reactions. We are investigating the mirror degradation mainly in the deep UV region down to 240 nm. The experimental results will be shown. The mirror degradation mechanism will be discussed.

  11. All-optical tunable photonic crystal cavity

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    We demonstrate an ultra-small photonic crystal cavity with two resonant modes. An all-optical tuning operation based on the free-carrier plasma effect is, for the first time, realized utilizing a continuous wave light source. The termo-optical effect is minimized by isoproponal infiltration...

  12. Femtojoule-scale all-optical latching and modulation via cavity nonlinear optics.

    Science.gov (United States)

    Kwon, Yeong-Dae; Armen, Michael A; Mabuchi, Hideo

    2013-11-15

    We experimentally characterize Hopf bifurcation phenomena at femtojoule energy scales in a multiatom cavity quantum electrodynamical (cavity QED) system and demonstrate how such behaviors can be exploited in the design of all-optical memory and modulation devices. The data are analyzed by using a semiclassical model that explicitly treats heterogeneous coupling of atoms to the cavity mode. Our results highlight the interest of cavity QED systems for ultralow power photonic signal processing as well as for fundamental studies of mesoscopic nonlinear dynamics.

  13. Production of High Intracavity UV Power From a CW Laser Source

    Science.gov (United States)

    David, R. T.; Chyba, T. H.; Keppel, C. E.; Gaskell, D.; Ent, R.

    1998-01-01

    The goal of this research project is to create a prototype high power CW source of ultraviolet (UV) photons for photon-electron scattering at the Thomas Jefferson National Accelerator Facility (TJNAF), Hall B. The facility will use optical resonant cavities to produce a high photon flux. The technical approach will be to frequency-double the 514.5 mn light from an Argon-Ion Laser to create 0.1 to 1.0 watt in the UV. The produced UV power will be stored in a resonant cavity to generate an high intracavity UV power of 102 to 103 watts. The specific aim of this project is to first design and construct the low-Q doubling cavity and lock it to the Argon-Ion wavelength. Secondly, the existing 514.5 nm high-Q build-up cavity and its locking electronics will be modified to create high intracavity UV power. The entire system will then be characterized and evaluated for possible beam line use.

  14. Dissipative preparation of entanglement in optical cavities

    DEFF Research Database (Denmark)

    Kastoryano, Michael James; Reiter, Florentin; Sørensen, Anders Søndberg

    2011-01-01

    We propose a novel scheme for the preparation of a maximally entangled state of two atoms in an optical cavity. Starting from an arbitrary initial state, a singlet state is prepared as the unique fixed point of a dissipative quantum dynamical process. In our scheme, cavity decay is no longer...

  15. Temporal dynamics of all-optical switching in Photonic Crystal Cavity

    DEFF Research Database (Denmark)

    Colman, Pierre; Heuck, Mikkel; Yu, Yi

    2014-01-01

    The temporal dynamics of all-optical switching has been investigated in a Photonic Crystal Cavity with a 150fs-40aJ/pulse resolution. This allowed observing for the first time effects like pulse reshaping, pulse delay and intra-cavity Four-Wave-Mixing.......The temporal dynamics of all-optical switching has been investigated in a Photonic Crystal Cavity with a 150fs-40aJ/pulse resolution. This allowed observing for the first time effects like pulse reshaping, pulse delay and intra-cavity Four-Wave-Mixing....

  16. Cavity cooling of an optically levitated submicron particle

    Science.gov (United States)

    Kiesel, Nikolai; Blaser, Florian; Delić, Uroš; Grass, David; Kaltenbaek, Rainer; Aspelmeyer, Markus

    2013-01-01

    The coupling of a levitated submicron particle and an optical cavity field promises access to a unique parameter regime both for macroscopic quantum experiments and for high-precision force sensing. We report a demonstration of such controlled interactions by cavity cooling the center-of-mass motion of an optically trapped submicron particle. This paves the way for a light–matter interface that can enable room-temperature quantum experiments with mesoscopic mechanical systems. PMID:23940352

  17. All-Optical Switching in Photonic Crystal Cavities

    DEFF Research Database (Denmark)

    Heuck, Mikkel

    All-Optical switching in photonic crystal waveguide-cavity structures is studied predominantly theoretically and numerically, but also from an experimental point of view. We have calculated the first order perturbations to the resonance frequency and decay rate of cavity modes, using a mathematical...... exhibiting Fano resonances. These devices were predicted to be superior to structures with the more well-known Lorentzian line shape in terms of energy consumption and switching contrast. Finally, the mathematical framework of optimal control theory was employed as a general setting, in which the optical...... faster than the photon lifetime by utilizing interference effects....

  18. Scattering-free optical levitation of a cavity mirror.

    Science.gov (United States)

    Guccione, G; Hosseini, M; Adlong, S; Johnsson, M T; Hope, J; Buchler, B C; Lam, P K

    2013-11-01

    We demonstrate the feasibility of levitating a small mirror using only radiation pressure. In our scheme, the mirror is supported by a tripod where each leg of the tripod is a Fabry-Perot cavity. The macroscopic state of the mirror is coherently coupled to the supporting cavity modes allowing coherent interrogation and manipulation of the mirror motion. The proposed scheme is an extreme example of the optical spring, where a mechanical oscillator is isolated from the environment and its mechanical frequency and macroscopic state can be manipulated solely through optical fields. We model the stability of the system and find a three-dimensional lattice of trapping points where cavity resonances allow for buildup of optical field sufficient to support the weight of the mirror. Our scheme offers a unique platform for studying quantum and classical optomechanics and can potentially be used for precision gravitational field sensing and quantum state generation.

  19. Intra-Cavity Total Reflection For High Sensitivity Measurement Of Optical Properties

    Science.gov (United States)

    Pipino, Andrew Charles Rule

    1999-11-16

    An optical cavity resonator device is provided for conducting sensitive murement of optical absorption by matter in any state with diffraction-limited spatial resolution through utilization of total internal reflection within a high-Q (high quality, low loss) optical cavity. Intracavity total reflection generates an evanescent wave that decays exponentially in space at a point external to the cavity, thereby providing a localized region where absorbing materials can be sensitively probed through alteration of the Q-factor of the otherwise isolated cavity. When a laser pulse is injected into the cavity and passes through the evanescent state, an amplitude loss resulting from absorption is incurred that reduces the lifetime of the pulse in the cavity. By monitoring the decay of the injected pulse, the absorption coefficient of manner within the evanescent wave region is accurately obtained from the decay time measurement.

  20. Noise-Immune Cavity-Enhanced Optical Frequency Comb Spectroscopy

    Science.gov (United States)

    Rutkowski, Lucile; Khodabakhsh, Amir; Johanssson, Alexandra C.; Foltynowicz, Aleksandra

    2015-06-01

    We present noise-immune cavity-enhanced optical frequency comb spectroscopy (NICE-OFCS), a recently developed technique for sensitive, broadband, and high resolution spectroscopy. In NICE-OFCS an optical frequency comb (OFC) is locked to a high finesse cavity and phase-modulated at a frequency precisely equal to (a multiple of) the cavity free spectral range. Since each comb line and sideband is transmitted through a separate cavity mode in exactly the same way, any residual frequency noise on the OFC relative to the cavity affects each component in an identical manner. The transmitted intensity contains a beat signal at the modulation frequency that is immune to frequency-to-amplitude noise conversion by the cavity, in a way similar to continuous wave noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS). The light transmitted through the cavity is detected with a fast-scanning Fourier-transform spectrometer (FTS) and the NICE-OFCS signal is obtained by fast Fourier transform of the synchronously demodulated interferogram. Our NICE-OFCS system is based on an Er:fiber femtosecond laser locked to a cavity with a finesse of ˜9000 and a fast-scanning FTS equipped with a high-bandwidth commercial detector. We measured NICE-OFCS signals from the 3νb{1}+νb{3} overtone band of CO_2 around 1.57 μm and achieved absorption sensitivity 6.4×10-11cm-1 Hz-1/2 per spectral element, corresponding to a minimum detectable CO_2 concentration of 25 ppb after 330 s integration time. We will describe the principles of the technique and its technical implementation, and discuss the spectral lineshapes of the NICE-OFCS signals. A. Khodabakhsh, C. Abd Alrahman, and A. Foltynowicz, Opt. Lett. 39, 5034-5037 (2014). J. Ye, L. S. Ma, and J. L. Hall, J. Opt. Soc. Am. B 15, 6-15 (1998). A. Khodabakhsh, A. C. Johansson, and A. Foltynowicz, Appl. Phys. B (2015) doi:10.1007/s00340-015-6010-7.

  1. UV written 1x8 optical splitters

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of 1x8 optical power splitters made by direct UV writing is presented. Design and optimization of the process as well as the performance of the fabricated components are discussed.......In this paper the first demonstration of 1x8 optical power splitters made by direct UV writing is presented. Design and optimization of the process as well as the performance of the fabricated components are discussed....

  2. Lateral shearing optical gradient force in coupled nanobeam photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Du, Han; Zhang, Xingwang; Chau, Fook Siong; Zhou, Guangya, E-mail: mpezgy@nus.edu.sg [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575 (Singapore); Deng, Jie [Institute of Materials Research and Engineering, 2 Fusionopolis Way, Innovis, #08-03, Singapore 138634 (Singapore); Zhao, Yunshan [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583 (Singapore)

    2016-04-25

    We report the experimental observation of lateral shearing optical gradient forces in nanoelectromechanical systems (NEMS) controlled dual-coupled photonic crystal (PhC) nanobeam cavities. With an on-chip integrated NEMS actuator, the coupled cavities can be mechanically reconfigured in the lateral direction while maintaining a constant coupling gap. Shearing optical gradient forces are generated when the two cavity centers are laterally displaced. In our experiments, positive and negative lateral shearing optical forces of 0.42 nN and 0.29 nN are observed with different pumping modes. This study may broaden the potential applications of the optical gradient force in nanophotonic devices and benefit the future nanooptoelectromechanical systems.

  3. Birefringence Optical Feedback with a Folded Cavity in HeNe Laser

    International Nuclear Information System (INIS)

    Wu Yun; Tan Yi-Dong

    2013-01-01

    The birefringence optical feedback with a folded cavity in HeNe laser is investigated. A theory model based on the equivalent cavity of the Fabry—Perot interferometer is presented. The phase difference between the two intensities in birefringence feedback is twice the retardation of the wave plate. The phase difference is invariable when the length of the feedback cavity changes. With the adoption of a cube corner prism (CCP) to form a folded cavity, the fringe frequency is doubled, and the resolution of the displacement sensor based on birefringence optical feedback with a folded cavity is improved. A resistance chain of 5-fold subdivision and 4-fold logic subdivision is used as further subdivision. The resolution of λ/80 is obtained eventually; for 632.8 nm HeNe laser it is 7.91 nm. The displacement sensor based on birefringence optical feedback with a folded cavity is simple and of high resolution, large measurement range, low cost, and is of great application potential in industry

  4. Cavity nonlinear optics with layered materials

    Directory of Open Access Journals (Sweden)

    Fryett Taylor

    2017-12-01

    Full Text Available Unprecedented material compatibility and ease of integration, in addition to the unique and diverse optoelectronic properties of layered materials, have generated significant interest in their utilization in nanophotonic devices. While initial nanophotonic experiments with layered materials primarily focused on light sources, modulators, and detectors, recent efforts have included nonlinear optical devices. In this paper, we review the current state of cavity-enhanced nonlinear optics with layered materials. Along with conventional nonlinear optics related to harmonic generation, we report on emerging directions of nonlinear optics, where layered materials can potentially play a significant role.

  5. Mounting system for optical frequency reference cavities

    Science.gov (United States)

    Notcutt, Mark (Inventor); Hall, John L. (Inventor); Ma, Long-Sheng (Inventor)

    2008-01-01

    A technique for reducing the vibration sensitivity of laser-stabilizing optical reference cavities is based upon an improved design and mounting method for the cavity, wherein the cavity is mounted vertically. It is suspended at one plane, around the spacer cylinder, equidistant from the mirror ends of the cavity. The suspension element is a collar of an extremely low thermal expansion coefficient material, which surrounds the spacer cylinder and contacts it uniformly. Once the collar has been properly located, it is cemented in place so that the spacer cylinder is uniformly supported and does not have to be squeezed at all. The collar also includes a number of cavities partially bored into its lower flat surface, around the axial bore. These cavities are support points, into which mounting base pins will be inserted. Hence the collar is supported at a minimum of three points.

  6. Optical re-injection in cavity-enhanced absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Leen, J. Brian, E-mail: b.leen@lgrinc.com; O’Keefe, Anthony [Los Gatos Research, 67 E. Evelyn Avenue, Suite 3, Mountain View, California 94041 (United States)

    2014-09-15

    Non-mode-matched cavity-enhanced absorption spectrometry (e.g., cavity ringdown spectroscopy and integrated cavity output spectroscopy) is commonly used for the ultrasensitive detection of trace gases. These techniques are attractive for their simplicity and robustness, but their performance may be limited by the reflection of light from the front mirror and the resulting low optical transmission. Although this low transmitted power can sometimes be overcome with higher power lasers and lower noise detectors (e.g., in the near-infrared), many regimes exist where the available light intensity or photodetector sensitivity limits instrument performance (e.g., in the mid-infrared). In this article, we describe a method of repeatedly re-injecting light reflected off the front mirror of the optical cavity to boost the cavity's circulating power and deliver more light to the photodetector and thus increase the signal-to-noise ratio of the absorption measurement. We model and experimentally demonstrate the method's performance using off-axis cavity ringdown spectroscopy (OA-CRDS) with a broadly tunable external cavity quantum cascade laser. The power coupled through the cavity to the detector is increased by a factor of 22.5. The cavity loss is measured with a precision of 2 × 10{sup −10} cm{sup −1}/√(Hz;) an increase of 12 times over the standard off-axis configuration without reinjection and comparable to the best reported sensitivities in the mid-infrared. Finally, the re-injected CRDS system is used to measure the spectrum of several volatile organic compounds, demonstrating the improved ability to resolve weakly absorbing spectroscopic features.

  7. Enhancing optical nonreciprocity by an atomic ensemble in two coupled cavities

    Science.gov (United States)

    Song, L. N.; Wang, Z. H.; Li, Yong

    2018-05-01

    We study the optical nonreciprocal propagation in an optical molecule of two coupled cavities with one of them interacting with a two-level atomic ensemble. The effect of increasing the number of atoms on the optical isolation ratio of the system is studied. We demonstrate that the significant nonlinearity supplied by the coupling of the atomic ensemble with the cavity leads to the realization of greatly-enhanced optical nonreciprocity compared with the case of single atom.

  8. Optical cavity-assisted broadband optical transparency of a plasmonic metal film

    International Nuclear Information System (INIS)

    Liu, Zhengqi; Nie, Yiyou; Yuan, Wen; Liu, Xiaoshan; Huang, Shan; Gao, Huogui; Gu, Gang; Liu, Guiqiang; Chen, Jing

    2015-01-01

    We theoretically present a powerful method to achieve a continuous metal film structure with broadband optical transparency via introducing a dielectric Fabry–Pérot (FP) cavity. An incident optical field could be efficiently coupled and confined with the strong localized plasmons by the non-close-packed plasmonic crystal at the input part and could then become re-radiated output via the transmission channel supported by the dielectric cavity. The formed photonic-plasmonic system could therefore make the seamless metal film structure have a superior near-unity transparency (up to 97%) response and a broadband transparent spectrum with bandwidth >245 nm (with transmittance >90%) in the optical regime. The observed optical properties of the proposed structure can be highly tuned via varying the structural parameters. Based on the colloidal assembly method, the proposed plasmonic crystal can be fabricated in a large area. In addition, the achieved optical transparency can be retained in the extremely roughed metal film structure. Thereby, the findings could offer a feasible way to achieve a broadband transparent metal film structure and hold potential applications in transparent electrodes, touch screens and interactive electronics. (paper)

  9. UV plasmonic enhancement through three dimensional nano-cavity antenna array in aluminum

    Science.gov (United States)

    Mao, Jieying; Stevenson, Peter; Montanaric, Danielle; Wang, Yunshan; Shumaker-Parry, Jennifer S.; Harris, Joel M.; Blair, Steve

    2017-08-01

    Metallic nanostructure can enhance fluorescence through excited surface plasmons which increase the local field as well as improve its quantum efficiency. When coupling to cavity resonance with proper gap dimension, gap hot spots can be generated to interact with fluorescence at their excitation/emission region in UV. A 3D nano-cavity antenna array in Aluminum has been conducted to generate local hot spot resonant at fluorescence emission resonance. Giant field enhancement has been achieved through coupling fundamental resonance modes of nanocavity into surface plasmons polaritons (SPPs). In this work, two distinct plasmonic structure of 3D resonant cavity nanoantenna has been studied and its plasmonic response has been scaled down to the UV regime through finite-difference-time-domain (FDTD) method. Two different strategies for antenna fabrication will be conducted to obtain D-coupled Dots-on-Pillar Antenna array (D2PA) through Focus Ion Beam (FIB) and Cap- Hole Pair Antenna array (CHPA) through nanosphere template lithography (NTL). With proper optimization of the structures, D2PA and CHPA square array with 280nm pitch have achieved distinct enhancement at fluorophore emission wavelength 350nm and excitation wavelength 280nm simultaneously. Maximum field enhancement can reach 20 and 65 fold in the gap of D2PA and CHPA when light incident from substrate, which is expected to greatly enhance fluorescent quantum efficiency that will be confirmed in fluorescence lifetime measurement.

  10. Optothermal transport behavior in whispering gallery mode optical cavities

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, Soheil [Ming Hsieh Department of Electrical Engineering-Electrophysics, University of Southern California, Los Angeles, California 90089 (United States); Armani, Andrea M., E-mail: armani@usc.edu [Ming Hsieh Department of Electrical Engineering-Electrophysics, University of Southern California, Los Angeles, California 90089 (United States); Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089 (United States)

    2014-08-04

    Over the past century, whispering gallery mode optical cavities have enabled numerous advances in science and engineering, such as discoveries in quantum mechanics and non-linear optics, as well as the development of optical gyroscopes and add drop filters. One reason for their widespread appeal is their ability to confine light for long periods of time, resulting in high circulating intensities. However, when sufficiently large amounts of optical power are coupled into these cavities, they begin to experience optothermal or photothermal behavior, in which the optical energy is converted into heat. Above the optothermal threshold, the resonance behavior is no longer solely defined by electromagnetics. Previous work has primarily focused on the role of the optothermal coefficient of the material in this instability. However, the physics of this optothermal behavior is significantly more complex. In the present work, we develop a predictive theory based on a generalizable analytical expression in combination with a geometry-specific COMSOL Multiphysics finite element method model. The simulation couples the optical and thermal physics components, accounting for geometry variations as well as the temporal and spatial profile of the optical field. To experimentally verify our theoretical model, the optothermal thresholds of a series of silica toroidal resonant cavities are characterized at different wavelengths (visible through near-infrared) and using different device geometries. The silica toroid offers a particularly rigorous case study for the developed optothermal model because of its complex geometrical structure which provides multiple thermal transport paths.

  11. Optical Material Characterization Using Microdisk Cavities

    Science.gov (United States)

    Michael, Christopher P.

    Since Jack Kilby recorded his "Monolithic Idea" for integrated circuits in 1958, microelectronics companies have invested billions of dollars in developing the silicon material system to increase performance and reduce cost. For decades, the industry has made Moore's Law, concerning cost and transistor density, a self-fulfilling prophecy by integrating technical and material requirements vertically down their supply chains and horizontally across competitors in the market. At recent technology nodes, the unacceptable scaling behavior of copper interconnects has become a major design constraint by increasing latency and power consumption---more than 50% of the power consumed by high speed processors is dissipated by intrachip communications. Optical networks at the chip scale are a potential low-power high-bandwidth replacement for conventional global interconnects, but the lack of efficient on-chip optical sources has remained an outstanding problem despite significant advances in silicon optoelectronics. Many material systems are being researched, but there is no ideal candidate even though the established infrastructure strongly favors a CMOS-compatible solution. This thesis focuses on assessing the optical properties of materials using microdisk cavities with the intention to advance processing techniques and materials relevant to silicon photonics. Low-loss microdisk resonators are chosen because of their simplicity and long optical path lengths. A localized photonic probe is developed and characterized that employs a tapered optical-fiber waveguide, and it is utilized in practical demonstrations to test tightly arranged devices and to help prototype new fabrication methods. A case study in AlxGa1-xAs illustrates how the optical scattering and absorption losses can be obtained from the cavity-waveguide transmission. Finally, single-crystal Er2O3 epitaxially grown on silicon is analyzed in detail as a potential CMOS-compatable gain medium due to its high Er3

  12. Handbook of optical microcavities

    CERN Document Server

    Choi, Anthony H W

    2014-01-01

    An optical cavity confines light within its structure and constitutes an integral part of a laser device. Unlike traditional gas lasers, semiconductor lasers are invariably much smaller in dimensions, making optical confinement more critical than ever. In this book, modern methods that control and manipulate light at the micrometer and nanometer scales by using a variety of cavity geometries and demonstrate optical resonance from ultra-violet (UV) to infra-red (IR) bands across multiple material platforms are explored. The book has a comprehensive collection of chapters that cover a wide range

  13. Laser of optical fiber composed by two coupled cavities: application as optical fiber sensor

    International Nuclear Information System (INIS)

    Vazquez S, R.A.; Kuzin, E.A.; Ibarra E, B.; May A, M.; Shlyagin, M.; Marquez B, I.

    2004-01-01

    We show an optical fiber laser sensor which consist of two cavities coupled and three fiber Bragg gratings. We used one Bragg grating (called reference) and two Bragg gratings (called sensors), which have the lower reflection wavelength. The reference grating with the two sensors grating make two cavities: first one is the internal cavity which has 4230 m of length and the another one is the external cavity which has 4277 m of length. Measuring the laser beating frequency for a resonance cavity and moving the frequency peaks when the another cavity is put in resonance, we prove that the arrangement can be used as a two points sensor for determining the difference of temperature or stress between these two points. (Author)

  14. Acousto-optical interaction of surface acoustic and optical waves in a two-dimensional phoxonic crystal hetero-structure cavity.

    Science.gov (United States)

    Ma, Tian-Xue; Zou, Kui; Wang, Yue-Sheng; Zhang, Chuanzeng; Su, Xiao-Xing

    2014-11-17

    Phoxonic crystal is a promising material for manipulating sound and light simultaneously. In this paper, we theoretically demonstrate the propagation of acoustic and optical waves along the truncated surface of a two-dimensional square-latticed phoxonic crystal. Further, a phoxonic crystal hetero-structure cavity is proposed, which can simultaneously confine surface acoustic and optical waves. The interface motion and photoelastic effects are taken into account in the acousto-optical coupling. The results show obvious shifts in eigenfrequencies of the photonic cavity modes induced by different phononic cavity modes. The symmetry of the phononic cavity modes plays a more important role in the single-phonon exchange process than in the case of the multi-phonon exchange. Under the same deformation, the frequency shift of the photonic transverse electric mode is larger than that of the transverse magnetic mode.

  15. Anisotropic optical feedback of single frequency intra-cavity He–Ne laser

    International Nuclear Information System (INIS)

    Lu-Fei, Zhou; Shu-Lian, Zhang; Yi-Dong, Tan; Wei-Xin, Liu; Bin, Zhang

    2009-01-01

    This paper presents the anisotropic optical feedback of a single frequency intra-cavity He–Ne laser. A novel phenomenon was discovered that the laser output an elliptical polarized frequency instead of the initial linear polarized one. Two intensities with a phase difference were detected, both of which were modulated in the form of cosine wave and a fringe shift corresponds to a λ/2 movement of the feedback mirror. The phase difference can be continuously modulated by the wave plate in the external cavity. Frequency stabilization was used to stabilize the laser frequency so as to enlarge the measuring range and improve the measurement precision. This anisotropic optical feedback system offers a potential displacement measurement technology with the function of subdivision of λ/2 and in-time direction judgment. The three-mirror Fabry–Perot cavity model is used to present the experimental results. Given the lack of need of lasing adjustment, this full intra-cavity laser can significantly improve the simplicity and stability of the optical feedback system. (fluids, plasmas and electric discharges)

  16. Bifurcation structure of an optical ring cavity

    DEFF Research Database (Denmark)

    Kubstrup, C.; Mosekilde, Erik

    1996-01-01

    One- and two-dimensional continuation techniques are applied to determine the basic bifurcation structure for an optical ring cavity with a nonlinear absorbing element (the Ikeda Map). By virtue of the periodic structure of the map, families of similar solutions develop in parameter space. Within...

  17. UV irradiation assisted growth of ZnO nanowires on optical fiber surface

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Bo; Shi, Tielin; Liao, Guanglan; Li, Xiaoping; Huang, Jie; Zhou, Temgyuan; Tang, Zirong, E-mail: zirong@mail.hust.edu.cn

    2017-06-01

    Highlights: • A new fabrication process combined a hydrothermal process with UV irradiation from optical fiber is developed. • The growth of ZnO nanowires is efficient in the utilization of UV light. • A novel hybrid structure which integrates ZnO nanowires on optical fiber surface is synthesized. • The UV assisted growth of ZnO nanowires shows preferred orientation and better quality. • A mechanism of growing ZnO nanowires under UV irradiation is proposed. - Abstract: In this paper, a novel approach was developed for the enhanced growth of ZnO nanowires on optical fiber surface. The method combined a hydrothermal process with the efficient UV irradiation from the fiber core, and the effects of UV irradiation on the growth behavior of ZnO nanowires were investigated. The results show that UV irradiation had great effects on the preferred growth orientation and the quality of the ZnO nanowires. The crystallization velocity along the c-axis would increase rapidly with the increase of the irradiation power, while the growth process in the lateral direction was marginally affected by the irradiation. The structure of ZnO nanowires also shows less oxygen vacancy with UV irradiation of higher power. The developed approach is applicable for the efficient growth of nanowires on the fiber surface, and the ZnO nanowires/optical fiber hybrid structures have great potentials for a wide variety of applications such as optical fiber sensors and probes.

  18. Automated optical inspection and image analysis of superconducting radio-frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wenskat, Marc

    2017-04-15

    The inner surface of superconducting cavities plays a crucial role to achieve highest accelerating fields and low losses. For an investigation of this inner surface of more than 100 cavities within the cavity fabrication for the European XFEL and the ILC HiGrade Research Project, an optical inspection robot OBACHT was constructed. To analyze up to 2325 images per cavity, an image processing and analysis code was developed and new variables to describe the cavity surface were obtained. The accuracy of this code is up to 97% and the PPV 99% within the resolution of 15.63 μm. The optical obtained surface roughness is in agreement with standard profilometric methods. The image analysis algorithm identified and quantified vendor specific fabrication properties as the electron beam welding speed and the different surface roughness due to the different chemical treatments. In addition, a correlation of ρ=-0.93 with a significance of 6σ between an obtained surface variable and the maximal accelerating field was found.

  19. Automated optical inspection and image analysis of superconducting radio-frequency cavities

    International Nuclear Information System (INIS)

    Wenskat, Marc

    2017-04-01

    The inner surface of superconducting cavities plays a crucial role to achieve highest accelerating fields and low losses. For an investigation of this inner surface of more than 100 cavities within the cavity fabrication for the European XFEL and the ILC HiGrade Research Project, an optical inspection robot OBACHT was constructed. To analyze up to 2325 images per cavity, an image processing and analysis code was developed and new variables to describe the cavity surface were obtained. The accuracy of this code is up to 97% and the PPV 99% within the resolution of 15.63 μm. The optical obtained surface roughness is in agreement with standard profilometric methods. The image analysis algorithm identified and quantified vendor specific fabrication properties as the electron beam welding speed and the different surface roughness due to the different chemical treatments. In addition, a correlation of ρ=-0.93 with a significance of 6σ between an obtained surface variable and the maximal accelerating field was found.

  20. Electromagnetic Wave Chaos in Gradient Refractive Index Optical Cavities

    International Nuclear Information System (INIS)

    Wilkinson, P. B.; Fromhold, T. M.; Taylor, R. P.; Micolich, A. P.

    2001-01-01

    Electromagnetic wave chaos is investigated using two-dimensional optical cavities formed in a cylindrical gradient refractive index lens with reflective surfaces. When the planar ends of the lens are cut at an angle to its axis, the geometrical ray paths are chaotic. In this regime, the electromagnetic mode spectrum of the cavity is modulated by both real and ghost periodic ray paths, which also 'scar' the electric field intensity distributions of many modes. When the cavity is coupled to waveguides, the eigenmodes generate complex series of resonant peaks in the electromagnetic transmission spectrum

  1. Deterministically entangling multiple remote quantum memories inside an optical cavity

    Science.gov (United States)

    Yan, Zhihui; Liu, Yanhong; Yan, Jieli; Jia, Xiaojun

    2018-01-01

    Quantum memory for the nonclassical state of light and entanglement among multiple remote quantum nodes hold promise for a large-scale quantum network, however, continuous-variable (CV) memory efficiency and entangled degree are limited due to imperfect implementation. Here we propose a scheme to deterministically entangle multiple distant atomic ensembles based on CV cavity-enhanced quantum memory. The memory efficiency can be improved with the help of cavity-enhanced electromagnetically induced transparency dynamics. A high degree of entanglement among multiple atomic ensembles can be obtained by mapping the quantum state from multiple entangled optical modes into a collection of atomic spin waves inside optical cavities. Besides being of interest in terms of unconditional entanglement among multiple macroscopic objects, our scheme paves the way towards the practical application of quantum networks.

  2. Different optical properties in different periodic slot cavity geometrical morphologies

    Science.gov (United States)

    Zhou, Jing; Shen, Meng; Du, Lan; Deng, Caisong; Ni, Haibin; Wang, Ming

    2016-09-01

    In this paper, optical properties of two-dimensional periodic annular slot cavity arrays in hexagonal close-packing on a silica substrate are theoretically characterized by finite difference time domain (FDTD) simulation method. By simulating reflectance spectra, electric field distribution, and charge distribution, we confirm that multiple cylindrical surface plasmon resonances can be excited in annular inclined slot cavities by linearly polarized light, in which the four reflectance dips are attributed to Fabry-Perot cavity resonances in the coaxial cavity. A coaxial waveguide mode TE11 will exist in these annular cavities, and the wavelengths of these reflectance dips are effectively tailored by changing the geometrical pattern of slot cavity and the dielectric materials filled in the cavities. These resonant wavelengths are localized in annular cavities with large electric field enhancement and dissipate gradually due to metal loss. The formation of an absorption peak can be explained from the aspect of phase matching conditions. We observed that the proposed structure can be tuned over the broad spectral range of 600-4000 nm by changing the outer and inner radii of the annular gaps, gap surface topography. Meanwhile, different lengths of the cavity may cause the shift of resonance dips. Also, we study the field enhancement at different vertical locations of the slit. In addition, dielectric materials filling in the annular gaps will result in a shift of the resonance wavelengths, which make the annular cavities good candidates for refractive index sensors. The refractive index sensitivity of annular cavities can also be tuned by the geometry size and the media around the cavity. Annular cavities with novel applications can be implied as surface enhanced Raman spectra substrates, refractive index sensors, nano-lasers, and optical trappers. Project supported by the National Natural Science Foundation of China (Grant No. 61178044), the Natural Science Foundation

  3. All-dielectric resonant cavity-enabled metals with broadband optical transparency

    Science.gov (United States)

    Liu, Zhengqi; Zhang, Houjiao; Liu, Xiaoshan; Pan, Pingping; Liu, Yi; Tang, Li; Liu, Guiqiang

    2017-06-01

    Metal films with broadband optical transparency are desirable in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and infrared detectors. As bare metal is opaque to light, this issue of transparency attracts great scientific interest. In this work, we proposed and demonstrated a feasible and universal approach for achieving broadband optical transparent (BOT) metals by utilizing all-dielectric resonant cavities. Resonant dielectrics provide optical cavity modes and couple strongly with the surface plasmons of the metal film, and therefore produce a broadband near-unity optical transparent window. The relative enhancement factor (EF) of light transmission exceeds 3400% in comparison with that of pure metal film. Moreover, the transparent metal motif can be realized by other common metals including gold (Au), silver (Ag) and copper (Cu). These optical features together with the fully retained electric and mechanical properties of a natural metal suggest that it will have wide applications in optoelectronic devices.

  4. 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.

  5. Fiber Optic Based Thermometry System for Superconducting RF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Kochergin, Vladimir [Microxact Inc.

    2013-05-06

    Thermometry is recognized as the best technique to identify and characterize losses in SRF cavities. The most widely used and reliable apparatus for temperature mapping at cryogenic temperatures is based on carbon resistors (RTDs). The use of this technology on multi-cell cavities is inconvenient due to the very large number of sensors required to obtain sufficient spatial resolution. Recent developments make feasible the use of multiplexible fiber optic sensors for highly distributed temperature measurements. However, sensitivity of multiplexible cryogenic temperature sensors was found extending only to 12K at best and thus was not sufficient for SRF cavity thermometry. During the course of the project the team of MicroXact, JLab and Virginia Tech developed and demonstrated the multiplexible fiber optic sensor with adequate response below 20K. The demonstrated temperature resolution is by at least a factor of 60 better than that of the best multiplexible fiber optic temperature sensors reported to date. The clear path toward at least 10times better temperature resolution is shown. The first to date temperature distribution measurements with ~2.5mm spatial resolution was done with fiber optic sensors at 2K to4K temperatures. The repeatability and accuracy of the sensors were verified only at 183K, but at this temperature both parameters significantly exceeded the state of the art. The results of this work are expected to find a wide range of applications, since the results are enabling the whole new testing capabilities, not accessible before.

  6. Automated optical inspection and image analysis of superconducting radio-frequency cavities

    Science.gov (United States)

    Wenskat, M.

    2017-05-01

    The inner surface of superconducting cavities plays a crucial role to achieve highest accelerating fields and low losses. For an investigation of this inner surface of more than 100 cavities within the cavity fabrication for the European XFEL and the ILC HiGrade Research Project, an optical inspection robot OBACHT was constructed. To analyze up to 2325 images per cavity, an image processing and analysis code was developed and new variables to describe the cavity surface were obtained. The accuracy of this code is up to 97 % and the positive predictive value (PPV) 99 % within the resolution of 15.63 μm. The optical obtained surface roughness is in agreement with standard profilometric methods. The image analysis algorithm identified and quantified vendor specific fabrication properties as the electron beam welding speed and the different surface roughness due to the different chemical treatments. In addition, a correlation of ρ = -0.93 with a significance of 6 σ between an obtained surface variable and the maximal accelerating field was found.

  7. Active material, optical mode and cavity impact on nanoscale electro-optic modulation performance

    Science.gov (United States)

    Amin, Rubab; Suer, Can; Ma, Zhizhen; Sarpkaya, Ibrahim; Khurgin, Jacob B.; Agarwal, Ritesh; Sorger, Volker J.

    2017-10-01

    Electro-optic modulation is a key function in optical data communication and possible future optical compute engines. The performance of modulators intricately depends on the interaction between the actively modulated material and the propagating waveguide mode. While a variety of high-performance modulators have been demonstrated, no comprehensive picture of what factors are most responsible for high performance has emerged so far. Here we report the first systematic and comprehensive analytical and computational investigation for high-performance compact on-chip electro-optic modulators by considering emerging active materials, model considerations and cavity feedback at the nanoscale. We discover that the delicate interplay between the material characteristics and the optical mode properties plays a key role in defining the modulator performance. Based on physical tradeoffs between index modulation, loss, optical confinement factors and slow-light effects, we find that there exist combinations of bias, material and optical mode that yield efficient phase or amplitude modulation with acceptable insertion loss. Furthermore, we show how material properties in the epsilon near zero regime enable reduction of length by as much as by 15 times. Lastly, we introduce and apply a cavity-based electro-optic modulator figure of merit, Δλ/Δα, relating obtainable resonance tuning via phase shifting relative to the incurred losses due to the fundamental Kramers-Kronig relations suggesting optimized device operating regions with optimized modulation-to-loss tradeoffs. This work paves the way for a holistic design rule of electro-optic modulators for high-density on-chip integration.

  8. Optical system for UV-laser technological equipment

    Science.gov (United States)

    Fedosov, Yuri V.; Romanova, Galina E.; Afanasev, Maxim Ya.

    2017-09-01

    Recently there has been an intensive development of intelligent industrial equipment that is highly automated and can be rapidly adjusted for certain details. This equipment can be robotics systems, automatic wrappers and markers, CNC machines and 3D printers. The work equipment considered is the system for selective curing of photopolymers using a UV-laser and UV-radiation in such equipment that leads to additional technical difficulties. In many cases for transporting the radiation from the laser to the point processed, a multi-mirror system is used: however, such systems are usually difficult to adjust. Additionally, such multi-mirror systems are usually used as a part of the equipment for laser cutting of metals using high-power IR-lasers. For the UV-lasers, using many mirrors leads to crucial radiation losses because of many reflections. Therefore, during the development of the optical system for technological equipment using UV-laser we need to solve two main problems: to transfer the radiation for the working point with minimum losses and to include the system for controlling/handling the radiation spot position. We introduce a system for working with UV-lasers with 450mW of power and a wavelength of 0.45 μm based on a fiber system. In our modelling and design, we achieve spot sizes of about 300 μm, and the designed optical and mechanical systems (prototypes) were manufactured and assembled. In this paper, we present the layout of the technological unit, the results of the theoretical modelling of some parts of the system and some experimental results.

  9. Optical surface properties and their RF limitations of European XFEL cavities

    Science.gov (United States)

    Wenskat, Marc

    2017-10-01

    The inner surface of superconducting cavities plays a crucial role to achieve highest accelerating fields and low losses. The industrial fabrication of cavities for the European X-ray Free Electron Laser and the International Linear Collider HiGrade Research Project allowed for an investigation of this interplay. For the serial inspection of the inner surface, the optical inspection robot ’optical bench for automated cavity inspection with high resolution on short timescales’ OBACHT was constructed and to analyze the large amount of data, represented in the images of the inner surface, an image processing and analysis code was developed and new variables to describe the cavity surface were obtained. This quantitative analysis identified vendor-specific surface properties which allow the performance of quality control and assurance during production. In addition, a strong negative correlation of ρ =-0.93 with a significance of 6 σ of the integrated grain boundary area \\sum {A} versus the maximal achievable accelerating field {{E}}{acc,\\max } has been found.

  10. The system of enclosed optical cavities as a tool for laser photons storing

    International Nuclear Information System (INIS)

    Androsov, V.P.; Karnaukhov, I.M.; Telegin, Yu.N.

    2004-01-01

    The calculation of the system consisting of two optical cavities enclosed one into another is performed in the plane-wave approximation. It is shown that under definite conditions one can obtain an enhancement of the electromagnetic field in the internal cavity as compared to the case of direct excitation of the cavity with an electromagnetic wave of the same amplitude. The comparative analysis of these two approaches is carried out. We suppose to apply the proposed system with moderate-reflectivity mirrors (R=0.99) for accumulating laser photons in the optical cavity of the X-ray source LESR-N100 based on Compton scattering of the laser beam on relativistic electrons stored in the ring

  11. Entangling optical and microwave cavity modes by means of a nanomechanical resonator

    Energy Technology Data Exchange (ETDEWEB)

    Barzanjeh, Sh. [Department of Physics, Faculty of Science, University of Isfahan, Hezar Jerib, 81746-73441 Isfahan (Iran, Islamic Republic of); School of Science and Technology, Physics Division, Universita di Camerino, I-62032 Camerino, Macerata (Italy); Vitali, D.; Tombesi, P. [School of Science and Technology, Physics Division, Universita di Camerino, I-62032 Camerino, Macerata (Italy); Milburn, G. J. [Centre for Engineered Quantum Systems, School of Physical Sciences, University of Queensland, Saint Lucia, Queensland 4072 (Australia)

    2011-10-15

    We propose a scheme that is able to generate stationary continuous-variable entanglement between an optical and a microwave cavity mode by means of their common interaction with a nanomechanical resonator. We show that when both cavities are intensely driven, one can generate bipartite entanglement between any pair of the tripartite system, and that, due to entanglement sharing, optical-microwave entanglement is efficiently generated at the expense of microwave-mechanical and optomechanical entanglement.

  12. Entangling optical and microwave cavity modes by means of a nanomechanical resonator

    International Nuclear Information System (INIS)

    Barzanjeh, Sh.; Vitali, D.; Tombesi, P.; Milburn, G. J.

    2011-01-01

    We propose a scheme that is able to generate stationary continuous-variable entanglement between an optical and a microwave cavity mode by means of their common interaction with a nanomechanical resonator. We show that when both cavities are intensely driven, one can generate bipartite entanglement between any pair of the tripartite system, and that, due to entanglement sharing, optical-microwave entanglement is efficiently generated at the expense of microwave-mechanical and optomechanical entanglement.

  13. Cavity assisted measurements of heat and work in optical lattices

    Directory of Open Access Journals (Sweden)

    Louis Villa

    2018-01-01

    Full Text Available We propose a method to experimentally measure the internal energy of a system of ultracold atoms trapped in optical lattices by coupling them to the fields of two optical cavities. We show that the tunnelling and self-interaction terms of the one-dimensional Bose-Hubbard Hamiltonian can be mapped to the field and photon number of each cavity, respectively. We compare the energy estimated using this method with numerical results obtained using the density matrix renormalisation group algorithm. Our method can be employed for the assessment of power and efficiency of thermal machines whose working substance is a strongly correlated many-body system.

  14. Optical/UV-to-X-Ray Echoes from the Tidal Disruption Flare ASASSN-14li

    Energy Technology Data Exchange (ETDEWEB)

    Pasham, Dheeraj R.; Sadowski, Aleksander [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cenko, S. Bradley; Cannizzo, John K. [NASA’s Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Guillochon, James [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Stone, Nicholas C. [Columbia University, New York, NY 10027 (United States); Velzen, Sjoert van [The Johns Hopkins University, Baltimore, MD 21218 (United States)

    2017-03-10

    We carried out the first multi-wavelength (optical/UV and X-ray) photometric reverberation mapping of a tidal disruption flare (TDF) ASASSN-14li. We find that its X-ray variations are correlated with and lag the optical/UV fluctuations by 32 ± 4 days. Based on the direction and the magnitude of the X-ray time lag, we rule out X-ray reprocessing and direct emission from a standard circular thin disk as the dominant source of its optical/UV emission. The lag magnitude also rules out an AGN disk-driven instability as the origin of ASASSN-14li and thus strongly supports the tidal disruption picture for this event and similar objects. We suggest that the majority of the optical/UV emission likely originates from debris stream self-interactions. Perturbations at the self-interaction sites produce optical/UV variability and travel down to the black hole where they modulate the X-rays. The time lag between the optical/UV and the X-rays variations thus correspond to the time taken by these fluctuations to travel from the self-interaction site to close to the black hole. We further discuss these time lags within the context of the three variants of the self-interaction model. High-cadence monitoring observations of future TDFs will be sensitive enough to detect these echoes and would allow us to establish the origin of optical/UV emission in TDFs in general.

  15. Optical/UV-to-X-Ray Echoes from the Tidal Disruption Flare ASASSN-14li

    International Nuclear Information System (INIS)

    Pasham, Dheeraj R.; Sadowski, Aleksander; Cenko, S. Bradley; Cannizzo, John K.; Guillochon, James; Stone, Nicholas C.; Velzen, Sjoert van

    2017-01-01

    We carried out the first multi-wavelength (optical/UV and X-ray) photometric reverberation mapping of a tidal disruption flare (TDF) ASASSN-14li. We find that its X-ray variations are correlated with and lag the optical/UV fluctuations by 32 ± 4 days. Based on the direction and the magnitude of the X-ray time lag, we rule out X-ray reprocessing and direct emission from a standard circular thin disk as the dominant source of its optical/UV emission. The lag magnitude also rules out an AGN disk-driven instability as the origin of ASASSN-14li and thus strongly supports the tidal disruption picture for this event and similar objects. We suggest that the majority of the optical/UV emission likely originates from debris stream self-interactions. Perturbations at the self-interaction sites produce optical/UV variability and travel down to the black hole where they modulate the X-rays. The time lag between the optical/UV and the X-rays variations thus correspond to the time taken by these fluctuations to travel from the self-interaction site to close to the black hole. We further discuss these time lags within the context of the three variants of the self-interaction model. High-cadence monitoring observations of future TDFs will be sensitive enough to detect these echoes and would allow us to establish the origin of optical/UV emission in TDFs in general.

  16. Storage of laser pulses in a Fabry-Perot optical cavity for high flux x-ray

    International Nuclear Information System (INIS)

    Takezawa, K.; Honda, Y.; Sasao, N.; Araki, S.; Higashi, Y.; Taniguchi, T.; Urakawa, J.; Nomura, M.; Sakai, H.

    2004-01-01

    We have a plan to produce a high flux x-ray for medical use by using a Fabry-Perot optical cavity in which the lower pulses from a mode-locked laser are stored and enhanced. In this plan, the X-ray is produced from the Compton scattering of electrons in a storage ring with the laser light in the optical cavity. In order to increase X-ray flux, high power laser light is necessary. We show the enhancement of the laser power from the model locked laser with a Fabry-Perot optical cavity. (author)

  17. Mid-Ir Cavity Ring-Down Spectrometer for Biological Trace Nitric Oxide Detection

    Science.gov (United States)

    Kan, Vincent; Ragab, Ahemd; Stsiapura, Vitali; Lehmann, Kevin K.; Gaston, Benjamin M.

    2011-06-01

    S-nitrosothiols have received much attention in biochemistry and medicine as donors of nitrosonium ion (NO^+) and nitric oxide (NO) - physiologically active molecules involved in vasodilation and signal transduction. Determination of S-nitrosothiols content in cells and tissues is of great importance for fundamental research and medical applications. We will report on our ongoing development of a instrument to measure trace levels of nitric oxide gas (NO), released from S-nitrosothiols after exposure to UV light (340 nm) or reaction with L-Cysteine+CuCl mixture. The instrument uses the method of cavity ring-down spectroscopy, probing rotationally resolved lines in the vibrational fundamental transition near 5.2 μm. The laser source is a continuous-wave, room temperature external cavity quantum cascade laser. An acousto-optic modulator is used to abruptly turn off the optical power incident on the cavity when the laser and cavity pass through resonance.

  18. High stable electro-optical cavity-dumped Nd:YAG laser

    International Nuclear Information System (INIS)

    Ma, Y F; Yu, X; Zhang, J W; Li, H

    2012-01-01

    In this paper, an electro-optical cavity-dumped 10 Hz Nd:Y 3 Al 5 O 12 (Nd:YAG) laser was demonstrated. We designed an optimized high stable concavo-convex cavity according to the thermal-insensitive theory that the cavity could be deep stable and be insensitive to the change of thermal lens of laser crystal when g 1 *g 2 = 1/2. The output pulse width was constant at 6.0±0.1 ns. The maximum output energy was 40 mJ. The laser had outstanding stability of output characteristics. The fluctuations of average output energy and divergence angle within 8 cycles were 1.24% and 0.06 mrad, respectively

  19. Plasma-assisted cleaning of extreme UV optics

    NARCIS (Netherlands)

    Dolgov, Alexandr Alexeevich

    2018-01-01

    Plasma-assisted cleaning of extreme UV optics EUV-induced surface plasma chemistry of photo-active agents The next generation of photolithography, extreme ultraviolet (EUV) lithography, makes use of 13.5 nm radiation. The ionizing photon flux, and vacuum requirements create a challenging operating

  20. Dual-resonances approach to broadband cavity-assisted optical signal processing beyond the carrier relaxation rate

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Kristensen, Philip Trøst; Mørk, Jesper

    2014-01-01

    We propose and analyze a differential control scheme for cavity-enhanced optical signal processing devices based on carrier nonlinearities. The scheme relies on two optical cavities to increase the bandwidth beyond the limit given by the slowest carrier relaxation rate of the medium. Practical...

  1. Development of an optical inspection bench for the inspection of internal surfaces of 650 MHz SCRF cavities

    International Nuclear Information System (INIS)

    Kokil, S.V.; Kane, G.V.; Raghavendra, S.; Chauhan, S.K.; Rajpoot, D.S.; Oraon, B.; Om Prakash; Joshi, S.C.

    2015-01-01

    An optical inspection system has been developed for inspection of internal surfaces of 650 MHz superconducting RF cavities. The cavity parts are welded either using Electron Beam or Laser Beam Welding for making a good quality of weld joints. Surface defects like pits, scratches, welding spatters etc. on the internal surface of the cavity deteriorates cavity performance. Surface quality of the cavity equator joint plays an important role in the cavity performance. To study the quality of equator surface, the inspection bench offers high resolution images with a linear resolution of 45 m/pixel at a distance of ∼200 mm. The bench comprises of two major sub-systems, optical imaging system and cavity positioning system. A digital camera and multi coloured illumination system is used to obtain high resolution images. The camera is mounted inside a long cylindrical tube. The cylindrical tube can be inserted into a SCRF cavity. The length of the cylinder is long enough to inspect five-cell 650 MHz SCRF cavity. The cavity is placed on a set of PTFE rollers, which are mounted on a trolley. The cavity can be moved linearly with the help of ball screw-servomotor mechanism. The camera along with cylindrical tube can be rotated around its axis with a stepper motor to scan the cavity's internal surface. The paper presents the details about the optical inspection bench and optical inspection results. (author)

  2. Regularized linearization for quantum nonlinear optical cavities: application to degenerate optical parametric oscillators.

    Science.gov (United States)

    Navarrete-Benlloch, Carlos; Roldán, Eugenio; Chang, Yue; Shi, Tao

    2014-10-06

    Nonlinear optical cavities are crucial both in classical and quantum optics; in particular, nowadays optical parametric oscillators are one of the most versatile and tunable sources of coherent light, as well as the sources of the highest quality quantum-correlated light in the continuous variable regime. Being nonlinear systems, they can be driven through critical points in which a solution ceases to exist in favour of a new one, and it is close to these points where quantum correlations are the strongest. The simplest description of such systems consists in writing the quantum fields as the classical part plus some quantum fluctuations, linearizing then the dynamical equations with respect to the latter; however, such an approach breaks down close to critical points, where it provides unphysical predictions such as infinite photon numbers. On the other hand, techniques going beyond the simple linear description become too complicated especially regarding the evaluation of two-time correlators, which are of major importance to compute observables outside the cavity. In this article we provide a regularized linear description of nonlinear cavities, that is, a linearization procedure yielding physical results, taking the degenerate optical parametric oscillator as the guiding example. The method, which we call self-consistent linearization, is shown to be equivalent to a general Gaussian ansatz for the state of the system, and we compare its predictions with those obtained with available exact (or quasi-exact) methods. Apart from its operational value, we believe that our work is valuable also from a fundamental point of view, especially in connection to the question of how far linearized or Gaussian theories can be pushed to describe nonlinear dissipative systems which have access to non-Gaussian states.

  3. Offline estimation of decay time for an optical cavity with a low pass filter cavity model.

    Science.gov (United States)

    Kallapur, Abhijit G; Boyson, Toby K; Petersen, Ian R; Harb, Charles C

    2012-08-01

    This Letter presents offline estimation results for the decay-time constant for an experimental Fabry-Perot optical cavity for cavity ring-down spectroscopy (CRDS). The cavity dynamics are modeled in terms of a low pass filter (LPF) with unity DC gain. This model is used by an extended Kalman filter (EKF) along with the recorded light intensity at the output of the cavity in order to estimate the decay-time constant. The estimation results using the LPF cavity model are compared to those obtained using the quadrature model for the cavity presented in previous work by Kallapur et al. The estimation process derived using the LPF model comprises two states as opposed to three states in the quadrature model. When considering the EKF, this means propagating two states and a (2×2) covariance matrix using the LPF model, as opposed to propagating three states and a (3×3) covariance matrix using the quadrature model. This gives the former model a computational advantage over the latter and leads to faster execution times for the corresponding EKF. It is shown in this Letter that the LPF model for the cavity with two filter states is computationally more efficient, converges faster, and is hence a more suitable method than the three-state quadrature model presented in previous work for real-time estimation of the decay-time constant for the cavity.

  4. Piezoelectric deformable mirror for intra-cavity laser adaptive optics.

    CSIR Research Space (South Africa)

    Long, CS

    2008-03-01

    Full Text Available This paper describes the development of a deformable mirror to be used in conjunction with diffractive optical elements inside a laser cavity. A prototype piezoelectric unimorph adaptive mirror was developed to correct for time dependent phase...

  5. Optical and UV-Aging Properties of LDH-Modified Bitumen

    Directory of Open Access Journals (Sweden)

    Xing Liu

    2015-07-01

    Full Text Available Layered double hydroxides (LDHs are an ultraviolet-light (UV resistant material. In this study, LDHs were used to modify bitumen. The optical and UV aging properties of LDHs modified bitumen were investigated. Firstly, the thin films of bitumen, with and without LDHs, were prepared. By using the UV-Vis spectrophotometer, absorbance, reflectance, and transmittance of bituminous thin film were evaluated. The morphology of LDHs-modified bitumen was observed by using fluorescence microscopy (FM. Finally, the aging resistance of LDH-modified bitumen was investigated by using the UV-aging oven. Results indicated that the LDHs, especially with 5 wt % in the bitumen, can effectively absorb and reflect the UV light and improve the UV-aging resistance of bitumen. This implied that the addition of LDHs into bitumen had the potential to prolong the service life of asphalt pavement.

  6. Controllable optical bistability in a three-mode optomechanical system with atom-cavity-mirror couplings

    Science.gov (United States)

    Chen, Bin; Wang, Xiao-Fang; Yan, Jia-Kai; Zhu, Xiao-Fei; Jiang, Cheng

    2018-01-01

    We theoretically investigate the optical bistable behavior in a three-mode optomechanical system with atom-cavity-mirror couplings. The effects of the cavity-pump detuning and the pump power on the bistable behavior are discussed detailedly, the impacts of the atom-pump detuning and the atom-cavity coupling strength on the bistability of the system are also explored, and the influences of the cavity-resonator coupling strength and the cavity decay rate are also taken into consideration. The numerical results demonstrate that by tuning these parameters the bistable behavior of the system can be freely switched on or off, and the threshold of the pump power for the bistability as well as the bistable region width can also be effectively controlled. These results can find potential applications in optical bistable switch in the quantum information processing.

  7. UV Radiation Detection Using Optical Sensor Based on Eu3+ Doped PMMA

    Directory of Open Access Journals (Sweden)

    Miluski Piotr

    2016-12-01

    Full Text Available Progress in UV treatment applications requires new compact and sensor constructions. In the paper a hybrid (organic-inorganic rare-earth-based polymeric UV sensor construction is proposed. The efficient luminescence of poly(methyl methacrylate (PMMA matrix doped by europium was used for testing the optical sensor (optrode construction. The europium complex assures effective luminescence in the visible range with well determined multi-peak spectrum emission enabling construction of the optrode. The fabricated UV optical fibre sensor was used for determination of Nd:YAG laser intensity measurements at the third harmonic (355 nm in the radiation power range 5.0-34.0 mW. The multi-peak luminescence spectrum was used for optimization of the measurement formula. The composition of luminescent peak intensity enables to increase the slope of sensitivity up to −2.8 mW-1. The obtained results and advantages of the optical fibre construction enable to apply it in numerous UV detection systems.

  8. UV Written 2x8 Optical Power Splitter for FTTH Applications

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2006-01-01

    Silica based integrated optical 2x8 power splitters are reported for the first time using UV-writing waveguide fabrication technology. High performance, compactness and low production costs make these components well suited for deployment in FTTH networks.......Silica based integrated optical 2x8 power splitters are reported for the first time using UV-writing waveguide fabrication technology. High performance, compactness and low production costs make these components well suited for deployment in FTTH networks....

  9. Adiabatic transfer of energy fluctuations between membranes inside an optical cavity

    Science.gov (United States)

    Garg, Devender; Chauhan, Anil K.; Biswas, Asoka

    2017-08-01

    A scheme is presented for the adiabatic transfer of average fluctuations in the phonon number between two membranes in an optical cavity. We show that by driving the cavity modes with external time-delayed pulses, one can obtain an effect analogous to stimulated Raman adiabatic passage in the atomic systems. The adiabatic transfer of fluctuations from one membrane to the other is attained through a "dark" mode, which is robust against decay of the mediating cavity mode. The results are supported with analytical and numerical calculations with experimentally feasible parameters.

  10. High reflectivity YDH/SiO2 distributed Bragg reflector for UV-C wavelength regime

    KAUST Repository

    Alias, Mohd Sharizal

    2018-02-15

    A distributed Bragg reflector (DBR) composed of Y2O3-doped HfO2 (YDH)/SiO2 layers with high reflectivity spectrum centered at a wavelength of ~240 nm is deposited using radio-frequency magnetron sputtering. Before the DBR deposition, optical properties for a single layer of YDH, SiO2, and HfO2 thin films were studied using spectroscopic ellipsometry and spectrophotometry. To investigate the performance of YDH as a material for the high refractive index layer in the DBR, a comparison of its optical properties was made with HfO2 thin films. Due to larger optical bandgap, the YDH thin films demonstrated higher transparency, lower extinction coefficient, and lower absorption coefficient in the UV-C regime (especially for wavelengths below 250 nm) compared to the HfO2 thin films. The deposited YDH/SiO2 DBR consisting of 15 periods achieved a reflectivity higher than 99.9% at the wavelength of ~240 nm with a stopband of ~50 nm. The high reflectivity and broad stopband of YDH/SiO2 DBRs will enable further advancement of various photonic devices such as vertical-cavity surface-emitting lasers, resonant-cavity light-emitting diodes, and resonant-cavity photodetectors operating in the UV-C wavelength regime.

  11. Self-cavity lasing in optically pumped single crystals of p-sexiphenyl

    International Nuclear Information System (INIS)

    Yanagi, Hisao; Tamura, Kenji; Sasaki, Fumio

    2016-01-01

    Organic single-crystal self-cavities are prepared by solution growth of p-sexiphenyl (p-6P). Based on Fabry-Pérot feedback inside a quasi-lozenge-shaped platelet crystal, edge-emitting laser is obtained under optical pumping. The multimode lasing band appears at the 0-1 or 0-2 vibronic progressions depending on the excitation conditions which affect the self-absorption effect. Cavity-size dependence of amplified spontaneous emission (ASE) is investigated with laser-etched single crystals of p-6P. As the cavity length of square-shaped crystal is reduced from 100 to 10 μm, ASE threshold fluence is decreased probably due to size-dependent light confinement in the crystal cavity.

  12. Scanning near-field optical microscopy of quantum dots in photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Skacel, Matthias; Fiore, Andrea [COBRA Research Institute, Technical University Eindhoven, Den Dolech 2, 5600 MB Eindhoven (Netherlands); Prancardi, Marco; Gerardino, Annamaria [Institute of Photonics and Nanotechnology, CNR, via del Cineto Romano 42, 00156 Roma (Italy); Alloing, Blandine; Li Lianhe, E-mail: m.s.skacel@tue.n [Institute of Photonics and Quantum Electronics, EPFL, CH-1015 Lausanne (Switzerland)

    2010-09-01

    Nanophotonic devices are of major interest for research and future quantum communication applications. Due to their nanometer feature size the resolution limit of far-field microscopy poses a limitation on the characterization of their optical properties. A method to overcome the resolution limit is the Scanning Near-Field Optical Microscope (SNOM). By approaching a fiber tip into the close vicinity of the sample the optical emission in the near-field regime is collected. This way of collecting the light is not affected by the diffraction limit. We employ a low temperature SNOM to investigate the photoluminescence of InAs QDs emitting at 1300nm wavelength embedded in photonic crystal cavities. At each location of an image scan the tip is stopped and a spectrum is acquired. We then plot maps of the photoluminescence for each wavelength. With this instrument it is now possible to directly observe the coupling of QDs to photonic crystal cavities both spectrally and spatially. We show first results of photoluminescence mapping of InAs QDs in photonic crystal cavities.

  13. Cold atoms in optical cavities and lattices

    International Nuclear Information System (INIS)

    Horak, P.

    1996-11-01

    The thesis is organized in three chapters covering different aspects of the interaction of atoms and light in the framework of theoretical quantum optics. In chapter 1 a special case of a microscopic laser where one or two atoms interact with several quantized cavity modes is discussed. In particular I investigate the properties of the light field created in one of the cavity modes. It is shown that a single-atom model already predicts average photon numbers in agreement with a semiclassical many-atom theory. The two-atom model exhibits additional collective features, such as superradiance and subradiance. In chapter 2 effects of the photon recoil on cold atoms in the limit of long-lived atomic transitions are investigated. First, I demonstrate that, in principle, relying on this scheme, a continuous-wave laser in the ultraviolet frequency domain could be established. Second, the splitting of an atomic beam into two coherent subbeams is discussed within the same scheme. Such beamsplitters play an important role in high-precision measurements using atomic interferometers. Finally, chapter 3 deals with cooling and trapping of atoms by the interaction with laser light. I discuss the properties and the light scattering of atoms trapped in a new light field configuration, a so-called dark optical superlattice. In principle, such systems allow the trapping of more than one atom in the ground state of a single optical potential well. This could give rise to the observation of e.g. atom-atom interactions and quantum statistical effects. (author)

  14. Quantum phases of spinful Fermi gases in optical cavities

    Science.gov (United States)

    Colella, E.; Citro, R.; Barsanti, M.; Rossini, D.; Chiofalo, M.-L.

    2018-04-01

    We explore the quantum phases emerging from the interplay between spin and motional degrees of freedom of a one-dimensional quantum fluid of spinful fermionic atoms, effectively interacting via a photon-mediating mechanism with tunable sign and strength g , as it can be realized in present-day experiments with optical cavities. We find the emergence, in the very same system, of spin- and atomic-density wave ordering, accompanied by the occurrence of superfluidity for g >0 , while cavity photons are seen to drive strong correlations at all g values, with fermionic character for g >0 , and bosonic character for g analysis.

  15. Effect of UV-irradiation on sol-gel optical films

    International Nuclear Information System (INIS)

    Yang Fan; Shen Jun; Zhou Bin; Wu Guangming; Luo Aiyun; Sun Qi

    2005-01-01

    Sol-gel optical films were deposited on K9 glass and silicon wafer substrates by spin-coating method and a high-pressure mercury lamp was used to perform ultraviolet treating to solidify these films and improve their performance. SEM, AFM, IR and ellipsometer were used to characterize the structure and optical properties of the films. Mechanical property of films was measured by pencil hardness-testing device. Laser damage threshold of films was measured by a Q-switched Nd:YAG high power laser with the wave length of 1064 nm and the pulse width of 15 ns. The results show that UV-irradiation can improve the mechanical property and increase the refractive index of the films. Besides, the nodules on the surface of the films can be changed into pits by UV-irradiation process, so the laser damage threshold of sol-gel thin films will be increased. After UV-irradiation the laser damage threshold of single-layer ZrO 2 film reached 50.6 J/cm 2 (1064 nm, 1 ns). It is found that UV-irradiation is an effective method to avoid the infiltrating between the layers, and the degree of homogeneity of the multilayer films can be improved by this way. (authors)

  16. Very high repetition-rate electro-optical cavity-dumped Nd: YVO4 laser with optics and dynamics stabilities

    Science.gov (United States)

    Liu, Xuesong; Shi, Zhaohui; Huang, Yutao; Fan, Zhongwei; Yu, Jin; Zhang, Jing; Hou, Liqun

    2015-02-01

    In this paper, a very high repetition-rate, short-pulse, electro-optical cavity-dumped Nd: YVO4 laser is experimentally and theoretically investigated. The laser performance is optimized from two aspects. Firstly, the laser resonator is designed for a good thermal stability under large pump power fluctuation through optics methods. Secondly, dynamics simulation as well as experiments verifies that cavity dumping at very high repetition rate has better stability than medium/high repetition rate. At 30 W, 880 nm pump power, up to 500 kHz, constant 5 ns, stable 1064 nm fundamental-mode laser pulses can be obtained with 10 W average output power.

  17. Cost-effective optical fiber pressure sensor based on intrinsic Fabry-Perot interferometric micro-cavities

    Science.gov (United States)

    Domingues, M. Fátima; Rodriguez, Camilo A.; Martins, Joana; Tavares, Cátia; Marques, Carlos; Alberto, Nélia; André, Paulo; Antunes, Paulo

    2018-05-01

    In this work, a cost-effective procedure to manufacture optical fiber pressure sensors is presented. This has a high relevance for integration in robotic exoskeletons or for gait plantar pressure monitoring within the physical rehabilitation scenarios, among other applications. The sensing elements are based on Fabry-Perot interferometric (FPI) micro-cavities, created from the recycling of optical fibers previously destroyed by the catastrophic fuse effect. To produce the pressure sensors, the fiber containing the FPI micro-cavities was embedded in an epoxy resin cylinder used as pressure transducer and responsible to transfer the pressure applied on its surface to the optical fiber containing the FPI micro-cavity. Before the embedding process, some FPI sensors were also characterized to strain variations. After that, the effect of the encapsulation of the FPI structure into the resin was assessed, from which a slight decrease on the FPI interferogram fringes visibility was verified, indicating a small increase in the micro-cavity length. Up on the sensors characterization, a linear dependence of the wavelength shift with the induced pressure was obtained, which leads to a maximum sensitivity of 59.39 ± 1.7 pm/kPa. Moreover, direct dependence of the pressure sensitivity with the micro-cavity volume and length was found.

  18. Processing of Dielectric Optical Coatings by Nanosecond and Femtosecond UV Laser Ablation

    International Nuclear Information System (INIS)

    Ihlemann, J.; Bekesi, J.; Klein-Wiele, J.H.; Simon, P.

    2008-01-01

    Micro processing of dielectric optical coatings by UV laser ablation is demonstrated. Excimer laser ablation at deep UV wavelengths (248 nm, 193 nm) is used for the patterning of thin oxide films or layer stacks. The layer removal over extended areas as well as sub-μm-structuring is possible. The ablation of SiO2, Al2O3, HfO2, and Ta2O5 layers and layer systems has been investigated. Due to their optical, chemical, and thermal stability, these inorganic film materials are well suited for optical applications, even if UV-transparency is required. Transparent patterned films of SiO2 are produced by patterning a UV-absorbing precursor SiOx suboxide layer and oxidizing it afterwards to SiO2. In contrast to laser ablation of bulk material, in the case of thin films, the layer-layer or layer-substrate boundaries act as predetermined end points, so that precise depth control and a very smooth surface can be achieved. For large area ablation, nanosecond lasers are well suited; for patterning with submicron resolution, femtosecond excimer lasers are applied. Thus the fabrication of optical elements like dielectric masks, pixelated diffractive elements, and gratings can be accomplished.

  19. Development of optical inspection system of L-band SRF cavity

    International Nuclear Information System (INIS)

    Tajima, Yujiro; Iwashita, Yoshihisa; Hayano, Hitoshi

    2008-01-01

    The International Linear Collider (ILC) will require about 15,000 1.3 GHz superconducting radio frequency (SRF) accelerating cavities with high accelerating gradient (>35 MV/m) in its main linac. The high yield (80%) of successful high gradient cavities is necessary. Both of the yield and the accelerating gradient of SRF cavities does not reach the required level at present. We think that the gradient of the SRF cavities is limited by irregularities on the interior surface of the cavities, for example, fine dusts (1μm), balls (100μm) and pits (100μm): electrons emitted from the fine dusts by the tunnel effect are accelerated in the electric field, and consume the stored energy of the cavities (Field Emission). The balls and pits cause a breakdown by a magnetic field enhancement or a thermal current concentration (Thermal Breakdown). To prevent these problems the interior surface are treated by polishing and rinsing. The relation between the surface states and the gradient limitations, however, is still not clarified. To study the relation, we are developing an optical inspection system of the interior surface. (author)

  20. Generation and control of optical frequency combs using cavity electromagnetically induced transparency

    Science.gov (United States)

    Li, Jiahua; Qu, Ye; Yu, Rong; Wu, Ying

    2018-02-01

    We explore theoretically the generation and all-optical control of optical frequency combs (OFCs) in photon transmission based on a combination of single-atom-cavity quantum electrodynamics (CQED) and electromagnetically induced transparency (EIT). Here an external control field is used to form the cavity dark mode of the CQED system. When the strengths of the applied EIT control field are appropriately tuned, enhanced comb generation can be achieved. We discuss the properties of the dark mode and clearly show that the formation of the dark mode enables the efficient generation of OFCs. In our approach, the comb spacing is determined by the beating frequency between the driving pump and seed lasers. Our demonstrated theory may pave the way towards all-optical coherent control of OFCs using a CQED architecture.

  1. Enhancement of acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities by utilizing surface acoustic waves

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Tian-Xue [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Wang, Yue-Sheng, E-mail: yswang@bjtu.edu.cn [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Chuanzeng [Department of Civil Engineering, University of Siegen, D-57068 Siegen (Germany)

    2017-01-30

    A phoxonic crystal is a periodically patterned material that can simultaneously localize optical and acoustic modes. The acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities is investigated numerically. The photons can be well confined in the slot owing to the large electric field discontinuity at the air/dielectric interfaces. Besides, the surface acoustic modes lead to the localization of the phonons near the air-slot. The high overlap of the photonic and phononic cavity modes near the slot results in a significant enhancement of the moving interface effect, and thus strengthens the total acousto-optical interaction. The results of two cavities with different slot widths show that the coupling strength is dependent on the slot width. It is expected to achieve a strong acousto-optical/optomechanical coupling in air-slot phoxonic crystal structures by utilizing surface acoustic modes. - Highlights: • Two-dimensional air-slot phoxonic crystal cavities which can confine simultaneously optical and acoustic waves are proposed. • The acoustic and optical waves are highly confined near/in the air-slot. • The high overlap of the photonic and phononic cavity modes significantly enhances the moving interface effect. • Different factors which affect the acousto-optical coupling are discussed.

  2. Novel design of electrical sensing interface for prosthetic limbs using optical micro cavities

    Science.gov (United States)

    Ali, Amir R.; Kamel, Mohamed A.

    2018-04-01

    This paper uses optical whispering galley modes (WGM) cavities to construct a new electrical sensing interface between prosthetic limb and the brain. The sensing element will detect the action potential signal in the neural membrane and the prosthetic limb will be actuated accordingly. The element is a WGM dielectric polymeric cavity. WGM based optical cavities can achieve very high values of sensitivity and quality factor; thus, any minute perturbations in the morphology of the cavity can be captured and measured. The action potential signal will produce an applied external electric field on the dielectric cavity causing it to deform due to the electrostriction effect. The resulting deformation will cause WGM shifts in the transmission spectrum of the cavity. Thus, the action potential or the applied electric field can be measured using these shifts. In this paper the action potential signal will be simulated through the use of a function generator and two metal electrodes. The sensing element will be situated between these electrodes to detect the electrical signal passing through. The achieved sensitivity is 27.5 pm/V in measuring the simulated action potential signal; and 0.32 pm/V.m-1 in measuring the applied electric field due to the passage of the simulated signal.

  3. Parametric feedback cooling of a single atom inside on optical cavity

    International Nuclear Information System (INIS)

    Tatjana Wilk

    2014-01-01

    An optical cavity can be used as a kind of intensifier to study radiation features of an atom, which are hard to detect in free space, like squeezing. Such experiments make use of strong coupling between atom and cavity mode, which experimentally requires the atom to be well localized in the cavity mode. This can be achieved using feedback on the atomic motion: from intensity variations of a probe beam transmitted through the cavity information about the atomic motion is gained, which is used to synchronously modulate the trapping potential holding the atom, leading to cooling and better localization. Here, we report on efficient parametric feedback cooling of a single atom held in an intra-cavity standing wave dipole trap. In contrast to previous feedback strategies, this scheme cools the fast axial oscillation of the atom as well as the slower radial motion. (author)

  4. Temperature Sensitivity of an Atomic Vapor Cell-Based Dispersion-Enhanced Optical Cavity

    Science.gov (United States)

    Myneni, K.; Smith, D. D.; Chang, H.; Luckay, H. A.

    2015-01-01

    Enhancement of the response of an optical cavity to a change in optical path length, through the use of an intracavity fast-light medium, has previously been demonstrated experimentally and described theoretically for an atomic vapor cell as the intracavity resonant absorber. This phenomenon may be used to enhance both the scale factor and sensitivity of an optical cavity mode to the change in path length, e.g. in gyroscopic applications. We study the temperature sensitivity of the on-resonant scale factor enhancement, S(sub o), due to the thermal sensitivity of the lower-level atom density in an atomic vapor cell, specifically for the case of the Rb-87 D(sub 2) transition. A semi-empirical model of the temperature-dependence of the absorption profile, characterized by two parameters, a(sub o)(T) and gamma(sub a)(T) allows the temperature-dependence of the cavity response, S(sub o)(T) and dS(sub o)/dT to be predicted over a range of temperature. We compare the predictions to experiment. Our model will be useful in determining the useful range for S(sub o), given the practical constraints on temperature stability for an atomic vapor cell.

  5. Temporal characterization of FEL micropulses as function of cavity length detuning using frequency-resolved optical gating

    Energy Technology Data Exchange (ETDEWEB)

    Richman, B.A. [Stanford Univ., CA (United States); DeLong, K.W.; Trebino, R. [Sandia National Lab., Livermore, CA (United States)

    1995-12-31

    Results of frequency resolved optical gating (FROG) measurements on the Stanford mid-IR FEL system show the effect of FEL cavity length detuning on the micropulse temporal structure. The FROG technique enables the acquisition of complete and uniquely invertible amplitude and phase temporal dependence of optical pulses. Unambiguous phase and amplitude profiles are recovered from the data. The optical pulses are nearly transform limited, and the pulse length increases with cavity length detuning.

  6. Scheme for generating the singlet state of three atoms trapped in distant cavities coupled by optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dong-Yang [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Wen, Jing-Ji [College of Foundation Science, Harbin University of Commerce, Harbin, Heilongjiang 150028 (China); Bai, Cheng-Hua; Hu, Shi; Cui, Wen-Xue [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Wang, Hong-Fu, E-mail: hfwang@ybu.edu.cn [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Zhu, Ai-Dong [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Zhang, Shou, E-mail: szhang@ybu.edu.cn [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China)

    2015-09-15

    An effective scheme is proposed to generate the singlet state with three four-level atoms trapped in three distant cavities connected with each other by three optical fibers, respectively. After a series of appropriate atom–cavity interactions, which can be arbitrarily controlled via the selective pairing of Raman transitions and corresponding optical switches, a three-atom singlet state can be successfully generated. The influence of atomic spontaneous decay, photon leakage of cavities and optical fibers on the fidelity of the state is numerically simulated showing that the three-atom singlet state can be generated with high fidelity by choosing the experimental parameters appropriately.

  7. Complex ABCD transformations for optical ring cavities with losses and gain

    International Nuclear Information System (INIS)

    Kudashov, V N; Radin, A M; Plachenov, A B

    1999-01-01

    Complex ABCD field transformations are investigated for inhomogeneous optical ring cavities with losses and gain. It is shown that the sets of eigenfunctions, corresponding to counterpropagating waves, are really biorthogonal: the functions in each of these sets are really orthogonal relative to one another, and have a complex weighting factor independent of the mode number. Bidirectional and unidirectional stability conditions are formulated for such cavities. These conditions are qualitatively different from those for loss-free cavities. A simple algorithm is proposed for the evaluation of the ABCD matrix for a medium with an arbitrary longitudinal inhomogeneity along the beam. (laser applications and other topics in quantum electronics)

  8. On the Theory of Coupled Modes in Optical Cavity-Waveguide Structures

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; de Lasson, Jakob Rosenkrantz; Heuck, Mikkel

    2017-01-01

    Light propagation in systems of optical cavities coupled to waveguides can be conveniently described by a general rate equation model known as (temporal) coupled mode theory (CMT). We present an alternative derivation of the CMT for optical cavitywaveguide structures, which explicitly relies...... in the coupled systems. Practical application of the theory is illustrated using example calculations in one and two dimensions....

  9. Frequency-feedback cavity enhanced spectrometer

    Science.gov (United States)

    Hovde, David Christian; Gomez, Anthony

    2015-08-18

    A spectrometer comprising an optical cavity, a light source capable of producing light at one or more wavelengths transmitted by the cavity and with the light directed at the cavity, a detector and optics positioned to collect light transmitted by the cavity, feedback electronics causing oscillation of amplitude of the optical signal on the detector at a frequency that depends on cavity losses, and a sensor measuring the oscillation frequency to determine the cavity losses.

  10. Production cavity and central optics for a light shining through a wall experiment

    International Nuclear Information System (INIS)

    Hodajerdi, Reza

    2015-02-01

    The unexplained nature of dark matter and dark energy is a prominent reason for investigating physics beyond the standard model of particle physics (SM). Some extensions of the SM propose weakly interacting slim particles (WISPs). In an attempt to prove the existence of these particles, Light shining through the wall (LSW) experiments explore a very weak coupling between WISPs and photons (and viceversa). LSW experiments employ high-power lasers that provide a well defined flux of photons for the WISP-Photon conversion. The ALPS-I experiment at DESY in Hamburg was the first successful experiment with a high finesse optical resonator to enhance the laser power in a strong magnetic field in order to increase the photon to WISP conversion probability. The ALPS-II experimental concept adds a second optical cavity to also increase the reconversion probability. Both cavities are separated by a wall, amplify light at 1064 nm and share a common optical axis. Operating these two cavities inside 20 straightened HERA superconducting dipole magnets and using a transition edge sensor (TES) as a single photon detector will make the ALPS-II experiment almost three orders of magnitude more sensitive than its predecessor. Since photons, originating from reconverted WISPs in the regeneration cavity (RC) have 1064 nm wavelengths, the RC has to be locked to the production cavity (PC) with light of a different wavelength. Therefore frequency doubled PCs light will be used to lock the RC. This 532 nm light shall not arrive at the TES to prevent background noise. To achieve this, an optical attenuation system for wavelengths different from 1064 nm is required. In my thesis, the required attenuation was estimated and an optical setup was proposed and constructed and tested. It attenuates green photons by a factor of of 10 -18 and transmits 85% of the infrared photons. Furthermore the high finesse production cavity of ALPS-IIa was set up and characterized during this thesis. The PC reached

  11. Complex optical/UV and X-ray variability of the Seyfert 1 galaxy 1H 0419-577

    Science.gov (United States)

    Pal, Main; Dewangan, Gulab C.; Kembhavi, Ajit K.; Misra, Ranjeev; Naik, Sachindra

    2018-01-01

    We present detailed broad-band UV/optical to X-ray spectral variability of the Seyfert 1 galaxy 1H 0419-577 using six XMM-Newton observations performed during 2002-2003. These observations covered a large amplitude variability event in which the soft X-ray (0.3-2 keV) count rate increased by a factor of ∼4 in six months. The X-ray spectra during the variability are well described by a model consisting of a primary power law, blurred and distant reflection. The 2-10 keV power-law flux varied by a factor of ∼7 while the 0.3-2 keV soft X-ray excess flux derived from the blurred reflection component varied only by a factor of ∼2. The variability event was also observed in the optical and UV bands but the variability amplitudes were only at the 6-10 per cent level. The variations in the optical and UV bands appear to follow the variations in the X-ray band. During the rising phase, the optical bands appear to lag behind the UV band but during the declining phase, the optical bands appear to lead the UV band. Such behaviour is not expected in the reprocessing models where the optical/UV emission is the result of reprocessing of X-ray emission in the accretion disc. The delayed contribution of the broad emission lines in the UV band or the changes in the accretion disc/corona geometry combined with X-ray reprocessing may give rise to the observed behaviour of the variations.

  12. Matrix Optical Absorption in UV-MALDI MS.

    Science.gov (United States)

    Robinson, Kenneth N; Steven, Rory T; Bunch, Josephine

    2018-03-01

    In ultraviolet matrix-assisted laser desorption/ionization mass spectrometry (UV-MALDI MS) matrix compound optical absorption governs the uptake of laser energy, which in turn has a strong influence on experimental results. Despite this, quantitative absorption measurements are lacking for most matrix compounds. Furthermore, despite the use of UV-MALDI MS to detect a vast range of compounds, investigations into the effects of laser energy have been primarily restricted to single classes of analytes. We report the absolute solid state absorption spectra of the matrix compounds α-cyano-4-hydroxycinnamic acid (CHCA), para-nitroaniline (PNA), 2-mercaptobenzothiazole (MBT), 2,5-dihydroxybenzoic acid (2,5-DHB), and 2,4,6-trihydroxyacetophenone (THAP). The desorption/ionization characteristics of these matrix compounds with respect to laser fluence was investigated using mixed systems of matrix with either angiotensin II, PC(34:1) lipid standard, or haloperidol, acting as representatives for typical classes of analyte encountered in UV-MALDI MS. The first absolute solid phase spectra for PNA, MBT, and THAP are reported; additionally, inconsistencies between previously published spectra for CHCA are resolved. In light of these findings, suggestions are made for experimental optimization with regards to matrix and laser wavelength selection. The relationship between matrix optical cross-section and wavelength-dependant threshold fluence, fluence of maximum ion yield, and R, a new descriptor for the change in ion intensity with fluence, are described. A matrix cross-section of 1.3 × 10 -17 cm -2 was identified as a potential minimum for desorption/ionization of analytes. Graphical Abstract ᅟ.

  13. Cavity Formation Modeling of Fiber Fuse in Single-Mode Optical Fibers

    Directory of Open Access Journals (Sweden)

    Yoshito Shuto

    2017-01-01

    Full Text Available The evolution of a fiber-fuse phenomenon in a single-mode optical fiber was studied theoretically. To clarify both the silica-glass densification and cavity formation, which have been observed in fiber fuse propagation, we investigated a nonlinear oscillation model using the Van Der Pol equation. This model was able to phenomenologically explain both the densification of the core material and the formation of periodic cavities in the core layer as a result of a relaxation oscillation.

  14. Nonlinear estimation of ring-down time for a Fabry-Perot optical cavity.

    Science.gov (United States)

    Kallapur, Abhijit G; Boyson, Toby K; Petersen, Ian R; Harb, Charles C

    2011-03-28

    This paper discusses the application of a discrete-time extended Kalman filter (EKF) to the problem of estimating the decay time constant for a Fabry-Perot optical cavity for cavity ring-down spectroscopy (CRDS). The data for the estimation process is obtained from a CRDS experimental setup in terms of the light intensity at the output of the cavity. The cavity is held in lock with the input laser frequency by controlling the distance between the mirrors within the cavity by means of a proportional-integral (PI) controller. The cavity is purged with nitrogen and placed under vacuum before chopping the incident light at 25 KHz and recording the light intensity at its output. In spite of beginning the EKF estimation process with uncertainties in the initial value for the decay time constant, its estimates converge well within a small neighborhood of the expected value for the decay time constant of the cavity within a few ring-down cycles. Also, the EKF estimation results for the decay time constant are compared to those obtained using the Levenberg-Marquardt estimation scheme.

  15. 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

  16. Flight-Like Optical Reference Cavity for GRACE Follow-On Laser Frequency Stabilization

    Science.gov (United States)

    Folkner, W. M.; deVine, G.; Klipstein, W. M.; McKenzie, K.; Spero, R.; Thompson, R.; Yu, N.; Stephens, M.; Leitch, J.; Pierce, R.; hide

    2011-01-01

    We describe a prototype optical cavity and associated optics that has been developed to provide a stable frequency reference for a future space-based laser ranging system. This instrument is being considered for inclusion as a technology demonstration on the recently announced GRACE follow-on mission, which will monitor variations in the Earth's gravity field.

  17. Simulation of noise-assisted transport via optical cavity networks

    International Nuclear Information System (INIS)

    Caruso, Filippo; Plenio, Martin B.; Spagnolo, Nicolo; Vitelli, Chiara; Sciarrino, Fabio

    2011-01-01

    Recently, the presence of noise has been found to play a key role in assisting the transport of energy and information in complex quantum networks and even in biomolecular systems. Here we propose an experimentally realizable optical network scheme for the demonstration of the basic mechanisms underlying noise-assisted transport. The proposed system consists of a network of coupled quantum-optical cavities, injected with a single photon, whose transmission efficiency can be measured. Introducing dephasing in the photon path, this system exhibits a characteristic enhancement of the transport efficiency that can be observed with presently available technology.

  18. UV/Vis visible optical waveguides fabricated using organic-inorganic nanocomposite layers.

    Science.gov (United States)

    Simone, Giuseppina; Perozziello, Gerardo

    2011-03-01

    Nanocomposite layers based on silica nanoparticles and a methacrylate matrix are synthesized by a solvent-free process and characterized in order to realize UV/Vis transparent optical waveguides. Chemical functionalization of the silica nanoparticles permits to interface the polymers and the silica. The refractive index, roughness and wettability and the machinability of the layers can be tuned changing the silica nanoparticle concentration and chemical modification of the surface of the nanoparticles. The optical transparency of the layers is affected by the nanoparticles organization between the organic chains, while it increased proportionally with respect to silica concentration. Nanocomposite layers with a concentration of 40 wt% in silica reached UV transparency for a wavelength of 250 nm. UV/Vis transparent waveguides were micromilled through nanocomposite layers and characterized. Propagation losses were measured to be around 1 dB cm(-1) at a wavelength of 350 nm.

  19. Method of increasing power within an optical cavity with long path lengths

    Energy Technology Data Exchange (ETDEWEB)

    Leen, John Brian; Bramall, Nathan E.

    2018-03-13

    A cavity-enhanced absorption spectroscopy instrument has an optical cavity with two or more cavity mirrors, one mirror of which having a hole or other aperture for injecting a light beam, and the same or another mirror of which being partially transmissive to allow exit of light to a detector. A spherical-spherical configuration with at least one astigmatic mirror or a spherical-cylindrical configuration where the spherical mirror could also be astigmatic prevents a reentrant condition wherein the injected beam would prematurely exit the cavity through the aperture. This combination substantially increases the number of passes of the injected beam through a sample volume for sensitive detection of chemical species even in less than ideal conditions including low power laser or LED sources, poor mirror reflectivity or detector noise at the wavelengths of interest, or cavity alignment issues such as vibration or temperature and pressure changes.

  20. Soil-embedded optical fiber sensing cable interrogated by Brillouin optical time-domain reflectometry (B-OTDR) and optical frequency-domain reflectometry (OFDR) for embedded cavity detection and sinkhole warning system

    International Nuclear Information System (INIS)

    Lanticq, V; Bourgeois, E; Delepine-Lesoille, S; Magnien, P; Dieleman, L; Vinceslas, G; Sang, A

    2009-01-01

    A soil-embedded optical fiber sensing cable is evaluated for an embedded cavity detection and sinkhole warning system in railway tunnels. Tests were performed on a decametric structure equipped with an embedded 110 m long fiber optic cable. Both Brillouin optical time-domain reflectometry (B-OTDR) and optical frequency-domain reflectometry (OFDR) sensing techniques were used for cable interrogation, yielding results that were in good qualitative agreement with finite-element calculations. Theoretical and experimental comparison enabled physical interpretation of the influence of ground properties, and the analysis of embedded cavity size and position. A 5 mm embedded cavity located 2 m away from the sensing cable was detected. The commercially available sensing cable remained intact after soil collapse. Specificities of each technique are analyzed in view of the application requirements. For tunnel monitoring, the OFDR technique was determined to be more viable than the B-OTDR due to higher spatial resolution, resulting in better detection and size determination of the embedded cavities. Conclusions of this investigation gave outlines for future field use of distributed strain-sensing methods under railways and more precisely enabled designing a warning system suited to the Ebersviller tunnel specificities

  1. A QUASAR CATALOG WITH SIMULTANEOUS UV, OPTICAL, AND X-RAY OBSERVATIONS BY SWIFT

    International Nuclear Information System (INIS)

    Wu Jian; Grupe, Dirk; Koch, Scott; Gelbord, Jonathan; Schneider, Donald P.; Gronwall, Caryl; Porterfield, Blair L.; Vanden Berk, Daniel; Wesolowski, Sarah

    2012-01-01

    We have compiled a catalog of optically selected quasars with simultaneous observations in UV/optical and X-ray bands by the Swift Gamma-ray Burst Explorer. Objects in this catalog are identified by matching the Swift pointings with the Sloan Digital Sky Survey Data Release 5 quasar catalog. The final catalog contains 843 objects, among which 637 have both Ultraviolet Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations and 354 of which are detected by both instruments. The overall X-ray detection rate is ∼60% which rises to ∼85% among sources with at least 10 ks of XRT exposure time. We construct the time-averaged spectral energy distribution (SED) for each of the 354 quasars using UVOT photometric measurements and XRT spectra. From model fits to these SEDs, we find that the big blue bump contributes about ∼0.3 dex to the quasar luminosity. We re-visit the α ox -L 2500Å relation by selecting a clean sample with only Type 1 radio-quiet quasars; the dispersion of this relation is reduced by at least 15% compared with studies that use non-simultaneous UV/optical and X-ray data. We only found a weak correlation between L bol /L Edd and α UV . We do not find significant correlations between α x and α ox , α ox and α UV , and α x and log L(0.3-10 keV). The correlations between α UV and α x , α ox and α x , α ox and α UV , L bol /L Edd and α x , and L bol /L Edd and α ox are stronger among low-redshift quasars, indicating that these correlations are likely driven by the changes of SED shape with accretion state.

  2. Single-mode, All-Solid-State Nd:YAG Laser Pumped UV Converter

    Science.gov (United States)

    Prasad, Narasimha S.; Armstrong, Darrell, J.; Edwards, William C.; Singh, Upendra N.

    2008-01-01

    In this paper, the status of a high-energy, all solid-state Nd:YAG laser pumped nonlinear optics based UV converter development is discussed. The high-energy UV transmitter technology is being developed for ozone sensing applications from space based platforms using differential lidar technique. The goal is to generate greater than 200 mJ/pulse with 10-50 Hz PRF at wavelengths of 308 nm and 320 nm. A diode-pumped, all-solid-state and single longitudinal mode Nd:YAG laser designed to provide conductively cooled operation at 1064 nm has been built and tested. Currently, this pump laser provides an output pulse energy of >1 J/pulse at 50 Hz PRF and a pulsewidth of 22 ns with an electrical-to-optical system efficiency of greater than 7% and a M(sup 2) value of UV converter arrangement basically consists of an IR Optical Parametric Oscillator (OPO) and a Sum Frequency Generator (SFG) setups that are pumped by 532 nm wavelength obtained via Second Harmonic Generation (SHG). In this paper, the operation of an inter cavity SFG with CW laser seeding scheme generating 320 nm wavelength is presented. Efforts are underway to improve conversion efficiency of this mJ class UV converter by modifying the spatial beam profile of the pump laser.

  3. High power deep UV-LEDs for analytical optical instrumentation

    Czech Academy of Sciences Publication Activity Database

    Li, Y.; Dvořák, Miloš; Nesterenko, P. N.; Nuchtavorn, N.; Macka, M.

    2018-01-01

    Roč. 255, č. 2 (2018), s. 1238-1243 ISSN 0925-4005 Institutional support: RVO:68081715 Keywords : deep UV Light emitting diodes (LEDs) * optical detection * portable analytical instrumentation Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 5.401, year: 2016

  4. Novel Cavities in Vertical External Cavity Surface Emitting Lasers for Emission in Broad Spectral Region by Means of Nonlinear Frequency Conversion

    Science.gov (United States)

    Lukowski, Michal L.

    Optically pumped semiconductor vertical external cavity surface emitting lasers (VECSEL) were first demonstrated in the mid 1990's. Due to the unique design properties of extended cavity lasers VECSELs have been able to provide tunable, high-output powers while maintaining excellent beam quality. These features offer a wide range of possible applications in areas such as medicine, spectroscopy, defense, imaging, communications and entertainment. Nowadays, newly developed VECSELs, cover the spectral regions from red (600 nm) to around 5 microm. By taking the advantage of the open cavity design, the emission can be further expanded to UV or THz regions by the means of intracavity nonlinear frequency generation. The objective of this dissertation is to investigate and extend the capabilities of high-power VECSELs by utilizing novel nonlinear conversion techniques. Optically pumped VECSELs based on GaAs semiconductor heterostructures have been demonstrated to provide exceptionally high output powers covering the 900 to 1200 nm spectral region with diffraction limited beam quality. The free space cavity design allows for access to the high intracavity circulating powers where high efficiency nonlinear frequency conversions and wavelength tuning can be obtained. As an introduction, this dissertation consists of a brief history of the development of VECSELs as well as wafer design, chip fabrication and resonator cavity design for optimal frequency conversion. Specifically, the different types of laser cavities such as: linear cavity, V-shaped cavity and patented T-shaped cavity are described, since their optimization is crucial for transverse mode quality, stability, tunability and efficient frequency conversion. All types of nonlinear conversions such as second harmonic, sum frequency and difference frequency generation are discussed in extensive detail. The theoretical simulation and the development of the high-power, tunable blue and green VECSEL by the means of type I

  5. 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.

  6. Cavity-Enhanced Raman Spectroscopy of Natural Gas with Optical Feedback cw-Diode Lasers.

    Science.gov (United States)

    Hippler, Michael

    2015-08-04

    We report on improvements made on our previously introduced technique of cavity-enhanced Raman spectroscopy (CERS) with optical feedback cw-diode lasers in the gas phase, including a new mode-matching procedure which keeps the laser in resonance with the optical cavity without inducing long-term frequency shifts of the laser, and using a new CCD camera with improved noise performance. With 10 mW of 636.2 nm diode laser excitation and 30 s integration time, cavity enhancement achieves noise-equivalent detection limits below 1 mbar at 1 bar total pressure, depending on Raman cross sections. Detection limits can be easily improved using higher power diodes. We further demonstrate a relevant analytical application of CERS, the multicomponent analysis of natural gas samples. Several spectroscopic features have been identified and characterized. CERS with low power diode lasers is suitable for online monitoring of natural gas mixtures with sensitivity and spectroscopic selectivity, including monitoring H2, H2S, N2, CO2, and alkanes.

  7. Auxiliary-cavity-assisted ground-state cooling of an optically levitated nanosphere in the unresolved-sideband regime

    Science.gov (United States)

    Feng, Jin-Shan; Tan, Lei; Gu, Huai-Qiang; Liu, Wu-Ming

    2017-12-01

    We theoretically analyze the ground-state cooling of an optically levitated nanosphere in the unresolved-sideband regime by introducing a coupled high-quality-factor cavity. On account of the quantum interference stemming from the presence of the coupled cavity, the spectral density of the optical force exerting on the nanosphere gets changed and then the symmetry between the heating and the cooling processes is broken. Through adjusting the detuning of a strong-dissipative cavity mode, one obtains an enhanced net cooling rate for the nanosphere. It is illustrated that the ground-state cooling can be realized in the unresolved sideband regime even if the effective optomechanical coupling is weaker than the frequency of the nanosphere, which can be understood by the picture that the effective interplay of the nanosphere and the auxiliary cavity mode brings the system back to an effective resolved regime. Besides, the coupled cavity refines the dynamical stability of the system.

  8. Cavity Enhanced Absorption Spectroscopy in Air Pollution Monitoring

    Directory of Open Access Journals (Sweden)

    Janusz MIKOŁAJCZYK

    2015-10-01

    Full Text Available The paper presents some practical aspects of cavity enhanced absorption spectroscopy application in detection of nitrogen dioxide (NO2, nitrous oxide (N2O, nitric oxide (NO and carbon monoxide (CO. These gases are very important for monitoring of environment. There are shown results of lab-setups for N2O, NO, CO detection and portable sensor of NO2. The portable instrument operates in the UV spectral range and reaches a level of single ppb. The lab–devices use high precision mid-infrared spectroscopy and they was demonstrated during testing the laboratory air. These sensors are able to measure concentration at the ppb level using quantum cascade lasers, high quality optical cavities and modern MCT detection modules. It makes it possible to apply such sensors in monitoring the atmosphere quality.

  9. Cavity Ring-Down Absorption of O2 in Air as a Temperature Sensor for an Open and a Cryogenic Optical Cavity.

    Science.gov (United States)

    Nyaupane, Parashu R; Perez-Delgado, Yasnahir; Camejo, David; Wright, Lesley M; Manzanares, Carlos E

    2017-05-01

    The A-band of oxygen has been measured at low resolution at temperatures between 90 K and 373 K using the phase shift cavity ring down (PS-CRD) technique. For temperatures between 90 K and 295 K, the PS-CRD technique presented here involves an optical cavity attached to a cryostat. The static cell and mirrors of the optical cavity are all inside a vacuum chamber at the same temperature of the cryostat. The temperature of the cell can be changed between 77 K and 295 K. For temperatures above 295 K, a hollow glass cylindrical tube without windows has been inserted inside an optical cavity to measure the temperature of air flowing through the tube. The cavity consists of two highly reflective mirrors which are mounted parallel to each other and separated by a distance of 93 cm. In this experiment, air is passed through a heated tube. The temperature of the air flowing through the tube is determined by measuring the intensity of the oxygen absorption as a function of the wavenumber. The A-band of oxygen is measured between 298 K and 373 K, with several air flow rates. To obtain the temperature, the energy of the lower rotational state for seven selected rotational transitions is linearly fitted to a logarithmic function that contains the relative intensity of the rotational transition, the initial and final rotational quantum numbers, and the energy of the transition. Accuracy of the temperature measurement is determined by comparing the calculated temperature from the spectra with the temperature obtained from a calibrated thermocouple inserted at the center of the tube. This flowing air temperature sensor will be used to measure the temperatures of cooling air at the input (cold air) and output (hot air) after cooling the blades of a laboratory gas turbine. The results could contribute to improvements in turbine blade cooling design.

  10. Why soft UV-A damages DNA: An optical micromanipulation study

    Science.gov (United States)

    Rapp, A.; Greulich, K. O.

    2013-09-01

    Optical micromanipulation studies have solved a puzzle on DNA damage and repair. Such knowledge is crucial for understanding cancer and ageing. So far it was not understood, why the soft UV component of sunlight, UV-A, causes the dangerous DNA double strand breaks. The energy of UV-A photons is below 4 eV per photon, too low to directly cleave the corresponding chemical bonds in DNA. This is occasionally used to claim that artificial sunbeds, which mainly use UV-A, would not impose a risk on health. UV-A is only sufficient for induction of single strand breaks. The essential new observation is that, when on the opposite strand there is another single strand break at a distance of up to 20 base pairs. These two breaks will be converted into a break of the whole double strand with all its known consequences for cancer and ageing. However, in natural sun the effect is counteracted. Simultaneous red light illumination reduces UV induced DNA damages to 1/3. Since sunlight has a red component, skin tanning with natural sun is not as risky as might appear at a first glance.

  11. A QUASAR CATALOG WITH SIMULTANEOUS UV, OPTICAL, AND X-RAY OBSERVATIONS BY SWIFT

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jian; Grupe, Dirk; Koch, Scott; Gelbord, Jonathan; Schneider, Donald P.; Gronwall, Caryl; Porterfield, Blair L. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Vanden Berk, Daniel; Wesolowski, Sarah, E-mail: jwu@astro.psu.edu [Department of Physics, Saint Vincent College, 300 Fraser Purchase Road, Latrobe, PA 15650 (United States)

    2012-08-01

    We have compiled a catalog of optically selected quasars with simultaneous observations in UV/optical and X-ray bands by the Swift Gamma-ray Burst Explorer. Objects in this catalog are identified by matching the Swift pointings with the Sloan Digital Sky Survey Data Release 5 quasar catalog. The final catalog contains 843 objects, among which 637 have both Ultraviolet Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations and 354 of which are detected by both instruments. The overall X-ray detection rate is {approx}60% which rises to {approx}85% among sources with at least 10 ks of XRT exposure time. We construct the time-averaged spectral energy distribution (SED) for each of the 354 quasars using UVOT photometric measurements and XRT spectra. From model fits to these SEDs, we find that the big blue bump contributes about {approx}0.3 dex to the quasar luminosity. We re-visit the {alpha}{sub ox}-L{sub 2500A} relation by selecting a clean sample with only Type 1 radio-quiet quasars; the dispersion of this relation is reduced by at least 15% compared with studies that use non-simultaneous UV/optical and X-ray data. We only found a weak correlation between L{sub bol}/L{sub Edd} and {alpha}{sub UV}. We do not find significant correlations between {alpha}{sub x} and {alpha}{sub ox}, {alpha}{sub ox} and {alpha}{sub UV}, and {alpha}{sub x} and log L(0.3-10 keV). The correlations between {alpha}{sub UV} and {alpha}{sub x}, {alpha}{sub ox} and {alpha}{sub x}, {alpha}{sub ox} and {alpha}{sub UV}, L{sub bol}/L{sub Edd} and {alpha}{sub x}, and L{sub bol}/L{sub Edd} and {alpha}{sub ox} are stronger among low-redshift quasars, indicating that these correlations are likely driven by the changes of SED shape with accretion state.

  12. Optical feedback in dfb quantum cascade laser for mid-infrared cavity ring-down spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Terabayashi, Ryohei, E-mail: terabayashi.ryouhei@h.mbox.nagoya-u.ac.jp; Sonnenschein, Volker, E-mail: volker@nagoya-u.jp; Tomita, Hideki, E-mail: tomita@nagoya-u.jp; Hayashi, Noriyoshi, E-mail: hayashi.noriyoshi@h.mbox.nagoya-u.ac.jp; Kato, Shusuke, E-mail: katou.shuusuke@f.mbox.nagoya-u.ac.jp; Jin, Lei, E-mail: kin@nuee.nagoya-u.ac.jp; Yamanaka, Masahito, E-mail: yamanaka@nuee.nagoya-u.ac.jp; Nishizawa, Norihiko, E-mail: nishizawa@nuee.nagoya-u.ac.jp [Nagoya University, Department of Quantum Engineering, Graduate School of Engineering (Japan); Sato, Atsushi, E-mail: atsushi.sato@sekisui.com; Nozawa, Kohei, E-mail: kohei.nozawa@sekisui.com; Hashizume, Kenta, E-mail: kenta.hashizume@sekisui.com; Oh-hara, Toshinari, E-mail: toshinari.ohara@sekisui.com [Sekisui Medical Co., Ltd., Drug Development Solutions Center (Japan); Iguchi, Tetsuo, E-mail: t-iguchi@nucl.nagoya-u.ac.jp [Nagoya University, Department of Quantum Engineering, Graduate School of Engineering (Japan)

    2017-11-15

    A simple external optical feedback system has been applied to a distributed feedback quantum cascade laser (DFB QCL) for cavity ring-down spectroscopy (CRDS) and a clear effect of feedback was observed. A long external feedback path length of up to 4m can decrease the QCL linewidth to around 50kHz, which is of the order of the transmission linewidth of our high finesse ring-down cavity. The power spectral density of the transmission signal from high finesse cavity reveals that the noise at frequencies above 20kHz is reduced dramatically.

  13. Asbestos as 'toxic short-circuit' optic-fibre for UV within the cell-net: — Likely roles and hazards for secret UV and IR metabolism

    International Nuclear Information System (INIS)

    Traill, Robert R

    2011-01-01

    The most toxic asbestos fibres have widths 250nm-10nm, and this toxicity is 'physical', which could mean either mechanical or optical: Tangling with chromosomes is a mechanical hazard occasionally reported, and fibres 100nm wide — or chrysotile (white asbestos) is >150nm. In both cases, UV A /UV B -transmission would then predominate. (Chrysotile 150nm might be benign — escaping both mechanical and optical!). But what would generate such UV, and why would its transmission be toxic? Thar and Kühl (J.Theor.Biol.:2004) explain that the long mitochondria on microtubules may be able to act as UV-lasers, (and many observers since Gurwitsch 1923 have reported ultraweak UV emissions escaping from all types of living bio-tissue). That all suggests some universal secret role for UV, apparently related to mitosis. Insertion of fibre 'short-circuits' could then cause upsets in mitosis-control, and hence DNA irregularities. Such UV-control could parallel similar lower-powered Infra-Red control-systems (as considered elsewhere for coaxial myelin; or as portrayed by G.Albrecht-Buehler's online animations etc.); and the traditional short mitochondria seem better suited for this IR task.

  14. Electrically Injected UV-Visible Nanowire Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, George T.; Li, Changyi; Li, Qiming; Liu, Sheng; Wright, Jeremy Benjamin; Brener, Igal; Luk, Ting -Shan; Chow, Weng W.; Leung, Benjamin; Figiel, Jeffrey J.; Koleske, Daniel D.; Lu, Tzu-Ming

    2015-09-01

    There is strong interest in minimizing the volume of lasers to enable ultracompact, low-power, coherent light sources. Nanowires represent an ideal candidate for such nanolasers as stand-alone optical cavities and gain media, and optically pumped nanowire lasing has been demonstrated in several semiconductor systems. Electrically injected nanowire lasers are needed to realize actual working devices but have been elusive due to limitations of current methods to address the requirement for nanowire device heterostructures with high material quality, controlled doping and geometry, low optical loss, and efficient carrier injection. In this project we proposed to demonstrate electrically injected single nanowire lasers emitting in the important UV to visible wavelengths. Our approach to simultaneously address these challenges is based on high quality III-nitride nanowire device heterostructures with precisely controlled geometries and strong gain and mode confinement to minimize lasing thresholds, enabled by a unique top-down nanowire fabrication technique.

  15. Direct UV-Written Integrated Optical Beam Combiner for Stellar Interferometry

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael; Jocou, L.

    2007-01-01

    In this paper, we report the fabrication of an optical-beam combiner for stellar interferometry by means of direct ultraviolet (UV) writing. The component is shown to have good performance (fringe contrast > 95%, total loss similar to 0.7, -40-dB crosstalk, broadband operation covering at least...... the range 1.49-1.65 mu m, and low differential chromatic dispersion). The overall performance exceeds that of similar components currently used for astronomical research. This result, combined with the fast-prototyping ability of UV writing, opens up new possibilities for the realization of highly optimized...

  16. Normal mode splitting and ground state cooling in a Fabry—Perot optical cavity and transmission line resonator

    International Nuclear Information System (INIS)

    Chen Hua-Jun; Mi Xian-Wu

    2011-01-01

    Optomechanical dynamics in two systems which are a transmission line resonator and Fabrya—Perot optical cavity via radiation—pressure are investigated by linearized quantum Langevin equation. We work in the resolved sideband regime where the oscillator resonance frequency exceeds the cavity linewidth. Normal mode splittings of the mechanical resonator as a pure result of the coupling interaction in the two optomechanical systems is studied, and we make a comparison of normal mode splitting of mechanical resonator between the two systems. In the optical cavity, the normal mode splitting of the movable mirror approaches the latest experiment very well. In addition, an approximation scheme is introduced to demonstrate the ground state cooling, and we make a comparison of cooling between the two systems dominated by two key factors, which are the initial bath temperature and the mechanical quality factor. Since both the normal mode splitting and cooling require working in the resolved sideband regime, whether the normal mode splitting influences the cooling of the mirror is considered. Considering the size of the mechanical resonator and precooling the system, the mechanical resonator in the transmission line resonator system is easier to achieve the ground state cooling than in optical cavity. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  17. An all-optical fiber optic photoacoustic transducer

    Science.gov (United States)

    Thathachary, Supriya V.; Motameni, Cameron; Ashkenazi, Shai

    2018-02-01

    A highly sensitive fiber-optic Fabry-Perot photoacoustic transducer is proposed in this work. The transducer will consist of separate transmit and receive fibers. The receiver will be composed of a Fabry-Perot Ultrasound sensor with a selfwritten waveguide with all-optical ultrasound detection with high sensitivity. In previous work, we have shown an increase in resonator Q-factor from 1900 to 3200 for a simulated Fabry-Perot ultrasound detector of 45 μm thickness upon including a waveguide to limit lateral power losses. Subsequently, we demonstrated a prototype device with 30nm gold mirrors and a cavity composed of the photosensitive polymer Benzocyclobutene. This 80 µm thick device showed an improvement in its Q-factor from 2500 to 5200 after a selfaligned waveguide was written into the cavity using UV exposure. Current work uses a significantly faster fabrication technique using a combination of UV-cured epoxies for the cavity medium, and the waveguide within it. This reduces the fabrication time from several hours to a few minutes, and significantly lowers the cost of fabrication. We use a dip-coating technique to deposit the polymer layer. Future work will include the use of Dielectric Bragg mirrors in place of gold to achieve better reflectivity, thereby further improving the Q-factor of the device. The complete transducer presents an ideal solution for intravascular imaging in cases where tissue differentiation is desirable, an important feature in interventional procedures where arterial perforation is a risk. The final design proposed comprises the transducer within a guidewire to guide interventions for Chronic Total Occlusions, a disease state for which there are currently no invasive imaging options.

  18. X-ray quantum optics with Moessbauer nuclei in thin-film cavities

    Energy Technology Data Exchange (ETDEWEB)

    Heeg, Kilian Peter

    2014-12-09

    In this thesis thin-film cavities with embedded Moessbauer nuclei probed by near-resonant X-ray light are studied from a quantum optical perspective. A theoretical framework is developed and compact expressions for the observables are derived for the linear excitation regime, which is encountered in current experiments. Even advanced cavity layouts can be modeled in excellent agreement with the results of previous experiments and semi-classical approaches. In the absence of magnetic hyperfine splitting, the spectral response of the system is found to be formed by tunable Fano profiles. An experimental implementation of this line shape control allows to extract spectroscopic signatures with high precision and to reconstruct the phase of the nuclear transition in good agreement with the theoretical predictions. The alignment of medium magnetization and polarization control of the X-rays enable to engineer advanced quantum optical level schemes, in which vacuum induced coherence effects are predicted and successfully demonstrated in an experiment. Furthermore, it is shown that group velocity control for x-ray pulses can be achieved in the cavity. A scheme for its observation is proposed and then employed to experimentally confirm sub-luminal X-ray propagation. Finally, non-linear effects, which could become accessible with future light sources, are explored and a non-linear line shape control mechanism is discussed.

  19. Ultrafast Optics: Vector Cavity Laser - Physics and Technology

    Science.gov (United States)

    2016-06-14

    with a quasi- vector cavity both numerically and experimentally. It is expected that through the study a deep and comprehensive understanding on the...799-801, Jun. 1997. 31. L. M. Zhao, D. Y. Tang, J. Wu, X. Q. Fu, and S. C. Wen , "Noise-like pulse in a gain-guided soliton fiber laser," Opt...solitons in a ring fiber laser," Optics Communications 281 (22), 5614 (2008). 110. L. M. Zhao, D. Y. Tang, J. Wu, X. Q. Fu, and S. C. Wen , "Noise-like

  20. Ultrafast Optics - Vector Cavity Lasers: Physics and Technology

    Science.gov (United States)

    2016-06-14

    with a quasi- vector cavity both numerically and experimentally. It is expected that through the study a deep and comprehensive understanding on the...799-801, Jun. 1997. 31. L. M. Zhao, D. Y. Tang, J. Wu, X. Q. Fu, and S. C. Wen , "Noise-like pulse in a gain-guided soliton fiber laser," Opt...solitons in a ring fiber laser," Optics Communications 281 (22), 5614 (2008). 110. L. M. Zhao, D. Y. Tang, J. Wu, X. Q. Fu, and S. C. Wen , "Noise-like

  1. Applying UV cameras for SO2 detection to distant or optically thick volcanic plumes

    Science.gov (United States)

    Kern, Christoph; Werner, Cynthia; Elias, Tamar; Sutton, A. Jeff; Lübcke, Peter

    2013-01-01

    Ultraviolet (UV) camera systems represent an exciting new technology for measuring two dimensional sulfur dioxide (SO2) distributions in volcanic plumes. The high frame rate of the cameras allows the retrieval of SO2 emission rates at time scales of 1 Hz or higher, thus allowing the investigation of high-frequency signals and making integrated and comparative studies with other high-data-rate volcano monitoring techniques possible. One drawback of the technique, however, is the limited spectral information recorded by the imaging systems. Here, a framework for simulating the sensitivity of UV cameras to various SO2 distributions is introduced. Both the wavelength-dependent transmittance of the optical imaging system and the radiative transfer in the atmosphere are modeled. The framework is then applied to study the behavior of different optical setups and used to simulate the response of these instruments to volcanic plumes containing varying SO2 and aerosol abundances located at various distances from the sensor. Results show that UV radiative transfer in and around distant and/or optically thick plumes typically leads to a lower sensitivity to SO2 than expected when assuming a standard Beer–Lambert absorption model. Furthermore, camera response is often non-linear in SO2 and dependent on distance to the plume and plume aerosol optical thickness and single scatter albedo. The model results are compared with camera measurements made at Kilauea Volcano (Hawaii) and a method for integrating moderate resolution differential optical absorption spectroscopy data with UV imagery to retrieve improved SO2 column densities is discussed.

  2. Integrated optical devices for wavelength division multiplexing using PECVD and direct UV writing techniques

    DEFF Research Database (Denmark)

    Zauner, Dan; Leistiko, Otto

    1999-01-01

    channel waveguides are presented: a conventional method and direct UV writing. It is shown that an optimized three layer glass structure yields directly UV written waveguides with low insertion losses. Integrated optical structures have been designed and fabricated. The impact of process variations...

  3. Poling of UV-written Waveguides

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Kristensen, Martin; Hübner, Jörg

    1999-01-01

    We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months......We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months...

  4. Overlapping double potential wells in a single optical microtube cavity with vernier-scale-like tuning effect

    International Nuclear Information System (INIS)

    Madani, A.; Schmidt, O. G.; Bolaños Quiñones, V. A.; Ma, L. B.; Jorgensen, M. R.; Miao, S. D.

    2016-01-01

    Spatially and temporally overlapping double potential wells are realized in a hybrid optical microtube cavity due to the coexistence of an aggregate of luminescent quantum dots embedded in the tube wall and the cone-shaped tube's geometry. The double potential wells produce two independent sets of optical modes with different sets of mode numbers, indicating phase velocity separation for the modes overlapping at the same frequency. The overlapping mode position can be tuned by modifying the tube cavity, where these mode sets shift with different magnitudes, allowing for a vernier-scale-like tuning effect.

  5. Cavity-enhanced spectroscopies

    CERN Document Server

    van Zee, Roger

    2003-01-01

    ""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

  6. All-periodically poled, high-power, continuous-wave, single-frequency tunable UV source.

    Science.gov (United States)

    Aadhi, A; Chaitanya N, Apurv; Jabir, M V; Singh, R P; Samanta, G K

    2015-01-01

    We report on experimental demonstration of an all-periodically poled, continuous-wave (CW), high-power, single-frequency, ultra-violet (UV) source. Based on internal second-harmonic-generation (SHG) of a CW singly resonant optical parametric oscillator (OPO) pumped in the green, the UV source provides tunable radiation across 398.94-417.08 nm. The compact source comprising of a 25-mm-long MgO-doped periodically poled stoichiometric lithium tantalate (MgO:sPPLT) crystal of period Λ(SLT)=8.5  μm for OPO and a 5-mm-long, multi-grating (Λ(KTP)=3.3, 3.4, 3.6 and 3.8 μm), periodically poled potassium titanium phosphate (PPKTP) for intra-cavity SHG, provides as much as 336 mW of UV power at 398.94 nm, corresponding to a green-to-UV conversion efficiency of ∼6.7%. In addition, the singly resonant OPO (SRO) provides 840 mW of idler at 1541.61 nm and substantial signal power of 108 mW at 812.33 nm transmitted through the high reflective cavity mirrors. UV source provides single-frequency radiation with instantaneous line-width of ∼18.3  MHz and power >100  mW in Gaussian beam profile (ellipticity >92%) across the entire tuning range. Access to lower UV wavelengths requires smaller grating periods to compensate high phase-mismatch resulting from high material dispersion in the UV wavelength range. Additionally, we have measured the normalized temperature and spectral acceptance bandwidth of PPKTP crystal in the UV wavelength range to be ∼2.25°C·cm and ∼0.15  nm·cm, respectively.

  7. Thermo-optical Characterization of Photothermal Optical Phase Shift Detection in Extended-Nano Channels and UV Detection of Biomolecules.

    Science.gov (United States)

    Shimizu, Hisashi; Miyawaki, Naoya; Asano, Yoshihiro; Mawatari, Kazuma; Kitamori, Takehiko

    2017-06-06

    The expansion of microfluidics research to nanofluidics requires absolutely sensitive and universal detection methods. Photothermal detection, which utilizes optical absorption and nonradiative relaxation, is promising for the sensitive detection of nonlabeled biomolecules in nanofluidic channels. We have previously developed a photothermal optical phase shift (POPS) detection method to detect nonfluorescent molecules sensitively, while a rapid decrease of the sensitivity in nanochannels and the introduction of an ultraviolet (UV) excitation system were issues to be addressed. In the present study, our primary aim is to characterize the POPS signal in terms of the thermo-optical properties and quantitatively evaluate the causes for the decrease in sensitivity. The UV excitation system is then introduced into the POPS detector to realize the sensitive detection of nonlabeled biomolecules. The UV-POPS detection system is designed and constructed from scratch based on a symmetric microscope. The results of simulations and experiments reveal that the sensitivity decreases due to a reduction of the detection volume, dissipation of the heat, and cancellation of the changes in the refractive indices. Finally, determination of the concentration of a nonlabeled protein (bovine serum albumin) is performed in a very thin 900 nm deep nanochannel. As a result, the limit of detection (LOD) is 2.3 μM (600 molecules in the 440 attoliter detection volume), which is as low as that previously obtained for our visible POPS detector. UV-POPS detection is thus expected be a powerful technique for the study of biomolecules, including DNAs and proteins confined in nanofluidic channels.

  8. Coherent stacking of picosecond laser pulses in a high-Q optical cavity for accelerator applications

    International Nuclear Information System (INIS)

    Androsov, V.P.; Karnaukhov, I.M.; Telegin, Yu.N.

    2007-01-01

    We have performed the harmonic analysis of the steady-state coherent pulse-stacking process in a high-Q Fabry-Perot cavity. The expression for the stacked pulse shape is obtained as a function of both the laser cavity and pulse-stacking cavity parameters. We have also estimated the pulse power gains attainable in the laser-optical system of NESTOR storage ring, which is under development at Kharkov Institute of Physics and Technology. It is shown that high power gains (∼10 4 ) can be, in principle, achieved in a cavity, formed with low-absorption, high reflectivity (R ∼ 0.9999) mirrors, if the laser cavity length will differ exactly by half wavelength from the pulse-stacking cavity length. It implies development of the sophisticated frequency stabilization loop for maintaining the cavity length constant within a sub-nanometer range. At the same time, power gains of ∼10 3 can be obtained with medium reflectivity mirrors (R ∼ 0.999) at considerably lower cost

  9. UV-VUV FEL program at DUKE storage ring with OK-4 optical klystron

    International Nuclear Information System (INIS)

    Litvinenko, V.N.; Madey, J.M.J.; Vinokurov, N.A.

    1993-01-01

    A 1 GeV electron storage ring dedicated for UV-VUV FEL operation is under construction at the Duke University Free Electron Laser Laboratory. The UV-VUV-FEL project, based on the collaboration of the Duke FEL Laboratory and Budker Institute for Nuclear Physics is described. The main parameters of the DFELL storage ring, of the OK-4 optical klystron, and the experimental set-up are presented. The parameters of UV-VUV FEL are given and the possible future upgrades to this system are discussed

  10. Optical surface properties and their RF limitations of European XFEL cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wenskat, Marc

    2017-04-15

    The inner surface of superconducting cavities plays a crucial role to achieve highest accelerating fields and low losses. The industrial fabrication of cavities for the European X-Ray Free Electron Laser (XFEL) and the International Linear Collider (ILC) HiGrade Research Project allowed for an investigation of this interplay. For the serial inspection of the inner surface, the optical inspection robot OBACHT was constructed and to analyze the large amount of data, represented in the images of the inner surface, an image processing and analysis code was developed and new variables to describe the cavity surface were obtained. This quantitative analysis identified vendor specific surface properties which allow to perform a quality control and assurance during the production. In addition, a strong negative correlation of ρ=-0.93 with a significance of 6σ of the integrated grain boundary area ΣA versus the maximal achievable accelerating field E{sub acc,max} has been found.

  11. Optical surface properties and their RF limitations of European XFEL cavities

    International Nuclear Information System (INIS)

    Wenskat, Marc

    2017-04-01

    The inner surface of superconducting cavities plays a crucial role to achieve highest accelerating fields and low losses. The industrial fabrication of cavities for the European X-Ray Free Electron Laser (XFEL) and the International Linear Collider (ILC) HiGrade Research Project allowed for an investigation of this interplay. For the serial inspection of the inner surface, the optical inspection robot OBACHT was constructed and to analyze the large amount of data, represented in the images of the inner surface, an image processing and analysis code was developed and new variables to describe the cavity surface were obtained. This quantitative analysis identified vendor specific surface properties which allow to perform a quality control and assurance during the production. In addition, a strong negative correlation of ρ=-0.93 with a significance of 6σ of the integrated grain boundary area ΣA versus the maximal achievable accelerating field E acc,max has been found.

  12. Photon-Mediated Quantum Gate between Two Neutral Atoms in an Optical Cavity

    Science.gov (United States)

    Welte, Stephan; Hacker, Bastian; Daiss, Severin; Ritter, Stephan; Rempe, Gerhard

    2018-02-01

    Quantum logic gates are fundamental building blocks of quantum computers. Their integration into quantum networks requires strong qubit coupling to network channels, as can be realized with neutral atoms and optical photons in cavity quantum electrodynamics. Here we demonstrate that the long-range interaction mediated by a flying photon performs a gate between two stationary atoms inside an optical cavity from which the photon is reflected. This single step executes the gate in 2 μ s . We show an entangling operation between the two atoms by generating a Bell state with 76(2)% fidelity. The gate also operates as a cnot. We demonstrate 74.1(1.6)% overlap between the observed and the ideal gate output, limited by the state preparation fidelity of 80.2(0.8)%. As the atoms are efficiently connected to a photonic channel, our gate paves the way towards quantum networking with multiqubit nodes and the distribution of entanglement in repeater-based long-distance quantum networks.

  13. Continuous parametric feedback cooling of a single atom in an optical cavity

    Science.gov (United States)

    Sames, C.; Hamsen, C.; Chibani, H.; Altin, P. A.; Wilk, T.; Rempe, G.

    2018-05-01

    We demonstrate a feedback algorithm to cool a single neutral atom trapped inside a standing-wave optical cavity. The algorithm is based on parametric modulation of the confining potential at twice the natural oscillation frequency of the atom, in combination with fast and repetitive atomic position measurements. The latter serve to continuously adjust the modulation phase to a value for which parametric excitation of the atomic motion is avoided. Cooling is limited by the measurement backaction which decoheres the atomic motion after only a few oscillations. Nonetheless, applying this feedback scheme to an ˜5 -kHz oscillation mode increases the average storage time of a single atom in the cavity by a factor of 60 to more than 2 s. In contrast to previous feedback schemes, our algorithm is also capable of cooling a much faster ˜500 -kHz oscillation mode within just microseconds. This demonstrates that parametric cooling is a powerful technique that can be applied in all experiments where optical access is limited.

  14. Photon-Mediated Quantum Gate between Two Neutral Atoms in an Optical Cavity

    Directory of Open Access Journals (Sweden)

    Stephan Welte

    2018-02-01

    Full Text Available Quantum logic gates are fundamental building blocks of quantum computers. Their integration into quantum networks requires strong qubit coupling to network channels, as can be realized with neutral atoms and optical photons in cavity quantum electrodynamics. Here we demonstrate that the long-range interaction mediated by a flying photon performs a gate between two stationary atoms inside an optical cavity from which the photon is reflected. This single step executes the gate in 2  μs. We show an entangling operation between the two atoms by generating a Bell state with 76(2% fidelity. The gate also operates as a cnot. We demonstrate 74.1(1.6% overlap between the observed and the ideal gate output, limited by the state preparation fidelity of 80.2(0.8%. As the atoms are efficiently connected to a photonic channel, our gate paves the way towards quantum networking with multiqubit nodes and the distribution of entanglement in repeater-based long-distance quantum networks.

  15. A Many-Atom Cavity QED System with Homogeneous Atom-Cavity Coupling

    OpenAIRE

    Lee, Jongmin; Vrijsen, Geert; Teper, Igor; Hosten, Onur; Kasevich, Mark A.

    2013-01-01

    We demonstrate a many-atom-cavity system with a high-finesse dual-wavelength standing wave cavity in which all participating rubidium atoms are nearly identically coupled to a 780-nm cavity mode. This homogeneous coupling is enforced by a one-dimensional optical lattice formed by the field of a 1560-nm cavity mode.

  16. UV-sensitive optical sensors based on ITO-gallium phosphide heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Oleksandr; Hidalga-Wade, F. Javier de la; Zuniga-Islas, Carlos; Abundis Patino, Jesus H. [National Institute for Astrophysics, Optics, and Electronics (INAOE), Puebla (Mexico)

    2010-04-15

    Design and characteristics of wide-band UV sensors based on ITO/GaP heterostructures are discussed. Such sensors have perfect electrical parameters and high UV-visible sensitivity in comparison with surface-barrier structures using a semi-transparent thin metal film as an electrode. Many applications require UV sensors with an effective rejection of visible radiation and a wide temperature operating interval. For this aim, the theoretical modelling of extreme selective optical sensors with a double Ag/ITO thin film on the GaP surface, in which the thin silver film serves as a narrow bandpass filter at 320 nm, has been conducted. With this modelling the optimal thickness combination for the silver and ITO films was found for the maximum rejection of the sensitivity to visible radiation (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Optical bistability in a single-sided cavity coupled to a quantum channel

    Science.gov (United States)

    Payravi, M.; Solookinejad, Gh; Jabbari, M.; Nafar, M.; Ahmadi Sangachin, E.

    2018-06-01

    In this paper, we discuss the long wavelength optical reflection and bistable behavior of an InGaN/GaN quantum dot nanostructure coupled to a single-sided cavity. It is found that due to the presence of a strong coupling field, the reflection coefficient can be controlled at long wavelength, which is essential for adjusting the threshold of reflected optical bistability. Moreover, the phase shift features of the reflection pulse inside an electromagnetically induced transparency window are also discussed.

  18. Design and fabrication of an optical dosimeter for UV and gamma irradiation

    CERN Document Server

    Ramirez-Nino, J; Castano, V M

    1999-01-01

    A simple UV and gamma radiation optical dosimeter is presented. The organic dye degradation with radiation absorption is used to measure the radiation dose. The design, the electronic circuit, the calibration and the operation procedure are also described in detail. Finally, the results of actual applications are shown with beta-carotene in an acetone/ethanol solution utilised as an optical probe.

  19. Coherent coupling of two different semiconductor quantum dots via an optical cavity mode

    Energy Technology Data Exchange (ETDEWEB)

    Villas-Boas, Jose M. [Universidade Federal de Uberlandia (UFU), MG (Brazil). Inst. de Fisica; Laucht, Arne; Hauke, Norman; Hofbauer, Felix; Boehm, Gerhard; Kaniber, Michael; Finley, Jonathan J. [Technische Universitaet Muenchen, Garching (Germany). Walter Schottky Inst.

    2011-07-01

    Full text. We present a combined experimental and theoretical study of a strongly coupled system consisting of two spatially separated self-assembled InGaAs quantum dots and a single optical nano cavity mode. Due to their different size and strain profile, the two dots exhibit markedly different electric field dependences due to the quantum confined Stark effect. This allows us to tune them into resonance simply by changing the applied bias voltage and to independently tune them into the photonic crystal nano cavity mode. Photoluminescence measurements show a characteristic triple peak during the double anti crossing, which is a clear signature of a coherently coupled system of three quantum states. We fit the emission spectra of the coupled system to theory and are able to investigate the coupling between the two quantum dots directly via the cavity mode. Furthermore, we investigate the coupling between the two quantum dots when they are detuned from the cavity mode in a V-system where dephasing due to incoherent losses from the cavity mode can be reduced

  20. Thermally Resilient, Broadband Optical Absorber from UV to IR Derived from Carbon Nanostructures

    Science.gov (United States)

    Kaul, Anupama B.; Coles, James B.

    2012-01-01

    Optical absorber coatings have been developed from carbon-based paints, metal blacks, or glassy carbon. However, such materials are not truly black and have poor absorption characteristics at longer wavelengths. The blackness of such coatings is important to increase the accuracy of calibration targets used in radiometric imaging spectrometers since blackbody cavities are prohibitively large in size. Such coatings are also useful potentially for thermal detectors, where a broadband absorber is desired. Au-black has been a commonly used broadband optical absorber, but it is very fragile and can easily be damaged by heat and mechanical vibration. An optically efficient, thermally rugged absorber could also be beneficial for thermal solar cell applications for energy harnessing, particularly in the 350-2,500 nm spectral window. It has been demonstrated that arrays of vertically oriented carbon nanotubes (CNTs), specifically multi-walled-carbon- nanotubes (MWCNTs), are an exceptional optical absorber over a broad range of wavelengths well into the infrared (IR). The reflectance of such arrays is 100x lower compared to conventional black materials, such as Au black in the spectral window of 350-2,500 nm. Total hemispherical measurements revealed a reflectance of approximately equal to 1.7% at lambda approximately equal to 1 micrometer, and at longer wavelengths into the infrared (IR), the specular reflectance was approximately equal to 2.4% at lambda approximately equal to 7 micrometers. The previously synthesized CNTs for optical absorber applications were formed using water-assisted thermal chemical vapor deposition (CVD), which yields CNT lengths in excess of 100's of microns. Vertical alignment, deemed to be a critical feature in enabling the high optical absorption from CNT arrays, occurs primarily via the crowding effect with thermal CVD synthesized CNTs, which is generally not effective in aligning CNTs with lengths less than 10 m. Here it has been shown that the

  1. Overlapping double potential wells in a single optical microtube cavity with vernier-scale-like tuning effect

    Energy Technology Data Exchange (ETDEWEB)

    Madani, A.; Schmidt, O. G. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, 01069 Dresden (Germany); Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer Str. 70, 09107 Chemnitz (Germany); Bolaños Quiñones, V. A.; Ma, L. B., E-mail: l.ma@ifw-dresden.de; Jorgensen, M. R. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, 01069 Dresden (Germany); Miao, S. D. [Anhui Key Lab of Controllable Chemical Reaction and Material Chemical Engineering, School of Chemical Engineering, Hefei University of Technology, Tunxi Road. 193, Hefei, Anhui 230009 (China)

    2016-04-25

    Spatially and temporally overlapping double potential wells are realized in a hybrid optical microtube cavity due to the coexistence of an aggregate of luminescent quantum dots embedded in the tube wall and the cone-shaped tube's geometry. The double potential wells produce two independent sets of optical modes with different sets of mode numbers, indicating phase velocity separation for the modes overlapping at the same frequency. The overlapping mode position can be tuned by modifying the tube cavity, where these mode sets shift with different magnitudes, allowing for a vernier-scale-like tuning effect.

  2. Impact of optical feedback on current-induced polarization behavior of 1550 nm vertical-cavity surface-emitting lasers.

    Science.gov (United States)

    Deng, Tao; Wu, Zheng-Mao; Xie, Yi-Yuan; Wu, Jia-Gui; Tang, Xi; Fan, Li; Panajotov, Krassimir; Xia, Guang-Qiong

    2013-06-01

    Polarization switching (PS) between two orthogonal linearly polarized fundamental modes is experimentally observed in commercial free-running 1550 nm vertical-cavity surface-emitting lasers (VCSELs) (Raycan). The characteristics of this PS are strongly modified after introducing a polarization-preserved (PP) or polarization-orthogonal (PO) optical feedback. Under the case that the external cavity is approximately 30 cm, the PP optical feedback results in the PS point shifting toward a lower injection current, and the region within which the two polarization modes coexist is enlarged with the increase of the PP feedback strength. Under too-strong PP feedback levels, the PS disappears. The impact of PO optical feedback on VCSEL polarization behavior is quite similar to that of PP optical feedback, but larger feedback strength is needed to obtain similar results.

  3. The role of local heating in the formation process of UV written optical waveguides

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Harpøth, Anders; Andersen, Marc

    2005-01-01

    A behavior is reported where the index change process used for UV writing of integrated optical waveguides in deuterium loaded Ge:SiO2 glass can become unstable and suddenly switch off or on. It is shown that such discontinuities are associated with abrupt changes in the amount of absorbed UV power...

  4. Design of a compact high-speed optical modulator based on a hybrid plasmonic nanobeam cavity

    Science.gov (United States)

    Javid, Mohammad Reza; Miri, Mehdi; Zarifkar, Abbas

    2018-03-01

    A hybrid plasmonic electro-optic modulator based on a polymer-filled one dimensional photonic crystal nanobeam (1D PhCNB) cavity is proposed here. In the proposed structure the optical intensity modulation is realized by shifting the resonant wavelength of the cavity through electrically tuning the refractive index of the electro-optic polymer in the hybrid plasmonic waveguide. As a result of the subwavelength light confinement in the hybrid plasmonic waveguide and the compact footprint of the 1D PhCNB cavity, the designed modulator has the small overall footprint of 3 . 6 μm2 and the required wavelength shift can be achieved by applying very small actuating power. Three dimensional finite-difference time-domain (3D-FDTD) simulations show that the modulation depth of 10.9 dB, and insertion loss of 1.14 dB, along with very high modulation speed of 224 GHz can be achieved in the proposed modulator with very low modulation energy of 0.75 fJ/bit. A comparison between the performance parameters of the proposed modulator and those of previously reported PhCNB based modulators reveals the superior performance of the proposed structure in terms of modulation speed, energy consumption and overall footprint.

  5. Low-photon-number optical switch and AND/OR logic gates based on quantum dot-bimodal cavity coupling system.

    Science.gov (United States)

    Ma, Shen; Ye, Han; Yu, Zhong-Yuan; Zhang, Wen; Peng, Yi-Wei; Cheng, Xiang; Liu, Yu-Min

    2016-01-11

    We propose a new scheme based on quantum dot-bimodal cavity coupling system to realize all-optical switch and logic gates in low-photon-number regime. Suppression of mode transmission due to the destructive interference effect is theoretically demonstrated by driving the cavity with two orthogonally polarized pulsed lasers at certain pulse delay. The transmitted mode can be selected by designing laser pulse sequence. The optical switch with high on-off ratio emerges when considering one driving laser as the control. Moreover, the AND/OR logic gates based on photon polarization are achieved by cascading the coupling system. Both proposed optical switch and logic gates work well in ultra-low energy magnitude. Our work may enable various applications of all-optical computing and quantum information processing.

  6. Use of gas-phase ethanol to mitigate extreme UV/water oxidation of extreme UV optics

    Science.gov (United States)

    Klebanoff, L. E.; Malinowski, M. E.; Clift, W. M.; Steinhaus, C.; Grunow, P.

    2004-03-01

    A technique is described that uses a gas-phase species to mitigate the oxidation of a Mo/Si multilayer optic caused by either extreme UV (EUV) or electron-induced dissociation of adsorbed water vapor. It is found that introduction of ethanol (EtOH) into a water-rich gas-phase environment inhibits oxidation of the outermost Si layer of the Mo/Si EUV reflective coating. Auger electron spectroscopy, sputter Auger depth profiling, EUV reflectivity, and photocurrent measurements are presented that reveal the EUV/water- and electron/water-derived optic oxidation can be suppressed at the water partial pressures used in the tests (~2×10-7-2×10-5 Torr). The ethanol appears to function differently in two time regimes. At early times, ethanol decomposes on the optic surface, providing reactive carbon atoms that scavenge reactive oxygen atoms before they can oxidize the outermost Si layer. At later times, the reactive carbon atoms form a thin (~5 Å), possibly self-limited, graphitic layer that inhibits water adsorption on the optic surface. .

  7. Maximally entangled mixed states of two atoms trapped inside an optical cavity

    International Nuclear Information System (INIS)

    Li Shangbin; Xu Jingbo

    2009-01-01

    In some off-resonant cases, the reduced density matrix of two atoms symmetrically coupled with an optical cavity can very approximately approach maximally entangled mixed states or maximal Bell violation mixed states in their evolution. The influence of a phase decoherence on the generation of a maximally entangled mixed state is also discussed

  8. Study of thermally-induced optical bistability and the role of surface treatments in Si-based mid-infrared photonic crystal cavities.

    Science.gov (United States)

    Shankar, Raji; Bulu, Irfan; Leijssen, Rick; Lončar, Marko

    2011-11-21

    We report the observation of optical bistability in Si-based photonic crystal cavities operating around 4.5 µm. Time domain measurements indicate that the source of this optical bistability is thermal, with a time constant on the order of 5 µs. Quality (Q) factor improvement is shown by the use of surface treatments (wet processes and annealing), resulting in a significant increase in Q-factor, which in our best devices is on the order of ~45,000 at 4.48 µm. After annealing in a N(2) environment, optical bistability is no longer seen in our cavities. © 2011 Optical Society of America

  9. REST-FRAME UV VERSUS OPTICAL MORPHOLOGIES OF GALAXIES USING SERSIC PROFILE FITTING: THE IMPORTANCE OF MORPHOLOGICAL K-CORRECTION

    International Nuclear Information System (INIS)

    Rawat, Abhishek; Wadadekar, Yogesh; De Mello, Duilia

    2009-01-01

    We show a comparison of the rest-frame UV morphologies of a sample of 162 intermediate-redshift (z median = 1.02) galaxies with their rest-frame optical morphologies. We select our sample from the deepest near-UV image obtained with the Hubble Space Telescope (HST) using the Wide Field Planetary Camera 2 (WFPC2; F300W) as part of the parallel observations of the Hubble Ultra Deep Field campaign overlapping with the HST/ACS Great Observatories Origins Deep Survey data set. We perform single-component Sersic fits in both WFPC2/F300W (rest-frame UV) and ACS/F850LP (rest-frame optical) bands and deduce that the Sersic index n is estimated to be smaller in the rest-frame UV compared to the rest-frame optical, leading to an overestimation of the number of merger candidates by ∼40%-100% compared to the rest-frame optical depending upon the cutoff in n employed for identifying merger candidates. This effect seems to be dominated by galaxies with low values of n(F300W) ≤ 0.5 that have a value of n(F850LP) ∼ 1.0. We argue that these objects are probably clumpy star-forming galaxies or minor mergers, both of which are essentially contaminants, if one is interested in identifying major mergers. In addition, we also find evidence that the axis ratio b/a is lower, i.e., ellipticity (1 - b/a) is higher in rest-frame UV compared to the rest-frame optical. Moreover, we find that in the rest-frame UV, the number of high ellipticity (e ≥ 0.8) objects are higher by a factor of ∼2.8 compared to the rest-frame optical. This indicates that the reported dominance of elongated morphologies among high-z Lyman Break Galaxies might just be a bias related to the use of rest-frame UV data sets in high-z studies.

  10. Cavity-enhanced spectroscopy and sensing

    Energy Technology Data Exchange (ETDEWEB)

    Gagliardi, Gianluca [CNR-Istituto Nazionale di Ottica (INO), Pozzuoli (Italy); Loock, Hans-Peter (ed.) [Queen' s Univ., Kingston, ON (Canada). Dept. of Chemistry

    2014-07-01

    The book reviews the dramatic recent advances in the use of optical resonators for high sensitivity and high resolution molecular spectroscopy as well as for chemical, mechanical and physical sensing. It encompasses a variety of cavities including those made of two or more mirrors, optical fiber loops, fiber gratings and spherical cavities. The book focuses on novel techniques and their applications. Each chapter is written by an expert and/or pioneer in the field. These experts also provide the theoretical background in optics and molecular physics where needed. Examples of recent breakthroughs include the use of frequency combs (Nobel prize 2005) for cavity enhanced sensing and spectroscopy, the use of novel cavity materials and geometries, the development of optical heterodyne detection techniques combined to active frequency-locking schemes. These methods allow the use and interrogation of optical resonators with a variety of coherent light sources for trace gas detection and sensing of strain, temperature and pressure.

  11. Cavity-enhanced spectroscopy and sensing

    CERN Document Server

    Loock, Hans-Peter

    2014-01-01

    The book reviews the dramatic recent advances in the use of optical resonators for high sensitivity and high resolution molecular spectroscopy as well as for chemical, mechanical and physical sensing.  It encompasses a variety of cavities including those made of two or more mirrors, optical fiber loops, fiber gratings and spherical cavities. The book focuses on novel techniques and their applications. Each chapter is written by an expert and/or pioneer in the field. These experts also provide the theoretical background in optics and molecular physics where needed. Examples of recent breakthroughs include the use of frequency combs (Nobel prize 2005) for cavity enhanced sensing and spectroscopy, the use of novel cavity materials and geometries, the development of optical heterodyne detection techniques combined to active frequency-locking schemes. These methods allow the use and interrogation of optical resonators with a variety of coherent light sources for trace gas detection and sensing of strain, temperat...

  12. Ultrafast Optics: Vector Cavity Fiber Lasers - Physics and Technology

    Science.gov (United States)

    2016-06-14

    with a quasi- vector cavity both numerically and experimentally. It is expected that through the study a deep and comprehensive understanding on the...799-801, Jun. 1997. 31. L. M. Zhao, D. Y. Tang, J. Wu, X. Q. Fu, and S. C. Wen , "Noise-like pulse in a gain-guided soliton fiber laser," Opt...solitons in a ring fiber laser," Optics Communications 281 (22), 5614 (2008). 110. L. M. Zhao, D. Y. Tang, J. Wu, X. Q. Fu, and S. C. Wen , "Noise-like

  13. Piezo-phototronic UV/visible photosensing with optical-fiber-nanowire hybridized structures.

    Science.gov (United States)

    Wang, Zhaona; Yu, Ruomeng; Pan, Caofeng; Liu, Ying; Ding, Yong; Wang, Zhong Lin

    2015-03-04

    An optical-fiber-nanowire hybridized UV-visible photodetector (PD) is reported. The PD is designed to allow direct integration in optical communication systems without requiring the use of couplers via fiber-welding technology. The PD works in two modes: axial and off-axial illumination mode. By using the piezo-phototronic effect, the performance of the PD is enhanced/optimized by up to 718% in sensitivity and 2067% in photoresponsivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 403 nm cavity ring-down measurements of brown carbon aerosol

    Science.gov (United States)

    Kwon, D.; Grassian, V. H.; Kleiber, P.; Young, M. A.

    2017-12-01

    Atmospheric aerosol influences Earth's climate by absorbing and scattering incoming solar radiation and outgoing terrestrial radiation. One class of secondary organic aerosol (SOA), called brown carbon (BrC), has attracted attention for its wavelength dependent light absorbing properties with absorption coefficients that generally increase from the visible (Vis) to ultraviolet (UV) regions. Here we report results from our investigation of the optical properties of BrC aerosol products from the aqueous phase reaction of ammonium sulfate (AS) with methylglyoxal (MG) using cavity ring-down spectroscopy (CRDS) at 403 nm wavelength. We have measured the optical constants of BrC SOA from the AS/MG reaction as a function of reaction time. Under dry flow conditions, we observed no apparent variation in the BrC refractive index with aging over the course of 22 days. The retrieved BrC optical constants are similar to those of AS with n = 1.52 for the real component. Despite significant UV absorption observed from the bulk BrC solution, the imaginary index value at 403 nm is below our minimum detection limit which puts an upper bound of k as 0.03. These observations are in agreement with results from our recent studies of the light scattering properties of this BrC aerosol.

  15. Two ions coupled to an optical cavity : from an enhanced quantum computer interface towards distributed quantum computing

    International Nuclear Information System (INIS)

    Casabone, B.

    2015-01-01

    Distributed quantum computing, an approach to scale up the computational power of quantum computers, requires entanglement between nodes of a quantum network. In our research group, two building blocks of schemes to entangle two ion-based quantum computers using cavity-based quantum interfaces have recently been demonstrated: ion-photon entanglement and ion-photon state mapping. In this thesis work, we extend the first building block in order to entangle two ions located in the same optical cavity. The entanglement generated by this protocol is efficient and heralded, and as it does not rely on the fact that ions interact with the same cavity, our results are a stepping stone towards the efficient generation of entanglement of remote ion-based quantum computers. In the second part of this thesis, we discuss how collective effects can be used to improve the performance of a cavity-based quantum interface. We show that by using two ions in the so-called superradiant state, the coupling strength between the two ions and the optical cavity is effectively increased compared to the single-ion case. As a complementary result, the creation of a state of two ions that exhibits a reduced coupling strength to the optical cavity, i.e., a subradiant state, is shown. Finally, we demonstrate a direct application of the increased coupling strength that the superradiant state exhibits by showing an enhanced version of the ion-photon state mapping process. By using the current setup and a second one that is being assembled, we intend to build a quantum network. The heralded ion-ion entanglement protocol presented in this thesis work will be used to entangle ions located in both setups, an experiment that requires photons generated in both apparatuses to be indistinguishable. Collective effects then can be used to modify the waveform of photons exiting the cavity in order to effect the desired photon indistinguishability. (author) [de

  16. Quantum-optical magnets with competing short- and long-range interactions: Rydberg-dressed spin lattice in an optical cavity

    Directory of Open Access Journals (Sweden)

    Jan Gelhausen, Michael Buchhold, Achim Rosch, Philipp Strack

    2016-10-01

    Full Text Available The fields of quantum simulation with cold atoms [1] and quantum optics [2] are currently being merged. In a set of recent pathbreaking experiments with atoms in optical cavities [3,4] lattice quantum many-body systems with both, a short-range interaction and a strong interaction potential of infinite range -mediated by a quantized optical light field- were realized. A theoretical modelling of these systems faces considerable complexity at the interface of: (i spontaneous symmetry-breaking and emergent phases of interacting many-body systems with a large number of atoms $N\\rightarrow\\infty$, (ii quantum optics and the dynamics of fluctuating light fields, and (iii non-equilibrium physics of driven, open quantum systems. Here we propose what is possibly the simplest, quantum-optical magnet with competing short- and long-range interactions, in which all three elements can be analyzed comprehensively: a Rydberg-dressed spin lattice [5] coherently coupled to a single photon mode. Solving a set of coupled even-odd sublattice Master equations for atomic spin and photon mean-field amplitudes, we find three key results. (R1: Superradiance and a coherent photon field can coexist with spontaneously broken magnetic translation symmetry. The latter is induced by the short-range nearest-neighbor interaction from weakly admixed Rydberg levels. (R2: This broken even-odd sublattice symmetry leaves its imprint in the light via a novel peak in the cavity spectrum beyond the conventional polariton modes. (R3: The combined effect of atomic spontaneous emission, drive, and interactions can lead to phases with anomalous photon number oscillations. Extensions of our work include nano-photonic crystals coupled to interacting atoms and multi-mode photon dynamics in Rydberg systems.

  17. Efficient continuous-wave eye-safe region signal output from intra-cavity singly resonant optical parametric oscillator

    International Nuclear Information System (INIS)

    Li Bin; Ding Xin; Sheng Quan; Yin Su-Jia; Shi Chun-Peng; Li Xue; Wen Wu-Qi; Yao Jian-Quan; Yu Xuan-Yi

    2012-01-01

    We report an efficient continuous-wave (CW) tunable intra-cavity singly resonant optical parametric oscillator based on the multi-period periodically poled lithium niobate and using a laser diode (LD) end-pumped CW 1064 nm Nd:YVO 4 laser as the pump source. A highly efficiency CW operation is realized through a careful cavity design for mode matching and thermal stability. The signal tuning range is 1401–1500 nm obtained by varying the domain period. The maximum output power of 2.2 W at 1500 nm is obtained with a 17.1 W 808 nm LD power and the corresponding conversion efficiency is 12.9%. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  18. Stacked optical antennas for plasmon propagation in a 5 nm-confined cavity

    KAUST Repository

    Saeed, A.; Panaro, S.; Zaccaria, R. Proietti; Raja, W.; Liberale, Carlo; Dipalo, M.; Messina, G. C.; Wang, H.; De Angelis, F.; Toma, A.

    2015-01-01

    The sub-wavelength concentration and propagation of electromagnetic energy are two complementary aspects of plasmonics that are not necessarily co-present in a single nanosystem. Here we exploit the strong nanofocusing properties of stacked optical antennas in order to highly concentrate the electromagnetic energy into a 5nm metal-insulator-metal (MIM) cavity and convert free radiation into guided modes. The proposed nano-architecture combines the concentration properties of optical nanoantennas with the propagation capability of MIM systems, paving the way to highly miniaturized on-chip plasmonic waveguiding. © 2015, Nature Publishing Group. All rights reserved.

  19. Stacked optical antennas for plasmon propagation in a 5 nm-confined cavity

    KAUST Repository

    Saeed, A.

    2015-06-09

    The sub-wavelength concentration and propagation of electromagnetic energy are two complementary aspects of plasmonics that are not necessarily co-present in a single nanosystem. Here we exploit the strong nanofocusing properties of stacked optical antennas in order to highly concentrate the electromagnetic energy into a 5nm metal-insulator-metal (MIM) cavity and convert free radiation into guided modes. The proposed nano-architecture combines the concentration properties of optical nanoantennas with the propagation capability of MIM systems, paving the way to highly miniaturized on-chip plasmonic waveguiding. © 2015, Nature Publishing Group. All rights reserved.

  20. Experimental Study of Electronic Quantum Interference, Photonic Crystal Cavity, Photonic Band Edge Effects for Optical Amplification

    Science.gov (United States)

    2016-01-26

    AFRL-RV-PS- AFRL-RV-PS- TR-2016-0003 TR-2016-0003 EXPERIMENTAL STUDY OF ELECTRONIC QUANTUM INTERFERENCE , PHOTONIC CRYSTAL CAVITY, PHOTONIC BAND...EDGE EFFECTS FOR OPTICAL AMPLIFICATION Shawn-Yu Lin Rensselaer Polytechnic Institute 110 8th Street Troy, New York 12180 26 Jan 2016 Final Report...2014 – 11 Jan 2016 4. TITLE AND SUBTITLE Experimental Study of Electronic Quantum Interference , Photonic Crystal Cavity, Photonic Band Edge Effects

  1. Optical microfiber-based photonic crystal cavity

    International Nuclear Information System (INIS)

    Yu, Yang; Sun, Yi-zhi; Li, Zhi-yuan; Ding, Wei; Andrews, Steve

    2016-01-01

    Using a focused ion beam milling technique, we fabricate broad stop band (∼10% wide) photonic crystal (PhC) cavities in adiabatically-tapered silica fibers. Abrupt structural design of PhC mirrors efficiently reduces radiation loss, increasing the cavity finesse to ∼7.5. Further experiments and simulations verify that the remaining loss is mainly due to Ga ion implantation. Such a microfiber PhC cavity probably has potentials in many light-matter interaction applications. (paper)

  2. Constructions of secure entanglement channels assisted by quantum dots inside single-sided optical cavities

    Science.gov (United States)

    Heo, Jino; Kang, Min-Sung; Hong, Chang-Ho; Choi, Seong-Gon; Hong, Jong-Phil

    2017-08-01

    We propose quantum information processing schemes to generate and swap entangled states based on the interactions between flying photons and quantum dots (QDs) confined within optical cavities for quantum communication. To produce and distribute entangled states (Bell and Greenberger-Horne-Zeilinger [GHZ] states) between the photonic qubits of flying photons of consumers (Alice and Bob) and electron-spin qubits of a provider (trust center, or TC), the TC employs the interactions of the QD-cavity system, which is composed of a charged QD (negatively charged exciton) inside a single-sided cavity. Subsequently, the TC constructs an entanglement channel (Bell state and 4-qubit GHZ state) to link one consumer with another through entanglement swapping, which can be realized to exploit a probe photon with interactions of the QD-cavity systems and single-qubit measurements without Bell state measurement, for quantum communication between consumers. Consequently, the TC, which has quantum nodes (QD-cavity systems), can accomplish constructing the entanglement channel (authenticated channel) between two separated consumers from the distributions of entangled states and entanglement swapping. Furthermore, our schemes using QD-cavity systems, which are feasible with a certain probability of success and high fidelity, can be experimentally implemented with technology currently in use.

  3. Composite cavity based fiber optic Fabry–Perot strain sensors demodulated by an unbalanced fiber optic Michelson interferometer with an electrical scanning mirror

    International Nuclear Information System (INIS)

    Zhang, Jianzhong; Yang, Jun; Sun, Weimin; Yuan, Libo; Jin, Wencai; Peng, G D

    2008-01-01

    A composite cavity based fiber optic Fabry–Perot strain sensor system, interrogated by a white light source and demodulated by an unbalanced fiber optic Michelson interferometer with an electrical scanning mirror, is proposed and demonstrated. Comparing with the traditional extrinsic fiber optic Fabry–Perot strain sensor, the potential multiplexing capability and the dynamic measurement range are improved simultaneously. At the same time, the measurement stability of the electrical scanning mirror system is improved by the self-referenced signal of the sensor structure

  4. Coupling of erbium dopants to yttrium orthosilicate photonic crystal cavities for on-chip optical quantum memories

    Energy Technology Data Exchange (ETDEWEB)

    Miyazono, Evan; Zhong, Tian; Craiciu, Ioana; Kindem, Jonathan M.; Faraon, Andrei, E-mail: faraon@caltech.edu [T. J. Watson Laboratory of Applied Physics, California Institute of Technology, 1200 E California Blvd, Pasadena, California 91125 (United States)

    2016-01-04

    Erbium dopants in crystals exhibit highly coherent optical transitions well suited for solid-state optical quantum memories operating in the telecom band. Here, we demonstrate coupling of erbium dopant ions in yttrium orthosilicate to a photonic crystal cavity fabricated directly in the host crystal using focused ion beam milling. The coupling leads to reduction of the photoluminescence lifetime and enhancement of the optical depth in microns-long devices, which will enable on-chip quantum memories.

  5. Side- and end-illumination of polymer optical fibers in the UV region

    Science.gov (United States)

    Eckhardt, Hanns-S.; Jungling, B.; Klein, Karl-Friedrich; Poisel, Hans

    2003-07-01

    Since more than 2 decades, the polymer optical fiber (POF) based on PMMA is well known. A lot of applications were studied and initiated: in addition to data transmission, the automotive, lighting and sensor applications are of main interest. Due to the spectral attenuation and applications, light-sources like broadband metal-halide lamps and halogen lamps, or LEDs and laser-diodes are mainly used. Due to improvement in manufacturing of the standard step-index POF, the variations of the spectral attenuation in the blue region have been reduced. Therefore, the losses are acceptable for short-length applications in the UV-A region. Using different light-sources like high-power Xenon-lamp, deuterium-lamp or UV-LEDs, the UV-damage is an important factor. In addition to the basic attenuation, the UV-induced losses will be determined by experiment, in the interesting UV-A region. The higher flexibilty of the thick-core POF is superior in comparison to silica or glass fibers with the same outer diameter. Therefore, the bending losses in the UV-region are important, too. For special applications in the medical field, side-illuminating fibers are highly accepted. The axial and spectral dependence on the lateral radiation pattern will be described, using a very thick fiber.

  6. Cavity QED experiments with ion Coulomb crystals

    DEFF Research Database (Denmark)

    Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan

    2009-01-01

    Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained.......Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained....

  7. Collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities

    Science.gov (United States)

    Lang, J.; Piazza, F.; Zwerger, W.

    2017-12-01

    We discuss the nature of symmetry breaking and the associated collective excitations for a system of bosons coupled to the electromagnetic field of two optical cavities. For the specific configuration realized in a recent experiment at ETH [1, 2], we show that, in absence of direct intercavity scattering and for parameters chosen such that the atoms couple symmetrically to both cavities, the system possesses an approximate U(1) symmetry which holds asymptotically for vanishing cavity field intensity. It corresponds to the invariance with respect to redistributing the total intensity I={I}1+{I}2 between the two cavities. The spontaneous breaking of this symmetry gives rise to a broken continuous translation-invariance for the atoms, creating a supersolid-like order in the presence of a Bose-Einstein condensate. In particular, we show that atom-mediated scattering between the two cavities, which favors the state with equal light intensities {I}1={I}2 and reduces the symmetry to {{Z}}2\\otimes {{Z}}2, gives rise to a finite value ˜ \\sqrt{I} of the effective Goldstone mass. For strong atom driving, this low energy mode is clearly separated from an effective Higgs excitation associated with changes of the total intensity I. In addition, we compute the spectral distribution of the cavity light field and show that both the Higgs and Goldstone mode acquire a finite lifetime due to Landau damping at non-zero temperature.

  8. Cavity electromagnetically induced transparency and all-optical switching using ion Coulomb crystals

    DEFF Research Database (Denmark)

    Albert, Magnus; Dantan, Aurelien Romain; Drewsen, Michael

    2011-01-01

    The control of one light field by another, ultimately at the single photon level1, 2, 3, 4, 5, 6, 7, is a challenging task that has numerous interesting applications within nonlinear optics4, 5 and quantum information science6, 7, 8. This type of control can only be achieved through highly...... nonlinear interactions, such as those based on electromagnetic induced transparency (EIT)2, 3, 4, 5, 6, 9, 10, 11, 12. Here, we demonstrate for the first time EIT as well as all-optical EIT-based light switching using ion Coulomb crystals situated in an optical cavity. Changes from essentially full...... milestones for future realizations of quantum information processing devices, such as high-efficiency quantum memories8, 13, 14, single-photon transistors15, 16 and single-photon gates4, 6, 9....

  9. Energy Pooling Upconversion in Free Space and Optical Cavities

    Science.gov (United States)

    LaCount, Michael D.

    energy pooling rate efficiency of 99%. This demonstrates that the energy pooling rate can be made faster than its competing processes. Based on the results of this study, a set of design rules was developed to optimize the rate efficiency of energy pooling. Prior to this research, no attempt had been made to determine if energy pooling could be made to out-pace competing processes--i.e. whether or not a molecular system could be designed to utilize energy pooling as an efficient means of upconversion. This initial investigation was part of a larger effort involving a team of researchers at the University of Colorado, Boulder and at the National Renewable Energy Laboratory. After establishing our computational proof-of-concept, we collectively used the new design rules to select an improved system for energy pooling. This consisted of rhodamine 6G and stilbene-420. These molecules were fabricated into a thin film, and the maximum internal quantum yield was measured to be 36% under sufficiently high intensity light. To further increase the efficiency of energy pooling, encapsulation within optical cavities was considered as a way of changing the rate of processes characterized by electric dipole-dipole coupling. This was carried out using a combination of classical electromagnetism, quantum electrodynamics, and perturbation theory. It was found that, in the near field, if the distance of the energy transfer is smaller than the distance from the energy transfer site and the cavity wall, then the electric dipole-dipole coupling tensor is not influenced by the cavity environment and the rates of energy transfer processes are the same as those in free space. Any increase in energy transfer efficiencies that are experimentally measured must therefore be caused by changing the rate of light absorption and emission. This is an important finding because earlier, less rigorous studies had concluded otherwise. It has been previously demonstrated that an optical cavity can be used to

  10. Mesoscale cavities in hollow-core waveguides for quantum optics with atomic ensembles

    Directory of Open Access Journals (Sweden)

    Haapamaki C.M.

    2016-08-01

    Full Text Available Single-mode hollow-core waveguides loaded with atomic ensembles offer an excellent platform for light–matter interactions and nonlinear optics at low photon levels. We review and discuss possible approaches for incorporating mirrors, cavities, and Bragg gratings into these waveguides without obstructing their hollow cores. With these additional features controlling the light propagation in the hollow-core waveguides, one could potentially achieve optical nonlinearities controllable by single photons in systems with small footprints that can be integrated on a chip. We propose possible applications such as single-photon transistors and superradiant lasers that could be implemented in these enhanced hollow-core waveguides.

  11. High-Speed Semiconductor Vertical-Cavity Surface-Emitting Lasers for Optical Data-Transmission Systems (Review)

    Science.gov (United States)

    Blokhin, S. A.; Maleev, N. A.; Bobrov, M. A.; Kuzmenkov, A. G.; Sakharov, A. V.; Ustinov, V. M.

    2018-01-01

    The main problems of providing a high-speed operation semiconductor lasers with a vertical microcavity (so-called "vertical-cavity surface-emitting lasers") under amplitude modulation and ways to solve them have been considered. The influence of the internal properties of the radiating active region and the electrical parasitic elements of the equivalent circuit of lasers are discussed. An overview of approaches that lead to an increase of the cutoff parasitic frequency, an increase of the differential gain of the active region, the possibility of the management of mode emission composition and the lifetime of photons in the optical microcavities, and reduction of the influence of thermal effects have been presented. The achieved level of modulation bandwidth of ˜30 GHz is close to the maximum achievable for the classical scheme of the direct-current modulation, which makes it necessary to use a multilevel modulation format to further increase the information capacity of optical channels constructed on the basis of vertical-cavity surface-emitting lasers.

  12. Penetration of UV-A, UV-B, blue, and red light into leaf tissues of pecan measured by a fiber optic microprobe system

    Science.gov (United States)

    Qi, Yadong; Bai, Shuju; Vogelmann, Thomas C.; Heisler, Gordon M.

    2003-11-01

    The depth of light penetration from the adaxial surfaces of the mature leaves of pecan (Carya illinoensis) was measured using a fiber optic microprobe system at four wavelengths: UV-B (310nm), UV-A (360 nm), blue light (430nm), and red light (680nm). The average thickness of the leaf adaxial epidermal layer was 15um and the total leaf thickness was 219um. The patterns of the light attenuation by the leaf tissues exhibited strong wavelength dependence. The leaf adaxial epidermal layer was chiefly responsible for absorbing the UV-A UV-B radiation. About 98% of 310 nm light was steeply attenuated within the first 5 um of the adaxial epidermis; thus, very little UV-B radiation was transmitted to the mesophyll tissues where contain photosynthetically sensitive sites. The adaxial epidermis also attenuated 96% of the UV-A radiation. In contrast, the blue and red light penetrated much deeper and was gradually attenutated by the leaves. The mesophyll tissues attenuated 17% of the blue light and 42% of the red light, which were available for photosynthesis use. Since the epidermal layer absorbed nearly all UV-B light, it acted as an effective filter screening out the harmful radiation and protecting photosynthetically sensitive tissues from the UV-B damage. Therefore, the epidermal function of the UV-B screening effectiveness can be regarded as one of the UV-B protection mechanisms in pecan.

  13. Simultaneous cooling and entanglement of mechanical modes of a micromirror in an optical cavity

    International Nuclear Information System (INIS)

    Genes, Claudiu; Vitali, David; Tombesi, Paolo

    2008-01-01

    Laser cooling of a mechanical mode of a resonator by the radiation pressure of a detuned optical cavity mode has been recently demonstrated by various groups in different experimental configurations. Here, we consider the effect of a second mechanical mode with a close but different resonance frequency. We show that the nearby mechanical resonance is simultaneously cooled by the cavity field, provided that the difference between the two mechanical frequencies is not too small. When this frequency difference becomes smaller than the effective mechanical damping of the secondary mode, the two cooling processes interfere destructively similarly to what happens in electromagnetically induced transparency, and cavity cooling is suppressed in the limit of identical mechanical frequencies. We show that also the entanglement properties of the steady state of the tripartite system crucially depend upon the difference between the two mechanical frequencies. If the latter is larger than the effective damping of the second mechanical mode, the state shows fully tripartite entanglement and each mechanical mode is entangled with the cavity mode. If instead, the frequency difference is smaller, the steady state is a two-mode biseparable state, inseparable only when one splits the cavity mode from the two mechanical modes. In this latter case, the entanglement of each mechanical mode with the cavity mode is extremely fragile with respect to temperature.

  14. Hollow waveguide cavity ringdown spectroscopy

    Science.gov (United States)

    Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

    2012-01-01

    Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

  15. Non-destructive evaluation of UV pulse laser-induced damage performance of fused silica optics.

    Science.gov (United States)

    Huang, Jin; Wang, Fengrui; Liu, Hongjie; Geng, Feng; Jiang, Xiaodong; Sun, Laixi; Ye, Xin; Li, Qingzhi; Wu, Weidong; Zheng, Wanguo; Sun, Dunlu

    2017-11-24

    The surface laser damage performance of fused silica optics is related to the distribution of surface defects. In this study, we used chemical etching assisted by ultrasound and magnetorheological finishing to modify defect distribution in a fused silica surface, resulting in fused silica samples with different laser damage performance. Non-destructive test methods such as UV laser-induced fluorescence imaging and photo-thermal deflection were used to characterize the surface defects that contribute to the absorption of UV laser radiation. Our results indicate that the two methods can quantitatively distinguish differences in the distribution of absorptive defects in fused silica samples subjected to different post-processing steps. The percentage of fluorescence defects and the weak absorption coefficient were strongly related to the damage threshold and damage density of fused silica optics, as confirmed by the correlation curves built from statistical analysis of experimental data. The results show that non-destructive evaluation methods such as laser-induced fluorescence and photo-thermal absorption can be effectively applied to estimate the damage performance of fused silica optics at 351 nm pulse laser radiation. This indirect evaluation method is effective for laser damage performance assessment of fused silica optics prior to utilization.

  16. Investigations of repetition rate stability of a mode-locked quantum dot semiconductor laser in an auxiliary optical fiber cavity

    DEFF Research Database (Denmark)

    Breuer, Stefan; Elsässer, Wolfgang; McInerney, J.G.

    2010-01-01

    We have investigated experimentally the pulse train (mode beating) stability of a monolithic mode-locked multi-section quantum-dot laser with an added passive auxiliary optical fiber cavity. Addition of the weakly coupled (¿ -24dB) cavity reduces the current-induced shift d¿/dI of the principal...

  17. Quantum state engineering, purification, and number-resolved photon detection with high-finesse optical cavities

    DEFF Research Database (Denmark)

    Nielsen, Anne E. B.; Muschik, Christine A.; Giedke, Geza

    2010-01-01

    We propose and analyze a multifunctional setup consisting of high-finesse optical cavities, beam splitters, and phase shifters. The basic scheme projects arbitrary photonic two-mode input states onto the subspace spanned by the product of Fock states |n>|n> with n=0,1,2,.... This protocol does no...... is especially attractive as a generalization to many modes allows for distribution and purification of entanglement in networks. In an alternative working mode, the setup allows for quantum nondemolition number resolved photodetection in the optical domain....

  18. Quantum noise of a Bose-Einstein condensate in an optical cavity, correlations, and entanglement

    International Nuclear Information System (INIS)

    Szirmai, G.; Nagy, D.; Domokos, P.

    2010-01-01

    A Bose-Einstein condensate of ultracold atoms inside the field of a laser-driven optical cavity exhibits dispersive optical bistability. We describe this system by using mean-field approximation and by analyzing the correlation functions of the linearized quantum fluctuations around the mean-field solution. The entanglement and the statistics of the atom-field quadratures are given in the stationary state. It is shown that the mean-field solution, that is, the Bose-Einstein condensate, is robust against entanglement generation for most of the phase diagram.

  19. Quantum noise of a Bose-Einstein condensate in an optical cavity, correlations, and entanglement

    Science.gov (United States)

    Szirmai, G.; Nagy, D.; Domokos, P.

    2010-04-01

    A Bose-Einstein condensate of ultracold atoms inside the field of a laser-driven optical cavity exhibits dispersive optical bistability. We describe this system by using mean-field approximation and by analyzing the correlation functions of the linearized quantum fluctuations around the mean-field solution. The entanglement and the statistics of the atom-field quadratures are given in the stationary state. It is shown that the mean-field solution, that is, the Bose-Einstein condensate, is robust against entanglement generation for most of the phase diagram.

  20. Readout of the UFFO Slewing Mirror Telescope to detect UV/optical photons from Gamma-Ray Bursts

    DEFF Research Database (Denmark)

    Kim, J. E.; Lim, H.; Nam, J. W.

    2013-01-01

    plane detector of Intensified Charge-Coupled Device (ICCD). The ICCD is sensitive to UV/optical photons of 200–650 nm in wavelength by using a UV-enhanced S20 photocathode and amplifies photoelectrons at a gain of 104–106 in double Micro-Channel Plates. These photons are read out by a Kodak KAI-0340...

  1. Tunable high-power narrow-spectrum external-cavity diode laser at 675 nm as a pump source for UV generation

    DEFF Research Database (Denmark)

    Chi, Mingjun; Jensen, Ole Bjarlin; Erbert, Gotz

    2011-01-01

    High-power narrow-spectrum diode laser systems based on tapered gain media in external cavity are demonstrated at 675 nm. Two 2-mm-long amplifiers are used, one with a 500-µm-long ridge-waveguide section (device A), the other with a 750-µm-long ridge-waveguide section (device B). The laser system...... of 1.0 W. The laser system B based on device B is tunable from 666 to 685 nm. As high as 1.05 W output power is obtained around 675.67 nm. The emission spectral bandwidth is less than 0.07 nm throughout the tuning range, and the beam quality factor M2 is 1.13 at an output power of 0.93 W. The laser...... system B is used as a pump source for the generation of 337.6 nm UV light by single-pass frequency doubling in a BIBO crystal. An output power of 109 µW UV light, corresponding to a conversion efficiency of 0.026%W-1 is attained....

  2. Transverse UV-laser irradiation-induced defects and absorption in a single-mode erbium-doped optical fiber

    International Nuclear Information System (INIS)

    Tortech, B.; Ouerdane, Y.; Boukenter, A.; Meunier, J. P.; Girard, S.; Van Uffelen, M.; Berghmans, F.; Regnier, E.; Berghmans, F.; Thienpont, H.

    2009-01-01

    Near UV-visible absorption coefficients of an erbium-doped optical fiber were investigated through an original technique based on a transverse cw UV-laser irradiation operating at 244 nm. Such irradiation leads to the generation of a quite intense guided luminescence signal in near UV spectral range. This photoluminescence probe source combined with a longitudinal translation of the fiber sample (at a constant velocity) along the UV-laser irradiation, presents several major advantages: (i) we bypass and avoid the procedures classically used to study the radiation induced attenuation which are not adapted to our case mainly because the samples present a very strong absorption with significant difficulties due to the injection of adequate UV-light levels in a small fiber diameter: (ii) the influence of the laser irradiation on the host matrix of the optical fiber is directly correlated to the evolution of the generated photoluminescence signal and (iii) in our experimental conditions, short fiber sample lengths (typically 20-30 cm) suffice to determine the associated absorption coefficients over the entire studied spectral domain. The generated photoluminescence signal is also used to characterize the absorption of the erbium ions in the same wavelength range with no cut-back method needed. (authors)

  3. Radiation-pressure-mediated control of an optomechanical cavity

    Science.gov (United States)

    Cripe, Jonathan; Aggarwal, Nancy; Singh, Robinjeet; Lanza, Robert; Libson, Adam; Yap, Min Jet; Cole, Garrett D.; McClelland, David E.; Mavalvala, Nergis; Corbitt, Thomas

    2018-01-01

    We describe and demonstrate a method to control a detuned movable-mirror Fabry-Pérot cavity using radiation pressure in the presence of a strong optical spring. At frequencies below the optical spring resonance, self-locking of the cavity is achieved intrinsically by the optomechanical (OM) interaction between the cavity field and the movable end mirror. The OM interaction results in a high rigidity and reduced susceptibility of the mirror to external forces. However, due to a finite delay time in the cavity, this enhanced rigidity is accompanied by an antidamping force, which destabilizes the cavity. The cavity is stabilized by applying external feedback in a frequency band around the optical spring resonance. The error signal is sensed in the amplitude quadrature of the transmitted beam with a photodetector. An amplitude modulator in the input path to the cavity modulates the light intensity to provide the stabilizing radiation pressure force.

  4. Noise-Immune Cavity-Enhanced Optical Heterodyne Molecular Spectrometry Modelling Under Saturated Absorption

    Science.gov (United States)

    Dupré, Patrick

    2015-06-01

    The Noise-Immune Cavity-Enhanced Optical Heterodyne Molecular Spectrometry (NICE-OHMS) is a modern technique renowned for its ultimate sensitivity, because it combines long equivalent absorption length provided by a high finesse cavity, and a detection theoretically limited by the sole photon-shot-noise. One fallout of the high finesse is the possibility to accumulating strong intracavity electromagnetic fields (EMF). Under this condition, molecular transitions can be easy saturated giving rise to the usual Lamb dips (or hole burning). However, the unusual shape of the basically trichromatic EMF (due to the RF lateral sidebands) induces nonlinear couplings, i.e., new crossover transitions. An analytical methodology will be presented to calculate spectra provided by NICE-OHMS experiments. It is based on the solutions of the equations of motion of an open two-blocked-level system performed in the frequency-domain (optically thin medium). Knowing the transition dipole moment, the NICE-OHMS signals (``absorption-like'' and ``dispersion-like'') can be simulated by integration over the Doppler shifts and by paying attention to the molecular Zeeman sublevels and to the EMF polarization The approach has been validated by discussion experimental data obtained on two transitions of {C2H2} in the near-infrared under moderated saturation. One of the applications of the saturated absorption is to be able to simultaneously determine the transition intensity and the density number while only one these 2 quantities can only be assessed in nonlinear absorption. J. Opt. Soc. Am. B 32, 838 (2015) Optics Express 16, 14689 (2008)

  5. Fiber cavities with integrated mode matching optics.

    Science.gov (United States)

    Gulati, Gurpreet Kaur; Takahashi, Hiroki; Podoliak, Nina; Horak, Peter; Keller, Matthias

    2017-07-17

    In fiber based Fabry-Pérot Cavities (FFPCs), limited spatial mode matching between the cavity mode and input/output modes has been the main hindrance for many applications. We have demonstrated a versatile mode matching method for FFPCs. Our novel design employs an assembly of a graded-index and large core multimode fiber directly spliced to a single mode fiber. This all-fiber assembly transforms the propagating mode of the single mode fiber to match with the mode of a FFPC. As a result, we have measured a mode matching of 90% for a cavity length of ~400 μm. This is a significant improvement compared to conventional FFPCs coupled with just a single mode fiber, especially at long cavity lengths. Adjusting the parameters of the assembly, the fundamental cavity mode can be matched with the mode of almost any single mode fiber, making this approach highly versatile and integrable.

  6. Dither Cavity Length Controller with Iodine Locking

    Directory of Open Access Journals (Sweden)

    Lawson Marty

    2016-01-01

    Full Text Available A cavity length controller for a seeded Q-switched frequency doubled Nd:YAG laser is constructed. The cavity length controller uses a piezo-mirror dither voltage to find the optimum length for the seeded cavity. The piezo-mirror dither also dithers the optical frequency of the output pulse. [1]. This dither in optical frequency is then used to lock to an Iodine absorption line.

  7. Enhanced photoelastic modulation in silica phononic crystal cavities

    Science.gov (United States)

    Kim, Ingi; Iwamoto, Satoshi; Arakawa, Yasuhiko

    2018-04-01

    The enhanced photoelastic modulation in quasi-one-dimensional (1D) phononic crystal (PnC) cavities made of fused silica is experimentally demonstrated. A confined acoustic wave in the cavity can induce a large birefringence through the photoelastic effect and enable larger optical modulation amplitude at the same acoustic power. We observe a phase retardation of ∼26 mrad of light passing through the cavity when the exciting acoustic frequency is tuned to the cavity mode resonance of ∼500 kHz at 2.5 V. In the present experiment, a 16-fold enhancement of retardation in the PnC cavity is demonstrated compared with that in a bar-shaped silica structure. Spatially resolved optical retardation measurement reveals that the large retardation is realized only around the cavity reflecting the localized nature of the acoustic cavity mode. The enhanced interactions between acoustic waves and light can be utilized to improve the performance of acousto-optic devices such as photoelastic modulators.

  8. Spectral characterization in deep UV of an improved imaging KDP acousto-optic tunable filter

    International Nuclear Information System (INIS)

    Gupta, Neelam; Voloshinov, Vitaly

    2014-01-01

    Recently, we developed a number of high quality noncollinear acousto-optic tunable filter (AOTF) cells in different birefringent materials with UV imaging capability. Cells based on a single crystal of KDP (potassium dihydrophosphate) had the best transmission efficiency and the optical throughput needed to acquire high quality spectral images at wavelengths above 220 nm. One of the main limitations of these imaging filters was their small angular aperture in air, limited to about 1.0°. In this paper, we describe an improved imaging KDP AOTF operating from the deep UV to the visible region of the spectrum. The linear and angular apertures of the new filter are 10 × 10 mm 2 and 1.8°, respectively. The spectral tuning range is 205–430 nm with a 60 cm −1 spectral resolution. We describe the filter and present experimental results on imaging using both a broadband source and a number of light emitting diodes (LEDs) in the UV, and include the measured spectra of these LEDs obtained with a collinear SiO 2 filter-based spectrometer operating above 255 nm. (paper)

  9. MID-IR LUMINOSITIES AND UV/OPTICAL STAR FORMATION RATES AT z < 1.4

    International Nuclear Information System (INIS)

    Salim, Samir; Dickinson, Mark; Michael Rich, R.; Charlot, Stephane; Lee, Janice C.; Schiminovich, David; Perez-Gonzalez, Pablo G.; Ashby, Matthew L. N.; Noeske, Kai; Papovich, Casey; Weiner, Benjamin J.; Faber, S. M.; Ivison, Rob J.; Frayer, David T.; Walton, Josiah M.; Chary, Ranga-Ram; Bundy, Kevin; Koekemoer, Anton M.

    2009-01-01

    Ultraviolet (UV) nonionizing continuum and mid-infrared (IR) emission constitute the basis of two widely used star formation (SF) indicators at intermediate and high redshifts. We study 2430 galaxies with z 10 -10 12 L sun ). We show that the IR luminosity can be estimated from the UV and optical photometry to within a factor of 2, implying that most z IR >10 11 L sun , yet with little current SF. For them a reasonable amount of dust absorption of stellar light (but presumably higher than in nearby early-type galaxies) is sufficient to produce the observed levels of IR, which includes a large contribution from intermediate and old stellar populations. In our sample, which contains very few ultraluminous IR galaxies, optical and X-ray active galactic nuclei do not contribute on average more than ∼50% to the mid-IR luminosity, and we see no evidence for a large population of 'IR excess' galaxies.

  10. Q-switched operation with Fox-Smith-Michelson laser cavity

    International Nuclear Information System (INIS)

    Huang, X; Huang, L; Gong, M

    2008-01-01

    A new kind of three-mirror composite cavity, Fox-Smith-Michelson cavity has been configured. This laser cavity is capable of high power output, owing to the low threshold of Michelson cavity. Also, thanks to the mode selection function of Fox-Smith cavity, stable pulses at high repetition rate can be generated. In our experiment, 15.54 W CW output at 1064 nm has been achieved, with an optic-to-optic conversion efficiency of 42.2%. At the Q-switching repetition rate of 100 kHz, the average output power is 11.92 W, with an optic-to-optic conversion efficiency of 38.2%. For Q-switching frequency from 30 kHz to 100 kHz, the pulse width variation is below 4.4% and the amplitude variation is below 4.8%

  11. The measurement of the optical cavity length for the infrared free electron laser

    International Nuclear Information System (INIS)

    Curtis, C.J.; Dahlberg, J.C.; Oren, W.A.; Tremblay, K.J.

    1999-01-01

    One of the final tasks involved in the alignment of the newly constructed Free Electron Laser at the Thomas Jefferson National Accelerator Facility was to accurately measure the length between two mirrors which make up the optical cavity. This presentation examines the survey techniques and equipment assembled in order to complete these measurements, together with the possible sources of error, and the accuracy achieved. (authors)

  12. Coherent coupling of two different semiconductor quantum dots via an optical cavity mode

    Energy Technology Data Exchange (ETDEWEB)

    Laucht, Arne; Villas-Boas, Jose M.; Hauke, Norman; Hofbauer, Felix; Boehm, Gerhard; Kaniber, Michael; Finley, Jonathan J. [Walter Schottky Institut, Technische Universitaet Muenchen, Garching (Germany)

    2010-07-01

    We present a combined experimental and theoretical study of a strongly coupled system consisting of two spatially separated self-assembled InGaAs quantum dots and a single optical nanocavity mode. Due to their different size and strain profile, the two dots exhibit markedly different electric field dependences due to the quantum confined Stark effect. This allows us to tune them into resonance simply by changing the applied bias voltage and to independently tune them into the photonic crystal nanocavity mode. Photoluminescence measurements show a characteristic triple peak during the double anticrossing, which is a clear signature of a coherently coupled system of three quantum states. We fit the emission spectra of the coupled system to theory and are able to investigate the coupling between the two quantum dots directly via the cavity mode. Furthermore, we investigate the coupling between the two quantum dots when they are detuned from the cavity mode in a V-system where dephasing due to incoherent losses from the cavity mode can be reduced.

  13. Observation of Fano-Type Interference in a Coupled Cavity-Atom System

    International Nuclear Information System (INIS)

    Cheng Yong; Tan Zheng; Wang Jin; Zhan Ming-Sheng; Zhu Yi-Fu

    2016-01-01

    We present the experimental observation of the Fano-type interference in a coupled cavity-atom system by confining the laser-cooled "8"5Rb atoms in an optical cavity. The asymmetric Fano profile is obtained through quantum interference in a three-level atomic system coherently coupled to a single mode cavity field. The observed Fano profile can be explained by the interference between the intra-cavity dark state and the polariton state of the coupled cavity-atom system. The possible applications of our observations include all-optical switching, optical sensing and narrow band optical filters. (paper)

  14. Transverse effects in UV FELs

    International Nuclear Information System (INIS)

    Small, D.W.; Wong, R.K.; Colson, W.B.

    1995-01-01

    In an ultraviolet Free Electron Laser (UV FEL), the electron beam size can be approximately the same as the optical mode size. The performance of a UV FEL is studied including the effect of emittance, betatron focusing, and external focusing of the electron beam on the transverse optical mode. The results are applied to the Industrial Laser Consortium's UV FEL

  15. Laser of optical fiber composed by two coupled cavities: application as optical fiber sensor; Laser de fibra optica compuesto por dos cavidades acopladas: aplicacion como sensor de fibra optica

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez S, R.A.; Kuzin, E.A.; Ibarra E, B. [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), A.P. 51 y 216, 72000 Puebla (Mexico); May A, M. [Universidad Autonoma del Carmen (UNACAR) Av. 56 No. 4 por Av. Concordia, Campeche (Mexico); Shlyagin, M.; Marquez B, I. [Centro de Investigacion Cientifica y de Ensenanza Superior de Ensenada (CICESE), 22860 Ensenada, Baja California (Mexico)]. e-mail: ravsa100@hotmail.com

    2004-07-01

    We show an optical fiber laser sensor which consist of two cavities coupled and three fiber Bragg gratings. We used one Bragg grating (called reference) and two Bragg gratings (called sensors), which have the lower reflection wavelength. The reference grating with the two sensors grating make two cavities: first one is the internal cavity which has 4230 m of length and the another one is the external cavity which has 4277 m of length. Measuring the laser beating frequency for a resonance cavity and moving the frequency peaks when the another cavity is put in resonance, we prove that the arrangement can be used as a two points sensor for determining the difference of temperature or stress between these two points. (Author)

  16. Phonon Routing in Integrated Optomechanical Cavity-waveguide Systems

    Science.gov (United States)

    2015-08-20

    cavity (bottom beam of Fig. 1b), allowing for evanescent cou- pling of laser light into and out of the cavity. A single optical fiber taper is used to...couple light into the on- chip coupling waveguide, and a photonic crystal mirror is etched in to the end of the optical coupling waveguide so that light...coupled into the nanobeam cavity can be recollected by the optical fiber taper as per Ref. [36]. Figure 1c shows the band structure of the phonon

  17. A helical optical for circular polarized UV-FEL project at the UVSOR

    Energy Technology Data Exchange (ETDEWEB)

    Hama, Hiroyuki [Institute for Molecular Science, Okazaki (Japan)

    1995-12-31

    Most of existing storage ring free electron lasers (SRFEL) are restricted those performances by degradation of mirrors in optical cavities. In general, the SRFEL gain at the short wavelength region with high energy electrons is quite low, and the high reflectivity mirrors such as dielectric multilayer mirrors are therefore required. The mirror degradation is considered as a result of irradiation of higher harmonic photons that are simultaneously emitted from planar optical klystron (OK) type undulators, which are commonly used in SRFEL. This problem is getting severer as the lasing wavelength becomes shorter. The UVSOR-FEL had been originally scheduled to be shutdown by 1996 because another undulator project for spectroscopic studies with circular polarized photon would take the FEL`s place. According to suggestion of the insertion device group of the SPring-8, we have designed a helical undulator that is able to vary degree and direction of the polarization easily. In addition, the undulator can be converted into a helical OK by replacing magnets at the center part of undulator in order to coexist with further FEL experiments. Using a calculated magnetic field for magnet configurations of the OK mode, the radiation spectrum at wide wavelength range was simulated by a Fourier transform of Lienard-Wiechert potentials. As a matter of course, some higher harmonics are radiated on the off-axis angle. However it was found out that the higher harmonics is almost negligible as far as inside a solid angle of the Gaussian laser mode. Moreover the gain at the UV region of 250 nm is expected to be much higher than our present FEL because of high brilliant fundamental radiation. The calculated spatial distribution of higher harmonics and the estimated instantaneous gain is presented. Advantages of the helical OK for SRFEL will be discussed in view of our experience, and a possibility of application two-color experiment with SR will be also mentioned.

  18. UV SEDs of early-type cluster galaxies: a new look at the UV upturn

    Science.gov (United States)

    Ali, S. S.; Bremer, M. N.; Phillipps, S.; De Propris, R.

    2018-05-01

    Using GALEX, Ultraviolet Optical Telescope (UVOT), and optical photometry, we explore the prevalence and strength of the Ultraviolet (UV) upturn in the spectra of quiescent early-type galaxies in several nearby clusters. Even for galaxies with completely passive optical colours, there is a large spread in vacuum UV colour consistent with almost all having some UV upturn component. Combining GALEX and UVOT data below 3000 Å, we generate for the first time comparatively detailed UV spectral energy distributions for Coma cluster galaxies. Fitting the UV upturn component with a blackbody, 26 of these show a range of characteristic temperatures (10 000-21 000K) for the UV upturn population. Assuming a single temperature to explain GALEX-optical colours could underestimate the fraction of galaxies with UV upturns and mis-classify some as systems with residual star formation. The UV upturn phenomenon is not an exclusive feature found only in giant galaxies; we identify galaxies with similar (or even bluer) FUV - V colours to the giants with upturns over a range of fainter luminosities. The temperature and strength of the UV upturn are correlated with galaxy mass. Under the plausible hypothesis that the sources of the UV upturn are blue horizontal branch stars, the most likely mechanism for this is the presence of a substantial (between 4 per cent and 20 per cent) Helium-rich (Y > 0.3) population of stars in these galaxies, potentially formed at z ˜ 4 and certainly at z > 2; this plausibly sets a lower limit of {˜ } {0.3- 0.8} × 10^{10} M⊙ to the in situ stellar mass of ˜L* galaxies at this redshift.

  19. Optical design for CETUS: a wide-field 1.5m aperture UV payload being studied for a NASA probe class mission study

    Science.gov (United States)

    Woodruff, Robert; Robert Woodruff, Goddard Space Flight Center, Kendrick Optical Consulting

    2018-01-01

    We are developing a NASA Headquarters selected Probe-class mission concept called the Cosmic Evolution Through UV Spectroscopy (CETUS) mission, which includes a 1.5-m aperture diameter large field-of-view (FOV) telescope optimized for UV imaging, multi-object spectroscopy, and point-source spectroscopy. The optical system includes a Three Mirror Anastigmatic (TMA) telescope that simultaneously feeds three separate scientific instruments: the near-UV (NUV) Multi-Object Spectrograph (MOS) with a next-generation Micro-Shutter Array (MSA); the two-channel camera covering the far-UV (FUV) and NUV spectrum; and the point-source spectrograph covering the FUV and NUV region with selectable R~ 40,000 echelle modes and R~ 2,000 first order modes. The optical system includes fine guidance sensors, wavefront sensing, and spectral and flat-field in-flight calibration sources. This paper will describe the current optical design of CETUS.

  20. Quantum-coherent coupling of a mechanical oscillator to an optical cavity mode.

    Science.gov (United States)

    Verhagen, E; Deléglise, S; Weis, S; Schliesser, A; Kippenberg, T J

    2012-02-01

    Optical laser fields have been widely used to achieve quantum control over the motional and internal degrees of freedom of atoms and ions, molecules and atomic gases. A route to controlling the quantum states of macroscopic mechanical oscillators in a similar fashion is to exploit the parametric coupling between optical and mechanical degrees of freedom through radiation pressure in suitably engineered optical cavities. If the optomechanical coupling is 'quantum coherent'--that is, if the coherent coupling rate exceeds both the optical and the mechanical decoherence rate--quantum states are transferred from the optical field to the mechanical oscillator and vice versa. This transfer allows control of the mechanical oscillator state using the wide range of available quantum optical techniques. So far, however, quantum-coherent coupling of micromechanical oscillators has only been achieved using microwave fields at millikelvin temperatures. Optical experiments have not attained this regime owing to the large mechanical decoherence rates and the difficulty of overcoming optical dissipation. Here we achieve quantum-coherent coupling between optical photons and a micromechanical oscillator. Simultaneously, coupling to the cold photon bath cools the mechanical oscillator to an average occupancy of 1.7 ± 0.1 motional quanta. Excitation with weak classical light pulses reveals the exchange of energy between the optical light field and the micromechanical oscillator in the time domain at the level of less than one quantum on average. This optomechanical system establishes an efficient quantum interface between mechanical oscillators and optical photons, which can provide decoherence-free transport of quantum states through optical fibres. Our results offer a route towards the use of mechanical oscillators as quantum transducers or in microwave-to-optical quantum links.

  1. Lithographic wavelength control of an external cavity laser with a silicon photonic crystal cavity-based resonant reflector.

    Science.gov (United States)

    Liles, Alexandros A; Debnath, Kapil; O'Faolain, Liam

    2016-03-01

    We report the experimental demonstration of a new design for external cavity hybrid lasers consisting of a III-V semiconductor optical amplifier (SOA) with fiber reflector and a photonic crystal (PhC)-based resonant reflector on SOI. The silicon reflector is composed of an SU8 polymer bus waveguide vertically coupled to a PhC cavity and provides a wavelength-selective optical feedback to the laser cavity. This device exhibits milliwatt-level output power and side-mode suppression ratios of more than 25 dB.

  2. Changing of optical absorption and scattering coefficients in nonlinear-optical crystal lithium triborate before and after interaction with UV-radiation

    Science.gov (United States)

    Demkin, Artem S.; Nikitin, Dmitriy G.; Ryabushkin, Oleg A.

    2016-04-01

    In current work optical properties of LiB3O5 (LBO) crystal with ultraviolet (UV) (λ= 266 nm) induced volume macroscopic defect (track) are investigated using novel piezoelectric resonance laser calorimetry technique. Pulsed laser radiation of 10 W average power at 532 nm wavelength, is consecutively focused into spatial regions with and without optical defect. For these cases exponential fitting of crystal temperature kinetics measured during its irradiation gives different optical absorption coefficients α1 = 8.1 • 10-4 cm-1 (region with defect) and α =3.9ṡ10-4 cm-1 (non-defected region). Optical scattering coefficient is determined as the difference between optical absorption coefficients measured for opaque and transparent lateral facets of the crystal respectively. Measurements reveal that scattering coefficient of LBO in the region with defect is three times higher than the optical absorption coefficient.

  3. Negative-Mass Instability of the Spin and Motion of an Atomic Gas Driven by Optical Cavity Backaction

    Science.gov (United States)

    Kohler, Jonathan; Gerber, Justin A.; Dowd, Emma; Stamper-Kurn, Dan M.

    2018-01-01

    We realize a spin-orbit interaction between the collective spin precession and center-of-mass motion of a trapped ultracold atomic gas, mediated by spin- and position-dependent dispersive coupling to a driven optical cavity. The collective spin, precessing near its highest-energy state in an applied magnetic field, can be approximated as a negative-mass harmonic oscillator. When the Larmor precession and mechanical motion are nearly resonant, cavity mediated coupling leads to a negative-mass instability, driving exponential growth of a correlated mode of the hybrid system. We observe this growth imprinted on modulations of the cavity field and estimate the full covariance of the resulting two-mode state by observing its transient decay during subsequent free evolution.

  4. Nonlinear dynamic behaviors of an optically injected vertical-cavity surface-emitting laser

    International Nuclear Information System (INIS)

    Li Xiaofeng; Pan Wei; Luo Bin; Ma Dong; Wang Yong; Li Nuohan

    2006-01-01

    Nonlinear dynamics of a vertical-cavity surface-emitting laser (VCSEL) with external optical injection are studied numerically. We consider a master-slave configuration where the dynamic characteristics of the slave are affected by the optical injection from the master, and we also establish the corresponding Simulink model. The period-doubling route as well as the period-halving route is observed, where the regular, double-periodic, and chaotic pulsings are found. By adjusting the injection strength properly, the laser can be controlled to work at a given state. The effects of frequency detuning on the nonlinear behaviors are also investigated in terms of the bifurcation diagrams of photon density with the frequency detuning. For weak injection case, the nonlinear dynamics shown by the laser are quite different when the value of frequency detuning varies contrarily (positive and negative direction). If the optical injection is strong enough, the slave can be locked by the master even though the frequency detuning is relatively large

  5. Effect of UV irradiation on optical, mechanical and microstructural properties of PVA/NaAlg blends

    Science.gov (United States)

    Sheela, T.; Bhajantri, R. F.; Ravindrachary, V.; Rathod, Sunil G.; Pujari, P. K.; Poojary, Boja; Somashekar, R.

    2014-10-01

    Poly(vinyl alcohol) (PVA)/Sodium alginate (NaAlg) blend films with 60:40 wt% were prepared by solution casting method and subjected to UV irradiation for different intervals of time. The optical, mechanical and morphological properties of the blend films were modified after UV irradiation. The FTIR and FT-Raman results show the chemical interaction between PVA and NaAlg. The UV-vis absorption peak at 278 nm shifts slightly towards longer wavelength and the absorption increases with irradiation time, indicate the increase in crosslinking network. The XRD results show an increase in amorphous nature with increase in UV irradiation time. The DSC/TGA results show a single glass transition temperature (Tg), which confirm that the blends are completely miscible and thermally stable up to 250 °C. The Young's modulus, tensile strength and stiffness of the blend films increase with increase in UV irradiation time. The SEM images confirm that the surface of 48 h UV irradiated PVA:NaAlg blend is more photo-resistant than unirradiated blend.

  6. Quantum-Noise-Limited Sensitivity Enhancement of a Passive Optical Cavity by a Fast-Light Medium

    Science.gov (United States)

    Smith, David D.; Luckay, H. A.; Chang, Hongrok; Myneni, Krishna

    2016-01-01

    We demonstrate for a passive optical cavity containing a dispersive atomic medium, the increase in scale factor near the critical anomalous dispersion is not cancelled by mode broadening or attenuation, resulting in an overall increase in the predicted quantum-noise-limited sensitivity. Enhancements of over two orders of magnitude are measured in the scale factor, which translates to greater than an order-of-magnitude enhancement in the predicted quantum-noise-limited measurement precision, by temperature tuning a low-pressure vapor of non-interacting atoms in a low-finesse cavity close to the critical anomalous dispersion condition. The predicted enhancement in sensitivity is confirmed through Monte-Carlo numerical simulations.

  7. Quantum-Noise-Limited Sensitivity-Enhancement of a Passive Optical Cavity by a Fast-Light Medium

    Science.gov (United States)

    Smith, David D.; Luckay, H. A.; Chang, Hongrok; Myneni, Krishna

    2016-01-01

    We demonstrate for a passive optical cavity containing an intracavity dispersive atomic medium, the increase in scale factor near the critical anomalous dispersion is not cancelled by mode broadening or attenuation, resulting in an overall increase in the predicted quantum-noiselimited sensitivity. Enhancements of over two orders of magnitude are measured in the scale factor, which translates to greater than an order-of-magnitude enhancement in the predicted quantumnoise- limited measurement precision, by temperature tuning a low-pressure vapor of noninteracting atoms in a low-finesse cavity close to the critical anomalous dispersion condition. The predicted enhancement in sensitivity is confirmed through Monte-Carlo numerical simulations.

  8. Vertical‐cavity surface‐emitting laser based digital coherent detection for multigigabit long reach passive optical links

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Jensen, Jesper Bevensee; Zibar, Darko

    2011-01-01

    We report on experimental demonstration of digital coherent detection based on a directly modulated vertical‐cavity surface‐emitting laser with bit rate up to 10 Gbps. This system allows a cooler‐less, free running, and unamplified transmission without optical dispersion compensation up to 105 km...... at 5 Gbps long reach passive optical links. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2462–2464, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26331...

  9. Biophysical mechanisms of modification of skin optical properties in the UV wavelength range with nanoparticles

    Science.gov (United States)

    Popov, A. P.; Priezzhev, A. V.; Lademann, J.; Myllylä, R.

    2009-05-01

    In this paper, by means of the Mie theory and Monte Carlo simulations we investigate modification of optical properties of the superficial layer of human skin (stratum corneum) for 310- and 400-nm ultraviolet (UV) radiation by embedding of 35-200-nm-sized particles of titanium dioxide (TiO2) and silicon (Si). Problem of skin protection against UV light is of major importance due to increased frequency of skin cancer provoked by excessive doses of accepted UV radiation. For 310-nm light, the optimal sizes of the TiO2 and Si particles are found to be 62 and 55 nm, respectively, and for 400-nm radiation, 122 and 70 nm, respectively.

  10. Biophysical mechanisms of modification of skin optical properties in the UV wavelength range with nanoparticles

    International Nuclear Information System (INIS)

    Popov, A. P.; Priezzhev, A. V.; Lademann, J.; Myllylae, R.

    2009-01-01

    In this paper, by means of the Mie theory and Monte Carlo simulations we investigate modification of optical properties of the superficial layer of human skin (stratum corneum) for 310- and 400-nm ultraviolet (UV) radiation by embedding of 35-200-nm-sized particles of titanium dioxide (TiO 2 ) and silicon (Si). Problem of skin protection against UV light is of major importance due to increased frequency of skin cancer provoked by excessive doses of accepted UV radiation. For 310-nm light, the optimal sizes of the TiO 2 and Si particles are found to be 62 and 55 nm, respectively, and for 400-nm radiation, 122 and 70 nm, respectively.

  11. Optical anisotropy of polyimide and polymethacrylate containing photocrosslinkable chalcone group in the side chain under irradiation of a linearly polarized UV light

    CERN Document Server

    Choi, D H

    2002-01-01

    Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy.The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

  12. Cavity-enhanced resonant photoacoustic spectroscopy with optical feedback cw diode lasers: A novel technique for ultratrace gas analysis and high-resolution spectroscopy.

    Science.gov (United States)

    Hippler, Michael; Mohr, Christian; Keen, Katherine A; McNaghten, Edward D

    2010-07-28

    Cavity-enhanced resonant photoacoustic spectroscopy with optical feedback cw diode lasers (OF-CERPAS) is introduced as a novel technique for ultratrace gas analysis and high-resolution spectroscopy. In the scheme, a single-mode cw diode laser (3 mW, 635 nm) is coupled into a high-finesse linear cavity and stabilized to the cavity by optical feedback. Inside the cavity, a build-up of laser power to at least 2.5 W occurs. Absorbing gas phase species inside the cavity are detected with high sensitivity by the photoacoustic effect using a microphone embedded in the cavity. To increase sensitivity further, coupling into the cavity is modulated at a frequency corresponding to a longitudinal resonance of an organ pipe acoustic resonator (f=1.35 kHz and Q approximately 10). The technique has been characterized by measuring very weak water overtone transitions near 635 nm. Normalized noise-equivalent absorption coefficients are determined as alpha approximately 4.4x10(-9) cm(-1) s(1/2) (1 s integration time) and 2.6x10(-11) cm(-1) s(1/2) W (1 s integration time and 1 W laser power). These sensitivities compare favorably with existing state-of-the-art techniques. As an advantage, OF-CERPAS is a "zero-background" method which increases selectivity and sensitivity, and its sensitivity scales with laser power.

  13. Dosimetric UV Exposure Effect on the Optical Properties of Ag2O Doped P2O5-ZnO-CuO Glass

    Directory of Open Access Journals (Sweden)

    K. S. Al Mugren

    2016-01-01

    Full Text Available Silver phosphate glass types within composition 60P2O5-30ZnO-10CuO-100000 ppm Ag2O were prepared by melt-quenching technique. The optical properties of these glass types were studied under UV exposure at different times, 0, 20, 80, 105, and 115 minutes. The optical absorbance spectra were measured in the range of wavelength from 190 to 3200 nm. The absorbance bandwidth decreases with increasing the time of UV exposure. The optical energy gap, Eg, linear refractive index, n, ratio between molar refraction, Rm, and molar volume, Vm, and metallization criterion (M were estimated. The value of Eg decreases from 2.132 to 1.91 eV with increasing the time of UV exposure from 0 to 115 min. Otherwise n value and metallization increase with increase in the time of UV exposure. The results indicated that these glass types are promising for using an ultraviolet radiation dosimeter.

  14. Fundamental limitations of cavity-assisted atom interferometry

    Science.gov (United States)

    Dovale-Álvarez, M.; Brown, D. D.; Jones, A. W.; Mow-Lowry, C. M.; Miao, H.; Freise, A.

    2017-11-01

    Atom interferometers employing optical cavities to enhance the beam splitter pulses promise significant advances in science and technology, notably for future gravitational wave detectors. Long cavities, on the scale of hundreds of meters, have been proposed in experiments aiming to observe gravitational waves with frequencies below 1 Hz, where laser interferometers, such as LIGO, have poor sensitivity. Alternatively, short cavities have also been proposed for enhancing the sensitivity of more portable atom interferometers. We explore the fundamental limitations of two-mirror cavities for atomic beam splitting, and establish upper bounds on the temperature of the atomic ensemble as a function of cavity length and three design parameters: the cavity g factor, the bandwidth, and the optical suppression factor of the first and second order spatial modes. A lower bound to the cavity bandwidth is found which avoids elongation of the interaction time and maximizes power enhancement. An upper limit to cavity length is found for symmetric two-mirror cavities, restricting the practicality of long baseline detectors. For shorter cavities, an upper limit on the beam size was derived from the geometrical stability of the cavity. These findings aim to aid the design of current and future cavity-assisted atom interferometers.

  15. Grated waveguide-based optical cavities as compact sensors for sub-nanometre cantilever deflections, and small refractive-index changes

    NARCIS (Netherlands)

    Kauppinen, L.J.; Hoekstra, Hugo; Dijkstra, Mindert; de Ridder, R.M.; Krijnen, Gijsbertus J.M.; MacCraith, B; McDonagh, C.

    2008-01-01

    The paper reports on theoretical and experimental results of integrated optical (IO) cavities defined by grated waveguides in $Si_3N_4$ and Si, for the accurate detection of cantilever deflection and bulk index changes.

  16. Ionizing Radiation Detectors Based on Ge-Doped Optical Fibers Inserted in Resonant Cavities

    Directory of Open Access Journals (Sweden)

    Saverio Avino

    2015-02-01

    Full Text Available The measurement of ionizing radiation (IR is a crucial issue in different areas of interest, from environmental safety and industrial monitoring to aerospace and medicine. Optical fiber sensors have recently proven good candidates as radiation dosimeters. Here we investigate the effect of IR on germanosilicate optical fibers. A piece of Ge-doped fiber enclosed between two fiber Bragg gratings (FBGs is irradiated with gamma radiation generated by a 6 MV medical linear accelerator. With respect to other FBG-based IR dosimeters, here the sensor is only the bare fiber without any special internal structure. A near infrared laser is frequency locked to the cavity modes for high resolution measurement of radiation induced effects on the fiber optical parameters. In particular, we observe a variation of the fiber thermo-optic response with the radiation dose delivered, as expected from the interaction with Ge defect centers, and demonstrate a detection limit of 360 mGy. This method can have an impact in those contexts where low radiation doses have to be measured both in small volumes or over large areas, such as radiation therapy and radiation protection, while bare optical fibers are cheap and disposable.

  17. Upper limits for absorption by water vapor in the near-UV

    International Nuclear Information System (INIS)

    Wilson, Eoin M.; Wenger, John C.; Venables, Dean S.

    2016-01-01

    There are few experimental measurements of absorption by water vapor in the near-UV. Here we report the results of spectral measurements of water vapor absorption at ambient temperature and pressure from 325 nm to 420 nm, covering most tropospherically relevant short wavelengths. Spectra were recorded using a broadband optical cavity in the chemically controlled environment of an atmospheric simulation chamber. No absorption attributable to the water monomer (or the dimer) was observed at the 0.5 nm resolution of our system. Our results are consistent with calculated spectra and recent DOAS field observations, but contradict a report of significant water absorption in the near-UV. Based on the detection limit of our instrument, we report upper limits for the water absorption cross section of less than 5×10 −26 cm 2 molecule −1 at our instrument resolution. For a typical, indicative slant column density of 4×10 23 cm 2 , we calculate a maximum optical depth of 0.02 arising from absorption of water vapor in the atmosphere at wavelengths between 340 nm and 420 nm, with slightly higher maximum optical depths below 340 nm. The results of this work, together with recent atmospheric observations and computational results, suggest that water vapor absorption across most of the near-UV is small compared to visible and infrared wavelengths. - Highlights: • The absorption cross section of water vapor was studied from 325 to 420 nm. • The upper limit was 5×10 −26 cm 2 molecule −1 above 340 nm at 0.5 nm resolution. • Our result contradicts a recent report of appreciable absorption by water vapor.

  18. Eleven years of monitoring the Seyfert 1 Mrk 335 with Swift: Characterizing the X-ray and UV/optical variability

    Science.gov (United States)

    Gallo, L. C.; Blue, D. M.; Grupe, D.; Komossa, S.; Wilkins, D. R.

    2018-05-01

    The narrow-line Seyfert 1 galaxy (NLS1) Mrk 335 has been continuously monitored with Swift since May 2007 when it fell into a long-lasting, X-ray low-flux interval. Results from the nearly 11 years of monitoring are presented here. Structure functions are used to measure the UV-optical and X-ray power spectra. The X-ray structure function measured between 10 - 100 days is consistent with the flat, low-frequency part of the power spectrum measured previously in Mrk 335. The UV-optical structure functions of Mrk 335 are comparable with those of other Seyfert 1 galaxies and of Mrk 335 itself when it was in a normal bright state. There is no indication that the current X-ray low-flux state is attributed to changes in the accretion disc structure of Mrk 335. The characteristic timescales measured in the structure functions can be attributed to thermal (for the UV) and dynamic (for the optical) timescales in a standard accretion disc. The high-quality UVW2 (˜1800 Å in the source frame) structure function appears to have two breaks and two different slopes between 10 - 160 days. Correlations between the X-ray and other bands are not highly significant when considering the entire 11-year light curves, but more significant behaviour is present when considering segments of the light curves. A correlation between the X-ray and UVW2 in 2014 (Year-8) may be predominately caused by an giant X-ray flare that was interpreted as jet-like emission. In 2008 (Year-2), possible lags between the UVW2 emission and other UV-optical waveband may be consistent with reprocessing of X-ray or UV emission in the accretion disc.

  19. Readout of the UFFO Slewing Mirror Telescope to detect UV/optical photons from Gamma-Ray Bursts

    International Nuclear Information System (INIS)

    Kim, J E; Jung, A; Linder, E V; Na, G W; Lim, H; Nam, J W; Chen, P; Liu, T-C; Brandt, S; Budtz-Jorgensen, C; Castro-Tirado, A J; Choi, H S; Grossan, B; Huang, M A; Jeong, S; Kim, M B; Lee, J; Park, I H; Kim, S-W; Panasyuk, M I

    2013-01-01

    The Slewing Mirror Telescope (SMT) was proposed for rapid response to prompt UV/optical photons from Gamma-Ray Bursts (GRBs). The SMT is a key component of the Ultra-Fast Flash Observatory (UFFO)-pathfinder, which will be launched aboard the Lomonosov spacecraft at the end of 2013. The SMT utilizes a motorized mirror that slews rapidly forward to its target within a second after triggering by an X-ray coded mask camera, which makes unnecessary a reorientation of the entire spacecraft. Subsequent measurement of the UV/optical is accomplished by a 10 cm aperture Ritchey-Chrètien telescope and the focal plane detector of Intensified Charge-Coupled Device (ICCD). The ICCD is sensitive to UV/optical photons of 200–650 nm in wavelength by using a UV-enhanced S20 photocathode and amplifies photoelectrons at a gain of 10 4 –10 6 in double Micro-Channel Plates. These photons are read out by a Kodak KAI-0340 interline CCD sensor and a CCD Signal Processor with 10-bit Analog-to-Digital Converter. Various control clocks for CCD readout are implemented using a Field Programmable Gate Array (FPGA). The SMT readout is in charge of not only data acquisition, storage and transfer, but also control of the slewing mirror, the ICCD high voltage adjustments, power distribution, and system monitoring by interfacing to the UFFO-pathfinder. These functions are realized in the FPGA to minimize power consumption and to enhance processing time. The SMT readout electronics are designed and built to meet the spacecraft's constraints of power consumption, mass, and volume. The entire system is integrated with the SMT optics, as is the UFFO-pathfinder. The system has been tested and satisfies the conditions of launch and those of operation in space: those associated with shock and vibration and those associated with thermal and vacuum, respectively. In this paper, we present the SMT readout electronics: the design, construction, and performance, as well as the results of space environment

  20. Cavity Cooling a Single Charged Levitated Nanosphere

    Science.gov (United States)

    Millen, J.; Fonseca, P. Z. G.; Mavrogordatos, T.; Monteiro, T. S.; Barker, P. F.

    2015-03-01

    Optomechanical cavity cooling of levitated objects offers the possibility for laboratory investigation of the macroscopic quantum behavior of systems that are largely decoupled from their environment. However, experimental progress has been hindered by particle loss mechanisms, which have prevented levitation and cavity cooling in a vacuum. We overcome this problem with a new type of hybrid electro-optical trap formed from a Paul trap within a single-mode optical cavity. We demonstrate a factor of 100 cavity cooling of 400 nm diameter silica spheres trapped in vacuum. This paves the way for ground-state cooling in a smaller, higher finesse cavity, as we show that a novel feature of the hybrid trap is that the optomechanical cooling becomes actively driven by the Paul trap, even for singly charged nanospheres.

  1. Bridging the Gap between RF and Optical Patch Antenna Analysis via the Cavity Model.

    Science.gov (United States)

    Unal, G S; Aksun, M I

    2015-11-02

    Although optical antennas with a variety of shapes and for a variety of applications have been proposed and studied, they are still in their infancy compared to their radio frequency (rf) counterparts. Optical antennas have mainly utilized the geometrical attributes of rf antennas rather than the analysis tools that have been the source of intuition for antenna engineers in rf. This study intends to narrow the gap of experience and intuition in the design of optical patch antennas by introducing an easy-to-understand and easy-to-implement analysis tool in rf, namely, the cavity model, into the optical regime. The importance of this approach is not only its simplicity in understanding and implementation but also its applicability to a broad class of patch antennas and, more importantly, its ability to provide the intuition needed to predict the outcome without going through the trial-and-error simulations with no or little intuitive guidance by the user.

  2. Coupling of single nitrogen-vacancy defect centers in diamond nanocrystals to optical antennas and photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wolters, Janik; Kewes, Guenter; Schell, Andreas W.; Aichele, Thomas; Benson, Oliver [Humboldt-Universitaet zu Berlin, Institut fuer Physik, Berlin (Germany); Nuesse, Nils; Schoengen, Max; Loechel, Bernd [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Hanke, Tobias; Leitenstorfer, Alfred [Department of Physics and Center for Applied Photonics, Universitaet Konstanz, Konstanz (Germany); Bratschitsch, Rudolf [Department of Physics and Center for Applied Photonics, Universitaet Konstanz, Konstanz (Germany); Technische Universitaet Chemnitz, Institut fuer Physik, Chemnitz (Germany)

    2012-05-15

    We demonstrate the ability to modify the emission properties and enhance the interaction strength of single-photon emitters coupled to nanophotonic structures based on metals and dielectrics. Assembly of individual diamond nanocrystals, metal nanoparticles, and photonic crystal cavities to meta-structures is introduced. Experiments concerning controlled coupling of single defect centers in nanodiamonds to optical nanoantennas made of gold bowtie structures are reviewed. By placing one and the same emitter at various locations with high precision, a map of decay rate enhancements was obtained. Furthermore, we demonstrate the formation of a hybrid cavity quantum electrodynamics system in which a single defect center is coupled to a single mode of a gallium phosphite photonic crystal cavity. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Efficient all solid-state UV source for satellite-based lidar applications.

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Darrell Jewell; Smith, Arlee Virgil

    2003-07-01

    A satellite-based UV-DIAL measurement system would allow continuous global monitoring of ozone concentration in the upper atmosphere. However such systems remain difficult to implement because aerosol-scattering return signals for satellite-based lidars are very weak. A suitable system must produce high-energy UV pulses at multiple wavelengths with very high efficiency. For example, a nanosecond system operating at 10 Hz must generate approximately 1 J per pulse at 308-320 nm. An efficient space-qualified wavelength-agile system based on a single UV source that can meet this requirement is probably not available using current laser technology. As an alternative, we're pursuing a multi-source approach employing all-solid-state modules that individually generate 300-320 nm light with pulse energies in the range of 50-200 mJ, with transform-limited bandwidths and good beam quality. Pulses from the individual sources can be incoherently summed to obtain the required single-pulse energy. These sources use sum-frequency mixing of the 532 nm second harmonic of an Nd:YAG pump laser with 731-803 nm light derived from a recently-developed, state-of-the-art, nanosecond optical parametric oscillator. Two source configurations are under development, one using extra-cavity sum-frequency mixing, and the other intra-cavity sum-frequency mixing. In either configuration, we hope to obtain sum-frequency mixing efficiency approaching 60% by carefully matching the spatial and temporal properties of the laser and OPO pulses. This ideal balance of green and near-IR photons requires an injection-seeded Nd:YAG pump-laser with very high beam quality, and an OPO exhibiting unusually high conversion efficiency and exceptional signal beam quality. The OPO employs a singly-resonant high-Fresnel-number image-rotating self-injection-seeded nonplanar-ring cavity that achieves pump depletion > 65% and produces signal beams with M{sup 2} {approx} 3 at pulse energies exceeding 50 mJ. Pump beam

  4. High Energy, Single-Mode, All-Solid-State and Tunable UV Laser Transmitter

    Science.gov (United States)

    Prasad, Narasimha S.; Singh, Upendra N.; Hovis, FLoyd

    2007-01-01

    A high energy, single mode, all solid-state Nd:YAG laser primarily for pumping an UV converter is developed. Greater than 1 J/pulse at 50 HZ PRF and pulse widths around 22 ns have been demonstrated. Higher energy, greater efficiency may be possible. Refinements are known and practical to implement. Technology Demonstration of a highly efficient, high-pulse-energy, single mode UV wavelength generation using flash lamp pumped laser has been achieved. Greater than 90% pump depletion is observed. 190 mJ extra-cavity SFG; IR to UV efficiency > 21% (> 27% for 1 mJ seed). 160 mJ intra-cavity SFG; IR to UV efficiency up to 24% Fluence laser is being refined to match or exceed the above UV converter results. Currently the Nd:YAG pump laser development is a technology demonstration. System can be engineered for compact packaging.

  5. Environment-Assisted Speed-up of the Field Evolution in Cavity Quantum Electrodynamics.

    Science.gov (United States)

    Cimmarusti, A D; Yan, Z; Patterson, B D; Corcos, L P; Orozco, L A; Deffner, S

    2015-06-12

    We measure the quantum speed of the state evolution of the field in a weakly driven optical cavity QED system. To this end, the mode of the electromagnetic field is considered as a quantum system of interest with a preferential coupling to a tunable environment: the atoms. By controlling the environment, i.e., changing the number of atoms coupled to the optical cavity mode, an environment-assisted speed-up is realized: the quantum speed of the state repopulation in the optical cavity increases with the coupling strength between the optical cavity mode and this non-Markovian environment (the number of atoms).

  6. Environment-Assisted Speed-up of the Field Evolution in Cavity Quantum Electrodynamics

    International Nuclear Information System (INIS)

    Cimmarusti, A. D.; Yan, Z.; Patterson, B. D.; Corcos, L. P.; Orozco, L. A.; Deffner, S.

    2015-01-01

    We measure the quantum speed of the state evolution of the field in a weakly-driven optical cavity QED system. To this end, the mode of the electromagnetic field is considered as a quantum system of interest with a preferential coupling to a tunable environment: the atoms. By controlling the environment, i.e., changing the number of atoms coupled to the optical cavity mode, an environment assisted speed-up is realized: the quantum speed of the state re-population in the optical cavity increases with the coupling strength between the optical cavity mode and this non-Markovian environment (the number of atoms)

  7. UV-Vis Ratiometric Resonance Synchronous Spectroscopy for Determination of Nanoparticle and Molecular Optical Cross Sections.

    Science.gov (United States)

    Nettles, Charles B; Zhou, Yadong; Zou, Shengli; Zhang, Dongmao

    2016-03-01

    Demonstrated herein is a UV-vis Ratiometric Resonance Synchronous Spectroscopic (R2S2, pronounced as "R-two-S-two" for simplicity) technique where the R2S2 spectrum is obtained by dividing the resonance synchronous spectrum of a NP-containing solution by the solvent resonance synchronous spectrum. Combined with conventional UV-vis measurements, this R2S2 method enables experimental quantification of the absolute optical cross sections for a wide range of molecular and nanoparticle (NP) materials that range optically from pure photon absorbers or scatterers to simultaneous photon absorbers and scatterers, simultaneous photon absorbers and emitters, and all the way to simultaneous photon absorbers, scatterers, and emitters in the UV-vis wavelength region. Example applications of this R2S2 method were demonstrated for quantifying the Rayleigh scattering cross sections of solvents including water and toluene, absorption and resonance light scattering cross sections for plasmonic gold nanoparticles, and absorption, scattering, and on-resonance fluorescence cross sections for semiconductor quantum dots (Qdots). On-resonance fluorescence quantum yields were quantified for the model molecular fluorophore Eosin Y and fluorescent Qdots CdSe and CdSe/ZnS. The insights and methodology presented in this work should be of broad significance in physical and biological science research that involves photon/matter interactions.

  8. Extending differential optical absorption spectroscopy for limb measurements in the UV

    Directory of Open Access Journals (Sweden)

    J. Puķīte

    2010-05-01

    Full Text Available Methods of UV/VIS absorption spectroscopy to determine the constituents in the Earth's atmosphere from measurements of scattered light are often based on the Beer-Lambert law, like e.g. Differential Optical Absorption Spectroscopy (DOAS. While the Beer-Lambert law is strictly valid for a single light path only, the relation between the optical depth and the concentration of any absorber can be approximated as linear also for scattered light observations at a single wavelength if the absorption is weak. If the light path distribution is approximated not to vary with wavelength, also linearity between the optical depth and the product of the cross-section and the concentration of an absorber can be assumed. These assumptions are widely made for DOAS applications for scattered light observations.

    For medium and strong absorption of scattered light (e.g. along very long light-paths like in limb geometry the relation between the optical depth and the concentration of an absorber is no longer linear. In addition, for broad wavelength intervals the differences in the travelled light-paths at different wavelengths become important, especially in the UV, where the probability for scattering increases strongly with decreasing wavelength.

    However, the DOAS method can be extended to cases with medium to strong absorptions and for broader wavelength intervals by the so called air mass factor modified (or extended DOAS and the weighting function modified DOAS. These approaches take into account the wavelength dependency of the slant column densities (SCDs, but also require a priori knowledge for the air mass factor or the weighting function from radiative transfer modelling.

    We describe an approach that considers the fitting results obtained from DOAS, the SCDs, as a function of wavelength and vertical optical depth and expands this function into a Taylor series of both quantities. The Taylor coefficients are then applied as

  9. [INVITED] Surface plasmon cavities on optical fiber end-facets for biomolecule and ultrasound detection

    Science.gov (United States)

    Yang, Tian; He, Xiaolong; Zhou, Xin; Lei, Zeyu; Wang, Yalin; Yang, Jie; Cai, De; Chen, Sung-Liang; Wang, Xueding

    2018-05-01

    Integrating surface plasmon resonance (SPR) devices upon single-mode fiber (SMF) end facets renders label-free sensing systems that have a simple dip-and-read configuration, a small form factor, high compatibility with fiber-optic techniques, and invasive testing capability. Such devices are not only low cost replacement of current equipments in centralized laboratories, but also highly desirable for opening paths to new applications of label-free optical sensing technologies, such as point-of-care immunological tests and intravascular ultrasound imaging. In this paper, we explain the requirements and challenges for such devices from the perspectives of biomolecule and ultrasound detection applications. In such a context, we review our recent work on SMF end-facet SPR cavities. This include a glue-and-strip fabrication method to transfer a nano-patterned thin gold film to the SMF end-facet with high yield, high quality and high alignment precision, the designs of distributed Bragg reflector (DBR) and distributed feedback (DFB) SPR cavities that couple efficiently with the SMF guided mode and reach quality factors of over 100, and the preliminary results for biomolecule interaction sensing and ultrasound detection. The particular advantages and potential values of these devices have been discussed, in terms of sensitivity, data reliability, reproducibility, bandwidth, etc.

  10. Lasing by driven atoms-cavity system in collective strong coupling regime.

    Science.gov (United States)

    Sawant, Rahul; Rangwala, S A

    2017-09-12

    The interaction of laser cooled atoms with resonant light is determined by the natural linewidth of the excited state. An optical cavity is another optically resonant system where the loss from the cavity determines the resonant optical response of the system. The near resonant combination of an optical Fabry-Pérot cavity with laser cooled and trapped atoms couples two distinct optical resonators via light and has great potential for precision measurements and the creation of versatile quantum optics systems. Here we show how driven magneto-optically trapped atoms in collective strong coupling regime with the cavity leads to lasing at a frequency red detuned from the atomic transition. Lasing is demonstrated experimentally by the observation of a lasing threshold accompanied by polarization and spatial mode purity, and line-narrowing in the outcoupled light. Spontaneous emission into the cavity mode by the driven atoms stimulates lasing action, which is capable of operating as a continuous wave laser in steady state, without a seed laser. The system is modeled theoretically, and qualitative agreement with experimentally observed lasing is seen. Our result opens up a range of new measurement possibilities with this system.

  11. Spectral, structural, optical and dielectrical studies of UV irradiated Rose Bengal thin films prepared by spin coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Zeyada, H.M., E-mail: hzeyada@gmail.com [Department of Physics, Faculty of Science at New Damietta, University of Damietta, 34517 (Egypt); Youssif, M.I.; El-Ghamaz, N.A. [Department of Physics, Faculty of Science at New Damietta, University of Damietta, 34517 (Egypt); Aboderbala, M.E.O. [Department of Physics, Faculty of Science at New Damietta, University of Damietta, 34517 (Egypt); Department of Physics, Faculty of Science, AlJabl Al Gharbi University (Libya)

    2017-02-01

    Optical properties of pristine and UV irradiated Rose Bengal (RB) films have been investigated using transmittance and reflectance methods. The refractive index(n) and extinction coefficient (k) have been calculated from the absolute values of transmission and reflection spectrum. Single oscillator parameters and Drude model of free carrier absorption have been applied for analysis of the refractive index dispersion. Within the frame work of the band-to-band electron transitions theory; the fundamental absorption edge data were analyzed. Our results suggest that thickness of RB films has no effect on the absorption or the refractive indices in the investigated thicknesses range and within the experimental error. Structural transformation of films from amorphous to polycrystalline has been observed upon UV irradiation. Accordingly, the decreases of all of the absorption coefficient, the energy gap and the refractive index of RB films have been detected. Furthermore, the dependence of the optical functions on UV exposure times has been discussed based on the spectral distribution of the dielectric constant.

  12. Cavity-enhanced Raman spectroscopy with optical feedback cw diode lasers for gas phase analysis and spectroscopy.

    Science.gov (United States)

    Salter, Robert; Chu, Johnny; Hippler, Michael

    2012-10-21

    A variant of cavity-enhanced Raman spectroscopy (CERS) is introduced, in which diode laser radiation at 635 nm is coupled into an external linear optical cavity composed of two highly reflective mirrors. Using optical feedback stabilisation, build-up of circulating laser power by 3 orders of magnitude occurs. Strong Raman signals are collected in forward scattering geometry. Gas phase CERS spectra of H(2), air, CH(4) and benzene are recorded to demonstrate the potential for analytical applications and fundamental molecular studies. Noise equivalent limits of detection in the ppm by volume range (1 bar sample) can be achieved with excellent linearity with a 10 mW excitation laser, with sensitivity increasing with laser power and integration time. The apparatus can be operated with battery powered components and can thus be very compact and portable. Possible applications include safety monitoring of hydrogen gas levels, isotope tracer studies (e.g., (14)N/(15)N ratios), observing isotopomers of hydrogen (e.g., radioactive tritium), and simultaneous multi-component gas analysis. CERS has the potential to become a standard method for sensitive gas phase Raman spectroscopy.

  13. Ultraviolet lasing behavior in ZnO optical microcavities

    Directory of Open Access Journals (Sweden)

    Hongxing Dong

    2017-12-01

    Full Text Available Zinc oxide (ZnO optical microcavity modulated UV lasers have been attracting a wide range of research interests. As one of the most important materials in developing high quality microcavity and efficient UV–visible optoelectronic devices due to its wide band gap (3.37 eV and large exciton binding energy (∼60 meV. In this review, we summarized the latest development of ZnO optical cavity based microlasers, mainly including Fabry-Perot mode lasers and whispering gallery mode lasers. The synthesis and optical studies of ZnO optical microcavities with different morphologies were discussed in detail. Finally, we also consider that the research focus in the near future would include new nanotechnology and physical effects, such as nano/micro fabrication, surface plasmon enhancement, and quantum dot coupling, which may result in new and interesting physical phenomena.

  14. Transparent Nanopore Cavity Arrays Enable Highly Parallelized Optical Studies of Single Membrane Proteins on Chip.

    Science.gov (United States)

    Diederichs, Tim; Nguyen, Quoc Hung; Urban, Michael; Tampé, Robert; Tornow, Marc

    2018-06-13

    Membrane proteins involved in transport processes are key targets for pharmaceutical research and industry. Despite continuous improvements and new developments in the field of electrical readouts for the analysis of transport kinetics, a well-suited methodology for high-throughput characterization of single transporters with nonionic substrates and slow turnover rates is still lacking. Here, we report on a novel architecture of silicon chips with embedded nanopore microcavities, based on a silicon-on-insulator technology for high-throughput optical readouts. Arrays containing more than 14 000 inverted-pyramidal cavities of 50 femtoliter volumes and 80 nm circular pore openings were constructed via high-resolution electron-beam lithography in combination with reactive ion etching and anisotropic wet etching. These cavities feature both, an optically transparent bottom and top cap. Atomic force microscopy analysis reveals an overall extremely smooth chip surface, particularly in the vicinity of the nanopores, which exhibits well-defined edges. Our unprecedented transparent chip design provides parallel and independent fluorescent readout of both cavities and buffer reservoir for unbiased single-transporter recordings. Spreading of large unilamellar vesicles with efficiencies up to 96% created nanopore-supported lipid bilayers, which are stable for more than 1 day. A high lipid mobility in the supported membrane was determined by fluorescent recovery after photobleaching. Flux kinetics of α-hemolysin were characterized at single-pore resolution with a rate constant of 0.96 ± 0.06 × 10 -3 s -1 . Here, we deliver an ideal chip platform for pharmaceutical research, which features high parallelism and throughput, synergistically combined with single-transporter resolution.

  15. Storage and retrieval of time-entangled soliton trains in a three-level atom system coupled to an optical cavity

    Science.gov (United States)

    Welakuh, Davis D. M.; Dikandé, Alain M.

    2017-11-01

    The storage and subsequent retrieval of coherent pulse trains in the quantum memory (i.e. cavity-dark state) of three-level Λ atoms, are considered for an optical medium in which adiabatic photon transfer occurs under the condition of quantum impedance matching. The underlying mechanism is based on intracavity Electromagnetically-Induced Transparency, by which properties of a cavity filled with three-level Λ-type atoms are manipulated by an external control field. Under the impedance matching condition, we derive analytic expressions that suggest a complete transfer of an input field into the cavity-dark state by varying the mixing angle in a specific way, and its subsequent retrieval at a desired time. We illustrate the scheme by demonstrating the complete transfer and retrieval of a Gaussian, a single hyperbolic-secant and a periodic train of time-entangled hyperbolic-secant input photon pulses in the atom-cavity system. For the time-entangled hyperbolic-secant input field, a total controllability of the periodic evolution of the dark state population is made possible by changing the Rabi frequency of the classical driving field, thus allowing to alternately store and retrieve high-intensity photons from the optically dense Electromagnetically-Induced transparent medium. Such multiplexed photon states, which are expected to allow sharing quantum information among many users, are currently of very high demand for applications in long-distance and multiplexed quantum communication.

  16. Performance scaling via passive pulse shaping in cavity-enhanced optical parametric chirped-pulse amplification.

    Science.gov (United States)

    Siddiqui, Aleem M; Moses, Jeffrey; Hong, Kyung-Han; Lai, Chien-Jen; Kärtner, Franz X

    2010-06-15

    We show that an enhancement cavity seeded at the full repetition rate of the pump laser can automatically reshape small-signal gain across the interacting pulses in an optical parametric chirped-pulse amplifier for close-to-optimal operation, significantly increasing both the gain bandwidth and the conversion efficiency, in addition to boosting gain for high-repetition-rate amplification. Applied to a degenerate amplifier, the technique can provide an octave-spanning gain bandwidth.

  17. Optical filter finesses enhancement based on nested coupled cavities and active medium

    Science.gov (United States)

    Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

    2016-04-01

    Optical filters with relatively large FSR and narrow linewidth are simultaneously needed for different applications. The ratio between the FSR and the 3-dB linewidth is given by finesse of the filter, which is solely determined by the different energy loss mechanisms limited by the technology advancement. In this work, we present a novel coupled-cavity configuration embedding an optical filter and a gain medium; allowing an overall finesse enhancement and simultaneous FSR and 3-dB linewidth engineering beyond the technological limits of the filter fabrication method. The configuration consists of two resonators. An active ring resonator comprises an optical gain medium and a passive resonator. In one configuration, the optical filter is the passive resonator itself. In a second configuration, the passive resonator is another ring resonator that embeds the optical filter. The presented configurations using a semiconductor optical amplifier are applied one time to a mechanically Fabry-Perot filter in the first presented configuration; and a second time to a fiber ring filter in the second presented configuration. The mechanical filter has an original 3-dB linewidth of 1nm and an FSR that is larger than 100nm while the enhanced linewidth is about 0.3nm. The fiber ring filter length is 4 m and directional coupler ratios of 90/10corresponding to a 3-dBlinewidth of about 4MHz and an FSR of 47 MHz. The enhanced 3- dBlinewidth of the overall filter configuration is 200kHz, demonstrating finesse enhancement up to20 times the original finesse of the filter.

  18. Pulsed UV laser-induced modifications in optical and structural characteristics of alpha-irradiated PM-355 SSNTD.

    Science.gov (United States)

    Alghamdi, S S; Farooq, W A; Baig, M R; Algarawi, M S; Alrashidi, Talal Mohammed; Ali, Syed Mansoor; Alfaramawi, K

    2017-10-01

    Pre- and postalpha-exposed PM-355 detectors were irradiated using UV laser with different number of pulses (100, 150, 200, 300, and 400). UV laser beam energy of 20mJ per pulse with a pulse width of 9ns was incident on an area of 19.6mm 2 of the samples. XRD spectra indicated that for both reference and UV-irradiated samples, the structure is amorphous, but the crystallite size increases upon UV irradiation. The same results were obtained from SEM analysis. Optical properties of PM-355 polymeric solid-state nuclear track detectors were also investigated. Absorbance measurements for all PM-355 samples in the range of 200-400nm showed that the absorption edge had a blue shift up to a certain value, and then, it had an oscillating behavior. Photoluminescence spectra of PM-355 at 250nm revealed a decrease in the broadband peak intensity as a function of the number of UV pulses, while the wavelengths corresponding to the peaks had random shifts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Transition-edge sensor arrays for UV-optical-IR astrophysics

    International Nuclear Information System (INIS)

    Burney, J.; Bay, T.J.; Barral, J.; Brink, P.L.; Cabrera, B.; Castle, J.P.; Miller, A.J.; Nam, S.; Rosenberg, D.; Romani, R.W.; Tomada, A.

    2006-01-01

    Our research group has developed and characterized transition-edge sensor (TES) arrays for near IR-optical-near UV astrophysical observations. These detectors have a time-stamp accuracy of 0.3μs and an energy resolution of 0.16eV for 2.33eV photons at very high rates (30kHz). We have installed a 6x6 array of these TESs in an adiabatic demagnetization refrigerator equipped with windows for direct imaging. We discuss new instrumentation progress and current data in all aspects related to successful operation of this camera system, including: detector and array performance, position dependence and cross-talk, low-temperature and readout electronics, quantum and system efficiency, IR filtering, and focus and imaging

  20. Cavity Optomechanics at Millikelvin Temperatures

    Science.gov (United States)

    Meenehan, Sean Michael

    The field of cavity optomechanics, which concerns the coupling of a mechanical object's motion to the electromagnetic field of a high finesse cavity, allows for exquisitely sensitive measurements of mechanical motion, from large-scale gravitational wave detection to microscale accelerometers. Moreover, it provides a potential means to control and engineer the state of a macroscopic mechanical object at the quantum level, provided one can realize sufficiently strong interaction strengths relative to the ambient thermal noise. Recent experiments utilizing the optomechanical interaction to cool mechanical resonators to their motional quantum ground state allow for a variety of quantum engineering applications, including preparation of non-classical mechanical states and coherent optical to microwave conversion. Optomechanical crystals (OMCs), in which bandgaps for both optical and mechanical waves can be introduced through patterning of a material, provide one particularly attractive means for realizing strong interactions between high-frequency mechanical resonators and near-infrared light. Beyond the usual paradigm of cavity optomechanics involving isolated single mechanical elements, OMCs can also be fashioned into planar circuits for photons and phonons, and arrays of optomechanical elements can be interconnected via optical and acoustic waveguides. Such coupled OMC arrays have been proposed as a way to realize quantum optomechanical memories, nanomechanical circuits for continuous variable quantum information processing and phononic quantum networks, and as a platform for engineering and studying quantum many-body physics of optomechanical meta-materials. However, while ground state occupancies (that is, average phonon occupancies less than one) have been achieved in OMC cavities utilizing laser cooling techniques, parasitic absorption and the concomitant degradation of the mechanical quality factor fundamentally limit this approach. On the other hand, the high

  1. Properties of optical breakdown in BK7 glass induced by an extended-cavity femtosecond laser oscillator.

    Science.gov (United States)

    Do, Binh T; Phillips, Mark C; Miller, Paul A; Kimmel, Mark W; Britsch, Justin; Cho, Seong-Ho

    2009-02-16

    Using an extended-cavity femtosecond oscillator, we investigated optical breakdown in BK7 glass caused by the accumulated action of many laser pulses. By using a pump-probe experiment and collecting the transmitted pump along with the reflected pump and the broadband light generated by the optical breakdown, we measured the build-up time to optical breakdown as a function of the pulse energy, and we also observed the instability of the plasma due to the effect of defocusing and shielding created by the electron gas. The spectrum of the broadband light emitted by the optical breakdown and the origin of the material modification in BK7 glass was studied. We developed a simple model of electromagnetic wave propagation in plasma that is consistent with the observed behavior of the reflection, absorption, and transmission of the laser light.

  2. Athermalization of resonant optical devices via thermo-mechanical feedback

    Science.gov (United States)

    Rakich, Peter; Nielson, Gregory N.; Lentine, Anthony L.

    2016-01-19

    A passively athermal photonic system including a photonic circuit having a substrate and an optical cavity defined on the substrate, and passive temperature-responsive provisions for inducing strain in the optical cavity of the photonic circuit to compensate for a thermo-optic effect resulting from a temperature change in the optical cavity of the photonic circuit. Also disclosed is a method of passively compensating for a temperature dependent thermo-optic effect resulting on an optical cavity of a photonic circuit including the step of passively inducing strain in the optical cavity as a function of a temperature change of the optical cavity thereby producing an elasto-optic effect in the optical cavity to compensate for the thermo-optic effect resulting on an optical cavity due to the temperature change.

  3. An Optomechanical Elevator: Transport of a Bloch Oscillating Bose–Einstein Condensate up and down an Optical Lattice by Cavity Sideband Amplification and Cooling

    Directory of Open Access Journals (Sweden)

    B. Prasanna Venkatesh

    2015-12-01

    Full Text Available In this paper we give a new description, in terms of optomechanics, of previous work on the problem of an atomic Bose–Einstein condensate interacting with the optical lattice inside a laser-pumped optical cavity and subject to a bias force, such as gravity. An atomic wave packet in a tilted lattice undergoes Bloch oscillations; in a high-finesse optical cavity the backaction of the atoms on the light leads to a time-dependent modulation of the intracavity lattice depth at the Bloch frequency which can in turn transport the atoms up or down the lattice. In the optomechanical picture, the transport dynamics can be interpreted as a manifestation of dynamical backaction-induced sideband damping/amplification of the Bloch oscillator. Depending on the sign of the pump-cavity detuning, atoms are transported either with or against the bias force accompanied by an up- or down-conversion of the frequency of the pump laser light. We also evaluate the prospects for using the optomechanical Bloch oscillator to make continuous measurements of forces by reading out the Bloch frequency. In this context, we establish the significant result that the optical spring effect is absent and the Bloch frequency is not modified by the backaction.

  4. Improved Algorithms for Accurate Retrieval of UV - Visible Diffuse Attenuation Coefficients in Optically Complex, Inshore Waters

    Science.gov (United States)

    Cao, Fang; Fichot, Cedric G.; Hooker, Stanford B.; Miller, William L.

    2014-01-01

    Photochemical processes driven by high-energy ultraviolet radiation (UVR) in inshore, estuarine, and coastal waters play an important role in global bio geochemical cycles and biological systems. A key to modeling photochemical processes in these optically complex waters is an accurate description of the vertical distribution of UVR in the water column which can be obtained using the diffuse attenuation coefficients of down welling irradiance (Kd()). The Sea UV Sea UVc algorithms (Fichot et al., 2008) can accurately retrieve Kd ( 320, 340, 380,412, 443 and 490 nm) in oceanic and coastal waters using multispectral remote sensing reflectances (Rrs(), Sea WiFS bands). However, SeaUVSeaUVc algorithms are currently not optimized for use in optically complex, inshore waters, where they tend to severely underestimate Kd(). Here, a new training data set of optical properties collected in optically complex, inshore waters was used to re-parameterize the published SeaUVSeaUVc algorithms, resulting in improved Kd() retrievals for turbid, estuarine waters. Although the updated SeaUVSeaUVc algorithms perform best in optically complex waters, the published SeaUVSeaUVc models still perform well in most coastal and oceanic waters. Therefore, we propose a composite set of SeaUVSeaUVc algorithms, optimized for Kd() retrieval in almost all marine systems, ranging from oceanic to inshore waters. The composite algorithm set can retrieve Kd from ocean color with good accuracy across this wide range of water types (e.g., within 13 mean relative error for Kd(340)). A validation step using three independent, in situ data sets indicates that the composite SeaUVSeaUVc can generate accurate Kd values from 320 490 nm using satellite imagery on a global scale. Taking advantage of the inherent benefits of our statistical methods, we pooled the validation data with the training set, obtaining an optimized composite model for estimating Kd() in UV wavelengths for almost all marine waters. This

  5. Quasi-optical mode converter for a coaxial cavity gyrotron

    International Nuclear Information System (INIS)

    Jin, J.

    2007-03-01

    This work concentrates on the synthesis of the quasioptical mode converter for the 170 GHz, TE 34,19 -mode, 2MW, CW coaxial-cavity gyrotron at Forschungszentrum Karlsruhe (FZK). The improvement of the general method for the design of so-call dimpled-wall launcher to provide a good Gaussian mode content is described. This method is verified through the design of a launcher operating in the TE 22,6 mode at 118 GHz. A phase rule is proposed as a quality criterion for monitoring the optimization and the choices of parameters of the quasi-optical mode converter. High-order harmonics introduced to the launcher wall deformations are proposed for this gyrotron. The launcher is numerically optimized, the fields on the cut edges are suppressed. The fields in the launcher are well approximated by the waveguide modes, the radiated fields are calculated using the scalar diffraction integral. The procedure for the numerical optimization of the mirror system is improved, the tolerance conditions of the phase correcting mirrors are investigated. A conversion efficiency of 95.8% to the circular fundamental Gaussian distribution with 20mm beam waist and power transmission of 90% are achieved in the window plane using the optimized quasi-optical mode converter. The methods to ameliorate the initial conditions of the phase correcting mirrors are explored. (orig.)

  6. The Intrinsically X-Ray-weak Quasar PHL 1811. II. Optical and UV Spectra and Analysis

    Science.gov (United States)

    Leighly, Karen M.; Halpern, Jules P.; Jenkins, Edward B.; Casebeer, Darrin

    2007-11-01

    This is the second of two papers reporting observations and analysis of the unusually bright (mb=14.4), luminous (MB=-25.5), nearby (z=0.192) narrow-line quasar PHL 1811. The first paper reported that PHL 1811 is intrinsically X-ray-weak and presented a spectral energy distribution (SED). Here we present HST STIS optical and UV spectra, and ground-based optical spectra. The optical and UV line emission is very unusual. There is no evidence for forbidden or semiforbidden lines. The near-UV spectrum is dominated by very strong Fe II and Fe III, and unusual low-ionization lines such as Na I D and Ca II H and K are observed. High-ionization lines are very weak; C IV has an equivalent width of 6.6 Å, a factor of ~5 smaller than measured from quasar composite spectra. An unusual feature near 1200 Å can be deblended in terms of Lyα, N V, Si II, and C III* using the blueshifted C IV profile as a template. Photoionization modeling shows that the unusual line emission can be explained qualitatively by the unusually soft SED. Principally, a low gas temperature results in inefficient emission of collisionally excited lines, including the semiforbidden lines generally used as density diagnostics. The emission resembles that of high-density gas; in both cases this is a consequence of inefficient cooling. PHL 1811 is very unusual, but we note that quasar surveys may be biased against finding similar objects. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with proposal 9181. Based on observations obtained at Kitt Peak National Observatory, a division of the National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.

  7. Dispersion of coupled mode-gap cavities

    NARCIS (Netherlands)

    Lian, Jin; Sokolov, Sergei; Yuce, E.; Combrie, S.; de Rossi, A.; Mosk, Allard

    2015-01-01

    The dispersion of a coupled resonator optical waveguide made of photonic crystal mode-gap cavities is pronouncedly asymmetric. This asymmetry cannot be explained by the standard tight binding model. We show that the fundamental cause of the asymmetric dispersion is the inherent dispersive cavity

  8. Short-cavity squeezing in barium

    Science.gov (United States)

    Hope, D. M.; Bachor, H-A.; Manson, P. J.; Mcclelland, D. E.

    1992-01-01

    Broadband phase sensitive noise and squeezing were experimentally observed in a system of barium atoms interacting with a single mode of a short optical cavity. Squeezing of 13 +/- 3 percent was observed. A maximum possible squeezing of 45 +/- 8 percent could be inferred for out experimental conditions, after correction for measured loss factors. Noise reductions below the quantum limit were found over a range of detection frequencies 60-170 MHz and were best for high cavity transmission and large optical depths. The amount of squeezing observed is consistent with theoretical predictions from a full quantum statistical model of the system.

  9. Droplet based cavities and lasers

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Kristensen, Anders; Mortensen, Asger

    2009-01-01

    The self-organized and molecularly smooth surface on liquid microdroplets makes them attractive as optical cavities with very high quality factors. This chapter describes the basic theory of optical modes in spherical droplets. The mechanical properties including vibrational excitation are also d...

  10. Tunneling effect in cavity-resonator-coupled arrays

    International Nuclear Information System (INIS)

    Ma Hua; Xu Zhuo; Qu Shao-Bo; Zhang Jie-Qiu; Wang Jia-Fu; Liang Chang-Hong

    2013-01-01

    The quantum tunneling effect (QTE) in a cavity-resonator-coupled (CRC) array was analytically and numerically investigated. The underlying mechanism was interpreted by treating electromagnetic waves as photons, and then was generalized to acoustic waves and matter waves. It is indicated that for the three kinds of waves, the QTE can be excited by cavity resonance in a CRC array, resulting in sub-wavelength transparency through the narrow splits between cavities. This opens up opportunities for designing new types of crystals based on CRC arrays, which may find potential applications such as quantum devices, micro-optic transmission, and acoustic manipulation. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  11. Intra-cavity vortex beam generation

    CSIR Research Space (South Africa)

    Naidoo, Darryl

    2011-08-01

    Full Text Available at exploring the methods of generating optical vortex beams. We will discuss a typical extra-cavity approach that harnesses digital holography through the use of a SLM. We consider vortex beam generation as the fundamental mode of a monolithic microchip laser...-cavity phase diffractive elements can result in the desired mode as the fundamental mode of the cavity with pure modal quality. This approach, although very attractive is insufficient for the generation of these modes in monolithic microchip lasers. A...

  12. Acousto-Optic Q-Switched Fiber Laser-Based Intra-Cavity Photoacoustic Spectroscopy for Trace Gas Detection.

    Science.gov (United States)

    Zhang, Qinduan; Chang, Jun; Wang, Qiang; Wang, Zongliang; Wang, Fupeng; Qin, Zengguang

    2017-12-25

    We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency f ₀ = 5.3 kHz) inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C₂H₂) to select the laser wavelength. The system achieved a linear response (R² = 0.9941) in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times.

  13. The potential for optical beam shaping of UV laser sources for mass scale quarantine disinfection applications

    Science.gov (United States)

    Lizotte, Todd

    2010-08-01

    disinfection systems using high intensity UV laser sources instead of UV bulb techniques by using laser beam shaping optics in conjunction with traditional optical laser beam delivery techniques.

  14. A novel nano-sensor based on optomechanical crystal cavity

    Science.gov (United States)

    Zhang, Yeping; Ai, Jie; Ma, Jingfang

    2017-10-01

    Optical devices based on new sensing principle are widely used in biochemical and medical area. Nowadays, mass sensing based on monitoring the frequency shifts induced by added mass in oscillators is a well-known and widely used technique. It is interesting to note that for nanoscience and nanotechnology applications there is a strong demand for very sensitive mass sensors, being the target a sensor for single molecule detection. The desired mass resolution for very few or even single molecule detection, has to be below the femtogram range. Considering the strong interaction between high co-localized optical mode and mechanical mode in optomechanical crystal (OMC) cavities, we investigate OMC splitnanobeam cavities in silicon operating near at the 1550nm to achieve high optomechanical coupling rate and ultra-small motion mass. Theoretical investigations of the optical and mechanical characteristic for the proposed cavity are carried out. By adjusting the structural parameters, the cavity's effective motion mass below 10fg and mechanical frequency exceed 10GHz. The transmission spectrum of the cavity is sensitive to the sample which located on the center of the cavity. We conducted the fabrication and the characterization of this cavity sensor on the silicon-on-insulator (SOI) chip. By using vertical coupling between the tapered fiber and the SOI chip, we measured the transmission spectrum of the cavity, and verify this cavity is promising for ultimate precision mass sensing and detection.

  15. Sequential capillary electrophoresis analysis using optically gated sample injection and UV/vis detection.

    Science.gov (United States)

    Liu, Xiaoxia; Tian, Miaomiao; Camara, Mohamed Amara; Guo, Liping; Yang, Li

    2015-10-01

    We present sequential CE analysis of amino acids and L-asparaginase-catalyzed enzyme reaction, by combing the on-line derivatization, optically gated (OG) injection and commercial-available UV-Vis detection. Various experimental conditions for sequential OG-UV/vis CE analysis were investigated and optimized by analyzing a standard mixture of amino acids. High reproducibility of the sequential CE analysis was demonstrated with RSD values (n = 20) of 2.23, 2.57, and 0.70% for peak heights, peak areas, and migration times, respectively, and the LOD of 5.0 μM (for asparagine) and 2.0 μM (for aspartic acid) were obtained. With the application of the OG-UV/vis CE analysis, sequential online CE enzyme assay of L-asparaginase-catalyzed enzyme reaction was carried out by automatically and continuously monitoring the substrate consumption and the product formation every 12 s from the beginning to the end of the reaction. The Michaelis constants for the reaction were obtained and were found to be in good agreement with the results of traditional off-line enzyme assays. The study demonstrated the feasibility and reliability of integrating the OG injection with UV/vis detection for sequential online CE analysis, which could be of potential value for online monitoring various chemical reaction and bioprocesses. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Characterization technique for long optical fiber cavities based on beating spectrum of multi-longitudinal mode fiber laser and beating spectrum in the RF domain

    Science.gov (United States)

    Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

    2016-03-01

    The characterization of long fiber cavities is essential for many systems to predict the system practical performance. The conventional techniques for optical cavity characterization are not suitable for long fiber cavities due to the cavities' small free spectral ranges and due to the length variations caused by the environmental effects. In this work, we present a novel technique to characterize long fiber cavities using multi-longitudinal mode fiber laser source and RF spectrum analyzer. The fiber laser source is formed in a ring configuration, where the fiber laser cavity length is chosen to be 15 km to ensure that the free spectral range is much smaller than the free spectral range of the characterized passive fiber cavities. The method has been applied experimentally to characterize ring cavities with lengths of 6.2 m and 2.4 km. The results are compared to theoretical predictions with very good agreement.

  17. Wideband perfect coherent absorber based on white-light cavity

    Science.gov (United States)

    Kotlicki, Omer; Scheuer, Jacob

    2015-03-01

    Coherent Perfect Absorbers (CPAs) are optical cavities which can be described as time-reversed lasers where light waves that enter the cavity, coherently interfere and react with the intra-cavity losses to yield perfect absorption. In contrast to lasers, which benefit from high coherency and narrow spectral linewidths, for absorbers these properties are often undesirable as absorption at a single frequency is highly susceptible to spectral noise and inappropriate for most practical applications. Recently, a new class of cavities, characterized by a spectrally wide resonance has been proposed. Such resonators, often referred to as White Light Cavities (WLCs), include an intra-cavity superluminal phase element, designed to provide a phase response with a slope that is opposite in sign and equal in magnitude to that of light propagation through the empty cavity. Consequently, the resonance phase condition in WLCs is satisfied over a band of frequencies providing a spectrally wide resonance. WLCs have drawn much attention due to their attractiveness for various applications such as ultra-sensitive sensors and optical buffering components. Nevertheless, WLCs exhibit inherent losses that are often undesirable. Here we introduce a simple wideband CPA device that is based on the WLC concept along with a complete analytical analysis. We present analytical and FDTD simulations of a practical, highly compact (12µm), Silicon based WLC-CPA that exhibits a flat and wide absorption profile (40nm) and demonstrate its usefulness as an optical pulse terminator (>35db isolation) and an all optical modulator that span the entire C-Band and exhibit high immunity to spectral noise.

  18. Low-loss tunable 1D ITO-slot photonic crystal nanobeam cavity

    Science.gov (United States)

    Amin, Rubab; Tahersima, Mohammad H.; Ma, Zhizhen; Suer, Can; Liu, Ke; Dalir, Hamed; Sorger, Volker J.

    2018-05-01

    Tunable optical material properties enable novel applications in both versatile metamaterials and photonic components including optical sources and modulators. Transparent conductive oxides (TCOs) are able to highly tune their optical properties with applied bias via altering their free carrier concentration and hence plasma dispersion. The TCO material indium tin oxide (ITO) exhibits unity-strong index change and epsilon-near-zero behavior. However, with such tuning the corresponding high optical losses, originating from the fundamental Kramers–Kronig relations, result in low cavity finesse. However, achieving efficient tuning in ITO-cavities without using light–matter interaction enhancement techniques such as polaritonic modes, which are inherently lossy, is a challenge. Here we discuss a novel one-dimensional photonic crystal nanobeam cavity to deliver a cavity system offering a wide range of resonance tuning range, while preserving physical compact footprints. We show that a vertical silicon-slot waveguide incorporating an actively gated-ITO layer delivers ∼3.4 nm of tuning. By deploying distributed feedback, we are able to keep the Q-factor moderately high with tuning. Combining this with the sub-diffraction limited mode volume (0.1 (λ/2n)3) from the photonic (non-plasmonic) slot waveguide, facilitates a high Purcell factor exceeding 1000. This strong light–matter-interaction shows that reducing the mode volume of a cavity outweighs reducing the losses in diffraction limited modal cavities such as those from bulk Si3N4. These tunable cavities enable future modulators and optical sources such as tunable lasers.

  19. Nonlinear dynamics and cavity cooling of levitated nanoparticles

    Science.gov (United States)

    Fonseca, P. Z. G.; Aranas, E. B.; Millen, J.; Monteiro, T. S.; Barker, P. F.

    2016-09-01

    We investigate a dynamic nonlinear optomechanical system, comprising a nanosphere levitated in a hybrid electro-optical trap. An optical cavity offers readout of both linear-in-position and quadratic-in-position (nonlinear) light-matter coupling, whilst simultaneously cooling the nanosphere, for indefinite periods of time and in high vacuum. Through the rich sideband structure displayed by the cavity output we can observe cooling of the linear and non-linear particle's motion. Here we present an experimental setup which allows full control over the cavity resonant frequencies, and shows cooling of the particle's motion as a function of the detuning. This work paves the way to strong-coupled quantum dynamics between a cavity and a mesoscopic object largely decoupled from its environment.

  20. UV written compact broadband optical couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques.......In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques....

  1. Design and fabrication of ultrathin silicon-nitride membranes for use in UV-visible airgap-based MEMS optical filters

    International Nuclear Information System (INIS)

    Ghaderi, Mohammadamir; Wolffenbuttel, Reinoud F.

    2016-01-01

    MEMS-based airgap optical filters are composed of quarter-wave thick high-index dielectric membranes that are separated by airgaps. The main challenge in the fabrication of these filters is the intertwined optical and mechanical requirements. The thickness of the layers decreases with design wavelength, which makes the optical performance in the UV more susceptible to fabrication tolerances, such as thickness and composition of the deposited layers, while the ability to sustain a certain level of residual stress by the structural strength becomes more critical. Silicon-nitride has a comparatively high Young's modulus and good optical properties, which makes it a suitable candidate as the membrane material. However, both the mechanical and optical properties in a silicon-nitride film strongly depend on the specifics of the deposition process. A design trade-off is required between the mechanical strength and the index of refraction, by tuning the silicon content in the silicon-nitride film. However, also the benefit of a high index of refraction in a silicon-rich film should be weighed against the increased UV optical absorption. This work presents the design, fabrication, and preliminary characterization of one and three quarter-wave thick silicon-nitride membranes with a one-quarter airgap and designed to give a spectral reflectance at 400 nm. The PECVD silicon-nitride layers were initially characterized, and the data was used for the optical and mechanical design of the airgap filters. A CMOS compatible process based on polysilicon sacrificial layers was used for the fabrication of the membranes. Optical characterization results are presented. (paper)

  2. Penetration of UV-A, UV-B and blue light through the leaf trichome layers of two xeromorphic plants, olive and oak, measured by optical fibre microprobes

    International Nuclear Information System (INIS)

    Karabourniotis, G.; Bornman, J.F.

    1999-01-01

    Quartz fibre-optic microprobes were used to monitor the light microenvironment beneath trichome layers of the xeromorphic leaves of two Mediterranean evergreen sclerophylls, Olea europaea and Quercus ilex. Young developing leaves of both plants were densely pubescent on both surfaces of the lamina, whereas the mature leaves were pubescent only on the abaxial side. Trichome layers of young as well as of mature leaves of both plants attenuated almost all incident ultraviolet (UV)-B (310 nm) and UV-A (360 nm) radiation and a considerable portion of blue light (430 nm). Abaxial trichome layers of young leaves were more effective in screening out the incident radiation compared to the adaxial ones of the same leaves and also compared to the abaxial layer of the mature leaves. The abaxial epidermis of dehaired mature leaves of O. europaea was ineffective in absorbing most of the incident UV-B and UV-A radiation. UV and visible spectra beneath trichome layers of O. europaea in mature leaves confirmed that the light microenvironment on the epidermis was deprived in the UV-B, UV-A and partly in the blue spectral regions. It is proposed that the occurrence of a dense trichome layer, especially in young leaves, may play a protective role against not only UV-B radiation damage, but also against high visible irradiance. This function is performed irrespective of the differing anatomy of individual hairs of both plants. The protection provided by the trichomes could afford advantages under stress conditions, especially during leaf development. (author)

  3. Sensitive detection of individual neutral atoms in a strong coupling cavity QED system

    International Nuclear Information System (INIS)

    Zhang Pengfei; Zhang Yuchi; Li Gang; Du Jinjin; Zhang Yanfeng; Guo Yanqiang; Wang Junmin; Zhang Tiancai; Li Weidong

    2011-01-01

    We experimentally demonstrate real-time detection of individual cesium atoms by using a high-finesse optical micro-cavity in a strong coupling regime. A cloud of cesium atoms is trapped in a magneto-optical trap positioned at 5 mm above the micro-cavity center. The atoms fall down freely in gravitation after shutting off the magneto-optical trap and pass through the cavity. The cavity transmission is strongly affected by the atoms in the cavity, which enables the micro-cavity to sense the atoms individually. We detect the single atom transits either in the resonance or various detunings. The single atom vacuum-Rabi splitting is directly measured to be Ω = 2π × 23.9 MHz. The average duration of atom-cavity coupling of about 110 μs is obtained according to the probability distribution of the atom transits. (authors)

  4. Aerosol effects on UV radiation

    International Nuclear Information System (INIS)

    Koepke, P.; Reuder, J.; Schwander, H.

    2000-01-01

    The reduction of erythemally weighted UV-irradiance (given as UV index, UVI) due to aerosols is analyzed by variation of the tropospheric particles in a wide, but realistic range. Varied are amount and composition of the particles and relative humidity and thickness of the mixing layer. The reduction of UVI increases with aerosol optical depth and the UV change is around 10% for a change aerosol optical depth from 0.25 to 0.1 and 0.4 respectively. Since both aerosol absorption and scattering are of relevance, the aerosol effect depends besides total aerosol amount on relative amount of soot and on relative humidity

  5. Momentum diffusion for coupled atom-cavity oscillators

    International Nuclear Information System (INIS)

    Murr, K.; Maunz, P.; Pinkse, P. W. H.; Puppe, T.; Schuster, I.; Rempe, G.; Vitali, D.

    2006-01-01

    It is shown that the momentum diffusion of free-space laser cooling has a natural correspondence in optical cavities when the internal state of the atom is treated as a harmonic oscillator. We derive a general expression for the momentum diffusion, which is valid for most configurations of interest: The atom or the cavity or both can be probed by lasers, with or without the presence of traps inducing local atomic frequency shifts. It is shown that, albeit the (possibly strong) coupling between atom and cavity, it is sufficient for deriving the momentum diffusion to consider that the atom couples to a mean cavity field, which gives a first contribution, and that the cavity mode couples to a mean atomic dipole, giving a second contribution. Both contributions have an intuitive form and present a clear symmetry. The total diffusion is the sum of these two contributions plus the diffusion originating from the fluctuations of the forces due to the coupling to the vacuum modes other than the cavity mode (the so-called spontaneous emission term). Examples are given that help to evaluate the heating rates induced by an optical cavity for experiments operating at low atomic saturation. We also point out intriguing situations where the atom is heated although it cannot scatter light

  6. Quantum simulation of 2D topological physics in a 1D array of optical cavities.

    Science.gov (United States)

    Luo, Xi-Wang; Zhou, Xingxiang; Li, Chuan-Feng; Xu, Jin-Shi; Guo, Guang-Can; Zhou, Zheng-Wei

    2015-07-06

    Orbital angular momentum of light is a fundamental optical degree of freedom characterized by unlimited number of available angular momentum states. Although this unique property has proved invaluable in diverse recent studies ranging from optical communication to quantum information, it has not been considered useful or even relevant for simulating nontrivial physics problems such as topological phenomena. Contrary to this misconception, we demonstrate the incredible value of orbital angular momentum of light for quantum simulation by showing theoretically how it allows to study a variety of important 2D topological physics in a 1D array of optical cavities. This application for orbital angular momentum of light not only reduces required physical resources but also increases feasible scale of simulation, and thus makes it possible to investigate important topics such as edge-state transport and topological phase transition in a small simulator ready for immediate experimental exploration.

  7. Acousto-Optic Q-Switched Fiber Laser-Based Intra-Cavity Photoacoustic Spectroscopy for Trace Gas Detection

    Directory of Open Access Journals (Sweden)

    Qinduan Zhang

    2017-12-01

    Full Text Available We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency f0 = 5.3 kHz inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C2H2 to select the laser wavelength. The system achieved a linear response (R2 = 0.9941 in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times.

  8. UV-induced carbon monoxide emission from living vegetation

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2013-01-01

    The global burden of carbon monoxide (CO) is rather uncertain. In this paper we address the potential for UV-induced CO emission by living terrestrial vegetation surfaces. Real-time measurements of CO concentrations were made with a cavity enhanced laser spectrometer connected in closed loop...... to either an ecosystem chamber or a plant-leaf scale chamber. Leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation as well as the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature......, indicating an abiotic process. The emission of CO in response to the UV-component of natural solar radiation was also evident at the ecosystem scale....

  9. The effect of nonadiabaticity on the efficiency of quantum memory based on an optical cavity

    Science.gov (United States)

    Veselkova, N. G.; Sokolov, I. V.

    2017-07-01

    Quantum efficiency is an important characteristic of quantum memory devices that are aimed at recording the quantum state of light signals and its storing and reading. In the case of memory based on an ensemble of cold atoms placed in an optical cavity, the efficiency is restricted, in particular, by relaxation processes in the system of active atomic levels. We show how the effect of the relaxation on the quantum efficiency can be determined in a regime of the memory usage in which the evolution of signals in time is not arbitrarily slow on the scale of the field lifetime in the cavity and when the frequently used approximation of the adiabatic elimination of the quantized cavity mode field cannot be applied. Taking into account the effect of the nonadiabaticity on the memory quality is of interest in view of the fact that, in order to increase the field-medium coupling parameter, a higher cavity quality factor is required, whereas storing and processing of sequences of many signals in the memory implies that their duration is reduced. We consider the applicability of the well-known efficiency estimates via the system cooperativity parameter and estimate a more general form. In connection with the theoretical description of the memory of the given type, we also discuss qualitative differences in the behavior of a random source introduced into the Heisenberg-Langevin equations for atomic variables in the cases of a large and a small number of atoms.

  10. Optical micro-cavities on silicon

    Science.gov (United States)

    Dai, Daoxin; Liu, Erhu; Tan, Ying

    2018-01-01

    Silicon-based optical microcavities are very popular for many applications because of the ultra-compact footprint, easy scalability, and functional versatility. In this paper we give a discussion about the challenges of the optical microcavities on silicon and also give a review of our recent work, including the following parts. First, a near-"perfect" high-order MRR optical filter with a box-like filtering response is realized by introducing bent directional couplers to have sufficient coupling between the access waveguide and the microrings. Second, an efficient thermally-tunable MRR-based optical filter with graphene transparent nano-heater is realized by introducing transparent graphene nanoheaters. Thirdly, a polarization-selective microring-based optical filter is realized to work with resonances for only one of TE and TM polarizations for the first time. Finally, a on-chip reconfigurable optical add-drop multiplexer for hybrid mode- /wavelength-division-multiplexing systems is realized for the first time by monolithically integrating a mode demultiplexer, four MRR optical switches, and a mode multiplexer.

  11. Optical transmission properties of an anisotropic defect cavity in one-dimensional photonic crystal

    Science.gov (United States)

    Ouchani, Noama; El Moussaouy, Abdelaziz; Aynaou, Hassan; El Hassouani, Youssef; El Boudouti, El Houssaine; Djafari-Rouhani, Bahram

    2018-01-01

    We investigate theoretically the possibility to control the optical transmission in the visible and infrared regions by a defective one dimensional photonic crystal formed by a combination of a finite isotropic superlattice and an anisotropic defect layer. The Green's function approach has been used to derive the reflection and the transmission coefficients, as well as the densities of states of the optical modes. We evaluate the delay times of the localized modes and we compare their behavior with the total densities of states. We show that the birefringence of an anisotropic defect layer has a significant impact on the behavior of the optical modes in the electromagnetic forbidden bands of the structure. The amplitudes of the defect modes in the transmission and the delay time spectrum, depend strongly on the position of the cavity layer within the photonic crystal. The anisotropic defect layer induces transmission zeros in one of the two components of the transmission as a consequence of a destructive interference of the two polarized waves within this layer, giving rise to negative delay times for some wavelengths in the visible and infrared light ranges. This property is a typical characteristic of the anisotropic photonic layer and is without analogue in their counterpart isotropic defect layers. This structure offers several possibilities for controlling the frequencies, transmitted intensities and the delay times of the optical modes in the visible and infrared regions. It can be a good candidate for realizing high-precision optical filters.

  12. Physical model for the incoherent writing/erasure of cavity solitons in semiconductor optical amplifiers.

    Science.gov (United States)

    Barbay, S; Kuszelewicz, R

    2007-09-17

    We present a physical mechanism that explains the recent observations of incoherent writing and erasure of Cavity Solitons in a semiconductor optical amplifier [S. Barbay et al, Opt. Lett. 31, 1504-1506 (2006)]. This mechanism allows to understand the main observations of the experiment. In particular it perfectly explains why writing and erasure are possible as a result of a local perturbation in the carrier density, and why a delay is observed along with the writing process. Numerical simulations in 1D are performed and show very good qualitative agreement with the experimental observations.

  13. Aluminum Mirror Coatings for UVOIR Telescope Optics Including the Far UV

    Science.gov (United States)

    Balasubramanian, Kunjithapatha; Hennessy, John; Raouf, Nasrat; Nikzad, Shouleh; Ayala, Michael; Shaklan, Stuart; Scowen, Paul; Del Hoyo, Javier; Quijada, Manuel

    2015-01-01

    NASA Cosmic Origins (COR) Program identified the development of high reflectivity mirror coatings for large astronomical telescopes particularly for the far ultra violet (FUV) part of the spectrum as a key technology requiring significant materials research and process development. In this paper we describe the challenges and accomplishments in producing stable high reflectance aluminum mirror coatings with conventional evaporation and advanced Atomic Layer Deposition (ALD) techniques. We present the current status of process development with reflectance of approx. 55 to 80% in the FUV achieved with little or no degradation over a year. Keywords: Large telescope optics, Aluminum mirror, far UV astrophysics, ALD, coating technology development.

  14. Gain-assisted broadband ring cavity enhanced spectroscopy

    Science.gov (United States)

    Selim, Mahmoud A.; Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

    2017-02-01

    Incoherent broadband cavity enhanced spectroscopy can significantly increase the effective path length of light-matter interaction to detect weak absorption lines over broad spectral range, for instance to detect gases in confined environments. Broadband cavity enhancement can be based on the decay time or the intensity drop technique. Decay time measurement is based on using tunable laser source that is expensive and suffers from long scan time. Intensity dependent measurement is usually reported based on broadband source using Fabry-Perot cavity, enabling short measurement time but suffers from the alignment tolerance of the cavity and the cavity insertion loss. In this work we overcome these challenges by using an alignment-free ring cavity made of an optical fiber loop and a directional coupler, while having a gain medium pumped below the lasing threshold to improve the finesse and reduce the insertion loss. Acetylene (C2H2) gas absorption is measured around 1535 nm wavelength using a semiconductor optical amplifier (SOA) gain medium. The system is analyzed for different ring resonator forward coupling coefficient and loses, including the 3-cm long gas cell insertion loss and fiber connector losses used in the experimental verification. The experimental results are obtained for a coupler ratio of 90/10 and a fiber length of 4 m. The broadband source is the amplified spontaneous emission of another SOA and the output is measured using a 70pm-resolution optical spectrum analyzer. The absorption depth and the effective interaction length are improved about an order of magnitude compared to the direct absorption of the gas cell. The presented technique provides an engineering method to improve the finesse and, consequently the effective length, while relaxing the technological constraints on the high reflectivity mirrors and free-space cavity alignment.

  15. NO2 trace measurements by optical-feedback cavity-enhanced absorption spectroscopy

    Science.gov (United States)

    Ventrillard-Courtillot, I.; Foldes, T.; Romanini, D.

    2009-04-01

    In order to reach the sub-ppb NO2 detection level required for environmental applications in remote areas, we are developing a spectrometer that exploits a technique that we introduced several years ago, named Optical-Feedback Cavity-Enhanced Absorption Spectroscopy (OF-CEAS) [1]. It allows very sensitive and selective measurements, together with the realization of compact and robust set-ups as was subsequently demonstrated during measurements campaigns in harsh environments [2,3]. OF-CEAS benefits from the optical feedback (OF) to efficiently inject a cw-laser in a high finesse cavity (typically F >10 000). Absorption spectra are acquired on a small spectral region (~1 cm-1) that enables selective and quantitative measurements at a fast acquisition rate (~10 Hz) with a detection limit of several 10-10 cm-1 as reported in this paper. Spectra are obtained with high spectral resolution (~150 MHz) and are self calibrated by cavity rind-down measurements regularly performed (typically every second). Therefore, OF-CEAS appears very attractive for NO2 trace detection. This work is performed in the blue spectral region where NO2 has intense electronic transitions. Our setup involves a commercial extended cavity diode laser (ECDL) working at room temperature around 411nm. A first setup was developed [4] to demonstrate that OF sensitivity of ECDL is fully consistent with this technique, initially introduced with distributed feedback diode lasers in the near infrared region. In this paper we will report on a new set-up developed for in-situ measurements with proper mechanical, acoustic and thermal insulation. Additionally, new data processing was implemented allowing real time concentration measurements. It is based on a reference spectra recorded under controlled conditions by OF-CEAS and used later to fit the observed spectra. We will present measurements performed with calibrated NO2 reference samples demonstrating a good linearity of the apparatus. The minimum detectable

  16. 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.

  17. Possible influence of surface oxides on the optical response of high-purity niobium material used in the fabrication of superconducting radio frequency cavity

    Science.gov (United States)

    Singh, Nageshwar; Deo, M. N.; Roy, S. B.

    2016-09-01

    We have investigated the possible influence of surface oxides on the optical properties of a high-purity niobium (Nb) material for fabrication of superconducting radio frequency (SCRF) cavities. Various peaks in the infrared region were identified using Fourier transform infrared and Raman spectroscopy. Optical response functions such as complex refractive index, dielectric and conductivity of niobium were compared with the existing results on oxides free Nb and Cu. It was observed that the presence of a mixture of niobium-oxides, and probably near other surface impurities, appreciably influence the conducting properties of the material causing deviation from the typical metallic characteristics. In this way, the key result of this work is the observation, identification of vibrational modes of some of surface complexes and study of its influences on the optical responses of materials. This method of spectroscopic investigation will help in understanding the origin of degradation of performance of SCRF cavities.

  18. Possible influence of surface oxides on the optical response of high-purity niobium material used in the fabrication of superconducting radio frequency cavity

    International Nuclear Information System (INIS)

    Singh, Nageshwar; Deo, M.N.; Roy, S.B.

    2016-01-01

    We have investigated the possible influence of surface oxides on the optical properties of a high-purity niobium (Nb) material for fabrication of superconducting radio frequency (SCRF) cavities. Various peaks in the infrared region were identified using Fourier transform infrared and Raman spectroscopy. Optical response functions such as complex refractive index, dielectric and conductivity of niobium were compared with the existing results on oxides free Nb and Cu. It was observed that the presence of a mixture of niobium-oxides, and probably near other surface impurities, appreciably influence the conducting properties of the material causing deviation from the typical metallic characteristics. In this way, the key result of this work is the observation, identification of vibrational modes of some of surface complexes and study of its influences on the optical responses of materials. This method of spectroscopic investigation will help in understanding the origin of degradation of performance of SCRF cavities.

  19. Possible influence of surface oxides on the optical response of high-purity niobium material used in the fabrication of superconducting radio frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Nageshwar [Magnetic and Superconducting Materials Section, Raja Ramanna Centre for Advanced Technology, Indore 452013, M.P. (India); Deo, M.N. [High Pressure & Synchrotron Radiation Physics Division, BARC, Mumbai 400085 (India); Roy, S.B. [Magnetic and Superconducting Materials Section, Raja Ramanna Centre for Advanced Technology, Indore 452013, M.P. (India)

    2016-09-11

    We have investigated the possible influence of surface oxides on the optical properties of a high-purity niobium (Nb) material for fabrication of superconducting radio frequency (SCRF) cavities. Various peaks in the infrared region were identified using Fourier transform infrared and Raman spectroscopy. Optical response functions such as complex refractive index, dielectric and conductivity of niobium were compared with the existing results on oxides free Nb and Cu. It was observed that the presence of a mixture of niobium-oxides, and probably near other surface impurities, appreciably influence the conducting properties of the material causing deviation from the typical metallic characteristics. In this way, the key result of this work is the observation, identification of vibrational modes of some of surface complexes and study of its influences on the optical responses of materials. This method of spectroscopic investigation will help in understanding the origin of degradation of performance of SCRF cavities.

  20. High efficiency all-optical plasmonic diode based on a nonlinear side-coupled waveguide-cavity structure with broken symmetry

    Science.gov (United States)

    Liang, Hong-Qin; Liu, Bin; Hu, Jin-Feng; He, Xing-Dao

    2018-05-01

    An all-optical plasmonic diode, comprising a metal-insulator-metal waveguide coupled with a stub cavity, is proposed based on a nonlinear Fano structure. The key technique used is to break structural spatial symmetry by a simple reflector layer in the waveguide. The spatial asymmetry of the structure gives rise to the nonreciprocity of coupling efficiencies between the Fano cavity and waveguides on both sides of the reflector layer, leading to a nonreciprocal nonlinear response. Transmission properties and dynamic responses are numerically simulated and investigated by the nonlinear finite-difference time-domain method. In the proposed structure, high-efficiency nonreciprocal transmission can be achieved with a low power threshold and an ultrafast response time (subpicosecond level). A high maximum transmittance of 89.3% and an ultra-high transmission contrast ratio of 99.6% can also be obtained. The device can be flexibly adjusted for working wavebands by altering the stub cavity length.

  1. The HORUS Observatory - A Next Generation 2.4m UV-Optical Mission To Study Planetary, Stellar And Galactic Formation

    Science.gov (United States)

    Scowen, Paul A.; SDT, HORUS

    2013-01-01

    The High-ORbit Ultraviolet-visible Satellite (HORUS) is a 2.4-meter class UV-optical space telescope that will conduct a comprehensive and systematic study of the astrophysical processes and environments relevant for the births and life cycles of stars and their planetary systems, to investigate and understand the range of environments, feedback mechanisms, and other factors that most affect the outcome of the star and planet formation process. To do so, HORUS will provide 100 times greater imaging efficiency and more than 10 times greater UV spectroscopic sensitivity than has existed on the Hubble Space Telescope (HST). The HORUS mission will contribute vital information on how solar systems form and whether habitable planets should be common or rare. It also will investigate the structure, evolution, and destiny of galaxies and universe. This program relies on focused capabilities unique to space that no other planned NASA mission will provide: near-UV/visible (200-1075nm) wide-field, diffraction-limited imaging; and high-sensitivity, high-resolution UV (100-170nm) spectroscopy. The core HORUS design will provide wide field of view imagery and high efficiency point source FUV spectroscopy using a novel combination of spectral selection and field sharing. The HORUS Optical Telescope Assembly (OTA) design is based on modern light weight mirror technology with a faster primary mirror to shorten the overall package and thereby reduce mass. The OTA uses a three-mirror anastigmat configuration to provide excellent imagery over a large FOV - and is exactly aligned to use one of the recently released f/1.2 NRO OTAs as part of its design. The UV/optical Imaging Cameras use two 21k x 21k Focal Plane Arrays (FPAs). The FUV spectrometer uses cross strip anode based MCPs. This poster presents results from a 2010 design update requested by the NRC Decadal Survey, and reflects updated costs and technology to the original 2004 study. It is now one of the most mature 2.4m UVOIR

  2. Electrically Pumped Vertical-Cavity Amplifiers

    DEFF Research Database (Denmark)

    Greibe, Tine

    2007-01-01

    In this work, the design of electrically pumped vertical cavity semiconductor optical amplifiers (eVCAs) for use in a mode-locked external-cavity laser has been developed, investigated and analysed. Four different eVCAs, one top-emitting and three bottom emitting structures, have been designed...... and discussed. The thesis concludes with recommendations for further work towards the realisation of compact electrically pumped mode-locked vertical externalcavity surface emitting lasers....

  3. The UV and Laser Aging for PMMA/BDK/Azo-dye Polymer Blend Cured by UV Light Beams

    International Nuclear Information System (INIS)

    Ahmad, A A; Omari, A M

    2015-01-01

    A polymeric-based solution blend composed of Azo-dye methyl red (MR) doped with polymethelmethacrelate (PMMA) solution, in addition, to the BenzylDimethylKetal (BDK) photoinitiator was made with optimum molar ratios and deposited on glass substrate by spin coating technique. The samples were then exposed to UV light beams in order to assist the layers polymerization by the proper exposure process. The photo chemical reaction occurred during the UV light polymerization process induces photo refractive changes which were presented as a function of wavelength or photon energy. Two main strong absorption peaks were observed in the films at around 330 nm (3.75 eV) and 500 nm (2.48 eV) for different curing time periods. This phenomenon enhances the films usage for optical data storage media at these two wavelengths. Since the deposited films were then useful as based layers for Read/Write optical data storage media, they were then tested by UV or laser Read/Write beams independently. The optical properties of the films were investigated while exposed to each beam. Finally, their optical properties were investigated as a function of aging time in order to relate the temporary and/or permanent light-exposure effect on the films compared to their optical properties before the light exposure. The films show a low absorbance at 630 nm (1.97 eV) and high absorbance at 480 nm (2.58 eV). This fact makes it possible to record holographic gratings in the polymeric film upon light exposure. In all cases the optical properties were evaluated by using the very sensitive, non destructive surface testing spectroscopic ellipsometry technique. The films were characterized in the spectral range of 300 to 1000 nm using Lorentz oscillator model with one oscillator centred at 4.15 eV. This study has been supported by the SEM and EDAX results to investigate the effect of the UV and visible beams on their optical properties. The results of this research determined the proper conditions for

  4. Dynamics, OH distributions and UV emission of a gliding arc at various flow-rates investigated by optical measurements

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Sun, Zhiwei; Li, Zhongshan

    2014-01-01

    -state OH were investigated using planar laser-induced fluorescence. The results show that the shape, height, intensity and thickness of ground-state OH distribution vary significantly with air flow rates. Finally, UV emission of the gliding arc is measured using optical emission spectroscopy......We demonstrate a plasma discharge which is generated between two diverging electrodes and extended into a gliding arc in non-equilibrium condition by an air flow at atmospheric pressure. Effects of the air flow rates on the dynamics, ground-state OH distributions and spectral characterization of UV...

  5. Output field-quadrature measurements and squeezing in ultrastrong cavity-QED

    Science.gov (United States)

    Stassi, Roberto; Savasta, Salvatore; Garziano, Luigi; Spagnolo, Bernardo; Nori, Franco

    2016-12-01

    We study the squeezing of output quadratures of an electro-magnetic field escaping from a resonator coupled to a general quantum system with arbitrary interaction strengths. The generalized theoretical analysis of output squeezing proposed here is valid for all the interaction regimes of cavity-quantum electrodynamics: from the weak to the strong, ultrastrong, and deep coupling regimes. For coupling rates comparable or larger then the cavity resonance frequency, the standard input-output theory for optical cavities fails to calculate the variance of output field-quadratures and predicts a non-negligible amount of output squeezing, even if the system is in its ground state. Here we show that, for arbitrary interaction strength and for general cavity-embedded quantum systems, no squeezing can be found in the output-field quadratures if the system is in its ground state. We also apply the proposed theoretical approach to study the output squeezing produced by: (i) an artificial two-level atom embedded in a coherently-excited cavity; and (ii) a cascade-type three-level system interacting with a cavity field mode. In the latter case the output squeezing arises from the virtual photons of the atom-cavity dressed states. This work extends the possibility of predicting and analyzing the results of continuous-variable optical quantum-state tomography when optical resonators interact very strongly with other quantum systems.

  6. Determining Central Black Hole Masses in Distant Active Galaxies and Quasars. II. Improved Optical and UV Scaling Relationships

    DEFF Research Database (Denmark)

    Vestergaard, Marianne; Peterson, B. M.

    2006-01-01

    We present four improved empirical relationships useful for estimating the central black hole mass in nearby AGNs and distant luminous quasars alike using either optical or UV single-epoch spectroscopy. These mass-scaling relationships between line widths and luminosity are based on recently...

  7. Synthesis and Study of Optical Properties of Graphene/TiO2 Composites Using UV-VIS Spectroscopy

    Science.gov (United States)

    Rathod, P. B.; Waghuley, S. A.

    2016-09-01

    Graphene and TiO2 were synthesized using electrochemical exfoliation and co-precipitation methods, respectively. An ex situ approach was adopted for the graphene/TiO2 composites. The conformation of graphene in the TiO2 samples was examined through X-ray diffraction. Optical properties of the as-synthesised composites such as optical absorption, extinction coefficient, refractive index, real dielectric constant, imaginary dielectric constant, dissipation factor, and optical conductivity were measured using UV-Vis spectroscopy. The varying concentration of graphene in TiO2 affects the optical properties which appear different for 10 wt.% as compared to 5 wt.% graphene/ TiO2 composite. The composites exhibit an absorption peak at 300 nm with a decrease in band gap for 10 wt.% as compared to 5 wt.% graphene/TiO2 composite. The maximum optical conductivity for the graphene/TiO2 composite of 10 wt.% was found to be 1.86·10-2 Ω-1·m-1 at 300 nm.

  8. Inhibited emission of electromagnetic modes confined in subwavelength cavities

    International Nuclear Information System (INIS)

    Le Thomas, N.; Houdre, R.

    2011-01-01

    We experimentally demonstrate the active inhibition of subwavelength confined cavity modes emission and quality factor enhancement by controlling the cavity optical surrounding. The intrinsic radiation angular spectrum of modes confined in planar photonics crystal cavities as well as its modifications depending on the environment are inferred via a transfer matrix modeling and k-space imaging.

  9. Laser cooling of neutral atoms by red-shifted diffuse light in an optical integral sphere cavity

    International Nuclear Information System (INIS)

    Wang Yuzhu; Chen Hongxin; Cai Weiquan; Liu Liang; Zhou Shanyu; Shu Wei; Li Fosheng

    1994-01-01

    In this paper, we report a cooling and deceleration experiment of a thermal beam by using a nearly resonant red-shifted diffuse light in an optical integral sphere cavity. With this red-shifted diffuse light, a part of thermal sodium atoms is cooled to 380m/s and the velocity width of cooled atoms is about 20m/s. The mechanism of this kind of laser cooling and the experimental results are discussed. (author). 12 refs, 5 figs

  10. Design of a high-power Nd:YAG Q-switched laser cavity

    Science.gov (United States)

    Singh, Ikbal; Kumar, Avinash; Nijhawan, O. P.

    1995-06-01

    An electro-optically Q-switched Nd:YAG laser resonator that uses two end prisms placed orthogonally perpendicular to each other has been designed. This configuration improves the stability of the resonator and does not alter the characteristics of the electro-optical Q switch. The outcoupling ratio of the cavity is optimized by a change in the azimuthal angle of a phase-matched Porro prism placed at one end of the cavity. The prism placed at the other end of the cavity is designed so that it introduces a phase change of Pi , regardless of its orientation and index of refraction, resulting in a more efficient and stable cavity.

  11. Photon-Induced Spin-Orbit Coupling in Ultracold Atoms inside Optical Cavity

    Directory of Open Access Journals (Sweden)

    Lin Dong

    2015-05-01

    Full Text Available We consider an atom inside a ring cavity, where a plane-wave cavity field together with an external coherent laser beam induces a two-photon Raman transition between two hyperfine ground states of the atom. This cavity-assisted Raman transition induces effective coupling between atom’s internal degrees of freedom and its center-of-mass motion. In the meantime, atomic dynamics exerts a back-action to cavity photons. We investigate the properties of this system by adopting a mean-field and a full quantum approach, and show that the interplay between the atomic dynamics and the cavity field gives rise to intriguing nonlinear phenomena.

  12. Observation of single quantum dots in GaAs/AlAs micropillar cavities

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Philipp; Karl, Matthias; Hu, Dongzhi; Schaadt, Daniel M.; Kalt, Heinz; Hetterich, Michael [Institut fuer Angewandte Physik, Universitaet Karlsruhe (Germany); DFG Center for Functional Nanostructures (CFN), Karlsruhe (Germany)

    2009-07-01

    In our contribution we present the fabrication steps of micropillar cavities and their optical properties. The layer structure consisting of a GaAs-based lambda-cavity sandwiched between two GaAs/AlAs distributed Bragg reflectors is grown by molecular-beam epitaxy. In(Ga)As quantum dots, emitting at around 950 nm, are embedded as optically active medium in the middle of the cavity. The pillars are milled out of this structure with a focused ion-beam. A confocal micro-photoluminescence set-up allows to measure optical cavity modes as well as single quantum dots in the pillars when using low excitation intensity. This enables us to observe a (thermal) shift of the single quantum dot peaks relative to the cavity mode. In addition, we increased the numerical aperture of the set-up (originally 0.4) with a solid immersion lens up to 0.8. Thus we are able to detect the fundamental mode of pillars with very small diameters. Furthermore, the collection efficiency increases substantially.

  13. Frequency and time domain analysis of an external cavity laser with strong filtered optical feedback

    DEFF Research Database (Denmark)

    Detoma, Enrico; Tromborg, Bjarne; Montrosset, Ivo

    The stability properties of an external cavity laser with strong grating-filtered optical feedback to an anti-reflection coated facet are studied with a general frequency domain model. The model takes into account non-linear effects like four wave mixing and gain compression. A small......-signal analysis in the frequency domain allows a calculation of the range of operation without mode hopping around the grating reflectivity peak. This region should be as large as possible for proper operation of the tunable laser source. The analysis shows this stabilizing effect of mode coupling and gain...

  14. Stable optical soliton in the ring-cavity fiber system with carbon nanotube as saturable absorber

    Science.gov (United States)

    Li, Bang-Qing; Ma, Yu-Lan; Yang, Tie-Mei

    2018-01-01

    Main attention focuses on the theoretical study of the ring-cavity fiber laser system with carbon nanotubes (CNT) as saturable absorber (SA). The system is modelled as a non-standard Schrödinger equation with the coefficients blended real and imaginary numbers. New stable exact soliton solution is constructed by the bilinear transformation method for the system. The influences of the key parameters related to CNTs and SA on the optical pulse soliton are discussed in simulation. The soliton amplitude and phase can be tuned by choosing suitable parameters.

  15. Chaos synchronization in vertical-cavity surface-emitting laser based on rotated polarization-preserved optical feedback.

    Science.gov (United States)

    Nazhan, Salam; Ghassemlooy, Zabih; Busawon, Krishna

    2016-01-01

    In this paper, the influence of the rotating polarization-preserved optical feedback on the chaos synchronization of a vertical-cavity surface-emitting laser (VCSEL) is investigated experimentally. Two VCSELs' polarization modes (XP) and (YP) are gradually rotated and re-injected back into the VCSEL. The anti-phase dynamics synchronization of the two polarization modes is evaluated using the cross-correlation function. For a fixed optical feedback, a clear relationship is found between the cross-correlation coefficient and the polarization angle θp. It is shown that high-quality anti-phase polarization-resolved chaos synchronization is achieved at higher values of θp. The maximum value of the cross-correlation coefficient achieved is -0.99 with a zero time delay over a wide range of θp beyond 65° with a poor synchronization dynamic at θp less than 65°. Furthermore, it is observed that the antiphase irregular oscillation of the XP and YP modes changes with θp. VCSEL under the rotating polarization optical feedback can be a good candidate as a chaotic synchronization source for a secure communication system.

  16. Mirror coatings for large aperture UV optical infrared telescope optics

    Science.gov (United States)

    Balasubramanian, Kunjithapatham; Hennessy, John; Raouf, Nasrat; Nikzad, Shouleh; Del Hoyo, Javier; Quijada, Manuel

    2017-09-01

    Large space telescope concepts such as LUVOIR and HabEx aiming for observations from far UV to near IR require advanced coating technologies to enable efficient gathering of light with important spectral signatures including those in far UV region down to 90nm. Typical Aluminum mirrors protected with MgF2 fall short of the requirements below 120nm. New and improved coatings are sought to protect aluminum from oxidizing readily in normal environment causing severe absorption and reduction of reflectance in the deep UV. Choice of materials and the process of applying coatings present challenges. Here we present the progress achieved to date with experimental investigations of coatings at JPL and at GSFC and discuss the path forward to achieve high reflectance in the spectral region from 90 to 300nm without degrading performance in the visible and NIR regions taking into account durability concerns when the mirrors are exposed to normal laboratory environment as well as high humidity conditions. Reflectivity uniformity required on these mirrors is also discussed.

  17. Optical Protection Filters for Harmful Laser Beams and UV Radiation

    Science.gov (United States)

    Azim M., Osama A.

    2007-02-01

    Due to the rapid growth of radiation protection applications in various devices and instruments, it is essential to use suitable filters for eye protection of the personal working in the radiation field. Different protection filters were produced to protect from four laser beam wavelengths (at 532nm, 632.8nm, 694nm and 1064nm) and block three UV bands (UVA, UVB, and UVC). The design structure of the required dielectric multilayer filters used optical thin film technology. The computer analyses of the multilayer filter formulas were prepared using Macleod Software for the production filter processes. The deposition technique was achieved on optical substrates (Glass BK-7 and Infrasil 301) by dielectric material combinations including Dralo (mixture of oxides TiO2/Al2O3), and Lima (mixture of oxides SiO2/Al2O3); deposition by an electron beam gun. The output transmittance curves for both theoretical and experimental values of all filters are presented. To validate the suitability for use in a `real world', rather than laboratory test application, full environmental assessment was also carried out. These filters exhibited high endurance after exposing them to the durability tests (adhesion, abrasion resistance and humidity) according to military standards MIL-C-675C and MIL-C-48497A.

  18. Optical Protection Filters for Harmful Laser Beams and UV Radiation

    International Nuclear Information System (INIS)

    Azim M, Osama A.

    2007-01-01

    Due to the rapid growth of radiation protection applications in various devices and instruments, it is essential to use suitable filters for eye protection of the personal working in the radiation field. Different protection filters were produced to protect from four laser beam wavelengths (at 532nm, 632.8nm, 694nm and 1064nm) and block three UV bands (UVA, UVB, and UVC). The design structure of the required dielectric multilayer filters used optical thin film technology. The computer analyses of the multilayer filter formulas were prepared using Macleod Software for the production filter processes. The deposition technique was achieved on optical substrates (Glass BK-7 and Infrasil 301) by dielectric material combinations including Dralo (mixture of oxides TiO2/Al2O3), and Lima (mixture of oxides SiO2/Al2O3); deposition by an electron beam gun. The output transmittance curves for both theoretical and experimental values of all filters are presented. To validate the suitability for use in a 'real world', rather than laboratory test application, full environmental assessment was also carried out. These filters exhibited high endurance after exposing them to the durability tests (adhesion, abrasion resistance and humidity) according to military standards MIL-C-675C and MIL-C-48497A

  19. Cavity Ring-down Spectroscopic System And Method

    KAUST Repository

    Alquaity, Awad Bin Saud

    2015-05-14

    A system and method for cavity ring-down spectroscopy can include a pulsed quantum cascade laser, an optical ring-down cavity, a photodetector, and an oscilloscope. The system and method can produce pulse widths of less than 200 ns with bandwidths greater than 300 pm, as well as provide temporal resolution of greater than 10 .mu.s.

  20. Cavity Ring-down Spectroscopic System And Method

    KAUST Repository

    Alquaity, Awad Bin Saud; Farooq, Aamir

    2015-01-01

    A system and method for cavity ring-down spectroscopy can include a pulsed quantum cascade laser, an optical ring-down cavity, a photodetector, and an oscilloscope. The system and method can produce pulse widths of less than 200 ns with bandwidths greater than 300 pm, as well as provide temporal resolution of greater than 10 .mu.s.

  1. Swift Monitoring of NGC 4151: Evidence for a Second X-Ray/UV Reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Edelson, R. [University of Maryland, Department of Astronomy, College Park, MD 20742-2421 (United States); Gelbord, J. [Spectral Sciences Inc., 4 Fourth Avenue, Burlington, MA 01803 (United States); Cackett, E. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock Street, Detroit, MI 48201 (United States); Connolly, S.; McHardy, I. [University of Southampton, Highfield, Southampton, SO17 1BJ (United Kingdom); Done, C.; Gardner, E. [University of Durham, Center for Extragalactic Astronomy, Department of Physics, South Road, Durham, DH1 3LE (United Kingdom); Fausnaugh, M.; Peterson, B. M. [The Ohio State University, Department of Astronomy, 140 W 18th Avenue, Columbus, OH 43210 (United States); Gehrels, N. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Goad, M.; Vaughan, S. [University of Leicester, Department of Physics and Astronomy, Leicester, LE1 7RH (United Kingdom); Horne, K. [SUPA Physics and Astronomy, University of St. Andrews, Fife, KY16 9SS Scotland (United Kingdom); Vestergaard, M. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Breeveld, A. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Barth, A. J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Bentz, M. [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 605, Atlanta, GA 30303 (United States); Bottorff, M. [Physics Department, Southwestern University, Georgetown, TX 78626 (United States); Brandt, W. N. [Department of Astronomy and Astrophysics, Eberly College of Science, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802 (United States); Crawford, S. M. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935, Cape Town (South Africa); and others

    2017-05-01

    Swift monitoring of NGC 4151 with an ∼6 hr sampling over a total of 69 days in early 2016 is used to construct light curves covering five bands in the X-rays (0.3–50 keV) and six in the ultraviolet (UV)/optical (1900–5500 Å). The three hardest X-ray bands (>2.5 keV) are all strongly correlated with no measurable interband lag, while the two softer bands show lower variability and weaker correlations. The UV/optical bands are significantly correlated with the X-rays, lagging ∼3–4 days behind the hard X-rays. The variability within the UV/optical bands is also strongly correlated, with the UV appearing to lead the optical by ∼0.5–1 days. This combination of ≳3 day lags between the X-rays and UV and ≲1 day lags within the UV/optical appears to rule out the “lamp-post” reprocessing model in which a hot, X-ray emitting corona directly illuminates the accretion disk, which then reprocesses the energy in the UV/optical. Instead, these results appear consistent with the Gardner and Done picture in which two separate reprocessings occur: first, emission from the corona illuminates an extreme-UV-emitting toroidal component that shields the disk from the corona; this then heats the extreme-UV component, which illuminates the disk and drives its variability.

  2. The application of UV LEDs for differential optical absorption spectroscopy

    Science.gov (United States)

    Geiko, Pavel P.; Smirnov, Sergey S.; Samokhvalov, Ignatii V.

    2018-04-01

    Modern UV LEDs represent a potentially very advantageous alternative to thermal light sources, in particular xenon arc lamps, which are the most common light sources in trace gas-analyzers. So, the light-emitting diodes are very attractive for use of as light sources for Long Path Differential Optical Absorption Spectroscopy (DOAS) measurements of trace gases in the open atmosphere. Recent developments in fibre-coupling telescope technology and the availability of ultraviolet light emitting diodes have now allowed us to construct a portable, long path DOAS instrument for use at remote locations and specifically for measuring degassing from active volcanic systems. First of all, we are talking about the measurement of sulphur dioxide, carbon disulphide and, oxides of chlorine and bromine. The parallel measurements of sulfur dioxide using a certified gas analyzer, were conducted and showed good correlation.

  3. Initial Technology Assessment for the Large UV-Optical-Infrared (LUVOIR) Mission Concept Study

    Science.gov (United States)

    Bolcar, Matthew R.; Feinberg, Lee D.; France, Kevin; Rauscher, Bernard J.; Redding, David; Schiminovich, David

    2016-01-01

    The NASA Astrophysics Divisions 30-Year Roadmap prioritized a future large-aperture space telescope operating in the ultra-violet-optical-infrared wavelength regime. The Association of Universities for Research in Astronomy envisioned a similar observatory, the High Definition Space Telescope. And a multi-institution group also studied the Advanced Technology Large Aperture Space Telescope. In all three cases, a broad science case is outlined, combining general astrophysics with the search for bio-signatures via direct-imaging and spectroscopic characterization of habitable exo-planets. We present an initial technology assessment that enables such an observatory that is currently being studied for the 2020 Decadal Survey by the Large UV-Optical Infrared (LUVOIR) surveyor Science and Technology Definition Team. We present here the technology prioritization for the 2016 technology cycle and define the required technology capabilities and current state-of-the-art performance. Current, planned, and recommended technology development efforts are also reported.

  4. Measurements of UV aerosol optical depth in the French Southern Alps

    Directory of Open Access Journals (Sweden)

    J. Lenoble

    2008-11-01

    Full Text Available Routine measurements of global and diffuse UV irradiances at Briançon station (1310 m a.s.l. are used to retrieve the direct solar irradiance and the aerosol optical depth (AOD, for cloudless days. Data of three years (2003, 2004, 2005 are analyzed; the results confirm those of a preliminary analysis for 2001, 2002.

    The atmosphere is very clear in winter, with AODs between 0.05 and 0.1. The turbidity increases slowly in spring, starting end of February, with AODs around 0.2–0.3 in mid summer, some values reaching 0.4. A similar behaviour is observed for all years, with somewhat higher values in late summer for the year 2003.

  5. Measurements and estimation of the columnar optical depth of tropospheric aerosols in the UV spectral region

    Directory of Open Access Journals (Sweden)

    V. E. Cachorro

    2002-04-01

    Full Text Available We report values of the columnar tropospheric aerosol optical depth at UV wavelengths based on experimental measurements of the direct spectral irradiances carried out by a commercial spectroradiometer (Li1800 of Licor company covering the range from 300–1100 nm at two stations with different climate characteristics in Spain. The first station is located in a rural site in north central Spain with continental climate. The data extend from March to the end of October of 1995. The other station is a coastal site in the Gulf of Cádiz (southwest Spain of maritime climate type. This study is mainly focused on the capability of estimating aerosol optical depth values in the UV region based on the extracted information in the visible and near infrared ranges. A first method has been used based on the Ångström turbidity parameters. However, since this method requires detailed spectral information, a second method has also been used, based on the correlation between wavelengths. A correlation has been established between the experimental aerosol optical depth values at 350 nm and 500 nm wavelengths. Although the type of aerosol seems to be the key factor that determines the quality of these estimations, the evaluation of the associated error is necessary to know the behaviour of these estimations in each area of study.Key words. Atmospheric composition and structure (aerosols and particles; transmission and scattering of radiation; troposphere – composition and chemistry

  6. Measurements and estimation of the columnar optical depth of tropospheric aerosols in the UV spectral region

    Directory of Open Access Journals (Sweden)

    V. E. Cachorro

    Full Text Available We report values of the columnar tropospheric aerosol optical depth at UV wavelengths based on experimental measurements of the direct spectral irradiances carried out by a commercial spectroradiometer (Li1800 of Licor company covering the range from 300–1100 nm at two stations with different climate characteristics in Spain. The first station is located in a rural site in north central Spain with continental climate. The data extend from March to the end of October of 1995. The other station is a coastal site in the Gulf of Cádiz (southwest Spain of maritime climate type. This study is mainly focused on the capability of estimating aerosol optical depth values in the UV region based on the extracted information in the visible and near infrared ranges. A first method has been used based on the Ångström turbidity parameters. However, since this method requires detailed spectral information, a second method has also been used, based on the correlation between wavelengths. A correlation has been established between the experimental aerosol optical depth values at 350 nm and 500 nm wavelengths. Although the type of aerosol seems to be the key factor that determines the quality of these estimations, the evaluation of the associated error is necessary to know the behaviour of these estimations in each area of study.

    Key words. Atmospheric composition and structure (aerosols and particles; transmission and scattering of radiation; troposphere – composition and chemistry

  7. Spectral properties of a broad-area diode laser with off-axis external-cavity feedback

    DEFF Research Database (Denmark)

    Chi, Mingjun; Petersen, Paul Michael

    2013-01-01

    Spectral properties, both the optical spectrum and the intensity noise spectrum, of a broad-area diode laser with off-axis external-cavity feedback are presented. We show that the optical spectrum of the diode laser system is shifted to longer wavelengths due to the external-cavity feedback....... The intensity noise spectrum of the diode laser shows that the intensity noise is increased strongly by the external-cavity feedback. External-cavity modes are excited in the external cavity even in the off-axis configuration. The peak spacing of the intensity noise spectrum shows that single roundtrip external......-cavity modes are excited. We believe that the four-wave mixing process in the broad-area diode laser is responsible for the establishment of the external-cavity mode....

  8. Wavelength-controlled external-cavity laser with a silicon photonic crystal resonant reflector

    Science.gov (United States)

    Gonzalez-Fernandez, A. A.; Liles, Alexandros A.; Persheyev, Saydulla; Debnath, Kapil; O'Faolain, Liam

    2016-03-01

    We report the experimental demonstration of an alternative design of external-cavity hybrid lasers consisting of a III-V Semiconductor Optical Amplifier with fiber reflector and a Photonic Crystal (PhC) based resonant reflector on SOI. The Silicon reflector comprises a polymer (SU8) bus waveguide vertically coupled to a PhC cavity and provides a wavelength-selective optical feedback to the laser cavity. This device exhibits milliwatt-level output power and sidemode suppression ratio of more than 25 dB.

  9. Enhanced optical transmission through a star-shaped bull's eye at dual resonant-bands in UV and the visible spectral range.

    Science.gov (United States)

    Nazari, Tavakol; Khazaeinezhad, Reza; Jung, Woohyun; Joo, Boram; Kong, Byung-Joo; Oh, Kyunghwan

    2015-07-13

    Dual resonant bands in UV and the visible range were simultaneously observed in the enhanced optical transmission (EOT) through star-shaped plasmonic structures. EOTs through four types of polygonal bull's eyes with a star aperture surrounded by the concentric star grooves were analyzed and compared for 3, 4, 5, and 6 corners, using finite difference time domain (FDTD) method. In contrast to plasmonic resonances in the visible range, the UV-band resonance intensity was found to scale with the number of corners, which is related with higher order multipole interactions. Spectral positions and relative intensities of the dual resonances were analyzed parametrically to find optimal conditions to maximize EOT in UV-visible dual bands.

  10. Quantitative Detection of Singlet O2 by Cavity-Enhanced Absorption

    National Research Council Canada - National Science Library

    Williams, Skip; Gupta, Manish; Owano, Thomas; Baer, Douglas S; O'Keefe, Anthony; Yarkony, David R; Matsika, Spiridoula

    2004-01-01

    .... The method is based on sensitive off-axis integrated-cavity-output spectroscopy (ICOS). Off-axis ICOS allows narrowband, continuous-wave lasers to be used in conjunction with optical cavities to record sensitive absorption measurements...

  11. Continuous-wave cavity ringdown spectroscopy based on the control of cavity reflection.

    Science.gov (United States)

    Li, Zhixin; Ma, Weiguang; Fu, Xiaofang; Tan, Wei; Zhao, Gang; Dong, Lei; Zhang, Lei; Yin, Wangbao; Jia, Suotang

    2013-07-29

    A new type of continuous-wave cavity ringdown spectrometer based on the control of cavity reflection for trace gas detection was designed and evaluated. The technique separated the acquisitions of the ringdown event and the trigger signal to optical switch by detecting the cavity reflection and transmission, respectively. A detailed description of the time sequence of the measurement process was presented. In order to avoid the wrong extraction of ringdown time encountered accidentally in fitting procedure, the laser frequency and cavity length were scanned synchronously. Based on the statistical analysis of measured ringdown times, the frequency normalized minimum detectable absorption in the reflection control mode was 1.7 × 10(-9)cm(-1)Hz(-1/2), which was 5.4 times smaller than that in the transmission control mode. However the signal-to-noise ratio of the absorption spectrum was only 3 times improved since the etalon effect existed. Finally, the peak absorption coefficients of the C(2)H(2) transition near 1530.9nm under different pressures showed a good agreement with the theoretical values.

  12. Flare activity on UV CETI: visible and IUE observations

    International Nuclear Information System (INIS)

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-06-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU = 2sup(m) but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings. The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  13. UV laser cleaving of air-polymer structured fibre

    NARCIS (Netherlands)

    Canning, J.; Buckley, E.; Groothoff, N.; Luther-Davies, B.; Zagari, J.

    2002-01-01

    The demonstration of ultraviolet (UV) laser ablation technique for cleaving of air-polymer structure (APF) fiber was presented. ArF exciplex laser with an unstable resonator cavity with pulse-to-pulse intensity fluctuations was used for the study. The thermal diffusion time across a 200 µm diameter

  14. Optical fiber spectrophotometer

    International Nuclear Information System (INIS)

    Zhuang Weixin; Tian Guocheng; Ye Guoan; Zhou Zhihong; Cheng Weiwei; Huang Lifeng; Liu Suying; Tang Yanji; Hu Jingxin; Zhao Yonggang

    1998-12-01

    A method called 'Two Arm's Photo out and Electricity Send-back' is introduced. UV-365 UV/VIS/NIR spectrophotometer has been reequipped by this way with 5 meters long optical fiber. Another method called 'One Arm's Photo out and Photo Send-back' is also introduced. λ 19 UV/VIS/NIR spectrophotometer has been reequipped by this way with 10 meters long optical fiber. Optical fiber spectrophotometer can work as its main set. So it is particularly applicable to radio activity work

  15. Single atoms on demand for cavity QED experiments

    International Nuclear Information System (INIS)

    Dotsenko, I.

    2007-01-01

    Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the cavity

  16. Single atoms on demand for cavity QED experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, I.

    2007-09-06

    Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the

  17. Dynamics of bad-cavity-enhanced interaction with cold Sr atoms for laser stabilization

    DEFF Research Database (Denmark)

    Schäffer, S. A.; Christensen, B. T.R.; Henriksen, M. R.

    2017-01-01

    Hybrid systems of cold atoms and optical cavities are promising systems for increasing the stability of laser oscillators used in quantum metrology and atomic clocks. In this paper we map out the atom-cavity dynamics in such a system and demonstrate limitations as well as robustness of the approach....... We investigate the phase response of an ensemble of cold Sr88 atoms inside an optical cavity for use as an error signal in laser frequency stabilization. With this system we realize a regime where the high atomic phase shift limits the dynamical locking range. The limitation is caused by the cavity...

  18. Reconfiguration of the multiwavelength operation of optical fiber ring lasers by the modifiable intra-cavity induced losses of an in-fiber tip probe modal Michelson interferometer

    Science.gov (United States)

    Salceda-Delgado, G.; Martinez-Rios, A.; Sierra-Hernandez, J. M.; Rodríguez-Carreón, V. C.; Toral-Acosta, D.; Selvas-Aguilar, R.; Álvarez-Tamayo, R. I.; Castillo-Guzman, A. A.; Rojas-Laguna, R.

    2018-03-01

    A straightforward and versatile method for switching from single to different multiwavelength laser emission in ring cavity fiber lasers is proposed and demonstrated experimentally. The method is based on using the changeable interference pattern from an optical fiber modal Michelson interferometer as a wavelength selective filter into the ring cavity laser. The interferometer is constructed using a bi-conical tapered fiber and a single-mode fiber segment, with these being spliced together to form an optical fiber tip probe. When the length of the single-mode fiber piece is modified, the phase difference between the interfering modes of the interferometer causes a change in the interferometer free spectral range. As a consequence, the laser intra-cavity losses lead to gain competition, which allows us to adjust the number of simultaneously generated laser lines. A multiwavelength reconfiguration of the laser from one up to a maximum of eight emission lines was obtained, with a maximum SNR of around 47 dBm.

  19. Evanescent-wave and ambient chiral sensing by signal-reversing cavity ringdown polarimetry.

    Science.gov (United States)

    Sofikitis, Dimitris; Bougas, Lykourgos; Katsoprinakis, Georgios E; Spiliotis, Alexandros K; Loppinet, Benoit; Rakitzis, T Peter

    2014-10-02

    Detecting and quantifying chirality is important in fields ranging from analytical and biological chemistry to pharmacology and fundamental physics: it can aid drug design and synthesis, contribute to protein structure determination, and help detect parity violation of the weak force. Recent developments employ microwaves, femtosecond pulses, superchiral light or photoionization to determine chirality, yet the most widely used methods remain the traditional methods of measuring circular dichroism and optical rotation. However, these signals are typically very weak against larger time-dependent backgrounds. Cavity-enhanced optical methods can be used to amplify weak signals by passing them repeatedly through an optical cavity, and two-mirror cavities achieving up to 10(5) cavity passes have enabled absorption and birefringence measurements with record sensitivities. But chiral signals cancel when passing back and forth through a cavity, while the ubiquitous spurious linear birefringence background is enhanced. Even when intracavity optics overcome these problems, absolute chirality measurements remain difficult and sometimes impossible. Here we use a pulsed-laser bowtie cavity ringdown polarimeter with counter-propagating beams to enhance chiral signals by a factor equal to the number of cavity passes (typically >10(3)); to suppress the effects of linear birefringence by means of a large induced intracavity Faraday rotation; and to effect rapid signal reversals by reversing the Faraday rotation and subtracting signals from the counter-propagating beams. These features allow absolute chiral signal measurements in environments where background subtraction is not feasible: we determine optical rotation from α-pinene vapour in open air, and from maltodextrin and fructose solutions in the evanescent wave produced by total internal reflection at a prism surface. The limits of the present polarimeter, when using a continuous-wave laser locked to a stable, high

  20. Cavity-enhanced resonant tunneling photodetector at telecommunication wavelengths

    International Nuclear Information System (INIS)

    Pfenning, Andreas; Hartmann, Fabian; Langer, Fabian; Höfling, Sven; Kamp, Martin; Worschech, Lukas

    2014-01-01

    An AlGaAs/GaAs double barrier resonant tunneling diode (RTD) with a nearby lattice-matched GaInNAs absorption layer was integrated into an optical cavity consisting of five and seven GaAs/AlAs layers to demonstrate cavity enhanced photodetection at the telecommunication wavelength 1.3 μm. The samples were grown by molecular beam epitaxy and RTD-mesas with ring-shaped contacts were fabricated. Electrical and optical properties were investigated at room temperature. The detector shows maximum photocurrent for the optical resonance at a wavelength of 1.29 μm. At resonance a high sensitivity of 3.1×10 4 A/W and a response up to several pA per photon at room temperature were found

  1. Numerical demonstration of neuromorphic computing with photonic crystal cavities.

    Science.gov (United States)

    Laporte, Floris; Katumba, Andrew; Dambre, Joni; Bienstman, Peter

    2018-04-02

    We propose a new design for a passive photonic reservoir computer on a silicon photonics chip which can be used in the context of optical communication applications, and study it through detailed numerical simulations. The design consists of a photonic crystal cavity with a quarter-stadium shape, which is known to foster interesting mixing dynamics. These mixing properties turn out to be very useful for memory-dependent optical signal processing tasks, such as header recognition. The proposed, ultra-compact photonic crystal cavity exhibits a memory of up to 6 bits, while simultaneously accepting bitrates in a wide region of operation. Moreover, because of the inherent low losses in a high-Q photonic crystal cavity, the proposed design is very power efficient.

  2. Optical Injection Locking of Vertical Cavity Surface-Emitting Lasers: Digital and Analog Applications

    Science.gov (United States)

    Parekh, Devang

    With the rise of mobile (cellphones, tablets, notebooks, etc.) and broadband wireline communications (Fiber to the Home), there are increasing demands being placed on transmitters for moving data from device to device and around the world. Digital and analog fiber-optic communications have been the key technology to meet this challenge, ushering in ubiquitous Internet and cable TV over the past 20 years. At the physical layer, high-volume low-cost manufacturing of semiconductor optoelectronic devices has played an integral role in allowing for deployment of high-speed communication links. In particular, vertical cavity surface emitting lasers (VCSEL) have revolutionized short reach communications and are poised to enter more markets due to their low cost, small size, and performance. However, VCSELs have disadvantages such as limited modulation performance and large frequency chirp which limits fiber transmission speed and distance, key parameters for many fiber-optic communication systems. Optical injection locking is one method to overcome these limitations without re-engineering the VCSEL at the device level. By locking the frequency and phase of the VCSEL by the direct injection of light from another laser oscillator, improved device performance is achieved in a post-fabrication method. In this dissertation, optical injection locking of VCSELs is investigated from an applications perspective. Optical injection locking of VCSELs can be used as a pathway to reduce complexity, cost, and size of both digital and analog fiber-optic communications. On the digital front, reduction of frequency chirp via bit pattern inversion for large-signal modulation is experimentally demonstrated showing up to 10 times reduction in frequency chirp and over 90 times increase in fiber transmission distance. Based on these results, a new reflection-based interferometric model for optical injection locking was established to explain this phenomenon. On the analog side, the resonance

  3. Flare activity on UV Ceti: visible and IUE observations

    International Nuclear Information System (INIS)

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-01-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU=2 mag but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings (∼ 100 km s -1 ). The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  4. Hybrid fiber grating cavity for multi-parametric sensing.

    Science.gov (United States)

    Paladino, Domenico; Quero, Giuseppe; Caucheteur, Christophe; Mégret, Patrice; Cusano, Andrea

    2010-05-10

    We propose an all-fiber hybrid cavity involving two unbalanced uniform fiber Bragg gratings (FBGs) written at both sides of a tilted FBG (TFBG) to form an all-fiber interferometer. This configuration provides a wavelength gated reflection signal with interference fringes depending on the cavity features modulated by spectral dips associated to the wavelength dependent optical losses due to cladding mode coupling occurring along the TFBG. Such a robust structure preserves the advantages of uniform FBGs in terms of interrogation methods and allows the possibility of simultaneous physical and chemical sensing. (c) 2010 Optical Society of America.

  5. Coupled quantum electrodynamics in photonic crystal cavities towards controlled phase gate operations

    International Nuclear Information System (INIS)

    Xiao, Y-F; Gao, J; McMillan, J F; Yang, X; Wong, C W; Zou, X-B; Chen, Y-L; Han, Z-F; Guo, G-C

    2008-01-01

    In this paper, a scalable photonic crystal cavity array, in which single embedded quantum dots (QDs) are coherently interacting, is studied theoretically. Firstly, we examine the spectral character and optical delay brought about by the coupled cavities interacting with single QDs, in an optical analogue to electromagnetically induced transparency. Secondly, we then examine the usability of this coupled QD-cavity system for quantum phase gate operation and our numerical examples suggest that a two-qubit system with fidelity above 0.99 and photon loss below 0.04 is possible.

  6. Deep-ultraviolet cavity ringdown spectroscopy

    NARCIS (Netherlands)

    Sneep, M.C.; Hannemann, S.; van Duijn, E.J.; Ubachs, W.M.G.

    2004-01-01

    The sensitive optical detection technique of cavity ringdown spectroscopy is extended to the wavelength range 197-204 nm. A novel design narrowband Fourier-transform-limited laser is used, and the technique is applied to gas-phase extinction measurements in CO

  7. Resonant cavity enhanced multi-analyte sensing

    Science.gov (United States)

    Bergstein, David Alan

    Biological research and medicine increasingly depend on interrogating binding interactions among small segments of DNA, RNA, protein, and bio-specific small molecules. Microarray technology, which senses the affinity for target molecules in solution for a multiplicity of capturing agents fixed to a surface, has been used in biological research for gene expression profiling and in medicine for molecular biomarker detection. Label-free affinity sensing is preferable as it avoids fluorescent labeling of the target molecules, reducing test cost and variability. The Resonant Cavity Imaging Biosensor (RCIB) is a label-free optical inference based technique introduced that scales readily to high throughput and employs an optical resonant cavity to enhance sensitivity by a factor of 100 or more. Near-infrared light centered at 1512.5 nm couples resonantly through a cavity constructed from Si/SiO2 Bragg reflectors, one of which serves as the binding surface. As the wavelength is swept 5 nm, an Indium-Gallium-Arsenide digital camera monitors cavity transmittance at each pixel with resolution 128 x 128. A wavelength shift in the local resonant response of the optical cavity indicates binding. Positioning the sensing surface with respect to the standing wave pattern of the electric field within the cavity, one can control the sensitivity of the measurement to the presence of bound molecules thereby enhancing or suppressing sensitivity where appropriate. Transmitted intensity at thousands of pixel locations are recorded simultaneously in a 10 s, 5 nm scan. An initial proof-of-principle setup was constructed. A sample was fabricated with 25, 100 mum wide square regions, each with a different density of 1 mum square depressions etched 12 nm into the S1O 2 surface. The average depth of each etched region was found with 0.05 nm RMS precision when the sample remains loaded in the setup and 0.3 nm RMS precision when the sample is removed and replaced. Selective binding of the protein

  8. Study with one global crab cavity at IR4 for LHC Upgrade

    CERN Document Server

    Barranco, J; Morita, A; Ralph Assmann, R; Sun, Y; Tomás, R; Weiler, T; Zimmermann, F; CERN. Geneva. BE Department

    2009-01-01

    In this note, we discuss the possible installation and impact on the beam of a single global crab cavity (CC) for both nominal LHC optics and one upgrade LHC optics (Lowbetamax). We also summarize the results on dynamic aperture tracking, luminosity, expected closed orbits, preliminary studies on collimation cleaning efficiency, and the emittance growth due to crab cavity ramping and other sources.

  9. Continuous wave room temperature external ring cavity quantum cascade laser

    Energy Technology Data Exchange (ETDEWEB)

    Revin, D. G., E-mail: d.revin@sheffield.ac.uk; Hemingway, M.; Vaitiekus, D.; Cockburn, J. W. [Physics and Astronomy Department, The University of Sheffield, S3 7RH Sheffield (United Kingdom); Hempler, N.; Maker, G. T.; Malcolm, G. P. A. [M Squared Lasers Ltd., G20 0SP Glasgow (United Kingdom)

    2015-06-29

    An external ring cavity quantum cascade laser operating at ∼5.2 μm wavelength in a continuous-wave regime at the temperature of 15 °C is demonstrated. Out-coupled continuous-wave optical powers of up to 23 mW are observed for light of one propagation direction with an estimated total intra-cavity optical power flux in excess of 340 mW. The uni-directional regime characterized by the intensity ratio of more than 60 for the light propagating in the opposite directions was achieved. A single emission peak wavelength tuning range of 90 cm{sup −1} is realized by the incorporation of a diffraction grating into the cavity.

  10. Continuous wave room temperature external ring cavity quantum cascade laser

    International Nuclear Information System (INIS)

    Revin, D. G.; Hemingway, M.; Vaitiekus, D.; Cockburn, J. W.; Hempler, N.; Maker, G. T.; Malcolm, G. P. A.

    2015-01-01

    An external ring cavity quantum cascade laser operating at ∼5.2 μm wavelength in a continuous-wave regime at the temperature of 15 °C is demonstrated. Out-coupled continuous-wave optical powers of up to 23 mW are observed for light of one propagation direction with an estimated total intra-cavity optical power flux in excess of 340 mW. The uni-directional regime characterized by the intensity ratio of more than 60 for the light propagating in the opposite directions was achieved. A single emission peak wavelength tuning range of 90 cm −1 is realized by the incorporation of a diffraction grating into the cavity

  11. Cavity-enhanced surface-plasmon resonance sensing: Modeling and performance

    Czech Academy of Sciences Publication Activity Database

    Giorgini, A.; Avino, S.; Malara, P.; Zullo, R.; Gaglio, G.; Homola, Jiří; De Natale, P.

    2014-01-01

    Roč. 25, č. 1 (2014), 015205 ISSN 0957-0233 Institutional support: RVO:67985882 Keywords : optical resonators * optical sensors * cavity ring-down spectroscopy Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.433, year: 2014

  12. First results of cavity ring down signals from exhaled air

    Science.gov (United States)

    Revalde, G.; Grundšteins, K.; Alnis, J.; Skudra, A.

    2017-12-01

    In this paper we report first results from the developed cavity ring-down spectrometer for application in human breath analysis for the diagnostics of diabetes and later for early detection of lung cancer. Our cavity ring-down spectrometer works in UV region with pulsed Nd:YAG laser at 266 nm wavelength. First experiments allow us to determine acetone and benzene at the level bellow ppm. In our experiment, first results from breath samples from volunteers after doing different activities were collected and examined. Influence of the smoking on the breath signals also was examined.

  13. Crescent shaped Fabry-Perot fiber cavity for ultra-sensitive strain measurement

    Science.gov (United States)

    Liu, Ye; Wang, D. N.; Chen, W. P.

    2016-12-01

    Optical Fabry-Perot interferometer sensors based on inner air-cavity is featured with compact size, good robustness and high strain sensitivity, especially when an ultra-thin air-cavity is adopted. The typical shape of Fabry-Perot inner air-cavity with reflection mode of operation is elliptic, with minor axis along with and major axis perpendicular to the fiber length. The first reflection surface is diverging whereas the second one is converging. To increase the visibility of the output interference pattern, the length of major axis should be large for a given cavity length. However, the largest value of the major axis is limited by the optical fiber diameter. If the major axis length reaches the fiber diameter, the robustness of the Fabry-Perot cavity device would be decreased. Here we demonstrate an ultra-thin crescent shaped Fabry-Perot cavity for strain sensing with ultra-high sensitivity and low temperature cross-sensitivity. The crescent-shape cavity consists of two converging reflection surfaces, which provide the advantages of enhanced strain sensitivity when compared with elliptic or D-shaped FP cavity. The device is fabricated by fusion splicing an etched multimode fiber with a single mode fiber, and hence is simple in structure and economic in cost.

  14. Decoherence in semiconductor cavity QED systems due to phonon couplings

    DEFF Research Database (Denmark)

    Nielsen, Per Kær; Mørk, Jesper

    2014-01-01

    We investigate the effect of electron-phonon interactions on the coherence properties of single photons emitted from a semiconductor cavity QED (quantum electrodynamics) system, i.e., a quantum dot embedded in an optical cavity. The degree of indistinguishability, governing the quantum mechanical...

  15. Atom-membrane cooling and entanglement using cavity electromagnetically induced transparency

    DEFF Research Database (Denmark)

    Genes, Claudiu; Ritsch, Helmut; Drewsen, Michael

    2011-01-01

    We investigate a hybrid optomechanical system composed of a micromechanical oscillator as a movable membrane and an atomic three-level ensemble within an optical cavity. We show that a suitably tailored cavity field response via electromagnetically induced transparency (EIT) in the atomic medium...

  16. Initial Technology Assessment for the Large-Aperture UV-Optical-Infrared (LUVOIR) Mission Concept Study

    Science.gov (United States)

    Bolcar, Matthew R.; Feinberg, Lee; France, Kevin; Rauscher, Bernard J.; Redding, David; Schiminovich, David

    2016-01-01

    The NASA Astrophysics Division's 30-Year Roadmap prioritized a future large-aperture space telescope operating in the ultra-violet/optical/infrared wavelength regime. The Association of Universities for Research in Astronomy envisioned a similar observatory, the High Definition Space Telescope. And a multi-institution group also studied the Advanced Technology Large Aperture Space Telescope. In all three cases, a broad science case is outlined, combining general astrophysics with the search for biosignatures via direct-imaging and spectroscopic characterization of habitable exoplanets. We present an initial technology assessment that enables such an observatory that is currently being studied for the 2020 Decadal Survey by the Large UV/Optical/Infrared (LUVOIR) surveyor Science and Technology Definition Team. We present here the technology prioritization for the 2016 technology cycle and define the required technology capabilities and current state-of-the-art performance. Current, planned, and recommended technology development efforts are also reported.

  17. UV Light Induces Dedoping of Polyaniline

    Directory of Open Access Journals (Sweden)

    Yuki Kaitsuka

    2016-01-01

    Full Text Available UV (Ultra-Violet light-driven change in optical absorption of polyaniline (PANI is reported. Irradiation of UV light to PANI/camphor sulfonic acid prepared by electrochemical polymerization allows dedoping of the PANI. Especially, UV light irradiation in the presence of a radical trap agent effectively reduces (dedoping the PANI. The result in this study is quite simple; however, this may be a first report for light-induced dedoping (color change of a conductive polymer.

  18. Application of low-coherence optical fiber Doppler anemometry to fluid-flow measurement: optical system considerations

    Science.gov (United States)

    Boyle, William J. O.; Grattan, Kenneth T. V.; Palmer, Andrew W.; Meggitt, B. T.

    1991-08-01

    A fiber optic Doppler anemometric (FODA) sensor using an optical delay cavity technique and having the advantage of detecting velocity rather than simple speed is outlined. In this sensor the delay in a sensor cavity formed from light back-reflected from a fiber tip (Fresnel reflection) and light back-reflected from particles flowing in a fluid is balanced by the optical delay when light from this sensor cavity passes through a reference cavity formed by a combination of the zero and first diffraction orders produced by a Bragg cell inserted into the optical arrangement. The performance of an experimental sensor based on this scheme is investigated, and velocity measurements using the Doppler shift data from moving objects are presented. The sensitivity of the scheme is discussed, with reference to the other techniques of fluid flow measurement.

  19. An ultra-long cavity passively mode-locked fiber laser based on nonlinear polarization rotation in a semiconductor optical amplifier

    International Nuclear Information System (INIS)

    Liu, Tonghui; Jia, Dongfang; Yang, Jingwen; Chen, Jiong; Wang, Zhaoying; Yang, Tianxin

    2013-01-01

    In this paper we investigate an ultra-long cavity passively mode-locked fiber laser based on a semiconductor optical amplifier (SOA). Experimental results are presented which indicate that stable mode-locked pulses can be obtained by combining nonlinear polarization rotation (NPR) in the SOA with a polarization controller. By adding a 4 km single mode fiber into the ring cavity, a stable fundamental-order mode-locked pulse train with a repetition rate of 50.72 kHz is generated through the NPR effect in the SOA. The central wavelength, 3 dB bandwidth and single pulse energy of the output pulse are 1543.95 nm, 1.506 nm and 33.12 nJ, respectively. Harmonic mode-locked pulses are also observed in experiments when the parameters are chosen properly. (paper)

  20. Alignment of Duke free electron laser storage ring and optical beam delivery system

    International Nuclear Information System (INIS)

    Emamian, M.; Hower, N.

    1999-01-01

    Duke Free Electron Laser Laboratory (DFELL) hosts a 1.1 GeV electron beam storage ring facility which is capable of generating beams in the range of nearly monochromatic gamma rays to high peak power infra red (IR) laser. In this report specifications and procedures for alignment of OK-4 /Duke storage ring FEL wiggler and optical cavity mirrors will be discussed. The OK-4 FEL lasing has demonstrated a series of world record in the last few years. In August of this year the OK-4 FEL successfully commissioned to laser at 193.7 nm. Also in this article, alignment of the γ-ray and UV optical beam delivery system that is currently in progress will be described. (authors)

  1. Optical, UV, and EUV Oscillations of SS Cygni in Outburst

    Science.gov (United States)

    Mauche, Christopher W.

    2004-07-01

    I provide a review of observations in the optical, UV (HST), and EUV (EUVE and Chandra LETG) of the rapid periodic oscillations of nonmagnetic, disk-accreting, high mass-accretion rate cataclysmic variables (CVs), with particular emphasis on the dwarf nova SS Cyg in outburst. In addition, I drawn attention to a correlation, valid over nearly six orders of magnitude in frequency, between the frequencies of the quasi-periodic oscillations (QPOs) of white dwarf, neutron star, and black hole binaries. This correlation identifies the high frequency quasi-coherent oscillations (so-called ``dwarf nova oscillations'') of CVs with the kilohertz QPOs of low mass X-ray binaries (LMXBs), and the low frequency and low coherence QPOs of CVs with the horizontal branch oscillations (or the broad noise component identified as such) of LMXBs. Assuming that the same mechanisms produce the QPOs of white dwarf, neutron star, and black hole binaries, this correlation has important implications for QPO models.

  2. Cavity Cooling of Nanoparticles: Towards Matter-Wave experiments

    Science.gov (United States)

    Millen, James; Kuhn, Stefan; Arndt, Markus

    2016-05-01

    Levitated systems are a fascinating addition to the world of optically-controlled mechanical resonators. It is predicted that nanoparticles can be cooled to their c.o.m. ground state via the interaction with an optical cavity. By freeing the oscillator from clamping forces dissipation and decoherence is greatly reduced, leading to the potential to produce long-lived, macroscopically spread, mechanical quantum states, allowing tests of collapse models and any mass limit of quantum physics. Reaching the low pressures required to cavity-cool to the ground state has proved challenging. Our approach is to cavity cool a beam of nanoparticles in high vacuum. We can cool the c.o.m. motion of nanospheres a few hundred nanometers in size. Looking forward, we will utilize novel microcavities to enhance optomechanical cooling, preparing particles in a coherent beam ideally suited to ultra-high mass interferometry at 107 a.m.u.

  3. Modes and Mode Volumes for Leaky Optical Cavities and Plasmonic Nanoresonators

    DEFF Research Database (Denmark)

    Hughes, Stephen; Kristensen, Philip Trøst

    2013-01-01

    Electromagnetic cavity modes in photonic and plasmonic resonators offer rich and attractive regimes for tailoring the properties of light–matter interactions, yet there is a disturbing lack of a precise definition for what constitutes a cavity mode, and as a result their mathematical properties r...... methods for quasinormal modes of both photonic and plasmonic resonators and the concept of a generalized effective mode volume, and we illustrate the theory with several representative cavity structures from the fields of photonic crystals and nanoplasmonics....

  4. Graphene photonics for resonator-enhanced electro-optic devices and all-optical interactions

    Science.gov (United States)

    Englund, Dirk R.; Gan, Xuetao

    2017-03-21

    Techniques for coupling light into graphene using a planar photonic crystal having a resonant cavity characterized by a mode volume and a quality factor and at least one graphene layer positioned in proximity to the planar photonic crystal to at least partially overlap with an evanescent field of the resonant cavity. At least one mode of the resonant cavity can couple into the graphene layer via evanescent coupling. The optical properties of the graphene layer can be controlled, and characteristics of the graphene-cavity system can be detected. Coupling light into graphene can include electro-optic modulation of light, photodetection, saturable absorption, bistability, and autocorrelation.

  5. UV-induced carbon monoxide emission from sand and living vegetation

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2012-01-01

    The global burden of carbon monoxide, CO, is rather uncertain. In this paper we address the potential of UV-induced CO emission by terrestrial surfaces. Real-time measurements of [CO] were made with a cavity enhanced laser connected in closed loop to either an ecosystem chamber or a leaf scale...... chamber. Sand and leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation and the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature, indicating an abiotic process. The emission of CO...... in response to the UV-component of natural solar radiation was also evident at the ecosystem scale. When scaled to the global level, the UV-induced emission of CO by the major types of terrestrial surfaces, living leaves and soil (here represented by sand), amounts up to 28 Tg yr−1. This source has...

  6. Optical coherence elastography for evaluating customized riboflavin/UV-A corneal collagen crosslinking

    Science.gov (United States)

    Singh, Manmohan; Li, Jiasong; Vantipalli, Srilatha; Han, Zhaolong; Larin, Kirill V.; Twa, Michael D.

    2017-09-01

    UV-induced collagen cross-linking is a promising treatment for keratoconus that stiffens corneal tissue and prevents further degeneration. Since keratoconus is generally localized, the efficacy of collagen cross-linking (CXL) treatments could be improved by stiffening only the weakened parts of the cornea. Here, we demonstrate that optical coherence elastography (OCE) can spatially resolve transverse variations in corneal stiffness. A short duration (≤1 ms) focused air-pulse induced low amplitude (≤10 μm) deformations in the samples that were detected using a phase-stabilized optical coherence tomography system. A two-dimensional map of material stiffness was generated by measuring the damped natural frequency (DNF) of the air-pulse induced response at various transverse locations of a heterogeneous phantom mimicking a customized CXL treatment. After validation on the phantoms, similar OCE measurements were made on spatially selective CXL-treated in situ rabbit corneas. The results showed that this technique was able to clearly distinguish the untreated and CXL-treated regions of the cornea, where CXL increased the DNF of the cornea by ˜51%. Due to the noncontact nature and minimal excitation force, this technique may be valuable for in vivo assessments of corneal biomechanical properties.

  7. Optical properties of organic-silicon photonic crystal nanoslot cavity light source

    Directory of Open Access Journals (Sweden)

    Ming-Jay Yang

    2017-03-01

    Full Text Available We theoretically study a dielectric photonic crystal nanoslot cavity immersed in an organic fluid containing near-infrared dyes by means of a full rate equation model including the complete cavity QED effects. Based on the modeling results, we numerically design an organic-silicon cavity light source in which its mode volume, quality factor, and far-field emission pattern are optimized for energy-efficient, high-speed applications. Dye quantum efficiency improved by two orders of magnitude and 3dB modulation bandwidth of a few hundred GHz can be obtained.

  8. Effect of UV irradiations on the structural and optical features of porous silicon: application in silicon solar cells

    International Nuclear Information System (INIS)

    Aouida, S.; Saadoun, M.; Boujmil, M.F.; Ben Rabha, M.; Bessaies, B.

    2004-01-01

    The aim of this paper is to investigate the structural and optical stability of porous silicon layers (PSLs) planned to be used in silicon solar cells technology. The PSLs were prepared by a HNO 3 /HF vapor etching (VE) based method. Fourier transform infrared (FT-IR) spectroscopy shows that fresh VE-based PSLs contain N-H and Si-F bonds related to a ammonium hexafluorosilicate (NH 4 ) 2 SiF 6 minor phase, and conventional Si-H x and Si-O x bonds. Free air exposures of PSLs without and with UV irradiation lead to oxidation or photo-oxidation of the porous layer, respectively. FT-IR characterisation of the PSLs shows that UV irradiations modify the transformation kinetics replacing instable Si-H x by Si-O x or Si-O-H bonds. When fresh PSLs undergo free air oxidation within 7 days, the surface reflectivity decreases from 10 to about 8%, while it drops to about 4% when a 10 min free air UV irradiation is applied. Long periods of free air oxidation do not ensure the reflectivity to be stable, whereas it becomes stable after only 10 min of UV irradiation. This behaviour was explained taking into account the kinetic differences between oxidation with and without UV irradiation. Fresh VE-based PSLs were found to improve efficiently the photovoltaic (PV) characteristics of crystalline silicon solar cells. The passivating action of VE-based PSLs was discussed. An improvement of the PV performances was observed solely for stable oxidized porous silicon (PS) structures obtained from UV irradiations

  9. Cavity-induced artificial gauge field in a Bose-Hubbard ladder

    Science.gov (United States)

    Halati, Catalin-Mihai; Sheikhan, Ameneh; Kollath, Corinna

    2017-12-01

    We consider theoretically ultracold interacting bosonic atoms confined to quasi-one-dimensional ladder structures formed by optical lattices and coupled to the field of an optical cavity. The atoms can collect a spatial phase imprint during a cavity-assisted tunneling along a rung via Raman transitions employing a cavity mode and a transverse running wave pump beam. By adiabatic elimination of the cavity field we obtain an effective Hamiltonian for the bosonic atoms, with a self-consistency condition. Using the numerical density-matrix renormalization-group method, we obtain a rich steady-state diagram of self-organized steady states. Transitions between superfluid to Mott-insulating states occur, on top of which we can have Meissner, vortex liquid, and vortex lattice phases. Also a state that explicitly breaks the symmetry between the two legs of the ladder, namely, the biased-ladder phase, is dynamically stabilized. We investigate the influence that a trapping potential has on the stability of the self-organized phases.

  10. Transient dynamics in cavity electromagnetically induced transparency with ion Coulomb crystals

    Science.gov (United States)

    Albert, Magnus; Dantan, Aurélien; Drewsen, Michael

    2018-03-01

    We experimentally investigate the transient dynamics of an optical cavity field interacting with large ion Coulomb crystals in a situation of electromagnetically induced transparency (EIT). EIT is achieved by injecting a probe field at the single photon level and a more intense control field with opposite circular polarization into the same mode of an optical cavity to couple Zeeman substates of a metastable level in ? ions. The EIT interaction dynamics are investigated both in the frequency-domain - by measuring the probe field steady state reflectivity spectrum - and in the time-domain - by measuring the progressive buildup of transparency. The experimental results are observed to be in excellent agreement with theoretical predictions taking into account the inhomogeneity of the control field in the interaction volume, and confirm the high degree of control on light-matter interaction that can be achieved with ion Coulomb crystals in optical cavities.

  11. Comparison Of Optical, UV, X-ray, And Gamma-ray Variations Of Selected Blazars In 2011

    Science.gov (United States)

    Consiglio, Santina; Marscher, A. P.; Jorstad, S. G.; Walker, G.

    2012-01-01

    We present multi-wavelength observations of several gamma-ray bright blazars. We combine optical data obtained at Maria Mitchell Observatory on Nantucket Island with space- and ground-based observations carried out with a variety of instruments. These include a number of other optical telescopes, the Fermi Gamma-ray Space Telescope at photon energies of 0.1-200 GeV, the Rossi X-Ray Timing Explorer at 2.4-10 keV, and the Swift satellite at 0.3-10 keV plus optical and UV wavelengths. Three of the observed blazars proved to be particularly active - BL Lac, 3C 279, and PKS 1510-089. BL Lac was of special interest, varying greatly in optical brightness from night to night. In addition, as reported by the VERITAS group, it exhibited a remarkable, short-lived flare at TeV gamma-ray energies on one of the nights. We cross-correlate the variations in the different wavebands in an effort to guide theoretical interpretations of the optical and high-energy emission from blazars. This project was supported by NSF/REU grant AST-0851892 and by the Nantucket Maria Mitchell Association. The research at Boston University was supported in part by NSF grants AST-0907893, and by NASA through Fermi grants NNX08AV65G and NNX11AQ03G.

  12. Cavity-enhanced surface-plasmon resonance sensing: modeling and performance

    International Nuclear Information System (INIS)

    Giorgini, A; Avino, S; Malara, P; Zullo, R; Gagliardi, G; Homola, J; De Natale, P

    2014-01-01

    We investigate the performance of a surface-plasmon-resonance refractive-index (RI) sensor based on an optical resonator. The resonator transforms RI changes of liquid samples, interacting with the surface plasmon excited by near-infrared light, into a variation of the intra-cavity optical loss. Cavity ring-down measurements are provided as a proof of concept of RI sensing on calibrated mixtures. A characterization of the overall sensor response and noise features as well as a discussion on possible improvements is carried out. A reproducibility analysis shows that a resolution of 10 −7 –10 −8  RIU is within reach over observation times of 1–30 s. The ultimate resolution is set only by intrinsic noise features of the cavity-based method, pointing to a potential limit below 10 −10  RIU/√Hz. (paper)

  13. Laboratory Measurements of Optical Properties of Micron Size Individual Dust Grains

    Science.gov (United States)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; Witherow, W. K.; Camata, R.; Gerakines, P.

    2003-01-01

    A laboratory program is being developed at NASA Marshall Space Flight Center for experimental determination of the optical and physical properties individual dust grains in simulated astrophysical environments. The experimental setup is based on an electrodynamic balance that permits levitation of single 0.1 - 10 micron radii dust grains in a cavity evacuated to pressures of approx. 10(exp -6) torr. The experimental apparatus is equipped with observational ports for measurements in the UV, visible, and infrared spectral regions. A cryogenic facility for cooling the particles to temperature of approx. 10-50K is being installed. The current and the planned measurements include: dust charging processes, photoelectric emissions and yields with UV irradiation, radiation pressure measurements, infrared absorption and scattering properties, and condensation processes, involving the analogs of cosmic dust grains. Selected results based on photoemissions, radiation pressure, and other laboratory measurements will be presented.

  14. Reflectivity and transmissivity of a cavity coupled to a nanoparticle

    Science.gov (United States)

    Khan, M. A.; Farooq, K.; Hou, S. C.; Niaz, Shanawer; Yi, X. X.

    2014-07-01

    Any dielectric nanoparticle moving inside an optical cavity generates an optomechanical interaction. In this paper, we theoretically analyze the light scattering of an optomechanical cavity which strongly interacts with a dielectric nanoparticle. The cavity is driven by an external laser field. This interaction gives rise to different dynamics that can be used to cool, trap and levitate nanoparticle. We analytically calculate reflection and transmission rate of the cavity field, and study the time evolution of the intracavity field, momentum and position of the nanoparticle. We find the nanoparticle occupies a discrete position inside the cavity. This effect can be exploited to separate nanoparticle and couplings between classical particles and quantized fields.

  15. Fast Excitation and Photon Emission of a Single-Atom-Cavity System

    International Nuclear Information System (INIS)

    Bochmann, J.; Muecke, M.; Langfahl-Klabes, G.; Erbel, C.; Weber, B.; Specht, H. P.; Moehring, D. L.; Rempe, G.

    2008-01-01

    We report on the fast excitation of a single atom coupled to an optical cavity using laser pulses that are much shorter than all other relevant processes. The cavity frequency constitutes a control parameter that allows the creation of single photons in a superposition of two tunable frequencies. Each photon emitted from the cavity thus exhibits a pronounced amplitude modulation determined by the oscillatory energy exchange between the atom and the cavity. Our technique constitutes a versatile tool for future quantum networking experiments

  16. Effect of UV laser irradiation on tissue

    International Nuclear Information System (INIS)

    Nakayama, Takeyoshi; Kubo, Uichi

    1992-01-01

    Laser-tissue interactions have been investigated through Electron Probe Micro Analysis (EPMA), UV-visible optical absorption and Fourier Transform Infrared Spectroscopy (FTIR). Three excimer lasers, ArF, KrF and XeCl, were used to irradiate tissue; cow thighbone and gelatin thin film. Features of UV laser irradiation are described. (author)

  17. Cavity QED with single trapped Ca+-ions

    International Nuclear Information System (INIS)

    Mundt, A.B.

    2003-02-01

    This thesis reports on the design and setup of a vacuum apparatus allowing the investigation of cavity QED effects with single trapped 40 Ca + ions. The weak coupling of ion and cavity in the 'bad cavity limit' may serve to inter--convert stationary and flying qubits. The ion is confined in a miniaturized Paul trap and cooled via the Doppler effect to the Lamb--Dicke regime. The extent of the atomic wave function is less than 30 nm. The ion is enclosed by a high finesse optical cavity. The technically--involved apparatus allows movement of the trap relative to the cavity and the trapped ion can be placed at any position in the standing wave. By means of a transfer lock the cavity can be resonantly stabilized with the S 1/2 ↔ D 5/2 quadrupole transition at 729 nm (suitable as a qubit) without light at that wavelength being present in the cavity. The coupling of the cavity field to the S 1/2 ↔ D 5/2 quadrupole transition is investigated with various techniques in order to determine the spatial dependence as well as the temporal dynamics. The orthogonal coupling of carrier and first--order sideband transitions at field nodes and antinodes is explored. The coherent interaction of the ion and the cavity field is confirmed by exciting Rabi oscillations with short resonant pulses injected into the cavity. Finally, first experimental steps towards the observation of cavity enhanced spontaneous emission have been taken. (author)

  18. Intra–cavity flat–top beam generation

    CSIR Research Space (South Africa)

    Litvin, IA

    2009-08-01

    Full Text Available In this paper the authors present the analytical and numerical analyses of two new resonator systems for generating flat–top–like beams. Both approaches lead to closed form expressions for the required cavity optics, but differ substantially...

  19. Novel Ion Trap Design for Strong Ion-Cavity Coupling

    Directory of Open Access Journals (Sweden)

    Alejandro Márquez Seco

    2016-04-01

    Full Text Available We present a novel ion trap design which facilitates the integration of an optical fiber cavity into the trap structure. The optical fibers are confined inside hollow electrodes in such a way that tight shielding and free movement of the fibers are simultaneously achievable. The latter enables in situ optimization of the overlap between the trapped ions and the cavity field. Through numerical simulations, we systematically analyze the effects of the electrode geometry on the trapping characteristics such as trap depths, secular frequencies and the optical access angle. Additionally, we simulate the effects of the presence of the fibers and confirm the robustness of the trapping potential. Based on these simulations and other technical considerations, we devise a practical trap configuration that isviable to achieve strong coupling of a single ion.

  20. Self-assembly of nitrogen-doped carbon nanoparticles: a new ratiometric UV-vis optical sensor for the highly sensitive and selective detection of Hg(2+) in aqueous solution.

    Science.gov (United States)

    Ruan, Yudi; Wu, Lie; Jiang, Xiue

    2016-05-23

    Water-soluble nitrogen-doped carbon nanoparticles (N-CNPs) prepared by the one-step hydrothermal treatment of uric acid were found to show ratiometric changes in their UV-vis spectra due to Hg(2+)-mediated self-assembly. For the first time, such a property was developed into a UV-vis optical sensor for detecting Hg(2+) in aqueous solutions with high sensitively and selectively (detection limit = 1.4 nM). More importantly, this novel sensor exhibits a higher linear sensitivity over a wider concentration range compared with the fluorescence sensor based on the same N-CNPs. This work opens an exciting new avenue to explore the use of carbon nanoparticles in constructing UV-vis optical sensors for the detection of metal ions and the use of carbon nanoparticles as a new building block to self-assemble into superlattices.

  1. Simple method for measuring reflectance of optical coatings

    International Nuclear Information System (INIS)

    Wen Gui Wang; Yi Sheng Chen

    1995-01-01

    The quality of optical coatings has an important effect on the performance of optical instrument. The last few years, the requirements for super low loss dielectric mirror coatings used in low gain laser systems such as free electron laser and the ring laser etc., have given an impetus to the development of the technology of precise reflectance measurement of optical coatings. A reliable and workable technique is to measure the light intensity decay time of optical resonant cavity. This paper describes a measuring method which is dependent on direct measurement of the light intensity decay time of a resonant cavity comprised of low loss optical components. According to the evolution of a luminous flux stored inside the cavity, this method guarantees not only a quick and precise reflectance measurements of low loss highly reflecting mirror coatings but also transmittance measurements of low loss antireflection coatings and is especially effective with super los loss highly reflecting mirror. From the round-trip path length of the cavity and the speed of light, the light intensity exponential decay time of an optical cavity is easy to obtain and the cavity losses can be deduced. An optical reflectance of low loss highly mirror coatings and antireflection coatings is precisely measured as well. This is highly significant for the discrimination of the coating surface characteristics, the improvement of the performance of optical instrument and the development of high technology

  2. Automated Surface Classification of SRF Cavities for the Investigation of the Influence of Surface Properties onto the Operational Performance

    Energy Technology Data Exchange (ETDEWEB)

    Wenskat, Marc

    2015-07-15

    Superconducting niobium radio-frequency cavities are fundamental for the European XFEL and the International Linear Collider. To use the operational advantages of superconducting cavities, the inner surface has to fulfill quite demanding requirements. The surface roughness and cleanliness improved over the last decades and with them, the achieved maximal accelerating field. Still, limitations of the maximal achieved accelerating field are observed, which are not explained by localized geometrical defects or impurities. The scope of this thesis is a better understanding of these limitations in defect free cavities based on global, rather than local, surface properties. For this goal, more than 30 cavities underwent subsequent surface treatments, cold RF tests and optical inspections within the ILC-HiGrade research program and the XFEL cavity production. An algorithm was developed which allows an automated surface characterization based on an optical inspection robot. This algorithm delivers a set of optical surface properties, which describes the inner cavity surface. These optical surface properties deliver a framework for a quality assurance of the fabrication procedures. Furthermore, they shows promising results for a better understanding of the observed limitations in defect free cavities.

  3. Automated Surface Classification of SRF Cavities for the Investigation of the Influence of Surface Properties onto the Operational Performance

    International Nuclear Information System (INIS)

    Wenskat, Marc

    2015-07-01

    Superconducting niobium radio-frequency cavities are fundamental for the European XFEL and the International Linear Collider. To use the operational advantages of superconducting cavities, the inner surface has to fulfill quite demanding requirements. The surface roughness and cleanliness improved over the last decades and with them, the achieved maximal accelerating field. Still, limitations of the maximal achieved accelerating field are observed, which are not explained by localized geometrical defects or impurities. The scope of this thesis is a better understanding of these limitations in defect free cavities based on global, rather than local, surface properties. For this goal, more than 30 cavities underwent subsequent surface treatments, cold RF tests and optical inspections within the ILC-HiGrade research program and the XFEL cavity production. An algorithm was developed which allows an automated surface characterization based on an optical inspection robot. This algorithm delivers a set of optical surface properties, which describes the inner cavity surface. These optical surface properties deliver a framework for a quality assurance of the fabrication procedures. Furthermore, they shows promising results for a better understanding of the observed limitations in defect free cavities.

  4. Dual resonance approach to optical signal processing beyond the carrier relaxation rate

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Kristensen, Philip Trøst; Mørk, Jesper

    2014-01-01

    We propose using two optical cavities in a differential control scheme to increase the bandwidth of cavity-based semiconductor optical signal processing devices beyond the limit given by the slowest carrier relaxation rate of the medium.......We propose using two optical cavities in a differential control scheme to increase the bandwidth of cavity-based semiconductor optical signal processing devices beyond the limit given by the slowest carrier relaxation rate of the medium....

  5. Application of the guided lock technique to Advanced Virgo's high-finesse cavities using reduced actuation

    Science.gov (United States)

    Bersanetti, Diego

    2018-02-01

    The recent upgrades of the Advanced Virgo experiment required an update of the locking strategy for the long, high-finesse arm cavities of the detector. In this work we will present a full description of the requirements and the constraints of such system in relation to the lock acquisition of the cavities; the focus of this work is the strategy used to accomplish this goal, which is the adaptation and use of the guided lock technique, which dynamically slows down a suspended optical cavity in order to make the lock possible. This work describes the first application of such locking technique to 3km long optical cavities, which are affected by stringent constraints as the low force available on the actuators, the high finesse and the maximum sustainable speed of the cavities, which is quite low due to a number of technical reasons that will be explained. A full set of optical time domain simulations has been developed in order to study the feasibility and the performance of this algorithm and will be throughout discussed, while finally the application on the real Advanced Virgo's arm cavities will be reported.

  6. Correlation between short-range order, optical properties and UV-absorption ability in tellurate glasses; Poster M7

    Energy Technology Data Exchange (ETDEWEB)

    Burger, H; Tews, W; Vogel, W; Kozhukharov, V [Jena Univ. (Germany)

    1989-01-01

    Tellurate glasses, with as second components Al[sub 2]O[sub 3], PbO, PbF[sub 2], PbCl[sub 2], PbBr[sub 2], PbSO[sub 4], ZnO, B[sub 2]O[sub 3], P[sub 2]O[sub 5], Li[sub 2]O, Na[sub 2]O, K[sub 2]O, MgO and BaO as well as some glasses from ternary TeO[sub 2]-P[sub 2]O[sub 5]-RO systems (R is Pb, Ba and Zn ions), have been investigated. Transmittance spectra in UV and VIS region of some selected glasses have been measured. A correlation between optical properties and UV absorption edge of the transmittance have been done. Using p[sup 31]-NMR spectroscopy the structural changes on short-range level order are studied. A strong influence on the refraction and dispersion values as well as UV-absorption ability of the glasses is established. For p[sup 31] -NMR spectroscopy investigations of crystalline phosphotellurites and related phosphotellurite glasses the TeO[sub 2]-P[sub 2]O[sub 5B]aO ternary system have been chosen. (author).

  7. Cavity quantum electrodynamics with Anderson-localized modes

    DEFF Research Database (Denmark)

    Sapienza, Luca; Nielsen, Henri Thyrrestrup; Stobbe, Søren

    2010-01-01

    by a factor of 15 on resonance with the Anderson-localized mode, and 94% of the emitted single photons coupled to the mode. Disordered photonic media thus provide an efficient platform for quantum electrodynamics, offering an approach to inherently disorder-robust quantum information devices.......A major challenge in quantum optics and quantum information technology is to enhance the interaction between single photons and single quantum emitters. This requires highly engineered optical cavities that are inherently sensitive to fabrication imperfections. We have demonstrated a fundamentally...... different approach in which disorder is used as a resource rather than a nuisance. We generated strongly confined Anderson-localized cavity modes by deliberately adding disorder to photonic crystal waveguides. The emission rate of a semiconductor quantum dot embedded in the waveguide was enhanced...

  8. Intertwined and vestigial order with ultracold atoms in multiple cavity modes

    Science.gov (United States)

    Gopalakrishnan, Sarang; Shchadilova, Yulia E.; Demler, Eugene

    2017-12-01

    Atoms in transversely pumped optical cavities "self-organize" by forming a density wave and emitting superradiantly into the cavity mode(s). For a single-mode cavity, the properties of this self-organization transition are well characterized both theoretically and experimentally. Here, we explore the self-organization of a Bose-Einstein condensate in the presence of two cavity modes—a system that recently was realized experimentally [Léonard et al., Nature (London) 543, 87 (2017), 10.1038/nature21067]. We argue that this system can exhibit a "vestigially ordered" phase in which neither cavity mode exhibits superradiance but the cavity modes are mutually phase locked by the atoms. We argue that this vestigially ordered phase should generically be present in multimode cavity geometries.

  9. A diode-pumped Tm:YAG laser with an elliptical cavity mode

    International Nuclear Information System (INIS)

    Lipnicki, E.; Dawes, J.M.; Browne, P.G.

    2000-01-01

    Full text: A cavity consisting of cylindrical mirrors/lenses resulting in an elliptical cavity mode is being applied to a 3-level laser; Tm:YAG which lases near 2μm. This arrangement allows the use of simple pump beam optics but also ensures efficient mode matching with good output beam quality. This cavity has been designed and modelled with experiments under way to explore the advantages of this laser design

  10. Real-time multiplexed digital cavity-enhanced spectroscopy

    International Nuclear Information System (INIS)

    Boyson, Toby K.; Dagdigian, Paul J.; Pavey, Karl D.; Fitzgerald, Nicholas J.; Spence, Thomas G.; Moore, David S.; Harb, Charles C.

    2015-01-01

    Cavity-enhanced spectroscopy is a sensitive optical absorption technique but one where the practical applications have been limited to studying small wavelength ranges. In addition, this Letter shows that wideband operation can be achieved by combining techniques usually reserved for the communications community with that of cavity-enhanced spectroscopy, producing a multiplexed real-time cavity-enhanced spectrometer. We use multiple collinear laser sources operating asynchronously and simultaneously while being detected on a single photodetector. This is synonymous with radio frequency (RF) cellular systems in which signals are detected on a single antenna but decoded uniquely. Here, we demonstrate results with spectra of methyl salicylate and show parts-per-billion per root hertz sensitivity measured in real-time

  11. Fabrication of high-aspect-ratio microstructures using dielectrophoresis-electrocapillary force-driven UV-imprinting

    International Nuclear Information System (INIS)

    Li, Xiangming; Shao, Jinyou; Tian, Hongmiao; Ding, Yucheng; Li, Xiangmeng

    2011-01-01

    We propose a novel method for fabricating high-aspect-ratio micro-/nano-structures by dielectrophoresis-electrocapillary force (DEP-ECF)-driven UV-imprinting. The force of DEP-ECF, acting on an air–liquid interface and an air–liquid–solid three-phase contact line, is generated by applying voltage between an electrically conductive mold and a substrate, and tends to pull the dielectric liquid (a UV-curable pre-polymer) into the mold micro-cavities. The existence of DEP-ECF is explained theoretically and demonstrated experimentally by the electrically induced reduction of the contact angle. Furthermore, DEP-ECF is proven to play a critical role in forcing the polymer to fill into the mold cavities by the real-time observation of the dynamic filling process. Using the DEP-ECF-driven UV-imprinting process, high-aspect-ratio polymer micro-/nano-structures (more than 10:1) are fabricated with high consistency. This patterning method can overcome the drawbacks of the mechanically induced mold deformation and position shift in conventional imprinting lithography and maximize the pattern uniformity which is usually poor in capillary force lithography

  12. Towards a versatile active wavelength converter for all-optical networks based on quasi-phase matched intra-cavity difference-frequency generation.

    Science.gov (United States)

    Torregrosa, Adrián J; Maestre, Haroldo; Capmany, Juan

    2013-11-18

    The availability of reconfigurable all-optical wavelength converters for an efficient and flexible use of optical resources in WDM (wavelength division multiplexing) networks is still lacking at present. We propose and report preliminary results on a versatile active technique for multiple and tunable wavelength conversions in the 1500-1700 nm spectral region. The technique is based on combining broadband quasi-phase matched intra-cavity parametric single-pass difference-frequency generation close to degeneracy in a diode-pumped tunable laser. A periodically poled stoichiometric lithium tantalate crystal is used as the nonlinear medium, with a parametric pump wave generated in a continuous-wave self-injection locked Cr3+:LiCAF tunable laser operating at around 800 nm.

  13. Review of cavity optomechanical cooling

    International Nuclear Information System (INIS)

    Liu Yong-Chun; Hu Yu-Wen; Xiao Yun-Feng; Wong Chee Wei

    2013-01-01

    Quantum manipulation of macroscopic mechanical systems is of great interest in both fundamental physics and applications ranging from high-precision metrology to quantum information processing. For these purposes, a crucial step is to cool the mechanical system to its quantum ground state. In this review, we focus on the cavity optomechanical cooling, which exploits the cavity enhanced interaction between optical field and mechanical motion to reduce the thermal noise. Recent remarkable theoretical and experimental efforts in this field have taken a major step forward in preparing the motional quantum ground state of mesoscopic mechanical systems. This review first describes the quantum theory of cavity optomechanical cooling, including quantum noise approach and covariance approach; then, the up-to-date experimental progresses are introduced. Finally, new cooling approaches are discussed along the directions of cooling in the strong coupling regime and cooling beyond the resolved sideband limit. (topical review - quantum information)

  14. Study on the structure of bridge surface of the micro Fabry-Perot cavity tunable filter

    International Nuclear Information System (INIS)

    Meng Qinghua; Luo Huan; Bao Shiwei; Zhou Yifan; Chen Sihai

    2011-01-01

    Micro Fabry-Perot cavity tunable filters are widely applied in the area of Pushbroom Hyperspectral imaging, DWDM optical communication system and self-adaptive optics. With small volume, lower consumption and cost, the Micro Fabry-Perot cavity tunable filter can realize superior response speed, large spectral range, high definition and high reliability. By deposition metal membrane on silicon chip by MEMS technology, the micro Fabry-Perot cavity has been achieved, which is actuated by electrostatic force and can realize the function of an optical filter. In this paper, the micro-bridge structure of the micro Fabry-Perot cavity tunable filter has been studied. Finite element analysis software COMSOL Multiphysics has been adopted to design the structure of the micro-bridge of the micro filter. In order to simulate the working mechanism of the micro Fabry-Perot cavity and study the electrical and mechanical characteristics of the micro tunable filter,the static and dynamic characteriastics are analyzed, such as stress, displacement, transient response, etc. The corresponding parameters of the structure are considered as well by optimizition the filter's sustain structure.

  15. Cavity sideband cooling of trapped molecules

    NARCIS (Netherlands)

    Kowalewski, Markus; Morigi, Giovanna; Pinkse, Pepijn Willemszoon Harry; de Vivie-Riedle, Regina

    2011-01-01

    The efficiency of cavity sideband cooling of trapped molecules is theoretically investigated for the case in which the infrared transition between two rovibrational states is used as a cycling transition. The molecules are assumed to be trapped either by a radiofrequency or optical trapping

  16. Investigation of UV-LED Initiated Photopolymerisation of Bio-compatible HEMA

    OpenAIRE

    McDermott, Sharon

    2008-01-01

    Ultraviolet (UV) fluorescent lamps are widely used in photopolymerisation processes. However, there a number of disadvantages to these lamps, namely, their intensity varies over time and has to be constantly monitored. This thesis is concerned with the possibility of replacing these lamps with UV Light Emitting Diodes (UV-LEDs). A number of emission characteristics of both the fluorescent lamp and the UV-LEDs were measured and compared to ensure that the optical properties of the UV-LEDs were...

  17. A picogram- and nanometre-scale photonic-crystal optomechanical cavity.

    Science.gov (United States)

    Eichenfield, Matt; Camacho, Ryan; Chan, Jasper; Vahala, Kerry J; Painter, Oskar

    2009-05-28

    The dynamic back-action caused by electromagnetic forces (radiation pressure) in optical and microwave cavities is of growing interest. Back-action cooling, for example, is being pursued as a means of achieving the quantum ground state of macroscopic mechanical oscillators. Work in the optical domain has revolved around millimetre- or micrometre-scale structures using the radiation pressure force. By comparison, in microwave devices, low-loss superconducting structures have been used for gradient-force-mediated coupling to a nanomechanical oscillator of picogram mass. Here we describe measurements of an optical system consisting of a pair of specially patterned nanoscale beams in which optical and mechanical energies are simultaneously localized to a cubic-micron-scale volume, and for which large per-photon optical gradient forces are realized. The resulting scale of the per-photon force and the mass of the structure enable the exploration of cavity optomechanical regimes in which, for example, the mechanical rigidity of the structure is dominantly provided by the internal light field itself. In addition to precision measurement and sensitive force detection, nano-optomechanics may find application in reconfigurable and tunable photonic systems, light-based radio-frequency communication and the generation of giant optical nonlinearities for wavelength conversion and optical buffering.

  18. Entangling movable mirrors in a double cavity system

    DEFF Research Database (Denmark)

    Pinard, Michel; Dantan, Aurelien Romain; Vitali, David

    2005-01-01

    We propose a double-cavity set-up capable of generating a stationary entangled state of two movable mirrors at cryogenic temperatures. The scheme is based on the optimal transfer of squeezing of input optical fields to mechanical vibrational modes of the mirrors, realized by the radiation pressure...... of the intracavity light. We show that the presence of macroscopic entanglement can be demonstrated by an appropriate readout of the output light of the two cavities....

  19. Effect of Surface Plasmon Coupling to Optical Cavity Modes on the Field Enhancement and Spectral Response of Dimer-Based sensors

    KAUST Repository

    Alrasheed, Salma

    2017-09-05

    We present a theoretical approach to narrow the plasmon linewidth and enhance the near-field intensity at a plasmonic dimer gap (hot spot) through coupling the electric localized surface plasmon (LSP) resonance of a silver hemispherical dimer with the resonant modes of a Fabry-Perot (FP) cavity. The strong coupling is demonstrated by the large anticrossing in the reflection spectra and a Rabi splitting of 76 meV. Up to 2-fold enhancement increase can be achieved compared to that without using the cavity. Such high field enhancement has potential applications in optics, including sensors and high resolution imaging devices. In addition, the resonance splitting allows for greater flexibility in using the same array at different wavelengths. We then further propose a practical design to realize such a device and include dimers of different shapes and materials.

  20. Relaxation dynamics and coherent energy exchange in coupled vibration-cavity polaritons (Conference Presentation)

    Science.gov (United States)

    Simpkins, Blake S.; Fears, Kenan P.; Dressick, Walter J.; Dunkelberger, Adam D.; Spann, Bryan T.; Owrutsky, Jeffrey C.

    2016-09-01

    Coherent coupling between an optical transition and confined optical mode have been investigated for electronic-state transitions, however, only very recently have vibrational transitions been considered. Here, we demonstrate both static and dynamic results for vibrational bands strongly coupled to optical cavities. We experimentally and numerically describe strong coupling between a Fabry-Pérot cavity and carbonyl stretch ( 1730 cm 1) in poly-methylmethacrylate and provide evidence that the mixed-states are immune to inhomogeneous broadening. We investigate strong and weak coupling regimes through examination of cavities loaded with varying concentrations of a urethane monomer. Rabi splittings are in excellent agreement with an analytical description using no fitting parameters. Ultrafast pump-probe measurements reveal transient absorption signals over a frequency range well-separated from the vibrational band, as well as drastically modified relaxation rates. We speculate these modified kinetics are a consequence of the energy proximity between the vibration-cavity polariton modes and excited state transitions and that polaritons offer an alternative relaxation path for vibrational excitations. Varying the polariton energies by angle-tuning yields transient results consistent with this hypothesis. Furthermore, Rabi oscillations, or quantum beats, are observed at early times and we see evidence that these coherent vibration-cavity polariton excitations impact excited state population through cavity losses. Together, these results indicate that cavity coupling may be used to influence both excitation and relaxation rates of vibrations. Opening the field of polaritonic coupling to vibrational species promises to be a rich arena amenable to a wide variety of infrared-active bonds that can be studied in steady state and dynamically.

  1. Auger Processes Mediating the Nonresonant Optical Emission from a Semiconductor Quantum Dot Embedded Inside an Optical Cavity

    DEFF Research Database (Denmark)

    Settnes, Mikkel; Nielsen, Per Kær; Lund, Anders Mølbjerg

    2013-01-01

    perform microscopic calculations of the effect treating the wetting layer as a non-Markovian reservoir interacting with the coupled quantum dot-cavity system through Coulomb interactions. Experimentally, cavity feeding has been observed in the asymmetric detuning range of -10 to +45 meV. We show...

  2. Cavity optomechanics -- beyond the ground state

    Science.gov (United States)

    Meystre, Pierre

    2011-05-01

    The coupling of coherent optical systems to micromechanical devices, combined with breakthroughs in nanofabrication and in ultracold science, has opened up the exciting new field of cavity optomechanics. Cooling of the vibrational motion of a broad range on oscillating cantilevers and mirrors near their ground state has been demonstrated, and the ground state of at least one such system has now been reached. Cavity optomechanics offers much promise in addressing fundamental physics questions and in applications such as the detection of feeble forces and fields, or the coherent control of AMO systems and of nanoscale electromechanical devices. However, these applications require taking cavity optomechanics ``beyond the ground state.'' This includes the generation and detection of squeezed and other non-classical states, the transfer of squeezing between electromagnetic fields and motional quadratures, and the development of measurement schemes for the characterization of nanomechanical structures. The talk will present recent ``beyond ground state'' developments in cavity optomechanics. We will show how the magnetic coupling between a mechanical membrane and a BEC - or between a mechanical tuning fork and a nanoscale cantilever - permits to control and monitor the center-of-mass position of the mechanical system, and will comment on the measurement back-action on the membrane motion. We will also discuss of state transfer between optical and microwave fields and micromechanical devices. Work done in collaboration with Dan Goldbaum, Greg Phelps, Keith Schwab, Swati Singh, Steve Steinke, Mehmet Tesgin, and Mukund Vengallatore and supported by ARO, DARPA, NSF, and ONR.

  3. Cavity Control and Cooling of Nanoparticles in High Vacuum

    Science.gov (United States)

    Millen, James

    2016-05-01

    Levitated systems are a fascinating addition to the world of optically-controlled mechanical resonators. It is predicted that nanoparticles can be cooled to their c.o.m. ground state via the interaction with an optical cavity. By freeing the oscillator from clamping forces dissipation and decoherence is greatly reduced, leading to the potential to produce long-lived, macroscopically spread, mechanical quantum states, allowing tests of collapse models and any mass limit of quantum physics. Reaching the low pressures required to cavity-cool to the ground state has proved challenging. Our approach is to cavity cool a beam of nanoparticles in high vacuum. We can cool the c.o.m. motion of nanospheres, and control the rotation of nanorods, with the potential to produce cold, aligned nanostructures. Looking forward, we will utilize novel microcavities to enhance optomechanical cooling, preparing particles in a coherent beam ideally suited to ultra-high mass interferometry at 107 a.m.u.

  4. Remnants of semiclassical bistability in the few-photon regime of cavity QED.

    Science.gov (United States)

    Kerckhoff, Joseph; Armen, Michael A; Mabuchi, Hideo

    2011-11-21

    Broadband homodyne detection of the light transmitted by a Fabry-Perot cavity containing a strongly-coupled (133)Cs atom is used to probe the dynamic optical response in a regime where semiclassical theory predicts bistability but strong quantum corrections should apply. While quantum fluctuations destabilize true equilibrium bistability, our observations confirm the existence of metastable states with finite lifetimes and a hysteretic response is apparent when the optical drive is modulated on comparable timescales. Our experiment elucidates remnant semiclassical behavior in the attojoule (~10 photon) regime of single-atom cavity QED, of potential significance for ultra-low power photonic signal processing. © 2011 Optical Society of America

  5. Cavity plasmon polaritons in monolayer graphene

    International Nuclear Information System (INIS)

    Kotov, O.V.; Lozovik, Yu.E.

    2011-01-01

    Plasmon polaritons in a new system, a monolayer doped graphene embedded in optical microcavity, are studied here. The dispersion law for lower and upper cavity plasmon polaritons is obtained. Peculiarities of Rabi splitting for the system are analyzed; particularly, role of Dirac-like spinor (envelope) wave functions in graphene and corresponding angle factors are considered. Typical Rabi frequencies for maximal (acceptable for Dirac-like electron spectra) Fermi energy and frequencies of polaritons near polariton gap are estimated. The plasmon polaritons in considered system can be used for high-speed information transfer in the THz region. -- Highlights: → Plasmon polaritons in a monolayer doped graphene embedded in optical microcavity, are studied here. → The dispersion law for lower and upper cavity plasmon polaritons is obtained. → Peculiarities of Rabi splitting for the system are analyzed. → Role of Dirac-like wave functions in graphene and corresponding angle factors are considered. → Typical Rabi frequencies and frequencies of polaritons near polariton gap are estimated.

  6. Transmission-enabled fiber Fabry-Perot cavity based on a deeply etched slotted micromirror.

    Science.gov (United States)

    Othman, Muhammad A; Sabry, Yasser M; Sadek, Mohamed; Nassar, Ismail M; Khalil, Diaa A

    2018-06-01

    In this work, we report the analysis, fabrication, and characterization of an optical cavity built using a Bragg-coated fiber (BCF) mirror and a metal-coated microelectromechanical systems (MEMS) slotted micromirror, where the latter allows transmission output from the cavity. Theoretical modeling, using Fourier optics analysis for the cavity response based on tracing the propagation of light back and forth between the mirrors, is presented. Detailed simulation analysis is carried out for the spectral response of the cavity under different design conditions. MEMS chips of the slotted micromirror are fabricated using deep reactive ion etching of a silicon-on-insulator substrate with different device-etching depths of 150 μm and 80 μm with aluminum and gold metal coating, respectively. The cavity is characterized as an optical filter using a BCF with reflectivity that is larger than 95% in a 300 nm range across the E-band and the L-band. Versatile filter characteristics were obtained for different values of the MEMS micromirror slit width and cavity length. A free spectral range (FSR) of about 33 nm and a quality factor of about 196 were obtained for a 5.5 μm width aluminum slit, while an FSR of about 148 nm and a quality factor of about 148 were obtained for a 1.5 μm width gold slit. The presented structure opens the door for wide spectral response transmission-type MEMS filters.

  7. High aspect ratio silver grid transparent electrodes using UV embossing process

    Directory of Open Access Journals (Sweden)

    Dong Jin Kim

    2017-10-01

    Full Text Available This study presents a UV embossing process to fabricate high aspect ratio silver grid transparent electrodes on a polymer film. Transparent electrodes with a high optical transmittance (93 % and low sheet resistance (4.6 Ω/sq were fabricated without any high temperature or vacuum processes. The strong adhesion force between the UV resin and the silver ink enables the fabrication of silver microstructures with an aspect ratio higher than 3. The high aspect ratio results in a low sheet resistance while maintaining a high optical transmittance. Multi-layer transparent electrodes were fabricated by repeating the proposed UV process. Additionally, a large-area of 8-inch touch panel was fabricated with the proposed UV process. The proposed UV process is a relatively simple and low cost process making it suitable for large-area production as well as mass production.

  8. Quantum Control of a Spin Qubit Coupled to a Photonic Crystal Cavity

    Science.gov (United States)

    2012-12-01

    Cavities in Monocrystalline Diamond. Physical Review Letters 109, 033604 (2012). 14. Kroutvar, M. et al. Optically programmable electron spin...temperatures, varying the detuning of X− from the cavity. The dashed blue lines in panel a are fits to the reflectivity. The spectra are vertically

  9. In vivo microvascular imaging of human oral and nasal cavities using swept-source optical coherence tomography with a single forward/side viewing probe

    Science.gov (United States)

    Choi, Woo June; Wang, Ruikang K.

    2015-03-01

    We report three-dimensional (3D) imaging of microcirculation within human cavity tissues in vivo using a high-speed swept-source optical coherence tomography (SS-OCT) at 1.3 μm with a modified probe interface. Volumetric structural OCT images of the inner tissues of oral and nasal cavities are acquired with a field of view of 2 mm x 2 mm. Two types of disposable and detachable probe attachments are devised and applied to the port of the imaging probe of OCT system, enabling forward and side imaging scans for selective and easy access to specific cavity tissue sites. Blood perfusion is mapped with OCT-based microangiography from 3D structural OCT images, in which a novel vessel extraction algorithm is used to decouple dynamic light scattering signals, due to moving blood cells, from the background scattering signals due to static tissue elements. Characteristic tissue anatomy and microvessel architectures of various cavity tissue regions of a healthy human volunteer are identified with the 3D OCT images and the corresponding 3D vascular perfusion maps at a level approaching capillary resolution. The initial finding suggests that the proposed method may be engineered into a promising tool for evaluating and monitoring tissue microcirculation and its alteration within a wide-range of cavity tissues in the patients with various pathological conditions.

  10. Generation of single-frequency tunable green light in a coupled ring tapered diode laser cavity

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Petersen, Paul Michael

    2013-01-01

    in the broad wavelength range from 1049 nm to 1093 nm and the beam propagation factor is improved from M2 = 2.8 to below 1.1. The laser frequency is automatically locked to the cavity resonance frequency using optical feedback. Furthermore, we show that this adaptive external cavity approach leads to efficient......We report the realization of a tapered diode laser operated in a coupled ring cavity that significantly improves the coherence properties of the tapered laser and efficiently generates tunable light at the second harmonic frequency. The tapered diode laser is tunable with single-frequency output...... frequency doubling. More than 500 mW green output power is obtained by placing a periodically poled LiNbO3 crystal in the external cavity. The single frequency green output from the laser system is tunable in the 530 nm to 533 nm range limited by the LiNbO3 crystal. The optical to optical conversion...

  11. Cavity optomechanics in gallium phosphide microdisks

    International Nuclear Information System (INIS)

    Mitchell, Matthew; Barclay, Paul E.; Hryciw, Aaron C.

    2014-01-01

    We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors >2.8 × 10 5 and mode volumes 3 , and study their nonlinear and optomechanical properties. For optical intensities up to 8.0 × 10 4 intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5 μm and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate g 0 /2π∼30 kHz for the fundamental mechanical radial breathing mode at 488 MHz

  12. Cavity-enhanced eigenmode and angular hybrid multiplexing in holographic data storage systems.

    Science.gov (United States)

    Miller, Bo E; Takashima, Yuzuru

    2016-12-26

    Resonant optical cavities have been demonstrated to improve energy efficiencies in Holographic Data Storage Systems (HDSS). The orthogonal reference beams supported as cavity eigenmodes can provide another multiplexing degree of freedom to push storage densities toward the limit of 3D optical data storage. While keeping the increased energy efficiency of a cavity enhanced reference arm, image bearing holograms are multiplexed by orthogonal phase code multiplexing via Hermite-Gaussian eigenmodes in a Fe:LiNbO3 medium with a 532 nm laser at two Bragg angles. We experimentally confirmed write rates are enhanced by an average factor of 1.1, and page crosstalk is about 2.5%. This hybrid multiplexing opens up a pathway to increase storage density while minimizing modification of current angular multiplexing HDSS.

  13. Study of UV surface plasmons on metallic nanostructures and its applications to nanophotonics

    Science.gov (United States)

    Zhou, Liangcheng

    Modern nanotechnology requires the characterization ability in the order of 100 nm or smaller. This resolution requirement cannot be met by using conventional optical microscopy. Nowadays, the mainstream technique that is universally adopted to characterize optical properties on this length scale is Near-field Scanning Optical Microscopy (NSOM). In the effort to improve the resolution and efficiency of NSOM techniques, both nanoscopic fabrication and imaging techniques are critical because the light field strongly intereacts with the metallic NSOM probe or other surfaces to form surface plasmons (SPs). However, much is still unknown about the behavior of light interacting with metallic nanostructures. This calls for research that develops the tool set, methodology and that includes both experimental characterization, and numerical simulations, for the investigation of SPs. The short wavelength of UV light makes it particularly desirable for many industrial processes. So far, little research has been carried out to understand surface plasmon in the UV spectral region. Like conventional optics, UV SPs have unique properties and optical behavior. For this purpose, we modified our existing NSOM into a Photon Scanning Tunneling Microscope (PTSM) and demonstrate its power for the imaging of UV SPs. We present what we believe to be the first direct mapping of the UV SPs on an Al2O3/Al surface. UV SP modes launched by one-dimensional slits or two-dimensional groove arrays and corresponding interference phenomenon were both observed. We then use the same methodology in the engineering of optimized nano aperture such as UV bowtie nanoantenna. For the latter, we find a strong UV intensity profile which is localized to less than 50nm caused by a localized surface plasmon resonance. The relationship of optical field enhancement and antenna geometric shape is studied using numerical simulations and NSOM experiments. In another project, we examine the propagation of light from

  14. CW substrate-free metal-cavity surface microemitters at 300 K

    International Nuclear Information System (INIS)

    Lu, Chien-Yao; Chang, Shu-Wei; Chuang, Shun Lien; Germann, Tim D; Pohl, Udo W; Bimberg, Dieter

    2011-01-01

    In this paper substrate-free metal-cavity surface microemitters are demonstrated. The optical cavity is formed by a metal reflector, metal-surrounded sidewall and n-doped distributed-Bragg reflector, which provides optical feedback and carrier injection. We describe a simple design principle with the modal properties modified by geometry and metal-insulator cladding. Both resonant cavity light-emitting diodes (1.85 µm diameter and 0.6 µm height) and lasers (2.0 µm diameter and 2.5 µm height) are successfully fabricated and characterized. These two types of devices operate at room temperature under continuous-wave (CW) operation. Since the devices are substrate-free, they can be bonded to any substrates. From the threshold currents of the lasers, we obtain a high characteristic temperature of 425 K in the range of 10–27 °C. We also discuss a general approach to improve the diffraction from small-aperture devices

  15. Hybrid III-V-on-Si Vertical Cavity laser for Optical Interconnects

    DEFF Research Database (Denmark)

    Park, Gyeong Cheol; Semenova, Elizaveta; Chung, Il-Sug

    2013-01-01

    Combining a III-V active material onto the Si platform is an attractive approach for silicon photonics light source. We have developed fabrication methods for novel III-V on Si vertical cavity lasers.......Combining a III-V active material onto the Si platform is an attractive approach for silicon photonics light source. We have developed fabrication methods for novel III-V on Si vertical cavity lasers....

  16. Upstream vertical cavity surface-emitting lasers for fault monitoring and localization in WDM passive optical networks

    Science.gov (United States)

    Wong, Elaine; Zhao, Xiaoxue; Chang-Hasnain, Connie J.

    2008-04-01

    As wavelength division multiplexed passive optical networks (WDM-PONs) are expected to be first deployed to transport high capacity services to business customers, real-time knowledge of fiber/device faults and the location of such faults will be a necessity to guarantee reliability. Nonetheless, the added benefit of implementing fault monitoring capability should only incur minimal cost associated with upgrades to the network. In this work, we propose and experimentally demonstrate a fault monitoring and localization scheme based on a highly-sensitive and potentially low-cost monitor in conjunction with vertical cavity surface-emitting lasers (VCSELs). The VCSELs are used as upstream transmitters in the WDM-PON. The proposed scheme benefits from the high reflectivity of the top distributed Bragg reflector (DBR) mirror of optical injection-locked (OIL) VCSELs to reflect monitoring channels back to the central office for monitoring. Characterization of the fault monitor demonstrates high sensitivity, low bandwidth requirements, and potentially low output power. The added advantage of the proposed fault monitoring scheme incurs only a 0.5 dB penalty on the upstream transmissions on the existing infrastructure.

  17. Calculation, normalization and perturbation of quasinormal modes in coupled cavity-waveguide systems

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; de Lasson, Jakob Rosenkrantz; Gregersen, Niels

    2014-01-01

    of divergent series to provide a framework for modeling of optical phenomena in such coupled cavity-waveguide systems. As an example, we apply the framework to study perturbative changes in the resonance frequency and Q value of a photonic crystal cavity coupled to a defect waveguide....

  18. Directional amplifier in an optomechanical system with optical gain

    Science.gov (United States)

    Jiang, Cheng; Song, L. N.; Li, Yong

    2018-05-01

    Directional amplifiers are crucial nonreciprocal devices in both classical and quantum information processing. Here we propose a scheme for realizing a directional amplifier between optical and microwave fields based on an optomechanical system with optical gain, where an active optical cavity and two passive microwave cavities are coupled to a common mechanical resonator via radiation pressure. The two passive cavities are coupled via hopping interaction to facilitate the directional amplification between the active and passive cavities. We obtain the condition of achieving optical directional amplification and find that the direction of amplification can be controlled by the phase differences between the effective optomechanical couplings. The effects of the gain rate of the active cavity and the effective coupling strengths on the maximum gain of the amplifier are discussed. We show that the noise added to this amplifier can be greatly suppressed in the large cooperativity limit.

  19. Control of emitted light polarization in a 1310 nm dilute nitride spin-vertical cavity surface emitting laser subject to circularly polarized optical injection

    Energy Technology Data Exchange (ETDEWEB)

    Alharthi, S. S., E-mail: ssmalh@essex.ac.uk; Hurtado, A.; Al Seyab, R. K.; Henning, I. D.; Adams, M. J. [School of Computer Science and Electronic Engineering, University of Essex, Wivenhoe Park, Colchester CO4 3SQ (United Kingdom); Korpijarvi, V.-M.; Guina, M. [Optoelectronics Research Centre (ORC), Tampere University of Technology, P.O. Box 692, FIN-33101 Tampere (Finland)

    2014-11-03

    We experimentally demonstrate the control of the light polarization emitted by a 1310 nm dilute nitride spin-Vertical Cavity Surface Emitting Laser (VCSEL) at room temperature. This is achieved by means of a combination of polarized optical pumping and polarized optical injection. Without external injection, the polarization of the optical pump controls that of the spin-VCSEL. However, the addition of the externally injected signal polarized with either left- (LCP) or right-circular polarization (RCP) is able to control the polarization of the spin-VCSEL switching it at will to left- or right-circular polarization. A numerical model has been developed showing a very high degree of agreement with the experimental findings.

  20. A comparison study of Riboflavin/UV-A and Rose-Bengal/Green light cross-linking of the rabbit corneas using optical coherence elastography

    Science.gov (United States)

    Li, Jiasong; Singh, Manmohan; Han, Zhaolong; Vantipalli, Srilatha; Liu, Chih-Hao; Wu, Chen; Raghunathan, Raksha; Kazemi, Tina; Twa, Michael D.; Larin, Kirill V.

    2016-03-01

    The biomechanical properties of the cornea are critical factors which determine its health and subsequent visual acuity. Keratoconus is a structural degeneration of the cornea which can diminish vision quality. Riboflavin/UV-A corneal collagen cross-linking (UV-CXL) is an emerging treatment that increases the stiffness of the cornea and improves its ability to resist further degeneration. While UV-CXL has shown great promise for effective therapy of the keratoconus, there are concerns associated with the UV irradiation, such as keratocyte cytotoxicity. Rose-bengal/green light corneal collagen cross-linking (RGX) has been proposed as an alternative to UV-CXL. Because of the high absorbance of the rose-bengal dye at green wavelengths, the treatment time is significantly shorter than with UV-CXL. Moreover, because green light is used in lieu of UV irradiation, there are no cytotoxic side-effects. In this study, noncontact optical coherence elastography (OCE) was used to compare the outcomes of UV-CXL and RGX treatment in rabbit cornea. Low-amplitude (micrometer scale) elastic waves were induced by a focused air-pulse loading system. The elastic wave propagation was then imaged by a phase-stabilized swept source OCE (PhS-SSOCE) system. The changes in the viscoelasticity of the corneas were quantified by a previously developed modified Rayleigh Lamb frequency model. The depth-resolved micro-scale phase-velocity distribution in the cornea was used to reveal the depth-wise heterogeneity before and after both cross-linking techniques. Our results show that UV-CXL and RGX increased the stiffness of the corneas by ~54% and ~5% while reducing the viscosity by ~42% and ~17%, respectively. The depth-wise phase velocities showed that UV-CXL affected the anterior ~1/3 of the corneas, while RGX only affected the anterior ~1/7 of the corneas.

  1. THE LONG-LIVED UV ''PLATEAU'' OF SN 2012aw

    Energy Technology Data Exchange (ETDEWEB)

    Bayless, Amanda J.; Roming, Peter W. A. [Southwest Research Institute, Department of Space Science, 6220 Culebra Road, San Antonio, TX 78238 (United States); Pritchard, Tyler A. [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA 16802 (United States); Kuin, Paul [Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Brown, Peter J. [Texas A and M University, Department of Physics and Astronomy, College Station, TX 77843-4242 (United States); Botticella, Maria Teresa; Dall' Ora, Massimo [INAF-Osservatorio Astronomico di Capodimonte, via Moiariello 16, I-80131 Napoli (Italy); Frey, Lucille H.; Even, Wesley; Fryer, Chris L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Maund, Justyn R.; Fraser, Morgan [Astrophysics Research Center, School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom)

    2013-02-10

    Observations with the Swift UV Optical Telescope have unambiguously uncovered for the first time a long-lived, UV ''plateau'' in a Type II-P supernova (SN). Although this flattening in slope is hinted at in a few other SNe, due to its proximity and minimal line-of-sight extinction, SN 2012aw has afforded the first opportunity to clearly observe this UV plateau. The observations of SN 2012aw revealed all Swift UV and u-band light curves initially declined rapidly, but 27 days after the explosion the light curves flattened. Some possible sources of the UV plateau are the same thermal process that causes the optical plateau, heating from radioactive decay, or a combination of both processes.

  2. Three-Dimensional Morphology of a Coronal Prominence Cavity

    Science.gov (United States)

    Gibson, S. E.; Kucera, T. A.; Rastawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hill, S.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; hide

    2010-01-01

    We present a three-dimensional density model of coronal prominence cavities, and a morphological fit that has been tightly constrained by a uniquely well-observed cavity. Observations were obtained as part of an International Heliophysical Year campaign by instruments from a variety of space- and ground-based observatories, spanning wavelengths from radio to soft-X-ray to integrated white light. From these data it is clear that the prominence cavity is the limb manifestation of a longitudinally-extended polar-crown filament channel, and that the cavity is a region of low density relative to the surrounding corona. As a first step towards quantifying density and temperature from campaign spectroscopic data, we establish the three-dimensional morphology of the cavity. This is critical for taking line-of-sight projection effects into account, since cavities are not localized in the plane of the sky and the corona is optically thin. We have augmented a global coronal streamer model to include a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. We have developed a semi-automated routine that fits ellipses to cross-sections of the cavity as it rotates past the solar limb, and have applied it to Extreme Ultraviolet Imager (EUVI) observations from the two Solar Terrestrial Relations Observatory (STEREO) spacecraft. This defines the morphological parameters of our model, from which we reproduce forward-modeled cavity observables. We find that cavity morphology and orientation, in combination with the viewpoints of the observing spacecraft, explains the observed variation in cavity visibility for the east vs. west limbs

  3. A chip-scale integrated cavity-electro-optomechanics platform

    DEFF Research Database (Denmark)

    Winger, M.; Blasius, T. D.; Mayer Alegre, T. P.

    2011-01-01

    We present an integrated optomechanical and electromechanical nanocavity, in which a common mechanical degree of freedom is coupled to an ultrahigh-Q photonic crystal defect cavity and an electrical circuit. The system allows for wide-range, fast electrical tuning of the optical nanocavity...... resonances, and for electrical control of optical radiation pressure back-action effects such as mechanical amplification (phonon lasing), cooling, and stiffening. These sort of integrated devices offer a new means to efficiently interconvert weak microwave and optical signals, and are expected to pave...

  4. The Optical/UV Excess of X-Ray-dim Isolated Neutron Stars. I. Bremsstrahlung Emission from a Strangeon Star Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weiyang; Lu, Jiguang; Men, Yunpeng; Xu, Renxin [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Tong, Hao [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011 (China); Ge, Mingyu [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Li, Zhaosheng, E-mail: r.x.xu@pku.edu.cn [Department of Physics, Xiangtan University, Xiangtan 411105 (China)

    2017-03-01

    X-ray-dim isolated neutron stars (XDINSs) are characterized by Planckian spectra in X-ray bands, but show optical/ultraviolet (UV) excesses: the factors by which the measured photometry exceeds those extrapolated from X-ray spectra. To solve this problem, a radiative model of bremsstrahlung emission from a plasma atmosphere is established in the regime of a strangeon star. A strangeon star atmosphere could simply be regarded as the upper layer of a normal neutron star. This plasma atmosphere, formed and maintained by the interstellar-medium-accreted matter due to the so-called strangeness barrier, is supposed to be of two temperatures. All seven XDINS spectra could be well fitted by the radiative model, from optical/UV to X-ray bands. The fitted radiation radii of XDINSs are from 7 to 13 km, while the modeled electron temperatures are between 50 and 250 eV, except RX J0806.4–4123, with a radiation radius of ∼3.5 km, indicating that this source could be a low-mass strangeon star candidate. This strangeon star model could further be tested by soft X-ray polarimetry, such as the Lightweight Asymmetry and Magnetism Probe, which is expected to be operational on China’s space station around 2020.

  5. Path to a UV/Optical/IR Flagship: Review of ATLAST and Its Predecessors

    Science.gov (United States)

    Thronson, Harley; Bolcar, Matthew R.; Clampin, Mark; Crooke, Julie; Feinberg, Lee; Oegerle, William; Rioux, Norman; Stahl, H. Philip; Stapelfeldt, Karl

    2016-01-01

    Our recently completed study for the Advanced Technology Large-Aperture Space Telescope (ATLAST) was the culmination of three years of initially internally funded work that built upon earlier engineering designs, science objectives, and technology priorities. Beginning in the mid-1980s, multiple teams of astronomers, technologists, and engineers developed concepts for a large-aperture UV/optical/IR space observatory intended to follow the Hubble Space Telescope (HST). Here, we summarize since the first significant conferences on major post-HST ultraviolet, optical, and infrared (UVOIR) observatories the history of designs, scientific goals, key technology recommendations, and community workshops. Although the sophistication of science goals and the engineering designs both advanced over the past three decades, we note the remarkable constancy of major characteristics of large post-HST UVOIR concepts. As it has been a priority goal for NASA and science communities for a half-century, and has driven much of the technology priorities for major space observatories, we include the long history of concepts for searching for Earth-like worlds. We conclude with a capsule summary of our ATLAST reference designs developed by four partnering institutions over the past three years, which was initiated in 2013 to prepare for the 2020 National Academies' Decadal Survey.

  6. Challenges of UV light processing of low UVT foods and beverages

    Science.gov (United States)

    Koutchma, Tatiana

    2010-08-01

    Ultraviolet (UV) technology holds promise as a low cost non-thermal alternative to heat pasteurization of liquid foods and beverages. However, its application for foods is still limited due to low UV transmittance (LUVT). LUVT foods have a diverse range of chemical (pH, Brix, Aw), physical (density and viscosity) and optical properties (absorbance and scattering) that are critical for systems and process designs. The commercially available UV sources tested for foods include low and medium pressure mercury lamps (LPM and MPM), excimer and pulsed lamps (PUV). The LPM and excimer lamps are monochromatic sources whereas emission of MPM and PUV is polychromatic. The optimized design of UV-systems and UV-sources with parameters that match to specific product spectra have a potential to make UV treatments of LUVT foods more effective and will serve its further commercialization. In order to select UV source for specific food application, processing effects on nutritional, quality, sensorial and safety markers have to be evaluated. This paper will review current status of UV technology for food processing along with regulatory requirements. Discussion of approaches and results of measurements of chemico-physical and optical properties of various foods (fresh juices, milk, liquid whey proteins and sweeteners) that are critical for UV process and systems design will follow. Available UV sources did not prove totally effective either resulting in low microbial reduction or UV over-dosing of the product thereby leading to sensory changes. Beam shaping of UV light presents new opportunities to improve dosage uniformity and delivery of UV photons in LUVT foods.

  7. Studies of aluminium nitride ceramics for application in UV dosimetry

    DEFF Research Database (Denmark)

    Trinkler, L.; Bøtter-Jensen, L.; Christensen, P.

    2000-01-01

    The study is reported of the ceramic material AlN-Y2O3 as a potential luminescence dosemeter for the detection of UV radiation. Both the thermoluminescence and the optically stimulated luminescence properties of the material have been studied after exposure to UV radiation and compared with those...... of the widely used dosemeter material Al2O3:C. It has been shown that AlN-Y2O3 ceramics exhibit three orders of magnitude higher sensitivity to UV radiation than does Al2O3,:C over a broad spectral region. The thermoluminescence from AlN-Y2O3 is characterised by linear dose dependence over a wide range....... The fading characteristics of the UV-induced thermoluminescence and optically stimulated luminescence signals with storage time at room temperature were found to be a drawback, but still lower than those induced after exposure to ionising radiation....

  8. 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.

  9. Characterisation of vortex flow inside an entrained cavity

    Energy Technology Data Exchange (ETDEWEB)

    Rambert, A.; Elcafsi, A.; Gougat, P. [Centre National de la Recherche Scientifique, 91 - Orsay (France). Lab. d' Informatique pour la Mecanique et les Sciences de l' Ingenieur

    2000-07-01

    A number of studies have referred to the existence of a vortex cell within an urban street canyon when ambient winds aloft are perpendicular to the street. The understanding of vortex dynamics or vorticity distribution in a such configuration is of great interest. Vortex structures play an important role in the dynamics of pollutant dispersion. This configuration was simulated by the interaction between a boundary layer and a cavity. Experimental characterisation of the vortex structures evolution was developed by flow velocity measurements inside and out of the cavity. Classical methods like hot wire and laser Doppler velocimetry (LDV) display only local measurements. Particle image velocimetry (PIV) method based on the optical flow technique permitted global velocity measurements. This technique emphasis the vortex structures inside the cavity which present small scales as well as large scales related to the cavity geometry. These vortices are usually non-stationary. (orig.)

  10. UV and vacuum-UV biological spectroscopy using synchrotron radiation

    International Nuclear Information System (INIS)

    Ito, Amando Siuiti

    1996-01-01

    Full text. Synchrotron radiation has been used as light source in the UV and VUV region for the study of many biological systems. In the time domain, measurements are made that allow the observation of dynamics and kinetics of biomolecules like proteins and peptides, using the fluorescent properties of either intrinsic or extrinsic probes. Optical activity of groups inside biomolecules allows the use of circular dichroism techniques to generate structural information and to follow processes like protein folding. Confocal scanning of synchrotron light generates microscopy resolution below 100 nm, allowing the creation of high quality three dimensional images of biological samples, and the collection of fluorescence originated from microvolumes inside the samples. We propose a station at LNLS for these three techniques: time-resolved fluorescence, circular dischroism and confocal microscopy, using UV and VUV light. (author)

  11. X-Ray Brightening and UV Fading of Tidal Disruption Event ASASSN-15oi

    Science.gov (United States)

    Gezari, S.; Cenko, S. B.; Arcavi, I.

    2017-12-01

    We present late-time observations by Swift and XMM-Newton of the tidal disruption event (TDE) ASASSN-15oi that reveal that the source brightened in the X-rays by a factor of ∼10 one year after its discovery, while it faded in the UV/optical by a factor of ∼100. The XMM-Newton observations measure a soft X-ray blackbody component with {{kT}}{bb}∼ 45 {eV}, corresponding to radiation from several gravitational radii of a central ∼ {10}6 {M}ȯ black hole. The last Swift epoch taken almost 600 days after discovery shows that the X-ray source has faded back to its levels during the UV/optical peak. The timescale of the X-ray brightening suggests that the X-ray emission could be coming from delayed accretion through a newly forming debris disk and that the prompt UV/optical emission is from the prior circularization of the disk through stream–stream collisions. The lack of spectral evolution during the X-ray brightening disfavors ionization breakout of a TDE “veiled” by obscuring material. This is the first time a TDE has been shown to have a delayed peak in soft X-rays relative to the UV/optical peak, which may be the first clear signature of the real-time assembly of a nascent accretion disk, and provides strong evidence for the origin of the UV/optical emission from circularization, as opposed to reprocessed emission of accretion radiation.

  12. Plasma-cavity ringdown spectroscopy for analytical measurement: Progress and prospectives

    Science.gov (United States)

    Zhang, Sida; Liu, Wei; Zhang, Xiaohe; Duan, Yixiang

    2013-07-01

    Plasma-cavity ringdown spectroscopy is a powerful absorption technique for analytical measurement. It combines the inherent advantages of high sensitivity, absolute measurement, and relative insensitivity to light source intensity fluctuations of the cavity ringdown technique with use of plasma as an atomization/ionization source. In this review, we briefly describe the background and principles of plasma-cavity ringdown spectroscopy(CRDS) technology, the instrumental components, and various applications. The significant developments of the plasma sources, lasers, and cavity optics are illustrated. Analytical applications of plasma-CRDS for elemental detection and isotopic measurement in atomic spectrometry are outlined in this review. Plasma-CRDS is shown to have a promising future for various analytical applications, while some further efforts are still needed in fields such as cavity design, plasma source design, instrumental improvement and integration, as well as potential applications in radical and molecular measurements.

  13. Plasma-cavity ringdown spectroscopy for analytical measurement: Progress and prospectives

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Sida; Liu, Wei [Research Center of Analytical Instrumentation, Analytical and Testing Center, College of Chemistry, Sichuan University, Chengdu (China); Zhang, Xiaohe [College of Water Resources and Hydropower, Sichuan University, Chengdu (China); Duan, Yixiang, E-mail: yduan@scu.edu.cn [Research Center of Analytical Instrumentation, Analytical and Testing Center, College of Chemistry, Sichuan University, Chengdu (China)

    2013-07-01

    Plasma-cavity ringdown spectroscopy is a powerful absorption technique for analytical measurement. It combines the inherent advantages of high sensitivity, absolute measurement, and relative insensitivity to light source intensity fluctuations of the cavity ringdown technique with use of plasma as an atomization/ionization source. In this review, we briefly describe the background and principles of plasma-cavity ringdown spectroscopy(CRDS) technology, the instrumental components, and various applications. The significant developments of the plasma sources, lasers, and cavity optics are illustrated. Analytical applications of plasma-CRDS for elemental detection and isotopic measurement in atomic spectrometry are outlined in this review. Plasma-CRDS is shown to have a promising future for various analytical applications, while some further efforts are still needed in fields such as cavity design, plasma source design, instrumental improvement and integration, as well as potential applications in radical and molecular measurements. - Highlights: • Plasma-based cavity ringdown spectroscopy • High sensitivity and high resolution • Elemental and isotopic measurements.

  14. Chiral cavity ring down polarimetry: Chirality and magnetometry measurements using signal reversals.

    Science.gov (United States)

    Bougas, Lykourgos; Sofikitis, Dimitris; Katsoprinakis, Georgios E; Spiliotis, Alexandros K; Tzallas, Paraskevas; Loppinet, Benoit; Rakitzis, T Peter

    2015-09-14

    We present the theory and experimental details for chiral-cavity-ring-down polarimetry and magnetometry, based on ring cavities supporting counterpropagating laser beams. The optical-rotation symmetry is broken by the presence of both chiral and Faraday birefringence, giving rise to signal reversals which allow rapid background subtractions. We present the measurement of the specific rotation at 800 nm of vapors of α-pinene, 2-butanol, and α-phellandrene, the measurement of optical rotation of sucrose solutions in a flow cell, the measurement of the Verdet constant of fused silica, and measurements and theoretical treatment of evanescent-wave optical rotation at a prism surface. Therefore, these signal-enhancing and signal-reversing methods open the way for ultrasensitive polarimetry measurements in gases, liquids and solids, and at surfaces.

  15. Resonant cavity enhanced light harvesting in flexible thin-film organic solar cells

    KAUST Repository

    Sergeant, Nicholas P.

    2013-04-24

    Dielectric/metal/dielectric (DMD) electrodes have the potential to significantly increase the absorption efficiency and photocurrent in flexible organic solar cells. We demonstrate that this enhancement is attributed to a broadband cavity resonance. Silver-based semitransparent DMD electrodes with sheet resistances below 10 ohm/sq. are fabricated on flexible polyethylene terephthalate (PET) substrates in a high-throughput roll-to-roll sputtering tool. We carefully study the effect of the semitransparent DMD electrode (here composed of ZnxSnyOz/Ag/InxSn yOz) on the optical device performance of a copper phthalocyanine (CuPc)/fullerene (C60) bilayer cell and illustrate that a resonant cavity enhanced light trapping effect dominates the optical behavior of the device. © 2013 Optical Society of America.

  16. Chiral cavity ring down polarimetry: Chirality and magnetometry measurements using signal reversals

    International Nuclear Information System (INIS)

    Bougas, Lykourgos; Sofikitis, Dimitris; Katsoprinakis, Georgios E.; Spiliotis, Alexandros K.; Rakitzis, T. Peter; Tzallas, Paraskevas; Loppinet, Benoit

    2015-01-01

    We present the theory and experimental details for chiral-cavity-ring-down polarimetry and magnetometry, based on ring cavities supporting counterpropagating laser beams. The optical-rotation symmetry is broken by the presence of both chiral and Faraday birefringence, giving rise to signal reversals which allow rapid background subtractions. We present the measurement of the specific rotation at 800 nm of vapors of α-pinene, 2-butanol, and α-phellandrene, the measurement of optical rotation of sucrose solutions in a flow cell, the measurement of the Verdet constant of fused silica, and measurements and theoretical treatment of evanescent-wave optical rotation at a prism surface. Therefore, these signal-enhancing and signal-reversing methods open the way for ultrasensitive polarimetry measurements in gases, liquids and solids, and at surfaces

  17. High efficiency and good beam quality of electro-optic, cavity-dumped and double-end pumped Nd:YLF laser

    Science.gov (United States)

    Tang, X. X.; Fan, Z. W.; Qiu, J. S.; Lian, F. Q.; Zhang, X. L.

    2012-06-01

    In this paper, we describe a Nd:YLF laser based on high-speed RTP electro-optical cavity dumping technique. Two home-made 150 W fiber pump modules are used from both sides to pump Nd:YLF crystal. Coupling systems are the key elements in end-pumped solid-state lasers, the aberrations of which greatly affect the efficiency of the lasers. In order to get high efficient and good quality laser output, the optical software ZEMAX is used to design a four-piece coupling system. When the pumped energy is 32 mJ at the repetition rate of 1 Hz, the output energy is 6.5 mJ with 2.5 ns pulse width. When the pumped energy is 13.1 W at the repetition rate of 200 Hz, the output energy is 2.2 W with small M 2 factor where M {/x 2} is 1.04, and M {/y 2} is 1.05, and the light-light conversion efficiency is up to 16.8%.

  18. A microfabricated, low dark current a-Se detector for measurement of microplasma optical emission in the UV for possible use on-site

    Science.gov (United States)

    Abbaszadeh, Shiva; Karim, Karim S.; Karanassios, Vassili

    2013-05-01

    Traditionally, samples are collected on-site (i.e., in the field) and are shipped to a lab for chemical analysis. An alternative is offered by using portable chemical analysis instruments that can be used on-site (i.e., in the field). Many analytical measurements by optical emission spectrometry require use of light-sources and of spectral lines that are in the Ultra-Violet (UV, ~200 nm - 400 nm wavelength) region of the spectrum. For such measurements, a portable, battery-operated, fiber-optic spectrometer equipped with an un-cooled, linear, solid-state detector may be used. To take full advantage of the advanced measurement capabilities offered by state-of-the-art solid-state detectors, cooling of the detector is required. But cooling and other thermal management hamper portability and use on-site because they add size and weight and they increase electrical power requirements. To address these considerations, an alternative was implemented, as described here. Specifically, a microfabricated solid-state detector for measurement of UV photons will be described. Unlike solid-state detectors developed on crystalline Silicon, this miniaturized and low-cost detector utilizes amorphous Selenium (a-Se) as its photosensitive material. Due to its low dark current, this detector does not require cooling, thus it is better suited for portable use and for chemical measurements on-site. In this paper, a microplasma will be used as a light-source of UV photons for the a-Se detector. For example, spectra acquired using a microplasma as a light-source will be compared with those obtained with a portable, fiber-optic spectrometer equipped with a Si-based 2080-element detector. And, analytical performance obtained by introducing ng-amounts of analytes into the microplasma will be described.

  19. Multistate intermittency on the route to chaos of a semiconductor laser subjected to optical feedback from a long external cavity.

    Science.gov (United States)

    Choi, Daeyoung; Wishon, Michael J; Chang, C Y; Citrin, D S; Locquet, A

    2018-01-01

    We observe experimentally two regimes of intermittency on the route to chaos of a semiconductor laser subjected to optical feedback from a long external cavity as the feedback level is increased. The first regime encountered corresponds to multistate intermittency involving two or three states composed of several combinations of periodic, quasiperiodic, and subharmonic dynamics. The second regime is observed for larger feedback levels and involves intermittency between period-doubled and chaotic regimes. This latter type of intermittency displays statistical properties similar to those of on-off intermittency.

  20. UV writing of advanced Bragg gratings in optical waveguides

    DEFF Research Database (Denmark)

    Jensen, Jesper Bo Damm

    2002-01-01

    of the novel polarization control method for UV writing of Bragg gratings with advanced apodization profiles including phase shifts. The principle of the polarization control method relies on a spatial separation of the s- and p-polarized components of a linearly polarized UV beam corresponding to half......, Technical University of Denmark. During fabrication the planar waveguides were annealed in an oxygen rich atmosphere. This reduces the photosensitivity to a negligible level and Bragg gratings cannot be written within reasonable time unless the waveguides are sensitized by deuterium loading. Samples were...

  1. Scheme for secure swapping two unknown states of a photonic qubit and an electron-spin qubit using simultaneous quantum transmission and teleportation via quantum dots inside single-sided optical cavities

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Jino [College of Electrical and Computer Engineering, Chungbuk National University, Chungdae-ro 1, Seowon-Gu, Cheongju (Korea, Republic of); Kang, Min-Sung [Center for Quantum Information, Korea Institute of Science and Technology (KIST), Seoul, 136-791 (Korea, Republic of); Hong, Chang-Ho [National Security Research Institute, P.O.Box 1, Yuseong, Daejeon, 34188 (Korea, Republic of); Choi, Seong-Gon [College of Electrical and Computer Engineering, Chungbuk National University, Chungdae-ro 1, Seowon-Gu, Cheongju (Korea, Republic of); Hong, Jong-Phil, E-mail: jongph@cbnu.ac.kr [College of Electrical and Computer Engineering, Chungbuk National University, Chungdae-ro 1, Seowon-Gu, Cheongju (Korea, Republic of)

    2017-06-15

    We propose a scheme for swapping two unknown states of a photon and electron spin confined to a charged quantum dot (QD) between two users by transferring a single photon. This scheme simultaneously transfers and teleports an unknown state (electron spin) between two users. For this bidirectional quantum communication, we utilize the interactions between a photonic and an electron-spin qubits of a QD located inside a single-sided optical cavity. Thus, our proposal using QD-cavity systems can obtain a certain success probability with high fidelity. Furthermore, compared to a previous scheme using cross-Kerr nonlinearities and homodyne detections, our scheme (using QD-cavity systems) can improve the feasibility under the decoherence effect in practice. - Highlights: • Design of Simultaneous quantum transmission and teleportation scheme via quantum dots and cavities. • We have developed the experimental feasibility of this scheme compared with the existing scheme. • Analysis of some benefits when our scheme is experimentally implemented using quantum dots and single-sided cavities.

  2. Tunable optical nonreciprocity and a phonon-photon router in an optomechanical system with coupled mechanical and optical modes

    Science.gov (United States)

    Li, Guolong; Xiao, Xiao; Li, Yong; Wang, Xiaoguang

    2018-02-01

    We propose a multimode optomechanical system to realize tunable optical nonreciprocity that has the prospect of making an optical diode for information technology. The proposed model consists of two subsystems, each of which contains two optical cavities, injected with a classical field and a quantum signal via a 50:50 beam splitter, and a mechanical oscillator, coupled to both cavities via optomechanical coupling. Meanwhile two cavities and an oscillator in a subsystem are respectively coupled to their corresponding cavities and an oscillator in the other subsystem. Our scheme yields nonreciprocal effects at different frequencies with opposite directions, but each effective linear optomechanical coupling can be controlled by an independent classical one-frequency pump. With this setup one is able to apply quantum states with large fluctuations, which extends the scope of applicable quantum states, and exploit the independence of paths. Moreover, the optimal frequencies for nonreciprocal effects can be controlled by adjusting the relevant parameters. We also exhibit the path switching of two directions, from a mechanical input to two optical output channels, via tuning the signal frequency. In experiment, the considered scheme can be tuned to reach small damping rates of the oscillators relative to those of the cavities, which is more practical and requires less power than in previous schemes.

  3. Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications

    Science.gov (United States)

    Affolderbach, C.; Moreno, W.; Ivanov, A. E.; Debogovic, T.; Pellaton, M.; Skrivervik, A. K.; de Rijk, E.; Mileti, G.

    2018-03-01

    Additive manufacturing (AM) of passive microwave components is of high interest for the cost-effective and rapid prototyping or manufacture of devices with complex geometries. Here, we present an experimental study on the properties of recently demonstrated microwave resonator cavities manufactured by AM, in view of their applications to high-performance compact atomic clocks. The microwave cavities employ a loop-gap geometry using six electrodes. The critical electrode structures were manufactured monolithically using two different approaches: Stereolithography (SLA) of a polymer followed by metal coating and Selective Laser Melting (SLM) of aluminum. The tested microwave cavities show the desired TE011-like resonant mode at the Rb clock frequency of ≈6.835 GHz, with a microwave magnetic field highly parallel to the quantization axis across the vapor cell. When operated in an atomic clock setup, the measured atomic Rabi oscillations are comparable to those observed for conventionally manufactured cavities and indicate a good uniformity of the field amplitude across the vapor cell. Employing a time-domain Ramsey scheme on one of the SLA cavities, high-contrast (34%) Ramsey fringes are observed for the Rb clock transition, along with a narrow (166 Hz linewidth) central fringe. The measured clock stability of 2.2 × 10-13 τ-1/2 up to the integration time of 30 s is comparable to the current state-of-the-art stabilities of compact vapor-cell clocks based on conventional microwave cavities and thus demonstrates the feasibility of the approach.

  4. A chip-scale integrated cavity-electro-optomechanics platform.

    Science.gov (United States)

    Winger, M; Blasius, T D; Mayer Alegre, T P; Safavi-Naeini, A H; Meenehan, S; Cohen, J; Stobbe, S; Painter, O

    2011-12-05

    We present an integrated optomechanical and electromechanical nanocavity, in which a common mechanical degree of freedom is coupled to an ultrahigh-Q photonic crystal defect cavity and an electrical circuit. The system allows for wide-range, fast electrical tuning of the optical nanocavity resonances, and for electrical control of optical radiation pressure back-action effects such as mechanical amplification (phonon lasing), cooling, and stiffening. These sort of integrated devices offer a new means to efficiently interconvert weak microwave and optical signals, and are expected to pave the way for a new class of micro-sensors utilizing optomechanical back-action for thermal noise reduction and low-noise optical read-out.

  5. Designing, Probing, and Stabilizing Exotic Fabry-Perot Cavities for Studying Strongly Correlated Light

    Science.gov (United States)

    Ryou, Albert

    Synthetic materials made of engineered quasiparticles are a powerful platform for studying manybody physics and strongly correlated systems due to their bottom-up approach to Hamiltonian modeling. Photonic quasiparticles called polaritons are particularly appealing since they inherit fast dynamics from light and strong interaction from matter. This thesis describes the experimental demonstration of cavity Rydberg polaritons, which are composite particles arising from the hybridization of an optical cavity with Rydberg EIT, as well as the tools for probing and stabilizing the cavity. We first describe the design, construction, and testing of a four-mirror Fabry-Perot cavity, whose small waist size on the order of 10 microns is comparable to the Rydberg blockade radius. By achieving strong coupling between the cavity photon and an atomic ensemble undergoing electromagnetically induced transparency (EIT), we observe the emergence of the dark-state polariton and characterize its single-body properties as well as the single-quantum nonlinearity. We then describe the implementation of a holographic spatial light modulator for exciting different transverse modes of the cavity, an essential tool for studying polariton-polariton scattering. For compensating optical aberrations, we employ a digital micromirror device (DMD), combining beam shaping with adaptive optics to produce diffraction-limited light. We quantitatively measure the purity of the DMD-produced Hermite-Gauss modes and confirm up to 99.2% efficiency. One application of the technique is to create Laguerre-Gauss modes, which have been used to probe synthetic Landau levels for photons in a twisted, nonplanar cavity. Finally, we describe the implementation of an FPGA-based FIR filter for stabilizing the cavity. We digitally cancel the acoustical resonances of the feedback-controlled mechanical system, thereby demonstrating an order-of-magnitude enhancement in the feedback bandwidth from 200 Hz to more than 2 k

  6. Quantum iSWAP gate in optical cavities with a cyclic three-level system

    Science.gov (United States)

    Yan, Guo-an; Qiao, Hao-xue; Lu, Hua

    2018-04-01

    In this paper we present a scheme to directly implement the iSWAP gate by passing a cyclic three-level system across a two-mode cavity quantum electrodynamics. In the scheme, a three-level Δ -type atom ensemble prepared in its ground state mediates the interaction between the two-cavity modes. For this theoretical model, we also analyze its performance under practical noise, including spontaneous emission and the decay of the cavity modes. It is shown that our scheme may have a high fidelity under the practical noise.

  7. High-repetition intra-cavity source of Compton radiation

    International Nuclear Information System (INIS)

    Pogorelsky, I; Polyanskiy, M; Agustsson, R; Campese, T; Murokh, A; Ovodenko, A; Shaftan, T

    2014-01-01

    We report our progress in developing a high-power Compton source for a diversity of applications ranging from university-scale compact x-ray light sources and metrology tools for EUV lithography, to high-brilliance gamma-sources for nuclear analysis. Our conceptual approach lies in multiplying the source’s repetition rate and increasing its average brightness by placing the Compton interaction point inside the optical cavity of an active laser. We discuss considerations in its design, our simulations, and tests of the laser’s cavity that confirm the feasibility of the proposed concept. (paper)

  8. Efficient quality-eactor estimation of a vertical cavity employing a high-contrast grating

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug

    2017-01-01

    Hybrid vertical cavity lasers employing high-contrast grating reflectors are attractive for Si-integrated light source applications. Here, a method for reducing a three-dimensional (3D) optical simulation of this laser structure to lower-dimensional simulations is suggested, which allows for very...... fast and approximate analysis of the quality-factor of the 3D cavity. This approach enables us to efficiently optimize the laser cavity design without performing cumbersome 3D simulations....

  9. AlN ceramics as a detector for UV exposure

    International Nuclear Information System (INIS)

    Trinkler, L.; Berzina, B.; Boetter-Jensen, L.; Christensen, P.; Palcevskis, E.

    1999-01-01

    AlN-Y 2 O 3 ceramics is proposed for application in the field of UV detection and dosimetry. Both thermoluminescence (TL) and optically stimulated luminescence (OSL) signals from the material have been studied after exposure to UV light. AlN-Y 2 O 3 ceramics demonstrates very high sensitivity to UV light over a broad spectral region. The TL is characterized by a linear dose dependence over a large range. The fading rate of the UV-induced TL and OSL signals on storage at room temperature is lower than in the case of exposure to ionizing irradiation. (au)

  10. Generation and spectroscopic signatures of a fractional quantum Hall liquid of photons in an incoherently pumped optical cavity

    Science.gov (United States)

    Umucalılar, R. O.; Carusotto, I.

    2017-11-01

    We investigate theoretically a driven dissipative model of strongly interacting photons in a nonlinear optical cavity in the presence of a synthetic magnetic field. We show the possibility of using a frequency-dependent incoherent pump to create a strongly correlated ν =1 /2 bosonic Laughlin state of light: Due to the incompressibility of the Laughlin state, fluctuations in the total particle number and excitation of edge modes can be tamed by imposing a suitable external potential profile for photons. We further propose angular-momentum-selective spectroscopy of the emitted light as a tool to obtain unambiguous signatures of the microscopic physics of the quantum Hall liquid of light.

  11. Practical aspects of irradiance and energy in UV curing

    International Nuclear Information System (INIS)

    Stowe, R.W.

    1999-01-01

    The physical properties of UV-cured materials are substantially affected by the lamp systems used to cure them. The development of the intended properties, whether a varnish, an ink, or an adhesive, can depend on how well these lamp factors are designed and managed. The four key factors of UV exposure are: UV irradiance (or intensity), spectral distribution (wavelengths) of UV, effective energy (time-integrated UV irradiance), and infrared radiation. Inks and varnishes will exhibit very different response to peak irradiance or energy, as well as to different UV spectra. The ability to identify the various lamp characteristics and match them to the optical properties of the curable materials, widens the range in which UV curing is a faster, more efficient production process. This paper explores the reasons for clearly identifying these factors for process optimization

  12. Creation of a microstructured polymer optical fiber with UV Bragg grating inscription for the detection of extensions at temperatures up to 125°C

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Stajanca, Pavol

    2016-01-01

    We describe the fabrication of a polycarbonate (PC) micro-structured polymer optical fiber (mPOF) and the writing offiber Bragg gratings (FBGs) in it to enable strain and temperature measurements. We demonstrate the photosensitivity ofa dopant-free PC fiber by grating inscription using a UV laser...

  13. Multi-mode competition in an FEL oscillator at perfect synchronism of an optical cavity

    CERN Document Server

    Dong, Z W; Kii, T; Yamazaki, T; Yoshikawa, K

    2002-01-01

    The sustained saturation in a short pulse free electron laser (FEL) oscillator at perfect synchronism of an optical cavity has been observed recently by Japan Atomic Energy Research Institute (JAERI) FEL group by using their super-conducting linac (Phys. Rev. Lett., in preparation). The experiments have clearly shown that FEL efficiency becomes maximum at perfect synchronism, although it has been considered that only a transient state exists at perfect synchronism due to the lethargy effect. Through careful analyses of the experimental condition of JAERI FEL, we found that, in spite of the short length of the electron micro-bunch, the saturation appears due to the following features, which were different from other FEL experiments: (1) very large ratio of the small signal gain to losses, (2) very long electron macro-bunch which can tolerate a slow start up. The saturation and high efficiency at perfect synchronism were benefited from the contribution of the weak sideband instability. In order to analyse these...

  14. New technology and application in UV curing

    International Nuclear Information System (INIS)

    Loutz, J.M.

    1999-01-01

    Overview of radcure technology was presented. Its included this following subjects, radiation curable powder coatings, UV curable water based polyurethanes, photo-initiators, fire retardancy, aqueous systems, cationic, ceramic and optical grade material

  15. Semiconductor quantum optics with tailored photonic nanostructures

    International Nuclear Information System (INIS)

    Laucht, Arne

    2011-01-01

    This thesis describes detailed investigations of the effects of photonic nanostructures on the light emission properties of self-assembled InGaAs quantum dots. Nanoscale optical cavities and waveguides are employed to enhance the interaction between light and matter, i.e. photons and excitons, up to the point where optical non-linearities appear at the quantum (single photon) level. Such non-linearities are an essential component for the realization of hardware for photon based quantum computing since they can be used for the creation and detection of non-classical states of light and may open the way to new genres of quantum optoelectronic devices such as optical modulators and optical transistors. For single semiconductor quantum dots in photonic crystal nanocavities we investigate the coupling between excitonic transitions and the highly localized mode of the optical cavity. We explore the non-resonant coupling mechanisms which allow excitons to couple to the cavity mode, even when they are not spectrally in resonance. This effect is not observed for atomic cavity quantum electrodynamics experiments and its origin is traced to phonon-assisted scattering for small detunings (ΔE ∝5 meV). For quantum dots in high-Q cavities we observe the coherent coupling between exciton and cavity mode in the strong coupling regime of light-matter interaction, probe the influence of pure dephasing on the coherent interaction at high excitation levels and high lattice temperatures, and examine the coupling of two spatially separated quantum dots via the exchange of real and virtual photons mediated by the cavity mode. Furthermore, we study the spontaneous emission properties of quantum dots in photonic crystal waveguide structures, estimate the fraction of all photons emitted into the propagating waveguide mode, and demonstrate the on-chip generation of single photon emission into the waveguide. The results obtained during the course of this thesis contribute significantly to

  16. Characterization of optical systems for the ALPS II experiment

    International Nuclear Information System (INIS)

    Spector, Aaron D.; Baehre, Robin; Willke, Benno; Hannover Univ.

    2016-09-01

    ALPS II is a light shining through a wall style experiment that will use the principle of resonant enhancement to boost the conversion and reconversion probabilities of photons to relativistic WISPs. This will require the use of long baseline low-loss optical cavities. Very high power build up factors in the cavities must be achieved in order to reach the design sensitivity of ALPS II. This necessitates a number of different sophisticated optical and control systems to maintain the resonance and ensure maximal coupling between the laser and the cavity. In this paper we report on the results of the characterization of these optical systems with a 20m cavity and discuss the results in the context of ALPS II.

  17. Entanglement for a Bimodal Cavity Field Interacting with a Two-Level Atom

    International Nuclear Information System (INIS)

    Liu Jia; Chen Ziyu; Bu Shenping; Zhang Guofeng

    2009-01-01

    Negativity has been adopted to investigate the entanglement in a system composed of a two-level atom and a two-mode cavity field. Effects of Kerr-like medium and the number of photon inside the cavity on the entanglement are studied. Our results show that atomic initial state must be superposed, so that the two cavity field modes can be entangled. Moreover, we also conclude that the number of photon in the two cavity mode should be equal. The interaction between modes, namely, the Kerr effect, has a significant negative contribution. Note that the atom frequency and the cavity frequency have an indistinguishable effect, so a corresponding approximation has been made in this article. These results may be useful for quantum information in optics systems.

  18. Hidden Markov Model of atomic quantum jump dynamics in an optically probed cavity

    DEFF Research Database (Denmark)

    Gammelmark, S.; Molmer, K.; Alt, W.

    2014-01-01

    We analyze the quantum jumps of an atom interacting with a cavity field. The strong atom- field interaction makes the cavity transmission depend on the time dependent atomic state, and we present a Hidden Markov Model description of the atomic state dynamics which is conditioned in a Bayesian...... manner on the detected signal. We suggest that small variations in the observed signal may be due to spatial motion of the atom within the cavity, and we represent the atomic system by a number of hidden states to account for both the small variations and the internal state jump dynamics. In our theory...

  19. A compact chaotic laser device with a two-dimensional external cavity structure

    International Nuclear Information System (INIS)

    Sunada, Satoshi; Adachi, Masaaki; Fukushima, Takehiro; Shinohara, Susumu; Arai, Kenichi; Harayama, Takahisa

    2014-01-01

    We propose a compact chaotic laser device, which consists of a semiconductor laser and a two-dimensional (2D) external cavity for delayed optical feedback. The overall size of the device is within 230 μm × 1 mm. A long time delay sufficient for chaos generation can be achieved with the small area by the multiple reflections at the 2D cavity boundary, and the feedback strength is controlled by the injection current to the external cavity. We experimentally demonstrate that a variety of output properties, including chaotic output, can be selectively generated by controlling the injection current to the external cavity.

  20. Spin-controlled ultrafast vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Höpfner, Henning; Lindemann, Markus; Gerhardt, Nils C.; Hofmann, Martin R.

    2014-05-01

    Spin-controlled semiconductor lasers are highly attractive spintronic devices providing characteristics superior to their conventional purely charge-based counterparts. In particular, spin-controlled vertical-cavity surface emitting lasers (spin-VCSELs) promise to offer lower thresholds, enhanced emission intensity, spin amplification, full polarization control, chirp control and ultrafast dynamics. Most important, the ability to control and modulate the polarization state of the laser emission with extraordinarily high frequencies is very attractive for many applications like broadband optical communication and ultrafast optical switches. We present a novel concept for ultrafast spin-VCSELs which has the potential to overcome the conventional speed limitation for directly modulated lasers by the relaxation oscillation frequency and to reach modulation frequencies significantly above 100 GHz. The concept is based on the coupled spin-photon dynamics in birefringent micro-cavity lasers. By injecting spin-polarized carriers in the VCSEL, oscillations of the coupled spin-photon system can by induced which lead to oscillations of the polarization state of the laser emission. These oscillations are decoupled from conventional relaxation oscillations of the carrier-photon system and can be much faster than these. Utilizing these polarization oscillations is thus a very promising approach to develop ultrafast spin-VCSELs for high speed optical data communication in the near future. Different aspects of the spin and polarization dynamics, its connection to birefringence and bistability in the cavity, controlled switching of the oscillations, and the limitations of this novel approach will be analysed theoretically and experimentally for spin-polarized VCSELs at room temperature.

  1. Thermal and optical bleaching of radiation effects in silver activated metaphosphate glass - its use in U.V. dosimetry

    International Nuclear Information System (INIS)

    Nagpal, J.S.; Ramanathan, G.; Gangadharan, P.

    1976-01-01

    While investigating the use of silver activated metaphosphate glass in radiation dosimetry, using its properties of radiophotoluminescence (RPL) in the range 20 mR to 10 3 R and of optical absorbance changes at higher exposures, a difference in the behaviour of the centers responsible for the two phenomenon was observed when the glass was exposed to 253.7 nm u.v. Ultraviolet exposure was observed to bleach the radiophotoluminescence in an irradiated glass whereas it was observed to induce photoluminescence in an unirradiated glass. Thermal behaviour of the two centers was also different. After heating the glass for 5 min at a number of temperatures, a gradual increase in RPL was observed up to 200 0 C. Above 200 0 C, the thermal treatment bleached the RPL. The optical absorbance was bleached from room temperature upwards. (U.K.)

  2. 177Lu-Dendrimer Conjugated to Folate and Bombesin with Gold Nanoparticles in the Dendritic Cavity: A Potential Theranostic Radiopharmaceutical

    Directory of Open Access Journals (Sweden)

    Héctor Mendoza-Nava

    2016-01-01

    Full Text Available 177Lu-labeled nanoparticles conjugated to biomolecules have been proposed as a new class of theranostic radiopharmaceuticals. The aim of this research was to synthesize 177Lu-dendrimer(PAMAM-G4-folate-bombesin with gold nanoparticles (AuNPs in the dendritic cavity and to evaluate the radiopharmaceutical potential for targeted radiotherapy and the simultaneous detection of folate receptors (FRs and gastrin-releasing peptide receptors (GRPRs overexpressed in breast cancer cells. p-SCN-Benzyl-DOTA was conjugated in aqueous-basic medium to the dendrimer. The carboxylate groups of Lys1Lys3(DOTA-bombesin and folic acid were activated with HATU and also conjugated to the dendrimer. The conjugate was mixed with 1% HAuCl4 followed by the addition of NaBH4 and purified by ultrafiltration. Elemental analysis (EDS, particle size distribution (DLS, TEM analysis, UV-Vis, and infrared and fluorescence spectroscopies were performed. The conjugate was radiolabeled using 177LuCl3 or 68GaCl3 and analyzed by radio-HPLC. Studies confirmed the dendrimer functionalization with high radiochemical purity (>95%. Fluorescence results demonstrated that the presence of AuNPs in the dendritic cavity confers useful photophysical properties to the radiopharmaceutical for optical imaging. Preliminary binding studies in T47D breast cancer cells showed a specific cell uptake (41.15±2.72%. 177Lu-dendrimer(AuNP-folate-bombesin may be useful as an optical and nuclear imaging agent for breast tumors overexpressing GRPR and FRs, as well as for targeted radiotherapy.

  3. The “UV-route” to Search for Blue Straggler Stars in Globular Clusters: First Results from the HST UV Legacy Survey

    Energy Technology Data Exchange (ETDEWEB)

    Raso, S.; Ferraro, F. R.; Lanzoni, B. [Department of Physics and Astronomy, University of Bologna, Viale Berti Pichat, 6/2, Bologna (Italy); Dalessandro, E. [INAF Osservatorio Astronomico di Bologna, Via Ranzani 1, Bologna (Italy); Nardiello, D. [Department of Physics and Astronomy Galileo Galilei, University of Padova, Vicolo dell’Osservatorio 3, I-35122 Padova (Italy); Bellini, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Vesperini, E. [Department of Astronomy, Indiana University, Bloomington, IN, 47401 (United States)

    2017-04-10

    We used data from the Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters to select the Blue Straggler Star (BSS) population in four intermediate/high density systems (namely NGC 2808, NGC 6388, NGC 6541, and NGC 7078) through a “UV-guided search.” This procedure consists of using the F275W images in each cluster to construct the master list of detected sources, and then force it to the images acquired in the other filters. Such an approach optimizes the detection of relatively hot stars and allows the detection of a complete sample of BSSs even in the central region of high-density clusters, because the light from the bright cool giants, which dominates the optical emission in old stellar systems, is sensibly reduced at UV wavelengths. Our UV-guided selections of BSSs have been compared to the samples obtained in previous, optical-driven surveys, clearly demonstrating the efficiency of the UV approach. In each cluster we also measured the parameter A {sup +}, defined as the area enclosed between the cumulative radial distribution of BSSs and that of a reference population, which traces the level of BSS central segregation and the level of dynamical evolution suffered by the system. The values measured for the four clusters studied in this paper nicely fall along the dynamical sequence recently presented for a sample of 25 clusters.

  4. Cavity enhanced interference of orthogonal modes in a birefringent medium

    Science.gov (United States)

    Kolluru, Kiran; Saha, Sudipta; Gupta, S. Dutta

    2018-03-01

    Interference of orthogonal modes in a birefringent crystal mediated by a rotator is known to lead to interesting physical effects (Solli et al., 2003). In this paper we show that additional feedback offered by a Fabry-Perot cavity (containing the birefringent crystal and the rotator) can lead to a novel strong interaction regime. Usual signatures of the strong interaction regime like the normal mode splitting and avoided crossings, sensitive to the rotator orientation, are reported. A high finesse cavity is shown to offer an optical setup for measuring small angles. The results are based on direct calculations of the cavity transmissions along with an analysis of its dispersion relation.

  5. Investigation of vacuum deposited hybrid coatings of protic organic UV absorbers embedded in a silica matrix used for the UV protection of Polycarbonate glazing

    OpenAIRE

    Weber, C.; Schulz, U.; Mühlig, C.; Kaiser, N.; Tünnermann, A.

    2016-01-01

    A study of vacuum-deposited organic-inorganic hybrid coatings for UV protection of polycarbonate is presented. UV-absorbing compounds, which are commonly used for polycarbonate, were embedded in a silica matrix by thermal co-evaporation under high vacuum. In addition to the optical properties of the coatings, the influence of the silica network on the organic UV absorber and the stability of the intramolecular hydrogen bond (IMHB) are discussed. A model is presented to show the interaction be...

  6. Effect of External Optical Feedback for Nano-laser Structures

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug

    2013-01-01

    We theoretically investigated the effect of optical feedback on a photonic crystal nanolaser, comparing with conventional in-plane and vertical-cavity lasers.......We theoretically investigated the effect of optical feedback on a photonic crystal nanolaser, comparing with conventional in-plane and vertical-cavity lasers....

  7. A single-frequency, ring cavity Tm-doped fiber laser based on a CMFBG filter

    International Nuclear Information System (INIS)

    Li, Qi; Yan, Fengping; Peng, Wanjing; Liu, Shuo; Feng, Ting; Tan, Siyu; Liu, Peng

    2013-01-01

    A single-frequency (SF), continuous-wave (CW), ring cavity Tm-doped fiber laser has been proposed and demonstrated. A chirped moiré fiber grating (CMFBG) was used as an ultra-narrow filter in the laser cavity to ensure SF operation. When the launched pump power was fixed at 2 W, this proposed laser was in stable operation with a central wavelength, optical signal-to-noise ratio, and full width at half maximum of 1942.8140 nm, 47 dB, and 0.0522 nm, respectively, with a resolution of 0.05 nm. The maximum output power of this laser is 95 mW, a higher output power is restricted by the optical circulator that is used in the cavity. The SF operation of this laser was confirmed by the self-homodyne method. To the best of the authors’ knowledge, this is the first report on an SF, CW, ring cavity Tm-doped fiber laser with a CMFBG filter. (letter)

  8. High-Q silicon-on-insulator slot photonic crystal cavity infiltrated by a liquid

    International Nuclear Information System (INIS)

    Caër, Charles; Le Roux, Xavier; Cassan, Eric

    2013-01-01

    We report the experimental realization of a high-Q slot photonic crystal cavity in Silicon-On-Insulator (SOI) configuration infiltrated by a liquid. Loaded Q-factor of 23 000 is measured at telecom wavelength. The intrinsic quality factor inferred from the transmission spectrum is higher than 200 000, which represents a record value for slot photonic crystal cavities on SOI, whereas the maximum of intensity of the cavity is roughly equal to 20% of the light transmitted in the waveguide. This result makes filled slot photonic crystal cavities very promising for silicon-based light emission and ultrafast nonlinear optics

  9. High-Q Fabry–Pérot Micro-Cavities for High-Sensitivity Volume Refractometry

    Directory of Open Access Journals (Sweden)

    Noha Gaber

    2018-01-01

    Full Text Available This work reports a novel structure for a Fabry–Pérot micro cavity that combines the highest reported quality factor for an on-chip Fabry–Pérot resonator that exceeds 9800, and a very high sensitivity for an on-chip volume refractometer based on a Fabry–Pérot cavity that is about 1000 nm/refractive index unit (RIU. The structure consists of two cylindrical Bragg micromirrors that achieve confinement of the Gaussian beam in the plan parallel to the chip substrate, while for the perpendicular plan, external fiber rod lenses (FRLs are placed in the optical path of the input and the output of the cavity. This novel structure overcomes number of the drawbacks presented in previous designs. The analyte is passed between the mirrors, enabling its detection from the resonance peak wavelengths of the transmission spectra. Mixtures of ethanol and deionized (DI-water with different ratios are used as analytes with different refractive indices to exploit the device as a micro-opto-fluidic refractometer. The design criteria are detailed and the modeling is based on Gaussian-optics equations, which depicts a scenario closer to reality than the usually used ray-optics modeling.

  10. Regularized quasinormal modes for plasmonic resonators and open cavities

    Science.gov (United States)

    Kamandar Dezfouli, Mohsen; Hughes, Stephen

    2018-03-01

    Optical mode theory and analysis of open cavities and plasmonic particles is an essential component of optical resonator physics, offering considerable insight and efficiency for connecting to classical and quantum optical properties such as the Purcell effect. However, obtaining the dissipative modes in normalized form for arbitrarily shaped open-cavity systems is notoriously difficult, often involving complex spatial integrations, even after performing the necessary full space solutions to Maxwell's equations. The formal solutions are termed quasinormal modes, which are known to diverge in space, and additional techniques are frequently required to obtain more accurate field representations in the far field. In this work, we introduce a finite-difference time-domain technique that can be used to obtain normalized quasinormal modes using a simple dipole-excitation source, and an inverse Green function technique, in real frequency space, without having to perform any spatial integrations. Moreover, we show how these modes are naturally regularized to ensure the correct field decay behavior in the far field, and thus can be used at any position within and outside the resonator. We term these modes "regularized quasinormal modes" and show the reliability and generality of the theory by studying the generalized Purcell factor of dipole emitters near metallic nanoresonators, hybrid devices with metal nanoparticles coupled to dielectric waveguides, as well as coupled cavity-waveguides in photonic crystals slabs. We also directly compare our results with full-dipole simulations of Maxwell's equations without any approximations, and show excellent agreement.

  11. Tunable-Range, Photon-Mediated Atomic Interactions in Multimode Cavity QED

    Directory of Open Access Journals (Sweden)

    Varun D. Vaidya

    2018-01-01

    Full Text Available Optical cavity QED provides a platform with which to explore quantum many-body physics in driven-dissipative systems. Single-mode cavities provide strong, infinite-range photon-mediated interactions among intracavity atoms. However, these global all-to-all couplings are limiting from the perspective of exploring quantum many-body physics beyond the mean-field approximation. The present work demonstrates that local couplings can be created using multimode cavity QED. This is established through measurements of the threshold of a superradiant, self-organization phase transition versus atomic position. Specifically, we experimentally show that the interference of near-degenerate cavity modes leads to both a strong and tunable-range interaction between Bose-Einstein condensates (BECs trapped within the cavity. We exploit the symmetry of a confocal cavity to measure the interaction between real BECs and their virtual images without unwanted contributions arising from the merger of real BECs. Atom-atom coupling may be tuned from short range to long range. This capability paves the way toward future explorations of exotic, strongly correlated systems such as quantum liquid crystals and driven-dissipative spin glasses.

  12. Flexible nanomembrane photonic-crystal cavities for tensilely strained-germanium light emission

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Jian; Wang, Xiaowei; Paiella, Roberto [Department of Electrical and Computer Engineering and Photonics Center, Boston University, 8 Saint Mary' s Street, Boston, Massachusetts 02215 (United States); Cui, Xiaorui; Sookchoo, Pornsatit; Lagally, Max G. [Department of Materials Science and Engineering, University of Wisconsin – Madison, 1509 University Avenue, Madison, Wisconsin 53706 (United States)

    2016-06-13

    Flexible photonic-crystal cavities in the form of Si-column arrays embedded in polymeric films are developed on Ge nanomembranes using direct membrane assembly. The resulting devices can sustain large biaxial tensile strain under mechanical stress, as a way to enhance the Ge radiative efficiency. Pronounced emission peaks associated with photonic-crystal cavity resonances are observed in photoluminescence measurements. These results show that ultrathin nanomembrane active layers can be effectively coupled to an optical cavity, while still preserving their mechanical flexibility. Thus, they are promising for the development of strain-enabled Ge lasers, and more generally uniquely flexible optoelectronic devices.

  13. Surface wave resonance and chirality in a tubular cavity with metasurface design

    Science.gov (United States)

    Qin, Yuzhou; Fang, Yangfu; Wang, Lu; Tang, Shiwei; Sun, Shulin; Liu, Zhaowei; Mei, Yongfeng

    2018-06-01

    Optical microcavities with whispering-gallery modes (WGMs) have been indispensable in both photonic researches and applications. Besides, metasurfaces, have attracted much attention recently due to their strong abilities to manipulate electromagnetic waves. Here, combining these two optical elements together, we show a tubular cavity can convert input propagating cylindrical waves into directed localized surface waves (SWs), enabling the circulating like WGMs along the wall surface of the designed tubular cavity. Finite element method (FEM) simulations demonstrate that such near-field WGM shows both large chirality and high local field. This work may stimulate interesting potential applications in e.g. directional emission, sensing, and lasing.

  14. Spontaneous Resolution of Optic Disc Pit Maculopathy

    OpenAIRE

    Tripathy, Koushik

    2017-01-01

    I read with interest the article reporting spontaneous resolution of optic disc pit maculopathy in a boy.1 Though the presence of an optic disc pit and associated macular involvement is undoubted in the presented case, the provided optical coherence tomography (OCT) does not clearly show typical intraretinal schisis (Figure 1B)1 at multiple retinal levels which may communicate with the pit. Instead, it shows a sub-internal limiting membrane (sub-ILM) cavity. Such cavities are known to occur f...

  15. Status report on the development of a high-power UV/IR FEL at CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.; Bohn, C.; Dylla, H.F. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)] [and others

    1995-12-31

    Last year we presented a design for a kilowatt industrial UV FEL based on a superconducting RF accelerator delivering 5 mA of electron-beam current at 200 MeV with energy recovery to enhance efficiency. Since then, we have progressed toward resolving several issues associated with that design. More exact simulations of the injector have resulted in a more accurate estimate of the injector performance. A new injection method has reduced the longitudinal and transverse emittance at the linac entrance. A more compact lattice has been designed for the UV FEL, and a new recirculation scheme has been identified which greatly increases the threshold for longitudinal instabilities. We decided to use a wiggler from the Advanced Photon Source which leads to a robust high-gain FEL. Analysis of the stability of an RF control system based on CEBAF control modules indicates that only minor modifications will be needed to apply them to this FEL. Detailed magnet specifications, vacuum-chamber beam apertures, and diagnostic specifications have been developed for the recirculation arcs. The design of the optical cavity has been conceptualized, and control systems have been devised to regulate mirror distortion. A half-scale model of one of the end-corner cubes has been built and tested. Finally, three-dimensional simulations have been carried out which indicate that the FEL should exceed its minimum design goals with adequate performance margin.

  16. Light-emitting Ga-oxide nanocrystals in glass: a new paradigm for low-cost and robust UV-to-visible solar-blind converters and UV emitters.

    Science.gov (United States)

    Sigaev, Vladimir N; Golubev, Nikita V; Ignat'eva, Elena S; Paleari, Alberto; Lorenzi, Roberto

    2014-01-01

    Wide-bandgap nanocrystals are an inexhaustible source of tuneable functions potentially addressing most of the demand for new light emitting systems. However, the implementation of nanocrystal properties in real devices is not straightforward if a robust and stable optical component is required as a final result. The achievement of efficient light emission from dense dispersions of Ga-oxide nanocrystals in UV-grade glass can be a breakthrough in this regard. Such a result would permit the fabrication of low cost UV-to-visible converters for monitoring UV-emitting events on a large-scale - from invisible hydrogen flames to corona dispersions. From this perspective, γ-Ga₂O₃ nanocrystals are developed by phase separation in Ga-alkali-germanosilicate glasses, obtaining optical materials based on a UV transparent matrix. Band-to-band UV-excitation of light emission from donor-acceptor pair (DAP) recombination is investigated for the first time in embedded γ-Ga₂O₃. The analysis of the decay kinetics gives unprecedented evidence that nanosized confinement of DAP recombination can force a nanophase to the efficient response of exactly balanced DAPs. The results, including a proof of concept of UV-to-visible viewer, definitely demonstrate the feasibility of workable glass-based fully inorganic nanostructured materials with emission properties borrowed from Ga₂O₃ single-crystals and tailored by the nanocrystal size.

  17. Quantum Computation by Optically Coupled Steady Atoms/Quantum-Dots Inside a Quantum Cavity

    Science.gov (United States)

    Pradhan, P.; Wang, K. L.; Roychowdhury, V. P.; Anantram, M. P.; Mor, T.; Saini, Subhash (Technical Monitor)

    1999-01-01

    We present a model for quantum computation using $n$ steady 3-level atoms kept inside a quantum cavity, or using $n$ quantum-dots (QDs) kept inside a quantum cavity. In this model one external laser is pointed towards all the atoms/QDs, and $n$ pairs of electrodes are addressing the atoms/QDs, so that each atom is addressed by one pair. The energy levels of each atom/QD are controlled by an external Stark field given to the atom/QD by its external pair of electrodes. Transition between two energy levels of an individual atom/ QD are controlled by the voltage on its electrodes, and by the external laser. Interactions between two atoms/ QDs are performed with the additional help of the cavity mode (using on-resonance condition). Laser frequency, cavity frequency, and energy levels are far off-resonance most of the time, and they are brought to the resonance (using the Stark effect) only at the time of operations. Steps for a controlled-NOT gate between any two atoms/QDs have been described for this model. Our model demands some challenging technological efforts, such as manufacturing single-electron QDs inside a cavity. However, it promises big advantages over other existing models which are currently implemented, and might enable a much easier scale-up, to compute with many more qubits.

  18. Laguerre-Gauss beam generation in IR and UV by subwavelength surface-relief gratings

    DEFF Research Database (Denmark)

    Vertchenko, Larissa; Shkondin, Evgeniy; Malureanu, Radu

    2017-01-01

    layerdepositions and dry etch techniques. We exploit the phenomenon of formbirefringence to give rise to the spin-to-orbital angular momentum conversion.We demonstrate that these plates can generate beams with high quality for theUV and IR range, allowing them to interact with high power laser sources orinside...... laser cavities....

  19. Fibre Coupled Photonic Crystal Cavity Arrays on Transparent Substrates for Spatially Resolved Sensing

    Directory of Open Access Journals (Sweden)

    Mark G. Scullion

    2014-11-01

    Full Text Available We introduce a photonic crystal cavity array realised in a silicon thin film and placed on polydimethlysiloxane (PDMS as a new platform for the in-situ sensing of biomedical processes. Using tapered optical fibres, we show that multiple independent cavities within the same waveguide can be excited and their resonance wavelength determined from camera images without the need for a spectrometer. The cavity array platform combines sensing as a function of location with sensing as a function of time.

  20. Applied optics

    International Nuclear Information System (INIS)

    Orszag, A.; Antonetti, A.

    1988-01-01

    The 1988 progress report, of the Applied Optics laboratory, of the (Polytechnic School, France), is presented. The optical fiber activities are focused on the development of an optical gyrometer, containing a resonance cavity. The following domains are included, in the research program: the infrared laser physics, the laser sources, the semiconductor physics, the multiple-photon ionization and the nonlinear optics. Investigations on the biomedical, the biological and biophysical domains are carried out. The published papers and the congress communications are listed [fr

  1. Superconducting Qubit Optical Transducer (SQOT)

    Science.gov (United States)

    2015-08-05

    parts on optical signals and any quasiparticle loss caused by optical photons on microwave signals. Using a superconducting 3D cavity as the microwave...plasmonic and quasiparticle losses. 3. The electro-optic material should be easily integrable with superconducting circuits. A fully integrated

  2. Dynamics of an atomic wave packet in a standing-wave cavity field: A cavity-assisted single-atom detection

    International Nuclear Information System (INIS)

    Chough, Young-Tak; Nha, Hyunchul; Kim, Sang Wook; An, Kyungwon; Youn, Sun-Hyun

    2002-01-01

    We investigate the single-atom detection system using an optical standing-wave cavity, from the viewpoint of the quantized center-of-mass motion of the atomic wave packet. We show that since the atom-field coupling strength depends upon the overlap integral of the atomic wave packet and the field mode function, the effect of the wave-packet spreading via the momentum exchange process brings about a significant effect in the detection efficiency. We find that, as a result, the detection efficiency is not sensitive to the individual atomic trajectory for reasonably slow atoms. We also address an interesting phenomenon of the atomic wave-packet splitting occurring when an atom passes through a node of the cavity field

  3. Investigation of the use of FXG gel dosimeter for UV radiation detection

    International Nuclear Information System (INIS)

    Bero, M.; Abu Kassem, I.

    2009-02-01

    The radio-chromic chemical radiation dosimeter is well known type of detectors that have been used in the measurement application of radiation dose resulting for ionizing radiation such as γ and X-rays. The detector materials consist of mainly water with added gelatin powder that gives the detector its solid shape. Other chemicals sensitive to radiation are also added to form the Ferrous-sulfate Xylenol-orange Gelatin gel detector (FXG). Ionizing radiation effects appears as an increase in the optical absorbance within a defined range of wavelengths located in the visible region of the light spectrum. These visible changes in the materials optical characteristic as a result of radiation exposure is proportional to the radiation absorbed dose at certain wave lengths. Ultraviolet radiation was found to produce similar effects in the FXG detector materials; hence we suggested studying the UV effects in details. It is known that UV radiation carry relatively high quantum energies big enough to enhance important chemical and biological reactions in some exposed medium. This study examines the most important properties required for the FXG detector to be used as a UV monitoring system that is capable of measuring the absorbed UV radiation dose. The study also works on finding chemical detector structure that is easy to be used for simulating the UV interactions with human body. It has been shown that the optical absorbance of standard size FXG samples increases linearly with the exposure time to UV radiation produced by a sun simulator source, when the beam is filtered to produces exposure similar to that found in nature. However, the UV effects are also influenced by the applied UV radiation spectrum used for irradiation as well as the thicknesses of the FXG materials.(authors)

  4. Optical properties of cadmium sulfide nanocrystal film prepared by electrochemical synthesis at liquid-liquid interface

    International Nuclear Information System (INIS)

    Luan Yemei; An Maozhong; Lu Guoqi

    2006-01-01

    Dendritic nanocrystalline CdS film was deposited at liquid-liquid interface of surfactants and an electrolyte containing 4 mmol L -1 cadmium chloride (CdCl 2 ) and 16 mmol L -1 thioacetamide (CH 3 CSNH 2 ) with an initial pH value of 5 at 15 deg. C by electrochemical synthesis. The nanofilm was characterized by transmission electron microscopy (TEM), field emission scanning electron microscope (FE-SEM), atomic force microscopy (AFM), ultraviolet visible (UV-vis) absorption spectroscopy and fluorescence spectroscopy. The surface morphology and particle size of the nanofilm were investigated by AFM, SEM and TEM, and the crystalline size was 30-50 nm. The thickness of the nanofilm calculated by optical absorption spectrum was 80 nm. The microstructure and composition of the nanofilm was investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), showing its polycrystalline structure consisting of CdS and Cd. Optical properties of the nanofilm were investigated systematically by UV-vis absorption and fluorescence spectroscopy. A λ onset blue shift compared with bulk CdS was observed in the absorption spectra. Fluorescence spectra of the nanofilm indicated that the CdS nanofilm emitted blue and green light. The nanocomposites film electrode will bring about anodic photocurrent during illumination, showing that the transfer of cavities produces photocurrent

  5. Use of UV absorption for identifying subspecies of Artemisia tridentata

    International Nuclear Information System (INIS)

    Spomer, G.G.; Henderson, D.M.

    1988-01-01

    Use of UV absorption spectra for identifying subspecies of Artemisia tridentata Nutt. was investigated by analyzing the relative optical densities of alcohol extracts from herbarium and fresh plant material at 240 nm, 250 nm, and 265 nm. In all but 1 comparison, mean relative optical densities were significantly different (p=0.95) between subspecies, but intraplant and intrasubspecies variation and overlap was found to be too large to permit use of UV absorbance alone for identifying individual specimens. These results held whether dry or fresh leaves were extracted, or whether methanol or ethanol was used as the extracting solvent. (author)

  6. Cavity Opto-Mechanics using an Optically Levitated Nanosphere

    Science.gov (United States)

    2010-01-19

    center-of-mass motion of a levitated nanosphere. entanglement ∣ optical levitation ∣ quantum information One of the most intriguing questions associated...developed. Outlook An optically levitated opto-mechanical system can have remark- ably long coherence times, which potentially enables quantum phenomena...47) or facilitate novel quantum hybrid architectures (6). Note added: We have become aware of a recent, similar proposal to optically levitate and

  7. The Origins of UV-optical Color Gradients in Star-forming Galaxies at z ˜ 2: Predominant Dust Gradients but Negligible sSFR Gradients

    Science.gov (United States)

    Liu, F. S.; Jiang, Dongfei; Faber, S. M.; Koo, David C.; Yesuf, Hassen M.; Tacchella, Sandro; Mao, Shude; Wang, Weichen; Guo, Yicheng; Fang, Jerome J.; Barro, Guillermo; Zheng, Xianzhong; Jia, Meng; Tong, Wei; Liu, Lu; Meng, Xianmin

    2017-07-01

    The rest-frame UV-optical (I.e., NUV - B) color is sensitive to both low-level recent star formation (specific star formation rate—sSFR) and dust. In this Letter, we extend our previous work on the origins of NUV - B color gradients in star-forming galaxies (SFGs) at z˜ 1 to those at z˜ 2. We use a sample of 1335 large (semimajor axis radius {R}{SMA}> 0\\buildrel{\\prime\\prime}\\over{.} 18) SFGs with extended UV emission out to 2{R}{SMA} in the mass range {M}* ={10}9{--}{10}11 {M}⊙ at 1.5negative NUV - B color gradients (redder centers), and their color gradients strongly increase with galaxy mass. We also show that the global rest-frame FUV - NUV color is approximately linear with {A}{{V}}, which is derived by modeling the observed integrated FUV to NIR spectral energy distributions of the galaxies. Applying this integrated calibration to our spatially resolved data, we find a negative dust gradient (more dust extinguished in the centers), which steadily becomes steeper with galaxy mass. We further find that the NUV - B color gradients become nearly zero after correcting for dust gradients regardless of galaxy mass. This indicates that the sSFR gradients are negligible and dust reddening is likely the principal cause of negative UV-optical color gradients in these SFGs. Our findings support that the buildup of the stellar mass in SFGs at Cosmic Noon is self-similar inside 2{R}{SMA}.

  8. Organic conjugated small molecule materials based optical probe for rapid, colorimetric and UV-vis spectral detection of phosphorylated protein in placental tissue.

    Science.gov (United States)

    Wang, Yanfang; Yang, Na; Liu, Yi

    2018-04-05

    A novel organic small molecule with D-Pi-A structure was prepared, which was found to be a promising colorimetric and ratiometric UV-vis spetral probe for detection of phosphorylated proteins with the help of tetravalent zirconium ion. Such optical probe based on chromophore WYF-1 shows a rapid response (within 10s) and high selectivity and sensitivity for phosphorylated proteins, giving distinct colorimetric and ratiometric UV-vis changes at 720 and 560nm. The detection limit for phosphorylated proteins was estimated to be 100nM. In addition, detection of phosphorylated proteins in placental tissue samples with this probe was successfully applied, which indicates that this probe holds great potential for phosphorylated proteins detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Challenges in resonant cavity biosensor design: collection efficiency and specificity

    Science.gov (United States)

    Armani, Andrea M.; Mehrabani, Simin; Sun, Victoria; McBirney, Samantha; Hawk, Rasheeda M.; Gungor, Eda; Lee, Michele

    2014-03-01

    Optical cavities have successfully demonstrated the ability to detect a wide range of analytes with exquisite sensitivity. However, optimizing other parameters of the system, such as collection efficiency and specificity, have remained elusive. This presentation will discuss some of the recent work in this area, including 3D COMSOL Multiphysics models including mass transfer and binding kinetics of different cavity geometries and covalent attachment methods for a wide range of biological and synthetic moieties. A few representative experimental demonstrations will also be presented.

  10. Ultra-wide frequency response measurement of an optical system with a DC photo-detector

    KAUST Repository

    Kuntz, Katanya B.

    2017-01-09

    Precise knowledge of an optical device\\'s frequency response is crucial for it to be useful in most applications. Traditional methods for determining the frequency response of an optical system (e.g. optical cavity or waveguide modulator) usually rely on calibrated broadband photo-detectors or complicated RF mixdown operations. As the bandwidths of these devices continue to increase, there is a growing need for a characterization method that does not have bandwidth limitations, or require a previously calibrated device. We demonstrate a new calibration technique on an optical system (consisting of an optical cavity and a high-speed waveguide modulator) that is free from limitations imposed by detector bandwidth, and does not require a calibrated photo-detector or modulator. We use a low-frequency (DC) photo-detector to monitor the cavity\\'s optical response as a function of modulation frequency, which is also used to determine the modulator\\'s frequency response. Knowledge of the frequency-dependent modulation depth allows us to more precisely determine the cavity\\'s characteristics (free spectral range and linewidth). The precision and repeatability of our technique is demonstrated by measuring the different resonant frequencies of orthogonal polarization cavity modes caused by the presence of a non-linear crystal. Once the modulator has been characterized using this simple method, the frequency response of any passive optical element can be determined to a fine resolution (e.g. kilohertz) over several gigahertz.

  11. The Development of Cavity Ringdown Spectroscopy as a Toxic Metal Continuous Emission Monitor

    International Nuclear Information System (INIS)

    Miller, Goeroge P.; Winstead, Christopher B.

    2001-01-01

    Innovative program to explore the viability of using Cavity Ringdown Spectroscopy (CRDS) for trace analysis and monitoring of remediation processes for hazardous and radioactive wastes. Cavity ringdown spectroscopy is a measurement of the rate of absorption of a sample within a closed optical cavity rather than the standard measurement of the absorbed signal strength over a given sample path. It is a technique capable of providing ultra-sensitive absorption measurements in hostile environments using commercially available easy-to-use pulsed lasers. The inherent high sensitivity stems from both the long effective sample pathlengths possible and the relaxed constraints on the accuracy of the measurement of the cavity decay time

  12. Single-nanoparticle detection with slot-mode photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cheng; Kita, Shota; Lončar, Marko, E-mail: loncar@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Li, Yihang [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

    2015-06-29

    Optical cavities that are capable for detecting single nanoparticles could lead to great progress in early stage disease diagnostics and the study of biological interactions on the single-molecule level. In particular, photonic crystal (PhC) cavities are excellent platforms for label-free single-nanoparticle detection, owing to their high quality (Q) factors and wavelength-scale modal volumes. Here, we demonstrate the design and fabrication of a high-Q (>10{sup 4}) slot-mode PhC nanobeam cavity, which is able to strongly confine light in the slotted regions. The enhanced light-matter interaction results in an order of magnitude improvement in both refractive index sensitivity (439 nm/RIU) and single-nanoparticle sensitivity compared with conventional dielectric-mode PhC cavities. Detection of single polystyrene nanoparticles with radii of 20 nm and 30 nm is demonstrated in aqueous environments (D{sub 2}O), without additional laser and temperature stabilization techniques.

  13. Enhancement of Rayleigh scatter in optical fiber by simple UV treatment: an order of magnitude increase in distributed sensing sensitivity

    Science.gov (United States)

    Loranger, Sébastien; Parent, François; Lambin-Iezzi, Victor; Kashyap, Raman

    2016-02-01

    Rayleigh scatter in optical fiber communication systems has long been considered a nuisance as a loss mechanism, although applications have used such scatter to probe the fiber for faults and propagation loss using time domain reflectometry (OTDR). It is however only with the development of Frequency domain reflectometry (OFDR) and coherent-phase OTDR that Rayleigh scatter has been probed to its deepest and can now be used to measure strain and temperature along a fiber, leading to the first distributed sensing applications. However, Rayleigh scatter remains very weak giving rise to very small signals which limits the technique for sensing. We show here a new technique to significantly enhance the Rayleigh scatter signal by at least two orders of magnitude, in a standard optical fiber with simple UV exposure of the core. A study of various exposures with different types of fibers has been conducted and a phenomenological description developed. We demonstrate that such an increase in signal can enhance the temperature and strain sensitivity by an order of magnitude for distributed sensing with an OFDR technique. Such improved performance can lead to temperature/strain RMS noise levels of 6 mK and 50 nɛ for 1 cm spatial resolution in UV exposed SMF-28, compared to the typical noise level of 100 mK for the same spatial resolution in the similar unexposed fiber.

  14. Semiconductor quantum optics with tailored photonic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Laucht, Arne

    2011-06-15

    This thesis describes detailed investigations of the effects of photonic nanostructures on the light emission properties of self-assembled InGaAs quantum dots. Nanoscale optical cavities and waveguides are employed to enhance the interaction between light and matter, i.e. photons and excitons, up to the point where optical non-linearities appear at the quantum (single photon) level. Such non-linearities are an essential component for the realization of hardware for photon based quantum computing since they can be used for the creation and detection of non-classical states of light and may open the way to new genres of quantum optoelectronic devices such as optical modulators and optical transistors. For single semiconductor quantum dots in photonic crystal nanocavities we investigate the coupling between excitonic transitions and the highly localized mode of the optical cavity. We explore the non-resonant coupling mechanisms which allow excitons to couple to the cavity mode, even when they are not spectrally in resonance. This effect is not observed for atomic cavity quantum electrodynamics experiments and its origin is traced to phonon-assisted scattering for small detunings ({delta}E<{proportional_to}5 meV) and a multi-exciton-based, Auger-like process for larger detunings ({delta}E >{proportional_to}5 meV). For quantum dots in high-Q cavities we observe the coherent coupling between exciton and cavity mode in the strong coupling regime of light-matter interaction, probe the influence of pure dephasing on the coherent interaction at high excitation levels and high lattice temperatures, and examine the coupling of two spatially separated quantum dots via the exchange of real and virtual photons mediated by the cavity mode. Furthermore, we study the spontaneous emission properties of quantum dots in photonic crystal waveguide structures, estimate the fraction of all photons emitted into the propagating waveguide mode, and demonstrate the on-chip generation of

  15. Enhancement and suppression of opto-acoustic parametric interactions using optical feedback

    International Nuclear Information System (INIS)

    Zhang Zhongyang; Zhao Chunnong; Ju, L.; Blair, D. G.

    2010-01-01

    A three mode opto-acoustic parametric amplifier (OAPA) is created when two orthogonal optical modes in a high finesse optical cavity are coupled via an acoustic mode of the cavity mirror. Such interactions are predicted to occur in advanced long baseline gravitational wave detectors. They can have high positive gain, which leads to strong parametric instability. Here we show that an optical feedback scheme can enhance or suppress the parametric gain of an OAPA, allowing exploration of three-mode parametric interactions, especially in cavity systems that have insufficient optical power to achieve spontaneous instability. We derive analytical equations and show that optical feedback is capable of controlling predicted instabilities in advanced gravitational wave detectors within a time scale of 13∼10 s.

  16. Development of highly qualified UV-laser light source for rf gun

    International Nuclear Information System (INIS)

    Tomizawa, H.; Dewa, H.; Taniuchi, T.

    2004-01-01

    We have been developing stable and highly qualified UV-laser pulse as a light source of the rf gun for an injector candidate of future light sources. Our gun cavity is a single-cell pillbox, and the copper inner wall is used as a photo cathode. In present status, the short pulse energy stability of laser has been improved down to 1.3∼1.5% (rms; 10pps; 10000 shots) at the third harmonic generation. The long stability depends on the stability of modelocking at oscillator. In this improvement we just passively stabilized the system. We considered environmental controls in clean room to reduce optical damage accidents and constructed a new humidity-controlled clean room in 2003. And we re-installed the total laser system in this room in 2004. The relative humidity of this new clean room at room temperature is in a region of 50∼60 % with a stability of less than 2% (p-p). On the other hand, the ideal spatial and temporal profiles of a shot-by-shot single laser pulse are essential to suppress the emittance growth of the electron beam from a photo-cathode rf gun. This laser-shaping project has been started in two steps since 2002. As the first successful test run in 2002, with a microlens array as a simple spatial shaper, we obtained a minimum emittance value of 2π mm·mrad with a beam energy of 3.1 MeV, holding its charge to 0.1 nC/bunch. In the next test run in 2004, we prepared a deformable mirror for spatial shaping, and a spatial light modulator based on fused-silica plates for temporal shaping. We are applying the both adaptive optics to automatically shape the both spatial and temporal UV-laser profiles with a feedback routine at the same time. We report herein the principle and developing process of our laser beam quality control system. (author)

  17. Asymmetric light transmission based on coupling between photonic crystal waveguides and L1/L3 cavity

    Science.gov (United States)

    Zhang, Jinqiannan; Chai, Hongyu; Yu, Zhongyuan; Cheng, Xiang; Ye, Han; Liu, Yumin

    2017-09-01

    A compact design of all-optical diode with mode conversion function based on a two-dimensional photonic crystal waveguide and an L1 or L3 cavity is theoretically investigated. The proposed photonic crystal structures comprise a triangular arrangement of air holes embedded in a silicon substrate. Asymmetric light propagation is achieved via the spatial mode match/mismatch in the coupling region. The simulations show that at each cavity's resonance frequency, the transmission efficiency of the structure with the L1 and L3 cavities reach 79% and 73%, while the corresponding unidirectionalities are 46 and 37 dB, respectively. The functional frequency can be controlled by simply adjusting the radii of specific air holes in the L1 and L3 cavities. The proposed structure can be used as a frequency filter, a beam splitter and has potential applications in all-optical integrated circuits.

  18. The combined effect of side-coupled gain cavity and lossy cavity on the plasmonic response of metal-dielectric-metal surface plasmon polariton waveguide

    International Nuclear Information System (INIS)

    Zhu, Qiong-gan; Wang, Zhi-guo; Tan, Wei

    2014-01-01

    The combined effect of side-coupled gain cavity and lossy cavity on the plasmonic response of metal-dielectric-metal (MDM) surface plasmon polariton (SPP) waveguide is investigated theoretically using Green's function method. Our result suggests that the gain and loss parameters influence the amplitude and phase of the fields localized in the two cavities. For the case of balanced gain and loss, the fields of the two cavities are always of equi-amplitude but out of phase. A plasmon induced transparency (PIT)-like transmission peak can be achieved by the destructive interference of two fields with anti-phase. For the case of unbalanced gain and loss, some unexpected responses of structure are generated. When the gain is more than the loss, the system response is dissipative at around the resonant frequency of the two cavities, where the sum of reflectance and transmittance becomes less than one. This is because the lossy cavity, with a stronger localized field, makes the main contribution to the system response. When the gain is less than the loss, the reverse is true. It is found that the metal loss dissipates the system energy but facilitates the gain cavity to make a dominant effect on the system response. This mechanism may have a potential application for optical amplification and for a plasmonic waveguide switch. (paper)

  19. Depth probing of the hydride formation process in thin Pd films by combined electrochemistry and fiber optics-based in situ UV/vis spectroscopy.

    Science.gov (United States)

    Wickman, Björn; Fredriksson, Mattias; Feng, Ligang; Lindahl, Niklas; Hagberg, Johan; Langhammer, Christoph

    2015-07-15

    We demonstrate a flexible combined electrochemistry and fiber optics-based in situ UV/vis spectroscopy setup to gain insight into the depth evolution of electrochemical hydride and oxide formation in Pd films with thicknesses of 20 and 100 nm. The thicknesses of our model systems are chosen such that the films are thinner or significantly thicker than the optical skin depth of Pd to create two distinctly different situations. Low power white light is irradiated on the sample and analyzed in three different configurations; transmittance through, and, reflectance from the front and the back side of the film. The obtained optical sensitivities correspond to fractions of a monolayer of adsorbed or absorbed hydrogen (H) and oxygen (O) on Pd. Moreover, a combined simultaneous readout obtained from the different optical measurement configurations provides mechanistic insights into the depth-evolution of the studied hydrogenation and oxidation processes.

  20. Diagnostics and treatment of 1.3 GHz Nb cavities

    Energy Technology Data Exchange (ETDEWEB)

    Tamashevich, Yegor

    2017-01-15

    increase the accuracy of the measurements. A new program code for quench localisation calculating the path of the second-sound wave was developed. This allows the signals from all sensors to be used, regardless of their position relative to the quench site. The new approach was validated using additional techniques such as a temperature mapping and an optical inspection of the inner cavity surface. Furthermore, a new multi-sensor for second-sound wave detection in the helium vessel of a cavity was developed and successfully tested on a serial-production XFEL cavity. The determined quench site location was confirmed by subsequent optical inspection. The algorithm localises the quench without mode measurements i.e. there is no need to dismount HOM-antennas which requires special procedures and must be performed in a clean-room. The mathematical approach described in this paper can be applied for second-sound tests of superconductive cavities of various shapes and dimensions.

  1. Diagnostics and treatment of 1.3 GHz Nb cavities

    International Nuclear Information System (INIS)

    Tamashevich, Yegor

    2017-01-01

    for quench localisation calculating the path of the second-sound wave was developed. This allows the signals from all sensors to be used, regardless of their position relative to the quench site. The new approach was validated using additional techniques such as a temperature mapping and an optical inspection of the inner cavity surface. Furthermore, a new multi-sensor for second-sound wave detection in the helium vessel of a cavity was developed and successfully tested on a serial-production XFEL cavity. The determined quench site location was confirmed by subsequent optical inspection. The algorithm localises the quench without mode measurements i.e. there is no need to dismount HOM-antennas which requires special procedures and must be performed in a clean-room. The mathematical approach described in this paper can be applied for second-sound tests of superconductive cavities of various shapes and dimensions.

  2. Statistical parity-time-symmetric lasing in an optical fibre network.

    Science.gov (United States)

    Jahromi, Ali K; Hassan, Absar U; Christodoulides, Demetrios N; Abouraddy, Ayman F

    2017-11-07

    Parity-time (PT)-symmetry in optics is a condition whereby the real and imaginary parts of the refractive index across a photonic structure are deliberately balanced. This balance can lead to interesting optical phenomena, such as unidirectional invisibility, loss-induced lasing, single-mode lasing from multimode resonators, and non-reciprocal effects in conjunction with nonlinearities. Because PT-symmetry has been thought of as fragile, experimental realisations to date have been usually restricted to on-chip micro-devices. Here, we demonstrate that certain features of PT-symmetry are sufficiently robust to survive the statistical fluctuations associated with a macroscopic optical cavity. We examine the lasing dynamics in optical fibre-based coupled cavities more than a kilometre in length with balanced gain and loss. Although fluctuations can detune the cavity by more than the free spectral range, the behaviour of the lasing threshold and the laser power is that expected from a PT-stable system. Furthermore, we observe a statistical symmetry breaking upon varying the cavity loss.

  3. Efficient Atomic One-Qubit Phase Gate Realized by a Cavity QED and Identical Atoms System

    International Nuclear Information System (INIS)

    He Yong; Jiang Nianquan

    2010-01-01

    We present a scheme to implement a one-qubit phase gate with a two-level atom crossing an optical cavity in which some identical atoms are trapped. One can conveniently acquire an arbitrary phase shift of the gate by properly choosing the number of atoms trapped in the cavity and the velocity of the atom crossing the cavity. The present scheme provides a very simple and efficient way for implementing one-qubit phase gate. (general)

  4. Cavity-enhanced Faraday rotation measurement with auto-balanced photodetection.

    Science.gov (United States)

    Chang, Chia-Yu; Shy, Jow-Tsong

    2015-10-01

    Optical cavity enhancement for a tiny Faraday rotation is demonstrated with auto-balanced photodetection. This configuration is analyzed using the Jones matrix formalism. The resonant rotation signal is amplified, and thus, the angular sensitivity is improved. In the experiment, the air Faraday rotation is measured with an auto-balanced photoreceiver in single-pass and cavity geometries. The result shows that the measured Faraday rotation in the single-pass geometry is enhanced by a factor of 85 in the cavity geometry, and the sensitivity is improved to 7.54×10(-10)  rad Hz(-1/2), which agrees well with the Jones matrix analysis. With this verification, we propose an AC magnetic sensor whose magnetic sensitivity is expected to achieve 10  pT Hz(-1/2).

  5. Development of a Fabry-Perot cavity for the Compton polarimetry

    International Nuclear Information System (INIS)

    Jorda, Jean-Paul

    1997-01-01

    A quick, precise and non-destructive longitudinal polarisation measurement should be a great advantage for the HAPPEX experiment at CEBAF (Jefferson Lab, USA). To achieve this, it could be possible to use a Fabry-Perot cavity to get a high photon flux at the electron-photon interaction point of a Compton polarimeter. This thesis is a first study for the design of such a system. We have shown that a 'monolithic' cavity, i.e. with mirrors mounted on fixed stage, is a good solution. My contribution for these studies is the development of a code to compute the optimum geometry of a cavity. Another of my contribution concerns the test of a cavity based on commercial mirrors with a gain > 160, using the Pound-Drever method to lock the laser frequency. My studies concern optical matching between the laser beam and the cavity, the choice of the frequency of modulation for the feed-back system and the characterization of the intracavity power. This work is a first step of the studies which will lead to the integration of a cavity based system on the CEBAF beam line. (author) [fr

  6. Frequency splitting of polarization eigenmodes in microscopic Fabry–Perot cavities

    International Nuclear Information System (INIS)

    Uphoff, Manuel; Brekenfeld, Manuel; Rempe, Gerhard; Ritter, Stephan

    2015-01-01

    We study the frequency splitting of the polarization eigenmodes of the fundamental transverse mode in CO 2 laser-machined, high-finesse optical Fabry–Perot cavities and investigate the influence of the geometry of the cavity mirrors. Their highly reflective surfaces are typically not rotationally symmetric but have slightly different radii of curvature along two principal axes. We observe that the eccentricity of such elliptical mirrors lifts the degeneracy of the polarization eigenmodes. The impact of the eccentricity increases for smaller radii of curvature. A model derived from corrections to the paraxial resonator theory is in excellent agreement with the measurements, showing that geometric effects are the main source of the frequency splitting of polarization modes for the type of microscopic cavity studied here. By rotating one of the mirrors around the cavity axis, the splitting can be tuned. In the case of an identical differential phase shift per mirror, it can even be eliminated, despite a nonvanishing eccentricity of each mirror. We expect our results to have important implications for many experiments in cavity quantum electrodynamics, where Fabry–Perot cavities with small mode volumes are required. (paper)

  7. Spectral tuning of optical coupling between air-mode nanobeam cavities and individual carbon nanotubes

    Science.gov (United States)

    Machiya, Hidenori; Uda, Takushi; Ishii, Akihiro; Kato, Yuichiro K.

    Air-mode nanobeam cavities allow for high efficiency coupling to air-suspended carbon nanotubes due to their unique mode profile that has large electric fields in air. Here we utilize heating-induced energy shift of carbon nanotube emission to investigate the cavity quantum electrodynamics effects. In particular, we use laser-induced heating which causes a large blue-shift of the nanotube photoluminescence as the excitation power is increased. Combined with a slight red-shift of the cavity mode at high powers, detuning of nanotube emission from the cavity can be controlled. We estimate the spontaneous emission coupling factor β at different spectral overlaps and find an increase of β factor at small detunings, which is consistent with Purcell enhancement of nanotube emission. Work supported by JSPS (KAKENHI JP26610080, JP16K13613), Asahi Glass Foundation, Canon Foundation, and MEXT (Photon Frontier Network Program, Nanotechnology Platform).

  8. Using the etalon effect for in situ balancing of the Advanced Virgo arm cavities

    International Nuclear Information System (INIS)

    Hild, S; Freise, A; Chelkowski, S; Mantovani, M; Degallaix, J; Schilling, R

    2009-01-01

    Several large-scale interferometric gravitational-wave detectors use resonant arm cavities to enhance the light power in the interferometer arms. These cavities are based on different optical designs: One design uses wedged input mirrors to create additional optical pick-off ports for deriving control signals. The second design employs input mirrors without wedge and thus offers the possibility of using the etalon effect inside the input mirrors for tuning the finesse of the arm cavities. In this paper, we introduce a concept of maximum flexibility that combines both of these options, by featuring wedges at the input mirrors and using the etalon effect instead in the end mirrors. We present a design for the arm cavities of Advanced Virgo. The paper focusses on evaluating the influence of etalon imperfections onto the overall Advanced Virgo performance. We use numerical simulations to derive requirements for the manufacturing accuracy of an end mirror etalon for Advanced Virgo. Furthermore, we give analytical approximations for the achievable tuning range of an imperfect etalon depending on the curvature and orientation mismatch of the two etalon surfaces. We evaluate the displacement noise originating from temperature driven optical phase noise of the etalon. In addition the influence of the etalon effect onto other Advanced Virgo subsystems such as the alignment sensing and control is analysed.

  9. Optical properties of infrared FELs from the FELI Facility II

    Energy Technology Data Exchange (ETDEWEB)

    Saeki, K.; Okuma, S.; Oshita, E. [Free Electron Laser Institute, Osaka (Japan)] [and others

    1995-12-31

    The FELI Facility II has succeeded in infrared FEL oscillation at 1.91 {mu} m using a 68-MeV, 40-A electron beam from the FELI S-band linac in February 27, 1995. The FELI Facility II is composed of a 3-m vertical type undulator ({lambda}u=3.8cm, N=78, Km a x=1.4, gap length {ge}20mm) and a 6.72-m optical cavity. It can cover the wavelength range of 1-5{mu}m. The FELs can be delivered from the optical cavity to the diagnostics room through a 40-m evacuated optical pipeline. Wavelength and cavity length dependences of optical properties such as peak power, average power, spectrum width, FEL macropulse, FEL transverse profile are reported.

  10. Bistable laser device with multiple coupled active vertical-cavity resonators

    Science.gov (United States)

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-08-19

    A new class of bistable coupled-resonator vertical-cavity semiconductor laser devices has been developed. These bistable laser devices can be switched, either electrically or optically, between lasing and non-lasing states. A switching signal with a power of a fraction of a milliwatt can change the laser output of such a device by a factor of a hundred, thereby enabling a range of optical switching and data encoding applications.

  11. A foldable electrode array for 3D recording of deep-seated abnormal brain cavities

    Science.gov (United States)

    Kil, Dries; De Vloo, Philippe; Fierens, Guy; Ceyssens, Frederik; Hunyadi, Borbála; Bertrand, Alexander; Nuttin, Bart; Puers, Robert

    2018-06-01

    Objective. This study describes the design and microfabrication of a foldable thin-film neural implant and investigates its suitability for electrical recording of deep-lying brain cavity walls. Approach. A new type of foldable neural electrode array is presented, which can be inserted through a cannula. The microfabricated electrode is specifically designed for electrical recording of the cavity wall of thalamic lesions resulting from stroke. The proof-of-concept is demonstrated by measurements in rat brain cavities. On implantation, the electrode array unfolds in the brain cavity, contacting the cavity walls and allowing recording at multiple anatomical locations. A three-layer microfabrication process based on UV-lithography and Reactive Ion Etching is described. Electrochemical characterization of the electrode is performed in addition to an in vivo experiment in which the implantation procedure and the unfolding of the electrode are tested and visualized. Main results. Electrochemical characterization validated the suitability of the electrode for in vivo use. CT imaging confirmed the unfolding of the electrode in the brain cavity and analysis of recorded local field potentials showed the ability to record neural signals of biological origin. Significance. The conducted research confirms that it is possible to record neural activity from the inside wall of brain cavities at various anatomical locations after a single implantation procedure. This opens up possibilities towards research of abnormal brain cavities and the clinical conditions associated with them, such as central post-stroke pain.

  12. Raman spectroscopy and single-photon source in an ion-cavity system

    International Nuclear Information System (INIS)

    Goncalves de Barros, H.

    2010-01-01

    The work presented in this thesis explores the interaction between a single trapped 40Ca+ ion and the electromagnetic field inside a high-finesse optical cavity. The coupling takes place via the use of a vacuum stimulated Raman transition, which transfers atomic population from the S1/2 to the D3/2 manifolds of the calcium ion producing a photon in the cavity. This photon is measured and properties of the system are evaluated. Spectroscopy measurements of the Raman transitions are performed and all possible transitions are identified for different polarizations of both drive laser and cavity fields. The system is also used to deterministically produce single photons. Simulation curves quantitatively match the experimental results within calibration error bars. The single-photon creation efficiency obtained in this work overcomes previous ion-cavity setups and is comparable to state-of-the-art systems composed of a neutral atom and a cavity operating in the strong coupling regime. (author)

  13. The UV Sensor Onboard the Mars Science Laboratory Mission: Correction and Generation of UV Fluxes

    Science.gov (United States)

    Vicente-Retortillo, Á.; Martinez, G.; Renno, N. O.; Lemmon, M. T.; Gomez-Elvira, J.

    2017-12-01

    The Rover Environmental Monitoring Station UV sensor (UVS) onboard the Mars Science Laboratory mission has completed more than 1750 sols of measurements, providing an unprecedented coverage ranging from diurnal to interannual times scales [1,2]. The UVS is comprised of six photodiodes to measure the UV flux in the ranges 200-380, 320-380, 280-320, 200-280, 230-290 and 300-350 nm [3]. UV fluxes in units of W/m2 can be found in the NASA Planetary Data System (PDS). However, dust deposition on the UVS and a non-physical discontinuity in the calibration functions when the solar zenith angle is above 30º cause errors in these fluxes that increase with time. We have developed a technique to correct UV fluxes from the effects of dust degradation and inconsistencies in the angular response of the UVS. The photodiode output currents (available in the PDS as lower-level TELRDR products), ancillary data records (available in the PDS as ADR products) and dust opacity values derived from Mastcam observations are used for performing the corrections. The corrections have been applied to the UVA band (320-380 nm) for the first 1000 sols of the mission, providing excellent results [4]. We plan to correct the UV fluxes on each of the six UVS bands and to make these results available in the PDS. Data products generated by this study will allow comparisons of the UV radiation environment at Gale crater with that at the locations of the future missions ExoMars 2020 and Mars 2020, as well as the assessment of the potential survivability of biological contaminants brought to Mars from Earth. References: [1] Smith, M. D., et al. (2016), Aerosol optical depth as observed by the Mars Science Laboratory REMS UV photodiodes, Icarus, 280, 234-248. [2] Vicente-Retortillo, Á., et al. (2017), Determination of dust aerosol particle size at Gale Crater using REMS UVS and Mastcam measurements, Geophys. Res. Lett., 44, 3502-3508. [3] Gómez-Elvira, J., et al. (2012), REMS: The environmental sensor

  14. Tunable single quantum dot nanocavities for cavity QED experiments

    International Nuclear Information System (INIS)

    Kaniber, M; Laucht, A; Neumann, A; Bichler, M; Amann, M-C; Finley, J J

    2008-01-01

    We present cavity quantum electrodynamics experiments performed on single quantum dots embedded in two-dimensional photonic crystal nanocavities. We begin by describing the structural and optical properties of the quantum dot sample and the photonic crystal nanocavities and compare the experimental results with three-dimensional calculations of the photonic properties. The influence of the tailored photonic environment on the quantum dot spontaneous emission dynamics is studied using spectrally and spatially dependent time-resolved spectroscopy. In ensemble and single dot measurements we show that the photonic crystals strongly enhance the photon extraction efficiency and, therefore, are a promising concept for realizing efficient single-photon sources. Furthermore, we demonstrate single-photon emission from an individual quantum dot that is spectrally detuned from the cavity mode. The need for controlling the spectral dot-cavity detuning is discussed on the basis of shifting either the quantum dot emission via temperature tuning or the cavity mode emission via a thin film deposition technique. Finally, we discuss the recently discovered non-resonant coupling mechanism between quantum dot emission and cavity mode for large detunings which drastically lowers the purity of single-photon emission from dots that are spectrally coupled to nanocavity modes.

  15. Phase-sensitive detection of optical resonances by using an acousto-optic modulator in the Raman - Nath diffraction mode

    International Nuclear Information System (INIS)

    Baryshev, V N; Domnin, Yu S; Kopylov, L N

    2007-01-01

    A new method for frequency control of an external cavity diode laser without direct modulation of the injection current is proposed. The Pound - Drever optical heterodyne technique or the method of frequency control by frequency-modulated sidebands, in which an acousto-optic modulator operating in the Raman - Nath diffraction mode is used as an external phase modulator, can be employed to obtain error signals upon automatic frequency locking of the diode laser to the saturated absorption resonances within the D 2 line of cesium atoms or to the optical cavity resonances. (control of laser radiation parameters)

  16. Continuously tunable monomode mid-infrared vertical external cavity surface emitting laser on Si

    Science.gov (United States)

    Khiar, A.; Rahim, M.; Fill, M.; Felder, F.; Hobrecker, F.; Zogg, H.

    2010-10-01

    A tunable PbTe based mid-infrared vertical external cavity surface emitting laser is described. The active part is a ˜1 μm thick PbTe layer grown epitaxially on a Bragg mirror on the Si-substrate. The cavity is terminated with a curved Si/SiO Bragg top mirror and pumped optically with a 1.55 μm laser. Cavity length is <100 μm in order that only one longitudinal mode is supported. By changing the cavity length, up to 5% wavelength continuous and mode-hop free tuning is achieved at fixed temperature. The total tuning extends from 5.6 to 4.7 μm at 100-170 K operation temperature.

  17. New IR-UV gas sensor to energy and transport sector

    Energy Technology Data Exchange (ETDEWEB)

    Fateev, A.; Clausen, S.

    2010-12-15

    In situ simultaneous measurements of gas temperature and gas composition are of great interest in combustion research and give useful information about conditions, chemical reactions and gas mixing in many industrial processes. An optically based technique is beneficial because it is non-intrusive, accurate, fast and can be performed in situ for various extremely hard conditions. In humid and hot gas flows UV technique is more sensitive than FTIR one for fast gas concentration measurements of NO and SO{sub 2} and gives a great opportunity for simultaneous measurements of O{sub 2} concentration. Analysis of the fine structure of the UV absorption bands of, for example, NO, SO{sub 2} or O{sub 2} allows also to determine a value of the gas temperature. Absorption cross sections of CO{sub 2}, H{sub 2}O and SO{sub 2} measured using Risoe DTU's hot gas cell facility at elevated temperatures up to 1500 deg. C are reported. Design of a new developed 9-m long water-cooled fiber-optic probe with removable optical head suitable for fast IR/UV local gas absorption/emission measurements is described. The probe performance was successfully tested in several trial measurements on full scale multi-fuel fired boiler. A concept of fast time/spectralresolved measurements has been used in measurements on a large ship engine based on IR and UV broad band spectroscopy. (Author)

  18. UV-responsive polyvinyl alcohol nanofibers prepared by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Khatri, Zeeshan, E-mail: zeeshan.khatri@faculty.muet.edu.pk [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Ali, Shamshad [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Khatri, Imran [Department of Entomology, Sindh Agriculture University, Tandojam (Pakistan); Mayakrishnan, Gopiraman [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Kim, Seong Hun [Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Ick-Soo, E-mail: kim@shinshu-u.ac.jp [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan)

    2015-07-01

    Graphical abstract: - Highlights: • UV responsive PVA nanofibers were prepared via electrospinning. • Quick response codes were recorded multiple times on UV responsive nanofibers. • The rate of photo-coloration was found faster than the rate of photo-reversibility. - Abstract: We report UV-responsive polyvinyl alcohol (PVA) nanofibers for potential application for recording and erasing quick response (QR) codes. We incorporate 1′-3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2′-(2H)-indole] (indole) and,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3′-[3H] phenanthr [9,10-b] (1,4) oxazine] (oxazine) into PVA polymer matrix via electrospinning technique. The resultant nanofibers were measured for recording–erasing, photo-coloration and thermal reversibility. The rate of photo-coloration of PVA–indole nanofibers was five times higher than the PVA–oxazine nanofibers, whereas the thermal reversibility found to be more than twice as fast as PVA–oxazine nanofibers. Results showed that the resultant nanofibers have very good capability of recording QR codes multiple times. The FTIR spectroscopy and SEM were employed to characterize the electrospun nanofibers. The UV-responsive PVA nanofibers have great potentials as a light-driven nanomaterials incorporated within sensors, sensitive displays and in optical devices such as erasable and rewritable optical storage.

  19. UV-responsive polyvinyl alcohol nanofibers prepared by electrospinning

    International Nuclear Information System (INIS)

    Khatri, Zeeshan; Ali, Shamshad; Khatri, Imran; Mayakrishnan, Gopiraman; Kim, Seong Hun; Kim, Ick-Soo

    2015-01-01

    Graphical abstract: - Highlights: • UV responsive PVA nanofibers were prepared via electrospinning. • Quick response codes were recorded multiple times on UV responsive nanofibers. • The rate of photo-coloration was found faster than the rate of photo-reversibility. - Abstract: We report UV-responsive polyvinyl alcohol (PVA) nanofibers for potential application for recording and erasing quick response (QR) codes. We incorporate 1′-3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2′-(2H)-indole] (indole) and,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3′-[3H] phenanthr [9,10-b] (1,4) oxazine] (oxazine) into PVA polymer matrix via electrospinning technique. The resultant nanofibers were measured for recording–erasing, photo-coloration and thermal reversibility. The rate of photo-coloration of PVA–indole nanofibers was five times higher than the PVA–oxazine nanofibers, whereas the thermal reversibility found to be more than twice as fast as PVA–oxazine nanofibers. Results showed that the resultant nanofibers have very good capability of recording QR codes multiple times. The FTIR spectroscopy and SEM were employed to characterize the electrospun nanofibers. The UV-responsive PVA nanofibers have great potentials as a light-driven nanomaterials incorporated within sensors, sensitive displays and in optical devices such as erasable and rewritable optical storage

  20. Development of an online UV-visible microspectrophotometer for a macromolecular crystallography beamline.

    Science.gov (United States)

    Shimizu, Nobutaka; Shimizu, Tetsuya; Baba, Seiki; Hasegawa, Kazuya; Yamamoto, Masaki; Kumasaka, Takashi

    2013-11-01

    Measurement of the UV-visible absorption spectrum is a convenient technique for detecting chemical changes of proteins, and it is therefore useful to combine spectroscopy and diffraction studies. An online microspectrophotometer for the UV-visible region was developed and installed on the macromolecular crystallography beamline, BL38B1, at SPring-8. This spectrophotometer is equipped with a difference dispersive double monochromator, a mercury-xenon lamp as the light source, and a photomultiplier as the detector. The optical path is mostly constructed using mirrors, in order to obtain high brightness in the UV region, and the confocal optics are assembled using a cross-slit diaphragm like an iris to eliminate stray light. This system can measure optical densities up to a maximum of 4.0. To study the effect of radiation damage, preliminary measurements of glucose isomerase and thaumatin crystals were conducted in the UV region. Spectral changes dependent on X-ray dose were observed at around 280 nm, suggesting that structural changes involving Trp or Tyr residues occurred in the protein crystal. In the case of the thaumatin crystal, a broad peak around 400 nm was also generated after X-ray irradiation, suggesting the cleavage of a disulfide bond. Dose-dependent spectral changes were also observed in cryo-solutions alone, and these changes differed with the composition of the cryo-solution. These responses in the UV region are informative regarding the state of the sample; consequently, this device might be useful for X-ray crystallography.