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Sample records for infrared wavelength photonic

  1. Silicon photonic crystal thermal emitter at near-infrared wavelengths

    PubMed Central

    O’Regan, Bryan J.; Wang, Yue; Krauss, Thomas F.

    2015-01-01

    Controlling thermal emission with resonant photonic nanostructures has recently attracted much attention. Most of the work has concentrated on the mid-infrared wavelength range and/or was based on metallic nanostructures. Here, we demonstrate the experimental operation of a resonant thermal emitter operating in the near-infrared (≈1.5 μm) wavelength range. The emitter is based on a doped silicon photonic crystal consisting of a two dimensional square array of holes and using silicon-on-insulator technology with a device-layer thickness of 220 nm. The device is resistively heated by passing current through the photonic crystal membrane. At a temperature of ≈1100 K, we observe relatively sharp emission peaks with a Q factor around 18. A support structure system is implemented in order to achieve a large area suspended photonic crystal thermal emitter and electrical injection. The device demonstrates that weak absorption together with photonic resonances can be used as a wavelength-selection mechanism for thermal emitters, both for the enhancement and the suppression of emission. PMID:26293111

  2. Silicon photonic crystal thermal emitter at near-infrared wavelengths.

    PubMed

    O'Regan, Bryan J; Wang, Yue; Krauss, Thomas F

    2015-01-01

    Controlling thermal emission with resonant photonic nanostructures has recently attracted much attention. Most of the work has concentrated on the mid-infrared wavelength range and/or was based on metallic nanostructures. Here, we demonstrate the experimental operation of a resonant thermal emitter operating in the near-infrared (≈1.5 μm) wavelength range. The emitter is based on a doped silicon photonic crystal consisting of a two dimensional square array of holes and using silicon-on-insulator technology with a device-layer thickness of 220 nm. The device is resistively heated by passing current through the photonic crystal membrane. At a temperature of ≈1100 K, we observe relatively sharp emission peaks with a Q factor around 18. A support structure system is implemented in order to achieve a large area suspended photonic crystal thermal emitter and electrical injection. The device demonstrates that weak absorption together with photonic resonances can be used as a wavelength-selection mechanism for thermal emitters, both for the enhancement and the suppression of emission. PMID:26293111

  3. Current status of three-dimensional silicon photonic crystals operating at infrared wavelengths

    SciTech Connect

    LIN,SHAWN-YU; FLEMING,JAMES G.; SIGALAS,M.M.; BISWAS,R.; HO,K.M.

    2000-05-11

    In this paper, the experimental realization and promises of three-dimensional (3D) photonic crystals in the infrared and optical wavelengths will be described. Emphasis will be placed on the development of new 3D photonic crystals, the micro- and nano-fabrication techniques, the construction of high-Q micro-cavities and the creation of 3D waveguides.

  4. Temperature Dependence of Novel Single-Photon Detectors in the Long-Wavelength Infrared Range

    NASA Astrophysics Data System (ADS)

    Ueda, Takeji; An, Zhenghua; Komiyama, Susumu

    2011-05-01

    Novel single-photon detectors, called Charge-sensitive Infrared Phototransistor (CSIP), have been developed in the long wavelength infrared (LWIR) range. The devices are fabricated in GaAs/AlGaAs double-quantum-well (DQW) structure, and do not require ultralow temperatures ( T < 1 K) for operation. Figures of merit are determined in a T-range of 4.2 K˜30 K by using a homemade all-cryogenic spectrometer. We found that the photo-signal persists up to around 30 K. Excellent specific detectivity D * = 9.6 × 1014 cm Hz1/2/W and noise equivalent power NEP = 8.3 × 10-19 W/Hz1/2 are derived up to T = 23 K. The dynamic range of detection exceeds 106, roughly ranging from attowatt to picowatt levels. These values are by a few orders of magnitude higher than that of the state-of-the-art values of other detectors. Simple planar structure of CSIPs is feasible for array fabrication and will make it possible to monolithically integrate with reading circuit. CSIPs are, therefore, not only extremely sensitive but also suitable for practical use in wide ranging applications.

  5. Fabrication of ceramic layer-by-layer infrared wavelength photonic band gap crystals

    NASA Astrophysics Data System (ADS)

    Kang, Henry Hao-Chuan

    Photonic band gap (PBG) crystals, also known as photonic crystals, are periodic dielectric structures which form a photonic band gap that prohibit the propagation of electromagnetic (EM) waves of certain frequencies at any incident angles. Photonic crystals have several potential applications including zero-threshold semiconductor lasers, the inhibiting spontaneous emission, dielectric mirrors, and wavelength filters. If defect states are introduced in the crystals, light can be guided from one location to another or even a sharp bending of light in submicron scale can be achieved. This generates the potential for optical waveguide and optical circuits, which will contribute to the improvement in the fiber-optic communications and the development of high-speed computers. The goal of this dissertation research is to explore techniques for fabricating 3D ceramic layer-by-layer (LBL) photonic crystals operating in the infrared frequency range, and to characterize the infilling materials properties that affect the fabrication process as well as the structural and optical properties of the crystals. While various approaches have been reported in literature for the fabrication of LBL structure, the uniqueness of this work ties with its cost-efficiency and relatively short process span. Besides, very few works have been reported on fabricating ceramic LBL crystals at mid-IR frequency range so far. The fabrication techniques reported here are mainly based on the concepts of microtransfer molding with the use of polydimethyl siloxane (PDMS) as molds/stamps. The infilling materials studied include titanium alkoxide precursors and aqueous suspensions of nanosize titania particles (slurries). Various infilling materials were synthesized to determine viscosities, effects on drying and firing shrinkages, effects on film surface roughness, and their moldability. Crystallization and phase transformation of the materials were also monitored using DTA, TGA and XRD. Mutilayer crystal

  6. Visible and near infrared wavelength photonic crystal fiber splitter for multiwavelength spectral domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Eom, Joo Beom; Min, Eun Jung; Lee, Byeong Ha

    2012-01-01

    We report the fabrication and performance of the 2×2 photonic crystal fiber (PCF) splitter that was designed as a single mode splitter at the visible and near infrared and used as the beam splitter for a spectral domain optical coherence tomography (SD-OCT) system. The PCF splitter has been made by coupling PCFs to a planar lightwave circuit (PLC) splitter chip. The PLC splitter chip was fabricated to have a single mode property with 630 nm cutoff wavelength and the PCFs were securely connected to the PLC chip through PCF block arrays having lithographically fabricated V grooves. The core width of the splitter chip was about 4 μm×4 μm and the core-cladding index difference was about 0.15%. With the implemented PCF PLC splitter, we have obtained a low excess loss of 1.2 dB and a low polarization-dependent loss of 0.19 dB at 680 nm with wide band coupling property. With the proposed 2×2 PCF splitter, SD-OCT images of human finger, nail, and tooth successfully obtained by using 680 nm, 840 nm, and 930 nm SLD source. This PCF PLC splitter is expected to have high resolution OCT.

  7. Fabrication of Ceramic Layer-by-Layer Infrared Wavelength Photonic Band Gap Crystals

    SciTech Connect

    Henry Hao-Chuan Kang

    2004-12-19

    Photonic band gap (PBG) crystals, also known as photonic crystals, are periodic dielectric structures which form a photonic band gap that prohibit the propagation of electromagnetic (EM) waves of certain frequencies at any incident angles. Photonic crystals have several potential applications including zero-threshold semiconductor lasers, the inhibition of spontaneous emission, dielectric mirrors, and wavelength filters. If defect states are introduced in the crystals, light can be guided from one location to another or even a sharp bending of light in micron scale can be achieved. This generates the potential for optical waveguide and optical circuits, which will contribute to the improvement in the fiber-optic communications and the development of high-speed computers.

  8. Ultrafast superconducting single-photon detectors for near-infrared-wavelength quantum communications

    NASA Astrophysics Data System (ADS)

    Verevkin, A.; Pearlman, A.; Słysz, W.; Zhang, J.; Currie, M.; Korneev, A.; Chulkova, G.; Okunev, O.; Kouminov, P.; Smirnov, K.; Voronov, B.; Gol'Tsman, G. N.; Sobolewski, Roman

    2004-09-01

    The paper reports progress on the design and development of niobium-nitride, superconducting single-photon detectors (SSPDs) for ultrafast counting of near-infrared photons for secure quantum communications. The SSPDs operate in the quantum detection mode, based on photon-induced hotspot formation and subsequent appearance of a transient resistive barrier across an ultrathin and submicron-width superconducting stripe. The devices are fabricated from 3.5 nm thick NbN films and kept at cryogenic (liquid helium) temperatures inside a cryostat. The detector experimental quantum efficiency in the photon-counting mode reaches above 20% in the visible radiation range and up to 10% at the 1.3-1.55 µm infrared range. The dark counts are below 0.01 per second. The measured real-time counting rate is above 2 GHz and is limited by readout electronics (the intrinsic response time is below 30 ps). The SSPD jitter is below 18 ps, and the best-measured value of the noise-equivalent power (NEP) is 2 × 10-18 W/Hz1/2 at 1.3 µm. In terms of photon-counting efficiency and speed, these NbN SSPDs significantly outperform semiconductor avalanche photodiodes and photomultipliers.

  9. Ultrafast superconducting single-photon detectors for infrared wavelength quantum communications

    NASA Astrophysics Data System (ADS)

    Verevkin, Aleksandr A.; Pearlman, Aaron; Slysz, Wojtek; Zhang, Jin; Sobolewski, Roman; Chulkova, Galina; Okunev, Oleg; Kouminov, Pavel; Drakinskij, Vladimir; Smirnov, Konstantin; Kaurova, Natalia; Voronov, Boris; Gol'tsman, Gregory; Currie, Marc

    2003-08-01

    We have developed a new class of superconducting single-photon detectors (SSPDs) for ultrafast counting of infrared (IR) photons for secure quantum communications. The devices are operated on the quantum detection mechanism, based on the photon-induced hotspot formation and subsequent appearance of a transient resistive barrier across an ultrathin and submicron-wide superconducting stripe. The detectors are fabricated from 3.5-nm-thick NbN films and they operate at 4.2 K inside a closed-cycle refrigerator or liquid helium cryostat. Various continuous and pulsed laser sources have been used in our experiments, enabling us to determine the detector experimental quantum efficiency (QE) in the photon-counting mode, response time, time jitter, and dark counts. Our 3.5-nm-thick SSPDs reached QE above 15% for visible light photons and 5% at 1.3 - 1.5 μm infrared range. The measured real-time counting rate was above 2 GHz and was limited by the read-out electronics (intrinsic response time is <30 ps). The measured jitter was <18 ps, and the dark counting rate was <0.01 per second. The measured noise equivalent power (NEP) is 2 x 10-18 W/Hz1/2 at λ = 1.3 μm. In near-infrared range, in terms of the counting rate, jitter, dark counts, and overall sensitivity, the NbN SSPDs significantly outperform their semiconductor counterparts. An ultrafast quantum cryptography communication technology based on SSPDs is proposed and discussed.

  10. Hyperuniform disordered photonic bandgap materials, from microwave to infrared wavelength regime

    NASA Astrophysics Data System (ADS)

    Man, Weining

    Recently, we have introduced a new class of hyperuniform disordered (HUD) photonic bandgap (PBG) materials enabled by a novel constrained optimization method for engineering the material's Fourier transform to be continuous, isotropic and stealthy. Their structure factor S (k) is equal to zero for small kand exhibits a broad ring of maximum values around a characteristic wave-length range. Experimentally, an isotropic complete PBG (at all angles and for all polarizations) in an alumina-based HUD structure and single-polarized PBGs for plastic-based HUD structure have been demonstrated. Using measured and simulated transmission and phase delay information through these HUD structures, we also unfolded their band structures and reconstructed the effective dispersion relations of propagating electromagnetic modes in them. The intrinsic isotropy in these disordered structures is an inherent advantage associated with the lack of crystalline order, offering unprecedented freedom for functional defect design impossible to achieve in photonic crystals. In the microwave regime, we have shown the creation of freeform waveguides, which can channel photons robustly along arbitrarily curved paths and around sharp bends, and be decorated with defects to produce sharply resonant structures useful for filtering and frequency splitting. Recent simulation and experimental results for waveguides and modulators based on submicron-scale planar hyperuniform disordered PBG structures further highlight their ability to serve as highly compact, flexible and energy-efficient platforms for photonic integrated circuits. NSF DMR-1308084, EPSRC (UK) DTG Grant KD5050, EPSRC (UK) Strategic Equipment Grant EP/M008576/1, NSF SBIR-1345168, NSF MRI-1040444.

  11. Long wavelength infrared detector

    NASA Technical Reports Server (NTRS)

    Vasquez, Richard P. (Inventor)

    1993-01-01

    Long wavelength infrared detection is achieved by a detector made with layers of quantum well material bounded on each side by barrier material to form paired quantum wells, each quantum well having a single energy level. The width and depth of the paired quantum wells, and the spacing therebetween, are selected to split the single energy level with an upper energy level near the top of the energy wells. The spacing is selected for splitting the single energy level into two energy levels with a difference between levels sufficiently small for detection of infrared radiation of a desired wavelength.

  12. Multiple-return single-photon counting of light in flight and sensing of non-line-of-sight objects at shortwave infrared wavelengths.

    PubMed

    Laurenzis, Martin; Klein, Jonathan; Bacher, Emmanuel; Metzger, Nicolas

    2015-10-15

    Time-of-flight sensing with single-photon sensitivity enables new approaches for the localization of objects outside a sensor's field of view by analyzing backscattered photons. In this Letter, the authors have studied the application of Geiger-mode avalanche photodiode arrays and eye-safe infrared lasers, and provide experimental data of the direct visualization of backscattering light in flight, and direct vision and indirect vision of targets in line-of-sight and non-line-of-sight configurations at shortwave infrared wavelengths. PMID:26469627

  13. Ultra-low infrared emissivity at the wavelength of 3-5 μm from Ge/ZnS one-dimensional photonic crystal

    NASA Astrophysics Data System (ADS)

    Zhang, Weigang; Xu, Guoyue; Shi, Xiao; Ma, Hui; Li, Lei

    2015-04-01

    Ge/ZnS one-dimensional photonic crystal (1DPC) was successfully prepared by alternating thin films of Ge and ZnS on the quartz substrate by using the optical coating technology. The microstructure and spectral emissivity of as-prepared 1DPC were characterized by using scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FTIR), respectively. The test result of spectral emissivity shows that the as-prepared 1DPC has ultra-low infrared emissivity at the wavelength of 3-5 μm, the average emissivity can be as low as 0.052, fully reached the level of high conductive precious metal films. The results indicate that not only the high conductive precious metal films have ultra-low infrared emissivity, the semiconductor materials such as Ge and ZnS through rational design of 1DPC can also get ultra-low infrared emissivity. The as-prepared 1DPC with ultra-low infrared emissivity is promising for use as materials for efficient solar thermal collectors and infrared stealth.

  14. Metallic photonic crystals at optical wavelengths

    NASA Astrophysics Data System (ADS)

    El-Kady, I.; Sigalas, M. M.; Biswas, R.; Ho, K. M.; Soukoulis, C. M.

    2000-12-01

    We theoretically study three-dimensional metallic photonic-band-gap (PBG) materials at near-infrared and optical wavelengths. Our main objective is to find the importance of absorption in the metal and the suitability of observing photonic band gaps in this structure. For that reason, we study simple cubic structures and the metallic scatterers are either cubes or interconnected metallic rods. Several different metals have been studied (aluminum, gold, copper, and silver). Copper gives the smallest absorption and aluminum is more absorptive. The isolated metallic cubes are less lossy than the connected rod structures. The calculations suggest that isolated copper scatterers are very attractive candidates for the fabrication of photonic crystals at the optical wavelengths.

  15. trans/cis-Isomerization of fluorene-bridged azo chromophore with significant two-photon absorbability at near-infrared wavelength.

    PubMed

    Chu, Chih-Chien; Chang, Ya-Chi; Tsai, Bo-Kai; Lin, Tzu-Chau; Lin, Ja-Hon; Hsiao, Vincent K S

    2014-12-01

    Azo-containing materials have been proven to possess second-order nonlinear optical (NLO) properties, but their third-order NLO properties, which involves two-photon absorption (2PA), has rarely been reported. In this study, we demonstrate a significant 2PA behavior of the novel azo chromophore incorporated with bilateral diphenylaminofluorenes (DPAFs) as a π framework. The electron-donating DPAF moieties cause a redshifted π-π* absorption band centered at 470 nm, thus allowing efficient blue-light-induced trans-to-cis photoisomerization with a rate constant of 2.04 × 10(-1) min(-1) at the photostationary state (PSS). The open-aperture Z-scan technique that adopted a femtosecond (fs) pulse laser as excitation source shows an appreciably higher 2PA cross-section for the fluorene-derived azo chromophore than that for common azobenzene dyes at near-infrared wavelength (λex =800 nm). Furthermore, the fs 2PA response is quite uniform regardless of the molecular geometry. On the basis of the computational modeling, the intramolecular charge-transfer (ICT) process from peripheral diphenylamines to the central azo group through a fluorene π bridge is crucial to this remarkable 2PA behavior. PMID:25294108

  16. Compact fixed wavelength femtosecond oscillators for multi-photon imaging

    NASA Astrophysics Data System (ADS)

    Hakulinen, T.; Klein, J.; Zadoyan, R.; Baldacchini, T.; Franke, T.

    2015-03-01

    In recent years two-photon microscopy with fixed-wavelength has raised increasing interest in life-sciences: Two-photon (2P) absorption spectra of common dyes are broader than single-photon ones. Therefore, excitation of several dyes simultaneously with a single IR laser wavelength is feasible and could be seen as an advantage in 2P microscopy. We used pulsed fixed-wavelength infrared lasers with center wavelength at 1040 nm, for two-photon microscopy in a variety of biologically relevant samples, among these a mouse brain sample, a mouse artery (within the animal, acute preparation), and a preparation of mouse bladder. The 1040 nm laser proved to be efficient not only in exciting fluorescence from yellow fluorescent protein (YFP) and red fluorescent dyes, but also for second harmonic generation (SHG) signals from muscle tissue and collagen. With this work we demonstrate that economical, small-footprint fixedwavelength lasers can present an interesting alternative to tunable lasers that are commonly used in multiphoton microscopy.

  17. SDIO long wavelength infrared detector requirements

    NASA Technical Reports Server (NTRS)

    Duston, Dwight

    1990-01-01

    The Strategic Defense Initiative Organization (SDIO) has a significant requirement for infrared sensors for surveillance, tracking and discrimination of objects in space. Projected SDIO needs cover the range from short wavelengths out to 30 microns. Large arrays are required, and producibility and cost are major factors. The SDIO is pursuing several approaches including innovative concepts based on semiconductors and superconductors.

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

    SciTech Connect

    Kita, Tomohiro Tang, Rui; Yamada, Hirohito

    2015-03-16

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

  19. Short wavelength infrared hybrid focal plane arrays

    NASA Technical Reports Server (NTRS)

    Vural, K.; Blackwell, J. D.; Marin, E. C.; Edwall, D. D.; Rode, J. P.

    1983-01-01

    The employment of area focal plane arrays (FPA) has made it possible to obtain second generation infrared imaging systems with high resolution and sensitivity. The Short Wavelength Infrared (SWIR) region (1-2.5 microns) is of importance for imaging objects at high temperature and under conditions of reflected sunlight. The present investigation is concerned with electrooptical characterization results for 32 x 32 SWIR detector arrays and FPAs which are suitable for use in a prototype imaging spectrometer. The employed detector material is Hg(1-x)Cd(x)Te grown by liquid phase epitaxy on a CdTe transparent substrate. Attention is given to details of processing, the design of the detector array, the multiplexer, the fabrication of the hybrid FPA, and aspects of performance.

  20. Group IV mid-infrared photonics

    NASA Astrophysics Data System (ADS)

    Mashanovich, G. Z.; Nedeljkovic, M.; Soler Penades, J.; Mitchell, C. J.; Khokhar, A. Z.; Littlejohns, C. J.; Stankovic, S.; Troia, B.; Wang, Y.; Reynolds, S.; Passaro, V. M. N.; Shen, L.; Healy, N.; Peacock, A. C.; Alonso-Ramos, C.; Ortega-Monux, A.; Wanguemert-Perez, G.; Molina-Fernandez, I.; Rowe, D. J.; Wilkinson, J. S.; Cheben, P.; Ackert, J. J.; Knights, A. P.; Thomson, D. J.; Gardes, F. Y.

    2015-02-01

    In this paper we present SOI, suspended Si, and Ge-on-Si photonic platforms and devices for the mid-infrared. We demonstrate low loss strip and slot waveguides in SOI and show efficient strip-slot couplers. A Vernier configuration based on racetrack resonators in SOI has been also investigated. Mid-infrared detection using defect engineered silicon waveguides is reported at the wavelength of 2-2.5 μm. In order to extend transparency of Si waveguides, the bottom oxide cladding needs to be removed. We report a novel suspended Si design based on subwavelength structures that is more robust than previously reported suspended designs. We have fabricated record low loss Ge-on-Si waveguides, as well as several other passive devices in this platform. All optical modulation in Ge is also analyzed.

  1. Short-Wavelength Infrared Views of Messier 81

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The magnificent spiral arms of the nearby galaxy Messier 81 are highlighted in this NASA Spitzer Space Telescope image. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years from Earth.

    Because of its proximity, M81 provides astronomers with an enticing opportunity to study the anatomy of a spiral galaxy in detail. The unprecedented spatial resolution and sensitivity of Spitzer at infrared wavelengths show a clear separation between the several key constituents of the galaxy: the old stars, the interstellar dust heated by star formation activity, and the embedded sites of massive star formation. The infrared images also permit quantitative measurements of the galaxy's overall dust content, as well as the rate at which new stars are being formed.

    The infrared image was obtained by Spitzer's infrared array camera. It is a four-color composite of invisible light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (yellow) and 8.0 microns (red). Winding outward from the bluish-white central bulge of the galaxy, where old stars predominate and there is little dust, the grand spiral arms are dominated by infrared emission from dust. Dust in the galaxy is bathed by ultraviolet and visible light from the surrounding stars. Upon absorbing an ultraviolet or visible-light photon, a dust grain is heated and re-emits the energy at longer infrared wavelengths. The dust particles, composed of silicates (which are chemically similar to beach sand) and polycyclic aromatic hydrocarbons, trace the gas distribution in the galaxy. The well-mixed gas (which is best detected at radio wavelengths) and dust provide a reservoir of raw materials for future star formation.

    The infrared-bright clumpy knots within the spiral arms denote where massive stars are being born in giant H

  2. Multiple wavelength infrared cameras and their biomedical applications

    NASA Astrophysics Data System (ADS)

    Anbar, Michael

    1995-03-01

    There have been substantial advances in multiple wavelength infrared imaging systems that can measure emissivity and temperature of surfaces. Multiplewavelength measurements can be done (1) using an array of detectors, each sensitive to a different range of photon energies; (2) using a tunable filter in front of a broad-band infrared detector; or (3) by using a focal plane array of tunable detectors. In choosing a multiplewavelength infrared camera for biomedical research or for clinical practice, the parameters of importance include cost, spectral resolution, spatial resolution, and response time. For many biological systems the assessment of infrared emissivity and/or fluorescence must be done simultaneously with the temperature measurement, because these parameters may rapidly change independently from each other. In addition to providing accurate absolute temperature readings in any thermological study, the measurement of emissivity and fluorescence and the display of their spatial distribution can be especially helpful in dermatology, dermatological oncology, dermatological pharmacology (assessment of pharmacokinetics and of diaphoretic excretion of drug metabolites), skin toxicology, burns management, assessment of radiation overexposure and microtelecalorimetry of cells, micro-organisms and tissue cultures. The measurement of light induced cutaneous vasoconstriction pose novel biomedical research problems that require the use of multiplewavelength cameras. In addition to the use of more sophisticated cameras, precision clinical telethermometry requires a better controlled environment. One must take into account infrared fluorescence, photoreflectance and light induced vasoconstriction all of which are induced by environmental illumination.

  3. Innovative Long Wavelength Infrared Detector Workshop Proceedings

    NASA Technical Reports Server (NTRS)

    Grunthaner, Frank J.

    1990-01-01

    The focus of the workshop was on innovative long wavelength (lambda less than 17 microns) infrared (LWIR) detectors with the potential of meeting future NASA and DoD long-duration space application needs. Requirements are for focal plane arrays which operate near 65K using active refrigeration with mission lifetimes of five to ten years. The workshop addressed innovative concepts, new material systems, novel device physics, and current progress in relation to benchmark technology. It also provided a forum for discussion of performance characterization, producibility, reliability, and fundamental limitations of device physics. It covered the status of the incumbent HgCdTe technology, which shows encouraging progress towards LWIR arrays, and provided a snapshot of research and development in several new contender technologies.

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

    PubMed

    Jirauschek, Christian; Huber, Robert

    2015-07-01

    We analyze the physics behind the newest generation of rapidly wavelength tunable sources for optical coherence tomography (OCT), retaining a single longitudinal cavity mode during operation without repeated build up of lasing. In this context, we theoretically investigate the currently existing concepts of rapidly wavelength-swept lasers based on tuning of the cavity length or refractive index, leading to an altered optical path length inside the resonator. Specifically, we consider vertical-cavity surface-emitting lasers (VCSELs) with microelectromechanical system (MEMS) mirrors as well as Fourier domain mode-locked (FDML) and Vernier-tuned distributed Bragg reflector (VT-DBR) lasers. Based on heuristic arguments and exact analytical solutions of Maxwell's equations for a fundamental laser resonator model, we show that adiabatic wavelength tuning is achieved, i.e., hopping between cavity modes associated with a repeated build up of lasing is avoided, and the photon number is conserved. As a consequence, no fundamental limit exists for the wavelength tuning speed, in principle enabling wide-range wavelength sweeps at arbitrary tuning speeds with narrow instantaneous linewidth. PMID:26203373

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

    PubMed Central

    Jirauschek, Christian; Huber, Robert

    2015-01-01

    We analyze the physics behind the newest generation of rapidly wavelength tunable sources for optical coherence tomography (OCT), retaining a single longitudinal cavity mode during operation without repeated build up of lasing. In this context, we theoretically investigate the currently existing concepts of rapidly wavelength-swept lasers based on tuning of the cavity length or refractive index, leading to an altered optical path length inside the resonator. Specifically, we consider vertical-cavity surface-emitting lasers (VCSELs) with microelectromechanical system (MEMS) mirrors as well as Fourier domain mode-locked (FDML) and Vernier-tuned distributed Bragg reflector (VT-DBR) lasers. Based on heuristic arguments and exact analytical solutions of Maxwell’s equations for a fundamental laser resonator model, we show that adiabatic wavelength tuning is achieved, i.e., hopping between cavity modes associated with a repeated build up of lasing is avoided, and the photon number is conserved. As a consequence, no fundamental limit exists for the wavelength tuning speed, in principle enabling wide-range wavelength sweeps at arbitrary tuning speeds with narrow instantaneous linewidth. PMID:26203373

  6. Development of Charge Sensitive Infrared Phototransistors for the Far-Infrared Wavelength

    NASA Astrophysics Data System (ADS)

    Nihei, R.; Komiyama, S.; Kawada, M.; Matsuura, S.; Doi, Y.; Satoh, T.; Nakagawa, T.

    2014-08-01

    Ultra-highly-sensitive far-infrared detectors are developed for potential application to astronomy. The detectors exploit a novel mechanism called Charge Sensitive Infrared Phototransistors (CSIPs), in which an upper quantum well (QW) in GaAs/AlGaAs double QW structures is positively charged up by photo-excitation via inter-subband transition. This causes the conductance of the lower QW channel to increase. The device is effectively a phototransistor, in which the upper QW serves as a photo-sensitive gate to the source-drain channel provided by the lower QW. Resultant extraordinary high photoconductive gain makes CSIPs so sensitive as to detect single photons. CSIPs are well established in the mid-infrared ( = 12-20 m), achieving noise equivalent power around 1.9 10 W/Hz with a quantum efficiency of 7 %. CSIPs have been demonstrated to work in longer wavelengths up to 45 m, but the sensitivity was not as high as in the shorter wavelengths, probably due to lower quantum efficiency. Reported here is a remarkable improvement in the performance of longer wavelength CSIPs (45 m), achieved primarily by optimizing the doping concentration in the upper QW. This work indicates that longer wavelength CSIPs are promising detectors for the astronomical application.

  7. Fabrication and characterization of three-dimensional infrared photonic crystals

    NASA Astrophysics Data System (ADS)

    Zavieh, Lisa

    It has been predicted theoretically that photonic crystals can be used to control the propagation of light through dielectric media for wavelengths extending beyond the microwave to include the infrared and the visible. Fabrication of 3-D photonic crystals with a bandgap in the near infrared or visible would have application in the design of a new class of photonic devices that include optical mirrors, waveguides, and cavity resonators. Demonstrations of 3-D photonic crystals have been limited primarily to the microwave and infrared wavelength regimes because of the constraints imposed by the nanometer scale dimensions required for operation in the visible. This thesis presents a novel method of fabricating a simple cubic photonic crystal which potentially can be tailored to operate at any wavelength. Fabrication was broken down into several processing steps, each of which was investigated independently. Design of Experiment (DOE) was used in a parametric study to optimize dry etching conditions by which GaAs/AlxGa1--x As multilayer structures were etched with anisotropic profile and rapid etch rate. Also, the etching properties of diffusion controlled wet lateral etching of buried AlxGa1--xAs layers in hydrofluoric acid solutions (HF) were investigated. Using the results obtained from the etching studies, both dry and wet etching techniques were employed to fabricate the simple-cubic photonic structure. Following fabrication, the photonic crystal was characterized at normal angles and oblique incidence using Fourier transform infrared spectroscopy (FTIR). The experimental results show strong correlation to theoretically predicted values. The simplicity of the process and positive results indicate that it may be possible to scale down the structure to obtain an photonic band lattice with a bandgap of 1.55 mum.

  8. Waveguide-integrated single- and multi-photon detection at telecom wavelengths using superconducting nanowires

    SciTech Connect

    Ferrari, Simone; Kahl, Oliver; Kovalyuk, Vadim; Goltsman, Gregory N.; Korneev, Alexander; Pernice, Wolfram H. P.

    2015-04-13

    We investigate single- and multi-photon detection regimes of superconducting nanowire detectors embedded in silicon nitride nanophotonic circuits. At near-infrared wavelengths, simultaneous detection of up to three photons is observed for 120 nm wide nanowires biased far from the critical current, while narrow nanowires below 100 nm provide efficient single photon detection. A theoretical model is proposed to determine the different detection regimes and to calculate the corresponding internal quantum efficiency. The predicted saturation of the internal quantum efficiency in the single photon regime agrees well with plateau behavior observed at high bias currents.

  9. FY 2006 Infrared Photonics Final Report

    SciTech Connect

    Anheier, Norman C.; Allen, Paul J.; Bernacki, Bruce E.; Ho, Nicolas; Krishnaswami, Kannan; Qiao, Hong; Schultz, John F.

    2006-12-28

    Research done by the Infrared Photonics team at Pacific Northwest National Laboratory (PNNL) is focused on developing miniaturized integrated optics and optical fiber processing methods for mid-wave infrared (MWIR) and long-wave infrared (LWIR) sensing applications by exploiting the unique optical and material properties of chalcogenide glass. PNNL has developed thin-film deposition capabilities, direct laser writing techniques, infrared photonic device demonstration, holographic optical element design and fabrication, photonic device modeling, and advanced optical metrology—all specific to chalcogenide glass. Chalcogenide infrared photonics provides a pathway to quantum cascade laser (QCL) transmitter miniaturization. The high output power, small size, and superb stability and modulation characteristics of QCLs make them amenable for integration as transmitters into ultra-sensitive, ultra-selective point sampling and remote short-range chemical sensors that are particularly useful for nuclear nonproliferation missions.

  10. Quantum-dot spin-photon entanglement via frequency downconversion to telecom wavelength.

    PubMed

    De Greve, Kristiaan; Yu, Leo; McMahon, Peter L; Pelc, Jason S; Natarajan, Chandra M; Kim, Na Young; Abe, Eisuke; Maier, Sebastian; Schneider, Christian; Kamp, Martin; Höfling, Sven; Hadfield, Robert H; Forchel, Alfred; Fejer, M M; Yamamoto, Yoshihisa

    2012-11-15

    Long-distance quantum teleportation and quantum repeater technologies require entanglement between a single matter quantum bit (qubit) and a telecommunications (telecom)-wavelength photonic qubit. Electron spins in III-V semiconductor quantum dots are among the matter qubits that allow for the fastest spin manipulation and photon emission, but entanglement between a single quantum-dot spin qubit and a flying (propagating) photonic qubit has yet to be demonstrated. Moreover, many quantum dots emit single photons at visible to near-infrared wavelengths, where silica fibre losses are so high that long-distance quantum communication protocols become difficult to implement. Here we demonstrate entanglement between an InAs quantum-dot electron spin qubit and a photonic qubit, by frequency downconversion of a spontaneously emitted photon from a singly charged quantum dot to a wavelength of 1,560 nanometres. The use of sub-10-picosecond pulses at a wavelength of 2.2 micrometres in the frequency downconversion process provides the necessary quantum erasure to eliminate which-path information in the photon energy. Together with previously demonstrated indistinguishable single-photon emission at high repetition rates, the present technique advances the III-V semiconductor quantum-dot spin system as a promising platform for long-distance quantum communication. PMID:23151585

  11. Coherent dynamics of a telecom-wavelength entangled photon source

    NASA Astrophysics Data System (ADS)

    Ward, M. B.; Dean, M. C.; Stevenson, R. M.; Bennett, A. J.; Ellis, D. J. P.; Cooper, K.; Farrer, I.; Nicoll, C. A.; Ritchie, D. A.; Shields, A. J.

    2014-02-01

    Quantum networks can interconnect remote quantum information processors, allowing interaction between different architectures and increasing net computational power. Fibre-optic telecommunications technology offers a practical platform for routing weakly interacting photonic qubits, allowing quantum correlations and entanglement to be established between distant nodes. Although entangled photons have been produced at telecommunications wavelengths using spontaneous parametric downconversion in nonlinear media, as system complexity increases their inherent excess photon generation will become limiting. Here we demonstrate entangled photon pair generation from a semiconductor quantum dot at a telecommunications wavelength. Emitted photons are intrinsically anti-bunched and violate Bell’s inequality by 17 standard deviations High-visibility oscillations of the biphoton polarization reveal the time evolution of the emitted state with exceptional clarity, exposing long coherence times. Furthermore, we introduce a method to evaluate the fidelity to a time-evolving Bell state, revealing entanglement between photons emitted up to 5 ns apart, exceeding the exciton lifetime.

  12. 128 x 128 Pixel long wavelength infrared acquisition camera

    SciTech Connect

    LeVan, P.D.; Colucci, D.; Cowan, W.D.; Figie, B.D.; Stewart, E.J.

    1994-12-31

    This paper describes a Phillips Laboratory internal design for a high sensitivity, large field of view infrared acquisition camera. Currently, the acquisition of a satellite with the 1.5 meter telescope of the Starfire Optical Range typically requires a sunlit target and dark sky. However, the level of thermal radiation from such a satellite is often sufficiently high in the Long Wavelength Infrared (LWIR) to permit detection with ground based telescopes irrespective of target illumination. The drawbacks of LWIR acquisition include the high levels of thermal radiation from both the telescope and the atmosphere which pose two constraints: (1), the ``background signal`` usually exceeds the target signal and must be removed on time scales over which it is relatively constant, and (2), associated with the background signal is a noise level that dominates all system noise sources. The background signal level at the detector array for the application varies between 10{sup 15} to 10{sup 16} photons sec{sup {minus}1} cm{sup {minus}2}, depending on the infrared bandpass used. The optical design for the LWIR acquisition camera maps a 128 x 128 pixel detector array onto a two milliradian (mrad) scene. The optical design uses two aspheric lenses, one to re-image the field onto a cold field stop, and the telescope pupil onto a cryogenic chopping mirror and collocated radiation stop. The second lens re-images the field stop onto the detector array. Aberrations are designed to be better than diffraction limited over the entire two mrad field of view. The end product of the acquisition system is a video display of the infrared scene, with the background signal removed. A user then positions mouse-driven cross hairs over a target in the scene. The resulting position and time update is used to revise the target ephemeris, and to provide pointing information for target acquisition by other SOR tracking platforms.

  13. FY 2005 Infrared Photonics Final Report

    SciTech Connect

    Anheier, Norman C.; Allen, Paul J.; Ho, Nicolas; Krishnaswami, Kannan; Johnson, Bradley R.; Sundaram, S. K.; Riley, Bradley M.; Martinez, James E.; Qiao, Hong; Schultz, John F.

    2005-12-01

    Research done by the Infrared Photonics team at Pacific Northwest National Laboratory (PNNL) is focused on developing miniaturized integrated optics for mid-wave infrared (MWIR) and long-wave infrared (LWIR) sensing applications by exploiting the unique optical and material properties of chalcogenide glass. PNNL has developed thin-film deposition capabilities, direct laser writing techniques, infrared photonic device demonstration, holographic optical element design and fabrication, photonic device modeling, and advanced optical metrology—all specific to chalcogenide glass. Chalcogenide infrared photonics provides a pathway to quantum cascade laser (QCL) transmitter miniaturization. QCLs provide a viable infrared laser source for a new class of laser transmitters capable of meeting the performance requirements for a variety of national security sensing applications. The high output power, small size, and superb stability and modulation characteristics of QCLs make them amenable for integration as transmitters into ultra-sensitive, ultra-selective point sampling and remote short-range chemical sensors that are particularly useful for nuclear nonproliferation missions. During FY 2005, PNNL’s Infrared Photonics research team made measurable progress exploiting the extraordinary optical and material properties of chalcogenide glass to develop miniaturized integrated optics for mid-wave infrared (MWIR) and long-wave infrared (LWIR) sensing applications. We investigated sulfur purification methods that will eventually lead to routine production of optical quality chalcogenide glass. We also discovered a glass degradation phenomenon and our investigation uncovered the underlying surface chemistry mechanism and developed mitigation actions. Key research was performed to understand and control the photomodification properties. This research was then used to demonstrate several essential infrared photonic devices, including LWIR single-mode waveguide devices and

  14. FY 2004 Infrared Photonics Final Report

    SciTech Connect

    Anheier, Norman C.; Allen, Paul J.; Keller, Paul E.; Bennett, Wendy D.; Martin, Peter M.; Johnson, Bradley R.; Sundaram, S. K.; Riley, Brian J.; Martinez, James E.; Qiao, Hong; Schultz, John F.

    2004-10-01

    Research done by the Infrared Photonics team at PNNL is focused on developing miniaturized integrated optics for the MWIR and LWIR by exploiting the unique optical and material properties of chalcogenide glass. PNNL has developed thin film deposition capabilities, direct-laser writing techniques, IR photonic device demonstration, holographic optical element design and fabrication, photonic device modeling, and advanced optical metrology - all specific to chalcogenide glass. Chalcogenide infrared photonics provides a pathway to Quantum Cascade Laser (QCL) transmitter miniaturization. QCLs provide a viable infrared laser source for a new class of laser transmitters capable of meeting the performance requirements for a variety of national security sensing applications. The high output power, small size, and superb stability and modulation characteristics of QCLs make them amenable for integration as transmitters into ultra-sensitive, ultra-selective point sampling and remote short-range chemical sensors that are particularly useful for nuclear nonproliferation missions.

  15. Photoluminescence Study of Long Wavelength Superlattice Infrared Detectors

    NASA Technical Reports Server (NTRS)

    Hoglund, Linda; Khoshakhlagh, Arezou; Soibel, Alexander; Ting, David Z.; Hill, Cory J.; Keo, Sam; Gunapala, Sarath D.

    2011-01-01

    In this paper, the relation between the photoluminescence (PL) intensity and the PL peak wavelength was studied. A linear decrease of the PL intensity with increasing cut-off wavelength of long wavelength infrared CBIRDs was observed at 77 K and the trend remained unchanged in the temperature range 10 - 77 K. This relation between the PL intensity and the peak wavelength can be favorably used for comparison of the optical quality of samples with different PL peak wavelengths. A strong increase of the width of the PL spectrum in the studied temperature interval was observed, which was attributed to thermal broadening.

  16. Minority carrier lifetime in mid-wavelength infrared InAs/InAsSb superlattices: Photon recycling and the role of radiative and Shockley-Read-Hall recombination mechanisms

    SciTech Connect

    Höglund, L.; Ting, D. Z.; Soibel, A.; Fisher, A.; Khoshakhlagh, A.; Hill, C. J.; Keo, S.; Gunapala, S. D.

    2014-11-10

    The influence of radiative recombination on the minority carrier lifetime in mid-wavelength InAs/InAsSb superlattices was investigated. From the lifetime's dependence on temperature, photon recycling, and carrier concentration, it was demonstrated that radiative lifetime dominates for carrier concentrations >5 × 10{sup 14} cm{sup −3}, and Shockley-Read-Hall recombination starts to dominate the minority carrier lifetime for carrier concentrations <5 × 10{sup 14} cm{sup −3}. An observed increase of the minority carrier lifetime with increasing superlattice thickness was attributed to photon recycling, and good agreement between measured and theoretical values of the photon recycling factor was obtained.

  17. The Universe at Infrared and Submillimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Dwek, E.; Arendt, R. G.; Benford, D. J.; Mather, J. C.; Moseley, S. H.; Shafer, R. A.; Staguhn, J.

    2004-01-01

    Far infrared and submillimeter surveys offer unique information on the early stages of galaxy formation and evolution, and the cosmic history of star formation and metal enrichment. This paper presents various model results that can be used in the interpretation of far-IR and submm surveys with different diameter telescopes.

  18. Mid-infrared supercontinuum generation in silica photonic crystal fibers.

    PubMed

    Bi, Wanjun; Gao, Juanjuan; Li, Xia; Xiong, Liangming; Liao, Meisong

    2016-08-10

    A mid-infrared supercontinuum (SC) light source, which has important applications in many fields, has been extensively investigated in soft glass fibers. However, the poor instinct properties of soft glass fibers and the development of ultrashort pulse lasers left an opportunity for mid-infrared SC generation in silica fiber. Until now, silica fiber has been the commonly used medium for SC generation due to its outstanding properties. In this paper, mid-infrared SC generation in short silica photonic crystal fibers (PCFs) is investigated theoretically and systematically. In the case of a 1550�nm pump, the soliton self-frequency shift effect is utilized to extend the long wavelength edge of SC. Adopting a fiber that has a zero dispersion wavelength away from the pump pulse is a benefit for the suppression of blue spectral component and energy distribution in the long wavelength band. In the case of a 1950�nm pump, the generation of a red-shifted dispersive wave is an efficient way to extend the long wavelength edge of SC. Additionally, the coherence for femtosecond pulse pumping is discussed in this paper. Finally, the long wavelength edge of SC is beyond 3000�nm when a 1950�nm femtosecond pump pulse propagates in a PCF with negative dispersive slope around the pump pulse. PMID:27534479

  19. Short Wavelength Infrared Hybrid Focal Plane Arrays

    NASA Astrophysics Data System (ADS)

    Vural, K.; Blackwell, J. D...; Marin, E. C.; Edwall, D. D...; Rode, J. P.

    1983-11-01

    Short wavelength (λc = 2.5 μm) 32 x 32 HgCdTe focal plane arrays have been fabricated for use in an Airborne Imaging Spectrometer (AIS) developed by the Jet Propulsion Labora-tory for NASA. An Imaging Spectrometer provides simultaneous imaging of several spectral bands for applications in the sensing and monitoring of earth resources. The detector material is HgCdTe grown on CdTe substrates using liquid phase epitaxy. Planar processing is used to make photovoltaic detectors on 68 um centers. The detector array is mated to a silicon charge coupled device multiplexer to make hybrid focal plane arrays. Results show high performance detectors with a mean RoA = 9.6 x 107 Ω --cm2 and IleakAge (-100 mV) = 0.037 pA at 120K and near zero background. The yield and uniformity are high. The ratio of the standard deviation of the dc responsivity to the mean is 3% for 98.5% of the pixels. The D1.0 = 1.3 x 1012 cm - âœ"fiz/W at a background of 1013 ph/cm2-s and 120K which is close to the background limited (BLIP) D* of 1.9 x 1012 cm- âœ"Hz/W.

  20. Standard reference material 2036 near-infrared reflection wavelength standard.

    PubMed

    Choquette, Steven J; Duewer, David L; Hanssen, Leonard M; Early, Edward A

    2005-04-01

    Standard Reference Material 2036 (SRM 2036) is a certified transfer standard intended for the verification and calibration of the wavelength/wavenumber scale of near-infrared (NIR) spectrometers operating in diffuse or trans-reflectance mode. SRM 2036 Near-Infrared Wavelength/Wavenumber Reflection Standard is a combination of a rare earth oxide glass of a composition similar to that of SRM 2035 Near-Infrared Transmission Wavelength/Wavenumber Standard and SRM 2065 Ultraviolet-Visible-Near-Infrared Transmission Wavelength/Wavenumber Standard, but is in physical contact with a piece of sintered poly(tetrafluoroethylene) (PTFE). The combination of glass contacted with a nearly ideal diffusely reflecting backing provides reflection-absorption bands that range from 15% R to 40% R. SRM 2036 is certified for the 10% band fraction air wavelength centroid location, (10%)B, of seven bands spanning the spectral region from 975 nm to 1946 nm. It is also certified for the vacuum wavenumber (10%)B of the same seven bands in the spectral region from 10 300 cm(-1) to 5130 cm(-1) at 8 cm(-1) resolution. Informational values are provided for the locations of thirteen additional bands from 334 nm to 804 nm. PMID:15901335

  1. Medium-wavelength infrared gas sensing with electrochemically fabricated porous silicon optical rugate filters

    NASA Astrophysics Data System (ADS)

    King, Brian H.; Sailor, Michael J.

    2011-01-01

    Porous silicon optical rugate filters are electrochemically fabricated to display reflectance peaks in the medium-wavelength infrared (MWIR) region from 4 to 8 μm. Etching conditions are adjusted to create filters with single and multiple infrared reflectance peaks overlapping specific infrared chemical absorbance bands. Additional infrared reflectance peaks are designed into the structures to provide internal optical reference channels. Samples containing optical reflectance features matching the absorbance band of CO2 at 2350 cm-1 are used to demonstrate gas sensing with optical filters, and a structure with a photonic stop band tuned to match the infrared absorbance band of the P=O functional group, found in G-series chemical warfare agents, is fabricated. With adequate electrolyte replenishment, the calibrated etch conditions generated reproducible spectral band features even for relatively long etch durations. This work represents the first example of a porous Si spectral filter prepared to match specific spectral features of molecules in the MWIR (``fingerprint'') region.

  2. Extraordinary wavelength reduction in terahertz graphene-cladded photonic crystal slabs

    NASA Astrophysics Data System (ADS)

    Williamson, Ian A. D.; Mousavi, S. Hossein; Wang, Zheng

    2016-05-01

    Photonic crystal slabs have been widely used in nanophotonics for light confinement, dispersion engineering, nonlinearity enhancement, and other unusual effects arising from their structural periodicity. Sub-micron device sizes and mode volumes are routine for silicon-based photonic crystal slabs, however spectrally they are limited to operate in the near infrared. Here, we show that two single-layer graphene sheets allow silicon photonic crystal slabs with submicron periodicity to operate in the terahertz regime, with an extreme 100× wavelength reduction from graphene’s large kinetic inductance. The atomically thin graphene further leads to excellent out-of-plane confinement, and consequently photonic-crystal-slab band structures that closely resemble those of ideal two-dimensional photonic crystals, with broad band gaps even when the slab thickness approaches zero. The overall photonic band structure not only scales with the graphene Fermi level, but more importantly scales to lower frequencies with reduced slab thickness. Just like ideal 2D photonic crystals, graphene-cladded photonic crystal slabs confine light along line defects, forming waveguides with the propagation lengths on the order of tens of lattice constants. The proposed structure opens up the possibility to dramatically reduce the size of terahertz photonic systems by orders of magnitude.

  3. Extraordinary wavelength reduction in terahertz graphene-cladded photonic crystal slabs.

    PubMed

    Williamson, Ian A D; Mousavi, S Hossein; Wang, Zheng

    2016-01-01

    Photonic crystal slabs have been widely used in nanophotonics for light confinement, dispersion engineering, nonlinearity enhancement, and other unusual effects arising from their structural periodicity. Sub-micron device sizes and mode volumes are routine for silicon-based photonic crystal slabs, however spectrally they are limited to operate in the near infrared. Here, we show that two single-layer graphene sheets allow silicon photonic crystal slabs with submicron periodicity to operate in the terahertz regime, with an extreme 100× wavelength reduction from graphene's large kinetic inductance. The atomically thin graphene further leads to excellent out-of-plane confinement, and consequently photonic-crystal-slab band structures that closely resemble those of ideal two-dimensional photonic crystals, with broad band gaps even when the slab thickness approaches zero. The overall photonic band structure not only scales with the graphene Fermi level, but more importantly scales to lower frequencies with reduced slab thickness. Just like ideal 2D photonic crystals, graphene-cladded photonic crystal slabs confine light along line defects, forming waveguides with the propagation lengths on the order of tens of lattice constants. The proposed structure opens up the possibility to dramatically reduce the size of terahertz photonic systems by orders of magnitude. PMID:27143314

  4. Extraordinary wavelength reduction in terahertz graphene-cladded photonic crystal slabs

    PubMed Central

    Williamson, Ian A. D.; Mousavi, S. Hossein; Wang, Zheng

    2016-01-01

    Photonic crystal slabs have been widely used in nanophotonics for light confinement, dispersion engineering, nonlinearity enhancement, and other unusual effects arising from their structural periodicity. Sub-micron device sizes and mode volumes are routine for silicon-based photonic crystal slabs, however spectrally they are limited to operate in the near infrared. Here, we show that two single-layer graphene sheets allow silicon photonic crystal slabs with submicron periodicity to operate in the terahertz regime, with an extreme 100× wavelength reduction from graphene’s large kinetic inductance. The atomically thin graphene further leads to excellent out-of-plane confinement, and consequently photonic-crystal-slab band structures that closely resemble those of ideal two-dimensional photonic crystals, with broad band gaps even when the slab thickness approaches zero. The overall photonic band structure not only scales with the graphene Fermi level, but more importantly scales to lower frequencies with reduced slab thickness. Just like ideal 2D photonic crystals, graphene-cladded photonic crystal slabs confine light along line defects, forming waveguides with the propagation lengths on the order of tens of lattice constants. The proposed structure opens up the possibility to dramatically reduce the size of terahertz photonic systems by orders of magnitude. PMID:27143314

  5. Si infrared pixelless photonic emitter

    NASA Astrophysics Data System (ADS)

    Malyutenko, V. K.; Bogatyrenko, V. V.; Malyutenko, O. Y.; Chyrchyk, S. V.

    2005-09-01

    We report on basic principle and technology of Si high-temperature (T>300K) IR emitter based on all optical down conversion concept. The approach is based on the possibility to modulate semiconductor thermal emission power in the spectral range of intra-band electron transitions through shorter wavelength (inter-band transitions) optical pumping (light down conversion process). Device emission bands are matched to transparency windows in atmosphere (3-5 μm and 8-12 μm) by adjusting thin film coat parameters. The carrier lifetime is responsible for the device time response whereas its maximum power emitted (mW-range) activates with temperature increase. One of the major advantages of devices employing optical "read in" technology is that they are free of contacts and junctions, thus making them ideal for operation at high temperatures.

  6. Silicon photonic device for wavelength sensing and monitoring

    NASA Astrophysics Data System (ADS)

    Vargas Lopez, German R.

    Over the last decade advances and innovations from Silicon Photonics technology were observed in the telecommunications and computing industries. This technology which employs Silicon as an optical medium, relies on current CMOS micro-electronics fabrication processes to enable medium scale integration of many nano-photonic devices to produce photonic integrated circuitry. However, other fields of research such as optical sensor processing can benefit from silicon photonics technology, specially in sensors where the physical measurement is wavelength encoded. In this research work, we present a design and application of a thermally tuned silicon photonic device as an optical sensor interrogator. The main device is a micro-ring resonator filter of 10 mum of diameter. A photonic design toolkit was developed based on open source software from the research community. With those tools it was possible to estimate the resonance and spectral characteristics of the filter. From the obtained design parameters, a 7.8 x 3.8 mm optical chip was fabricated using standard micro-photonics techniques. In order to tune a ring resonance, Nichrome micro-heaters were fabricated on top of the device. Some fabricated devices were systematically characterized and their tuning response were determined. From measurements, a ring resonator with a free-spectral-range of 18.4 nm and with a bandwidth of 0.14 nm was obtained. Using just 5 mA it was possible to tune the device resonance up to 3 nm. In order to apply our device as a sensor interrogator in this research, a model of wavelength estimation using time interval between peaks measurement technique was developed and simulations were carried out to assess its performance. To test the technique, an experiment using a Fiber Bragg grating optical sensor was set, and estimations of the wavelength shift of this sensor due to axial strains yield an error within 22 pm compared to measurements from spectrum analyzer. Results from this study

  7. Sulfonated aluminum phthalocyanines for two-photon photodynamic cancer therapy: the effect of the excitation wavelength

    NASA Astrophysics Data System (ADS)

    Wang, J.; Li, W.; Yu, H. B.; Cheung, N. H.; Chen, J. Y.

    2014-03-01

    Sulfonated aluminum phthalocyanine (AlPcS) is a well-studied photosensitizer which has been widely used in research and in clinical applications of the photodynamic therapy of cancers. Conventionally, one-photon excitation was used, but it was unknown whether two-photon excitation of AlPcS was equally effective. In this study, the two-photon absorption cross sections of AlPcS at near infrared wavelengths were deduced from femtosecond (fs) laser-induced fluorescence. We found that the two-photon absorption cross section of AlPcS was strongly dependent on the excitation wavelength. It was about 19 GM when excited at 800 nm, but grew to 855 GM when excited at 750 nm. The 750 nm fs-laser-induced fluorescence images of AlPcS in human nasopharyngeal carcinoma cells were clearly visible while the corresponding images were very dim when excited at 800 nm. Singlet oxygen production was 13 times higher when excited at 750 nm relative to 800 nm. Our subsequent in vitro experiments showed that 750 nm two-photon excitation with an unfocused fs laser beam damaged cancer cells in a light-dose-dependent manner typical of photodynamic therapy (PDT). The killing at 750 nm was about 9-10 times more efficient than at 800 nm. These results demonstrated for the first time that AlPcS has good potential for two-photon PDT of cancers.

  8. Apparatus for generating coherent infrared energy of selected wavelength

    DOEpatents

    Stevens, C.G.

    A tunable source of coherent infrared energy includes a heat pipe having an intermediate region at which cesium is heated to vaporizing temperature and end regions at which the vapor is condensed and returned to the intermediate region for reheating and recirculation. Optical pumping light is directed along the axis of the heat pipe through a first end window to stimulate emission of coherent infrared energy which is transmitted out through an opposite end window. A porous walled tubulation extends along the axis of the heat pipe and defines a region in which cesium vapor is further heated to a temperature sufficient to dissociate cesium dimers which would decrease efficiency by absorbing pump light. Efficient generation of any desired infrared wavelength is realized by varying the wavelength of the pump light.

  9. Apparatus for generating coherent infrared energy of selected wavelength

    DOEpatents

    Stevens, Charles G.

    1985-01-01

    A tunable source (11) of coherent infrared energy includes a heat pipe (12) having an intermediate region (24) at which cesium (22) is heated to vaporizing temperature and end regions (27, 28) at which the vapor is condensed and returned to the intermediate region (24) for reheating and recirculation. Optical pumping light (43) is directed along the axis of the heat pipe (12) through a first end window (17) to stimulate emission of coherent infrared energy which is transmitted out through an opposite end window (18). A porous walled tubulation (44) extends along the axis of the heat pipe (12) and defines a region (46) in which cesium vapor is further heated to a temperature sufficient to dissociate cesium dimers which would decrease efficiency by absorbing pump light (43). Efficient generation of any desired infrared wavelength is realized by varying the wavelength of the pump light (43).

  10. Stress induced long wavelength photoconductivity in doped silicon infrared detectors

    NASA Technical Reports Server (NTRS)

    Houck, J. R.

    1982-01-01

    The long wavelength cutoff of a Si:P detector was extended to 34 microns by the application of a uniaxial stress. An unstressed Si:P photoconductive detector responds to photons of up to 28 microns wavelength. By applying a uniaxial stress to a detector along the /100/ crystal axis, the response was extended to approximately 34 microns. The /100/ axis was chosen as the stress direction because theoretical calculations predicted that such a stress extends the wavelength response more than one along the /110/ axis. These theoretical calculations were based upon fits to experimental data obtained at stresses of up to approximately kbar, and indicated that the extension in wavelength response continues to increase at much larger stresses.

  11. Ultrabroadband direct detection of nonclassical photon statistics at telecom wavelength.

    PubMed

    Wakui, Kentaro; Eto, Yujiro; Benichi, Hugo; Izumi, Shuro; Yanagida, Tetsufumi; Ema, Kazuhiro; Numata, Takayuki; Fukuda, Daiji; Takeoka, Masahiro; Sasaki, Masahide

    2014-01-01

    Broadband light sources play essential roles in diverse fields, such as high-capacity optical communications, optical coherence tomography, optical spectroscopy, and spectrograph calibration. Although a nonclassical state from spontaneous parametric down-conversion may serve as a quantum counterpart, its detection and characterization have been a challenging task. Here we demonstrate the direct detection of photon numbers of an ultrabroadband (110 nm FWHM) squeezed state in the telecom band centred at 1535 nm wavelength, using a superconducting transition-edge sensor. The observed photon-number distributions violate Klyshko's criterion for the nonclassicality. From the observed photon-number distribution, we evaluate the second- and third-order correlation functions, and characterize a multimode structure, which implies that several tens of orthonormal modes of squeezing exist in the single optical pulse. Our results and techniques open up a new possibility to generate and characterize frequency-multiplexed nonclassical light sources for quantum info-communications technology. PMID:24694515

  12. Ultrabroadband direct detection of nonclassical photon statistics at telecom wavelength

    PubMed Central

    Wakui, Kentaro; Eto, Yujiro; Benichi, Hugo; Izumi, Shuro; Yanagida, Tetsufumi; Ema, Kazuhiro; Numata, Takayuki; Fukuda, Daiji; Takeoka, Masahiro; Sasaki, Masahide

    2014-01-01

    Broadband light sources play essential roles in diverse fields, such as high-capacity optical communications, optical coherence tomography, optical spectroscopy, and spectrograph calibration. Although a nonclassical state from spontaneous parametric down-conversion may serve as a quantum counterpart, its detection and characterization have been a challenging task. Here we demonstrate the direct detection of photon numbers of an ultrabroadband (110 nm FWHM) squeezed state in the telecom band centred at 1535 nm wavelength, using a superconducting transition-edge sensor. The observed photon-number distributions violate Klyshko's criterion for the nonclassicality. From the observed photon-number distribution, we evaluate the second- and third-order correlation functions, and characterize a multimode structure, which implies that several tens of orthonormal modes of squeezing exist in the single optical pulse. Our results and techniques open up a new possibility to generate and characterize frequency-multiplexed nonclassical light sources for quantum info-communications technology. PMID:24694515

  13. Long-Wavelength Infrared (LWIR) Quantum Dot Infrared Photodetector (QDIP) Focal Plane Array

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D.; Bandara, S. V.; Liu, J. K.; Hill, C. J.; Rafol, S. B.; Mumolo, J. M.; Shott, C. A.

    2006-01-01

    We have exploited the artificial atomlike properties of epitaxially self-assembled quantum dots for the development of high operating temperature long wavelength infrared (LWIR) focal plane arrays. Quantum dots are nanometer-scale islands that form spontaneously on a semiconductor substrate due to lattice mismatch. QDIPs are expected to outperform quantum well infrared detectors (QWIPs) and are expected to offer significant advantages over II-VI material based focal plane arrays. QDIPs are fabricated using robust wide bandgap III-V materials which are well suited to the production of highly uniform LWIR arrays. We have used molecular beam epitaxy (MBE) technology to grow multi-layer LWIR quantum dot structures based on the InAs/InGaAs/GaAs material system. JPL is building on its significant QWIP experience and is basically building a Dot-in-the-Well (DWELL) device design by embedding InAs quantum dots in a QWIP structure. This hybrid quantum dot/quantum well device offers additional control in wavelength tuning via control of dot-size and/or quantum well sizes. In addition the quantum wells can trap electrons and aide in ground state refilling. Recent measurements have shown a 10 times higher photoconductive gain than the typical QWIP device, which indirectly confirms the lower relaxation rate of excited electrons (photon bottleneck) in QDPs. Subsequent material and device improvements have demonstrated an absorption quantum efficiency (QE) of approx. 3%. Dot-in-the-well (DWELL) QDIPs were also experimentally shown to absorb both 45 deg. and normally incident light. Thus we have employed a reflection grating structure to further enhance the quantum efficiency. JPL has demonstrated wavelength control by progressively growing material and fabricating devices structures that have continuously increased in LWIR response. The most recent devices exhibit peak responsivity out to 8.1 microns. Peak detectivity of the 8.1 micrometer devices has reached approx. 1 x 10(exp 10

  14. Super sub-wavelength patterns in photon coincidence detection

    NASA Astrophysics Data System (ADS)

    Liu, Ruifeng; Zhang, Pei; Zhou, Yu; Gao, Hong; Li, Fuli

    2014-02-01

    High-precision measurements implemented with light are desired in all fields of science. However, light acts as a wave, and the Rayleigh criterion in classical optics yields a diffraction limit that prevents obtaining a resolution smaller than the wavelength. Sub-wavelength interference has potential application in lithography because it beats the classical Rayleigh resolution limit. Here, we carefully study second-order correlation theory to establish the physics behind sub-wavelength interference in photon coincidence detection. A Young's double slit experiment with pseudo-thermal light is performed to test the second-order correlation pattern. The results show that when two point detectors are scanned in different ways, super sub-wavelength interference patterns can be obtained. We then provide a theoretical explanation for this surprising result, and demonstrate that this explanation is also suitable for the results found for entangled light. Furthermore, we discuss the limitations of these types of super sub-wavelength interference patterns in quantum lithography.

  15. Long-wavelength photonic integrated circuits and avalanche photodetectors

    NASA Astrophysics Data System (ADS)

    Tsou, Yi-Jen D.; Zaytsev, Sergey; Pauchard, Alexandre; Hummel, Steve; Lo, Yu-Hwa

    2001-10-01

    Fast-growing internet traffic volume require high data communication bandwidth over longer distances. Access network bottlenecks put pressure on short-range (SR) telecommunication systems. To effectively address these datacom and telecom market needs, low-cost, high-speed laser modules at 1310 to 1550 nm wavelengths and avalanche photodetectors are required. The great success of GaAs 850nm VCSEls for Gb/s Ethernet has motivated efforts to extend VCSEL technology to longer wavelengths in the 1310 and 1550 nm regimes. However, the technological challenges associated with materials for long wavelength VCSELs are tremendous. Even with recent advances in this area, it is believed that significant additional development is necessary before long wavelength VCSELs that meet commercial specifications will be widely available. In addition, the more stringent OC192 and OC768 specifications for single-mode fiber (SMF) datacom may require more than just a long wavelength laser diode, VCSEL or not, to address numerous cost and performance issues. We believe that photonic integrated circuits (PICs), which compactly integrate surface-emitting lasers with additional active and passive optical components with extended functionality, will provide the best solutions to today's problems. Photonic integrated circuits have been investigated for more than a decade. However, they have produced limited commercial impact to date primarily because the highly complicated fabrication processes produce significant yield and device performance issues. In this presentation, we will discuss a new technology platform of InP-based PICs compatible with surface-emitting laser technology, as well as a high data rate externally modulated laser module. Avalanche photodetectors (APDs) are the key component in the receiver to achieve high data rate over long transmission distance because of their high sensitivity and large gain- bandwidth product. We have used wafer fusion technology to achieve In

  16. Effect of graphene on plasmonic metasurfaces at infrared wavelengths

    SciTech Connect

    Ogawa, Shinpei Fujisawa, Daisuke; Ueno, Masashi

    2013-11-15

    Significant enhancement of infrared transmittance by the presence of a graphene layer on a plasmonic metasurface (PLM) has been demonstrated. PLMs with different configurations were fabricated, and their transmittance with and without graphene was compared. Selective enhancement by graphene occurred at the plasmon resonance wavelength. The degree of enhancement was found to depend on the width of the gap between the periodic metal regions in the PLM. A maximum enhancement of ∼210% was achieved at a wavelength of 10 μm. The ability to achieve such a drastic increase in transmittance at the plasmon resonant wavelength is expected to lead to improvements in the performance of energy collecting devices and optical sensors.

  17. A compact time-resolved system for near infrared spectroscopy based on wavelength space multiplexing

    NASA Astrophysics Data System (ADS)

    Re, Rebecca; Contini, Davide; Caffini, Matteo; Cubeddu, Rinaldo; Spinelli, Lorenzo; Torricelli, Alessandro

    2010-11-01

    We designed and developed a compact dual-wavelength and dual-channel time-resolved system for near-infrared spectroscopy studies of muscle and brain. The system employs pulsed diode lasers as sources, compact photomultipliers, and time-correlated single photon counting boards for detection. To exploit the full temporal and dynamic range of the acquisition technique, we implemented an approach based on wavelength space multiplexing: laser pulses at the two wavelengths are alternatively injected into the two channels by means of an optical 2×2 switch. In each detection line (i.e., in each temporal window), the distribution of photon time-of-flights at one wavelength is acquired. The proposed approach increases the signal-to-noise ratio and avoids wavelength cross-talk with respect to the typical approach based on time multiplexing. The instrument was characterized on tissue phantoms to assess its properties in terms of linearity, stability, noise, and reproducibility. Finally, it was successfully tested in preliminary in vivo measurements on muscle during standard cuff occlusion and on the brain during a motor cortex response due to hand movements.

  18. Detection Wavelength Control of Uncooled Infrared Sensors Using Two-Dimensional Lattice Plasmonic Absorbers †

    PubMed Central

    Takagawa, Yousuke; Ogawa, Shinpei; Kimata, Masafumi

    2015-01-01

    Wavelength-selective uncooled infrared (IR) sensors are highly promising for a wide range of applications, such as fire detection, gas analysis and biomedical analysis. We have recently developed wavelength-selective uncooled IR sensors using square lattice two-dimensional plasmonic absorbers (2-D PLAs). The PLAs consist of a periodic 2-D lattice of Au-based dimples, which allow photons to be manipulated using surface plasmon modes. In the present study, a detailed investigation into control of the detection wavelength was conducted by varying the PLA lattice structure. A comparison was made between wavelength-selective uncooled IR sensors with triangular and square PLA lattices that were fabricated using complementary metal oxide semiconductor and micromachining techniques. Selective enhancement of the responsivity could be achieved, and the detection wavelength for the triangular lattice was shorter than that for the square lattice. The results indicate that the detection wavelength is determined by the reciprocal-lattice vector for the PLAs. The ability to control the detection wavelength in this manner enables the application of such PLAs to many types of thermal IR sensors. The results obtained here represent an important step towards multi-color imaging in the IR region. PMID:26067198

  19. Absolute analytical prediction of photonic crystal guided mode resonance wavelengths

    SciTech Connect

    Hermannsson, Pétur Gordon; Vannahme, Christoph; Smith, Cameron L. C.; Kristensen, Anders

    2014-08-18

    A class of photonic crystal resonant reflectors known as guided mode resonant filters are optical structures that are widely used in the field of refractive index sensing, particularly in biosensing. For the purposes of understanding and design, their behavior has traditionally been modeled numerically with methods such as rigorous coupled wave analysis. Here it is demonstrated how the absolute resonance wavelengths of such structures can be predicted by analytically modeling them as slab waveguides in which the propagation constant is determined by a phase matching condition. The model is experimentally verified to be capable of predicting the absolute resonance wavelengths to an accuracy of within 0.75 nm, as well as resonance wavelength shifts due to changes in cladding index within an accuracy of 0.45 nm across the visible wavelength regime in the case where material dispersion is taken into account. Furthermore, it is demonstrated that the model is valid beyond the limit of low grating modulation, for periodically discontinuous waveguide layers, high refractive index contrasts, and highly dispersive media.

  20. A single-photon detector in the far-infrared range

    PubMed

    Komiyama; Astafiev; Antonov; Kutsuwa; Hirai

    2000-01-27

    The far-infrared region (wavelengths in the range 10 microm-1 mm) is one of the richest areas of spectroscopic research, encompassing the rotational spectra of molecules and vibrational spectra of solids, liquids and gases. But studies in this spectral region are hampered by the absence of sensitive detectors--despite recent efforts to improve superconducting bolometers, attainable sensitivities are currently far below the level of single-photon detection. This is in marked contrast to the visible and near-infrared regions (wavelengths shorter than about 1.5 microm), in which single-photon counting is possible using photomultiplier tubes. Here we report the detection of single far-infrared photons in the wavelength range 175-210 microm (6.0-7.1 meV), using a single-electron transistor consisting of a semiconductor quantum dot in high magnetic field. We detect, with a time resolution of a millisecond, an incident flux of 0.1 photons per second on an effective detector area of 0.1 mm2--a sensitivity that exceeds previously reported values by a factor of more than 10(4). The sensitivity is a consequence of the unconventional detection mechanism, in which one absorbed photon leads to a current of 10(6)-10(12) electrons through the quantum dot. By contrast, mechanisms of conventional detectors or photon assisted tunnelling in single-electron transistors produce only a few electrons per incident photon. PMID:10667787

  1. Wavelength division demultiplexing with photonic crystal self-collimation interference

    NASA Astrophysics Data System (ADS)

    Wang, Yufei; Qiu, Yishen; Chen, Xiyao; Lin, Guimin; Hong, Hailian

    2007-11-01

    A theoretical model of wavelength division demultiplexer (WDD), which is based on an asymmetric Mach-Zehnder interferometer (AMZI) constructed in a two-dimensional photonic crystal (2D PhC), is proposed and numerically demonstrated. The 2D PhC consists of a square lattice of cylindric air holes in silicon. The AMZI includes two mirrors and two splitters. Lights propagate between them employing self-collimation effect. The two interferometer branches have different path lengths. By using the finite-difference time-domain method, the calculation results show that the transmission spectras at two AMZI output ports are in the shape of sinusoidal curves and have a uniform peak spacing in the frequency range from 0.26c/a to 0.27c/a. When the path length of the longer branch is increased and the shorter one is fixed, the peaks shift to the lower frequencies and the peak spacing decreases nonlinearly. Consequently, the transmission can be designed to meet various application demands by changing the length difference between the two branches. For the dimensions of the WDD are about tens of operating wavelengths, this PhC WDD may be applied in future photonic integrated circuits.

  2. Electrically tunable zero dispersion wavelengths in photonic crystal fibers filled with a dual frequency addressable liquid crystal

    SciTech Connect

    Wahle, Markus Kitzerow, Heinz-Siegfried

    2015-11-16

    We present a liquid crystal (LC) infiltrated photonic crystal fiber, which enables the electrical tuning of the position of zero dispersion wavelengths (ZDWs). A dual frequency addressable liquid crystal is aligned perpendicular on the inclusion walls of a photonic crystal fiber, which results in an escaped radial director field. The orientation of the LC is controlled by applying an external electric field. Due to the high index of the liquid crystal the fiber guides light by the photonic band gap effect. Multiple ZDWs exist in the visible and near infrared. The positions of the ZDWs can be either blue or red shifted depending on the frequency of the applied voltage.

  3. Electrically tunable zero dispersion wavelengths in photonic crystal fibers filled with a dual frequency addressable liquid crystal

    NASA Astrophysics Data System (ADS)

    Wahle, Markus; Kitzerow, Heinz-Siegfried

    2015-11-01

    We present a liquid crystal (LC) infiltrated photonic crystal fiber, which enables the electrical tuning of the position of zero dispersion wavelengths (ZDWs). A dual frequency addressable liquid crystal is aligned perpendicular on the inclusion walls of a photonic crystal fiber, which results in an escaped radial director field. The orientation of the LC is controlled by applying an external electric field. Due to the high index of the liquid crystal the fiber guides light by the photonic band gap effect. Multiple ZDWs exist in the visible and near infrared. The positions of the ZDWs can be either blue or red shifted depending on the frequency of the applied voltage.

  4. Group IV photonics for the mid infrared

    NASA Astrophysics Data System (ADS)

    Soref, Richard

    2013-02-01

    This paper outlines the challenges and benefits of applying silicon-based photonic techniques in the 2 to 5 μm midinfrared (MIR) wavelength range for chem.-bio-physical sensing, medical diagnostics, industrial process control, environmental monitoring, secure communications, Ladar, active imaging, and high-speed communications at 2 μm. Onchip passive and active components, mostly waveguided, will enable opto-electronic CMOS or BiCMOS integrated "circuits" for system-on-a-chip applications such as spectroscopy and lab-on-a-chip. Volume manufacture in a silicon foundry is expected to yield low-cost (or even disposable) chips with benefits in size-weight-power and ruggedness. This is "long-wavelength optoelectronic integration on silicon" which we call LIOS. Room temperature operation appears feasible, albeit with performance compromises at 4 to 5 μm. In addition to the electronics layer (which may include RF wireless), a 3-D LIOS chip can include several inter-communicating layers utilizing the photonic, plasmonic, photoniccrystal and opto-electro-mechanical technologies. The LIOS challenge can be met by (1) discovering new physics, (2) employing "new" IV and III-V alloys, (3) scaling-up and modifying telecom components, and (4) applying nonlinearoptical wavelength conversion in some cases. This paper presents proposals for MIR chip spectrometers employing frequency-comb and Ge blackbody sources. Active heterostructures employing Si, Ge, SiGe, GeSn and SiGeSn are key for laser diodes, photodetectors, LEDs, switches, amplifiers, and modulators that provide totally monolithic foundry integration, while numerous III-V semiconductor MIR devices within the InGaAsSb and InGaAsP families offer practical hybrid integration on Si PICs. Interband cascade and quantum cascade lasers on Ge waveguides are important in this context.

  5. Optically guided neuronal growth at near-infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Stevenson, D. J.; Lake, T. K.; Agate, B.; Garcés-Chávez, V.; Dholakia, K.; Gunn-Moore, F.

    2006-08-01

    Recent work has indicated the potential of light to guide the growth cones of neuronal cells using a Ti:Sapphire laser at 800 nm (Ehrlicher et al, PNAS, 2002). We have developed an optical set-up that has allowed, for the first time, the direct comparison of this process at near infrared wavelengths. A high number of growth cones were studied in order to provide a detailed statistical analysis. Actively extending growth cones of the neuroblastoma cell-line, NG108, can be guided at not only 780 nm, but also at 1064 nm. These wavelengths are an appropriate choice for guidance experiments, as wavelengths in the visible spectrum and UV are highly absorbing by cells and lead to death by phototoxicity and thermal stress. At 780 nm, 47% of actively extending growth cones were found to turn towards the focused incident light by at least 30° (n=32 growth cones). At 1064 nm, 61% of cells were successfully guided (n=31 growth cones). This suggests that the light detection mechanism within the cell is not due a single protein with a defined activity wavelength as occurs for example with the photoreceptor family of opsin proteins in the mammalian eye. We present two novel mechanisms of light induced neuronal guidance which are not related to temperature increases, or optical tweezing of the growth cone. We are also now identifying the signaling pathways that mediate this phenomenon.

  6. Promising new wavelengths for multi-photon microscopy: thinking outside the Ti:Sapphire box

    NASA Astrophysics Data System (ADS)

    Norris, Greg; Amor, Rumelo; Dempster, John; Amos, William B.; McConnell, Gail

    2013-02-01

    Multi-photon excitation (MPE) imaging is dominated by the Ti:Sapphire laser as the source for excitation. However, it is limited when considering 3PE of common fluorophores and efficient 2PE of UV dyes which require wavelengths beyond the range of the Ti:Sapphire. Two ultra-short pulsed sources are presented as alternatives: a novel optical parametric oscillator (OPO) geometry (1400-1600nm) and the sum-frequency mixing of an OPO and Yb-doped fibre laser, providing a tunable output (626-635nm). For long wavelengths, we report three-photon laser scanning microscopy (3PLSM) using a bi-directional pumped optical parametric oscillator (OPO) with signal wavelength output at 1500 nm. This novel laser was used to overcome the high optical loss in the infrared spectral region observed in laser scanning microscopes and objective lenses that renders them otherwise difficult to use for imaging. To test our system, we performed 3PLSM auto-fluorescence imaging of live plant cells at 1500 nm, specifically Spirogyra, and compared performance with two-photon excitation (2PLSM) imaging using a femtosecond pulsed Ti:Sapphire laser at 780 nm. Analysis of cell viability based on cytoplasmic organelle streaming and structural changes of cells revealed that at similar peak powers, 2PLSM caused gross cell damage after 5 minutes but 3PLSM showed little or no interference with cell function after 15 minutes. The 1500 nm OPO was thus shown to be a practical laser source for live cell imaging. For short wavelengths, we report the use of an all-solid-state ultra-short pulsed source specifically for two-photon microscopy at wavelengths shorter than those of the conventional Ti:Sapphire laser. Our approach involved sumfrequency mixing of the output from the long-wavelength OPO described above with residual pump radiation to generate fs-pulsed output in the red spectral region. We demonstrated the performance of our ultra-short pulsed system using fluorescently labelled and autofluorescent tissue

  7. Variable CO2 laser attenuator. [for infrared wavelengths

    NASA Technical Reports Server (NTRS)

    Klein, B. J.; Degnan, J. J.; Walker, H. E.; Zagwodzki, T.

    1974-01-01

    An infrared wavelength variable attenuator based on contra-rotating germanium wedges is examined theoretically. The device redirects the paths of internal reflections associated with an optical flat to avoid closely spaced parallel beams at the output. Complementary wedges separated by an air gap compose an optical flat which, when combined with a masking arrangement, restricts unwanted reflections. A model of the device was built and experimentally evaluated. The results compare favorably with the dynamic range of attenuation of 2 to 50 db from theoretical calculations, and show a substantial reduction in the etalon effect associated with pairs of optical flats.

  8. Astronomical imaging Fourier spectroscopy at far-infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Naylor, David A.; Gom, Brad G.; van der Wiel, Matthijs H. D.; Makiwa, Gibion

    2013-11-01

    The principles and practice of astronomical imaging Fourier transform spectroscopy (FTS) at far-infrared wavelengths are described. The Mach–Zehnder (MZ) interferometer design has been widely adopted for current and future imaging FTS instruments; we compare this design with two other common interferometer formats. Examples of three instruments based on the MZ design are presented. The techniques for retrieving astrophysical parameters from the measured spectra are discussed using calibration data obtained with the Herschel–SPIRE instrument. The paper concludes with an example of imaging spectroscopy obtained with the SPIRE FTS instrument.

  9. Germanium-on-SOI waveguides for mid-infrared wavelengths.

    PubMed

    Younis, Usman; Vanga, Sudheer K; Lim, Andy Eu-Jin; Lo, Patrick Guo-Qiang; Bettiol, Andrew A; Ang, Kah-Wee

    2016-05-30

    We report on the development of Germanium-on-SOI waveguides for mid-infrared wavelengths. The strip waveguides have been formed in 0.85 and 2 μm thick Ge grown on SOI substrate with 220 nm thick Si overlayer. The propagation loss for various waveguide widths has been measured using the Fabry-Perot method with temperature tuning. The minimum loss of ~8 dB/cm has been achieved for 0.85 μm thick Ge core using 3.682 μm laser excitation. The transparency of these waveguides has been measured up to at least 3.82 μm. PMID:27410120

  10. Few-photon-level two-dimensional infrared imaging by coincidence frequency upconversion

    NASA Astrophysics Data System (ADS)

    Huang, Kun; Gu, Xiaorong; Pan, Haifeng; E Wu, Zeng, Heping

    2012-04-01

    We demonstrate few-photon-level infrared imaging at 1040 nm by coincidence frequency upconversion with a high conversion efficiency of 33.5%. By synchronous pulse pumping at 1549 nm, the infrared object image was spectrally upconverted into the visible regime. The upconverted image was captured by a silicon electron multiplying charged coupled device without any scanning devices, thus gaining in simplicity and speed. The imaging sensitivity was improved by reducing the background noise with coincidence pulsed pumping at long wavelength.

  11. High Operating Temperature Barrier Infrared Detector with Tailorable Cutoff Wavelength

    NASA Technical Reports Server (NTRS)

    Ting, David Z. (Inventor); Hill, Cory J. (Inventor); Seibel, Alexander (Inventor); Bandara, Sumith Y. (Inventor); Gunapala, Sarath D. (Inventor)

    2015-01-01

    A barrier infrared detector with absorber materials having selectable cutoff wavelengths and its method of manufacture is described. A GaInAsSb absorber layer may be grown on a GaSb substrate layer formed by mixing GaSb and InAsSb by an absorber mixing ratio. A GaAlAsSb barrier layer may then be grown on the barrier layer formed by mixing GaSb and AlSbAs by a barrier mixing ratio. The absorber mixing ratio may be selected to adjust a band gap of the absorber layer and thereby determine a cutoff wavelength for the barrier infrared detector. The absorber mixing ratio may vary along an absorber layer growth direction. Various contact layer architectures may be used. In addition, a top contact layer may be isolated into an array of elements electrically isolated as individual functional detectors that may be used in a detector array, imaging array, or focal plane array.

  12. Photonic crystal lasers using wavelength-scale embedded active region

    NASA Astrophysics Data System (ADS)

    Matsuo, Shinji; Sato, Tomonari; Takeda, Koji; Shinya, Akihiko; Nozaki, Kengo; Kuramochi, Eiichi; Taniyama, Hideaki; Notomi, Masaya; Fujii, Takuro; Hasebe, Koichi; Kakitsuka, Takaaki

    2014-01-01

    Lasers with ultra-low operating energy are desired for use in chip-to-chip and on-chip optical interconnects. If we are to reduce the operating energy, we must reduce the active volume. Therefore, a photonic crystal (PhC) laser with a wavelength-scale cavity has attracted a lot of attention because a PhC provides a large Q-factor with a small volume. To improve this device's performance, we employ an embedded active region structure in which the wavelength-scale active region is buried with an InP PhC slab. This structure enables us to achieve effective confinement of both carriers and photons, and to improve the thermal resistance of the device. Thus, we have obtained a large external differential quantum efficiency of 55% and an output power of -10 dBm by optical pumping. For electrical pumping, we use a lateral p-i-n structure that employs Zn diffusion and Si ion implantation for p-type and n-type doping, respectively. We have achieved room-temperature continuous-wave operation with a threshold current of 7.8 µA and a maximum 3 dB bandwidth of 16.2 GHz. The results of an experimental bit error rate measurement with a 10 Gbit s-1 NRZ signal reveal the minimum operating energy for transferring a single bit of 5.5 fJ. These results show the potential of this laser to be used for very short reach interconnects. We also describe the optimal design of cavity quality (Q) factor in terms of achieving a large output power with a low operating energy using a calculation based on rate equations. When we assume an internal absorption loss of 20 cm-1, the optimized coupling Q-factor is 2000.

  13. A Kind of Double-Cladding Photonic Crystal Fiber with High Birefringence and Two Zero-Dispersion Wavelengths

    NASA Astrophysics Data System (ADS)

    Zhou, Hong-Song; Li, Shu-Guang; Fu, Bo; Yao, Yan-Yan; Zhang, Lei

    2010-01-01

    A kind of double-cladding photonic crystal fiber (DC-PCF) with high birefringence and two zero-dispersion wavelengths is proposed. It is found that the birefringence of DC-PCF with inner cladding air holes pitch 1.0 μm and diameter 0.8 μm is 1.001 × 10-2 in the optical communication band at wavelength 1.55 μm by the multipole method. It is demonstrated that two zero dispersion wavelengths can be achieved in the optical communication band between 0.8 μm and 1.7 μm, and the first zero-dispersion wavelength is in the working wave band of the Ti:sapphire oscillator, which contributes to the frequency conversion of the Ti:sapphire femtosecond laser. PCF with two zero-dispersion wavelengths can make strong power supercontinuum spectral in the near infrared band.

  14. Bridging visible and telecom wavelengths with a single-mode broadband photon pair source

    SciTech Connect

    Soeller, C.; Brecht, B.; Mosley, P. J.; Zang, L. Y.; Podlipensky, A.; Joly, N. Y.; Russell, P. St. J.; Silberhorn, C.

    2010-03-15

    We present a spectrally decorrelated photon pair source bridging the visible and telecom wavelength regions. Tailored design and fabrication of a solid-core photonic crystal fiber (PCF) lead to the emission of signal and idler photons into only a single spectral and spatial mode. Thus no narrowband filtering is necessary and the heralded generation of pure photon number states in ultrafast wave packets at telecom wavelengths becomes possible.

  15. Travelling-wave single-photon detectors integrated with diamond photonic circuits: operation at visible and telecom wavelengths with a timing jitter down to 23 ps

    NASA Astrophysics Data System (ADS)

    Rath, Patrik; Vetter, Andreas; Kovalyuk, Vadim; Ferrari, Simone; Kahl, Oliver; Nebel, Christoph; Goltsman, Gregory N.; Korneev, Alexander; Pernice, Wolfram H. P.

    2016-02-01

    We report on the design, fabrication and measurement of travelling-wave superconducting nanowire single-photon detectors (SNSPDs) integrated with polycrystalline diamond photonic circuits. We analyze their performance both in the near-infrared wavelength regime around 1600 nm and at 765 nm. Near-IR detection is important for compatibility with the telecommunication infrastructure, while operation in the visible wavelength range is relevant for compatibility with the emission line of silicon vacancy centers in diamond which can be used as efficient single-photon sources. Our detectors feature high critical currents (up to 31 μA) and high performance in terms of efficiency (up to 74% at 765 nm), noise-equivalent power (down to 4.4×10-19 W/Hz1/2 at 765 nm) and timing jitter (down to 23 ps).

  16. Interference with a quantum dot single-photon source and a laser at telecom wavelength

    SciTech Connect

    Felle, M.; Huwer, J. Stevenson, R. M.; Skiba-Szymanska, J.; Ward, M. B.; Shields, A. J.; Farrer, I.; Ritchie, D. A.; Penty, R. V.

    2015-09-28

    The interference of photons emitted by dissimilar sources is an essential requirement for a wide range of photonic quantum information applications. Many of these applications are in quantum communications and need to operate at standard telecommunication wavelengths to minimize the impact of photon losses and be compatible with existing infrastructure. Here, we demonstrate for the first time the quantum interference of telecom-wavelength photons from an InAs/GaAs quantum dot single-photon source and a laser; an important step towards such applications. The results are in good agreement with a theoretical model, indicating a high degree of indistinguishability for the interfering photons.

  17. Infrared FEL photochemistry: Multiple-photon dissociation of freon gas

    NASA Astrophysics Data System (ADS)

    Newnam, B. E.; Early, J. W.; Lyman, J. L.

    Wavelength tunability, synchrotron sidebands, and picosecond pulse structure are inherent FEL characteristics that should be advantageous for photochemistry involving infrared multiple-photon photodissociation. Tuned to an absorption resonance, the FEL sideband structure will overlap the broad, excited-state spectral absorption and should lead to enhanced dissociation. The Los Alamos APEX FEL was operated with and without sidebands to test this hypothesis on CFCl3 (Freon 11), an inert chlorofluorocarbon widely used in refrigeration systems and one of the gases implicated as depleting the ozone in the Earth's stratospheric layer. The FEL wavelength was set at the C-Cl stretch absorption resonance at 11.8-microns, the oscillator cavity length was detuned first to minimize and then to maximize the spectral bandwidth, and the beam was focused through a pair of test cells (1.0 Torr Freon + 1.7 Torr air). Comparison of final and initial absorbance spectra indicated the CFCl3 photodissociation yield was 1.2% for the cell exposed with sideband spectra (3% FWHM) and 9-ns micropulse separation. Negligible effect was seen without sidebands, albeit at lower total beam fluence. Although the result of this single experiment is not large enough to be conclusive, it does provide a basis for optimizing the FEL temporal and spectral parameters to attain higher photodissociation yield in future tests.

  18. Widely Wavelength-Tunable Blue-Shifted Dispersive Waves for Broadband Visible Wavelength Generation in a Photonic Crystal Fiber Cladding

    NASA Astrophysics Data System (ADS)

    Yuan, Jin-Hui; Sang, Xin-Zhu; Yu, Chong-Xiu; Shen, Xiang-Wei; Wang, Kui-Ru; Yan, Bin-Bin; Han, Ying; Zhou, Gui-Yao; Hou, Lan-Tian

    2012-10-01

    Blue-shifted dispersive waves (DWs) are efficiently generated from the red-shifted solitons by coupling the 120 fs pulses into the fundamental mode of the multi-knots of a photonic crystal fiber cladding. When the femtosecond pulses at the wavelength of 825 nm and the average power of 300 mW are coupled into knots 1-3, the conversion efficiency ηDW of 32% and bandwidth BDW of 50 nm are obtained. The ultrashort pulses generated by the DWs can be tunable over the whole visible wavelength by adjusting the wavelengths of the pump pulses coupled into different knots. It can be believed that this widely wavelength-tunable ultrashort visible pulse source has important applications in ultrafast photonics and resonant Raman scattering.

  19. Linkage and Anomeric Differentiation in Trisaccharides by Sequential Fragmentation and Variable-Wavelength Infrared Photodissociation

    NASA Astrophysics Data System (ADS)

    Tan, Yanglan; Polfer, Nicolas C.

    2015-02-01

    Carbohydrates and their derivatives play important roles in biological systems, but their isomeric heterogeneity also presents a considerable challenge for analytical techniques. Here, a stepwise approach using infrared multiple-photon dissociation (IRMPD) via a tunable CO2 laser (9.2-10.7 μm) was employed to characterize isomeric variants of glucose-based trisaccharides. After the deprotonated trisaccharides were trapped and fragmented to disaccharide C2 fragments in a Fourier transform ion cyclotron resonance (FTICR) cell, a further variable-wavelength infrared irradiation of the C2 ion produced wavelength-dependent dissociation patterns that are represented as heat maps. The photodissociation patterns of these C2 fragments are shown to be strikingly similar to the photodissociation patterns of disaccharides with identical glycosidic bonds. Conversely, the photodissociation patterns of different glycosidic linkages exhibit considerable differences. On the basis of these results, the linkage position and anomericity of glycosidic bonds of disaccharide units in trisaccharides can be systematically differentiated and identified, providing a promising approach to characterize the structures of isomeric oligosaccharides.

  20. Linkage and anomeric differentiation in trisaccharides by sequential fragmentation and variable-wavelength infrared photodissociation.

    PubMed

    Tan, Yanglan; Polfer, Nicolas C

    2015-02-01

    Carbohydrates and their derivatives play important roles in biological systems, but their isomeric heterogeneity also presents a considerable challenge for analytical techniques. Here, a stepwise approach using infrared multiple-photon dissociation (IRMPD) via a tunable CO2 laser (9.2-10.7 μm) was employed to characterize isomeric variants of glucose-based trisaccharides. After the deprotonated trisaccharides were trapped and fragmented to disaccharide C2 fragments in a Fourier transform ion cyclotron resonance (FTICR) cell, a further variable-wavelength infrared irradiation of the C2 ion produced wavelength-dependent dissociation patterns that are represented as heat maps. The photodissociation patterns of these C2 fragments are shown to be strikingly similar to the photodissociation patterns of disaccharides with identical glycosidic bonds. Conversely, the photodissociation patterns of different glycosidic linkages exhibit considerable differences. On the basis of these results, the linkage position and anomericity of glycosidic bonds of disaccharide units in trisaccharides can be systematically differentiated and identified, providing a promising approach to characterize the structures of isomeric oligosaccharides. PMID:25492690

  1. Uncooled infrared photon detector and multicolor infrared detection using microoptomechanical sensors

    DOEpatents

    Datskos, Panagiotis G.; Rajic, Solobodan; Datskou, Irene C.

    1999-01-01

    Systems and methods for infrared detection are described. An optomechanical photon detector includes a semiconductor material and is based on measurement of a photoinduced lattice strain. A multicolor infrared sensor includes a stack of frequency specific optomechanical detectors. The stack can include one, or more, of the optomechanical photon detectors that function based on the measurement of photoinduced lattice strain. The systems and methods provide advantages in that rapid, sensitive multicolor infrared imaging can be performed without the need for a cooling subsystem.

  2. Long-wavelength infrared hyperspectral data "mining" at Cuprite, NV

    NASA Astrophysics Data System (ADS)

    Sundberg, Robert; Adler-Golden, Steven; Conforti, Patrick

    2015-09-01

    In recent years long-wavelength infrared (LWIR) hyperspectral imagery has significantly improved in quality and become much more widely available, sparking interest in a variety of applications involving remote sensing of surface composition. This in turn has motivated the development and study of LWIR-focused algorithms for atmospheric retrieval, temperature-emissivity separation (TES) and material detection and identification. In this paper we evaluate some LWIR algorithms for atmospheric retrieval, TES, endmember-finding and rare material detection for their utility in characterizing mineral composition in SEBASS hyperspectral imagery taken near Cuprite, NV. Atmospheric correction results using the In-Scene Atmospheric Correction (ISAC) method are compared with those from the first-principles, MODTRAN©-based FLAASH-IR method. Covariance-whitened endmember-finding methods are observed to be sensitive to image artifacts. However, with clean data and all-natural terrain they can automatically locate and distinguish many minor mineral components, with especially high sensitivity to varieties of calcite. Not surprisingly, the major scene materials, including silicates, are best located using unwhitened techniques. Minerals that we identified in the data include calcite, quartz, alunite and (tentatively) kaolinite.

  3. The appearance of dusty H II blisters at radio and infrared wavelengths

    NASA Technical Reports Server (NTRS)

    Icke, V.; Gatley, I.; Israel, F. P.

    1980-01-01

    Detailed calculations for the observational appearance of nonspherical Stromgren regions at radio and infrared wavelengths are presented. The computations are made feasible by two assumptions, namely (1) no stellar photon leaves the solid angle within which it was emitted, and (2) the radiation spectrum can be represented by three delta functions corresponding to Lyman continuum, Lyman alpha, and softer radiation. These calculations are used to develop models for the H II blisters M17 A and 30 Doradus, and also first order parameters for a sample of other well-studied galactic H II regions. It is concluded that the observations are well explained by an ionizing object in a density gradient, without the need for peculiar dust properties or distribution.

  4. Two-photon interference at telecom wavelengths for time-bin-encoded single photons from quantum-dot spin qubits.

    PubMed

    Yu, Leo; Natarajan, Chandra M; Horikiri, Tomoyuki; Langrock, Carsten; Pelc, Jason S; Tanner, Michael G; Abe, Eisuke; Maier, Sebastian; Schneider, Christian; Höfling, Sven; Kamp, Martin; Hadfield, Robert H; Fejer, Martin M; Yamamoto, Yoshihisa

    2015-01-01

    Practical quantum communication between remote quantum memories rely on single photons at telecom wavelengths. Although spin-photon entanglement has been demonstrated in atomic and solid-state qubit systems, the produced single photons at short wavelengths and with polarization encoding are not suitable for long-distance communication, because they suffer from high propagation loss and depolarization in optical fibres. Establishing entanglement between remote quantum nodes would further require the photons generated from separate nodes to be indistinguishable. Here, we report the observation of correlations between a quantum-dot spin and a telecom single photon across a 2-km fibre channel based on time-bin encoding and background-free frequency downconversion. The downconverted photon at telecom wavelengths exhibits two-photon interference with another photon from an independent source, achieving a mean wavepacket overlap of greater than 0.89 despite their original wavelength mismatch (900 and 911 nm). The quantum-networking operations that we demonstrate will enable practical communication between solid-state spin qubits across long distances. PMID:26597223

  5. Two-photon interference at telecom wavelengths for time-bin-encoded single photons from quantum-dot spin qubits

    PubMed Central

    Yu, Leo; Natarajan, Chandra M.; Horikiri, Tomoyuki; Langrock, Carsten; Pelc, Jason S.; Tanner, Michael G.; Abe, Eisuke; Maier, Sebastian; Schneider, Christian; Höfling, Sven; Kamp, Martin; Hadfield, Robert H.; Fejer, Martin M.; Yamamoto, Yoshihisa

    2015-01-01

    Practical quantum communication between remote quantum memories rely on single photons at telecom wavelengths. Although spin-photon entanglement has been demonstrated in atomic and solid-state qubit systems, the produced single photons at short wavelengths and with polarization encoding are not suitable for long-distance communication, because they suffer from high propagation loss and depolarization in optical fibres. Establishing entanglement between remote quantum nodes would further require the photons generated from separate nodes to be indistinguishable. Here, we report the observation of correlations between a quantum-dot spin and a telecom single photon across a 2-km fibre channel based on time-bin encoding and background-free frequency downconversion. The downconverted photon at telecom wavelengths exhibits two-photon interference with another photon from an independent source, achieving a mean wavepacket overlap of greater than 0.89 despite their original wavelength mismatch (900 and 911 nm). The quantum-networking operations that we demonstrate will enable practical communication between solid-state spin qubits across long distances. PMID:26597223

  6. Two-photon interference at telecom wavelengths for time-bin-encoded single photons from quantum-dot spin qubits

    NASA Astrophysics Data System (ADS)

    Yu, Leo; Natarajan, Chandra M.; Horikiri, Tomoyuki; Langrock, Carsten; Pelc, Jason S.; Tanner, Michael G.; Abe, Eisuke; Maier, Sebastian; Schneider, Christian; Höfling, Sven; Kamp, Martin; Hadfield, Robert H.; Fejer, Martin M.; Yamamoto, Yoshihisa

    2015-11-01

    Practical quantum communication between remote quantum memories rely on single photons at telecom wavelengths. Although spin-photon entanglement has been demonstrated in atomic and solid-state qubit systems, the produced single photons at short wavelengths and with polarization encoding are not suitable for long-distance communication, because they suffer from high propagation loss and depolarization in optical fibres. Establishing entanglement between remote quantum nodes would further require the photons generated from separate nodes to be indistinguishable. Here, we report the observation of correlations between a quantum-dot spin and a telecom single photon across a 2-km fibre channel based on time-bin encoding and background-free frequency downconversion. The downconverted photon at telecom wavelengths exhibits two-photon interference with another photon from an independent source, achieving a mean wavepacket overlap of greater than 0.89 despite their original wavelength mismatch (900 and 911 nm). The quantum-networking operations that we demonstrate will enable practical communication between solid-state spin qubits across long distances.

  7. Photonic crystal fibre enables short-wavelength two-photon laser scanning fluorescence microscopy with fura-2

    NASA Astrophysics Data System (ADS)

    McConnell, Gail; Riis, Erling

    2004-10-01

    We report on a novel and compact reliable laser source capable of short-wavelength two-photon laser scanning fluorescence microscopy based on soliton self-frequency shift effects in photonic crystal fibre. We demonstrate the function of the system by performing two-photon microscopy of smooth muscle cells and cardiac myocytes from the rat pulmonary vein and Chinese hamster ovary cells loaded with the fluorescent calcium indicator fura-2/AM.

  8. Nonlinear silicon photonics from the near to mid infrared

    NASA Astrophysics Data System (ADS)

    Park, Jung Soo

    This dissertation presents experimental work investigating silicon-on-insulator (SOI) photonic waveguides for parametric nonlinear optic devices. An introduction is presented in Chapter 1, including background and motivation for exploring SOI as a platform for integrated photonics, as well as an overview of integrated nonlinear optic devices. Chapter 2 discusses on-chip slow light structures based on coupled-resonator optical waveguides (CROW), potentially useful for enhancing nonlinearities for efficient chip-scale nonlinear optics. Although slowing light is limited by fabrication tolerance-induced disorder, a fundamental phenomenon is observed: the Anderson localization of optical waves. Chapter 3 of the dissertation discusses four-wave mixing in SOI waveguides. SOI waveguide fabrication is described in detail, including achieving low fiber-to-chip coupling loss and waveguide propagation loss. Two approaches for dispersion engineering are presented: with the design of waveguide dimensions and with a thin-film cladding. Parametric wavelength conversion by degenerate (single-pump) FWM in these dispersion-engineered waveguides is demonstrated and discussed. Chapter 4 concerns FWM with two pumps, an approach that promises functionalities not possible with a single pump such as multiple sideband generation with self-seeded higher-order pumps. In addition to demonstrating the generation of up to ten sidebands with dual pumps and subsequent self-seeded higher order pumps, we characterize trade-offs in maximum conversion efficiency due to nondegenerate two-photon absorption (TPA). The work presented in Chapter 5 takes a novel approach to SOI parametric devices by exploring a new spectral range, toward the mid-infrared (mid-IR), near 2 mum and beyond. We measure FWM in silicon waveguides with a pump near 2 mum, which itself is generated by the parametric conversion of a 1300 nm seed by a 1589 nm pump in a highly-nonlinear fiber (HNLF). Fundamentally, our results show

  9. Micropolarizing device for long wavelength infrared polarization imaging.

    SciTech Connect

    Wendt, Joel Robert; Carter, Tony Ray; Samora, Sally; Cruz-Cabrera, Alvaro Augusto; Vawter, Gregory Allen; Kemme, Shanalyn A.; Alford, Charles Fred; Boye, Robert R.; Smith, Jody Lynn

    2006-11-01

    The goal of this project is to fabricate a four-state pixelated subwavelength optical device that enables mid-wave infrared (MWIR) or long-wave infrared (LWIR) snapshot polarimetric imaging. The polarization information can help to classify imaged materials and identify objects of interest for numerous remote sensing and military applications. While traditional, sequential polarimetric imaging produces scenes with polarization information through a series of assembled images, snapshot polarimetric imaging collects the spatial distribution of all four Stokes parameters simultaneously. In this way any noise due to scene movement from one frame to the next is eliminated. We fabricated several arrays of subwavelength components for MWIR polarization imaging applications. Each pixel unit of the array consists of four elements. These elements are micropolarizers with three or four different polarizing axis orientations. The fourth element sometimes has a micro birefringent waveplate on the top of one of the micropolarizers. The linear micropolarizers were fabricated by patterning nano-scale metallic grids on a transparent substrate. A large area birefringent waveplate was fabricated by deeply etching a subwavelength structure into a dielectric substrate. The principle of making linear micropolarizers for long wavelengths is based upon strong anisotropic absorption of light in the nano-metallic grid structures. The nano-metallic grid structures are patterned with different orientations; therefore, the micropolarizers have different polarization axes. The birefringent waveplate is a deeply etched dielectric one-dimensional subwavelength grating; therefore two orthogonally polarized waves have different phase delays. Finally, in this project, we investigated the near field and diffractive effects of the subwavelength element apertures upon detection. The fabricated pixelated polarizers had a measured extinction ratios larger than 100:1 for pixel sizes in the order of 15

  10. A 640 X 512-Pixel Portable Long-Wavelength Infrared Camera

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath; Bandara, Sumith; Liu, John; Rafol, Sir B.

    2007-01-01

    A portable long-wavelength infrared electronic camera having a cutoff wavelength of 9 microns has been built around an image sensor in the form of a 640X512-pixel array of AlxGa(1-x)As/GaAs quantum-well infrared photodetectors (QWIPs). This camera is an intermediate product of a continuing program to develop high-resolution, high-sensitivity infrared cameras.

  11. Fabrication and properties of metalo-dielectric photonic crystal structures for infrared spectral region.

    PubMed

    Mizeikis, Vygantas; Juodkazis, Saulius; Tarozaite, Rima; Juodkazyte, Jurga; Juodkazis, Kestutis; Misawa, Hiroaki

    2007-06-25

    We report structural and optical properties of three-dimensional periodic metallic woodpile structures obtained by direct laser writing in dielectric photoresist SU-8 and subsequent electroless coating by a thin Ni film. Signatures of photonic stop gaps were observed in optical reflection spectra of the structures at infrared wavelengths. This study demonstrates that the combination of DLW and chemical infiltration of metals is attractive as a simple and cost-efficient method for the fabrication of metalo-dielectric photonic crystals. PMID:19547177

  12. Research of thermal cycles of long wavelength MCT infrared detectors

    NASA Astrophysics Data System (ADS)

    Wu, Li-gang; Liu, Da-fu; Zhu, San-gen; Gong, Hai-mei

    2009-07-01

    The conflict of longevity of satellite's service and limited life of Sterling cooler decides that coolers should work on the intermittent mode in space. As a result, The HgCdTe (MCT) infrared (IR) detectors in satellite are commonly subjected to thousands of repeated thermal cycles from below -173°C to room temperature (20°C), which brings some new reliability problems. Especially the mismatch of coefficient of thermal expansion (CTE) of different materials may lead to some unfamiliar failure modes with such low temperature and nearly 200°C span of thermal cycles. In order to study the characteristics of MCT detectors under the stress of thermal cycles, this paper introduced a special automatic system. The system is mainly composed of a sub-container of liquid nitrogen, a heater controlled by the PID hardware, and an object stage on which the MCT detectors to be tested are mounted. Furthermore, the sub-container, the heater and the stage are positioned in a large vacuum tank. In the course of thermal cycles, the object stage moved up and down with MCT detectors is driven by a step motor. When it rises to the bottom of liquid nitrogen sub-container, the stage is to be cooled with detectors, and when declines to the heater, the stage to be heated with detectors, too. At last, two long wavelength MCT detector samples are tested with this equipment, and the resistance, the signal and the noise are measured. It shows that all the pixels' resistance didn't change beyond 5% after 5000 cycles. However, the tested signal of the last pixel of both detectors increased sharply after 1000 cycles, and fell to normal level after 5000 cycles, with its noise altering a little from beginning to end. A deduction is given in this paper for this phenomenon. In accordance, the thermal cycle equipment and the experimental data, would supply some references to the design and fabrication of MCT IR detectors.

  13. Efficient generation of twin photons at telecom wavelengths with 2.5 GHz repetition-rate-tunable comb laser.

    PubMed

    Jin, Rui-Bo; Shimizu, Ryosuke; Morohashi, Isao; Wakui, Kentaro; Takeoka, Masahiro; Izumi, Shuro; Sakamoto, Takahide; Fujiwara, Mikio; Yamashita, Taro; Miki, Shigehito; Terai, Hirotaka; Wang, Zhen; Sasaki, Masahide

    2014-01-01

    Efficient generation and detection of indistinguishable twin photons are at the core of quantum information and communications technology (Q-ICT). These photons are conventionally generated by spontaneous parametric down conversion (SPDC), which is a probabilistic process, and hence occurs at a limited rate, which restricts wider applications of Q-ICT. To increase the rate, one had to excite SPDC by higher pump power, while it inevitably produced more unwanted multi-photon components, harmfully degrading quantum interference visibility. Here we solve this problem by using recently developed 10 GHz repetition-rate-tunable comb laser, combined with a group-velocity-matched nonlinear crystal, and superconducting nanowire single photon detectors. They operate at telecom wavelengths more efficiently with less noises than conventional schemes, those typically operate at visible and near infrared wavelengths generated by a 76 MHz Ti Sapphire laser and detected by Si detectors. We could show high interference visibilities, which are free from the pump-power induced degradation. Our laser, nonlinear crystal, and detectors constitute a powerful tool box, which will pave a way to implementing quantum photonics circuits with variety of good and low-cost telecom components, and will eventually realize scalable Q-ICT in optical infra-structures. PMID:25524646

  14. Improved performance of HgCdTe infrared detector focal plane arrays by modulating light field based on photonic crystal structure

    SciTech Connect

    Liang, Jian; Hu, Weida Ye, Zhenhua; Li, Zhifeng; Chen, Xiaoshuang Lu, Wei; Liao, Lei

    2014-05-14

    An HgCdTe long-wavelength infrared focal plane array photodetector is proposed by modulating light distributions based on the photonic crystal. It is shown that a promising prospect of improving performance is better light harvest and dark current limitation. To optimize the photon field distributions of the HgCdTe-based photonic crystal structure, a numerical method is built by combining the finite-element modeling and the finite-difference time-domain simulation. The optical and electrical characteristics of designed HgCdTe mid-wavelength and long-wavelength photon-trapping infrared detector focal plane arrays are obtained numerically. The results indicate that the photon crystal structure, which is entirely compatible with the large infrared focal plane arrays, can significantly reduce the dark current without degrading the quantum efficiency compared to the regular mesa or planar structure.

  15. Integration of both dense wavelength-division multiplexing and coarse wavelength-division multiplexing demultiplexer on one photonic crystal chip

    NASA Astrophysics Data System (ADS)

    Tian, Huiping; Shen, Guansheng; Liu, Weijia; Ji, Yuefeng

    2013-07-01

    An integrated model of photonic crystal (PC) demultiplexer that can be used to combine dense wavelength-division multiplexing (DWDM) and coarse wavelength-division multiplexing (CWDM) systems is first proposed. By applying the PC demultiplexer, dense channel spacing 0.8 nm and coarse channel spacing 20 nm are obtained at the same time. The transmission can be improved to nearly 90%, and the crosstalk can be decreased to less than -18 dB by enlarging the width of the bus waveguide. The total size of the device is 21×42 μm2. Four channels on one side of the demultiplexer can achieve DWDM in the wavelength range between 1575 and 1578 nm, and the other four channels on the other side can achieve CWDM in the wavelength range between 1490 and 1565 nm, respectively. The demonstrated demultiplexer can be applied in the future CWDM and DWDM system, and the architecture costs can be significantly reduced.

  16. Observational Studies of Protoplanetary Disks at Mid-Infrared Wavelengths

    NASA Astrophysics Data System (ADS)

    Li, Dan; Telesco, Charles; Wright, Christopher; Packham, Christopher; Marinas, Naibi

    2013-07-01

    We have used mid-infrared cameras on 8-to-10 m class telescopes to study the properties of young circumstellar disks. During the initial phases of this program we examined a large sample of mid-IR images of standard stars delivered by T-ReCS at Gemini South to evaluate its on-sky performance as characterized by, for example the angular resolution, the PSF shape, and the PSF temporal stability, properties that are most relevant to our high-angular resolution study of disks. With this information we developed an Interactive Data Language (IDL) package of routines optimized for reducing the data and correcting for image defects commonly seen in ground-based mid-IR data. We obtained, reduced, and analyzed mid-IR images and spectra of several Herbig Ae/Be disks (including HD 259431, MWC 1080, VV Ser) and the debris disk (β Pic), and derived their physical properties by means of radiative transfer modeling or spectroscopic decomposition and analyses. These results are highlighted here. During this study, we also helped commission CanariCam, a new mid-IR facility instrument built by the University of Florida for the 10.4 m Gran Telescopio Canarias (GTC) on La Palma, Canary Islands, Spain. CanariCam is an imager with spectroscopic, polarimetric, and coronagraphic capabilities, with the dual-beam polarimetry being a unique mode introduced with CanariCam for the first time to a 10 m telescope at mid-IR wavelengths. It is well known that measurements of polarization, originating from aligned dust grains in the disks and their environments, have the potential to shed light on the morphologies of the magnetic fields in these regions, information that is critical to understanding how stars and planets form. We have obtained polarimetric data of several Herbig Ae/Be disks and YSOs, and the data reduction and analyses are in process. We present preliminary results here. This poster is based upon work supported by the NSF under grant AST-0903672 and AST-0908624 awarded to C.M.T.

  17. Polymer lattices as mechanically tunable 3-dimensional photonic crystals operating in the infrared

    SciTech Connect

    Chernow, V. F.; Alaeian, H.; Dionne, J. A.; Greer, J. R.

    2015-09-07

    Broadly tunable photonic crystals in the near- to mid-infrared region could find use in spectroscopy, non-invasive medical diagnosis, chemical and biological sensing, and military applications, but so far have not been widely realized. We report the fabrication and characterization of three-dimensional tunable photonic crystals composed of polymer nanolattices with an octahedron unit-cell geometry. These photonic crystals exhibit a strong peak in reflection in the mid-infrared that shifts substantially and reversibly with application of compressive uniaxial strain. A strain of ∼40% results in a 2.2 μm wavelength shift in the pseudo-stop band, from 7.3 μm for the as-fabricated nanolattice to 5.1 μm when strained. We found a linear relationship between the overall compressive strain in the photonic crystal and the resulting stopband shift, with a ∼50 nm blueshift in the reflection peak position per percent increase in strain. These results suggest that architected nanolattices can serve as efficient three-dimensional mechanically tunable photonic crystals, providing a foundation for new opto-mechanical components and devices across infrared and possibly visible frequencies.

  18. Polymer lattices as mechanically tunable 3-dimensional photonic crystals operating in the infrared

    NASA Astrophysics Data System (ADS)

    Chernow, V. F.; Alaeian, H.; Dionne, J. A.; Greer, J. R.

    2015-09-01

    Broadly tunable photonic crystals in the near- to mid-infrared region could find use in spectroscopy, non-invasive medical diagnosis, chemical and biological sensing, and military applications, but so far have not been widely realized. We report the fabrication and characterization of three-dimensional tunable photonic crystals composed of polymer nanolattices with an octahedron unit-cell geometry. These photonic crystals exhibit a strong peak in reflection in the mid-infrared that shifts substantially and reversibly with application of compressive uniaxial strain. A strain of ˜40% results in a 2.2 μm wavelength shift in the pseudo-stop band, from 7.3 μm for the as-fabricated nanolattice to 5.1 μm when strained. We found a linear relationship between the overall compressive strain in the photonic crystal and the resulting stopband shift, with a ˜50 nm blueshift in the reflection peak position per percent increase in strain. These results suggest that architected nanolattices can serve as efficient three-dimensional mechanically tunable photonic crystals, providing a foundation for new opto-mechanical components and devices across infrared and possibly visible frequencies.

  19. 1024 x 1024 pixel mid-wavelength and long-wavelength infrared QWIP focal plane arrays for imaging applications

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Hill, C. J.; Rafol, S. B.; Mumolo, J. M.; Trinh, J. T.; Tidrow, M. Z.; LeVan, P. D.

    2005-01-01

    Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 10(24) x 10(24) pixel quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NEAT) of 17 mK at a 95 K operating temperature with f/2.5 optics at 300 K background and the LWIR detector array has demonstrated a NEAT of 13 mK at a 70 K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90 K and 70 K operating temperatures respectively, with similar optical and background conditions. In this paper, we will discuss the performance in terms of quantum efficiency, NE(delta)T, uniformity, operability and modulation transfer functions.

  20. Efficient generation of indistinguishable single photons on-demand at telecom wavelengths

    NASA Astrophysics Data System (ADS)

    Kim, Jehyung; Cai, Tao; Richardson, Christopher; Leavitt, Richard; Waks, Edo

    Highly efficient single photon sources are important building blocks for optical quantum information processing. For practical use and long-distance quantum communication, single photons should have fiber-compatible telecom wavelengths. In addition, most quantum communication applications require high degree of indistinguishability of single photons, such that they exhibit interference on a beam splitter. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem in particular at telecom wavelengths. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. To obtain the efficient single quantum dot emission, we employ the higher order mode in L3 photonic crystal cavity that shows a nearly Gaussian transverse mode profile and results in out-coupling efficiency exceeding 46 % and unusual bright single quantum dot emission exceeding 1.5 million counts per second at a detector. We also observe Purcell enhanced spontaneous emission rate as large as 4 and high linear polarization ratio of 0.96 for the coupled dots. Using this source, we generate high purity single photons at 1.3 μm wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement.

  1. High quantum efficiency mid-wavelength interband cascade infrared photodetectors with one and two stages

    NASA Astrophysics Data System (ADS)

    Zhou, Yi; Chen, Jianxin; Xu, Zhicheng; He, Li

    2016-08-01

    In this paper, we report on mid-wavelength infrared interband cascade photodetectors grown on InAs substrates. We studied the transport properties of the photon-generated carriers in the interband cascade structures by comparing two different detectors, a single stage detector and a two-stage cascade detector. The two-stage device showed quantum efficiency around 19.8% at room temperature, and clear optical response was measured even at a temperature of 323 K. The two detectors showed similar Johnson-noise limited detectivity. The peak detectivity of the one- and two-stage devices was measured to be 2.15 × 1014 cm·Hz1/02/W and 2.19 × 1014 cm·Hz1/02/W at 80 K, 1.21 × 109 cm·Hz1/02/W and 1.23 × 109 cm·Hz1/02/W at 300 K, respectively. The 300 K background limited infrared performance (BLIP) operation temperature is estimated to be over 140 K.

  2. Algol - CPNG: photon counting cameras for interferometry in visible wavelengths

    NASA Astrophysics Data System (ADS)

    Blazit, A.; Thiébaut, E.; Vakili, F.; Abe, L.; Spang, A.; Clausse, J.-M.; Mourard, D.; Foy, R.; Rondeau, X.

    Images in visible interferometry are characterised by their low coherence time, and except for brightest stars, the flux on the detector is much less than one photon per pixel per image. Algol and Comptage de Photons Nouvelle Génération (CPNG) are new photon counting cameras developed for high angular resolution in the visible. They are intensified CCDs built to benefit from improvements in photonic commercial components, and personal computer processing power. We present how we achieve optimal performances (sensitivity and spatiotemporal resolution) by the combination of proper optical and electronics design, and real-time elaborated data processing. The number of pixels is 532× 516 and 768× 640 read at a frame rate of 262 Hz and 50 Hz for CPNG and Algol respectively. The dark current is very low: 5×10-4 electron.pixel-1.s-1. Quantum efficiencies reach up to 36% in the visible with the GaAsP photocathodes and and 26% in the red with the GaAs ones, thanks to the sensitivity of the photocathodes and to the photon centroiding algorithm; they are likely the highest values reported for ICCDs.

  3. Heterogeneous quantum dot/silicon photonics-based wavelength-tunable laser diode with a 44 nm wavelength-tuning range

    NASA Astrophysics Data System (ADS)

    Kita, Tomohiro; Yamamoto, Naokatsu; Matsumoto, Atsushi; Kawanishi, Tetsuya; Yamada, Hirohito

    2016-04-01

    A heterogeneous wavelength-tunable laser diode combining quantum dot and silicon photonics technologies is proposed. A compact wavelength-tunable filter with two ring resonators was carefully designed and fabricated using silicon photonics technology. The tunable laser combining the wavelength-tunable filter and an optical amplifier, which includes InAs quantum dots, achieved a 44.0 nm wavelength-tuning range at around 1250 nm. The broadband optical gain of the quantum dot optical amplifier was effectively used by the optimized wavelength-tunable filter. This heterogeneous wavelength-tunable laser diode could become a breakthrough technology for high-capacity data transmission systems.

  4. Visible-wavelength two-photon excitation microscopy for fluorescent protein imaging.

    PubMed

    Yamanaka, Masahito; Saito, Kenta; Smith, Nicholas I; Arai, Yoshiyuki; Uegaki, Kumiko; Yonemaru, Yasuo; Mochizuki, Kentaro; Kawata, Satoshi; Nagai, Takeharu; Fujita, Katsumasa

    2015-10-01

    The simultaneous observation of multiple fluorescent proteins (FPs) by optical microscopy is revealing mechanisms by which proteins and organelles control a variety of cellular functions. Here we show the use of visible-light based two-photon excitation for simultaneously imaging multiple FPs. We demonstrated that multiple fluorescent targets can be concurrently excited by the absorption of two photons from the visible wavelength range and can be applied in multicolor fluorescence imaging. The technique also allows simultaneous single-photon excitation to offer simultaneous excitation of FPs across the entire range of visible wavelengths from a single excitation source. The calculation of point spread functions shows that the visible-wavelength two-photon excitation provides the fundamental improvement of spatial resolution compared to conventional confocal microscopy. PMID:26238663

  5. Visible-wavelength two-photon excitation microscopy for fluorescent protein imaging

    NASA Astrophysics Data System (ADS)

    Yamanaka, Masahito; Saito, Kenta; Smith, Nicholas I.; Arai, Yoshiyuki; Uegaki, Kumiko; Yonemaru, Yasuo; Mochizuki, Kentaro; Kawata, Satoshi; Nagai, Takeharu; Fujita, Katsumasa

    2015-10-01

    The simultaneous observation of multiple fluorescent proteins (FPs) by optical microscopy is revealing mechanisms by which proteins and organelles control a variety of cellular functions. Here we show the use of visible-light based two-photon excitation for simultaneously imaging multiple FPs. We demonstrated that multiple fluorescent targets can be concurrently excited by the absorption of two photons from the visible wavelength range and can be applied in multicolor fluorescence imaging. The technique also allows simultaneous single-photon excitation to offer simultaneous excitation of FPs across the entire range of visible wavelengths from a single excitation source. The calculation of point spread functions shows that the visible-wavelength two-photon excitation provides the fundamental improvement of spatial resolution compared to conventional confocal microscopy.

  6. Stacked silicide/silicon mid- to long-wavelength infrared detector

    DOEpatents

    Maserjian, Joseph

    1990-03-13

    The use of stacked Schottky barriers (16) with epitaxially grown thin silicides (10) combined with selective doping (22) of the barriers provides high quantum efficiency infrared detectors (30) at longer wavelengths that is compatible with existing silicon VLSI technology.

  7. Doping-Spike PtSi Schottky Infrared Detectors with Extended Cutoff Wavelengths

    NASA Technical Reports Server (NTRS)

    Lin, T. L.; Park, J. S.; Gunapala, S. D.; Jones, E. W.; Castillo, H. M. Del

    1994-01-01

    A technique incorporating a p+ doping spike at the silicide/Si interface to reduce the effective Schottky barrier of the silicide infrared detectors and thus extend the cutoff wavelength has been developed.

  8. A photonic crystal waveguide with silicon on insulator in the near-infrared band

    NASA Astrophysics Data System (ADS)

    Tang, Hai-Xia; Zuo, Yu-Hua; Yu, Jin-Zhong; Wang, Qi-Ming

    2007-07-01

    A two-dimensional (2D) photonic crystal waveguide in the Γ-K direction with triangular lattice on a silicon-on-insulator (SOI) substrate in the near-infrared band is fabricated by the combination of electron beam lithography and inductively coupled plasma etching. Its transmission characteristics are analysed from the stimulated band diagram by the effective index and the 2D plane wave expansion (PWE) methods. In the experiment, the transmission band edge in a longer wavelength of the photonic crystal waveguide is about 1590 nm, which is in good qualitative agreement with the simulated value. However, there is a disagreement between the experimental and the simulated results when the wavelength ranges from 1607 to 1630 nm, which can be considered as due to the unpolarized source used in the transmission measurement.

  9. Design of MWIR Type-II Superlattices for Infrared Photon Detectors

    NASA Astrophysics Data System (ADS)

    Grein, Christoph

    The Type II InAs/GaInSb and InAs/InAsSb superlattices are material systems for implementation as photodetector absorbers in infrared imaging applications. In addition to cutoff wavelengths spanning the infrared spectrum, they offer degrees of freedom in their materials design (e.g. layer thicknesses, alloy compositions, number of layers in one superlattice period) that permit the optimization of an infrared photon detector's figures of merit such as detectivity through the tuning of material properties like generation/recombination lifetimes and optical absorption. We describe efforts to obtain accurate electronic band structures of superlattice semiconductors with infrared energy gaps, and employing them to evaluate nonradiative minority carrier lifetimes. Simple device models are utilized to suggest potential performance enhancements that arise from employing superlattices as infrared absorber. We also discuss current efforts to simulate the molecular beam epitaxial growth of InAs/InAsSb superlattices to predict dominant native point defects and other growth nonidealities. Design of MWIR Type-II Superlattices for Infrared Photon Detectors.

  10. Omnidirectional wavelength selective emitters/absorbers based on dielectric-filled anti-reflection coated two-dimensional metallic photonic crystals

    NASA Astrophysics Data System (ADS)

    Yeng, Yi Xiang; Chou, Jeffrey B.; Rinnerbauer, Veronika; Shen, Yichen; Kim, Sang-Gook; Joannopoulos, John D.; Soljačić, Marin; Čelanović, Ivan

    2014-08-01

    We demonstrate designs of dielectric-filled anti-reflection coated (ARC) two-dimensional (2D) metallic photonic crystals (MPhCs) capable of omnidirectional, polarization insensitive, wavelength selective emission/absorption. Up to 26% improvement in hemispherically averaged emittance/absorptance below the cutoff wavelength is observed for optimized hafnium oxide filled 2D tantalum (Ta) PhCs over the unfilled 2D Ta PhCs. The optimized designs possess high hemispherically averaged emittance/absorptance of 0.86 at wavelengths below the cutoff wavelength and low hemispherically averaged emittance/absorptance of 0.12 at wavelengths above the cutoff wavelength, which is extremely promising for applications such as thermophotovoltaic energy conversion, solar absorption, and infrared spectroscopy.

  11. On the Determination of the Emission Wavelength of an Infrared LED with Common Laboratory Instruments

    ERIC Educational Resources Information Center

    RayChaudhuri, Barun

    2011-01-01

    This work demonstrates an experiment on the optoelectronic properties of a p-n junction suitable for students of undergraduate physics. It investigates, from an educational point of view, the origin of the wavelength of radiation emitted by a light emitting diode (LED) and determines the emission wavelength of an infrared LED without using…

  12. Near infrared quadruple wavelength spectrophotometry of the rat head.

    PubMed

    Hazeki, O; Tamura, M

    1989-01-01

    A quadruple wavelength method to monitor the changes in concentration of oxygenated and deoxygenated hemoglobin and the redox state of cytochrome oxidase within a living tissue is presented. The expected advantages of this technique over the triple wavelength method are (i) that it can compensate for the light scattering change of tissue itself or for instabilities of light source and photomultiplier, (ii) that it can treat the optical properties of the red blood cell in a tissue in the same way as in an in vitro model system, and (iii) that it requires no estimation of the absorption coefficient of cytochrome oxidase in situ. PMID:2551140

  13. Wavelength scaling of efficient high-order harmonic generation by two-color infrared laser fields

    SciTech Connect

    Lan Pengfei; Takahashi, Eiji J.; Midorikawa, Katsumi

    2010-06-15

    We theoretically investigate and demonstrate a better wavelength scaling of harmonic yield in a two-color infrared field. By mixing a Ti:sapphire assistant field with the infrared driving field, we show that high harmonic generation is enhanced and the harmonic yield scales as {lambda}{sup -3}-{lambda}{sup -4} in the plateau region, which falls more slowly as the increase of the driving laser wavelength {lambda} compared with {lambda}{sup -5}-{lambda}{sup -6} in a one-color infrared field.

  14. Detection range enhancement using circularly polarized light in scattering environments for infrared wavelengths

    DOE PAGESBeta

    van der Laan, J. D.; Sandia National Lab.; Scrymgeour, D. A.; Kemme, S. A.; Dereniak, E. L.

    2015-03-13

    We find for infrared wavelengths there are broad ranges of particle sizes and refractive indices that represent fog and rain where the use of circular polarization can persist to longer ranges than linear polarization. Using polarization tracking Monte Carlo simulations for varying particle size, wavelength, and refractive index, we show that for specific scene parameters circular polarization outperforms linear polarization in maintaining the intended polarization state for large optical depths. This enhancement with circular polarization can be exploited to improve range and target detection in obscurant environments that are important in many critical sensing applications. Specifically, circular polarization persists bettermore » than linear for radiation fog in the short-wave infrared, for advection fog in the short-wave infrared and the long-wave infrared, and large particle sizes of Sahara dust around the 4 micron wavelength.« less

  15. Detection range enhancement using circularly polarized light in scattering environments for infrared wavelengths

    SciTech Connect

    van der Laan, J. D.; Scrymgeour, D. A.; Kemme, S. A.; Dereniak, E. L.

    2015-03-13

    We find for infrared wavelengths there are broad ranges of particle sizes and refractive indices that represent fog and rain where the use of circular polarization can persist to longer ranges than linear polarization. Using polarization tracking Monte Carlo simulations for varying particle size, wavelength, and refractive index, we show that for specific scene parameters circular polarization outperforms linear polarization in maintaining the intended polarization state for large optical depths. This enhancement with circular polarization can be exploited to improve range and target detection in obscurant environments that are important in many critical sensing applications. Specifically, circular polarization persists better than linear for radiation fog in the short-wave infrared, for advection fog in the short-wave infrared and the long-wave infrared, and large particle sizes of Sahara dust around the 4 micron wavelength.

  16. Photonic nonlinear transient computing with multiple-delay wavelength dynamics.

    PubMed

    Martinenghi, Romain; Rybalko, Sergei; Jacquot, Maxime; Chembo, Yanne K; Larger, Laurent

    2012-06-15

    We report on the experimental demonstration of a hybrid optoelectronic neuromorphic computer based on a complex nonlinear wavelength dynamics including multiple delayed feedbacks with randomly defined weights. This neuromorphic approach is based on a new paradigm of a brain-inspired computational unit, intrinsically differing from Turing machines. This recent paradigm consists in expanding the input information to be processed into a higher dimensional phase space, through the nonlinear transient response of a complex dynamics excited by the input information. The computed output is then extracted via a linear separation of the transient trajectory in the complex phase space. The hyperplane separation is derived from a learning phase consisting of the resolution of a regression problem. The processing capability originates from the nonlinear transient, resulting in nonlinear transient computing. The computational performance is successfully evaluated on a standard benchmark test, namely, a spoken digit recognition task. PMID:23004274

  17. Photonic Nonlinear Transient Computing with Multiple-Delay Wavelength Dynamics

    NASA Astrophysics Data System (ADS)

    Martinenghi, Romain; Rybalko, Sergei; Jacquot, Maxime; Chembo, Yanne K.; Larger, Laurent

    2012-06-01

    We report on the experimental demonstration of a hybrid optoelectronic neuromorphic computer based on a complex nonlinear wavelength dynamics including multiple delayed feedbacks with randomly defined weights. This neuromorphic approach is based on a new paradigm of a brain-inspired computational unit, intrinsically differing from Turing machines. This recent paradigm consists in expanding the input information to be processed into a higher dimensional phase space, through the nonlinear transient response of a complex dynamics excited by the input information. The computed output is then extracted via a linear separation of the transient trajectory in the complex phase space. The hyperplane separation is derived from a learning phase consisting of the resolution of a regression problem. The processing capability originates from the nonlinear transient, resulting in nonlinear transient computing. The computational performance is successfully evaluated on a standard benchmark test, namely, a spoken digit recognition task.

  18. Nonlinear wavelength conversion in photonic crystal fibers with three zero-dispersion points

    SciTech Connect

    Stark, S. P.; Biancalana, F.; Podlipensky, A.; St. J. Russell, P.

    2011-02-15

    In this theoretical study, we show that a simple endlessly single-mode photonic crystal fiber can be designed to yield, not just two, but three zero-dispersion wavelengths. The presence of a third dispersion zero creates a rich phase-matching topology, enabling enhanced control over the spectral locations of the four-wave-mixing and resonant-radiation bands emitted by solitons and short pulses. The greatly enhanced flexibility in the positioning of these bands has applications in wavelength conversion, supercontinuum generation, and pair-photon sources for quantum optics.

  19. Wavelength-tunable entangled photons from silicon-integrated III–V quantum dots

    PubMed Central

    Chen, Yan; Zhang, Jiaxiang; Zopf, Michael; Jung, Kyubong; Zhang, Yang; Keil, Robert; Ding, Fei; Schmidt, Oliver G.

    2016-01-01

    Many of the quantum information applications rely on indistinguishable sources of polarization-entangled photons. Semiconductor quantum dots are among the leading candidates for a deterministic entangled photon source; however, due to their random growth nature, it is impossible to find different quantum dots emitting entangled photons with identical wavelengths. The wavelength tunability has therefore become a fundamental requirement for a number of envisioned applications, for example, nesting different dots via the entanglement swapping and interfacing dots with cavities/atoms. Here we report the generation of wavelength-tunable entangled photons from on-chip integrated InAs/GaAs quantum dots. With a novel anisotropic strain engineering technique based on PMN-PT/silicon micro-electromechanical system, we can recover the quantum dot electronic symmetry at different exciton emission wavelengths. Together with a footprint of several hundred microns, our device facilitates the scalable integration of indistinguishable entangled photon sources on-chip, and therefore removes a major stumbling block to the quantum-dot-based solid-state quantum information platforms. PMID:26813326

  20. Wavelength-tunable entangled photons from silicon-integrated III-V quantum dots

    NASA Astrophysics Data System (ADS)

    Chen, Yan; Zhang, Jiaxiang; Zopf, Michael; Jung, Kyubong; Zhang, Yang; Keil, Robert; Ding, Fei; Schmidt, Oliver G.

    2016-01-01

    Many of the quantum information applications rely on indistinguishable sources of polarization-entangled photons. Semiconductor quantum dots are among the leading candidates for a deterministic entangled photon source; however, due to their random growth nature, it is impossible to find different quantum dots emitting entangled photons with identical wavelengths. The wavelength tunability has therefore become a fundamental requirement for a number of envisioned applications, for example, nesting different dots via the entanglement swapping and interfacing dots with cavities/atoms. Here we report the generation of wavelength-tunable entangled photons from on-chip integrated InAs/GaAs quantum dots. With a novel anisotropic strain engineering technique based on PMN-PT/silicon micro-electromechanical system, we can recover the quantum dot electronic symmetry at different exciton emission wavelengths. Together with a footprint of several hundred microns, our device facilitates the scalable integration of indistinguishable entangled photon sources on-chip, and therefore removes a major stumbling block to the quantum-dot-based solid-state quantum information platforms.

  1. Wavelength-tunable entangled photons from silicon-integrated III-V quantum dots.

    PubMed

    Chen, Yan; Zhang, Jiaxiang; Zopf, Michael; Jung, Kyubong; Zhang, Yang; Keil, Robert; Ding, Fei; Schmidt, Oliver G

    2016-01-01

    Many of the quantum information applications rely on indistinguishable sources of polarization-entangled photons. Semiconductor quantum dots are among the leading candidates for a deterministic entangled photon source; however, due to their random growth nature, it is impossible to find different quantum dots emitting entangled photons with identical wavelengths. The wavelength tunability has therefore become a fundamental requirement for a number of envisioned applications, for example, nesting different dots via the entanglement swapping and interfacing dots with cavities/atoms. Here we report the generation of wavelength-tunable entangled photons from on-chip integrated InAs/GaAs quantum dots. With a novel anisotropic strain engineering technique based on PMN-PT/silicon micro-electromechanical system, we can recover the quantum dot electronic symmetry at different exciton emission wavelengths. Together with a footprint of several hundred microns, our device facilitates the scalable integration of indistinguishable entangled photon sources on-chip, and therefore removes a major stumbling block to the quantum-dot-based solid-state quantum information platforms. PMID:26813326

  2. Fabrication and characterization of silicon woodpile photonic crystals with a complete bandgap at telecom wavelengths.

    PubMed

    Staude, I; Thiel, M; Essig, S; Wolff, C; Busch, K; von Freymann, G; Wegener, M

    2010-04-01

    By using direct laser writing into a novel commercially available photoresist and a silicon-double-inversion procedure followed by tempering of the silicon structures, we realize high-quality centered-tetragonal woodpile photonic crystals with complete photonic bandgaps near 1.55 microm wavelength. The 6.9% gap-to-midgap ratio bandgap is evidenced by the comparison of measured transmittance and reflectance spectra with band-structure and scattering-matrix calculations. PMID:20364228

  3. Methods and devices for maintaining a resonant wavelength of a photonic microresonator

    DOEpatents

    Jones, Adam; Zortman, William A.

    2015-07-14

    A photonic microresonator incorporates a localized heater element within a section of an optical bus waveguide that is in proximity to the resonator structure. The application of an adjustable control voltage to the heater element provides a localized change in the refractive index value of the bus waveguide, compensating for temperature-induced wavelength drift and maintaining a stabilized value of the microresonator's resonant wavelength.

  4. Towards linear optical detection with single photon sensitivity at telecom wavelengths

    NASA Astrophysics Data System (ADS)

    Jahanmirinejad, Saeedeh; Fiore, Andrea

    2012-06-01

    Standard linear optical detectors have a maximum sensitivity in the few hundreds of photons range, limited by amplifier noise. On the other hand, single photon detectors, which are the most sensitive detectors, are strongly nonlinear: One or more photons result in the same output signal. Photon number resolving (PNR) detectors, which have the ability to discriminate the number of photons in a weak optical pulse, are of great importance in the field of quantum information processing and quantum cryptography. Moreover, a PNR detector with large dynamic range can cover the gap between these two detection modes. Such detectors are greatly desirable not only in quantum information science and technology, but also in any application dealing with low light levels. In this work, we propose a novel approach to photon number resolving detectors based on spatial multiplexing of nanowire superconducting single-photon detectors. In the proposed approach, N superconducting nanowires, each connected in parallel to an integrated resistor, are connected in series. Photon absorption in a nanowire switches its bias current to the parallel resistor, forming a voltage pulse across it. The sum of these voltages, proportional to the number of absorbed photons, is measured at the output. The use of a cryogenic preamplifier with high input impedance for the read-out increases the linearity, the signal to noise ratio, and the speed. With this combination, we expect to be able to count up to few tens of photons with high fidelity, excellent timing resolution, and very high sensitivity in the telecommunication wavelength range.

  5. Infrared Avionics Signal Distribution using Wavelength Division Multiplexing

    NASA Technical Reports Server (NTRS)

    Atiquzzaman, Mohammed; Sluss, Jim; Nguyen, Hung; Ngo, Duc

    2003-01-01

    Pilots in the cockpits of aircrafts currently communicate with ground stations using Radio Frequency (RF) signals. Antennas mounted outside the aircraft receive and transmit RF signals from and to the ground stations. The RF signals received at the antennas are sent to the cockpit using coaxial cables. As the number of antennas needed to provide more than one frequency band in aircrafts increases, RF distribution media (such as coaxial cable) adds to the complexity and weight of the cockpit wiring. Concomitantly, the safety and signal to noise ratio also decreases due to the use of RF signals. The University of Oklahoma is collaborating with the National Aeronautics and Space Administration to develop optical fiber based schemes to replace the coaxial cable used for RF signal distribution within an aircraft. The project aims at exploiting emerging Wavelength Division Multiplexing (WDM) techniques to reduce the weight of cabling, and increase the signal to noise ratio and reliability. This will be achieved by wavelength division multiplexing the signals from the various antennas and then demultiplexing the signals to recover the original signals at the cockpit. This paper will show that (i) RF signals can not only be wavelength multiplexed at the end of a fiber, but additional signals can be inserted into the middle of the fiber using WDM technology, and (ii) the signals can also be successfully extracted by tapping into the middle of the fiber. We are currently extending our previous laboratory prototype (which could multiplex signals only at the end of the fiber) to include additional multiplexing and demultiplexing of RF signals from the middle of the optical backbone with a view to validating the proof of concept, and carrying out measurements to determine the effectiveness of Wavelength Division Multiplexing for avionics applications. A test bed to perform measurements of several relevant parameters for various modulation schemes and frequencies (such as VHF

  6. Volcano monitoring by short wavelength infrared satellite remote sensing

    NASA Technical Reports Server (NTRS)

    Rothery, D. A.; Francis, P. W.; Wood, C. A.

    1988-01-01

    The use of short wavelength IR Landsat TM data for volcano monitoring is examined. By determining the pixel-integrated from the TM data, it is possible to estimate the temperature and size of hot areas which occupy less than one complete pixel. Examples of volcano monitoring with remote sensing data are discussed. It is suggested that the entire volcanic temperature range (100-1200 C) could be accomplished by decreasing the band 6 gain by just one order of magnitude so that it was sensitive to radiance from 1 to 100 mW/sq cm/sr/micron.

  7. Astronomical polarization studies at radio and infrared wavelengths. Part 2: Far infrared polarization of dust clouds

    NASA Technical Reports Server (NTRS)

    Dennison, B. K.

    1976-01-01

    Far infrared polarization of dust clouds is examined. The recently observed 10 micron polarization of the Orion Nebula and the Galactic Center suggests that far infrared polarization may be found in these objects. Estimates are made of the degree of far infrared polarization that may exist in the Orion Nebula. An attempt to observe far infrared polarization from the Orion Nebula was carried out.

  8. Sub-Wavelength Silicon Photonic Devices for Optical Interconnect Networks

    NASA Astrophysics Data System (ADS)

    Dudley, Eric F.

    As our demand for information grows, so too does the demand for networks capable of handling this flood of data. Conventional on-chip electrical networks are approaching their limits in terms of latency, power consumption and data rates and will need to be replaced with new technology in the near future. Photonic networks promise great improvements over electrical networks, but several key challenges still hinder their widespread deployment. This thesis focuses on addressing the problem of encoding and routing data inside integrated optical communication networks. This is accomplished through electrically driven optical switches or modulators that are able to produce a binary optical data stream from a binary electrical input signal. The primary metrics used to evaluate the performance of these devices are spatial footprint, modulation/switching speed, operating voltage and power consumption per bit. Secondary concerns are device bandwidth, CMOS compatibility, tolerance to fabrication errors and device losses. In this thesis, we present a theoretical design for an electrically driven optical switch utilizing hybrid silicon-insulator-metal waveguides with a 30 square micrometer footprint, 57 Gbit/s switching speed, 2.6 fJ/bit power consumption and 1V operation. We also present experimental confirmation of the optical properties of hybrid silicon-insulator-metal waveguides which form the basis of this design.

  9. Widely tunable polarization maintaining photonic crystal fiber based parametric wavelength conversion.

    PubMed

    Murray, Robert T; Kelleher, Edmund J R; Popov, Sergei V; Mussot, Arnaud; Kudlinski, Alexandre; Taylor, James R

    2013-07-01

    We report a near-visible parametric wavelength converter comprising a polarization-maintaining photonic crystal fiber (PM-PCF) pumped by a highly versatile diode-seeded master-oscillator power amplifier system based around 1.06 μm. The device is broadly tunable in wavelength (0.74-0.81 μm), pulse duration (0.2-1.5 ns) and repetition rate (1-30 MHz). A maximum anti-Stokes slope conversion efficiency of 14.9% is achieved with corresponding anti-Stokes average output powers of 845 mW, at a wavelength of 0.775 μm. PMID:23842368

  10. A photonic digital-to-analog conversion based on multi-wavelength sampling

    NASA Astrophysics Data System (ADS)

    Zhang, Yuancheng; Zhang, Hongming; Peng, Yue; Yao, Minyu

    2008-11-01

    A novel digital-to-analog converter based on multi-wavelength pulse source is proposed and primarily demonstrated by experiment. The multi-wavelength pulse train which has been pretreated is separated in time domain through dispersion. The pulse of different wavelength corresponds to the input digital data. Only one electro-optical modulator is needed in the scheme. In the primary experiment, a 3-bit photonic digital-to-analog converter with a sample rate of 2.5 Gb/s is realized. The scheme is simple and compact compared with the scheme using multiple electro-optical modulators.

  11. Theoretical investigation of all-metal-based mushroom plasmonic metamaterial absorbers at infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Kimata, Masafumi

    2015-12-01

    High-performance wavelength-selective infrared (IR) sensors require small pixel structures, a low-thermal mass, and operation in the middle-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) regions for multicolor IR imaging. All-metal-based mushroom plasmonic metamaterial absorbers (MPMAs) were investigated theoretically and were designed to enhance the performance of wavelength-selective uncooled IR sensors. All components of the MPMAs are based on thin layers of metals such as Au without oxide insulators for increased absorption. The absorption properties of the MPMAs were investigated by rigorous coupled-wave analysis. Strong wavelength-selective absorption is realized over a wide range of MWIR and LWIR wavelengths by the plasmonic resonance of the micropatch and the narrow-gap resonance, without disturbance from the intrinsic absorption of oxide insulators. The absorption wavelength is defined mainly by the micropatch size and is longer than its period. The metal post width has less impact on the absorption properties and can maintain single-mode operation. Through-holes can be formed on the plate area to reduce the thermal mass. A small pixel size with reduced thermal mass and wideband single-mode operation can be realized using all-metal-based MPMAs.

  12. Ultra-low-power silicon photonics wavelength converter for phase-encoded telecommunication signals

    NASA Astrophysics Data System (ADS)

    Lacava, C.; Ettabib, M. A.; Cristiani, I.; Fedeli, J.-M.; Richardson, D. J.; Petropoulos, P.

    2016-03-01

    The development of compact, low power, silicon photonics CMOS compatible components for all-optical signal processing represents a key step towards the development of fully functional platforms for next generation all-optical communication networks. The wavelength conversion functionality at key nodes is highly desirable to achieve transparent interoperability and wavelength routing allowing efficient management of network resources operated with high speed, phase encoded signals. All optical wavelength conversion has already been demonstrated in Si-based devices, mainly utilizing the strong Kerr effect that silicon exhibits at telecommunication wavelengths. Unfortunately, Two Photon Absorption (TPA) and Free Carrier (FC) effects strongly limit their performance, even at moderate power levels, making them unsuitable for practical nonlinear applications. Amorphous silicon has recently emerged as a viable alternative to crystalline silicon (c-Si), showing both an enhanced Kerr as well as a reduced TPA coefficient at telecom wavelengths, with respect to its c-Si counterpart. Here we present an ultra-low power wavelength converter based on a passive, CMOS compatible, 1-mm long amorphous silicon waveguide operated at a maximum pump power level of only 70 mW. We demonstrate TPA-free Four Wave Mixing (FWM)-based wavelength conversion of Binary Phase Shift Keyed (BPSK) and Quadrature Phase Shift Keyed (QPSK) signals at 20 Gbit/s with <1 dB power penalty at BER = 10-5.

  13. Monolithic semiconductor chips as a source for broadband wavelength-multiplexed polarization entangled photons.

    PubMed

    Kang, Dongpeng; Anirban, Ankita; Helmy, Amr S

    2016-06-27

    Generating entangled photons from a monolithic chip is a major milestone towards real-life applications of optical quantum information processing including quantum key distribution and quantum computing. Ultrabroadband entangled photons are of particular interest to various applications such as quantum metrology and multi-party entanglement distribution. In this work, we demonstrate the direct generation of broadband wavelength-multiplexed polarization entangled photons from a semiconductor chip for the first time. Without the use of any off-chip compensation or interferometry, entangled photons with a signal-idler separation as large as 95 nm in the telecom band were observed. The highest concurrence of 0.98±0.01 achieved in this work is also the highest, to the best of our knowledge, comparing to all previously demonstrated semiconductor waveguide sources. This work paves the way for fully integrated, ultrabroadband sources of polarization entangled photons. PMID:27410667

  14. Up-conversion single-photon detector using multi-wavelength sampling techniques.

    PubMed

    Ma, Lijun; Bienfang, Joshua C; Slattery, Oliver; Tang, Xiao

    2011-03-14

    The maximum achievable data-rate of a quantum communication system can be critically limited by the efficiency and temporal resolution of the system's single-photon detectors. Frequency up-conversion technology can be used to increase detection efficiency for IR photons. In this paper we describe a scheme to improve the temporal resolution of an up-conversion single-photon detector using multi-wavelength optical-sampling techniques, allowing for increased transmission rates in single-photon communications systems. We experimentally demonstrate our approach with an up-conversion detector using two spectrally and temporally distinct pump pulses, and show that it allows for high-fidelity single-photon detection at twice the rate supported by a conventional single-pump up-conversion detector. We also discuss the limiting factors of this approach and identify important performance-limiting trade offs. PMID:21445185

  15. Recirculating photonic filter: a wavelength-selective time delay for optically controlled phased-array antenna

    NASA Astrophysics Data System (ADS)

    Yegnanarayanan, Siva; Trinh, Paul D.; Jalali, Bahram

    1996-11-01

    A wavelength-selective photonic time delay filter is proposed and demonstrated. The device consists of an optical phased-array waveguide grating in a recirculating feedback configuration. It can function as a true-time-delay generator for squint-free beam steering in optically- controlled phased-array antennas. As the photonic filter uses the optical carrier wavelength to select the desired time delay, a one-to-one map is established between the optical carrier wavelength and the desired antenna direction, thus eliminating complex switching networks required to select the appropriate delay line. The proposed device can also function as the encoder/decoder in wavelength-CDMA. The concept uses a waveguide prism in a symmetric feedback (recirculating) configuration. The modulated optical carrier is steered by the waveguide prism to the appropriate integrated delay line depending on the carrier wavelength. The signal is delayed and is fed back into the symmetric input port. The prism then focuses the delayed beam into the common output port. Thus three sequential operations are performed: (1) wavelength demultiplexing, (2) time delay, and (3) wavelength multiplexing. It is important to note that the recirculating photonic filter has no 1/N loss; all the power at a given wavelength is diffracted into the output port. Furthermore, high resolution (6 - 8 bits) can be obtained in a compact integrated device. A prototype regular recirculating photonic filter true-time delay device was realized using a 8-channel arrayed-waveguide grating demultiplexer and external (off-chip) fiber delay lines. The grating was fabricated in the silica waveguide technology with 0.8 nm channel spacing (FSR equals 6.4 nm) and operating in the 1.5 micrometers wavelength range. Light from an external cavity tunable laser was rf modulated at 10 - 40 MHz and was coupled into the arrayed waveguide grating chip and time/phase measurements were performed sing a digital oscilloscope. Feedback delay

  16. Photon Counting Detectors for the 1.0 - 2.0 Micron Wavelength Range

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.

    2004-01-01

    We describe results on the development of greater than 200 micron diameter, single-element photon-counting detectors for the 1-2 micron wavelength range. The technical goals include quantum efficiency in the range 10-70%; detector diameter greater than 200 microns; dark count rate below 100 kilo counts-per-second (cps), and maximum count rate above 10 Mcps.

  17. Laser processing of photonic and microelectronic components using multiple visible and UV wavelength source

    NASA Astrophysics Data System (ADS)

    Illy, Elizabeth K.; Rutterford, Graham; Knowles, Martyn R. H.

    2003-07-01

    Laser processing using a multiple visible and UV wavelength copper laser source is presented with particular emphasis on photonic and microelectronic applications. Visible micromachining of ceramics and diamond are discussed in addition to UV micromachining/microfabrication of germanium doped silica, sapphire and kapton.

  18. Study of a middle-wavelength infrared athermalized optical system

    NASA Astrophysics Data System (ADS)

    Gao, Hong-Yun; Xiong, Tao; Li, Sheng-Hui

    2008-09-01

    For cooled 320 × 240 detector with staring focal plane array, a novel middle infrared athermal optical system is presented. The system is composed of 5 spherical lenses. The materials of lenses are silicon and germanium. The optical parameters and modulation transfer function (MTF) are investigated. The system has the diffraction limited image quality and stable image plane from -30 °C to 70 °C. The characteristic parameters of the system are as follows: f/number of 4, cold shield efficiency of 100%, spectrum region of 3.7 4.8 μm and transmissivity of 80%. The system has the merits of simple structure, low price, and it is easy to machining.

  19. Extension of long wavelength response by modulation doping in extrinsic germanium infrared detectors

    NASA Technical Reports Server (NTRS)

    Hadek, V.; Farhoomand, J.; Beichman, C. A.; Watson, D. M.; Jack, M. D.

    1985-01-01

    A new concept for infrared detectors based on multilayer epitaxy and modulation doping has been investigated. This permits a high doping concentration and lower excitation energy in the photodetecting layer as is necessary for longer wavelength response, without incurring the detrimental effects of increased dark current and noise as would be the case with conventional detector designs. Germanium photodetectors using conventional materials and designs have a long wavelength cutoff in the infrared at 138 microns, which can only be extended through the inconvenient application of mechanical stress or magnetic fields. As a result of this approach which was arrived at from theoretical considerations and subsequently demonstrated experimentally, the long wavelength cutoff for germanium extrinsic detectors was extended beyond 200 microns, as determined by direct infrared optical measurements.

  20. 640 x 512 Pixels Long-Wavelength Infrared (LWIR) Quantum-Dot Infrared Photodetector (QDIP) Imaging Focal Plane Array

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D.; Bandara, Sumith V.; Hill, Cory J.; Ting, David Z.; Liu, John K.; Rafol, Sir B.; Blazejewski, Edward R.; Mumolo, Jason M.; Keo, Sam A.; Krishna, Sanjay; Chang, Y. -C.; Shott, Craig A.

    2007-01-01

    Epitaxially grown self-assembled. InAs-InGaAs-GaAs quantum dots (QDs) are exploited for the development of large-format long-wavelength infrared focal plane arrays (FPAs). The dot-in-a-well (DWELL) structures were experimentally shown to absorb both 45 degrees and normal incident light, therefore, a reflection grating structure was used to enhance the quantum efficiency. The devices exhibit peak responsivity out to 8.1 micrometers, with peak detectivity reaching approximately 1 X 10(exp 10) Jones at 77 K. The devices were fabricated into the first long-wavelength 640 x 512 pixel QD infrared photodetector imaging FPA, which has produced excellent infrared imagery with noise equivalent temperature difference of 40 mK at 60-K operating temperature.

  1. Long-wavelength PTSI infrared detectors and method of fabrication thereof

    NASA Technical Reports Server (NTRS)

    Lin, True-Lon (Inventor); Park, Jin S. (Inventor); Gunapala, Sarath D. (Inventor); Jones, Eric W. (Inventor); Del Castillo, Hector M. (Inventor)

    1997-01-01

    Extended cutoff wavelengths of PtSi Schottky infrared detectors in the long wavelength infrared (LWIR) regime have been demonstrated for the first time. This result was achieved by incorporating a 1-nm-thick p+ doping spike at the PtSi/Si interface. The extended cutoff wavelengths resulted from the combined effects of an increased electric field near the silicide/Si interface due to the p+ doping spike and the Schottky image force. The p+ doping spikes were grown by molecular beam epitaxy at 450 degrees Celsius using elemental boron as the dopant source, with doping concentrations ranging from 1.times.10.sup.19 to 1.times.10.sup.21 cm.sup.-3. The cutoff wavelengths were shown to increase with increasing doping concentrations of the p+ spikes.

  2. Ultra-high-speed wavelength conversion in a silicon photonic chip.

    PubMed

    Hu, Hao; Ji, Hua; Galili, Michael; Pu, Minhao; Peucheret, Christophe; Christian H Mulvad, Hans; Yvind, Kresten; Hvam, Jørn M; Jeppesen, Palle; Oxenløwe, Leif K

    2011-10-10

    We have successfully demonstrated all-optical wavelength conversion of a 640-Gbit/s line-rate return-to-zero differential phase-shift keying (RZ-DPSK) signal based on low-power four wave mixing (FWM) in a silicon photonic chip with a switching energy of only ~110 fJ/bit. The waveguide dispersion of the silicon nanowire is nano-engineered to optimize phase matching for FWM and the switching power used for the signal processing is low enough to reduce nonlinear absorption from two-photon-absorption (TPA). These results demonstrate that high-speed wavelength conversion is achievable in silicon chips with high data integrity and indicate that high-speed operation can be obtained at moderate power levels where nonlinear absorption due to TPA and free-carrier absorption (FCA) is not detrimental. This demonstration can potentially enable high-speed optical networks on a silicon photonic chip. PMID:21996996

  3. Quantum storage of entangled telecom-wavelength photons in an erbium-doped optical fibre

    NASA Astrophysics Data System (ADS)

    Saglamyurek, Erhan; Jin, Jeongwan; Verma, Varun B.; Shaw, Matthew D.; Marsili, Francesco; Nam, Sae Woo; Oblak, Daniel; Tittel, Wolfgang

    2015-02-01

    The realization of a future quantum Internet requires the processing and storage of quantum information at local nodes and interconnecting distant nodes using free-space and fibre-optic links. Quantum memories for light are key elements of such quantum networks. However, to date, neither an atomic quantum memory for non-classical states of light operating at a wavelength compatible with standard telecom fibre infrastructure, nor a fibre-based implementation of a quantum memory, has been reported. Here, we demonstrate the storage and faithful recall of the state of a 1,532 nm wavelength photon entangled with a 795 nm photon, in an ensemble of cryogenically cooled erbium ions doped into a 20-m-long silica fibre, using a photon-echo quantum memory protocol. Despite its currently limited efficiency and storage time, our broadband light-matter interface brings fibre-based quantum networks one step closer to reality.

  4. Suspended Si/air high contrast subwavelength gratings for long-wavelength infrared reflectors

    NASA Astrophysics Data System (ADS)

    Foley, Justin M.; Phillips, Jamie D.

    2013-03-01

    We report broadband reflectance in the long-wavelength infrared (LWIR, 8-12 μm) utilizing suspended-Si, high-index-contrast subwavelength gratings (HCGs). Iterative design optimization using finite element analysis software has been performed accounting for silicon's wavelength-dependent index of refraction and extinction coefficient. Grating arrays were fabricated using commercial silicon-on-insulator (SOI) substrates, photolithography and reactive ion etching; subsequent selective wet etching of SiO2 was used to provide suspended Si/air gratings. Fourier transform infrared (FTIR) spectroscopy demonstrates broadband, polarization-dependent reflectance between 8.5 and 12 μm, which agrees with the simulated response.

  5. Single frequency and wavelength stabilized near infrared laser source for water vapor DIAL remote sensing application

    NASA Astrophysics Data System (ADS)

    Chuang, Ti; Walters, Brooke; Shuman, Tim; Losee, Andrew; Schum, Tom; Puffenberger, Kent; Burnham, Ralph

    2015-02-01

    Fibertek has demonstrated a single frequency, wavelength stabilized near infrared laser transmitter for NASA airborne water vapor DIAL application. The application required a single-frequency laser transmitter operating at 935 nm near infrared (NIR) region of the water vapor absorption spectrum, capable of being wavelength seeded and locked to a reference laser source and being tuned at least 100 pm across the water absorption spectrum for DIAL on/off measurements. Fibertek is building a laser transmitter system based on the demonstrated results. The laser system will be deployed in a high altitude aircraft (ER-2 or UAV) to autonomously perform remote, long duration and high altitude water vapor measurements.

  6. Broadband mid-infrared wavelength conversion laser based on Cr2+ doped ceramic materials

    NASA Astrophysics Data System (ADS)

    Shang, Yaping; Yin, Ke; Li, Xiao; Wang, Peng; Xu, Xiaojun

    2015-10-01

    Broadband mid-infrared lasers are desirable for pretty important applications in fields of environmental protection, medical treatment, military applications, scientific, and other domains. Recently, super-continuum laser sources have achieved striking development. However, limited by the substrate materials, the output power scaling of the broadband mid-infrared fiber laser sources could not be increased drastically, especially for the long wavelength region. In this paper, we reported an experimental study about the broadband mid-infrared lasers based on Cr2+ doped II-VI ceramic materials, by using of a super-continuum laser source developed by our groups operating at 1550~2130nm with 200mW output power. The result suggested that the near-infrared spectral component of the super-continuum source was deeply absorbed by transition metal doped zinc chalcogenides ceramic materials, meanwhile the mid-infrared part, however, had been enhanced significantly by this new "power amplifier." Actually single-pass amplification efficiency was very limited. The best way to solve this problem was multi-pass amplification systems. We had shown an initial proof of this assumption by a double-pass experiments, the result was consistent with expected effect. Above all, the spectrum shaping from short wavelength to long wavelength was obtained. The innovative discovery had laid a solid foundation for high power, high efficiency, broadly tunable mid-infrared solid state lasers.

  7. Interference based square lattice photonic crystal logic gates working with different wavelengths

    NASA Astrophysics Data System (ADS)

    D'souza, Nirmala Maria; Mathew, Vincent

    2016-06-01

    We propose a new configuration of interference based OR, XOR, NOT and AND optical logic gates on a two dimensional square lattice photonic crystal (PhC) platform. The working of these devices was analyzed by the FDTD method and the operating frequency range was explored using the plane wave expansion method. The XOR and NOT gates have high contrast ratio which is more than 35 dB between high and low logic states, for a particular wavelength. All these devices are operating with multiple wavelengths. The impact of structural parameter like radius on the operating wavelength and Contrast Ratio (CR) was analyzed. It is found that the optimization of structural parameters makes it possible to obtain the operating wavelength allowed by band structure. These proposed devices were made up of linear waveguides and square ring resonator waveguides, without using nonlinear materials, optical amplifiers and external phase shifters.

  8. At what wavelengths should we search for signals from extraterrestrial intelligence? (SETI/infrared communication/interstellar communication/extraterrestrial intelligence)

    NASA Technical Reports Server (NTRS)

    Townes, C. H.

    1979-01-01

    Searches for extraterrestrial intelligence concentrate on attempts to receive signals in the microwave region, the argument being given that communication occurs there at minimum broadcasted power. Such a conclusion is shown to result only under a restricted set of assumptions. If generalized types of detection are considered, in particular photon detection rather than linear detection alone, and if advantage is taken of the directivity of telescopes at short wavelengths, then somewhat less power is required for communication at infrared wavelengths than in the microwave region. Furthermore, a variety of parameters other than power alone can be chosen for optimization by an extraterrestrial civilization.

  9. Near infrared imaging of teeth at wavelengths between 1200 and 1600 nm

    NASA Astrophysics Data System (ADS)

    Chung, Soojeong; Fried, Daniel; Staninec, Michal; Darling, Cynthia L.

    2011-03-01

    Near-IR (NIR) imaging is a new technology that is currently being investigated for the detection and assessment of dental caries without the use of ionizing radiation. Several papers have been published on the use of transillumination and reflectance NIR imaging to detect early caries in enamel. The purpose of this study was to investigate alternative near infrared wavelengths besides 1300-nm in the range from 1200- 1600-nm to determine the wavelengths that yield the highest contrast in both transmission and reflectance imaging modes. Artificial lesions were created on thirty tooth sections of varying thickness for transillumination imaging. NIR images at wavelengths from the visible to 1600-nm were also acquired for fifty-four whole teeth with occlusal lesions using a tungsten halogen lamp with several spectral filters and a Ge-enhanced CMOS image sensor. Cavity preparations were also cut into whole teeth and Z250 composite was used as a restorative material to determine the contrast between composite and enamel at NIR wavelengths. Slightly longer NIR wavelengths are likely to have better performance for the transillumination of occlusal caries lesions while 1300-nm appears best for the transillumination of proximal surfaces. Significantly higher performance was attained at wavelengths that have higher water absorption, namely 1460-nm and wavelengths greater than 1500-nm and these wavelength regions are likely to be more effective for reflectance imaging. Wavelengths with higher water absorption also provided higher contrast of composite restorations.

  10. Estimating the Infrared Radiation Wavelength Emitted by a Remote Control Device Using a Digital Camera

    ERIC Educational Resources Information Center

    Catelli, Francisco; Giovannini, Odilon; Bolzan, Vicente Dall Agnol

    2011-01-01

    The interference fringes produced by a diffraction grating illuminated with radiation from a TV remote control and a red laser beam are, simultaneously, captured by a digital camera. Based on an image with two interference patterns, an estimate of the infrared radiation wavelength emitted by a TV remote control is made. (Contains 4 figures.)

  11. Long-Wavelength Stacked Si(sub 1-x)/Si Heterojunction Internal Photoemission Infrared Detectors

    NASA Technical Reports Server (NTRS)

    Park, J. S.; Lin, T. L.; Jones, E. W.; Castillo, H. M. Del; George, T.; Gunapala, S. D.

    1993-01-01

    Utilizing the low temperature silicon molecular beam epitaxy (MBE) growth of degenerately doped SiGe layers on Si, long wavelength stacked SiGe/Si heterojunction internal photoemission (HIP) infrared detectors with multiple SiGe/Se layers have been fabricated and demonstrated.

  12. Skin hydration imaging using a long-wavelength near-infrared digital camera

    NASA Astrophysics Data System (ADS)

    Attas, E. Michael; Posthumus, Trevor B.; Schattka, Bernhard J.; Sowa, Michael G.; Mantsch, Henry H.; Zhang, Shuliang L.

    2001-07-01

    Skin hydration is a key factor in skin health. Hydration measurements can provide diagnostic information on the condition of skin and can indicate the integrity of the skin barrier function. Near-infrared spectroscopy measures the water content of living tissue by its effect on tissue reflectance at a particular wavelength. Imaging has the important advantage of showing the degree of hydration as a function of location. Short-wavelength (650-1050 nm) near infrared spectroscopic reflectance imaging has previously been used in-vivo to determine the relative water content of skin under carefully controlled laboratory conditions. We have recently developed a novel spectroscopic imaging system to acquire image sets in the long-wavelength region of the near infrared (960 to 1700 nm), where the water absorption bands are more intense. The LW-NIR systems uses a liquid- crystal tunable filter in front of the objective lens and incorporates a 12-bit digital camera with a 320-by-240-pixel indium-gallium arsenide array sensor. Custom software controls the camera and tunable filter, allowing image sets to be acquired and displayed in near-real time. Forearm skin hydration was measured in a clinical context using the long- wavelength imaging system, a short-wavelength imaging system, and non-imaging instrumentation. Among these, the LW-NIR system appears to be the most sensitive at measuring dehydration of skin.

  13. Sub-optical wavelength acoustic wave modulation of integrated photonic resonators at microwave frequencies.

    PubMed

    Tadesse, Semere Ayalew; Li, Mo

    2014-01-01

    Light-sound interactions have long been exploited in various acousto-optic devices based on bulk crystalline materials. Conventionally, these devices operate in megahertz frequency range where the acoustic wavelength is much longer than the optical wavelength and a long interaction length is required to attain significant coupling. With nanoscale transducers, acoustic waves with sub-optical wavelengths can now be excited to induce strong acousto-optic coupling in nanophotonic devices. Here we demonstrate microwave frequency surface acoustic wave transducers co-integrated with nanophotonic resonators on piezoelectric aluminum nitride substrates. Acousto-optic modulation of the resonance modes at above 10 GHz with the acoustic wavelength significantly below the optical wavelength is achieved. The phase and modal matching conditions in this scheme are investigated for efficient modulation. The new acousto-optic platform can lead to novel optical devices based on nonlinear Brillouin processes and provides a direct, wideband link between optical and microwave photons for microwave photonics and quantum optomechanics. PMID:25400144

  14. Enhancement of the short wavelength upconversion emission in inverse opal photonic crystals.

    PubMed

    Wu, Hangjun; Zhu, Jialun; Yang, Zhengwen; Yan, Dong; Wang, Rongfei; Qiu, Jianbei; Song, Zhiguo; Yu, Xue; Yang, Yong; Zhou, Dacheng; Yin, Zhaoyi

    2014-05-01

    Upconversion luminescence properties of Yb-Tb codoped Bi4Ti3O12 inverse opals have been investigated. The results show that the upconversion emission can be modulated by the photonic band gap. More significantly, in the upconversion inverse opals, the excited-state absorption of Tb3+ is greatly enhanced by the suppression of upconversion spontaneous emissions of the intermediate excited state, and thus the short wavelength upconversion emission from Tb3+ is considerably improved. We believe that the present work will be valuable for not only the foundational study of upconversion emission modifications but also new optical devices in upconversion displays and short wavelength upconversion lasers. PMID:24734648

  15. Center Wavelength Adoption Techniques for Supercontinuum Generating Highly Nonlinear Noncircular Core Photonic Crystal Fiber

    NASA Astrophysics Data System (ADS)

    Hossain, Md. Anwar; Namihira, Yoshinori

    2013-05-01

    A supercontinuum (SC) light source is designed using a highly nonlinear noncircular core photonic crystal fiber (HNL-NcPCF) with all-normal group velocity dispersion (GVD) to demonstrate how simply an SC can be generated at different center wavelengths in a normal GVD regime. Using the finite element method (FEM) with a perfectly matched layer (PML), the design of two or more PCF-based light sources at different neighboring center wavelengths is demonstrated numerically. Moreover, SC generations are demonstrated numerically at 1.06, 1.31, and 1.55 µm in a normal dispersion regime using picosecond optical pulses.

  16. Triple-wavelength infrared plasmonic thermal emitter using hybrid dielectric materials in periodic arrangement

    NASA Astrophysics Data System (ADS)

    Huang, Wei-Lun; Hsiao, Hui-Hsin; Tang, Ming-Ru; Lee, Si-Chen

    2016-08-01

    This paper presents a triple-wavelength infrared plasmonic thermal emitter using a periodic arrangement of hybrid dielectric materials within a tri-layer metal/dielectric/metal structure. The proposed arrangement makes it possible to sustain multiple resonance of localized surface plasmons (LSP), thereby providing an additional degree of freedom by which to vary the resonant wavelengths in the medium infrared region. Variations in the effective refractive index due to the different modal distribution within dielectric gratings results in multiple LSP resonances, and the resonant wavelengths can be easily tuned by altering the compositions of hybrid dielectric materials. The measured dispersion relation diagram and the finite difference time domain simulation indicated that the resonances were localized. They also indicate that the magnetic fields generated by the multiple LSP modes exhibit distribution patterns similar to that of a standing wave in the periodic arrangement of the hybrid dielectric layer, each of which presents an emission peak corresponding to a different modal order.

  17. Human infrared vision is triggered by two-photon chromophore isomerization

    PubMed Central

    Palczewska, Grazyna; Vinberg, Frans; Stremplewski, Patrycjusz; Bircher, Martin P.; Salom, David; Komar, Katarzyna; Zhang, Jianye; Cascella, Michele; Wojtkowski, Maciej; Kefalov, Vladimir J.; Palczewski, Krzysztof

    2014-01-01

    Vision relies on photoactivation of visual pigments in rod and cone photoreceptor cells of the retina. The human eye structure and the absorption spectra of pigments limit our visual perception of light. Our visual perception is most responsive to stimulating light in the 400- to 720-nm (visible) range. First, we demonstrate by psychophysical experiments that humans can perceive infrared laser emission as visible light. Moreover, we show that mammalian photoreceptors can be directly activated by near infrared light with a sensitivity that paradoxically increases at wavelengths above 900 nm, and display quadratic dependence on laser power, indicating a nonlinear optical process. Biochemical experiments with rhodopsin, cone visual pigments, and a chromophore model compound 11-cis-retinyl-propylamine Schiff base demonstrate the direct isomerization of visual chromophore by a two-photon chromophore isomerization. Indeed, quantum mechanics modeling indicates the feasibility of this mechanism. Together, these findings clearly show that human visual perception of near infrared light occurs by two-photon isomerization of visual pigments. PMID:25453064

  18. Heterogeneous doped one-dimensional photonic crystal with low emissivity in infrared atmospheric window

    NASA Astrophysics Data System (ADS)

    Miao, Lei; Shi, Jiaming; Wang, Jiachun; Zhao, Dapeng; Chen, Zongsheng; Wang, Qichao

    2016-05-01

    The characteristic matrix method in thin-film optical theory was used to calculate heterogeneous doped one-dimensional photonic crystals (1-D PCs), which were fabricated by alternate deposition of Te, ZnSe, and Si materials on a silicon wafer. The heterogeneous structure was adopted to broaden the photonic band gap, within which the low reflection valley was achieved by doping. Infrared spectrum tests showed that the average emissivities of the 1-D PC were 0.0845 and 0.281, corresponding, respectively, to the bands of 3 to 5 and 8 to 14 μm. Moreover, the emissivity was 0.45 over the 5 to 8 μm nonatmospheric window, and the reflectivity was 0.28 at the wavelength of 10.6 μm. The results indicated that the heterogeneous doped 1-D PC was able to selectively achieve low emissivities over infrared atmospheric windows and a low reflectivity for the CO2 laser, which exhibited remarkable competence in compatible infrared and laser stealth applications.

  19. Near infrared single photon avalanche detector with negative feedback and self quenching

    NASA Astrophysics Data System (ADS)

    Linga, Krishna; Yevtukhov, Yuriy; Liang, Bing

    2009-08-01

    We present the design and development of a negative feedback devices using the internal discrete amplifier approach used for the development of a single photon avalanche photodetector in the near infrared wavelength region. This new family of photodetectors with negative feedback, requiring no quenching mechanism using Internal Discrete Amplification (IDA) mechanism for the realization of very high gain and low excess noise factor in the visible and near infrared spectral regions, operates in the non-gated mode under a constant bias voltage. The demonstrated device performance far exceeds any available solid state Photodetectors in the near infrared wavelength range. The measured devices have Gain > 2×105, Excess noise factor < 1.05, Rise time < 350ps, Fall time < 500ps, Dark current < 2×106 cps at room temperature, and Operating Voltage < 60V. These devices are ideal for researchers in the field of Ladar/Lidar, free space optical communication, 3D imaging, industrial and scientific instrumentation, night vision, quantum cryptography, and other military, defence and aerospace applications.

  20. Detection range enhancement using circularly polarized light in scattering environments for infrared wavelengths.

    PubMed

    van der Laan, J D; Scrymgeour, D A; Kemme, S A; Dereniak, E L

    2015-03-20

    We find for infrared wavelengths that there are broad ranges of particle sizes and refractive indices that represent fog and rain, where circular polarization can persist to longer ranges than linear polarization. Using polarization tracking Monte Carlo simulations for varying particle size, wavelength, and refractive index, we show that, for specific scene parameters, circular polarization outperforms linear polarization in maintaining the illuminating polarization state for large optical depths. This enhancement with circular polarization can be exploited to improve range and target detection in obscurant environments that are important in many critical sensing applications. Initially, researchers employed polarization-discriminating schemes, often using linearly polarized active illumination, to further distinguish target signals from the background noise. More recently, researchers have investigated circular polarization as a means to separate signal from noise even more. Specifically, we quantify both linearly and circularly polarized active illumination and show here that circular polarization persists better than linear for radiation fog in the short-wave infrared, for advection fog in the short-wave and long-wave infrared, and large particle sizes of Sahara dust around the 4 μm wavelength. Conversely, we quantify where linear polarization persists better than circular polarization for some limited particle sizes of radiation fog in the long-wave infrared, small particle sizes of Sahara dust for wavelengths of 9-10.5 μm, and large particle sizes of Sahara dust through the 8-11 μm wavelength range in the long-wave infrared. PMID:25968509

  1. Endoscopically compatible near-infrared photon migration probe

    NASA Astrophysics Data System (ADS)

    Lubawy, Carmalyn; Ramanujam, Nirmala

    2004-09-01

    We have developed a 2.3-mm-diameter fiber-optic probe for near-infrared photon migration spectroscopy that can be inserted into the body through an endoscope or biopsy needle. This probe is specifically designed to be inserted into a core biopsy needle to facilitate optical sampling of lesions during breast needle biopsy. This probe was tested on tissue phantoms containing heterogeneities (to stimulate breast lesions) of various sizes and optical properties. Under the conditions tested, the probe can measure the absorption coefficient to within 30% for heterogeneities with radii as small as 10 mm.

  2. Massive Photons: An Infrared Regularization Scheme for Lattice QCD +QED

    NASA Astrophysics Data System (ADS)

    Endres, Michael G.; Shindler, Andrea; Tiburzi, Brian C.; Walker-Loud, André

    2016-08-01

    Standard methods for including electromagnetic interactions in lattice quantum chromodynamics calculations result in power-law finite-volume corrections to physical quantities. Removing these by extrapolation requires costly computations at multiple volumes. We introduce a photon mass to alternatively regulate the infrared, and rely on effective field theory to remove its unphysical effects. Electromagnetic modifications to the hadron spectrum are reliably estimated with a precision and cost comparable to conventional approaches that utilize multiple larger volumes. A significant overall cost advantage emerges when accounting for ensemble generation. The proposed method may benefit lattice calculations involving multiple charged hadrons, as well as quantum many-body computations with long-range Coulomb interactions.

  3. High-Operating-Temperature Barrier Infrared Detector with Tailorable Cutoff Wavelength

    NASA Technical Reports Server (NTRS)

    Ting, David Z.; Hill, Cory, J.; Soibel, Alexander; Bandara, Sumith V.; Gunapala, Sarath D.

    2011-01-01

    A mid-wavelength infrared (MWIR) barrier photodetector is capable of operating at higher temperature than the prevailing MWIR detectors based on InSb. The standard high-operating-temperature barrier infrared detector (HOT-BIRD) is made with an InAsSb infrared absorber that is lattice-matched to a GaSb substrate, and has a cutoff wavelength of approximately 4 microns. To increase the versatility and utility of the HOT-BIRD, it is implemented with IR absorber materials with customizable cutoff wavelengths. The HOT-BIRD can be built with the quaternary alloy GaInAsSb as the absorber, GaAlSbAs as the barrier, on a lattice-matching GaSb substrate. The cutoff wavelength of the GaInAsSb can be tailored by adjusting the alloy composition. To build a HOT-BIRD requires a matching pair of absorber and barrier materials with the following properties: (1) their valence band edges must be approximately the same to allow unimpeded hole flow, while their conduction band edges should have a large difference to form an electron barrier; and (2) the absorber and the barrier must be respectively lattice-matched and closely lattice-matched to the substrate to ensure high material quality and low defect density. To make a HOT-BIRD with cutoff wavelength shorter than 4 microns, a GaInAsSb quaternary alloy was used as the absorber, and a matching GaAlSbAs quaternary alloy as the barrier. By changing the alloy composition, the band gap of the quaternary alloy absorber can be continuously adjusted with cutoff wavelength ranging from 4 microns down to the short wavelength infrared (SWIR). By carefully choosing the alloy composition of the barrier, a HOT-BIRD structure can be formed. With this method, a HOT-BIRD can be made with continuously tailorable cutoff wavelengths from 4 microns down to the SWIR. The HOT-BIRD detector technology is suitable for making very-large-format MWIR/SWIR focal plane arrays that can be operated by passive cooling from low Earth orbit. High-operating temperature

  4. Measurements of wavelength-dependent double photoelectron emission from single photons in VUV-sensitive photomultiplier tubes

    NASA Astrophysics Data System (ADS)

    Faham, C. H.; Gehman, V. M.; Currie, A.; Dobi, A.; Sorensen, P.; Gaitskell, R. J.

    2015-09-01

    Measurements of double photoelectron emission (DPE) probabilities as a function of wavelength are reported for Hamamatsu R8778, R8520, and R11410 VUV-sensitive photomultiplier tubes (PMTs). In DPE, a single photon strikes the PMT photocathode and produces two photoelectrons instead of a single one. It was found that the fraction of detected photons that result in DPE emission is a function of the incident photon wavelength, and manifests itself below ~250 nm. For the xenon scintillation wavelength of 175 nm, a DPE probability of 18-24% was measured depending on the tube and measurement method. This wavelength-dependent single photon response has implications for the energy calibration and photon counting of current and future liquid xenon detectors such as LUX, LZ, XENON100/1T, Panda-X and XMASS.

  5. Wavelength-Selective One- and Two-Photon Uncaging of GABA

    PubMed Central

    2013-01-01

    We have synthesized photolabile 7-diethylamino coumarin (DEAC) derivatives of γ-aminobutyric acid (GABA). These caged neurotransmitters efficiently release GABA using linear or nonlinear excitation. We used a new DEAC-based caging chromophore that has a vinyl acrylate substituent at the 3-position that shifts the absorption maximum of DEAC to about 450 nm and thus is named “DEAC450”. DEAC450-caged GABA is photolyzed with a quantum yield of 0.39 and is highly soluble and stable in physiological buffer. We found that DEAC450-caged GABA is relatively inactive toward two-photon excitation at 720 nm, so when paired with a nitroaromatic caged glutamate that is efficiently excited at such wavelengths, we could photorelease glutamate and GABA around single spine heads on neurons in brain slices with excellent wavelength selectivity using two- and one-photon photolysis, respectively. Furthermore, we found that DEAC450-caged GABA could be effectively released using two-photon excitation at 900 nm with spatial resolution of about 3 μm. Taken together, our experiments show that the DEAC450 caging chromophore holds great promise for the development of new caged compounds that will enable wavelength-selective, two-color interrogation of neuronal signaling with excellent subcellular resolution. PMID:24304264

  6. The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII): High Angular Resolution Astronomy at Far-Infrared Wavelengths

    NASA Technical Reports Server (NTRS)

    Rinehart, Stephen A.

    2008-01-01

    Astronomical studies at infrared wavelengths have dramatically improved our understanding of the universe, and observations with Spitzer, the upcoming Herschel mission. and SOFIA will continue to provide exciting new discoveries. The comparatively low spatial resolution of these missions, however. is insufficient to resolve the physical scales on which mid- to far-infrared emission arises, resulting in source and structure ambiguities that limit our ability to answer key science questions. Interferometry enables high angular resolution at these wavelengths. We have proposed a new high altitude balloon experiment, the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII). High altitude operation makes far-infrared (30- 300micron) observations possible, and BETTII's 8-meter baseline provides unprecedented angular resolution (-0.5 arcsec) in this band. BETTII will use a double- Fourier instrument to simultaneously obtain both spatial and spectral informatioT. he spatially resolved spectroscopy provided by BETTII will address key questions about the nature of disks in young cluster stars and active galactic nuclei and the envelopes of evolved stars. BETTII will also lay the groundwork for future space interferometers.

  7. Studies on output characteristics of stable dual-wavelength ytterbium-doped photonic crystal fiber laser

    NASA Astrophysics Data System (ADS)

    Tian, Hongchun; Zhang, Sa; Hou, Zhiyun; Xia, Changming; Zhou, Guiyao; Zhang, Wei; Liu, Jiantao; Wu, Jiale; Fu, Jian

    2016-06-01

    A stable dual-wavelength ytterbium-doped photonic crystal fiber laser pumped by a 976 nm laser diode has been demonstrated at room temperature. Single-wavelength, dual-wavelength laser oscillations are observed when the fiber laser operates under different pump power by using different length of fibers. Stable dual-wavelength radiation around 1045 nm and 1075 nm has been generated simultaneously at a high pump power directly from an ytterbium-doped fiber laser without using any spectral control mechanism. A small core ytterbium-doped PCF fabricated by the powder sinter direction drawn rod technology is used as gain medium. The pump power and fiber length which can affect the output characteristics of dual-wavelength fiber laser are analyzed in the experiment. Experiments confirm that higher pump power and longer fiber length favors 1075 nm output; lower pump power and shorter fiber length favors 1045 nm output. Those results have a good reference in multi-wavelength fiber laser.

  8. Revised wavelength and spectral response calibrations for AKARI near-infrared grism spectroscopy: Cryogenic phase

    NASA Astrophysics Data System (ADS)

    Baba, Shunsuke; Nakagawa, Takao; Shirahata, Mai; Isobe, Naoki; Usui, Fumihiko; Ohyama, Youichi; Onaka, Takashi; Yano, Kenichi; Kochi, Chihiro

    2016-04-01

    We perform revised spectral calibrations for the AKARI near-infrared grism to correct quantitatively for the effect of the wavelength-dependent refractive index. The near-infrared grism covering the wavelength range of 2.5-5.0 μm, with a spectral resolving power of 120 at 3.6 μm, is found to be contaminated by second-order light at wavelengths longer than 4.9 μm, which is especially serious for red objects. First, we present the wavelength calibration considering the refractive index of the grism as a function of the wavelength for the first time. We find that the previous solution is positively shifted by up to 0.01 μm compared with the revised wavelengths at 2.5-5.0 μm. In addition, we demonstrate that second-order contamination occurs even with a perfect order-sorting filter owing to the wavelength dependence of the refractive index. Secondly, the spectral responses of the system from the first- and second-order light are simultaneously obtained from two types of standard objects with different colors. The response from the second-order light suggests leakage of the order-sorting filter below 2.5 μm. The relations between the output of the detector and the intensities of the first- and second-order light are formalized by a matrix equation that combines the two orders. The removal of the contaminating second-order light can be achieved by solving the matrix equation. The new calibration extends the available spectral coverage of the grism mode from 4.9 μm up to 5.0 μm. The revision can be used to study spectral features falling in these extended wavelengths, e.g., the carbon monoxide fundamental ro-vibrational absorption within nearby active galactic nuclei.

  9. Waveguide integrated superconducting single-photon detectors with high internal quantum efficiency at telecom wavelengths

    PubMed Central

    Kahl, Oliver; Ferrari, Simone; Kovalyuk, Vadim; Goltsman, Gregory N.; Korneev, Alexander; Pernice, Wolfram H. P.

    2015-01-01

    Superconducting nanowire single-photon detectors (SNSPDs) provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, compatibility with an integrated optical platform is a crucial requirement for applications in emerging quantum photonic technologies. Here we present SNSPDs embedded in nanophotonic integrated circuits which achieve internal quantum efficiencies close to unity at 1550 nm wavelength. This allows for the SNSPDs to be operated at bias currents far below the critical current where unwanted dark count events reach milli-Hz levels while on-chip detection efficiencies above 70% are maintained. The measured dark count rates correspond to noise-equivalent powers in the 10−19 W/Hz−1/2 range and the timing jitter is as low as 35 ps. Our detectors are fully scalable and interface directly with waveguide-based optical platforms. PMID:26061283

  10. Tunable multi-wavelength polymer laser based on a triangular-lattice photonic crystal structure

    NASA Astrophysics Data System (ADS)

    Huang, Wenbin; Pu, Donglin; Qiao, Wen; Wan, Wenqiang; Liu, Yanhua; Ye, Yan; Wu, Shaolong; Chen, Linsen

    2016-08-01

    A continuously tunable multi-wavelength polymer laser based on a triangular-lattice photonic crystal cavity is demonstrated. The triangular-lattice resonator was initially fabricated through multiple interference exposure and was then replicated into a low refractive index polymer via UV-nanoimprinting. The blend of a blue-emitting conjugated polymer and a red-emitting one was used as the gain medium. Three periods in the scalene triangular-lattice structure yield stable tri-wavelength laser emission (625.5 nm, 617.4 nm and 614.3 nm) in six different directions. A uniformly aligned liquid crystal (LC) layer was incorporated into the cavity as the top cladding layer. Upon heating, the orientation of LC molecules and thus the effective refractive index of the lasing mode changes which continuously shifts the lasing wavelength. A maximum tuning range of 12.2 nm was observed for the lasing mode at 625.5 nm. This tunable tri-wavelength polymer laser is simple constructed and cost-effective. It may find application in the fields of biosensors and photonic integrated circuits.

  11. Low work function surface layers produced by laser ablation using short-wavelength photons

    DOEpatents

    Balooch, Mehdi; Dinh, Long N.; Siekhaus, Wigbert J.

    2000-01-01

    Short-wavelength photons are used to ablate material from a low work function target onto a suitable substrate. The short-wavelength photons are at or below visible wavelength. The elemental composition of the deposit is controlled by the composition of the target and the gaseous environment in which the ablation process is performed. The process is carried out in a deposition chamber to which a short-wavelength laser is mounted and which includes a substrate holder which can be rotated, tilted, heated, or cooled. The target material is mounted onto a holder that spins the target during laser ablation. In addition, the deposition chamber is provided with a vacuum pump, an external gas supply with atomizer and radical generator, a gas generator for producing a flow of molecules on the substrate, and a substrate cleaning device, such as an ion gun. The substrate can be rotated and tilted, for example, whereby only the tip of an emitter can be coated with a low work function material.

  12. Multi-channel terahertz wavelength division demultiplexer with defects-coupled photonic crystal waveguide

    NASA Astrophysics Data System (ADS)

    Li, Shaopeng; Liu, Hongjun; Sun, Qibing; Huang, Nan

    2016-05-01

    Terahertz (THz) wavelength division demultiplexer based on a compact defects-coupled photonic crystal waveguide is proposed and demonstrated numerically. This device consists of an input waveguide that perpendicularly coupled with a series of defects cavities, each of which captures the resonance frequency from the input waveguide. Coupled-mode theory and finite element method are used to analyze the transmission properties of the structure. It is found that the transmission wavelength centered around 1 THz can be adjusted by changing the geometrical parameters of defects cavities, which equals to THz waves generated by optical methods such as difference frequency generation and optical rectification. Applications in this frequency range are urgently needed. Furthermore, the highest transmission efficiency of 0.94 can be achieved when a perfect wavelength-selective mirror is set in the output waveguide.

  13. Novel Si(1-x)Ge(x)/Si heterojunction internal photoemission long wavelength infrared detectors

    NASA Technical Reports Server (NTRS)

    Lin, T. L.; Maserjian, Joseph; Ksendzov, A.; Huberman, Mark L.; Terhune, R.; Krabach, T. N.

    1990-01-01

    There is a major need for long-wavelength-infrared (LWIR) detector arrays in the range of 8 to 16 microns which operate with close-cycle cryocoolers above 65 K. In addition, it would be very attractive to have Si-based infrared (IR) detectors that can be easily integrated with Si readout circuitry and have good pixel-to-pixel uniformity, which is critical for focal plane array (FPA) applications. Here, researchers report a novel Si(1-x)Ge(x)/Si heterojunction internal photoemission (HIP) detector approach with a tailorable long wavelength infrared cutoff wavelength, based on internal photoemission over the Si(1-x)Ge(x)/Si heterojunction. The HIP detectors were grown by molecular beam epitaxy (MBE), which allows one to optimize the device structure with precise control of doping profiles, layer thickness and composition. The feasibility of a novel Si(1-x)Ge(x)/Si HIP detector has been demonstrated with tailorable cutoff wavelength in the LWIR region. Photoresponse at wavelengths 2 to 10 microns are obtained with quantum efficiency (QE) above approx. 1 percent in these non-optimized device structures. It should be possible to significantly improve the QE of the HIP detectors by optimizing the thickness, composition, and doping concentration of the Si(1-x)Ge(x) layers and by configuring the detector for maximum absorption such as the use of a cavity structure. With optimization of the QE and by matching the barrier energy to the desired wavelength cutoff to minimize the thermionic current, researchers predict near background limited performance in the LWIR region with operating temperatures above 65K. Finally, with mature Si processing, the relatively simple device structure offers potential for low-cost producible arrays with excellent uniformity.

  14. Silvered three-dimensional polymeric photonic crystals having a large mid-infrared stop band

    NASA Astrophysics Data System (ADS)

    Kuebler, Stephen M.; Tal, Amir; Chen, Yun-Sheng

    2007-02-01

    Interest in three-dimensional (3D) metal photonic crystals (MPCs) has grown considerably given their potential applications in optics and photonics. Yet, experimental studies of such materials remain few because of the difficulties associated with fabricating 3D micron- and sub-micron-scale metallic structures. We report a route to MPCs based on metallization of 3D polymeric photonic crystals fabricated by multi-photon direct laser writing. Polymeric photonic crystals (PCs) having simple-cubic symmetry with periodicities varying from 1.6 to 3.2 microns were created using a cross-linkable acrylate pre-polymer. The resulting dielectric PCs were metallized by electroless deposition of silver. Analysis of the metallized structures in cross-section by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy shows that silver deposited conformally onto the entire micro-porous lattice. The dielectric and metallized PCs were characterized by Fourier transform infrared (FTIR) spectroscopy in the (001) direction. The polymer photonic crystals exhibit a stop band resulting in circa 60% reflectance centered at 3.2 to 6.4 microns, depending upon the lattice period, with a full-width at half-maximum (FWHM) of 500 nm. Interestingly, FTIR spectra of the metallized PCs show widened stop bands of nearly 6 microns FWHM, while the center wavelengths were red shifted and ranged from 6 to 7 microns. The appreciable broadening of the stop band due to the presence of the deposited silver is a result consistent with previously reported theoretical and experimental data for all-metallic 3D PCs. Thus, the approach described here appears suitable for fabricating 3D MPCs of many symmetries and basis sets and provides a path for integrating such structures with other micron-scale optical elements.

  15. Short-wavelength near infrared stimulation of the inner ear hair cells.

    PubMed

    Xia, Nan; Peng, Fei; Wang, Xing; Zheng, Xiao L; Wan, Xiao P; Yuan, Wei; Hou, Wen S

    2014-01-01

    To explore whether the short wavelength near infrared laser can stimulate the functional hair cells, pulsed laser with wavelength of 808-nm was used to stimulate guinea pigs cochlea. Compound action potential (CAP) and auditory brainstem responses (ABR) were recorded during the experiments. We successfully recorded photomechanical responses from normal hearing animals and demonstrated the responses were not induced by optical acoustic events. Furthermore, we studied the effect of different stimulation parameters on neural response. The results show that cochlear activation can be modulated with different optical parameters. PMID:25570531

  16. Wavelength-tuneable liquid crystal lasers from the visible to the near-infrared

    NASA Astrophysics Data System (ADS)

    Hands, P. J. W.; Dobson, C. A.; Morris, S. M.; Qasim, M. M.; Gardiner, D. J.; Wilkinson, T. D.; Coles, H. J.

    2011-10-01

    The study of band-edge lasing from dye-doped chiral nematic liquid crystals has thus far been largely restricted to visible wavelengths. In this paper, a wide range of commercially available laser dyes are examined for their suitability as infrared emitters within a chiral nematic host. Problems such as poor solubility and reduced quantum efficiencies are overcome, and successful band-edge lasing is demonstrated within the range of 735-850 nm, using the dyes LD800, HITC-P and DOTC-P. This paper also reports on progress towards widely tuneable liquid crystal lasers, capable of emission in the region 460- 850 nm. Key to this is the use of common pump source, capable of simultaneously exciting all of the dyes (both infrared and visible) that are present within the system. Towards this aim, we successfully demonstrate near-infrared lasing (800 nm) facilitated by Förster energy transfer between the visible dye DCM, and the infra-red dye LD800, enabling pump wavelengths anywhere between 420 and 532 nm to be used. These results demonstrate that small and low-cost tuneable visible to near-infrared laser sources are achievable, using a single common pump source. Such devices are envisaged to have wide-ranging applications including medical imaging (including optical coherence tomography), point-of-care optical medical diagnostics (such as flow cytometry), telecommunications, and optical signatures for security coatings.

  17. Efficient generation of twin photons at telecom wavelengths with 2.5 GHz repetition-rate-tunable comb laser

    PubMed Central

    Jin, Rui-Bo; Shimizu, Ryosuke; Morohashi, Isao; Wakui, Kentaro; Takeoka, Masahiro; Izumi, Shuro; Sakamoto, Takahide; Fujiwara, Mikio; Yamashita, Taro; Miki, Shigehito; Terai, Hirotaka; Wang, Zhen; Sasaki, Masahide

    2014-01-01

    Efficient generation and detection of indistinguishable twin photons are at the core of quantum information and communications technology (Q-ICT). These photons are conventionally generated by spontaneous parametric down conversion (SPDC), which is a probabilistic process, and hence occurs at a limited rate, which restricts wider applications of Q-ICT. To increase the rate, one had to excite SPDC by higher pump power, while it inevitably produced more unwanted multi-photon components, harmfully degrading quantum interference visibility. Here we solve this problem by using recently developed 10 GHz repetition-rate-tunable comb laser, combined with a group-velocity-matched nonlinear crystal, and superconducting nanowire single photon detectors. They operate at telecom wavelengths more efficiently with less noises than conventional schemes, those typically operate at visible and near infrared wavelengths generated by a 76 MHz Ti Sapphire laser and detected by Si detectors. We could show high interference visibilities, which are free from the pump-power induced degradation. Our laser, nonlinear crystal, and detectors constitute a powerful tool box, which will pave a way to implementing quantum photonics circuits with variety of good and low-cost telecom components, and will eventually realize scalable Q-ICT in optical infra-structures. PMID:25524646

  18. Efficient generation of twin photons at telecom wavelengths with 2.5 GHz repetition-rate-tunable comb laser

    NASA Astrophysics Data System (ADS)

    Jin, Rui-Bo; Shimizu, Ryosuke; Morohashi, Isao; Wakui, Kentaro; Takeoka, Masahiro; Izumi, Shuro; Sakamoto, Takahide; Fujiwara, Mikio; Yamashita, Taro; Miki, Shigehito; Terai, Hirotaka; Wang, Zhen; Sasaki, Masahide

    2014-12-01

    Efficient generation and detection of indistinguishable twin photons are at the core of quantum information and communications technology (Q-ICT). These photons are conventionally generated by spontaneous parametric down conversion (SPDC), which is a probabilistic process, and hence occurs at a limited rate, which restricts wider applications of Q-ICT. To increase the rate, one had to excite SPDC by higher pump power, while it inevitably produced more unwanted multi-photon components, harmfully degrading quantum interference visibility. Here we solve this problem by using recently developed 10 GHz repetition-rate-tunable comb laser, combined with a group-velocity-matched nonlinear crystal, and superconducting nanowire single photon detectors. They operate at telecom wavelengths more efficiently with less noises than conventional schemes, those typically operate at visible and near infrared wavelengths generated by a 76 MHz Ti Sapphire laser and detected by Si detectors. We could show high interference visibilities, which are free from the pump-power induced degradation. Our laser, nonlinear crystal, and detectors constitute a powerful tool box, which will pave a way to implementing quantum photonics circuits with variety of good and low-cost telecom components, and will eventually realize scalable Q-ICT in optical infra-structures.

  19. Exploration of the two-photon excitation spectrum of fluorescent dyes at wavelengths below the range of the Ti:Sapphire laser.

    PubMed

    Trägårdh, J; Robb, G; Amor, R; Amos, W B; Dempster, J; McConnell, G

    2015-09-01

    We have studied the wavelength dependence of the two-photon excitation efficiency for a number of common UV excitable fluorescent dyes; the nuclear stains DAPI, Hoechst and SYTOX Green, chitin- and cellulose-staining dye Calcofluor White and Alexa Fluor 350, in the visible and near-infrared wavelength range (540-800 nm). For several of the dyes, we observe a substantial increase in the fluorescence emission intensity for shorter excitation wavelengths than the 680 nm which is the shortest wavelength usually available for two-photon microscopy. We also find that although the rate of photo-bleaching increases at shorter wavelengths, it is still possible to acquire many images with higher fluorescence intensity. This is particularly useful for applications where the aim is to image the structure, rather than monitoring changes in emission intensity over extended periods of time. We measure the excitation spectrum when the dyes are used to stain biological specimens to get a more accurate representation of the spectrum of the dye in a cell environment as compared to solution-based measurements. PMID:25946127

  20. A passive long-wavelength infrared microscope with a highly sensitive phototransistor.

    PubMed

    Kajihara, Yusuke; Komiyama, Susumu; Nickels, Patrick; Ueda, Takeji

    2009-06-01

    A passive scanning confocal microscope in the long-wavelength infrared (LWIR) region has been developed for sensitive imaging of spontaneous LWIR radiation by utilizing an ultrahighly sensitive detector, called the charge-sensitive infrared phototransistor (CSIP). The microscope consisted of room-temperature components including a Ge objective lens and liquid helium temperature components including a confocal pinhole, Ge relay lenses, and CSIP detector. With the microscope, thermal radiation (wavelength of 14.7 microm) spontaneously emitted by the object was studied with a spatial resolution of 25 microm. Clear passive LWIR imaging pictures were obtained by scanning a sample consisting of glass, Al foil, Ag paste, and Au. Clear passive LWIR image was also obtained even when the sample surface was covered by a GaAs or Si plate. This work suggests usefulness of CSIP detectors for application of passive LWIR microscopy. PMID:19566205

  1. Transmittance of long-wavelength infrared surface plasmon by hexagonal periodic metal hole arrays

    NASA Astrophysics Data System (ADS)

    Lee, Byungwoo; Kwak, Hoe Min; Kim, Ha Sul

    2016-03-01

    For long wave length infrared transmission, a surface plasmonic device, having the periodic subwavelength metal hole array on Si substrate, was fabricated using photo-lithography and electron beam evaporation. The maximum transmitted wavelength was adjustable arbitrarily as a function of the period hole arrays. The maximum transmittance was measured 70.3% at 15.4 μm with a plasmonic device composed of a pitch of 5 μm and hole arrays of 3 μm. When the hole size became larger than a half pitch of the hole array, the transmitted infrared spectrum was split into two peaks. The surface plasmon mode of the six degenerated (1,0) Ag/Si was split from three to five modes depending on the incident beam angle. The blue and red wavelength shifts were measured at the same time.

  2. Infrared Multiple Photon Dissociation Spectroscopy Of Metal Cluster-Adducts

    NASA Astrophysics Data System (ADS)

    Cox, D. M.; Kaldor, A.; Zakin, M. R.

    1987-01-01

    Recent development of the laser vaporization technique combined with mass-selective detection has made possible new studies of the fundamental chemical and physical properties of unsupported transition metal clusters as a function of the number of constituent atoms. A variety of experimental techniques have been developed in our laboratory to measure ionization threshold energies, magnetic moments, and gas phase reactivity of clusters. However, studies have so far been unable to determine the cluster structure or the chemical state of chemisorbed species on gas phase clusters. The application of infrared multiple photon dissociation IRMPD to obtain the IR absorption properties of metal cluster-adsorbate species in a molecular beam is described here. Specifically using a high power, pulsed CO2 laser as the infrared source, the IRMPD spectrum for methanol chemisorbed on small iron clusters is measured as a function of the number of both iron atoms and methanols in the complex for different methanol isotopes. Both the feasibility and potential utility of IRMPD for characterizing metal cluster-adsorbate interactions are demonstrated. The method is generally applicable to any cluster or cluster-adsorbate system dependent only upon the availability of appropriate high power infrared sources.

  3. Recirculating photonic filter: a wavelength-selective time delay for phased-array antennas and wavelength code-division multiple access.

    PubMed

    Yegnanarayanan, S; Trinh, P D; Jalali, B

    1996-05-15

    A novel wavelength-selective photonic time-delay filter is proposed and demonstrated. The device consists of an optical phased-array waveguide grating in a recirculating feedback configuration. It can function as a true-time-delay generator for squint-free beam steering in optically controlled phased-array antennas and as an encoding-decoding filter for wavelength code-division multiple access. PMID:19876143

  4. Multi-photon ionization of atoms in intense short-wavelength radiation fields

    NASA Astrophysics Data System (ADS)

    Meyer, Michael

    2015-05-01

    The unprecedented characteristics of XUV and X-ray Free Electron Lasers (FELs) have stimulated numerous investigations focusing on the detailed understanding of fundamental photon-matter interactions in atoms and molecules. In particular, the high intensities (up to 106 W/cm2) giving rise to non-linear phenomena in the short wavelength regime. The basic phenomenology involves the production of highly charged ions via electron emission to which both sequential and direct multi-photon absorption processes contribute. The detailed investigation of the role and relative weight of these processes under different conditions (wavelength, pulse duration, intensity) is the key element for a comprehensive understanding of the ionization dynamics. Here the results of recent investigations are presented, performed at the FELs in Hamburg (FLASH) and Trieste (FERMI) on atomic systems with electronic structures of increasing complexity (Ar, Ne and Xe). Mainly, electron spectroscopy is used to obtain quantitative information about the relevance of various multi-photon ionization processes. For the case of Ar, a variety of processes including above threshold ionization (ATI) from 3p and 3s valence shells, direct 2p two-photon ionization and resonant 2p-4p two-photon excitations were observed and their role was quantitatively determined comparing the experimental ionization yields to ab-initio calculations of the cross sections for the multi-photon processes. Using Ar as a benchmark to prove the reliability of the combined experimental and theoretical approach, the more complex and intriguing case of Xe was studied. Especially, the analysis of the two-photon ATI from the Xe 4d shell reveals new insight into the character of the 4d giant resonance, which was unresolved in the linear one-photon regime. Finally, the influence of intense XUV radiation to the relaxation dynamics of the Ne 2s-3p resonance was investigated by angle-resolved electron spectroscopy, especially be observing

  5. Infrared images of Jupiter at 5-micrometer wavelength during the Voyager 1 encounter

    NASA Technical Reports Server (NTRS)

    Terrile, R. J.; Capps, R. W.; Backman, D. E.; Becklin, E. E.; Cruikshank, D. P.; Beichman, C. A.; Brown, R. H.; Westphal, J. A.

    1979-01-01

    A coordinated program to observe Jupiter at high spatial resolution in the 5-micrometer wavelength region was undertaken to support Voyager 1 imaging and infrared radiation experiment targeting. Jupiter was observed over a 5-month period from Palomar and Mauna Kea observatories. The frequency of observations allowed the selection of interesting areas for closer Voyager examination and also provided good short-term monitoring of variations in cloud morphology. Significant global changes in the 5-micrometer distribution are seen over this time period.

  6. A Multi-Wavelength Thermal Infrared and Reflectance Scene Simulation Model

    NASA Technical Reports Server (NTRS)

    Ballard, J. R., Jr.; Smith, J. A.; Smith, David E. (Technical Monitor)

    2002-01-01

    Several theoretical calculations are presented and our approach discussed for simulating overall composite scene thermal infrared exitance and canopy bidirectional reflectance of a forest canopy. Calculations are performed for selected wavelength bands of the DOE Multispectral Thermal Imagery and comparisons with atmospherically corrected MTI imagery are underway. NASA EO-1 Hyperion observations also are available and the favorable comparison of our reflective model results with these data are reported elsewhere.

  7. Transformation optics and metamaterials at infrared wavelength: engineering of permittivity and permeability

    NASA Astrophysics Data System (ADS)

    Ghasemi, Rasta; Degiron, Aloyse; Leroux, Xavier; Lupu, Anatole; de Lustrac, André

    2013-05-01

    The transformation optics was introduced by J. Pendry and U. Leonhardt in 2006 [1,2]. In this method an initial space is transformed into a new space and this transformed space can be materialized by a material, which the electromagnetic parameters can be deduced from the metric of the transformed space. In the general case the electromagnetic parameters are anisotropic tensors. At microwave frequencies these materials can be realized using classical metamaterials like SRR form J. Pendry or ELC from D. Smith [3]. At infrared wavelengths this realization is a challenge because the dimensions of the metamaterials are much smaller than the wavelength and become nanometric. Then the design of these metamaterials must be simplified and original methods must be developed to allow the realization of these metamaterials with controlled electromagnetic properties. In this paper we describe the realization of a multilayer metamaterial working at infrared wavelength, which the permittivity and the permeability can be adjusted separately. We give some examples of realized multilayer materials operating around 150THz, with a comparison between the results of full wave simulations of these materials and their characterizations using a Fourier Transform Infrared Spectrometer.

  8. Wavelength interleaver in a two-dimensional rod-type photonic crystal

    NASA Astrophysics Data System (ADS)

    Ni, Bo; Li, Hui; Qiu, Yishen; Jiang, Junzhen; Wang, Yufei; Lin, Guimin; Bai, Jibo; Hong, Hailian; Chen, Xiyao

    2008-11-01

    A theoretical model of wavelength interleaver, which is based on an asymmetric Mach-Zehnder interferometer (AMZI) constructed in a two-dimensional photonic crystal (2D PhC), is proposed and numerically demonstrated. The 2D PhC consists of a square lattice of dielectric cylindrical rods in air. The AMZI includes two mirrors and two splitters. Light propagates between them employing self-collimation effect. The two interferometer branches have different path lengths. By using the finite-difference time-domain method, the calculation results show that the transmission spectra at two AMZI output ports are in the shape of sinusoidal curves and have a uniform peak spacing in the frequency range from 0.191c/a to 0.200c/a. When the path length of the longer branch is increased and the shorter one is fixed, the peaks shift to the lower frequencies and the peak spacing decreases nonlinearly. Consequently, the transmission can be designed to meet various application demands by changing the length difference between the two branches. For the dimensions of the wavelength interleaver are about tens of central wavelengths, it may be applied in future photonic integrated circuits.

  9. Spectroscopic technique with wide range of wavelength information improves near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Eda, Hideo; Aoki, Hiromichi; Eura, Shigeru; Ebe, Kazutoshi

    2009-02-01

    Near-infrared spectroscopy (NIRS) calculates hemoglobin parameters, such as oxygenated hemoglobin (oxyHb) and deoxygenated hemoglobin (deoxyHb) using the near-infrared light around the wavelength of 800nm. This is based on the modified-Lambert-Beer's law that changes in absorbance are proportional to changes in hemoglobin parameters. Many conventional measurement methods uses only a few wavelengths, however, in this research, basic examination of NIRS measurement was approached by acquiring wide range of wavelength information. Venous occlusion test was performed by using the blood pressure cuff around the upper arm. Pressure of 100mmHg was then applied for about 3 minutes. During the venous occlusion, the spectrum of the lower arm muscles was measured every 15 seconds, within the range of 600 to 1100nm. It was found that other wavelength bands hold information correlating to this venous occlusion task. Technique of improving the performance of NIRS measurement using the Spectroscopic Method is very important for Brain science.

  10. Observation of enhanced visible and infrared emissions in photonic crystal thin-film light-emitting diodes

    SciTech Connect

    Cheung, Y. F.; Li, K. H.; Hui, R. S. Y.; Choi, H. W.

    2014-08-18

    Photonic crystals, in the form of closed-packed nano-pillar arrays patterned by nanosphere lithography, have been formed on the n-faces of InGaN thin-film vertical light-emitting diodes (LEDs). Through laser lift-off of the sapphire substrate, the thin-film LEDs conduct vertically with reduced dynamic resistances, as well as reduced thermal resistances. The photonic crystal plays a role in enhancing light extraction, not only at visible wavelengths but also at infrared wavelengths boosting heat radiation at high currents, so that heat-induced effects on internal quantum efficiencies are minimized. The observations are consistent with predictions from finite-difference time-domain simulations.

  11. Wavelength optimization using available laser diodes in spectral near-infrared optical tomography.

    PubMed

    Chen, Liang-Yu; Pan, Min-Cheng; Yan, Chung-Chen; Pan, Min-Chun

    2016-07-20

    For employing optimized wavelengths, a near-infrared (NIR) tomographic imaging system with multiwavelengths in a continuous wave (CW) enables us to provide accurate information of chromophores. In this paper, we discuss wavelength optimization with a selection from commercial laser diodes. Through theoretical analysis, the residual norm (R) and the condition number (κ) represent the uniqueness of a matrix problem and the smooth singular-value distribution of each chromophore, respectively. The optimum wavelengths take place for large R and small κ. We considered a total of 38 wavelengths of laser diodes in the range of 633-980 nm commercially available to discover optimum sets for a broad range of chromophore combinations. In the 38 wavelengths, there exists 501,942 (C538), 2,760,681 (C638), and 12,620,256 (C738) combinations of five, six, and seven wavelength sets, respectively, for accurately estimating chromophores (HbO2, HbR, H2O, and lipids), water, lipids, and the scattering prefactor A. With the numerical calculation, the top 10 wavelength sets were selected based on the principle of large R and small κ. In the study, the chromophore concentration for young and elderly women are investigated; finally, choosing the laser diodes with a wavelength of 650, 690, 705, 730, 870/880, 915, and 937 nm is recommended either for young or elderly women to construct a spectral NIR tomographic imaging system in the CW domain. Simulated data were used to validate the claims. PMID:27463930

  12. Two Fabry-Perot interferometers for high precision wavelength calibration in the near-infrared

    NASA Astrophysics Data System (ADS)

    Schäfer, Sebastian; Reiners, Ansgar

    2012-09-01

    The most frequently used standard light sources for spectroscopic high precision wavelength calibration are hollow cathode lamps. These lamps, however, do not provide homogeneous line distribution and intensities. Particularly in the infrared, the number of useful lines is severely limited and the spectrum is contaminated by lines of the filler gas. With the goal of achieving sub m/s stability in the infrared, as required for detecting earthlike extra-solar planets, we are developing two passively stabilized Fabry-Perot interferometers for the red visible (600-1050nm) and near infrared wavelength regions (900-1350nm). Each of the two interferometers can produce ~15,000 lines of nearly constant brightness. The Fabry-Perot interferometers aim at a RV calibration precision of 10cm/s and are optimized in line shape and spacing for the infrared planet hunting CARMENES spectrograph that is currently being built for the Calar Alto 3.5m telescope. Here we present the first results of our work.

  13. High gain and low excess noise near infrared single photon avalanche detector

    NASA Astrophysics Data System (ADS)

    Linga, Krishna; Yevtukhov, Yuriy; Liang, Bing

    2009-05-01

    We present the discrete amplification approach used for development of a very high gain and low excess noise factor in the near infrared wavelength region. The devices have the following performance characteristics: gain > 2X105, excess noise factor < 1.05, rise time < 350ps, fall time < 500ps and operating voltage < 60V. In the photon counting mode, the devices can be operated in the non-gated mode under a constant DC bias and do not require any external quenching circuit. These devices are ideal for researchers in the fields of deep space optical communication, spectroscopy, industrial and scientific instrumentation, Ladar/Lidar, quantum cryptography, night vision and other military, defense and aerospace applications.

  14. Germanium-on-silicon Vernier-effect photonic microcavities for the mid-infrared.

    PubMed

    Troia, Benedetto; Penades, Jordi Soler; Khokhar, Ali Z; Nedeljkovic, Milos; Alonso-Ramos, Carlos; Passaro, Vittorio M N; Mashanovich, Goran Z

    2016-02-01

    We present Vernier-effect photonic microcavities based on a germanium-on-silicon technology platform, operating around the mid-infrared wavelength of 3.8 μm. Cascaded racetrack resonators have been designed to operate in the second regime of the Vernier effect, and typical Vernier comb-like spectra have been successfully demonstrated with insertion losses of ∼5  dB, maximum extinction ratios of ∼23  dB, and loaded quality factors higher than 5000. Furthermore, an add-drop racetrack resonator designed for a Vernier device has been characterized, exhibiting average insertion losses of 1 dB, extinction ratios of up to 18 dB, and a quality factor of ∼1700. PMID:26907436

  15. Short-wavelength infrared photodetector on Si employing strain-induced growth of very tall InAs nanowire arrays

    PubMed Central

    Wook Shin, Hyun; Jun Lee, Sang; Gun Kim, Doo; Bae, Myung-Ho; Heo, Jaeyeong; Jin Choi, Kyoung; Jun Choi, Won; Choe, Jeong-woo; Cheol Shin, Jae

    2015-01-01

    One-dimensional crystal growth enables the epitaxial integration of III-V compound semiconductors onto a silicon (Si) substrate despite significant lattice mismatch. Here, we report a short-wavelength infrared (SWIR, 1.4–3 μm) photodetector that employs InAs nanowires (NWs) grown on Si. The wafer-scale epitaxial InAs NWs form on the Si substrate without a metal catalyst or pattern assistance; thus, the growth is free of metal-atom-induced contaminations, and is also cost-effective. InAs NW arrays with an average height of 50 μm provide excellent anti-reflective and light trapping properties over a wide wavelength range. The photodetector exhibits a peak detectivity of 1.9 × 108  cm·Hz1/2/W for the SWIR band at 77 K and operates at temperatures as high as 220 K. The SWIR photodetector on the Si platform demonstrated in this study is promising for future low-cost optical sensors and Si photonics. PMID:26035286

  16. Photon antibunching in single-walled carbon nanotubes at telecommunication wavelengths and room temperature

    SciTech Connect

    Endo, Takumi Ishi-Hayase, Junko; Maki, Hideyuki

    2015-03-16

    We investigated the photoluminescence of individual air-suspended single-walled carbon nanotubes (SWNTs) from 6 to 300 K. Time-resolved and antibunching measurements over the telecommunication wavelength range were performed using a superconducting single-photon detector. We detected moderate temperature independent antibunching behavior over the whole temperature range studied. To investigate the exciton dynamics, which is responsible for the antibunching behavior, we measured excitation-power and temperature dependence of the photoluminescence spectra and lifetime decay curves. These measurements suggested an exciton confinement effect that is likely caused by high-dielectric amorphous carbon surrounding the SWNTs. These results indicate that SWNTs are good candidates for light sources in quantum communication technologies operating in the telecommunication wavelength range and at room temperature.

  17. Polarization maintaining highly nonlinear photonic crystal fiber with closely lying two zero dispersion wavelengths

    NASA Astrophysics Data System (ADS)

    Hasan, Md. Rabiul; Anower, Md. Shamim; Hasan, Md. Imran

    2016-05-01

    A simple hexagonal photonic crystal fiber is proposed to simultaneously achieve ultrahigh birefringence, large nonlinear coefficient, and two zero dispersion wavelengths (ZDWs). The finite element method with circular perfectly matched layer boundary condition is used to simulate the designed structure. Simulation results show that it is possible to achieve two closely lying ZDWs of 1.08 and 1.29 μm for x-polarization with 0.88 and 1.20 μm for y-polarization modes, respectively. In addition, an ultrahigh birefringence of 3.15×10-2 and a high nonlinear coefficient of 58 W-1 km-1 are also obtained at the excitation wavelength of 1.55 μm. The proposed fiber can have important applications in supercontinuum generation, parametric amplification, four-wave mixing, and optical sensors design.

  18. A silicon photonic wavelength division multiplex system for high-speed data transmission in detector instrumentation

    NASA Astrophysics Data System (ADS)

    Skwierawski, P.; Schneider, M.; Karnick, D.; Eisenblätter, L.; Weber, M.

    2016-01-01

    We propose a new silicon photonics-based optical transmission system utilizing wavelength division multiplexing (WDM) . This technology has the possibility of reading out all raw data from a detector even without massive local data reduction. The transmitter in the detector volume consists of multiple integrated Mach-Zehnder modulators monolithically integrated with wavelength (de-)multiplexers. The first demonstrator currently under development aims for a data rate of 160 Gbit/s per fiber, scalable to 5 Tbit/s and beyond. We report on our recently developed Echelle grating WDM multiplexers with up to 45 channels on an area of 0.5 mm2 and electro-optic modulators providing a bandwidth of 18 GHz.

  19. Numerical calculation of phase-matching properties in photonic crystal fibers with three and four zero-dispersion wavelengths.

    PubMed

    Zhao, Xingtao; Liu, Xiaoxu; Wang, Shutao; Wang, Wei; Han, Ying; Liu, Zhaolun; Li, Shuguang; Hou, Lantian

    2015-10-19

    Photonic crystal fibers with three and four zero-dispersion wavelengths are presented through special design of the structural parameters, in which the closing to zero and ultra-flattened dispersion can be obtained. The unique phase-matching properties of the fibers with three and four zero-dispersion wavelengths are analyzed. Variation of the phase-matching wavelengths with the pump wavelengths, pump powers, dispersion properties, and fiber structural parameters is analyzed. The presence of three and four zero-dispersion wavelengths can realize wavelength conversion of optical soliton between two anomalous dispersion regions, generate six phase-matching sidebands through four-wave mixing and create more new photon pairs, which can be used for the study of supercontinuum generation, optical switches and quantum optics. PMID:26480448

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Integrated photonic switches for nanosecond packet-switched optical wavelength conversion

    NASA Astrophysics Data System (ADS)

    Fidaner, Onur; Demir, Hilmi Volkan; Sabnis, Vijit A.; Zheng, Jun-Fei; Harris, James S., Jr.; Miller, David A. B.

    2006-01-01

    We present a multifunctional photonic switch that monolithically integrates an InGaAsP/InP quantum well electroabsorption modulator and an InGaAs photodiode as a part of an on-chip, InP optoelectronic circuit. The optical multifunctionality of the switch offers many configurations to allow for different optical network functions on a single chip. Here we experimentally demonstrate GHz-range optical wavelength-converting switching with only ~10 mW of absorbed input optical power, electronically controlled packet switching with a reconfiguration time of <2.5 ns, and optically controlled packet switching in <300 ps.

  2. Integrated photonic switches for nanosecond packet-switched optical wavelength conversion.

    PubMed

    Fidaner, Onur; Demir, Hilmi Volkan; Sabnis, Vijit A; Zheng, Jun-Fei; Harris, James S; Miller, David A B

    2006-01-01

    We present a multifunctional photonic switch that monolithically integrates an InGaAsP/InP quantum well electroabsorption modulator and an InGaAs photodiode as a part of an on-chip, InP optoelectronic circuit. The optical multifunctionality of the switch offers many configurations to allow for different optical network functions on a single chip. Here we experimentally demonstrate GHz-range optical wavelength-converting switching with only ~10 mW of absorbed input optical power, electronically controlled packet switching with a reconfiguration time of <2.5 ns, and optically controlled packet switching in <300 ps. PMID:19503349

  3. Two-photon microscopy by wavelength-swept pulses delivered through single-mode fiber

    PubMed Central

    Kang, Jeon Woong; Kim, Pilhan; Alonzo, Carlo Amadeo; Park, Hyunsung; Yun, Seok H.

    2010-01-01

    Nonlinear microscopy through flexible fiber-optic catheters has potential in clinical diagnostic applications. Here, we demonstrate a new approach based on wavelength-swept narrowband pulses that permits simple fiber-optic delivery without need of the dispersion management and allows nonmechanical beam scanning. Using 0.86 ps pulses rapidly tuned from 789 nm to 822 nm at a sweep rate of 200 Hz, we demonstrate two-photon fluorescence and second-harmonic generation imaging through a 5-m-long standard single-mode fiber. PMID:20081961

  4. Qubit transfer between photons at telecom and visible wavelengths in a slow-light atomic medium

    SciTech Connect

    Gogyan, A.

    2010-02-15

    We propose a method that enables efficient conversion of the quantum information frequency between different regions of a spectrum of light based on recently demonstrated strong parametric coupling between two narrow-band single-photon pulses propagating in a slow-light atomic medium [N. Sisakyan and Yu. Malakyan, Phys. Rev. A, 75, 063831 (2007)]. We show that an input qubit at telecom wavelength is transformed into another at a visible domain in a lossless and shape-conserving manner while keeping the initial quantum coherence and entanglement. These transformations can be realized with a quantum efficiency close to its maximum value.

  5. Oscillation wavelength shifts of visible and infrared laser diodes in a magnetic field

    NASA Astrophysics Data System (ADS)

    Sato, Takashi; Matsumoto, Kouichi; Toujou, Shin-ya; Nakagawa, Takayuki; Nakano, Hiroyuki; Ohkawa, Masashi; Maruyama, Takeo; Shimba, Minoru

    1998-10-01

    The shift, which occurs in the oscillation wavelength of a semiconductor laser in a magnetic field, has been the subject of great interest, since the early 60's. During the course of the investigation, the observed shift was toward the short wavelength side, i.e., a blue shift, which was well accounted for, in terms of the Landau level. At present, we are studying how wavelength shift is affected, by applying, at room temperature, a relatively weak magnetic field, using recently developed visible and infrared diode lasers. By doing so, we have observed a red shift and a decrease in laser output-power, under a certain magnetic field conditions in its strength and direction. Since these two changes in wavelength and output power correspond to those observed at higher temperatures, we assumed that the orientation of the magnetic field affects current density in laser diodes. And then it alters temperatures around the active layer, which in turn influence oscillation wavelength and laser output-power. Also of note, was the fact that the red shift and the decrease in laser output-power occurred simultaneously, revealing an almost linear dependency on one another. This might possibly explain the heat, which developed as the result of applying the magnetic field. However, we recently observed an instance, in which visible MQW laser diodes did not exhibit this linear dependence. Because this phenomenon cannot be traced simply to the effects of heat, we are now examining it in terms of current-density alteration.

  6. On the conversion of infrared radiation from fission reactor-based photon engine into parallel beam

    NASA Astrophysics Data System (ADS)

    Gulevich, Andrey V.; Levchenko, Vladislav E.; Loginov, Nicolay I.; Kukharchuk, Oleg F.; Evtodiev, Denis A.; Zrodnikov, Anatoly V.

    2002-01-01

    The efficiency of infrared radiation conversion from photon engine based on fission reactor into parallel photon beam is discussed. Two different ways of doing that are considered. One of them is to use the parabolic mirror to convert of infrared radiation into parallel photon beam. The another one is based on the use of special lattice consisting of numerous light conductors. The experimental facility and some results are described. .

  7. GaAs/Al(x)Ga(1-x)As quantum well infra-red photodetectors with cutoff wavelength lambda(c) = 14.9 microns

    NASA Technical Reports Server (NTRS)

    Zussman, A.; Levine, B. F.; Hong, M.; Mannaerts, J. P.

    1991-01-01

    The longest-wavelength quantum well infrared photodetector (QWIP) ever measured is demonstrated. This QWIP has a cutoff wavelength of 14.9 microns. The results show that even longer wavelength detectors should be possible.

  8. Nanoporous TiO2-Based Distributed Bragg Reflectors for Near-Infrared Wavelength Applications.

    PubMed

    Guan, Xiang-Yu; Leem, Jung Woo; Yu, Jae Su

    2015-12-01

    We reported the fabrication and characteristics of distributed Bragg reflectors (DBRs), made of titanium dioxide (TiO2) dense/nanoporous film stacks, operating in the near-infrared wavelength region of 0.8-1.1 μm. To form the nanoporous TiO2 films with a low refractive index (low-n), the oblique angle deposition (OAD) technique was employed at a high incident vapor flux angle of 80 degrees. For the fabricated DBRs consisting of TiO2 dense/nanoporous (high-n/low-n) thin films, the high reflectance band was gradually increased and the stop bandwidth was narrowed with increasing the number of DBR pairs. Particularly, the TiO2 DBR with only 6 pairs exhibited a normalized stop bandwidth (Δλ/λ(c)) of -11.6% at a center wavelength (λ(c)) of 0.96 μm as well as high reflectance values of > 95% over a wide mid-infrared wavelength region of 0.9-1.01 μm (i.e., Δλ = 0.111 μm). Furthermore, the reflectance characteristics were investigated at incident light angles of 20-70 degrees for different polarized lights. For theoretical optical analyses, the reflectance calculations were also performed by a rigorous coupled-wave analysis method, showing a similar tendency to the experimentally measured data. PMID:26682392

  9. A bandgap-engineered HgCdTe PBπn long-wavelength infrared detector

    NASA Astrophysics Data System (ADS)

    Qiu, W. C.; Jiang, T.; Cheng, X. A.

    2015-09-01

    In this paper, the HgCdTe PBπn (π represents p-type absorption layer) long-wavelength infrared detector based on bandgap-engineering is designed and validated by the preliminary experiments. Numerical simulation was applied to calculate the current-voltage (I-V) characteristic and zero-bias resistance-area product (R0A) for PBπn detectors and traditional pn photodiodes. The results show that the performance of PBπn detector was significantly improved compared with that of conventional pn photodiodes. The design of PBπn barrier structure can essentially reduce the dark current, while significantly improving the responsivity. In addition, when reverse biased, optimized PBπn device can also suppress Auger processes in the absorption layer under the high temperature up to 215 K. The proposed HgCdTe long wavelength infrared detectors based on vertical PBπn structure pave the way for development of high performance and high operation temperature infrared sensor applications.

  10. Mid-infrared photodetectors operating over an extended wavelength range up to 90 K.

    PubMed

    Lao, Yan-Feng; Perera, A G Unil; Li, L H; Khanna, S P; Linfield, E H; Zhang, Y H; Wang, T M

    2016-01-15

    We report a wavelength threshold extension, from the designed value of 3.1 to 8.9 μm, in a p-type heterostructure photodetector. This is associated with the use of a graded barrier and barrier offset, and arises from hole-hole interactions in the detector absorber. Experiments show that using long-pass filters to tune the energies of incident photons gives rise to changes in the intensity of the response. This demonstrates an alternative approach to achieving tuning of the photodetector response without the need to adjust the characteristic energy that is determined by the band structure. PMID:26766695

  11. Experimental realization of a generalized superlens using negative refraction at infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Banyal, Ravinder; Casse, B. D. F.; Lu, W. T.; Huang, Y. J.; Selvarasah, S.; Dokmeci, M.; Perry, C. H.; Sridhar, S.

    2008-03-01

    We demonstrate experimentally using a near-field scanning optical microscope the imaging of a point source by a generalized superlens fabricated in InGaAsP/InP heterostructure at wavelengths around λ= 1.5 μm. The theory of superlens imaging with lens equation u + v = σd gives excellent explanation of wave refraction and imaging formation of our superlens with an effective lens property ɛeff= 0.43. This can be used as the basis for design optical elements made of photonic crystals.

  12. Characterization and modeling of microstructured chalcogenide fibers for efficient mid-infrared wavelength conversion.

    PubMed

    Xing, Sida; Grassani, Davide; Kharitonov, Svyatoslav; Billat, Adrien; Brès, Camille-Sophie

    2016-05-01

    We experimentally demonstrate wavelength conversion in the 2 µm region by four-wave mixing in an AsSe and a GeAsSe chalcogenide photonic crystal fibers. A maximum conversion efficiency of -25.4 dB is measured for 112 mW of coupled continuous wave pump in a 27 cm long fiber. We estimate the dispersion parameters and the nonlinear refractive indexes of the chalcogenide PCFs, establishing a good agreement with the values expected from simulations. The different fiber geometries and glass compositions are compared in terms of performance, showing that GeAsSe is a more suited candidate for nonlinear optics at 2 µm. Building from the fitted parameters we then propose a new tapered GeAsSe PCF geometry to tailor the waveguide dispersion and lower the zero dispersion wavelength (ZDW) closer to the 2 µm pump wavelength. Numerical simulations shows that the new design allows both an increased conversion efficiency and bandwidth, and the generation of idler waves further in the mid-IR regions, by tuning the pump wavelength in the vicinity of the fiber ZDW. PMID:27137588

  13. These images show thermal infrared radiation from Jupiter at different wavelengths which are diagnos

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images show thermal infrared radiation from Jupiter at different wavelengths which are diagnostic of physical phenomena The 7.85-micron image in the upper left shows stratospheric temperatures which are elevated in the region of the A fragment impact (to the left of bottom). Temperatures deeper in the atmosphere near 150-mbar are shown by the 17.2-micron image in the upper right. There is a small elevation of temperatures at this depth, indicated by the arrow, and confirmed by other measurements near this wavelength. This indicates that the influence of the impact of fragment A on the troposphere has been minimal. The two images in the bottom row show no readily apparent perturbation of the ammmonia condensate cloud field near 600 mbar, as diagnosed by 8.57-micron radiation, and deeper cloud layers which are diagnosed by 5-micron radiation.

  14. Near-infrared wavelength calibration of astrophysical spectrographs with the emission spectrum of the CN molecule

    NASA Astrophysics Data System (ADS)

    Boesch, Andreas; Reiners, Ansgar; Bernath, Peter F.; Seifahrt, Andreas

    2014-07-01

    Many astrophysical applications require precise wavelength calibration of high resolution spectra. Calibration sources for this purpose at near-infrared wavelengths are sparse. We present an experimental setup for an electrodeless microwave discharge lamp that produces molecular band emission spectra. The discharge is sustained inside a glass cell filled with a combination of different gases producing CN molecules with many spectral lines in the wavelength range between 1 μm and 2.5 μm. We investigate this lamp in terms of its usability for wavelength calibration in high resolution spectroscopy. In this conference contribution, we present the experimental setup and the characterization of the calibration source in terms of line identification, line intensities, and line density. We find approximately 20,000 lines in the spectral region of 1 - 2 μm with relative peak intensities in a range of two orders of magnitude. The results from a first endurance test show that the durability of the spectrum requires careful attention in the course of further development.

  15. An efficient technique for the reduction of wavelength noise in resonance-based integrated photonic sensors.

    PubMed

    Ghasemi, Farshid; Chamanzar, Maysamreza; Eftekhar, Ali A; Adibi, Ali

    2014-11-21

    A systematic study of the limit of detection (LOD) in resonance-based silicon photonic lab-on-chip sensors is presented. The effects of the noise, temperature fluctuations, and the fundamental thermodynamic limit of the resonator are studied. Wavelength noise is identified as the dominant source of noise, and an efficient technique for suppressing this noise is presented. A large ensemble of statistical data from the transmission measurements in a laser-scanning configuration on five silicon nitride (SiN) microrings is collected to discuss and identify the sources of noise. The experimental results show that the LOD is limited by a 3σ wavelength noise of ∼1.8 pm. We present a sub-periodic interferometric technique, relying on an inverse algorithm, to suppress this noise. Our technique reduces the wavelength noise by more than one order of magnitude to an ensemble average of 3σ = 120 fm, for a resonator quality factor (Q) of about 5 × 10(4) without any temperature stabilization or cooling. This technique is readily amenable to on-chip integration to realize highly accurate and low-cost lab-on-chip sensors. PMID:25243248

  16. Optical design of a mid-wavelength infrared InSb nanowire photodetector

    NASA Astrophysics Data System (ADS)

    Azizur-Rahman, K. M.; LaPierre, R. R.

    2016-08-01

    A periodic array of vertical InSb nanowires (nws) was designed for photodetectors in the mid-wavelength infrared (MWIR) region (λ = 3–5 μm). Simulations, using the finite element method, were implemented to optimize the nw array geometrical parameters (diameter (D), period (P), and length (L)) for high optical absorptance, which exceeded that of a thin film of equal thickness. Our results showed HE1n resonances in InSb nw arrays can be tuned by adjusting D and P, thus enabling multispectral absorption throughout the near infrared to MWIR region. Optical absorptance was investigated for a practical photodetector consisting of a vertical InSb nw array embedded in bisbenzocyclobutene (BCB) as a support layer for an ultrathin Ni contact layer. Polarization sensitivity of the photodetector is examined.

  17. Optical design of a mid-wavelength infrared InSb nanowire photodetector.

    PubMed

    Azizur-Rahman, K M; LaPierre, R R

    2016-08-01

    A periodic array of vertical InSb nanowires (nws) was designed for photodetectors in the mid-wavelength infrared (MWIR) region (λ = 3-5 μm). Simulations, using the finite element method, were implemented to optimize the nw array geometrical parameters (diameter (D), period (P), and length (L)) for high optical absorptance, which exceeded that of a thin film of equal thickness. Our results showed HE1n resonances in InSb nw arrays can be tuned by adjusting D and P, thus enabling multispectral absorption throughout the near infrared to MWIR region. Optical absorptance was investigated for a practical photodetector consisting of a vertical InSb nw array embedded in bisbenzocyclobutene (BCB) as a support layer for an ultrathin Ni contact layer. Polarization sensitivity of the photodetector is examined. PMID:27324593

  18. Wavelength-swept optical parametric oscillator for broadband mid-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Silva, A.; Lindsay, I. D.

    2012-06-01

    In this work we describe a wavelength-swept continuous-wave optical parametric oscillator (OPO) for the rapid acquisition of mid-infrared spectra spanning over hundreds of wavenumbers. Rapid tuning of a ytterbium-doped fibre pump laser resulted in the OPO idler tuning over 900 cm-1 in 3.36 ms at a resolution of 4.5 cm-1, within a total accessible range of 2.67 to 4.34 μm (2304-3752 cm-1). Predictable tuning characteristics allowed simple online calibration of recorded spectra for absolute mid-infrared frequency. The system thus offers a viable approach to broadband spectral acquisition in applications requiring high-radiance illumination.

  19. Emissivity measurements on historic building materials using dual-wavelength infrared thermography

    NASA Astrophysics Data System (ADS)

    Moropoulou, Antonia; Avdelidis, Nicolas P.

    2001-03-01

    The most reliable method to obtain correct emissivity values for the infrared thermographic systems and applications is to determine the emissivity of the targets to be tested. Although this approach is not possible during in situ applications, samples of the targets can be collected and measured, as in this work, in the laboratory. In the present work, the emissivity values of selected historic building materials were measured at a variety of temperatures, in the 3-5.4 micrometers and 8-12 micrometers regions of the infrared spectrum. Porous stones from the Mediterranean area and marbles, used as historic building materials, were investigated. The examined materials presented different emissivity values, caused by their surface state and microstructure. In addition, the effect of temperature and wavelength on the emissivity values of such historic building materials was also considered.

  20. Novel Infrared Phototransistors for Atmospheric CO2 Profiling at 2 Micron Wavelength

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Abedin, M. Nurul; Sulima, Oleg V.; Singh, Upendra N.; Ismail, Syed

    2004-01-01

    Two-micron detectors are critical for atmospheric carbon dioxide profiling using the lidar technique. The characterization results of a novel infrared AlGaAsSb/ InGaAsSb phototransistor are reported. Emitter dark current variation with the collector-emitter voltage at different temperatures is acquired to examine the gain mechanism. Spectral response measurements resulted in responsivity as high as 2650 A/W at 2.05 m wavelength. Bias voltage and temperature effects on the device responsivity are presented. The detectivity of this device is compared to InGaAs and HgCdTe devices.

  1. Novel Infrared Phototransistors for Atmospheric CO2 Profiling at 2 microns Wavelength

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Abedin, M. Nurul; Sulima, Oleg V.; Singh, Upendra N.; Ismail, Syed

    2004-01-01

    Two-micron detectors are critical for atmospheric carbon dioxide profiling using the lidar technique. The characterization results of a novel infrared AlGaAsSb/ InGaAsSb phototransistor are reported. Emitter dark current variation with the collector-emitter voltage at different temperatures is acquired to examine the gain mechanism. Spectral response measurements resulted in responsivity as high as 2650 A/W at 2.05 microns wavelength. Bias voltage and temperature effects on the device responsivity are presented. The detectivity of this device is compared to InGaAs and HgCdTe devices.

  2. Announcement - Scientific Importance of High Angular Resolution at Infrared and Optical Wavelengths - ESO Conference

    NASA Astrophysics Data System (ADS)

    1981-03-01

    The European Southern Observatory is organizing an international conference on the subject "SCIENTIFIC IMPORTANCE OF HIGH ANGULAR RESOLUTION AT INFRARED AND OPTICAL WAVELENGTHS", to be held in the ESO building at Garching bei München during the period of 24-27 March 1981. The purpose of this conference is to discuss, on the one hand, the systems in use or under construction and possible future developments to achieve high angular resolution and, on the other hand, to discuss the areas of astrophysics which, in the next decades, will most benefit from observations at high angular resolution.

  3. Infrared images of jupiter at 5-micrometer wavelength during the voyager 1 encounter.

    PubMed

    Terrile, R J; Capps, R W; Backman, D E; Becklin, E E; Cruikshank, D P; Beichman, C A; Brown, R H; Westphal, J A

    1979-06-01

    A coordinated program to observe Jupiter at high spatial resolution in the 5-micrometer wavelength region was undertaken to support Voyager 1 imaging and infrared radiation experiment targeting. Jupiter was observed over a 5-month period from Palomar and Mauna Kea observatories. The frequency of observations allowed the selection of interesting areas for closer Voyager examination and also provided good short-term monitoring of variations in cloud morphology. Significant global changes in the 5-micrometer distribution are seen over this time period. PMID:17800441

  4. Infrared transmission at the 3.39 micron helium-neon laser wavelength in liquid-core quartz fibers

    NASA Technical Reports Server (NTRS)

    Majumdar, A. K.; Hinkley, E. D.; Menzies, R. T.

    1979-01-01

    Infrared transmission at the 3.39 micron helium-neon laser wavelength has been measured in a tetrachloroethylene-filled fused-quartz fiber. The loss measurements were taken for three different settings of laser light intensity using a series of neutral density filters. The average value of transmission loss at this wavelength was found to be 56 dB/km.

  5. New indicator for optimal preprocessing and wavelength selection of near-infrared spectra.

    PubMed

    Skibsted, E T S; Boelens, H F M; Westerhuis, J A; Witte, D T; Smilde, A K

    2004-03-01

    Preprocessing of near-infrared spectra to remove unwanted, i.e., non-related spectral variation and selection of informative wavelengths is considered to be a crucial step prior to the construction of a quantitative calibration model. The standard methodology when comparing various preprocessing techniques and selecting different wavelengths is to compare prediction statistics computed with an independent set of data not used to make the actual calibration model. When the errors of reference value are large, no such values are available at all, or only a limited number of samples are available, other methods exist to evaluate the preprocessing method and wavelength selection. In this work we present a new indicator (SE) that only requires blank sample spectra, i.e., spectra of samples that are mixtures of the interfering constituents (everything except the analyte), a pure analyte spectrum, or alternatively, a sample spectrum where the analyte is present. The indicator is based on computing the net analyte signal of the analyte and the total error, i.e., instrumental noise and bias. By comparing the indicator values when different preprocessing techniques and wavelength selections are applied to the spectra, the optimal preprocessing technique and the optimal wavelength selection can be determined without knowledge of reference values, i.e., it minimizes the non-related spectral variation. The SE indicator is compared to two other indicators that also use net analyte signal computations. To demonstrate the feasibility of the SE indicator, two near-infrared spectral data sets from the pharmaceutical industry were used, i.e., diffuse reflectance spectra of powder samples and transmission spectra of tablets. Especially in pharmaceutical spectroscopic applications, it is expected beforehand that the non-related spectral variation is rather large and it is important to remove it. The indicator gave excellent results with respect to wavelength selection and optimal

  6. Free-space-coupled superconducting nanowire single-photon detectors for infrared optical communications.

    PubMed

    Bellei, Francesco; Cartwright, Alyssa P; McCaughan, Adam N; Dane, Andrew E; Najafi, Faraz; Zhao, Qingyuan; Berggren, Karl K

    2016-02-22

    This paper describes the construction of a cryostat and an optical system with a free-space coupling efficiency of 56.5% ± 3.4% to a superconducting nanowire single-photon detector (SNSPD) for infrared quantum communication and spectrum analysis. A 1K pot decreases the base temperature to T = 1.7 K from the 2.9 K reached by the cold head cooled by a pulse-tube cryocooler. The minimum spot size coupled to the detector chip was 6.6 ± 0.11 µm starting from a fiber source at wavelength, λ = 1.55 µm. We demonstrated photon counting on a detector with an 8 × 7.3 µm2 area. We measured a dark count rate of 95 ± 3.35 kcps and a system detection efficiency of 1.64% ± 0.13%. We explain the key steps that are required to improve further the coupling efficiency. PMID:26906988

  7. Mid-infrared gas filled photonic crystal fiber laser based on population inversion.

    PubMed

    Jones, Andrew M; Nampoothiri, A V Vasudevan; Ratanavis, Amarin; Fiedler, Tobias; Wheeler, Natalie V; Couny, François; Kadel, Rajesh; Benabid, Fetah; Washburn, Brian R; Corwin, Kristan L; Rudolph, Wolfgang

    2011-01-31

    We demonstrate for the first time an optically pumped gas laser based on population inversion using a hollow core photonic crystal fiber (HC-PCF). The HC-PCF filled with 12C2H2 gas is pumped with ~5 ns pulses at 1.52 μm and lases at 3.12 μm and 3.16 μm in the mid-infrared spectral region. The maximum measured laser pulse energy of ~6 nJ was obtained at a gas pressure of 7 torr with a fiber with 20 dB/m loss near the lasing wavelengths. While the measured slope efficiencies of this prototype did not exceed a few percent due mainly to linear losses of the fiber at the laser wavelengths, 25% slope efficiency and pulse energies of a few mJ are the predicted limits of this laser. Simulations of the laser's behavior agree qualitatively with experimental observations. PMID:21369049

  8. Bandwidth control of wavelength-selective uncooled infrared sensors using two-dimensional plasmonic absorbers

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Kimata, Masafumi

    2016-05-01

    Although standard uncooled infrared (IR) sensors can be used to record information such as the shape, position, and average radiant intensity of objects, these devices cannot capture color (that is, wavelength) data. Achieving wavelength selectivity would pave the way for the development of advanced uncooled IR sensors capable of providing color information as well as multi-color image sensors that would have significant advantages in applications such as fire detection, gas analysis, hazardous material recognition, and biological analysis. We have previously demonstrated an uncooled IR sensor incorporating a two-dimensional plasmonic absorber (2D PLA) that exhibits wavelength selectivity over a wide range in the mid- and long-IR regions. This PLA has a 2D Au-based periodic array of dimples, in which surface plasmon modes are induced and wavelength-selective absorption occurs. However, the dependence of the absorption bandwidth on certain structural parameters has yet to be clarified. The bandwidth of such devices is a vital factor when considering the practical application of these sensors to tasks such as gas detection. In the present study, control of the bandwidth was theoretically investigated using a rigorous coupled wave analysis approach. It is demonstrated that the dimple sidewall structure has a significant impact on the bandwidth and can be used to control both narrow- and broadband absorption. Increasing the sidewall slope was found to decrease the bandwidth due to suppression of cavity-mode resonance in the depth direction of the dimples. These results will contribute to the development of high-resolution, wavelength-selective uncooled IR sensors.

  9. Exploring electromagnetic response of tellurium dielectric resonator metamaterial at the infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Song, Jia-Kun; Song, Yu-Zhi; Li, Kang-Wen; Zhang, Zu-Yin; Xu, Yun; Wei, Xin; Song, Guo-Feng

    2015-10-01

    We numerically investigate the electromagnetic properties of tellurium dielectric resonator metamaterial at the infrared wavelengths. The transmission spectra, effective permittivity and permeability of the periodic tellurium metamaterial structure are investigated in detail. The linewidth of the structure in the direction of magnetic field Wx has effects on the position and strength of the electric resonance and magnetic resonance modes. With appropriately optimizing the geometric dimensions of the designed structure, the proposed tellurium metamaterial structure can provide electric resonance mode and high order magnetic resonance mode in the same frequency band. This would be helpful to analyze and design low-loss negative refraction index metamaterials at the infrared wavelengths. Project supported by the National Basic Research Program of China (Grant Nos. 2011CBA00608, 2012CB619203, 2015CB351902, and 2015CB932402), the National Key Research Program of China (Grant No. 2011ZX01015-001), and the National Natural Science Foundation of China (Grant Nos. 61036010, 61177070, 11374295, and U1431231).

  10. Mid- to long-wavelength infrared surface plasmon properties in doped zinc oxides

    NASA Astrophysics Data System (ADS)

    Cleary, Justin W.; Snure, Michael; Leedy, Kevin D.; Look, David C.; Eyink, Kurt; Tiwari, Ashutosh

    2012-09-01

    This work investigates properties of surface plasmons on doped metal oxides in the 2-20 μm wavelength regime. By varying the stoichiometry in pulse laser deposited Ga and Al doped ZnO, the plasmonic properties can be controlled via a fluctuating free carrier concentration. This deterministic approach may enable one to develop the most appropriate stoichometry of ZnAlO and ZnGaO in regards to specific plasmonic applications for particular IR wavelengths. Presented are theoretical and experimental investigations pertaining to ZnAlO and ZnGaO as surface plasmon host materials. Samples are fabricated via pulsed laser deposition and characterized by infrared ellipsometry and Hall-effect measurements. Complex permittivity spectra are presented, as well as plasmon properties such as the field propagation lengths and penetration depths, in the infrared range of interest. Drude considerations are utilized to determine how the optical properties may change with doping. Finite element simulations verify these plasmonic properties. These materials not only offer potential use as IR plasmon hosts for sensor applications, but also offer new integrated device possibilities due to stoichiometric control of electrical and optical properties.

  11. Towards efficient mid-infrared integrated photonic-lanterns

    NASA Astrophysics Data System (ADS)

    Arriola, Alexander; Choudhury, Debaditya; Thomson, Robert R.

    2015-12-01

    We report the fabrication and characterization of a prototype integrated photonic-lantern for operation in the mid-IR (λ = 3.39 μm). The device was fabricated in a commercial gallium lanthanum sulphide chalcogenide glass substrate using ultrafast laser inscription. It was formed by inscribing a two-dimensional array of single-mode waveguides, which were then brought increasingly close together to form a single multimode waveguide. We demonstrate that the lantern successfully transforms particular single-mode states into well-defined coherent multimode states, with a loss comparable to that of a straight single-mode waveguide of the same length as the lantern (∼1.6 dB). We conclude, therefore, that the device should also work equally well in the reverse direction, thus enabling the low-loss conversion of mid-IR multimode states of light into discrete single-modes. This technology may be useful in a variety of emerging areas, including free-space laser communications and mid-infrared heterodyne spectroscopy.

  12. Photonic generation of chirped microwave and millimeter wave pulses based on optical spectral shaping and wavelength-to-time mapping in silicon photonics

    NASA Astrophysics Data System (ADS)

    Chen, Lawrence R.

    2016-08-01

    We provide an overview of photonic generation of chirped microwave and millimeter wave pulses based on optical spectral shaping followed by wavelength-to-time mapping. We summarize results obtained using bulk optic/benchtop and all-fiber spectral shapers, and discuss recent developments on integrated versions in silicon photonics. In particular, we describe devices based on microring resonators and present new results obtained using integrated spectral shapers incorporating chirped Bragg gratings.

  13. Comptonization of X-rays by low-temperature electrons. [photon wavelength redistribution in cosmic sources

    NASA Technical Reports Server (NTRS)

    Illarionov, A.; Kallman, T.; Mccray, R.; Ross, R.

    1979-01-01

    A method is described for calculating the spectrum that results from the Compton scattering of a monochromatic source of X-rays by low-temperature electrons, both for initial-value relaxation problems and for steady-state spatial diffusion problems. The method gives an exact solution of the inital-value problem for evolution of the spectrum in an infinite homogeneous medium if Klein-Nishina corrections to the Thomson cross section are neglected. This, together with approximate solutions for problems in which Klein-Nishina corrections are significant and/or spatial diffusion occurs, shows spectral structure near the original photon wavelength that may be used to infer physical conditions in cosmic X-ray sources. Explicit results, shown for examples of time relaxation in an infinite medium and spatial diffusion through a uniform sphere, are compared with results obtained by Monte Carlo calculations and by solving the appropriate Fokker-Planck equation.

  14. Tunable photonic microwave generation by directly modulating a dual-wavelength amplified feedback laser

    NASA Astrophysics Data System (ADS)

    Yu, Liqiang; Lu, Dan; Sun, Yu; Zhao, Lingjuan

    2015-06-01

    A compact and simple approach to realizing tunable high-frequency photonic microwave using a directly-modulated dual-wavelength amplified feedback laser (AFL) diode is demonstrated. By directly modulating the AFL at the 1/2 sub-harmonic frequency of its fundamental mode spacing, frequency-doubled microwave is generated. At a low RF driven power of 2.8 dBm, tunable microwave outputs ranging from 15 GHz to 33 GHz are obtained with 2-GHz locking range. The phase noise and frequency stability of the generated microwave signal are also investigated. The proposed scheme requires much lower RF driven power and can be a viable choice for situations where high power and high frequency RF signal is not available.

  15. Hybrid Ytterbium-doped large-mode-area photonic crystal fiber amplifier for long wavelengths.

    PubMed

    Petersen, Sidsel R; Alkeskjold, Thomas T; Poli, Federica; Coscelli, Enrico; Jørgensen, Mette M; Laurila, Marko; Lægsgaard, Jesper; Broeng, Jes

    2012-03-12

    A large-mode-area Ytterbium-doped photonic crystal fiber amplifier with build-in gain shaping is presented. The fiber cladding consists of a hexagonal lattice of air holes, where three rows are replaced with circular high-index inclusions. Seven missing air holes define the large-mode-area core. Light confinement is achieved by combined index and bandgap guiding, which allows for single-mode operation and gain shaping through distributed spectral filtering of amplified spontaneous emission. The fiber properties are ideal for amplification in the long wavelength regime of the Ytterbium gain spectrum above 1100 nm, and red shifting of the maximum gain to 1130 nm is demonstrated. PMID:22418478

  16. Silicon nitride CMOS-compatible platform for integrated photonics applications at visible wavelengths.

    PubMed

    Romero-García, Sebastian; Merget, Florian; Zhong, Frank; Finkelstein, Hod; Witzens, Jeremy

    2013-06-17

    Silicon nitride is demonstrated as a high performance and cost-effective solution for dense integrated photonic circuits in the visible spectrum. Experimental results for nanophotonic waveguides fabricated in a standard CMOS pilot line with losses below 0.71dB/cm in an aqueous environment and 0.51dB/cm with silicon dioxide cladding are reported. Design and characterization of waveguide bends, grating couplers and multimode interference couplers (MMI) at a wavelength of 660 nm are presented. The index contrast of this technology enables high integration densities with insertion losses below 0.05 dB per 90° bend for radii as small as 35 µm. By a proper design of the buried oxide layer thickness, grating couplers with efficiencies above 38% for the TE polarization have been obtained. PMID:23787593

  17. Limiting dark current mechanisms in antimony-based superlattice infrared detectors for the long-wavelength infrared regime

    NASA Astrophysics Data System (ADS)

    Rehm, Robert; Lemke, Florian; Schmitz, Johannes; Wauro, Matthias; Walther, Martin

    2015-06-01

    A detailed understanding of limiting dark current mechanisms in InAs/GaSb type-II superlattice (T2SL) infrared detectors is key to improve the electrooptical performance of these devices. We present a six-component dark current analysis which, for the first time, takes account of sidewall-related dark current contributions in mesa-etched T2SL photodiodes. In a wide temperature range from 30K to 130K, the paper compares limiting mechanisms in two homojunction T2SL photodiode wafers for the long-wavelength infrared regime. While the two epi wafers were fabricated with nominally the same frontside process they were grown on different molecular beam epitaxy systems. In the available literature a limitation by Shockley-Read-Hall processes in the space charge region giving rise to generation-recombination (GR) dark current is the prevailing verdict on the bulk dark current mechanism in T2SL homojunction photodiodes around 77K. In contrast, we find that investigated photodiode wafers are instead limited by the diffusion mechanism and the ohmic shunt component, respectively. Furthermore, our in-depth analysis of the various dark current components has led to an interesting observation on the temperature dependence of the shunt resistance in T2SL homojunction photodiodes. Our results indicate that the GR and the shunt mechanism share the same dependence on bandgap and temperature, i.e., a proportionality to exp(-Eg/2kT).

  18. Possibility to discriminate snow types using brightness temperatures in the thermal infrared wavelength region

    NASA Astrophysics Data System (ADS)

    Hori, Masahiro; Tanikawa, Tomonori; Aoki, Teruo; Hachikubo, Akihiro; Sugiura, Konosuke; Kuchiki, Katsuyuki; Niwano, Masashi

    2013-05-01

    Spectral emissivity of snow surface in the thermal infrared (TIR) wavelength region is an important parameter for monitoring snow surface temperature in cold climate regions and also for discriminating clouds and underlying snow surfaces in polar nights using satellite observed brightness temperature data. Past in-situ observations of snow emissivity revealed that the emissivity of snow surfaces varies depending on snow type [1]. Fine dendrite snow exhibits high emissivity over 0.98 in TIR at all exiting angles (θ). As ice granules of snow surface become large, the snow emissivity in TIR decreases and exhibits a wavelength dependence due to enhanced Fresnel reflectance at a wavelength around 12μm. Reduced snow emissivity is further enhanced as exiting angle increases. For example, emissivities of coarse grain snow at wavelengths of 11μm and 12μm are 0.99 and 0.975 for the zenith direction (θ=0°) but 0.965 and 0.93 for the slant direction of θ=75°. For sun crust snow, wavelength and directional dependences of snow emissivity are further enhanced. As the extreme case, emissivity of smooth bare ice can be approximated using the Fresnel reflectance theory. This snow type dependence of TIR emissivity as a function of wavelength and exiting angle is expected to make snow type discrimination possible using TIR brightness temperatures remotely sensed from space. In this study the possibility of snow type discrimination using TIR brightness temperatures is examined. Typical channels employed for satellite TIR image sensors are at wavelengths of 11μm and 12μm. Brightness temperature differences (BTD) at these two TIR channels (11μm-12μm) are calculated using the in-situ measured emissivities. The results showed that at the zenith direction the calculated BTD ranges from 0.5K for fine snow to 1.5K for bare ice, whereas the BTD ranges from 0.5K to over 2.3K at the slant direction of θ=60°. Thus, remotely sensed BTD ranges of around 1.0K at the zenith direction

  19. Study on the long wavelength SiGe/Si heterojunction internal photoemission infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Aslan, B.; Turan, R.; Liu, H. C.

    2005-10-01

    The theory of internal photoemission in semiconductor heterojunctions has been investigated and the existing model has been extended by incorporating the effect of different effective masses in the active region and the substrate, nonspherical-nonparabolic bands, and the energy loss per collision. Photoresponse measurements on Si 1- xGe x/Si heterojunction internal photoemission (HIP) infrared photodetectors (IP) have shown that they are fit well by the theory. Qualitative model describing the mechanisms of photocurrent generation in our structures are presented. We also study the effect of a double barrier on the photoresponse spectrum of a SiGe/Si HIP IP. It has been shown that the performance of our devices depends significantly on the applied bias and the operating temperature; therefore, their cut-off wavelengths can be tuned to the desired region by changing the potential difference across the device and/or changing the device temperature. The barrier heights (correspondingly the cut-off wavelengths) of the samples have been determined from their IP spectra by using the extended model which has the wavelength and doping concentration dependent free carrier absorption parameters.

  20. A new multi-wavelength solar telescope: Optical and Near-infrared Solar Eruption Tracer (ONSET)

    NASA Astrophysics Data System (ADS)

    Fang, Cheng; Chen, Peng-Fei; Li, Zhen; Ding, Ming-De; Dai, Yu; Zhang, Xiao-Yu; Mao, Wei-Jun; Zhang, Jun-Ping; Li, Ting; Liang, Yong-Jun; Lu, Hai-Tian

    2013-12-01

    A new multi-wavelength solar telescope, the Optical and Near-infrared Solar Eruption Tracer (ONSET) of Nanjing University, has been constructed. It was fabricated at the Nanjing Institute of Astronomical Optics & Technology, and the operation is jointly administered with Yunnan Astronomical Observatory. ONSET is able to observe the Sun in three wavelength windows: He I 10830 Å, Hα and white-light at 3600 Å and 4250 Å, which are selected in order to simultaneously record the dynamics of the corona, chromosphere and photosphere respectively. Full-disk or partial-disk solar images with a field of 10' at three wavelengths can be obtained nearly simultaneously. It is designed to trace solar eruptions with high spatial and temporal resolutions. This telescope was installed at a new solar observing site near Fuxian Lake in Yunnan Province, southwest China. The site is located at E102N24, with an altitude of 1722 m. The seeing is stable and has high quality. We give a brief description of the scientific objectives and the basic structure of ONSET. Some preliminary results are also presented.

  1. Hot spot generation in energetic materials created by long-wavelength infrared radiation

    SciTech Connect

    Chen, Ming-Wei; You, Sizhu; Suslick, Kenneth S.; Dlott, Dana D.

    2014-02-10

    Hot spots produced by long-wavelength infrared (LWIR) radiation in an energetic material, crystalline RDX (1,3,5-trinitroperhydro-1,3,5-triazine), were studied by thermal-imaging microscopy. The LWIR source was a CO{sub 2} laser operating in the 28-30 THz range. Hot spot generation was studied using relatively low intensity (∼100 W cm{sup −2}), long-duration (450 ms) LWIR pulses. The hot spots could be produced repeatedly in individual RDX crystals, to investigate the fundamental mechanisms of hot spot generation by LWIR, since the peak hot-spot temperatures were kept to ∼30 K above ambient. Hot spots were generated preferentially beneath RDX crystal planes making oblique angles with the LWIR beam. Surprisingly, hot spots were more prominent when the LWIR wavelength was tuned to be weakly absorbed (absorption depth ∼30 μm) than when the LWIR wavelength was strongly absorbed (absorption depth ∼5 μm). This unexpected effect was explained using a model that accounts for LWIR refraction and RDX thermal conduction. The weakly absorbed LWIR is slightly focused underneath the oblique crystal planes, and it penetrates the RDX crystals more deeply, increasing the likelihood of irradiating RDX defect inclusions that are able to strongly absorb or internally focus the LWIR beam.

  2. Single-wavelength two-photon excitation–stimulated emission depletion (SW2PE-STED) superresolution imaging

    PubMed Central

    Bianchini, Paolo; Harke, Benjamin; Galiani, Silvia; Vicidomini, Giuseppe; Diaspro, Alberto

    2012-01-01

    We developed a new class of two-photon excitation–stimulated emission depletion (2PE-STED) optical microscope. In this work, we show the opportunity to perform superresolved fluorescence imaging, exciting and stimulating the emission of a fluorophore by means of a single wavelength. We show that a widely used red-emitting fluorophore, ATTO647N, can be two-photon excited at a wavelength allowing both 2PE and STED using the very same laser source. This fact opens the possibility to perform 2PE microscopy at four to five times STED-improved resolution, while exploiting the intrinsic advantages of nonlinear excitation. PMID:22493221

  3. At near-infrared wavelengths, following the subtraction of zodiacal light

    NASA Technical Reports Server (NTRS)

    2002-01-01

    At near-infrared wavelengths, following the subtraction of zodiacal light (see Slide 16), map pixels containing discrete bright sources are masked and the DIRBE Faint Source Model is used to subtract residual Galactic starlight in order to detect or place an upper limit on the brightness of the cosmic infrared (extragalactic) background emission (Arendt et al. 1998, ApJ, in press). Here the upper map shows the residual sky brightness at 2.2 Aum after zodiacal light subtraction and bright source masking (dark spots in maps). In this projection, the Galactic plane runs horizontally through the map. Ideally, if the zodiacal model were perfect, only the collective emissions of (faint) stars in the Milky Way and the sought-after extragalactic light (cosmic infrared background) would remain in this map. The lower map shows the DIRBE Faint Source Model. To facilitate comparison, both maps are shown on the same brightness scale and with the same pixels masked. Clearly, most of the residual 2.2 Aum emission in the upper map is attributable to stars in the Milky Way.

  4. Two-color two-photon excited fluorescence of indole: Determination of wavelength-dependent molecular parameters

    NASA Astrophysics Data System (ADS)

    Herbrich, Sebastian; Al-Hadhuri, Tawfik; Gericke, Karl-Heinz; Shternin, Peter S.; Smolin, Andrey G.; Vasyutinskii, Oleg S.

    2015-01-01

    We present a detailed study of two-color two-photon excited fluorescence in indole dissolved in propylene glycol. Femtosecond excitation pulses at effective wavelengths from 268 to 293.33 nm were used to populate the two lowest indole excited states 1La and 1Lb and polarized fluorescence was then detected. All seven molecular parameters and the two-photon polarization ratio Ω containing information on two-photon absorption dynamics, molecular lifetime τf, and rotation correlation time τrot have been determined from experiment and analyzed as a function of the excitation wavelength. The analysis of the experimental data has shown that 1Lb-1La inversion occurred under the conditions of our experiment. The two-photon absorption predominantly populated the 1La state at all excitation wavelengths but in the 287-289 nm area which contained an absorption hump of the 1Lb state 0-0 origin. The components of the two-photon excitation tensor S were analyzed giving important information on the principal tensor axes and absorption symmetry. The results obtained are in a good agreement with the results reported by other groups. The lifetime τf and the rotation correlation time τrot showed no explicit dependence on the effective excitation wavelength. Their calculated weighted average values were found to be τf = 3.83 ± 0.14 ns and τrot = 0.74 ± 0.06 ns.

  5. Numerical analysis for a solid-core photonic crystal fiber with tunable zero dispersion wavelengths

    NASA Astrophysics Data System (ADS)

    Barrientos-García, A.; Sukoivanov, Igor A.; Andrade-Lucio, J. A.; Guryev, Igor; Shulika, Oleksiy V.; Hernandez-García, J. C.; Ramos-Ortiz, G.

    2014-09-01

    Here we propose a simple design for a solid-core photonic crystal fiber made of silica by keeping the golden ratio (1.618) between pitch and air hole diameter Λ /d in a subset of six rings of air-holes with hexagonal arrangement. In the case when we have a pitch equal to one micron (Λ =1 μm), we need air-holes diameters d=0.618 μm in order to obtain the golden ratio parameter (Λ/d=1.618), and achieve two zero dispersion wavelength (ZDW) points at 725 nm and 1055 nm; this gives us the possibility to use this fiber in supercontinuum generation using a laser emission close to that points. We analyzed a series of fibers using this relation and show the possibilities of tunable ZDW in a wide range of wavelengths from 725 nm to 2000 nm with low losses and small effective area. In agreement with the ZDW point needed, the geometry of the structure can be modified to the point of having only three rings of air holes that surround the solid core with low losses and good confinement mode. The design proposed here is analyzed using the finite element method (FEM) with perfectly matched layers (PML), including the material dispersion directly into the model applying the Sellmeier's equation.

  6. Intensity modulation photonic crystal fiber based refractometer in the visible wavelength range

    NASA Astrophysics Data System (ADS)

    Liu, Yun; Chen, Shimeng; Zhang, Xinpu; Gong, Zhenfeng; Peng, Wei

    2014-11-01

    A novel evanescent field refractometer based on a two-core photonic crystal fiber (TWPCF) sandwiched between multimode fibers(MMFs) is demonstrated. Through splicing a short piece of TWPCF between two MMFs, a simple structure and high sensitivity RI sensor can be constructed. Instead of using wavelength information as sensor signal, we focus more on the light intensity signal different from most PCF based RI sensor. The TWPCF section functions as a tailorable bridge between the excited high order modes and the surrounding refractive index (SRI). With a light filter inserting in the front of white light, the transmission spectrum of the light through the sensing region occurs in a welldefined wavelength bands. As a result, the peak power of the transmission light is tailored with the SRI perturbation via the MMF-TWPCF-MMF structure. The experiment result shows a quadratic relation between the light intensity and samples within RI range of 1.33-1.41 while a linear response can be achieved from the 1.33-1.35 which is a most used RI range for biologically sensing.

  7. Reconfigurable optical interleaver modules with tunable wavelength transfer matrix function using polymer photonics lightwave circuits.

    PubMed

    Chen, Changming; Niu, Xiaoyan; Han, Chao; Shi, Zuosen; Wang, Xinbin; Sun, Xiaoqiang; Wang, Fei; Cui, Zhanchen; Zhang, Daming

    2014-08-25

    A transparent reconfigurable optical interleaver module composed of cascaded AWGs-based wavelength-channel-selector/interleaver monolithically integrated with multimode interference (MMI) variable optical attenuators (VOAs) and Mach-Zehnder interferometer (MZI) switch arrays was designed and fabricated using polymer photonic lightwave circuits. Highly fluorinated photopolymer and grafting modified organic-inorganic hybrid material were synthesized as the waveguide core and caldding, respectively. Thermo-optic (TO) tunable wavelength transfer matrix (WTM) function of the module can be achieved for optical routing network. The one-chip transmission loss is ~ 6 dB and crosstalk is less than ~25 dB for transverse-magnetic (TM) mode. The crosstalk and extinction ratio of the MMI VOAs were measured as -15.2 dB and 17.5 dB with driving current 8 mA, respectively. The modulation depth of the TO switches is obtained as ~18.2 dB with 2.2 V bias. Proposed novel interleaver module could be well suited for DWDM optical communication systems. PMID:25321200

  8. Study of silicon strip waveguides with diffraction gratings and photonic crystals tuned to a wavelength of 1.5 µm

    SciTech Connect

    Barabanenkov, M. Yu. Vyatkin, A. F.; Volkov, V. T.; Gruzintsev, A. N.; Il’in, A. I.; Trofimov, O. V.

    2015-12-15

    Single-mode submicrometer-thick strip waveguides on silicon-on-insulator substrates, fabricated by silicon-planar-technology methods are considered. To solve the problem of 1.5-µm wavelength radiation input-output and its frequency filtering, strip diffraction gratings and two-dimensional photonic crystals are integrated into waveguides. The reflection and transmission spectra of gratings and photonic crystals are calculated. The waveguide-mode-attenuation coefficient for a polycrystalline silicon waveguide is experimentally estimated.

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

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

  10. On the variation of Fourier parameters for Galactic and LMC Cepheids at optical, near-infrared and mid-infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Anupam; Kanbur, Shashi M.; Singh, Harinder P.; Macri, Lucas M.; Ngeow, Chow-Choong

    2015-03-01

    We present a light-curve analysis of fundamental-mode Galactic and Large Magellanic Cloud (LMC) Cepheids based on the Fourier decomposition technique. We have compiled light-curve data for Galactic and LMC Cepheids in optical (VI), near-infrared (JHKs) and mid-infrared (3.6 and 4.5 μm) bands from the literature and determined the variation of their Fourier parameters as a function of period and wavelength. We observed a decrease in Fourier amplitude parameters and an increase in Fourier phase parameters with increasing wavelengths at a given period. We also found a decrease in the skewness and acuteness parameters as a function of wavelength at a fixed period. We applied a binning method to analyse the progression of the mean Fourier parameters with period and wavelength. We found that for periods longer than about 20 d, the values of the Fourier amplitude parameters increase sharply for shorter wavelengths as compared to wavelengths longer than the J band. We observed the variation of the Hertzsprung progression with wavelength. The central period of the Hertzsprung progression was found to increase with wavelength in the case of the Fourier amplitude parameters and decrease with increasing wavelength in the case of phase parameters. We also observed a small variation of the central period of the progression between the Galaxy and LMC, presumably related to metallicity effects. These results will provide useful constraints for stellar pulsation codes that incorporate stellar atmosphere models to produce Cepheid light curves in various bands.

  11. Indistinguishable near-infrared single photons from an individual organic molecule

    NASA Astrophysics Data System (ADS)

    Trebbia, Jean-Baptiste; Tamarat, Philippe; Lounis, Brahim

    2010-12-01

    By using the zero-phonon line emission of an individual organic molecule, we realized a source of indistinguishable single photons in the near infrared. A Hong-Ou-Mandel interference experiment is performed and a two-photon coalescence probability higher than 50% at 2 K is obtained. The contribution of the temperature-dependent dephasing processes to the two-photon interference contrast is studied. We show that the molecule delivers nearly ideal indistinguishable single photons at the lowest temperatures when the dephasing is nearly lifetime limited. This source is used to generate postselected polarization-entangled photon pairs as a test bench for applications in quantum information.

  12. Tunable photonic microwave notch filter using SOA-based single-longitudinal mode, dual-wavelength laser.

    PubMed

    Lee, Kwanil; Lee, Ju Han; Lee, Sang Bae

    2009-07-20

    A novel photonic microwave notch filter with capability of frequency tuning is proposed and experimentally demonstrated. The scheme is based on a fiber Bragg grating (FBG)-based, single longitudinal mode, wavelength-spacing tunable dual-wavelength fiber laser and a dispersive fiber delay line. By using a symmetrical S-bending technique along the FBGs, the wavelength spacing of the laser can be tuned, which enables the microwave notch frequency tuning. Experimental results show that the notch rejection of more than 30 dB and the flexible tunability of notch frequency can be readily achieved in the range of 1.2 approximately 6.7 GHz. PMID:19654727

  13. Multi-wavelength Observations of Fast Infrared Flares from V404 Cygni in 2015

    NASA Astrophysics Data System (ADS)

    Eikenberry, Stephen S.; Dallilar, Yigit; Garner, Alan; Deno Stelter, R.; Gandhi, Poshak; Dhillon, Vik; Littlefair, Stuart; Marsh, Thomas; Fender, Rob P.; Mooley, Kunal

    2016-04-01

    We used the fast photometry mode of our new Canarias InfraRed Camera Experiment (CIRCE) on the 10.4-meter Gran Telescopio Canarias to observe V404 Cyg, a stellar mass black hole binary, on June 25, 2015 during its 2015 outburst. CIRCE provided 10Hz sampling in the Ks-band (2.2 microns) In addition, we obtained simultaneous multi wavelength data from our collaborators: three GHz radio bands from the AMI telescope and three optical/UV bands (u', g', r') from ULTRACAM on the William Herschel 4.2-meter telescope. We identify fast (1-second) IR flares with optical counterparts of varying strength/color, which we argue arise from a relativistic jet outflow. These observations provide important constraints on the emission processes and physical conditions in the jet forming region in V404 Cygni. We will discuss these results as well as their implications for relativistic jet formation around stellar-mass black holes.

  14. THE NON-UNIFORM, DYNAMIC ATMOSPHERE OF BETELGEUSE OBSERVED AT MID-INFRARED WAVELENGTHS

    SciTech Connect

    Ravi, V.; Wishnow, E. H.; Townes, C. H.; Lockwood, S.; Mistry, H.; Tatebe, K.

    2011-10-10

    We present an interferometric study of the continuum surface of the red supergiant star Betelgeuse at 11.15 {mu}m wavelength, using data obtained with the Berkeley Infrared Spatial Interferometer each year between 2006 and 2010. These data allow an investigation of an optically thick layer within 1.4 stellar radii of the photosphere. The layer has an optical depth of {approx}1 at 11.15 {mu}m, and varies in temperature between 1900 K and 2800 K and in outer radius between 1.16 and 1.36 stellar radii. Electron-hydrogen-atom collisions contribute significantly to the opacity of the layer. The layer has a non-uniform intensity distribution that changes between observing epochs. These results indicate that large-scale surface convective activity strongly influences the dynamics of the inner atmosphere of Betelgeuse and mass-loss processes.

  15. Ultraflat and low dispersion in a horizontal silicon nitride slot waveguide at near-infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Xu, Lijuan; Ni, Xiaochang; Liu, Bowen; Li, Yanfeng; Hu, Minglie

    2016-03-01

    A strip/slot hybrid horizontal silicon nitride slot waveguide is designed to provide an ultraflat and low dispersion. By optimizing the height and width of the structure, an ultraflat and low dispersion of ˜0±7 ps/nm/km over 812 nm wavelength range (from 1137 to 1949 nm) can be achieved. The waveguide with a 20-nm conformal overlayer has chromatic dispersion within ±1 ps/nm/km over 682-nm bandwidth. So the flatness is 0.0015, which is the lowest flatness in near-infrared regime of this kind of waveguide to our knowledge. The influence of the waveguide sidewall to dispersion is also discussed.

  16. Multi-wavelength Observations of Fast Infrared Flares from V404 Cygni in 2015

    NASA Astrophysics Data System (ADS)

    Dallilar, Yigit; Casella, Piergiorgio; Marsh, Tom; Gandhi, Poshak; Fender, Rob; Littlefair, Stuart; Eikenberry, Steve; Garner, Alan; Stelter, Deno; Dhillon, Vik; Mooley, Kunal

    2016-07-01

    We used the fast photometry mode of our new Canarias InfraRed Camera Experiment (CIRCE) on the 10.4-meter Gran Telescopio Canarias to observe V404 Cyg, a stellar mass black hole binary, on June 25, 2015 during its 2015 outburst. CIRCE provided 10Hz sampling in the Ks-band (2.2 microns) In addition, we obtained simultaneous multi wavelength data from our collaborators: three GHz radio bands from the AMI telescope and three optical/UV bands (u', g', r') from ULTRACAM on the William Herschel 4.2-meter telescope. We identify fast (1-second) IR flares with optical counterparts of varying strength/color, which we argue arise from a relativistic jet outflow. These observations provide important constraints on the emission processes and physical conditions in the jet forming region in V404 Cygni. We will discuss these results as well as their implications for relativistic jet formation around stellar-mass black holes.

  17. Note: Three wavelengths near-infrared spectroscopy system for compensating the light absorbance by water

    NASA Astrophysics Data System (ADS)

    Bhutta, M. Raheel; Hong, Keum-Shik; Kim, Beop-Min; Hong, Melissa Jiyoun; Kim, Yun-Hee; Lee, Se-Ho

    2014-02-01

    Given that approximately 80% of blood is water, we develop a wireless functional near-infrared spectroscopy system that detects not only the concentration changes of oxy- and deoxy-hemoglobin (HbO and HbR) during mental activity but also that of water (H2O). Additionally, it implements a water-absorption correction algorithm that improves the HbO and HbR signal strengths during an arithmetic task. The system comprises a microcontroller, an optical probe, tri-wavelength light emitting diodes, photodiodes, a WiFi communication module, and a battery. System functionality was tested by means of arithmetic-task experiments performed by healthy male subjects.

  18. Note: three wavelengths near-infrared spectroscopy system for compensating the light absorbance by water.

    PubMed

    Bhutta, M Raheel; Hong, Keum-Shik; Kim, Beop-Min; Hong, Melissa Jiyoun; Kim, Yun-Hee; Lee, Se-Ho

    2014-02-01

    Given that approximately 80% of blood is water, we develop a wireless functional near-infrared spectroscopy system that detects not only the concentration changes of oxy- and deoxy-hemoglobin (HbO and HbR) during mental activity but also that of water (H2O). Additionally, it implements a water-absorption correction algorithm that improves the HbO and HbR signal strengths during an arithmetic task. The system comprises a microcontroller, an optical probe, tri-wavelength light emitting diodes, photodiodes, a WiFi communication module, and a battery. System functionality was tested by means of arithmetic-task experiments performed by healthy male subjects. PMID:24593411

  19. Surface plasmon excitation at near-infrared wavelengths in polymer optical fibers.

    PubMed

    Hu, Xuehao; Mégret, Patrice; Caucheteur, Christophe

    2015-09-01

    We report the first excitation of surface plasmon waves at near-infrared telecommunication wavelengths using polymer optical fibers (POFs) made of poly(methyl methacrylate) (PMMA). For this, weakly tilted fiber-Bragg gratings (TFBGs) have been photo-inscribed in the core of step-index POFs and the fiber coated with a thin gold layer. Surface plasmon resonance is excited with radially polarized modes and is spectrally observed as a singular extinction of some cladding-mode resonances in the transmitted amplitude spectrum of gold-coated TFBGs. The refractometric sensitivity can reach ∼550  nm/RIU (refractive index unit) with a figure of merit of more than 2000 and intrinsic temperature self-compensation. This kind of sensor is particularly relevant to in situ operation. PMID:26368696

  20. Emitted short wavelength infrared radiation for detection and monitoring of volcanic activity

    NASA Technical Reports Server (NTRS)

    Rothery, D. A.; Francis, P. W.; Wood, C. A.

    1988-01-01

    Thematic Mapper images from LANDSAT were used to monitor volcanoes. Achievements include: (1) the discovery of a magmatic precursor to the 16 Sept. 1986 eruption of Lascar, northern Chile, on images from Mar. and July 1985 and of continuing fumarolic activity after the eruption; (2) the detection of unreported major changes in the distribution of lava lakes on Erta'Ale, Ethiopia; and (3) the mapping of a halo of still-hot spatter surrounding a vent on Mount Erebus, Antarctica, on an image acquired 5 min after a minor eruption otherwise known only from seismic records. A spaceborne short wavelength infrared sensor for observing hot phenomena of volcanoes is proposed. A polar orbit is suggested.

  1. Spectral properties of hydrogen, helium, methane, and ammonia at thermal infrared wavelengths. [for Jupiter atmosphere

    NASA Technical Reports Server (NTRS)

    Taylor, F. W.; Jones, A. D., III

    1976-01-01

    The paper presents some results of a theoretical and laboratory program to determine the thermal infrared spectral properties of the principal gaseous constituents of the atmosphere of Jupiter. Birnbaum (1975) has measured laboratory spectra in the 16- to 1000-micron wavelength range for hydrogen and hydrogen-helium mixtures at Jovian temperatures. These are compared with theoretically computed spectra in order to determine the temperature dependence of the line strengths in the pressure-induced rotational band and the overlap parameters from the translational band. Existing spectral data for methane do not agree well with measurements of the nu 4 band at room temperature. A revised allocation of line intensities is proposed. Existing data for the nu 2 (10-micron) band of ammonia agree reasonably well with measurements at room temperature and at -77 C, but there are some important discrepancies which remain to be explained.

  2. InGaAs versus HgCdTe for short-wavelength infrared applications

    NASA Astrophysics Data System (ADS)

    Rogalski, Antoni; Ciupa, Robert

    1999-04-01

    The carrier lifetimes in In(subscript x)Ga(subscript 1-x)As (InGaAs) and Hg(subscript 1-x)Cd(subscript x)Te (HgCdTe) ternary alloys for radiative and Auger recombination are calculated for temperature 300 K in the short wavelength range 1.5 less than (lambda) less than 3.7 micrometer. Due to photon recycling, an order of magnitude enhancements in the radiative lifetimes over those obtained from the standard van Roosbroeck and Shockley expression, has been assumed. This theoretical prediction has been confirmed by good agreement with experimental data for n-type In(subscript 0.53)Ga(subscript 0.47)As. The possible Auger recombination mechanisms (CHCC, CHLH and CHSH processes) in direct-gap semiconductors are investigated. In both n-type ternary alloys, the carrier lifetimes are similar, and competition between radiative and CHCC processes take place. In p-type materials the carrier lifetime are also comparable, however the most effective channels of Auger mechanisms are: CHSH process in InGaAs, and CHLH process in HgCdTe. Next, the performance of heterostructure p-on-n photovoltaic devices are considered. Theoretically predicted R(subscript o)A values are compared with experimental data reported by other authors. In(subscript 0.53)Ga(subscript 0.47)As photodiodes have shown the device performance within a factor of 10 of theoretical limit. However, the performance of InGaAs photodiodes decreases rapidly at intermediate wavelengths due to mismatch-induced defects. HgCdTe photodiodes maintain high performance close to ultimate limit over a wider range of wavelengths. In this context technology of HgCdTe is considerably advanced since the same lattice parameter of this alloy over wide composition range.

  3. The Chromospheric Solar Limb Brightening at Radio, Millimeter, Sub-millimeter, and Infrared Wavelengths

    NASA Astrophysics Data System (ADS)

    De la Luz, V.

    2016-07-01

    Observations of the emission at radio, millimeter, sub-millimeter, and infrared wavelengths in the center of the solar disk validate the autoconsistence of semi-empirical models of the chromosphere. Theoretically, these models must reproduce the emission at the solar limb. In this work, we tested both the VALC and C7 semi-empirical models by computing their emission spectrum in the frequency range from 2 GHz to 10 THz at solar limb altitudes. We calculate the Sun's theoretical radii as well as their limb brightening. Non-local thermodynamic equilibrium was computed for hydrogen, electron density, and H‑. In order to solve the radiative transfer equation, a three-dimensional (3D) geometry was employed to determine the ray paths, and Bremsstrahlung, H‑, and inverse Bremsstrahlung opacity sources were integrated in the optical depth. We compared the computed solar radii with high-resolution observations at the limb obtained by Clark. We found that there are differences between the observed and computed solar radii of 12,000 km at 20 GHz, 5000 km at 100 GHz, and 1000 km at 3 THz for both semi-empirical models. A difference of 8000 km in the solar radii was found when comparing our results against the heights obtained from Hα observations of spicules-off at the solar limb. We conclude that the solar radii cannot be reproduced by VALC and C7 semi-empirical models at radio—infrared wavelengths. Therefore, the structures in the high chromosphere provide a better measurement of the solar radii and their limb brightening as shown in previous investigations.

  4. Multi-Wavelength Near Infrared Observations of Marum and Yasur Volcanoes, Vanuatu

    NASA Astrophysics Data System (ADS)

    Howell, Robert R.; Radebaugh, Jani; Lopes, Rosaly M.; Lorenz, Ralph D.; Turtle, Elizabeth P.

    2014-11-01

    To help understand and test models of thermal emission from planetary volcanoes, we obtained in May 2014 a variety of near-infrared observations of the very active Marum lava lake on Ambrym, Vanuatu, as well as the Strombolian activity at Yasur on Tanna. Our observations include high resolution images and movies made with standard and modified cameras and camcorders. In addition, to test the planetary emission models, which typically rely on multi-wavelength observations, we developed a small inexpensive prototype imager named "Kerby", which consists of three simultaneously active near-infrared cameras operating at 0.860, 0.775, and 0.675 microns, as well as a fourth visible wavelength RGB camera. This prototype is based on the Raspberry Pi and Pi-NoIR cameras. It can record full high definition video, and is light enough to be carried by backpack and run from batteries. To date we have concentrated on the analysis of the Marum data. During our observations of the 40 m diameter lava lake, convection was so vigorous that areas of thin crust formed only intermittently and persisted for tens of seconds to a few minutes at most. The convection pattern primarily consisted of two upwelling centers located about 8 m in from the margins on opposite sides of the lake. Horizontal velocities away from the upwelling centers were approximately 4 m/s. A hot bright margin roughly 0.4 m wide frequently formed around parts of the lake perimeter. We are in the process of establishing the absolute photometry calibration to obtain temperatures, temperature distributions, and magma cooling rates.

  5. Digital lock-in detection system based on single photon counting for near-infrared functional brain imaging

    NASA Astrophysics Data System (ADS)

    Meng, Wei; Guo, Hui; Liu, Ming; Yi, Xi; Wu, Linhui; Zhao, Huijuan; Gao, Feng

    2013-03-01

    Near infrared (NIR) diffuse optical imaging (DOI) are increasingly used to detect hemodynamic changes in the cerebral cortex induced by brain activity. For the sake of capturing the dynamic changes in real-time imaging applications, such as brain imaging, digital lock-in detection technique could be applied. Using particular modulation and sampling constraints and averaging filters, one can achieve optimal noise reduction and discrimination between sources in different modulation frequencies. In this paper, we designed and developed a compact dual-wavelength continuous wave DOI system based on the single photon counting digital lock-in detection technique. According to the frequency division multiplexing light source coding technique, sine waves with different frequencies are generated so as to amplitude-modulate two laser sources with different wavelengths. The diffuse light is detected by photomultiplier tubes (PMTs) and the data is collected by the detection channels simultaneously. A digital lock-in detection circuit for photon counting measurement module and a DDS (Direct Digital Synthesizer) signal generation module were separately implemented in two FPGA development platforms. To validate the feasibility and functionality of the developed system, a series of experimental tests were performed. Preliminary results show that the system could be used to reconstruct the absorption coefficient and could separate the response of the dual wavelength sources which were modulated by sine signals of different frequencies effectively. In addition, several imaging experiments were performed on the semi-infinite solid phantom to find the "best imaging position" for a given source-detector placement.

  6. Long-wavelength PtSi infrared detectors fabricated by incorporating a p(+) doping spike grown by molecular beam epitaxy

    NASA Technical Reports Server (NTRS)

    Lin, T. L.; Park, J. S.; George, T.; Jones, E. W.; Fathauer, R. W.; Maserjian, J.

    1993-01-01

    By incorporating a 1-nm-thick p(+) doping spike at the PtSi/Si interface, we have successfully demonstrated extended cutoff wavelengths of PtSi Schottky infrared detectors in the long wavelength infrared (LWIR) regime for the first time. The extended cutoff wavelengths resulted from the combined effects of an increased electric field near the silicide/Si interface due to the p(+) doping spike and the Schottky image force. The p(+) doping spikes were grown by molecular beam epitaxy at 450 C, using elemental boron as the dopant source, with doping concentrations ranging from 5 x 10 exp 19 to 2 x 10 exp 20/cu cm. Transmission electron microscopy indicated good crystalline quality of the doping spikes. The cutoff wavelengths were shown to increase with increasing doping concentrations of the p(+) spikes. Thermionic emission dark current characteristics were observed and photoresponses in the LWIR regime were demonstrated.

  7. Short-wavelength interband cascade infrared photodetectors operating above room temperature

    DOE PAGESBeta

    Lotfi, Hossein; Li, Lu; Lei, Lin; Jiang, Yuchao; Yang, Rui Q.; Klem, John F.; Johnson, Matthew B.

    2016-01-13

    High temperature operation (250–340 K) of short-wavelength interband cascade infrared photodetectors (ICIPs) with InAs/GaSb/Al0.2In0.8Sb/GaSb superlattice absorbers has been demonstrated with a 50% cutoff wavelength of 2.9 μm at 300 K. Two ICIP structures, one with two and the other with three stages, were designed and grown to explore this multiple-stage architecture. At λ = 2.1 μm, the two- and three-stage ICIPs had Johnson-noise-limited detectivities of 5.1 × 109 and 5.8 ×109 cm Hz1/2/W, respectively, at 300 K. The better device performance of the three-stage ICIP over the two-stage ICIP confirmed the advantage of more stages for this cascade architecture. Furthermore,more » an Arrhenius activation energy of 450 meV is extracted for the bulk resistance-area product, which indicates the dominance of the diffusion current at these high temperatures.« less

  8. Determination of effective wavelengths for discrimination of fruit vinegars using near infrared spectroscopy and multivariate analysis.

    PubMed

    Liu, Fei; He, Yong; Wang, Li

    2008-05-12

    Near infrared (NIR) spectroscopy based on effective wavelengths (EWs) and chemometrics was proposed to discriminate the varieties of fruit vinegars including aloe, apple, lemon and peach vinegars. One hundred eighty samples (45 for each variety) were selected randomly for the calibration set, and 60 samples (15 for each variety) for the validation set, whereas 24 samples (6 for each variety) for the independent set. Partial least squares discriminant analysis (PLS-DA) and least squares-support vector machine (LS-SVM) were implemented for calibration models. Different input data matrices of LS-SVM were determined by latent variables (LVs) selected by explained variance, and EWs selected by x-loading weights, regression coefficients, modeling power and independent component analysis (ICA). Then the LS-SVM models were developed with a grid search technique and RBF kernel function. All LS-SVM models outperformed PLS-DA model, and the optimal LS-SVM model was achieved with EWs (4021, 4058, 4264, 4400, 4853, 5070 and 5273 cm(-1)) selected by regression coefficients. The determination coefficient (R(2)), RMSEP and total recognition ratio with cutoff value +/-0.1 in validation set were 1.000, 0.025 and 100%, respectively. The overall results indicted that the regression coefficients was an effective way for the selection of effective wavelengths. NIR spectroscopy combined with LS-SVM models had the capability to discriminate the varieties of fruit vinegars with high accuracy. PMID:18440358

  9. Quantitative evaluation of atherosclerotic plaque phantom by near-infrared multispectral imaging with three wavelengths

    NASA Astrophysics Data System (ADS)

    Nagao, Ryo; Ishii, Katsunori; Awazu, Kunio

    2014-03-01

    Atherosclerosis is a primary cause of critical ischemic disease. The risk of critical event is involved the content of lipid in unstable plaque. Near-infrared (NIR) range is effective for diagnosis of atherosclerotic plaque because of the absorption peaks of lipid. NIR multispectral imaging (NIR-MSI) is suitable for the evaluation of plaque because it can provide spectroscopic information and spatial image quickly with a simple measurement system. The purpose of this study is to evaluate the lipid concentrations in plaque phantoms quantitatively with a NIR-MSI system. A NIR-MSI system was constructed with a supercontinuum light, a grating spectrometer and a MCT camera. Plaque phantoms with different concentrations of lipid were prepared by mixing bovine fat and a biological soft tissue model to mimic the different stages of unstable plaque. We evaluated the phantoms by the NIR-MSI system with three wavelengths in the band at 1200 nm. Multispectral images were processed by spectral angle mapper method. As a result, the lipid areas of phantoms were effectively highlighted by using three wavelengths. In addition, the concentrations of lipid areas were classified according to the similarity between measured spectra and a reference spectrum. These results suggested the possibility of image enhancement and quantitative evaluation of lipid in unstable plaque with a NIR-MSI.

  10. Room temperature performance of mid-wavelength infrared InAsSb nBn detectors

    SciTech Connect

    Soibel, Alexander; Hill, Cory J.; Keo, Sam A.; Hoglund, Linda; Rosenberg, Robert; Kowalczyk, Robert; Khoshakhlagh, Arezou; Fisher, Anita; Ting, David Z.-Y.; Gunapala, Sarath D.

    2014-07-14

    In this work, we investigate the high temperature performance of mid-wavelength infrared InAsSb-AlAsSb nBn detectors with cut-off wavelengths near 4.5 μm. The quantum efficiency of these devices is 35% without antireflection coatings and does not change with temperature in the 77–325 K temperature range, indicating potential for room temperature operation. The current generation of nBn detectors shows an increase of operational bias with temperature, which is attributed to a shift in the Fermi energy level in the absorber. Analysis of the device performance shows that operational bias and quantum efficiency of these detectors can be further improved. The device dark current stays diffusion limited in the 150 K–325 K temperature range and becomes dominated by generation-recombination processes at lower temperatures. Detector detectivities are D*(λ) = 1 × 10{sup 9} (cm Hz{sup 0.5}/W) at T = 300 K and D*(λ) = 5 × 10{sup 9} (cm Hz{sup 0.5}/W) at T = 250 K, which is easily achievable with a one stage TE cooler.

  11. High operation temperature mid-wavelength interband cascade infrared photodetectors grown on InAs substrate

    NASA Astrophysics Data System (ADS)

    Zhou, Yi; Chen, Jianxin; Xu, Zhicheng; He, Li

    2016-05-01

    In recent years, interband cascade detectors (ICIP) based on typer-II superlattice have shown great performance potential at high operation temperature. In this paper, we report our studies on mid-infrared interband cascade photodetectors first grown on InAs substrate. We examined the photo-generated carriers' transport in ICIP structures by comparing three detectors grown on InAs substrate. The 2-stages ICIP device has demonstrated a high quantum efficiency around 20% at room temperature. The dark current density of the 2-stages ICIP device at -0.05V is as low as 1 nA at 80K, 1 mA at 150K, which is comparable to the state of art PIN superlattice photodetectors with similar cutoff wavelength. The Johnson-noise limited D* reaches 1.64×1014cm.Hz1/2/W at 3.65 μm and 80K, and 4.1×1010cm.Hz1/2/W at 3.8 μm and 200K. The 300 K background limited infrared performance (BLIP) operation temperature is estimated to be over 140 K.

  12. Superconducting Photonic Crystal with Nanostrips for Mid-Infrared Applications

    SciTech Connect

    Ooi, C. H. Raymond

    2011-03-30

    One dimensional photonic crystal with superconducting nanostrips and semiconductor materials can be tailored to have narrow bands, with either large transmission or large reflection. Based on the reflection and transmission coefficients, we study the temporal dynamics of the reflected and transmitted pulses from the finite photonic crystal. The output pulse dynamics show slow light effect around the narrow bands that can be useful for photonic technologies.

  13. Finely engineered slow light photonic crystal waveguides for efficient wideband wavelength-independent higher-order temporal solitons.

    PubMed

    Fu, Meicheng; Liao, Jiali; Shao, Zhengzheng; Marko, Matthew; Zhang, Yuanda; Wang, Xiaochun; Li, Xiujian

    2016-05-10

    By orthogonally dual-shifting the air-hole rows in the triangular photonic crystal waveguide, a novel finely engineered slow light silicon photonic crystal waveguide is designed for higher-order temporal solitons and ultrashort temporal pulse compression with a large fabrication tolerance. The engineering of dispersion provides the waveguide with a wide wavelength range with only low anomalous dispersion covering, which makes the compression ratio wavelength-independent and stable even under ultralow input pulse energy. The simulation results are based on nonlinear Schrödinger equation modeling, which demonstrates that the input picosecond pulses in the broad wavelength range with ultralow pJ pulse energy can be stably compressed by a factor of 6 to higher-order temporal solitons in a 250 μm short waveguide. PMID:27168285

  14. This image combines data from the DIRBE obtained at infrared wavelengths of 100, 140 and 240 Aum

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image combines data from the DIRBE obtained at infrared wavelengths of 100, 140 and 240 Aum - the longest wavelengths measured by this instrument. The sky brightness at these wavelengths is represented respectively by blue, green, and red colors in the image. This image shows where there is more material (appears brighter) and where this material is coldest (appears redder). The plane of the Milky Way Galaxy lies horizontally across the middle of the image with the Galactic center at the center. Most of the infrared radiation seen in this image originates from cold dust (approximately 20 K, or 20 degrees Centigrade above absolute zero) located in clouds of gas and dust between the stars in the Milky Way Galaxy. The wispy-looking dust features are called 'infrared cirrus.' The region of the Orion Nebula with active star formation - approximately 1,500 light years distance from the Sun - appears on the right of the image below the plane of the Milky Way. Neighboring galaxies, the Large and Small Magellanic Clouds, appear as faint 'blobs' below and slightly to the right of the Galactic center. Much of the picture appears to be the same color, indicating that there is not a large variation in the dust temperature. Because the brightness of the Solar System and Galaxy tends to decrease with increasing wavelength, these long wavelength DIRBE measurements are particularly valuable for searching for the cosmic infrared background.

  15. Long-wavelength infrared photoconductor technology based on epitaxially grown Hg1-xCdxTe

    NASA Astrophysics Data System (ADS)

    Siliquini, John F.; Fynn, Kevin A.; Musca, Charles A.; Nener, Brett D.; Dell, John M.; Faraone, Lorenzo

    1995-09-01

    The performance of Hg1-xCdxTe long wavelength infrared (LWIR) photoconductors is strongly dependent on the semiconductor surface conditions and contact characteristics. In this paper we review these effects in relation to obtaining an optimum device technology suitable for use in two-dimensional infrared focal plane arrays (IRFPAs) based on the fabrication of high performance LWIR photoconductors on epitaxially grown Hg1-xCdxTe. Although the proposed design can be applied to a variety of epitaxially grown Hg1-xCdxTe material, for optimum performance the starting Hg1-xCdxTe semiconductor consists of epitaxially grown heterostructure layers in which a two-dimensional mosaic of lateral design photoconductors are fabricated. The heterostructure layer provides high performance devices at greatly reduced power dissipation levels, while the unique design allows for the high density integration of photoconductors in a two-dimensional array geometry with high fill factor. The proposed photoconductor array with n+ blocking contacts has been experimentally verified in a 3 X 3 array format with all elements in the array exhibiting background limited infrared photodetector (BLIP) performance at 80 K. Performance issues such as response uniformity, pixel yield, fill factor, crosstalk, power dissipation, detector impedance, array architecture, and maximum array size are discussed in relation to the suitability of the proposed photoconductor structure for use in IRFPA modules. It is found that in many cases the proposed photoconductor technology has the potential to deliver significant advantages, such as higher yield, higher fill factor, better uniformity, less crosstalk, and larger potential array size, in comparison to an IRFPA design based on photovoltaic technology.

  16. High-gain and low-excess noise near-infrared single-photon avalanche detector arrays

    NASA Astrophysics Data System (ADS)

    Linga, Krishna; Yevtukhov, Yuriy; Liang, Bing

    2010-04-01

    We have designed and developed a new family of photodetectors and arrays with Internal Discrete Amplification (IDA) mechanism for the realization of very high gain and low excess noise factor in the visible and near infrared spectral regions. These devices surpass many limitations of the Single Photon Avalanche Photodetectors such as ultra low excess noise factor, very high gain, lower reset time (< 200 ns). These devices are very simple to operate in the non-gated mode under a constant dc bias voltage. Because of its unique characteristics of self-quenching and self-recovery, no external quenching circuit is needed. This unique feature of self quenching and self-recovery makes it simple to less complex readout integrated circuit to realize large format detector arrays. In this paper, we present the discrete amplification design approach used for the development of self reset, high gain photodetector arrays in the near infrared wavelength region. The demonstrated device performance far exceeds any available solid state Photodetectors in the near infrared wavelength range. These devices are ideal for researchers in the field of spectroscopy, industrial and scientific instrumentation, Ladar, quantum cryptography, night vision and other military, defense and aerospace applications.

  17. Multisoliton supercontinuum from a photonic-crystal fibre as a source of frequency-tunable megawatt femtosecond pulses in the infrared

    SciTech Connect

    Fedotov, I V; Fedotov, Andrei B; Zheltikov, Aleksei M; Voronin, A A; Shevandin, V S; Dukel'skii, K V

    2009-07-31

    We demonstrate a new method of generation of frequency-tunable megawatt femtosecond pulses in the infrared based on multisoliton supercontinuum generation in a large-mode-area photonic-crystal fibre (PCF) followed by the temporal compression of the PCF output. Photonic-crystal fibres with a core area of about 710 {mu}m{sup 2} are employed to convert microjoule femtosecond laser pulses with a spectrum centred at 1.39 {mu}m into pulses with a central wavelength of 1520 nm, a pulse width of 210 fs, and a peak power of about 1 MW. (special issue devoted to the 80th birthday of S.A. Akhmanov)

  18. Latest Developments in Long-Wavelength and Very-Long-Wavelength Infrared Detection with p-on- n HgCdTe

    NASA Astrophysics Data System (ADS)

    Baier, N.; Cervera, C.; Gravrand, O.; Mollard, L.; Lobre, C.; Destefanis, G.; Bourgeois, G.; Zanatta, J. P.; Boulade, O.; Moreau, V.

    2015-09-01

    We report recent developments at Commissariat à l'Energie Atomique-Laboratoire d'Electronique des Technologies de l'Information Infrared Laboratory on the processing and characterization of p-on- n HgCdTe (MCT) planar infrared focal plane arrays (FPAs) operating in the long-wavelength infrared (LWIR) and very-long-wavelength infrared (VLWIR) spectral bands. The active layers in these FPAs were grown by liquid phase epitaxy (LPE) on a lattice-matched CdZnTe substrate. This technological process results in lower dark current and lower serial resistance than for n-on- p vacancy-doped architecture and thus is better adapted for lower flux detection or higher operating temperature. This architecture was evaluated for space applications in the LWIR and VLWIR spectral bands with cutoff wavelengths from 10 to 17 μm at 78 K. Innovations have been introduced to the technological process to form a heterojunction by use of an LPE growth technique. The initial objective was to reduce the dark current at low temperatures, by reducing the transition temperature from diffusion-limited to depletion-limited dark current. Another advantage is that the wider bandgap obtained in the vicinity of the junction ensures less sensitivity to the defects present at the interface between MCT and passivation layers. Electro-optical characterization of p-on- n photodiodes was performed on quarter video graphics array format FPAs with 25 and 30 μm pixel pitches. The results revealed excellent operabilities in current and responsivity, with low dispersion, and noise limited by current shot noise. Studies performed on the dark current show that dark current densities at 78 K are consistent with the heuristic prediction law "Rule 07". Below this temperature, dark current varies as a pure diffusion current for a variety of devices from different manufacturers, introducing a temperature range limitation in the description of the "Rule 07" law.

  19. Mid-infrared quantum dot emitters utilizing planar photonic crystal technology.

    SciTech Connect

    Subramania,Ganapathi Subramanian; Lyo, Sungkwun Kenneth; Cederberg, Jeffrey George; Passmore, Brandon Scott; El-Kady, Ihab Fathy; Shaner, Eric Arthur

    2008-09-01

    The three-dimensional confinement inherent in InAs self-assembled quantum dots (SAQDs) yields vastly different optical properties compared to one-dimensionally confined quantum well systems. Intersubband transitions in quantum dots can emit light normal to the growth surface, whereas transitions in quantum wells emit only parallel to the surface. This is a key difference that can be exploited to create a variety of quantum dot devices that have no quantum well analog. Two significant problems limit the utilization of the beneficial features of SAQDs as mid-infrared emitters. One is the lack of understanding concerning how to electrically inject carriers into electronic states that allow optical transitions to occur efficiently. Engineering of an injector stage leading into the dot can provide current injection into an upper dot state; however, to increase the likelihood of an optical transition, the lower dot states must be emptied faster than upper states are occupied. The second issue is that SAQDs have significant inhomogeneous broadening due to the random size distribution. While this may not be a problem in the long term, this issue can be circumvented by using planar photonic crystal or plasmonic approaches to provide wavelength selectivity or other useful functionality.

  20. Photonically enabled Ka-band radar and infrared sensor subscale testbed

    NASA Astrophysics Data System (ADS)

    Lohr, Michele B.; Sova, Raymond M.; Funk, Kevin B.; Airola, Marc B.; Dennis, Michael L.; Pavek, Richard E.; Hollenbeck, Jennifer S.; Garrison, Sean K.; Conard, Steven J.; Terry, David H.

    2014-10-01

    A subscale radio frequency (RF) and infrared (IR) testbed using novel RF-photonics techniques for generating radar waveforms is currently under development at The Johns Hopkins University Applied Physics Laboratory (JHU/APL) to study target scenarios in a laboratory setting. The linearity of Maxwell's equations allows the use of millimeter wavelengths and scaled-down target models to emulate full-scale RF scene effects. Coupled with passive IR and visible sensors, target motions and heating, and a processing and algorithm development environment, this testbed provides a means to flexibly and cost-effectively generate and analyze multi-modal data for a variety of applications, including verification of digital model hypotheses, investigation of correlated phenomenology, and aiding system capabilities assessment. In this work, concept feasibility is demonstrated for simultaneous RF, IR, and visible sensor measurements of heated, precessing, conical targets and of a calibration cylinder. Initial proof-of-principle results are shown of the Ka-band subscale radar, which models S-band for 1/10th scale targets, using stretch processing and Xpatch models.

  1. Broadband three-photon near-infrared quantum cutting in Tm{sup 3+} singly doped YVO{sub 4}

    SciTech Connect

    Wang, Y. Z.; Yu, D. C.; Lin, H. H.; Ye, S.; Peng, M. Y.; Zhang, Q. Y.

    2013-11-28

    An efficient three-photon near-infrared (NIR) quantum cutting (QC) is reported in Tm{sup 3+} singly doped YVO{sub 4} polycrystalline phosphors, where an optimized content of Tm{sup 3+} is determined to be 1.0 mol. %. Upon the absorption of a visible photon around 473 nm, three NIR photons emitting at 1180, 1479, and 1800 nm can be obtained efficiently by the sequential three-step radiative transitions of Tm{sup 3+}. The underlying mechanisms are analyzed in terms of the steady and dynamic fluorescence spectra measurements. Internal quantum yield is calculated to be 161.8% as a theoretical value when luminescence quenching due to defect species can be overcome. In addition, the broadband ultraviolet (UV)-excited [VO{sub 4}]{sup 3−} can strongly sensitize the {sup 1}G{sub 4} level of Tm{sup 3+} in the wavelength range likely from 250 to 360 nm, greatly increasing the UV photo-response and NIR fluorescent intensity of Tm{sup 3+}. The further development of this broadband three-photon NIR QC material would explore the new route to improve the photo-response of novel photoelectronic devices, particularly in 250–360 nm.

  2. Photon-counting array detectors for space and ground-based studies at ultraviolet and vacuum ultraviolet /VUV/ wavelengths

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.; Bybee, R. L.

    1981-01-01

    The Multi-Anode Microchannel Arrays (MAMAs) are a family of photoelectric photon-counting array detectors, with formats as large as (256 x 1024)-pixels that can be operated in a windowless configuration at vacuum ultraviolet (VUV) and soft X-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. This paper describes the construction and modes of operation of (1 x 1024)-pixel and (24 x 1024)-pixel MAMA detector systems that are being built and qualified for use in sounding-rocket spectrometers for solar and stellar observations at wavelengths below 1300 A. The performance characteristics of the MAMA detectors at ultraviolet and VUV wavelengths are also described.

  3. Two-color two-photon excited fluorescence of indole: Determination of wavelength-dependent molecular parameters

    SciTech Connect

    Herbrich, Sebastian; Al-Hadhuri, Tawfik; Gericke, Karl-Heinz; Shternin, Peter S. Vasyutinskii, Oleg S.; Smolin, Andrey G.

    2015-01-14

    We present a detailed study of two-color two-photon excited fluorescence in indole dissolved in propylene glycol. Femtosecond excitation pulses at effective wavelengths from 268 to 293.33 nm were used to populate the two lowest indole excited states {sup 1}L{sub a} and {sup 1}L{sub b} and polarized fluorescence was then detected. All seven molecular parameters and the two-photon polarization ratio Ω containing information on two-photon absorption dynamics, molecular lifetime τ{sub f}, and rotation correlation time τ{sub rot} have been determined from experiment and analyzed as a function of the excitation wavelength. The analysis of the experimental data has shown that {sup 1}L{sub b}–{sup 1}L{sub a} inversion occurred under the conditions of our experiment. The two-photon absorption predominantly populated the {sup 1}L{sub a} state at all excitation wavelengths but in the 287–289 nm area which contained an absorption hump of the {sup 1}L{sub b} state 0-0 origin. The components of the two-photon excitation tensor S were analyzed giving important information on the principal tensor axes and absorption symmetry. The results obtained are in a good agreement with the results reported by other groups. The lifetime τ{sub f} and the rotation correlation time τ{sub rot} showed no explicit dependence on the effective excitation wavelength. Their calculated weighted average values were found to be τ{sub f} = 3.83 ± 0.14 ns and τ{sub rot} = 0.74 ± 0.06 ns.

  4. A short-wavelength infrared emitting multimodal probe for non-invasive visualization of phagocyte cell migration in living mice.

    PubMed

    Tsukasaki, Y; Komatsuzaki, A; Mori, Y; Ma, Q; Yoshioka, Y; Jin, T

    2014-11-28

    For the non-invasive visualization of cell migration in deep tissues, we synthesized a short-wavelength infrared (SWIR) emitting multimodal probe that contains PbS/CdS quantum dots, rhodamine 6G and iron oxide nanoparticles. This probe enables multimodal (SWIR fluorescence/magnetic resonance) imaging of phagocyte cell migration in living mice. PMID:25296382

  5. Measurement of the spectral signature of small carbon clusters at near and far infrared wavelengths

    NASA Technical Reports Server (NTRS)

    Tarter, J.; Saykally, R.

    1991-01-01

    A significant percentage of the carbon inventory of the circumstellar and interstellar media may be in the form of large refractory molecules (or small grains) referred to as carbon clusters. At the small end, uneven numbers of carbon atoms seem to be preferred, whereas above 12 atoms, clusters containing an even number of carbon atoms appear to be preferred in laboratory chemistry. In the lab, the cluster C-60 appears to be a particularly stable form and has been nicknamed Bucky Balls because of its resemblance to a soccer ball and to geodesic domes designed by Buckminster Fuller. In order to investigate the prevalence of these clusters, and their relationship to the polycyclic aromatic hydrocarbons (PAHs) that have become the newest focus of IR astronomy, it is necessary to determine the spectroscopic characteristics of these clusters at near and far infrared wavelengths. Described here is the construction of a near to far IR laser magnetic resonance spectrometer that has been built at the University of California Berkeley in order to detect and characterize these spectra. The equipment produces carbon clusters by laser evaporation of a graphitic target. The clusters are then cooled in a supersonic expansion beam in order to simulate conditions in the interstellar medium (ISM). The expansion beam feeds into the spectrometer chamber and permits concentrations of clusters sufficiently high as to permit ultra-high resolution spectroscopy at near and far IR wavelengths. The first successful demonstration of this apparatus occurred last year when the laboratory studies permitted the observational detection of C-5 in the stellar outflow surrounding IRC+10216 in the near-IR. Current efforts focus on reducing the temperature of the supersonic expansion beam that transport the C clusters evaporated from a graphite target into the spectrometer down to temperatures as low as 1 K.

  6. Small band gap superlattices as intrinsic long wavelength infrared detector materials

    NASA Technical Reports Server (NTRS)

    Smith, Darryl L.; Mailhiot, C.

    1990-01-01

    Intrinsic long wavelength (lambda greater than or equal to 10 microns) infrared (IR) detectors are currently made from the alloy (Hg, Cd)Te. There is one parameter, the alloy composition, which can be varied to control the properties of this material. The parameter is chosen to set the band gap (cut-off wavelength). The (Hg, Cd)Te alloy has the zincblend crystal structure. Consequently, the electron and light-hole effective masses are essentially inversely proportional to the band gap. As a result, the electron and light-hole effective masses are very small (M sub(exp asterisk)/M sub o approx. M sub Ih/M sub o approx. less than 0.01) whereas the heavy-hole effective mass is ordinary size (M sub hh(exp asterisk)/M sub o approx. 0.4) for the alloy compositions required for intrinsic long wavelength IR detection. This combination of effective masses leads to rather easy tunneling and relatively large Auger transition rates. These are undesirable characteristics, which must be designed around, of an IR detector material. They follow directly from the fact that (Hg, Cd)Te has the zincblend crystal structure and a small band gap. In small band gap superlattices, such as HgTe/CdTe, In(As, Sb)/InSb and InAs/(Ga,In)Sb, the band gap is determined by the superlattice layer thicknesses as well as by the alloy composition (for superlattices containing an alloy). The effective masses are not directly related to the band gap and can be separately varied. In addition, both strain and quantum confinement can be used to split the light-hole band away from the valence band maximum. These band structure engineering options can be used to reduce tunneling probabilities and Auger transition rates compared with a small band gap zincblend structure material. Researchers discuss the different band structure engineering options for the various classes of small band gap superlattices.

  7. All-optical modulation in Mid-Wavelength Infrared using porous Si membranes

    NASA Astrophysics Data System (ADS)

    Park, Sung Jin; Zakar, Ammar; Zerova, Vera L.; Chekulaev, Dimitri; Canham, Leigh T.; Kaplan, Andre

    2016-07-01

    We demonstrate for the first time the possibility of all-optical modulation of self-standing porous Silicon (pSi) membrane in the Mid-Wavelength Infrared (MWIR) range using femtosecond pump-probe techniques. To study optical modulation, we used pulses of an 800 nm, 60 femtosecond for pump and a MWIR tunable probe in the spectral range between 3.5 and 4.4 μm. We show that pSi possesses a natural transparency window centred around 4 μm. Yet, about 55% of modulation contrast can be achieved by means of optical excitation at the pump power of 60 mW (4.8 mJ/cm2). Our analysis shows that the main mechanism of the modulation is interaction of the MWIR signal with the free charge carrier excited by the pump. The time-resolved measurements showed a sub-picosecond rise time and a recovery time of about 66 ps, which suggests a modulation speed performance of ~15 GHz. This optical modulation of pSi membrane in MWIR can be applied to a variety of applications such as thermal imaging and free space communications.

  8. Automated model-based calibration of short-wavelength infrared (SWIR) imaging spectrographs.

    PubMed

    Kosec, Matjaž; Bürmen, Miran; Tomaževič, Dejan; Pernuš, Franjo; Likar, Boštjan

    2012-10-01

    Among the variety of available hyperspectral imaging systems, the line-scan technique stands out for its short acquisition time and good signal-to-noise ratio. However, due to imperfections in the camera lens and, in particular, optical components of the imaging spectrograph, the acquired images are spatially and spectrally distorted, which can significantly degrade the accuracy of the subsequent hyperspectral image analysis. In this work, we propose and evaluate an automated method for correction of spatial and spectral distortions introduced by a line-scan hyperspectral imaging system operating in the short wavelength infrared (SWIR) spectral range from 1000 nm to 2500 nm. The proposed method is based on non-rigid registration of the distorted and reference images corresponding to two passive calibration objects. The results of the validation show that the proposed method is accurate, efficient, and applicable for calibration of line-scan hyperspectral imaging systems. Moreover, the design of the method and of the calibration objects allows integration with systems operating in diffuse reflectance or transmittance modes. PMID:23031695

  9. Design study of nanograting-based surface plasmon resonance biosensor in the near-infrared wavelength.

    PubMed

    Tahmasebpour, M; Bahrami, M; Asgari, A

    2014-03-01

    A key issue with surface plasmon resonance (SPR) biosensors, which are the focus of many researchers, is improving their sensitivity to detect lower amounts of analyte in a solution. Most SPR developments have focused on the grating-based sensitivity-enhancement approach. In addition to sensitivity, a substantial enhancement of other sensor characteristics such as resolution and signal-to-noise ratio (SNR) is desired for designing a practical sensor. So, in this paper, the characteristics of surface plasmon polaritons sustained by 1D subwavelength metallic gratings on a thin metal slab (under the Krestchmann configuration) have been investigated numerically for the analyte-ligand interactions detection. Effects of different structural parameters, such as grating period, grating depth, metal film thickness, and fill factor have been evaluated on the sensor sensitivity as well as resolution and SNR. Numerical results indicate that the sensor working in the near-infrared wavelength has a better performance than that in the visible one. The result of numerical investigation has been used to design an optimized sensor with the best figure of merit. PMID:24663375

  10. Design of reimaging F/1.0 long-wavelength infrared optical system

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Liu, Bo; Jia, Hong-guang

    2011-08-01

    A reimaging F/1.0 long-wavelength infrared optical system is proposed. The design has a flexible opto-mechanical layout. The design process is as follows. Firstly, the catadioptric reimaging system consists of two reflecting mirrors and a relay lenses. Two reflecting mirrors make up of the first imaging system and are therefore free of chromatic aberrations, while low dispersion lenses were used in the reimaging system, so the optical system do not need achromatic design for a high image quality. Then, to correct high-order aberrations resulting from large relative aperture, more parameters need to be used with aspheric or diffractive surfaces due to modern optic technology development. Here, aspheric is selected for easily manufacture. Finally, the design is completed with the help of ZEMAX software. The effective focal length of the objective is 120mm and the field of view (FOV) is 4°. The simulated final design shows adequate image quality and the modulation transfer function (MTF) is close to diffraction limit. The effect of the surrounding environmental temperature is analyzed using the concept of thermal defocusing, and the thermal compensation is discussed.

  11. All-optical modulation in Mid-Wavelength Infrared using porous Si membranes.

    PubMed

    Park, Sung Jin; Zakar, Ammar; Zerova, Vera L; Chekulaev, Dimitri; Canham, Leigh T; Kaplan, Andre

    2016-01-01

    We demonstrate for the first time the possibility of all-optical modulation of self-standing porous Silicon (pSi) membrane in the Mid-Wavelength Infrared (MWIR) range using femtosecond pump-probe techniques. To study optical modulation, we used pulses of an 800 nm, 60 femtosecond for pump and a MWIR tunable probe in the spectral range between 3.5 and 4.4 μm. We show that pSi possesses a natural transparency window centred around 4 μm. Yet, about 55% of modulation contrast can be achieved by means of optical excitation at the pump power of 60 mW (4.8 mJ/cm(2)). Our analysis shows that the main mechanism of the modulation is interaction of the MWIR signal with the free charge carrier excited by the pump. The time-resolved measurements showed a sub-picosecond rise time and a recovery time of about 66 ps, which suggests a modulation speed performance of ~15 GHz. This optical modulation of pSi membrane in MWIR can be applied to a variety of applications such as thermal imaging and free space communications. PMID:27440224

  12. Modeling of scattering and absorption by nonspherical cirrus ice particles at thermal infrared wavelengths

    SciTech Connect

    Fu, Q.; Sun, W.B.; Yang, P.

    1999-08-15

    This paper examines a number of commonly used methods for the calculation of the scattering and absorption properties of nonspherical ice crystals at thermal infrared wavelengths. It is found that, for randomly oriented nonspherical particles, Mie theory using equivalent ice spheres tends to overestimate the absorption efficiency while the anomalous diffraction theory (ADT) and the geometric optics method (GOM) tend to underestimate it. The absorption efficiency is not sensitive to the particle shape when the size parameter is large. Herein a composite scheme is used that is valid for nonspherical particles with a wide range of size parameters. This scheme is a composite of Mie theory, GOM, and ADT to fit the single-scattering properties of hexagonal particles derived from the GOM for large size parameters and the finite-difference time domain technique for small size parameters. Applying this composite technique, errors in the broadband emissivity of cirrus clouds associated with conventional approaches are examined. It is shown that, when the projected area is preserved, Mie results overestimate the emissivity of cirrus clouds while, when the volume is preserved, Mie results underestimate the emissivity. Mie theory yields the best results when both projected area and volume are preserved (the relative errors are less than 10%). It is also shown that the ADT underestimates cirrus cloud emissivity. In some cases, the relative errors can be as large as 20%. The errors in the GOM are also significant and are largely a result of nonspherical particles with size parameters smaller than 40.

  13. All-optical modulation in Mid-Wavelength Infrared using porous Si membranes

    PubMed Central

    Park, Sung Jin; Zakar, Ammar; Zerova, Vera L.; Chekulaev, Dimitri; Canham, Leigh T.; Kaplan, Andre

    2016-01-01

    We demonstrate for the first time the possibility of all-optical modulation of self-standing porous Silicon (pSi) membrane in the Mid-Wavelength Infrared (MWIR) range using femtosecond pump-probe techniques. To study optical modulation, we used pulses of an 800 nm, 60 femtosecond for pump and a MWIR tunable probe in the spectral range between 3.5 and 4.4 μm. We show that pSi possesses a natural transparency window centred around 4 μm. Yet, about 55% of modulation contrast can be achieved by means of optical excitation at the pump power of 60 mW (4.8 mJ/cm2). Our analysis shows that the main mechanism of the modulation is interaction of the MWIR signal with the free charge carrier excited by the pump. The time-resolved measurements showed a sub-picosecond rise time and a recovery time of about 66 ps, which suggests a modulation speed performance of ~15 GHz. This optical modulation of pSi membrane in MWIR can be applied to a variety of applications such as thermal imaging and free space communications. PMID:27440224

  14. 256×1 element linear InGaAs short wavelength near-infrared detector arrays

    NASA Astrophysics Data System (ADS)

    Li, Xue; Tang, Hengjing; Fan, Guangyu; Liu, Dafu; Shao, Xiumei; Zhang, Yonggang; Zhang, Haiyan; Chen, Xinyu; Zhu, Sangen; Gong, Haimei; Fang, Jiaxiong

    2008-03-01

    256×1 element linear InGaAs detector arrays assembly have been fabricated for the short wave infrared band(0.9~1.7μm), including the detector, CMOS readout circuits, thermoelectric cooler in a sealed package. The InGaAs detectors were achieved by mesa structure on the p-InP/i-InGaAs/n-InP double hetero-structure epitaxial material. 256×1 element linear InGaAs detectors were wire-bonded to 128×1 element odd and even ROIC, which were packaged in a dual-in-line package by parallel sealing. The characteristics of detectors and detector arrays module were investigated at the room temperature. The detector shows response peak at 1.62μm with 50% cutoff wavelength of 1.73μm and average R0A with 5.02KΩ•cm2. Response non-uniformity and average peak detectivity of 256×1 element linear InGaAs detector arrays are 3.10% and 1.38×10 12cmHz 1/2/W, respectively.

  15. Recent progress in MOCVD growth for thermoelectrically cooled HgCdTe medium wavelength infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Gawron, W.; Martyniuk, P.; Kębłowski, A.; Kolwas, K.; Stępień, D.; Piotrowski, J.; Madejczyk, P.; Pędzińska, M.; Rogalski, A.

    2016-04-01

    The authors report on advanced metalorganic chemical vapour deposition (MOCVD) of Hg1-xCdxTe (HgCdTe) structures for high operating temperature, medium wavelength infrared (MWIR) detector application. MOCVD technology with wide range of composition and donor/acceptor doping and without post grown annealing was proved to be an excellent tool for HgCdTe heterostructure epitaxial growth used for uncooled photodetector design. The interdiffused multilayer process (IMP) technique was applied for the HgCdTe deposition. HgCdTe epilayers were grown at 350 °C with Hg source kept at 210 °C. The II/VI mole ratio was assumed in the range from 1.5 to 3 during CdTe/HgTe cycles of the IMP process. The MWIR detectors grown by MOCVD exhibit detectivity ∼7.3 × 1011 Jones at λPEAK = 3.5 μm and T = 230 K being determined by background limited photodetector (BLIP) condition.

  16. Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

    SciTech Connect

    Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Sargent, Edward H.; Kinge, Sachin

    2015-10-12

    Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO{sub 2} layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10{sup −2} A W{sup −1} and a shot-derived specific detectivity of 3 × 10{sup 9} Jones at 1530 nm wavelength.

  17. Exploring the transition to planetary nebula using high-resolution techniques at infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Wendolyn Blanco Cárdenas, Mónica

    2015-08-01

    A planetary nebula (PN) is the ionised envelope surrounding a white dwarf, the final fate of low- and intermediate-mass stars. This stellar phase is also important for its contribution to the interstellar medium, when PNe drive out s-process elements, molecules as well as different dust species, the building blocks of life. One of the most discussed topics in the PNe research field is their huge variety of morphologies and how the more complex forms are sculpted. The theoretical models predict the existence of collimating agents such as disks (steady and/or rotating), jets, and binary systems to sculpt these perplexing morphologies. However, the observations able to detect these shaping engines are often quite difficult to accomplish. Furthermore, the transition to PN hides the clues of these process, that is, when the AGB, post-AGBs, proto-PN, and the circumstellar environments of young PNe are compact and embeded in dust. In this work, we present our results implementing observational techniques and different analysis to inspect and resolve these structures by means of high-resolution imaging, high- and low-resolution spectroscopy at infrared wavelengths and using two VLT instruments: CRIRES (near-IR) and VISIR (mid-IR).

  18. InAs/GaSb superlattice detectors for the long-wavelength infrared regime

    NASA Astrophysics Data System (ADS)

    Rehm, Robert; Masur, Michael; Schmitz, Johannes; Walther, Martin

    2014-06-01

    To enable higher operating temperatures in InAs/GaSb superlattice detectors for the long-wavelength infrared atmospheric window at 8-12 μm, a reduction of the bulk dark current density is indispensable. To reduce the dark current of conventional homojunction pin-diode device designs, bandstructure-engineering of the active region is considered most promising. So far, several successful device concepts have been demonstrated, yet they all rely on the inclusion of Aluminum within the active layers. Driven by manufacturing aspects we propose an Al-free heterojunction device concept that is based on a p+-doped InAs/GaSb superlattice absorber layer combined with an adjacent N--doped high gap region, which again is realized with an InAs/GaSb superlattice. To calculate the superlattice band gap and the position of the conduction band edge at the heterojunction we employ the Superlattice Empirical Pseudopotential Method. With a series of three heterojunction p+N- InAs/GaSb superlattice devices with an absorber band gap of 124 meV (10.0 μm) we give a first proof of the advocated device concept.

  19. Near-infrared photonic energy penetration: can infrared phototherapy effectively reach the human brain?

    PubMed Central

    Henderson, Theodore A; Morries, Larry D

    2015-01-01

    Traumatic brain injury (TBI) is a growing health concern effecting civilians and military personnel. Research has yielded a better understanding of the pathophysiology of TBI, but effective treatments have not been forthcoming. Near-infrared light (NIR) has shown promise in animal models of both TBI and stroke. Yet, it remains unclear if sufficient photonic energy can be delivered to the human brain to yield a beneficial effect. This paper reviews the pathophysiology of TBI and elaborates the physiological effects of NIR in the context of this pathophysiology. Pertinent aspects of the physical properties of NIR, particularly in regards to its interactions with tissue, provide the background for understanding this critical issue of light penetration through tissue. Our recent tissue studies demonstrate no penetration of low level NIR energy through 2 mm of skin or 3 cm of skull and brain. However, at 10–15 W, 0.45%–2.90% of 810 nm light penetrated 3 cm of tissue. A 15 W 810 nm device (continuous or non-pulsed) NIR delivered 2.9% of the surface power density. Pulsing at 10 Hz reduced the dose of light delivered to the surface by 50%, but 2.4% of the surface energy reached the depth of 3 cm. Approximately 1.22% of the energy of 980 nm light at 10–15 W penetrated to 3 cm. These data are reviewed in the context of the literature on low-power NIR penetration, wherein less than half of 1% of the surface energy could reach a depth of 1 cm. NIR in the power range of 10–15 W at 810 and 980 nm can provide fluence within the range shown to be biologically beneficial at 3 cm depth. A companion paper reviews the clinical data on the treatment of patients with chronic TBI in the context of the current literature. PMID:26346298

  20. Infrared transparent graphene heater for silicon photonic integrated circuits.

    PubMed

    Schall, Daniel; Mohsin, Muhammad; Sagade, Abhay A; Otto, Martin; Chmielak, Bartos; Suckow, Stephan; Giesecke, Anna Lena; Neumaier, Daniel; Kurz, Heinrich

    2016-04-18

    Thermo-optical tuning of the refractive index is one of the pivotal operations performed in integrated silicon photonic circuits for thermal stabilization, compensation of fabrication tolerances, and implementation of photonic operations. Currently, heaters based on metal wires provide the temperature control in the silicon waveguide. The strong interaction of metal and light, however, necessitates a certain gap between the heater and the photonic structure to avoid significant transmission loss. Here we present a graphene heater that overcomes this constraint and enables an energy efficient tuning of the refractive index. We achieve a tuning power as low as 22 mW per free spectral range and fast response time of 3 µs, outperforming metal based waveguide heaters. Simulations support the experimental results and suggest that for graphene heaters the spacing to the silicon can be further reduced yielding the best possible energy efficiency and operation speed. PMID:27137229

  1. Photon sorting in the near field using subwavelength cavity arrays in the near-infrared

    SciTech Connect

    Mandel, Isroel M. Lansey, Eli; Gollub, Jonah N.; Sarantos, Chris H.; Akhmechet, Roman; Golovin, Andrii B.; Crouse, David T.

    2013-12-16

    A frequency selective metasurface capable of sorting photons in the near-infrared spectral range is designed, fabricated, and characterized. The metasurface, a periodic array of dielectric cylindrical cavities in a gold film, localizes and transmits light of two spectral frequency bands into spatially separated cavities, resulting in near-field light splitting. The design and fabrication methodologies of the metasurface are discussed. The transmittance and photon sorting properties of the designed structure is simulated numerically and the measured transmission is presented.

  2. Design of the First Infrared Beamline at the Siam Photon Laboratory

    SciTech Connect

    Pattanasiriwisawa, W.; Songsiriritthigul, P.; Dumas, P.

    2010-06-23

    This report presents the optical design and optical simulations for the first infrared beamline at the Siam Photon Laboratory. The beamline collects the edge radiation and bending magnet radiation, producing from the BM4 bending magnet of the 1.2 GeV storage ring of the Siam Photon Source. The optical design is optimized for the far- to mid-infrared spectral range (4000-100 cm{sup -1}) for microspectroscopic applications. The optical performance has been examined by computer simulations.

  3. Sculpting narrowband Fano resonances inherent in the large-area mid-infrared photonic crystal microresonators for spectroscopic imaging

    PubMed Central

    Liu, Jui-Nung; Schulmerich, Matthew V.; Bhargava, Rohit; Cunningham, Brian T.

    2014-01-01

    Fourier transform infrared (FT-IR) imaging spectrometers are almost universally used to record microspectroscopic imaging data in the mid-infrared (mid-IR) spectral region. While the commercial standard, interferometry necessitates collection of large spectral regions, requires a large data handling overhead for microscopic imaging and is slow. Here we demonstrate an approach for mid-IR spectroscopic imaging at selected discrete wavelengths using narrowband resonant filtering of a broadband thermal source, enabled by high-performance guided-mode Fano resonances in one-layer, large-area mid-IR photonic crystals on a glass substrate. The microresonant devices enable discrete frequency IR (DF-IR), in which a limited number of wavelengths that are of interest are recorded using a mechanically robust instrument. This considerably simplifies instrumentation as well as overhead of data acquisition, storage and analysis for large format imaging with array detectors. To demonstrate the approach, we perform DF-IR spectral imaging of a polymer USAF resolution target and human tissue in the C−H stretching region (2600−3300 cm−1). DF-IR spectroscopy and imaging can be generalized to other IR spectral regions and can serve as an analytical tool for environmental and biomedical applications. PMID:25089433

  4. Sculpting narrowband Fano resonances inherent in the large-area mid-infrared photonic crystal microresonators for spectroscopic imaging.

    PubMed

    Liu, Jui-Nung; Schulmerich, Matthew V; Bhargava, Rohit; Cunningham, Brian T

    2014-07-28

    Fourier transform infrared (FT-IR) imaging spectrometers are almost universally used to record microspectroscopic imaging data in the mid-infrared (mid-IR) spectral region. While the commercial standard, interferometry necessitates collection of large spectral regions, requires a large data handling overhead for microscopic imaging and is slow. Here we demonstrate an approach for mid-IR spectroscopic imaging at selected discrete wavelengths using narrowband resonant filtering of a broadband thermal source, enabled by high-performance guided-mode Fano resonances in one-layer, large-area mid-IR photonic crystals on a glass substrate. The microresonant devices enable discrete frequency IR (DF-IR), in which a limited number of wavelengths that are of interest are recorded using a mechanically robust instrument. This considerably simplifies instrumentation as well as overhead of data acquisition, storage and analysis for large format imaging with array detectors. To demonstrate the approach, we perform DF-IR spectral imaging of a polymer USAF resolution target and human tissue in the C-H stretching region (2600-3300 cm(-1)). DF-IR spectroscopy and imaging can be generalized to other IR spectral regions and can serve as an analytical tool for environmental and biomedical applications. PMID:25089433

  5. Satellite laser ranging using superconducting nanowire single-photon detectors at 1064  nm wavelength.

    PubMed

    Xue, Li; Li, Zhulian; Zhang, Labao; Zhai, Dongsheng; Li, Yuqiang; Zhang, Sen; Li, Ming; Kang, Lin; Chen, Jian; Wu, Peiheng; Xiong, Yaoheng

    2016-08-15

    Satellite laser ranging operating at 1064 nm wavelength using superconducting nanowire single-photon detectors (SNSPDs) is successfully demonstrated. A SNSPD with an intrinsic quantum efficiency of 80% and a dark count rate of 100 cps at 1064 nm wavelength is developed and introduced to Yunnan Observatory in China. With improved closed-loop telescope systems (field of view of about 26''), satellites including Cryosat, Ajisai, and Glonass with ranges of 1600 km, 3100 km, and 19,500 km, respectively, are experimentally ranged with mean echo rates of 1200/min, 4200/min, and 320/min, respectively. To the best of our knowledge, this is the first demonstration of laser ranging for satellites using SNSPDs at 1064 nm wavelength. Theoretical analysis of the detection efficiency and the mean echo rate for typical satellites indicate that it is possible for a SNSPD to range satellites from low Earth orbit to geostationary Earth orbit. PMID:27519105

  6. Compact Mach-Zehnder interferometer based on photonic crystal fiber and its application in switchable multi-wavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Chen, Weiguo; Lou, Shuqin; Wang, Liwen; Li, Honglei; Guo, Tieying; Jian, Shuisheng

    2009-08-01

    The compact Mach-Zehnder interferometer is proposed by splicing a section of photonic crystal fiber (PCF) and two pieces of single mode fiber (SMF) with the air-holes of PCF intentionally collapsed in the vicinity of the splices. The depedence of the fringe spacing on the length of PCF is investigated. Based on the Mach-Zehnder interferometer as wavelength-selective filter, a switchable dual-wavelength fiber ring laser is demonstrated with a homemade erbiumdoped fiber amplifier (EDFA) as the gain medium at room temperature. By adjusting the states of the polarization controller (PC) appropriately, the laser can be switched among the stable single-and dual -wavelength lasing operations by exploiting polarization hole burning (PHB) effect.

  7. Towards nano-scale photonics with micro-scale photons: the opportunities and challenges of mid-infrared plasmonics

    NASA Astrophysics Data System (ADS)

    Law, Stephanie; Podolskiy, Viktor; Wasserman, Daniel

    2013-04-01

    Surface plasmon polaritons and their localized counterparts, surface plasmons, are widely used at visible and near-infrared (near-IR) frequencies to confine, enhance, and manipulate light on the subwavelength scale. At these frequencies, surface plasmons serve as enabling mechanisms for future on-chip communications architectures, high-performance sensors, and high-resolution imaging and lithography systems. Successful implementation of plasmonics-inspired solutions at longer wavelengths, in the mid-infrared (mid-IR) frequency range, would benefit a number of highly important technologies in health- and defense-related fields that include trace-gas detection, heat-signature sensing, mimicking, and cloaking, and source and detector development. However, the body of knowledge of visible/near-IR frequency plasmonics cannot be easily transferred to the mid-IR due to the fundamentally different material response of metals in these two frequency ranges. Therefore, mid-IR plasmonic architectures for subwavelength light manipulation require both new materials and new geometries. In this work we attempt to provide a comprehensive review of recent approaches to realize nano-scale plasmonic devices and structures operating at mid-IR wavelengths. We first discuss the motivation for the development of the field of mid-IR plasmonics and the fundamental differences between plasmonics in the mid-IR and at shorter wavelengths. We then discuss early plasmonics work in the mid-IR using traditional plasmonic metals, illuminating both the impressive results of this work, as well as the challenges arising from the very different behavior of metals in the mid-IR, when compared to shorter wavelengths. Finally, we discuss the potential of new classes of mid-IR plasmonic materials, capable of mimicking the behavior of traditional metals at shorter wavelengths, and allowing for true subwavelength, and ultimately, nano-scale confinement at long wavelengths.

  8. Surface Compositional Units on Mercury from Spectral Reflectance at Ultraviolet to Near-infrared Wavelengths

    NASA Astrophysics Data System (ADS)

    Izenberg, N. R.; Holsclaw, G. M.; Domingue, D. L.; McClintock, W. E.; Klima, R. L.; Blewett, D. T.; Helbert, J.; Head, J. W.; Sprague, A. L.; Vilas, F.; Solomon, S. C.

    2012-12-01

    The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft has been acquiring reflectance spectra of Mercury's surface for over 16 months. The Visible and Infrared Spectrograph (VIRS) component of MASCS has accumulated a global data set of more than 2 million spectra over the wavelength range 300-1450 nm. We have derived a set of VIRS spectral units (VSUs) from the following spectral parameters: visible brightness (R575: reflectance at 575 nm); visible/near-infrared reflectance ratio (VISr: reflectance at 415 nm to that at 750 nm); and ultraviolet reflectance ratio (UVr: reflectance at 310 nm to that at 390 nm). Five broad, slightly overlapping VSUs may be distinguished from these parameters. "Average VSU" areas have spectral parameters close to mean global values. "Dark blue VSU" areas have spectra with low R575 and high UVr. "Red VSU" areas have spectra with low UVr and higher VISr and R575 than average. "Intermediate VSU" areas have spectra with higher VISr than VSU red, generally higher R575, and a wide range of UVr. "Bright VSU" areas have high R575 and VISr and intermediate UVr. Several units defined by morphological or multispectral criteria correspond to specific VSUs, including low-reflectance material (dark blue VSU), pyroclastic deposits (red VSU), and hollows (intermediate VSU), but these VSUs generally include other types of areas as well. VSU definitions are complementary to those obtained by unsupervised clustering analysis. The global distribution of VIRS spectral units provides new information on Mercury's geological evolution. Much of Mercury's northern volcanic plains show spectral properties ranging from those of average VSU to those of red VSU, as does a large region in the southern hemisphere centered near 50°S, 245°E. Dark blue VSU material is widely distributed, with concentrations south of the northern plains, around the Rembrandt and

  9. Carcinogenic damage to deoxyribonucleic acid is induced by near-infrared laser pulses in multiphoton microscopy via combination of two- and three-photon absorption

    NASA Astrophysics Data System (ADS)

    Nadiarnykh, Oleg; Thomas, Giju; Van Voskuilen, Johan; Sterenborg, Henricus J. C. M.; Gerritsen, Hans C.

    2012-11-01

    Nonlinear optical imaging modalities (multiphoton excited fluorescence, second and third harmonic generation) applied in vivo are increasingly promising for clinical diagnostics and the monitoring of cancer and other disorders, as they can probe tissue with high diffraction-limited resolution at near-infrared (IR) wavelengths. However, high peak intensity of femtosecond laser pulses required for two-photon processes causes formation of cyclobutane-pyrimidine-dimers (CPDs) in cellular deoxyribonucleic acid (DNA) similar to damage from exposure to solar ultraviolet (UV) light. Inaccurate repair of subsequent mutations increases the risk of carcinogenesis. In this study, we investigate CPD damage that results in Chinese hamster ovary cells in vitro from imaging them with two-photon excited autofluorescence. The CPD levels are quantified by immunofluorescent staining. We further evaluate the extent of CPD damage with respect to varied wavelength, pulse width at focal plane, and pixel dwell time as compared with more pronounced damage from UV sources. While CPD damage has been expected to result from three-photon absorption, our results reveal that CPDs are induced by competing two- and three-photon absorption processes, where the former accesses UVA absorption band. This finding is independently confirmed by nonlinear dependencies of damage on laser power, wavelength, and pulse width.

  10. Tunable and switchable multi-wavelength fiber laser based on semiconductor optical amplifier and twin-core photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Kim, Bongkyun; Han, Jihee; Chung, Youngjoo

    2012-02-01

    Multi-wavelength fiber lasers have attracted a lot of interest, recently, because of their potential applications in wavelength-division-multiplexing (WDM) systems, optical fiber sensing, and fiber-optics instruments, due to their numerous advantages such as multiple wavelength operation, low cost, and compatibility with the fiber optic systems. Semiconductor optical amplifier (SOA)-based multi-wavelength fiber lasers exhibit stable operation because of the SOA has the property of primarily inhomogeneous broadening and thus can support simultaneous oscillation of multiple lasing wavelengths. In this letter, we propose and experimentally demonstrate a switchable multi-wavelength fiber laser employing a semiconductor optical amplifier and twin-core photonic crystal fiber (TC-PCF) based in-line interferometer comb filter. The fabricated two cores are not symmetric due to the associated fiber fabrication process such as nonuniform heat gradient in furnace and asymmetric microstructure expansion during the gas pressurization which results in different silica strut thickness and core size. The induced asymmetry between two cores considerably alters the linear power transfer, by seriously reducing it. These nominal twin cores form effective two optical paths and associated effective refractive index difference. The in-fiber comb filter is effectively constructed by splicing a section of TC-PCF between two single mode fibers (SMFs). The proposed laser can be designed to operate in stable multi-wavelength lasing states by adjusting the states of the polarization controller (PC). The lasing modes are switched by varying the state of PC and the change is reversible. In addition, we demonstrate a tunable multi-wavelength fiber laser operation by applying temperature changes to TC-PCF in the multi-channel filter.

  11. Mid-infrared wavelength- and frequency-modulation spectroscopy with a pump-modulated singly-resonant optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Lindsay, I. D.; Groß, P.; Lee, C. J.; Adhimoolam, B.; Boller, K.-J.

    2006-12-01

    We describe the implementation of the wavelength- and frequency-modulation spectroscopy techniques using a singly-resonant optical parametric oscillator (OPO) pumped by a fiber-amplified diode laser. Frequency modulation of the diode laser was transferred to the OPO’s mid-infrared idler output, avoiding the need for external modulation devices. This approach thus provides a means of implementing these important techniques with powerful, widely tunable, mid-infrared sources while retaining the simple, flexible modulation properties of diode lasers.

  12. A near-infrared 64-pixel superconducting nanowire single photon detector array with integrated multiplexed readout

    SciTech Connect

    Allman, M. S. Verma, V. B.; Stevens, M.; Gerrits, T.; Horansky, R. D.; Lita, A. E.; Mirin, R.; Nam, S. W.; Marsili, F.; Beyer, A.; Shaw, M. D.; Kumor, D.

    2015-05-11

    We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon detectors optimized for high detection efficiency in the near-infrared range. An integrated, readily scalable, multiplexed readout scheme is employed to reduce the number of readout lines to 16. The cryogenic, optical, and electronic packaging to read out the array as well as characterization measurements are discussed.

  13. Near-infrared Single-photon-counting Detectors for Free-space Laser Receivers

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.; Sun, Xiaoli; Hasselbrack, William; Wu, Stewart; Waczynski, Augustyn; Miko, Laddawan

    2007-01-01

    We compare several photon-counting detector technologies for use as near-infrared timeresolved laser receivers in science instrument, communication and navigation systems. The key technologies are InGaAs(P) photocathode hybrid photomultiplier tubes and InGaAs(P) and HgCdTe avalanche photodiodes. We discuss recent experimental results and application.

  14. Efficient light emitting diodes by photon recycling and their application in pixelless infrared imaging devices

    NASA Astrophysics Data System (ADS)

    Dupont, E.; Chiu, S.

    2000-02-01

    The success of the pixelless imaging concept using a quantum well infrared photodetector integrated with a light emitting diode (QWIP-LED) depends critically on the extent of spatial lateral spreading of both photocurrent generated in the QWIP and near infrared (NIR) photons emitted by the LED as they escape from the device layers. According to the photon recycling model proposed by Schnitzer et al. [Appl. Phys. Lett. 62, 131 (1993)] there appears to be a trade-off between a high LED external quantum efficiency and a small photon lateral spread, the former being a necessary condition for achieving high detector sensitivity. This lateral spreading due to multireflections and reincarnations of the NIR photons could potentially degrade the image quality or resolution of the device. By adapting Schnitzer's model to the QWIP-LED structure, we have identified device parameters that could potentially influence the NIR photon lateral spread and the LED external efficiency. In addition, we have developed a simple sequential model to estimate the crosstalk between the incoming far infrared image and the up-converted NIR image. We have found that the thickness of the LED is an important parameter that needs to be optimized in order to maximize the external efficiency and to minimize the crosstalk. A 6000-Å-thick LED active layer should give a resolution of ˜30 μm and an external efficiency of ˜10%.

  15. Long-Wavelength Infrared Sensing by Cytochrome C Protein Thin Film Deposited by the Spin Coating Method

    PubMed Central

    Lai, Bo-Yu; Chu, Chung-Hao; Su, Guo-Dung John

    2013-01-01

    High infrared absorption, large temperature coefficient of resistance (TCR) and small 1/f noise are preferred characteristics for sensing materials used in bolometers. In this paper, we discuss a cytochrome c protein as a potential sensing material for long-wavelength bolometers. We simulated and experimentally proved high infrared absorption of cytochrome c in the wavelength between 8 μm and 14 μm. Cytochrome c thin films were deposited on a hydrophilic surface using the spin coating method. The resistance variation with temperature is measured and we show that the TCR of cytochrome c thin films is consistently higher than 20%. The measured values of 1/f noise were as low as 2.33 × 10−13 V2/Hz at 60 Hz. Finally, we test the reliability of cytochrome c by measuring the resistance changes over time under varying conditions. We found that cytochrome c thin films deteriorated significantly without appropriate packaging. PMID:24264331

  16. Simultaneous seeing measurement through the Subaru Telescope in the visible and near-infrared bands for the wavelength dependence evaluation

    NASA Astrophysics Data System (ADS)

    Oya, Shin; Terada, Hiroshi; Hayano, Yutaka; Watanabe, Makoto; Hattori, Masayuki; Minowa, Yosuke

    2016-07-01

    Stellar images have been obtained under natural seeing at visible and near-infrared wavelengths simultaneously through the Subaru Telescope at Mauna Kea. The image quality is evaluated by the full-width at the half-maximum (FWHM) of the stellar images. The observed ratio of FWHM in the V-band to the K-band is 1.54 ± 0.17 on average. The ratio shows tendency to decrease toward bad seeing as expected from the outer scale influence, though the number of the samples is still limited. The ratio is important for simulations to evaluate the performance of a ground-layer adaptive optics system at near-infrared wavelengths based on optical seeing statistics. The observed optical seeing is also compared with outside seeing to estimate the dome seeing of the Subaru Telescope.

  17. Infrared Pulsed Laser Deposition: Applications in Photonics and Biomedical Technologies

    NASA Astrophysics Data System (ADS)

    Haglund, Richard

    2006-04-01

    Resonant infrared pulsed-laser deposition (RIR-PLD) shows significant promise for synthesizing thin films of small organic molecules, thermoplastic and thermosetting polymers and biopolymers, without compromising structure or functionality. This contrasts with most attempts at UV-PLD of organic materials, which have often been accompanied by severe photochemical or photothermal degradation of the ablated material. Representative recent successes in RIR-PLD include deposition of: polymers for light emission and hole transport; functionalized polymers and nanoparticles for chemical and biological sensing; and biocompatible polymers suitable for coating medical devices or drug-delivery vehicles. Plume imaging and various other optical- and mass-spectroscopy experiments appear to confirm that polymers or organic molecules ablated by resonant infrared laser irradiation experience a high spatial and temporal density of vibrational excitation, but tend to remain in the electronic ground state. The mechanism of RIR-PLD is observed to depend on the anharmonicity of the mid-infrared absorption modes, their finite relaxation time, mode-specific nonlinear absorption, and rapid changes in polymer viscosity as a function of temperature. Many of the RIR-PLD experiments to date were carried out using a tunable, mid-infrared, picosecond free-electron laser. However, if RIR-PLD is to become a practical tool for making organic thin films, it will be necessary to develop more conventional lasers that can achieve a similar combination of high pulse intensity, low pulse energy, high pulse-repetition frequency and moderate average power. In conclusion, the prospects for developing precisely such table-top RIR-PLD systems will be discussed.

  18. Sub-wavelength focusing of cylindrical vector beams by a 1D metallic photonic crystal plano-concave lens

    NASA Astrophysics Data System (ADS)

    Zhong, Yi; Wang, Jin; Xu, Ji

    2014-10-01

    The fine manipulations of cylindrical vector beams (CVBs) based on metallic microstructures, such as sub-wavelength focusing, have entered many interdisciplinary areas, and the important applications have been found in many fields including optical micromanipulation, super-resolution imaging, micro-machining and so on. But so far, the sub-wavelength focusing of azimuthally polarized beams is encountered, since the manipulation mechanisms rely heavily on the excitation of surface plasmon polaritons, which brings the polarization limitation. We theoretically investigated the focusing behavior of CVBs in 1D metallic photonic crystals (MPCs). The simulation results show that a 1D MPC plano-concave lens can focus cylindrical vector beams into scale of sub-wavelength. The negative refraction at the interface between the air and the 1D MPC is analyzed at the frequencies corresponding to the second photonic band, which makes the 1D MPC has the ability to focus higher Fourier components of light beams. The cylindrical plano-concave structure is constructed to focus the radially and azimuthally polarized beams simultaneously. The behavior is demonstrated by Finite Element Method (FEM). The shape of focusing field can be tailored, by changing the polarization ratio of the incident beams. In addition, the effective sub-wavelength focusing phenomenon can also be realized in variety of wave ranges, by choosing the proper materials and adjusting the parameters. We believe that it's the first time to realize the simultaneous sub-wavelength focusing of radially and azimuthally polarized beams, the application of which is quite promising in broad prospects.

  19. [Research on the temperature field detection method of hot forging based on long-wavelength infrared spectrum].

    PubMed

    Zhang, Yu-Cun; Wei, Bin; Fu, Xian-Bin

    2014-02-01

    A temperature field detection method based on long-wavelength infrared spectrum for hot forging is proposed in the present paper. This method combines primary spectrum pyrometry and three-stage FP-cavity LCTF. By optimizing the solutions of three group nonlinear equations in the mathematical model of temperature detection, the errors are reduced, thus measuring results will be more objective and accurate. Then the system of three-stage FP-cavity LCTF was designed on the principle of crystal birefringence. The system realized rapid selection of any wavelength in a certain wavelength range. It makes the response of the temperature measuring system rapid and accurate. As a result, without the emissivity of hot forging, the method can acquire exact information of temperature field and effectively suppress the background light radiation around the hot forging and ambient light that impact the temperature detection accuracy. Finally, the results of MATLAB showed that the infrared spectroscopy through the three-stage FP-cavity LCTF could meet the requirements of design. And experiments verified the feasibility of temperature measuring method. Compared with traditional single-band thermal infrared imager, the accuracy of measuring result was improved. PMID:24822408

  20. Mid-wavelength infrared heterojunction phototransistors based on type-II InAs/AlSb/GaSb superlattices

    NASA Astrophysics Data System (ADS)

    Haddadi, A.; Adhikary, S.; Dehzangi, A.; Razeghi, M.

    2016-07-01

    A mid-wavelength infrared heterojunction phototransistor based on type-II InAs/AlSb/GaSb superlattices on GaSb substrate has been demonstrated. Near a wavelength of 4 μm saturated optical gains of 668 and 639 at 77 and 150 K, respectively, are demonstrated over a wide dynamic range. At 150 K, the unity optical gain collector dark current density and DC current gain are 1 × 10-3 A/cm2 and 3710, respectively. This demonstrates the potential for use in high-speed applications. In addition, the phototransistor exhibits a specific detectivity value that is four times higher compared with a state-of-the-art type-II superlattice-based photodiode with a similar cut-off wavelength at 150 K.

  1. Wavelength-tunable sources of entangled photons interfaced with atomic vapours

    PubMed Central

    Trotta, Rinaldo; Martín-Sánchez, Javier; Wildmann, Johannes S.; Piredda, Giovanni; Reindl, Marcus; Schimpf, Christian; Zallo, Eugenio; Stroj, Sandra; Edlinger, Johannes; Rastelli, Armando

    2016-01-01

    The prospect of using the quantum nature of light for secure communication keeps spurring the search and investigation of suitable sources of entangled photons. A single semiconductor quantum dot is one of the most attractive, as it can generate indistinguishable entangled photons deterministically and is compatible with current photonic-integration technologies. However, the lack of control over the energy of the entangled photons is hampering the exploitation of dissimilar quantum dots in protocols requiring the teleportation of quantum entanglement over remote locations. Here we introduce quantum dot-based sources of polarization-entangled photons whose energy can be tuned via three-directional strain engineering without degrading the degree of entanglement of the photon pairs. As a test-bench for quantum communication, we interface quantum dots with clouds of atomic vapours, and we demonstrate slow-entangled photons from a single quantum emitter. These results pave the way towards the implementation of hybrid quantum networks where entanglement is distributed among distant parties using optoelectronic devices. PMID:26815609

  2. Wavelength-tunable sources of entangled photons interfaced with atomic vapours

    NASA Astrophysics Data System (ADS)

    Trotta, Rinaldo; Martín-Sánchez, Javier; Wildmann, Johannes S.; Piredda, Giovanni; Reindl, Marcus; Schimpf, Christian; Zallo, Eugenio; Stroj, Sandra; Edlinger, Johannes; Rastelli, Armando

    2016-01-01

    The prospect of using the quantum nature of light for secure communication keeps spurring the search and investigation of suitable sources of entangled photons. A single semiconductor quantum dot is one of the most attractive, as it can generate indistinguishable entangled photons deterministically and is compatible with current photonic-integration technologies. However, the lack of control over the energy of the entangled photons is hampering the exploitation of dissimilar quantum dots in protocols requiring the teleportation of quantum entanglement over remote locations. Here we introduce quantum dot-based sources of polarization-entangled photons whose energy can be tuned via three-directional strain engineering without degrading the degree of entanglement of the photon pairs. As a test-bench for quantum communication, we interface quantum dots with clouds of atomic vapours, and we demonstrate slow-entangled photons from a single quantum emitter. These results pave the way towards the implementation of hybrid quantum networks where entanglement is distributed among distant parties using optoelectronic devices.

  3. Wavelength-tunable sources of entangled photons interfaced with atomic vapours.

    PubMed

    Trotta, Rinaldo; Martín-Sánchez, Javier; Wildmann, Johannes S; Piredda, Giovanni; Reindl, Marcus; Schimpf, Christian; Zallo, Eugenio; Stroj, Sandra; Edlinger, Johannes; Rastelli, Armando

    2016-01-01

    The prospect of using the quantum nature of light for secure communication keeps spurring the search and investigation of suitable sources of entangled photons. A single semiconductor quantum dot is one of the most attractive, as it can generate indistinguishable entangled photons deterministically and is compatible with current photonic-integration technologies. However, the lack of control over the energy of the entangled photons is hampering the exploitation of dissimilar quantum dots in protocols requiring the teleportation of quantum entanglement over remote locations. Here we introduce quantum dot-based sources of polarization-entangled photons whose energy can be tuned via three-directional strain engineering without degrading the degree of entanglement of the photon pairs. As a test-bench for quantum communication, we interface quantum dots with clouds of atomic vapours, and we demonstrate slow-entangled photons from a single quantum emitter. These results pave the way towards the implementation of hybrid quantum networks where entanglement is distributed among distant parties using optoelectronic devices. PMID:26815609

  4. Vertically integrated (Ga, In)N nanostructures for future single photon emitters operating in the telecommunication wavelength range

    NASA Astrophysics Data System (ADS)

    Winden, A.; Mikulics, M.; Grützmacher, D.; Hardtdegen, H.

    2013-10-01

    Important technological steps are discussed and realized for future room-temperature operation of III-nitride single photon emitters. First, the growth technology of positioned single pyramidal InN nanostructures capped by Mg-doped GaN is presented. The optimization of their optical characteristics towards narrowband emission in the telecommunication wavelength range is demonstrated. In addition, a device concept and technology was developed so that the nanostructures became singularly addressable. It was found that the nanopyramids emit in the telecommunication wavelength range if their size is chosen appropriately. A p-GaN contacting layer was successfully produced as a cap to the InN pyramids and the top p-contact was achievable using an intrinsically conductive polymer PEDOT:PSS, allowing a 25% increase in light transmittance compared to standard Ni/Au contact technology. Single nanopyramids were successfully integrated into a high-frequency device layout. These decisive technology steps provide a promising route to electrically driven and room-temperature operating InN based single photon emitters in the telecommunication wavelength range.

  5. [Study on the application for near-infrared spectroscopy quantitative analysis and selecting optimum wavelength by the MAXR regression procedure].

    PubMed

    Zhang, Lu-da; Zhao, Li-li; Zhao, Long-lian; Li, Jun-hui; Yan, Yan-lu

    2005-08-01

    This paper introduces the principle and method with which the model about the quantitative analysis of Fourier transformation near infrared (NIR) spectroscopy by MAXR regression procedure can be established. In this way, the authors have selected the wave length information by Matlab language design programming in order to establish the quantitative analysis models with near infrared spectroscopy. Taking sixty-six wheat samples as experiment materials, quantitative analysis models to determine protein content are established with thirty-three samples. The relative coefficient are 0.977 1 and 0.976 5 respectively and the standard error are 0.335 and 0.340 between the predication result of the two models which include respectively two or three wave length information and Kjeldahl's value for the protein content of the another thirty-three wheat samples. When selecting the wave length information, the MAXR regression procedure can establish the optimum regression models which contain 1 or 2...or k wavelength information respectively. MAXR regression procedure is a useful method when selecting the optimum wavelength information because of its shorter computation time, and the method not only can carefully select the essential wavelength information to establish NIR spectroscopy quantitative analysis models of resisting multicollinearity information disturbance, but also to establish the work for selecting optimum wavelength information which can direct to design the special NIR analysis instrument for analyzing specific component in the special samples. PMID:16329486

  6. Free-standing gold elliptical nanoantenna with tunable wavelength in near-infrared region for enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Shih-Che; Hatab, Nahla A.; Gu, Baohua; Chao, Bo-Kai; Li, Jia-Han; Hsueh, Chun-Hway

    2016-07-01

    The purpose of this work is to present a surface-enhanced Raman scattering (SERS) amplifying antenna for the possible usage in the near-infrared region. Instead of the visible-light range amplifying antenna such as a bowtie, the finite-difference time-domain (FDTD) simulation results indicate that elliptical antenna could provide large electromagnetic field enhancement at near-infrared wavelength by combining the free-standing enhancement property with large aspect ratios of the ellipse geometry. The simulation results consist with the enhancement factors characterized by SERS measurements at the excited wavelength of 785 nm for different aspect ratios and periodicities. In addition to the redshift of the resonance wavelength as the aspect ratio of ellipse increases, the free-standing structure modifies the resonance behavior and the dielectric environment of antenna by elevating the elliptical disk from the substrate. To interpret the simulation results, the analytical solution of resonance wavelength for ellipsoid dimmer is derived based on Lorentz-Mie theory, and comparisons are made between the analytical solution and simulation results. The quasi-static analytical solution provides a way to characterize the resonance behavior of two ellipsoid particles as a function of the gap distance, aspect ratio, and dielectric environment. The electrodynamic analysis for the periodic structure was performed in our FDTD simulations.

  7. Long-Wavelength Stacked SiGe/Si Heterojunction Internal Photoemission Infrared Detectors Using Multiple SiGe/Si Layers

    NASA Technical Reports Server (NTRS)

    Park, J. S.; Lin, T. L.; Jones, E. W.; Castillo, H. M. Del; Gunapala, S. D.

    1994-01-01

    Utilizing low temperature silicon molecular beam epitaxy (MBE) growth, long-wavelength stacked SiGe/Si heterojunction internal photoemission (HIP) infrared detectors with multiple SiGe/Si layers have been fabricated and demonstrated. Using an elemental boron source, high doping concentrations (approximately equal to 4 x 10(sup 20) cm(sup -3)) has been achieved and high crystalline quality multiple Si(sub 0.7)Ge(sub 0.3)/Si layers have been obtained. The detector structure consists of several periods of degenerately boron doped (approximately equal to 4 x 10(sup 20) cm(sup -3)) thin (less than or equal to 50 u Si(sub 0.7)Ge(sub 0.3) layers and undoped thick (approximately equal to 300u Si layers. The multiple p(sup +) - Si(sub 0.7)Ge(sub 0.3)/undoped-Si layers show strong infrared absorption in the long-wavelength regime mainly through free carrier absorption. The stacked Si(sub 0.7)Ge(sub 0.3)/Si HIP detectors with p = 4 x 10(sup 20) cm(sup -3) exhibit strong photoresponse at wavelengths ranging from 2 to 20 (micro)m with quantum efficiencies of about 4% and 1.5% at 10 and 15 (micro)m wavelengths, respectively. The detectors show near ideal thermionic-emission limited dark current characteristics.

  8. Single telecom photon heralding by wavelength multiplexing in an optical fiber

    NASA Astrophysics Data System (ADS)

    Lenhard, Andreas; Brito, José; Kucera, Stephan; Bock, Matthias; Eschner, Jürgen; Becher, Christoph

    2016-01-01

    We demonstrate the multiplexing of a weak coherent and a quantum state of light in a single telecommunication fiber. For this purpose, we make use of spontaneous parametric down conversion and quantum frequency conversion to generate photon pairs at 854 nm and the telecom O-band. The herald photon at 854 nm triggers a telecom C-band laser pulse. The telecom single photon (O-band) and the laser pulse (C-band) are combined and coupled to a standard telecom fiber. Low-background time correlation between the weak coherent and quantum signal behind the fiber shows successful multiplexing.

  9. Proposal of quantitative temperature measurements using two-color technique combined with several infrared radiometers having different detection wavelength bands

    NASA Astrophysics Data System (ADS)

    Inagaki, Terumi; Ishii, Toshimitsu

    2001-03-01

    Infrared thermography has been widely used to visualize a 2D temperature field for various engineering applications. However, in general, conventional infrared thermography cannot directly be applied to quantitative temperature measurement on glossy metal surfaces under near-ambient conditions, because of the severe influence of the reflected energy incident from the surroundings on the measurement. When it is necessary to measure the temperature quantitatively, an appropriate calibration involving complicated procedures must be performed. In this paper, therefore, a new technique of measuring temperature is proposed for near-ambient conditions, by combining simultaneously several infrared radiometers having different detection wavelength bands to enable a two-color technique, which does not require any temperature calibrations. The sensors concerned have a selective wavelength band of several micrometers in width in the range of 2 to 13 micrometers . The applicability of the method, including a series of proposed equations, has been confirmed by an investigation; the numerical simulation presented merely allows a parametric study of how the result varies for different values of emissivity corresponding to a pair of infrared radiometers. An experimental investigation is also performed to estimate or correct the measurement error pertaining to the present technique. This technique has the feature that a 2D temperature field can be evaluated quantitatively, nondestructively, and simultaneously at each picture element without presuming any emissivity and reflectivity, even though the object has a complicated shape; so that it may be useful in various medical or engineering applications.

  10. Development of an interatmospheric window wavelength (5-9 μm) infrared thermography with an advanced image processing technique

    NASA Astrophysics Data System (ADS)

    Sato, Daisuke; Komiyama, Tatsuhito; Sakagami, Takahide; Kubo, Shiro

    2006-04-01

    Recently, deterioration of concrete structures before their design life has become a serious social problem in Japan. Nondestructive inspection techniques are required, for detecting defects and damages in concrete structures, such as subsurface void or delamination. As one of these techniques, the thermographic NDT can be applied as an effective NDT technique to inspect large area of the objective structure from distant place. In addition, it does not require any chemicals and application of physical excitation for inspection. However, the thermographic NDT has a shortcoming that the measurement results are affected by the reflection of atmospheric radiation due to the sunlight, sky or surrounding materials. Since most of the buildings in Japan are covered with luster materials with low emissivity, such as tile or mortal, infrared reflection on the surface is difficult to be neglected. To reduce the influence of these reflection noises, the infrared thermography with detectable wavelength from 5 to 8 μm, which coincides with absorption range of moisture, is utilized. In this research, a new infrared thermography with 5 to 8 μm wavelength range by applying a band pass filter and an uncooled microbolometer infrared array detector. Further, a new signal to noise (S/N) ratio improvement technique has been developed in order to compensate a deterioration of sensitivity due to the band pass filter.

  11. SiGe/Si heterojunction internal photoemission long-wavelength infrared detectors fabricated by molecular beam epitaxy

    NASA Technical Reports Server (NTRS)

    Lin, True-Lon; Ksendzov, A.; Dejewski, Suzan M.; Jones, Eric W.; Fathauer, Robert W.; Krabach, Timothy N.; Maserjian, Joseph

    1991-01-01

    A new SiGe/Si heterojunction internal photoemission (HIP) long-wavelength infrared (LWIR) detector has been fabricated by molecular beam epitaxy (MBE). The detection mechanism of the SiGe/Si HIP detector is infrared absorption in the degenerately doped p+-SiGe layer followed by internal photoemission of photoexcited holes over a heterojunction barrier. By adjusting the Ge concentration in the SiGe layer, and, consequently, the valence band offset between SiGe and Si, the cutoff wavelength of SiGe HIP detectors can be extended into the LWIR (8-17-micron) regime. Detectors were fabricated by growing p+-SiGe layers using MBE on patterned p-type Si substrates. The SiGe layers were boron-doped, with concentrations ranging from 10 to the 19th/cu cm to 4 x 10 to the 20th/cu cm. Infrared absorption of 5-25 percent in a 30-nm-thick p+-SiGe layer was measured in the 3-20-micron range using a Fourier transform infrared spectrometer. Quantum efficiencies of 3-5 percent have been obtained from test devices in the 8-12-micron range.

  12. Two-photon vibrational excitation of air by long-wave infrared laser pulses

    NASA Astrophysics Data System (ADS)

    Palastro, J. P.; Peñano, J.; Johnson, L. A.; Hafizi, B.; Wahlstrand, J. K.; Milchberg, H. M.

    2016-08-01

    Ultrashort long-wave infrared (LWIR) laser pulses can resonantly excite vibrations in N2 and O2 through a two-photon transition. The absorptive vibrational component of the ultrafast optical nonlinearity grows in time, starting smaller than but quickly surpassing the electronic, rotational, and vibrational refractive components. The growth of the vibrational component results in a novel mechanism of third-harmonic generation, providing an additional two-photon excitation channel, fundamental + third harmonic. The original and emergent two-photon excitations drive the resonance exactly out of phase, causing spatial decay of the absorptive vibrational nonlinearity. This nearly eliminates two-photon vibrational absorption. Here we present simulations and analytical calculations demonstrating how these processes modify the ultrafast optical nonlinearity in air. The results reveal nonlinear optical phenomena unique to the LWIR regime of ultrashort pulse propagation in the atmosphere.

  13. Photonically Engineered Incandescent Emitter

    DOEpatents

    Gee, James M.; Lin, Shawn-Yu; Fleming, James G.; Moreno, James B.

    2005-03-22

    A photonically engineered incandescence is disclosed. The emitter materials and photonic crystal structure can be chosen to modify or suppress thermal radiation above a cutoff wavelength, causing the emitter to selectively emit in the visible and near-infrared portions of the spectrum. An efficient incandescent lamp is enabled thereby. A method for fabricating a three-dimensional photonic crystal of a structural material, suitable for the incandescent emitter, is also disclosed.

  14. Photonically engineered incandescent emitter

    DOEpatents

    Gee, James M.; Lin, Shawn-Yu; Fleming, James G.; Moreno, James B.

    2003-08-26

    A photonically engineered incandescence is disclosed. The emitter materials and photonic crystal structure can be chosen to modify or suppress thermal radiation above a cutoff wavelength, causing the emitter to selectively emit in the visible and near-infrared portions of the spectrum. An efficient incandescent lamp is enabled thereby. A method for fabricating a three-dimensional photonic crystal of a structural material, suitable for the incandescent emitter, is also disclosed.

  15. Very high-gain and low-excess noise near-infrared single-photon avalanche detector: an NIR solid state photomultiplier

    NASA Astrophysics Data System (ADS)

    Linga, Krishna; Yevtukhov, Yuriy; Liang, Bing

    2009-05-01

    A new family of photodetectors with a Discrete Amplification (DA) mechanism allows the realization of very high gain and low excess noise factor in the visible and near infrared spectral regions and offers an alternative to conventional photomultiplier tubes and Geiger mode avalanche photodetectors. These photodetectors can operate in linear detection mode with gain-bandwidth product in excess of 4X1014 and in photon counting mode with count rates up to 108 counts/sec. Potential benefits of this technology over conventional avalanche photodetectors include ultra low excess noise factor, very high gain, and lower reset time (<< 1 μs). In the photon counting mode, the devices can be operated in the non-gated mode under a constant dc bias. Because of its unique characteristics of self-quenching and self-recovery, no external quenching circuit is needed. We present the discrete amplification design approach used for the development of a solid state photomultiplier in the near infrared wavelength region. The demonstrated device performance far exceeds any available solid state photodetectors in the near infrared wavelength range. The measured devices have the following performance characteristics: gain > 2X105, excess noise factor < 1.05, rise time < 350ps, fall time < 500ps, dark current < 2X106 cps, operating voltage < 60V. These devices are ideal for researchers in the field of deep space optical communication, spectroscopy, industrial and scientific instrumentation, Ladar/Lidar, quantum cryptography, night vision and other military, defence and aerospace applications.

  16. Wavelength-scanning calibration of detection efficiency of single photon detectors by direct comparison with a photodiode

    NASA Astrophysics Data System (ADS)

    Lee, Hee Jung; Park, Seongchong; Park, Hee Su; Hong, Kee Suk; Lee, Dong-Hoon; Kim, Heonoh; Cha, Myoungsik; Seb Moon, Han

    2016-04-01

    We present a practical calibration method of the detection efficiency (DE) of single photon detectors (SPDs) in a wide wavelength range from 480 nm to 840 nm. The setup consists of a GaN laser diode emitting a broadband luminescence, a tunable bandpass filter, a beam splitter, and a switched integrating amplifier which can measure the photocurrent down to the 100 fA level. The SPD under test with a fibre-coupled beam input is directly compared with a reference photodiode without using any calibrated attenuator. The relative standard uncertainty of the DE of the SPD is evaluated to be from 0.8% to 2.2% varying with wavelength (k  =  1).

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

    PubMed

    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. PMID:26974073

  18. Spectrally-isolated violet to blue wavelength generation by cascaded degenerate four-wave mixing in a photonic crystal fiber.

    PubMed

    Yuan, Jinhui; Kang, Zhe; Li, Feng; Zhang, Xianting; Zhou, Guiyao; Sang, Xinzhu; Wu, Qiang; Yan, Binbin; Zhou, Xian; Wang, Liang; Zhong, Kangping; Wang, Kuiru; Yu, Chongxiu; Tam, Hwa Yaw; Wai, P K A

    2016-06-01

    Generation of spectrally-isolated wavelengths in the violet to blue region based on cascaded degenerate four-wave mixing (FWM) is experimentally demonstrated for the first time in a tailor-made photonic crystal fiber, which has two adjacent zero dispersion wavelengths (ZDWs) at 696 and 852 nm in the fundamental mode. The influences of the wavelength λp and the input average power Pav of the femtosecond pump pulses on the phase-matched frequency conversion process are studied. When femtosecond pump pulses at λp of 880, 870, and 860 nm and Pav of 500 mW are coupled into the normal dispersion region close to the second ZDW, the first anti-Stokes waves generated near the first ZDW act as a secondary pump for the next FWM process. The conversion efficiency ηas2 of the second anti-Stokes waves, which are generated at the violet to blue wavelengths of 430, 456, and 472 nm, are 4.8, 6.48, and 9.66%, for λp equalling 880, 870, and 860 nm, respectively. PMID:27244427

  19. Active wavelength selection for mixture identification with tunable mid-infrared detectors.

    PubMed

    Huang, Jin; Gutierrez-Osuna, Ricardo

    2016-09-21

    This article presents a wavelength selection framework for mixture identification problems. In contrast with multivariate calibration, where the mixture constituents are known and the goal is to estimate their concentration, in mixture identification the goal is to determine which of a large number of chemicals is present. Due to the combinatorial nature of this problem, traditional wavelength selection algorithms are unsuitable because the optimal set of wavelengths is mixture dependent. To address this issue, our framework interleaves wavelength selection with the sensing process, such that each subsequent wavelength is determined on-the-fly based on previous measurements. To avoid early convergence, our approach starts with an exploratory criterion that samples the spectrum broadly, then switches to an exploitative criterion that selects increasingly more relevant wavelengths as the solution approaches the true constituents of the mixture. We compare this "active" wavelength selection algorithm against a state-of-the-art passive algorithm (successive projection algorithm), both experimentally using a tunable spectrometer and in simulation using a large spectral library of chemicals. Our results show that our active method can converge to the true solution more frequently and with fewer measurements than the passive algorithm. The active method also leads to more compact solutions with fewer false positives. PMID:27590540

  20. INFRARED SPECTRUM OF POTASSIUM-CATIONIZED TRIETHYLPHOSPHATE GENERATED USING TANDEM MASS SPECTROMETRY AND INFRARED MULTIPLE PHOTON DISSOCIATION

    SciTech Connect

    Gary S. Groenewold; Christopher M. Leavitt; Ryan P. Dain; Jos Oomens; Jeff Steill; van Stipdonk, Michael J.

    2009-09-01

    Tandem mass spectrometry and wavelength selective infrared photodissociation was used to generate an infrared spectrum of gas-phase triethylphosphate cationized by attachment of K+. Prominent absorptions were observed in the region of 900 to 1300 cm-1 that are characteristic of phosphate P=O and P-O-R stretches. The relative positions and intensities of the IR absorptions were reproduced well by density functional theory (DFT) calculations performed using the B3LYP functional and the 6-31+g(d), 6-311+g(d,p) and 6-311++G(3df,2pd) basis sets. Because of good correspondence between experiment and theory for the cation, DFT was then used to generate a theoretical spectrum for neutral triethylphosphate, which in turn accurately reproduces the IR spectrum of the neat liquid when solvent effects are included in the calculations.

  1. Mercury cadmium telluride short- and medium-wavelength infrared staring focal plane arrays

    NASA Technical Reports Server (NTRS)

    Vural, Kadri

    1987-01-01

    Short and medium IR wavelength 64 x 64 hybrid focal plane arrays (FPAs) have been developed using sapphire-grown HgCdTe. The short wavelength arrays were developed for a prototype airborne imaging spectrometer, while those of medium wavelength are suitable for tactical missile seekers and strategic surveillance systems. Attention is presently given to results obtained for these FPAs' current-voltage characteristics, as well as for their characterization at different temperatures. The detector arrays were also mated to a multiplexer and characterized under different operating conditions. The unit cell size used is 52 x 52 microns.

  2. Mid-infrared silicon-on-sapphire waveguide coupled photonic crystal microcavities

    SciTech Connect

    Zou, Yi E-mail: swapnajit.chakravarty@omegaoptics.com Chen, Ray T. E-mail: swapnajit.chakravarty@omegaoptics.com; Chakravarty, Swapnajit E-mail: swapnajit.chakravarty@omegaoptics.com

    2015-08-24

    We experimentally demonstrate a photonic crystal (PC) microcavity side coupled to a W1.05 photonic crystal waveguide fabricated in silicon-on-sapphire working in mid-IR regime at 3.43 μm. Using a fixed wavelength laser source, propagation characteristics of PC waveguides without microcavity are characterized as a function of lattice constant to determine the light line position, stop gap, and guided mode transmission behavior. The resonance of an L21 PC microcavity coupled to the W1.05 PCW in the guided mode transmission region is then measured by thermal tuning of the cavity resonance across the source wavelength. Resonance quality factor ∼3500 is measured from the temperature dependency curve.

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  4. Infrared (IR) photon-sensitive spectromicroscopy in a cryogenic environment

    DOEpatents

    Pereverzev, Sergey

    2016-06-14

    A system designed to suppress thermal radiation background and to allow IR single-photon sensitive spectromicroscopy of small samples by using both absorption, reflection, and emission/luminescence measurements. The system in one embodiment includes: a light source; a plurality of cold mirrors configured to direct light along a beam path; a cold or warm sample holder in the beam path; windows of sample holder (or whole sample holder) are transparent in a spectral region of interest, so they do not emit thermal radiation in the same spectral region of interest; a cold monochromator or other cold spectral device configured to direct a selected fraction of light onto a cold detector; a system of cold apertures and shields positioned along the beam path to prevent unwanted thermal radiation from arriving at the cold monochromator and/or the detector; a plurality of optical, IR and microwave filters positioned along the beam path and configured to adjust a spectral composition of light incident upon the sample under investigation and/or on the detector; a refrigerator configured to maintain the detector at a temperature below 1.0K; and an enclosure configured to: thermally insulate the light source, the plurality of mirrors, the sample holder, the cold monochromator and the refrigerator.

  5. Photonic approach to the selective inactivation of viruses with a near-infrared ultrashort pulsed laser

    NASA Astrophysics Data System (ADS)

    Tsen, K. T.; Tsen, Shaw-Wei D.; Fu, Q.; Lindsay, S. M.; Kibler, K.; Jacobs, B.; Wu, T. C.; Li, Zhe; Yan, Hao; Cope, Stephanie; Vaiana, Sara; Kiang, Juliann G.

    2010-02-01

    We report a photonic approach for selective inactivation of viruses with a near-infrared ultrashort pulsed (USP) laser. We demonstrate that this method can selectively inactivate viral particles ranging from nonpathogenic viruses such as M13 bacteriophage, tobacco mosaic virus (TMV) to pathogenic viruses like human papillomavirus (HPV) and human immunodeficiency virus (HIV). At the same time sensitive materials like human Jurkat T cells, human red blood cells, and mouse dendritic cells remain unharmed. Our photonic approach could be used for the disinfection of viral pathogens in blood products and for the treatment of blood-borne viral diseases in the clinic.

  6. Novel Ge waveguide platform on Ge-on-insulator wafer for mid-infrared photonic integrated circuits.

    PubMed

    Kang, Jian; Takenaka, Mitsuru; Takagi, Shinichi

    2016-05-30

    We present Ge rib waveguide devices fabricated on a Ge-on-insulator (GeOI) wafer as a proof-of-concept Ge mid-infrared photonics platform. Numerical analysis revealed that the driving current for a given optical attenuation in a carrier-injection Ge waveguide device at a 1.95 μm wavelength can be approximately five times smaller than that in a Si device, enabling in-line carrier-injection Ge optical modulators based on free-carrier absorption. We prepared a GeOI wafer with a 2-μm-thick buried oxide layer (BOX) by wafer bonding. By using the GeOI wafer, we fabricated Ge rib waveguides. The Ge rib waveguides were transparent to 2 μm wavelengths and the propagation loss was found to be 1.4 dB/mm, which may have been caused by sidewall scattering. We achieved a negligible bend loss in the Ge rib waveguide, even with a 5 μm bend radius, owing to the strong optical confinement in the GeOI structure. We also formed a lateral p-i-n junction along the Ge rib waveguide to explore the capability of absorption modulation by carrier injection. By injecting current through the lateral p-i-n junction, we achieved optical intensity modulation in the 2 μm band based on the free-carrier absorption in Ge. PMID:27410108

  7. Large-Format HgCdTe Dual-Band Long-Wavelength Infrared Focal-Plane Arrays

    NASA Astrophysics Data System (ADS)

    Smith, E. P. G.; Venzor, G. M.; Gallagher, A. M.; Reddy, M.; Peterson, J. M.; Lofgreen, D. D.; Randolph, J. E.

    2011-08-01

    Raytheon Vision Systems (RVS) continues to further its capability to deliver state-of-the-art high-performance, large-format, HgCdTe focal-plane arrays (FPAs) for dual-band long-wavelength infrared (L/LWIR) detection. Specific improvements have recently been implemented at RVS in molecular-beam epitaxy (MBE) growth and wafer fabrication and are reported in this paper. The aim of the improvements is to establish producible processes for 512 × 512 30- μm-unit-cell L/LWIR FPAs, which has resulted in: the growth of triple-layer heterojunction (TLHJ) HgCdTe back-to-back photodiode detector designs on 6 cm × 6 cm CdZnTe substrates with 300-K Fourier-transform infrared (FTIR) cutoff wavelength uniformity of ±0.1 μm across the entire wafer; demonstration of detector dark-current performance for the longer-wavelength detector band approaching that of single-color liquid-phase epitaxy (LPE) LWIR detectors; and uniform, high-operability, 512 × 512 30- μm-unit-cell FPA performance in both LWIR bands.

  8. Short-wavelength, mid- and far-infrared intersubband absorption in nonpolar GaN/Al(Ga)N heterostructures

    NASA Astrophysics Data System (ADS)

    Lim, Caroline B.; Beeler, Mark; Ajay, Akhil; Lähnemann, Jonas; Bellet-Amalric, Edith; Bougerol, Catherine; Schörmann, Jörg; Eickhoff, Martin; Monroy, Eva

    2016-05-01

    This paper assesses nonpolar m-oriented GaN:Si/Al(Ga)N heterostructures grown on free-standing GaN for intersubband optoelectronics in the short-wavelength, mid- and far-infrared ranges. Characterization results are compared with reference c-plane samples and interpreted by correlation with self-consistent Schrödinger–Poisson calculations. In the near- and mid-infrared regions, we demonstrate m-GaN/Al(Ga)N multi-quantum-wells exhibiting room-temperature intersubband absorption tunable in the range of 1.5–5.8 µm (827–214 meV), the long wavelength limit being set by the second order of the Reststrahlen band in the GaN substrates. Extending the study to the far-infrared region, low-temperature intersubband transitions in the 1.5–9 THz range (6.3–37.4 meV) are observed in larger m-plane GaN/AlGaN multi-quantum-wells, covering most of the 7–10 THz band forbidden to GaAs-based technologies.

  9. Multi-wavelength injection seeded mid-infrared optical parametric oscillator for DIAL

    SciTech Connect

    Webb, M.S.; Stanion, K.B.; Deane, D.J.

    1996-01-27

    We have constructed and fielded a multi-wavelength injection seeded mid-IR OPO source for DIAL. This OPO system was built for ground based remote sensing measurements of species with both broad (300 cm{sup -1}) and narrow absorption bandwidths (0.07 cm{sup -1} FWHM). The OPO utilizes a single frequency tunable diode laser for the injection seeded signal wavelength in the region from 6400 to 6700 cm{sup -1} and an angle phase-matched 5 cm LiNbO3 crystal to provide large tuning excursions on a slow time scale. The pump was a diode pumped Nd:YAG MOPA (9398 cm{sup -1}) running at 180 Hz. This pump source was repeatedly injection seeded with a different wavelength on each of film sequential shots forming a set of three pulses having wavelength separations on the order of 0.4 cm{sup -1} at a three color set repetition rate of 60 Hz. This combination of OPO signal and pump source produced a set of three time staggered idler wavelengths separated by 0.4 cm{sup -1} with the center wavelength tunable from 2700 to 3000 cm{sup -1}. This OPO system was used in field test experiments to detect the release of chemicals from a standoff distance of 3.3 Km. We present key OPO design criteria, performance data, and numerical simulations that agree with our observations of pump induced spectral impurities in the OPO output.

  10. Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

    NASA Technical Reports Server (NTRS)

    Cook, D. J.; Schlemmer, S.; Balucani, N.; Wagner, D. R.; Harrison, J. A.; Steiner, B.; Saykally, R. J.

    1998-01-01

    Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

  11. Polarization control of an infrared silicon light-emitting diode by dressed photons and analyses of the spatial distribution of doped boron atoms

    NASA Astrophysics Data System (ADS)

    Kawazoe, Tadashi; Nishioka, Katsuhiro; Ohtsu, Motoichi

    2015-12-01

    This paper reports the fabrication of a polarization-controlled infrared LED fabricated by dressed-photon-phonon (DPP)-assisted annealing of a bulk Si crystal. For the DPP-assisted annealing, linearly polarized infrared light with a wavelength of 1.342 μm was made normally incident on the top surface of the crystal. The photon energy at the peak of the emitted light spectrum of the fabricated LED was close to that of the light irradiated during the DPP-assisted annealing. A degree of polarization of as large as 0.07 was obtained. The spatial distribution of the doped B atoms in the fabricated LED was measured, and the following findings were obtained: (1) B atoms formed pairs in which the separation between the two B atoms was three times the lattice constant of the Si crystal; and (2) the B atom pairs were apt to orient along the direction perpendicular to the propagation direction and to the polarization direction of the light irradiated during the DPP-assisted annealing. Based on these findings (1) and (2), photon breeding was confirmed with respect to photon energy and spin, respectively.

  12. A new design methodology of obtaining wide band high gain broadband parametric source for infrared wavelength applications

    NASA Astrophysics Data System (ADS)

    Maji, Partha Sona; Roy Chaudhuri, Partha

    2016-03-01

    In this article, we have presented a new design methodology of obtaining wide band parametric sources based on highly nonlinear chalcogenide material of As2S3. The dispersion profile of the photonic crystal fiber (PCF) has been engineered wisely by reducing the diameter of the second air-hole ring to have a favorable higher order dispersion parameter. The parametric gain dependence upon fiber length, pump power, and different pumping wavelengths has been investigated in detail. Based upon the nonlinear four wave mixing phenomenon, we are able to achieve a wideband parametric amplifier with peak gain of 29 dB with FWHM of ≈2000 nm around the IR wavelength by proper tailoring of the dispersion profile of the PCF with a continuous wave Erbium (Er3+)-doped ZBLAN fiber laser emitting at 2.8 μm as the pump source with an average power of 5 W. The new design methodology will unleash a new dimension to the chalcogenide material based investigation for wavelength translation around IR wavelength band.

  13. Photon bunching and the photon-noise-limited performance of infrared detectors

    NASA Technical Reports Server (NTRS)

    Boyd, R. W.

    1982-01-01

    The photon-noise-limited performance of a radiation detector exposed to a thermal background of temperature T is analyzed by calculating the resulting specific detectivity. Both ideal photon detectors of arbitrary quantum efficiency eta and ideal thermal detectors of arbitrary emissivity eta are considered; and the effects of both shot noise and excess noise are taken into account. The relative contributions of these two sources depend on the quantum efficiency or emissivity of the system. For frequencies nu such that hnu/kT is much less than eta, excess noise can make an appreciable contribution to the total system noise. For the case of the detection of the narrow-band radiation, the specific detectivity is independent of eta in the limit hnu/kT is much less than eta.

  14. Wavelength dependence of photon-induced photoacoustic streaming technique for root canal irrigation

    NASA Astrophysics Data System (ADS)

    Lukač, Nejc; Zadravec, Jure; Gregorčič, Peter; Lukač, Matjaž; Jezeršek, Matija

    2016-07-01

    Laser-enhanced irrigation of complex root canals appears to be a very promising technique to improve the outcome of root canal treatment. This applies, in particular, if the technique can be effective at very low laser energies in irrigating not only the main canal but also the small lateral canals. This is important in order to avoid potential undesirable effects at higher laser energies such as temperature increase, dentin ablation, or extrusion of irrigating solution beyond the apical foramen. An improved understanding of the role of laser parameters, such as laser wavelength and pulse duration, in irrigation of lateral canals is therefore desired in order to optimize treatment efficacy. The influence of laser wavelength and pulse duration on cavitation phenomena was studied using shadow photography and a method of measuring fluid flow in lateral canals based on tracking of movements of small air bubbles naturally forming in liquid as a result of laser agitation. A simulated model of a root canal including a narrow lateral canal designed to represent typical root canal morphology was used for the water flow measurements. The following three laser wavelengths with relatively high absorption in water were studied: Er:YAG (2.94 μm), Er,Cr:YSGG (2.73 μm), and Nd:YAP (1.34 μm). Among the three wavelengths studied, the Er:YAG laser wavelength was found to be the most effective in formation of cavitation bubbles and in generating fluid motions within narrow lateral canals. A comparison between the shadow photography and fluid motion data indicates that it is the bubble's radius and not the bubble's volume that predominantly influences the fluid motion within lateral canals. Based on the results of our study, it appears that effective minimally invasive laser-assisted irrigation can be performed with low Er:YAG laser pulse energies below 10 mJ.

  15. Development of Short Wavelength Infrared Array Detectors for Space Astronomy Application

    NASA Technical Reports Server (NTRS)

    Fazio, Giovanni G.

    1997-01-01

    The Smithsonian Astrophysical Observatory (SAO) and its team - the University of Arizona (UA), the University of Rochester (UR), Santa Barbara Research Center (SBRC), Ames Research Center (ARC), and Goddard Space Flight Center (GSFC) - are carrying out a research program with the goal of developing and optimizing infrared arrays in the 2-27 micron range for space infrared astronomy. This report summarizes research results for the entire grant period 1 January 1992 through 30 June 1996.

  16. Coaxial Dual-wavelength Interferometric Method for a Thermal Infrared Focal-plane-array with Integrated Gratings.

    PubMed

    Shang, Yuanfang; Ye, Xiongying; Cao, Liangcai; Song, Pengfei; Feng, Jinyang

    2016-01-01

    Uncooled infrared (IR) focal-plane-array (FPA) with both large sensing range and high sensitivity is a great challenge due to the limited dynamic range of the detected signals. A coaxial dual-wavelength interferometric system was proposed here to detect thermal-induced displacements of an ultrasensitive FPA based on polyvinyl-chloride(PVC)/gold bimorph cantilevers and carbon nanotube (CNT)-based IR absorbing films. By alternately selecting the two displacement measurements performed by λ1 (=640 nm) and λ2 (=660 nm), the temperature measuring range with greater than 50% maximum sensitivity can be extended by eight-fold in comparison with the traditional single-wavelength mode. Meanwhile, the relative measurement error over the full measuring range is below 0.4%. In addition, it offers a feasible approach for on-line and on-wafer FPA characterization with great convenience and high efficiency. PMID:27193803

  17. Coaxial Dual-wavelength Interferometric Method for a Thermal Infrared Focal-plane-array with Integrated Gratings

    NASA Astrophysics Data System (ADS)

    Shang, Yuanfang; Ye, Xiongying; Cao, Liangcai; Song, Pengfei; Feng, Jinyang

    2016-05-01

    Uncooled infrared (IR) focal-plane-array (FPA) with both large sensing range and high sensitivity is a great challenge due to the limited dynamic range of the detected signals. A coaxial dual-wavelength interferometric system was proposed here to detect thermal-induced displacements of an ultrasensitive FPA based on polyvinyl-chloride(PVC)/gold bimorph cantilevers and carbon nanotube (CNT)-based IR absorbing films. By alternately selecting the two displacement measurements performed by λ1 (=640 nm) and λ2 (=660 nm), the temperature measuring range with greater than 50% maximum sensitivity can be extended by eight-fold in comparison with the traditional single-wavelength mode. Meanwhile, the relative measurement error over the full measuring range is below 0.4%. In addition, it offers a feasible approach for on-line and on-wafer FPA characterization with great convenience and high efficiency.

  18. Coaxial Dual-wavelength Interferometric Method for a Thermal Infrared Focal-plane-array with Integrated Gratings

    PubMed Central

    Shang, Yuanfang; Ye, Xiongying; Cao, Liangcai; Song, Pengfei; Feng, Jinyang

    2016-01-01

    Uncooled infrared (IR) focal-plane-array (FPA) with both large sensing range and high sensitivity is a great challenge due to the limited dynamic range of the detected signals. A coaxial dual-wavelength interferometric system was proposed here to detect thermal-induced displacements of an ultrasensitive FPA based on polyvinyl-chloride(PVC)/gold bimorph cantilevers and carbon nanotube (CNT)-based IR absorbing films. By alternately selecting the two displacement measurements performed by λ1 (=640 nm) and λ2 (=660 nm), the temperature measuring range with greater than 50% maximum sensitivity can be extended by eight-fold in comparison with the traditional single-wavelength mode. Meanwhile, the relative measurement error over the full measuring range is below 0.4%. In addition, it offers a feasible approach for on-line and on-wafer FPA characterization with great convenience and high efficiency. PMID:27193803

  19. Aircraft engine-mounted camera system for long wavelength infrared imaging of in-service thermal barrier coated turbine blades.

    PubMed

    Markham, James; Cosgrove, Joseph; Scire, James; Haldeman, Charles; Agoos, Ian

    2014-12-01

    This paper announces the implementation of a long wavelength infrared camera to obtain high-speed thermal images of an aircraft engine's in-service thermal barrier coated turbine blades. Long wavelength thermal images were captured of first-stage blades. The achieved temporal and spatial resolutions allowed for the identification of cooling-hole locations. The software and synchronization components of the system allowed for the selection of any blade on the turbine wheel, with tuning capability to image from leading edge to trailing edge. Its first application delivered calibrated thermal images as a function of turbine rotational speed at both steady state conditions and during engine transients. In advance of presenting these data for the purpose of understanding engine operation, this paper focuses on the components of the system, verification of high-speed synchronized operation, and the integration of the system with the commercial jet engine test bed. PMID:25554314

  20. Aircraft engine-mounted camera system for long wavelength infrared imaging of in-service thermal barrier coated turbine blades

    NASA Astrophysics Data System (ADS)

    Markham, James; Cosgrove, Joseph; Scire, James; Haldeman, Charles; Agoos, Ian

    2014-12-01

    This paper announces the implementation of a long wavelength infrared camera to obtain high-speed thermal images of an aircraft engine's in-service thermal barrier coated turbine blades. Long wavelength thermal images were captured of first-stage blades. The achieved temporal and spatial resolutions allowed for the identification of cooling-hole locations. The software and synchronization components of the system allowed for the selection of any blade on the turbine wheel, with tuning capability to image from leading edge to trailing edge. Its first application delivered calibrated thermal images as a function of turbine rotational speed at both steady state conditions and during engine transients. In advance of presenting these data for the purpose of understanding engine operation, this paper focuses on the components of the system, verification of high-speed synchronized operation, and the integration of the system with the commercial jet engine test bed.

  1. A calibrated dual-wavelength infrared thermometry approach with non-greybody compensation for machining temperature measurements

    NASA Astrophysics Data System (ADS)

    Hijazi, A.; Sachidanandan, S.; Singh, R.; Madhavan, V.

    2011-02-01

    We report the development of a new approach for determining temperatures using the dual-wavelength infrared thermometry technique, which does not presume greybody behaviour and compensates for the spectral dependence of emissivity. This approach is based on Planck's radiation equation and explicitly accounts for the wavelength-dependent response of the IR detector and the losses occurring due to each of the elements of the IR imaging system that affect the total radiant energy sensed in different spectral bands. A thorough calibration procedure is utilized to determine a compensation factor for the spectral dependence of emissivity, which is referred to as the non-greybody compensation factor (NGCF). Calibration and validation experiments are carried out on Aluminum 6061-T6 targets with two different surface roughnesses. Results show that this alloy does not exhibit greybody behaviour, even though the two spectral bands used were relatively close to each other, and that the spectral dependence of emissivity is influenced by the surface finish. It is found that non-greybody behaviour of low emissivity surfaces can lead to significant systematic error in dual-wavelength IR thermometry. The inclusion of the NGCF eliminates the systematic error caused by the invalidity of greybody assumption and thus improves the accuracy of the measurements. Non-greybody-compensated dual-wavelength thermography is used to measure the chip temperature along the tool-chip interface during orthogonal cutting of Al 6061-T6 and sample results at three different cutting speeds are presented.

  2. Determination of the wavelength dependence of the differential pathlength factor from near-infrared pulse signals.

    PubMed

    Kohl, M; Nolte, C; Heekeren, H R; Horst, S; Scholz, U; Obrig, H; Villringer, A

    1998-06-01

    For the calculation of changes in oxyhaemoglobin, deoxyhaemoglobin and the redox state of cytochrome-c-oxidase from attenuation data via a modified Beer-Lambert equation the wavelength dependence of the differential pathlength factor (DPF(lambda)) has to be taken into account. The DPF, i.e. the ratio of the mean optical pathlength and the physical light source-detector separation at each wavelength, determines the crosstalk between the different concentrations and is therefore essential for a sensitive detection of chromophore changes. Here a simple method is suggested to estimate the wavelength dependence of the DPF(lambda) from pulse-induced attenuation changes measured on the head of adult humans. The essence is that the DPF is the ratio of the attenuation changes over absorption coefficient changes, and that the spectral form of the pulse correlated absorption coefficient change can be assumed to be proportional to the extinction coefficient of blood. Indicators for the validity of the DPF(lambda) derived for wavelengths between 700 and 970 nm are the stability of the calculated haemoglobin and cytochrome signals with variations of the wavelength range included for their calculation and its overall agreement with the data available from the literature. PMID:9651039

  3. Wavelength-selected photon-number-splitting attack against plug-and-play quantum key distribution systems with decoy states

    NASA Astrophysics Data System (ADS)

    Jiang, Mu-Sheng; Sun, Shi-Hai; Li, Chun-Yan; Liang, Lin-Mei

    2012-09-01

    Any imperfections in a practical quantum key distribution (QKD) system may be exploited by an eavesdropper (Eve) to collect information about the key without being discovered. For example, without the decoy-state method, Eve can perform the photon-number-splitting (PNS) attack and get full information without introducing any perturbation, since weak laser pulses are widely used in practical systems instead of single-photon sources. However, the decoy-state method against PNS attack itself may introduce another loophole while closing the loophole of multiphoton pulses. In this paper, a fatal loophole of practical decoy-state plug-and-play QKD systems has been exploited and a wavelength-selected photon-number-splitting (WSPNS) attack scheme against plug-and-play QKD systems with the decoy-state method is proposed. Theoretical analysis shows that the eavesdropper can get full information about the key generated between the legitimate parties just like the PNS attack was performed in plug-and-play QKD systems without the decoy-state method.

  4. Generation of stable and narrow spacing dual-wavelength ytterbium-doped fiber laser using a photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Ahmad, Harith; Aizi Mat Salim, Muhammad; Soltanian, Mohammad Reza K.; Razalli Azzuhri, Saaidal; Wadi Harun, Sulaiman; Yasin, Moh.

    2016-05-01

    We demonstrate the design and operation of novel narrow spacing and stable dual-wavelength fiber laser (DWFL). A 70-cm ytterbium-doped fiber has been chosen as the gain medium in a ring cavity arrangement. Our design includes a short length photonic crystal fiber, acting as a dual-wavelength stabilizer based on its birefringence coefficient and nonlinear behavior and tunable band pass filter (TBPF) to achieve narrow spacing spectrum lasing. Our laser output is considered to be highly stable, with power fluctuation less than 0.8 dB over a period of 15 min. The flexibility and tunability of TBPF, together with polarization controller enable the spacing tuning of the DWFL from 0.03 nm up to 0.07 nm for 1040 nm region, and 0.10 nm up to 0.40 nm for 1060 nm region. The tunable wavelength spacing shows the flexibility of the DWFL in addition to stable and reliable properties of fiber laser in 1-μm region.

  5. Optical Properties of Iron Silicates in the Infrared to Millimeter as a Function of Wavelength and Temperature

    NASA Technical Reports Server (NTRS)

    Richey, C. R.; Kinzer, R. E.; Cataldo, G.; Wollack, E. J.; Nuth, J. A.; Benford, D. J.; Silverberg, R. F.; Rinehart, S. A.

    2013-01-01

    The Optical Properties of Astronomical Silicates with Infrared Techniques (OPASI-T) program utilizes multiple instruments to provide spectral data over a wide range of temperature and wavelengths. Experimental methods include Vector Network Analyzer (VNA) and Fourier Transform Spectroscopy (FTS) transmission, and reflection/scattering measurements. From this data, we can determine the optical parameters for the index of refraction, n, and the absorption coefficient, k. The analysis of the laboratory transmittance data for each sample type is based upon different mathematical models, which are applied to each data set according to their degree of coherence. Presented here are results from iron silicate dust grain analogs, in several sample preparations and at temperatures ranging from 5-300 K, across the infrared and millimeter portion of the spectrum (from 2.5-10,000 m or 4,000-1 cm(exp-1).

  6. Optical Properties of Iron Silicates in the Infrared to Millimeter as a Function of Wavelength and Temperature

    NASA Technical Reports Server (NTRS)

    Richey, Christina Rae; Kinzer, R. E.; Cataldo, R. E. G.; Wollack, E. J.; Nuth, J. A.; Benford, D. J.; Silverberg, R. F.; Rinehart, S. A.

    2013-01-01

    The Optical Properties of Astronomical Silicates with Infrared Techniques (OPASI-T) program utilizes multiple instruments to provide spectral data over a wide range of temperature and wavelengths. Experimental methods include Vector Network Analyzer (VNA) and Fourier Transform Spectroscopy (FTS) transmission, and reflection/scattering measurements. From this data, we can determine the optical parameters for the index of refraction, n, and the absorption coefficient, k. The analysis of the laboratory transmittance data for each sample type is based upon different mathematical models, which are applied to each data set according to their degree of coherence. Presented here are results from iron silicate dust grain analogs, in several sample preparations and at temperatures ranging from 5-300 K, across the infrared and millimeter portion of the spectrum (from 2.5-10,000 µm or 4,000-1 cm(exp -1).

  7. Optical Properties of Iron Silicates in the Infrared to Millimeter as a Function of Wavelength and Temperature

    NASA Technical Reports Server (NTRS)

    Richey, C. R.; Kinzer, R. E.; Cataldo, G.; Wollack, E. J.; Nuth, J. A.; Benford, D. J.; Silverberg, R. F.; Rinhart, S. A.

    2013-01-01

    The Optical Properties of Astronomical Silicates with Infrared Techniques program utilizes multiple instruments to provide spectral data over a wide range of temperatures and wavelengths. Experimental methods include Vector Network Analyzer and Fourier transform spectroscopy transmission, and reflection/scattering measurements. From this data, we can determine the optical parameters for the index of refraction, n, and the absorption coefficient, k. The analysis of the laboratory transmittance data for each sample type is based upon different mathematical models, which are applied to each data set according to their degree of coherence. Presented here are results from iron silicate dust grain analogs, in several sample preparations and at temperatures ranging from 5 to 300 K, across the infrared and millimeter portion of the spectrum (from 2.5 to 10,000/micron or 4000 to 1/cm).

  8. A PRELIMINARY CALIBRATION OF THE RR LYRAE PERIOD-LUMINOSITY RELATION AT MID-INFRARED WAVELENGTHS: WISE DATA

    SciTech Connect

    Madore, Barry F.; Freedman, Wendy L.; Kollmeier, Juna A.; Monson, Andy; Eric Persson, S.; Rich, Jeff A. Jr.; Scowcroft, Victoria; Seibert, Mark; Hoffman, Douglas E-mail: wendy@obs.carnegiescience.edu E-mail: amonson@obs.carnegiescience.edu E-mail: jrich@obs.carnegiescience.edu E-mail: mseibert@obs.carnegiescience.edu

    2013-10-20

    Using time-resolved, mid-infrared data from the Wide-field Infrared Survey Explorer (WISE) and geometric parallaxes from the Hubble Space Telescope for four Galactic RR Lyrae variables, we derive the following Population II period-luminosity (PL) relations for the WISE [W1], [W2], and [W3] bands at 3.4, 4.6, and 12 μm, respectively: The slopes and the scatter around the fits are consistent with a smooth extrapolation of those same quantities from previously published K-band observations at 2.2 μm, where the asymptotic (long-wavelength) behavior is consistent with a period-radius relation with a slope of 0.5. No obvious correlation with metallicity (spanning 0.4 dex in [Fe/H]) is found in the residuals of the four calibrating RR Lyrae stars about the mean PL regression line.

  9. Coupling mid-infrared light from a photonic crystal waveguide to metallic transmission lines

    SciTech Connect

    Blanco-Redondo, Andrea E-mail: r.hillenbrand@nanogune.eu; Garcia-Adeva, Angel; Zubia, Joseba

    2014-01-06

    We propose and theoretically study a hybrid structure consisting of a photonic crystal waveguide (PhC-wg) and a two-wire metallic transmission line (TL), engineered for efficient transfer of mid-infrared (mid-IR) light between them. An efficiency of 32% is obtained for the coupling from the transverse magnetic (TM) photonic mode to the symmetric mode of the TL, with a predicted intensity enhancement factor of 53 at the transmission line surface. The strong coupling is explained by the small phase velocity mismatch and sufficient spatial overlapping between the modes. This hybrid structure could find applications in highly integrated mid-IR photonic-plasmonic devices for biological and gas sensing, among others.

  10. 640x486 Long-wavelength Dualband GaAs/AlGaAs Quantum Well Infrared Photodetector (QWIP) Focal Plane Array Camera

    NASA Technical Reports Server (NTRS)

    Gunapala, S.; Bandara, S.; Liu, J.; Rafol, S.; Luong, E.; Mumolo, J.; Tran, N.

    1999-01-01

    An optimized long-wavelength/very long-wavelength two-color Quantum Well Infrared Photodetector (QWIP) device structure has been designed. This device structure was grown on a three-inch semi-insulating GaAs substrate by molecular beam epitaxy (MBE).

  11. Strong transmittance above the light line in mid-infrared two-dimensional photonic crystals

    SciTech Connect

    Kraeh, Christian; Martinez-Hurtado, J. L.; Zeitlmair, Martin; Finley, Jonathan J.; Popescu, Alexandru; Hedler, Harry

    2015-06-14

    The mid-infrared region of the electromagnetic spectrum between 3 and 8 μm hosts absorption lines of gases relevant for chemical and biological sensing. 2D photonic crystal structures capable of guiding light in this region of the spectrum have been widely studied, and their implementation into miniaturized sensors has been proposed. However, light guiding in conventional 2D photonic crystals is usually restricted to a frequency range below the light line, which is the dispersion relation of light in the media surrounding the structures. These structures rely on total internal reflection for confinement of the light in z-direction normal to the lattice plane. In this work, 2D mid-infrared photonic crystals consisting of microtube arrays that mitigate these limitations have been developed. Due to their high aspect ratios of ∼1:30, they are perceived as semi-infinite in the z-direction. Light transmission experiments in the 5–8 μm range reveal attenuations as low as 0.27 dB/100 μm, surpassing the limitations for light guiding above the light line in conventional 2D photonic crystals. Fair agreement is obtained between these experiments, 2D band structure and transmission simulations.

  12. Strong transmittance above the light line in mid-infrared two-dimensional photonic crystals

    NASA Astrophysics Data System (ADS)

    Kraeh, Christian; Martinez-Hurtado, J. L.; Zeitlmair, Martin; Popescu, Alexandru; Hedler, Harry; Finley, Jonathan J.

    2015-06-01

    The mid-infrared region of the electromagnetic spectrum between 3 and 8 μm hosts absorption lines of gases relevant for chemical and biological sensing. 2D photonic crystal structures capable of guiding light in this region of the spectrum have been widely studied, and their implementation into miniaturized sensors has been proposed. However, light guiding in conventional 2D photonic crystals is usually restricted to a frequency range below the light line, which is the dispersion relation of light in the media surrounding the structures. These structures rely on total internal reflection for confinement of the light in z-direction normal to the lattice plane. In this work, 2D mid-infrared photonic crystals consisting of microtube arrays that mitigate these limitations have been developed. Due to their high aspect ratios of ˜1:30, they are perceived as semi-infinite in the z-direction. Light transmission experiments in the 5-8 μm range reveal attenuations as low as 0.27 dB/100 μm, surpassing the limitations for light guiding above the light line in conventional 2D photonic crystals. Fair agreement is obtained between these experiments, 2D band structure and transmission simulations.

  13. Turbid water measurements of remote sensing penetration depth at visible and near-infrared wavelength

    NASA Technical Reports Server (NTRS)

    Morris, W. D.; Witte, W. G.; Whitlock, C. H.

    1980-01-01

    Remote sensing of water quality is dicussed. Remote sensing penetration depth is a function both of water type and wavelength. Results of three tests to help demonstrate the magnitude of this dependence are presented. The water depth to which the remote-sensor data was valid was always less than that of the Secchi disk depth, although not always the same fraction of that depth. The penetration depths were wavelength dependent and showed the greatest variation for the water type with largest Secchi depth. The presence of a reflective plate, simulating a reflective subsurface, increased the apparent depth of light penetration from that calculated for water of infinite depth.

  14. Three-photon near-infrared quantum cutting in Tm{sup 3+}-doped transparent oxyfluoride glass ceramics

    SciTech Connect

    Yu, D. C.; Zhang, J. P.; Chen, Q. J.; Zhang, W. J.; Yang, Z. M.; Zhang, Q. Y.

    2012-10-22

    Efficient three-step sequential three-photon near-infrared (NIR) quantum cutting in Tm{sup 3+}-doped transparent oxyfluoride glass ceramics has been demonstrated, where an absorbed blue photon could be cut into three NIR photons at 1190, 1460, and 1800 nm with quantum yield greater than unity. On the basis of static and dynamic photoemission, monitored excitation, and time-resolved fluorescence spectra, we investigate in detail the underlying optoelectronic mechanism. Further development of an efficient triply-cutting material might open up a path towards ultra-efficient photonic devices, which enables more photons emitted than absorbed in the excitation process.

  15. Differentiation of Rubidiated Methyl-d-Glycoside Stereoisomers by Infrared Multiple-Photon Dissociation Spectroscopy in the O-H and C-H Stretching Regions.

    PubMed

    Pearson, Wright L; Contreras, Cesar; Powell, David; Berden, Giel; Oomens, Jos; Bendiak, Brad; Eyler, John R

    2015-10-15

    Four isomeric sugar methylglycosides (α- and β-d-gluco- and galactopyranosides) were evaluated as rubidium cation coordination adducts in the gas phase using variable-wavelength multiple-photon dissociation in the range from 2750 to 3750 cm(-1). The adducts dissociated following photon absorption to yield neutral sugars and the rubidium cation, resulting in infrared "action" spectra. Well-resolved hydroxyl stretching bands clearly differentiate stereoisomers that vary solely in their asymmetry at single carbons. Density functional theory calculations of the lowest-energy gas-phase complexes indicate that rubidium coordinates with lone pairs of oxygen atoms as either bi- or tridentate complexes and that more than one positional coordination isomer could adequately account for most of the O-H stretch frequencies observed for each methylglycoside. PMID:26393375

  16. Photocurrent spectrum study of a quantum dot single-photon detector based on resonant tunneling effect with near-infrared response

    SciTech Connect

    Weng, Q. C.; An, Z. H. E-mail: luwei@mail.sitp.ac.cn; Xiong, D. Y.; Zhu, Z. Q.; Zhang, B.; Chen, P. P.; Li, T. X.; Lu, W. E-mail: luwei@mail.sitp.ac.cn

    2014-07-21

    We present the photocurrent spectrum study of a quantum dot (QD) single-photon detector using a reset technique which eliminates the QD's “memory effect.” By applying a proper reset frequency and keeping the detector in linear-response region, the detector's responses to different monochromatic light are resolved which reflects different detection efficiencies. We find the reset photocurrent tails up to 1.3 μm wavelength and near-infrared (∼1100 nm) single-photon sensitivity is demonstrated due to interband transition of electrons in QDs, indicating the device a promising candidate both in quantum information applications and highly sensitive imaging applications operating in relative high temperatures (>80 K).

  17. Some observations on hyperuniform disordered photonic bandgap materials, from microwave scale study to infrared scale study

    NASA Astrophysics Data System (ADS)

    Tsitrin, Sam; Nahal, Geev; Florescu, Marian; Man, Weining; San Francisco State University Team; University of Surrey Team

    2015-03-01

    A novel class of disordered photonic materials, hyperuniform disordered solids (HUDS), attracted more attention. Recently they have been experimentally proven to provide complete photonic band gap (PBG) when made with Alumina or Si; as well as single-polarization PBG when made with plastic with refract index of 1.6. These PBGs were shown to be real energy gaps with zero density of photonic states, instead of mobility gaps of low transmission due to scattering, etc. Using cm-scale samples and microwave experiments, we reveal the nature of photonic modes existing in these disordered materials by analyzing phase delay and mapping field distribution profile inside them. We also show how to extend the proof-of-concept microwave studies of these materials to proof-of-scale studies for real applications, by designing and fabricating these disordered photonic materials at submicron-scale with functional devices for 1.55 micron wavelength. The intrinsic isotropy of the disordered structure is an inherent advantage associated with the absence of limitations of orientational order, which is shown to provide valuable freedom in defect architecture design impossible in periodical structures. NSF Award DMR-1308084, the University of Surrey's FRSF and Santander awards.

  18. Determination of the wavelength dependence of the differential pathlength factor from near-infrared pulse signals

    NASA Astrophysics Data System (ADS)

    Kohl, Matthias; Nolte, Christian; Heekeren, Hauke R.; Horst, Susanne; Scholz, Udo; Obrig, Hellmuth; Villringer, Arno

    1998-06-01

    For the calculation of changes in oxyhaemoglobin, deoxyhaemoglobin and the redox state of cytochrome-c-oxidase from attenuation data via a modified Beer-Lambert equation the wavelength dependence of the differential pathlength factor (DPF) has to be taken into account. The DPF, i.e. the ratio of the mean optical pathlength and the physical light source-detector separation at each wavelength, determines the crosstalk between the different concentrations and is therefore essential for a sensitive detection of chromophore changes. Here a simple method is suggested to estimate the wavelength dependence of the DPF from pulse-induced attenuation changes measured on the head of adult humans. The essence is that the DPF is the ratio of the attenuation changes over absorption coefficient changes, and that the spectral form of the pulse correlated absorption coefficient change can be assumed to be proportional to the extinction coefficient of blood. Indicators for the validity of the DPF derived for wavelengths between 700 and 970 nm are the stability of the calculated haemoglobin and cytochrome signals with variations of the wavelength range included for their calculation and its overall agreement with the data available from the literature.

  19. [Study on the application of ridge regression to near-infrared spectroscopy quantitative analysis and optimum wavelength selection].

    PubMed

    Zhang, Man; Liu, Xu-Hua; He, Xiong-Kui; Zhang, Lu-Da; Zhao, Long-Lian; Li, Jun-Hui

    2010-05-01

    In the present paper, taking 66 wheat samples for testing materials, ridge regression technology in near-infrared (NIR) spectroscopy quantitative analysis was researched. The NIR-ridge regression model for determination of protein content was established by NIR spectral data of 44 wheat samples to predict the protein content of the other 22 samples. The average relative error was 0.015 18 between the predictive results and Kjeldahl's values (chemical analysis values). And the predictive results were compared with those values derived through partial least squares (PLS) method, showing that ridge regression method was deserved to be chosen for NIR spectroscopy quantitative analysis. Furthermore, in order to reduce the disturbance to predictive capacity of the quantitative analysis model resulting from irrelevant information, one effective way is to screen the wavelength information. In order to select the spectral information with more content information and stronger relativity with the composition or the nature of the samples to improve the model's predictive accuracy, ridge regression was used to select wavelength information in this paper. The NIR-ridge regression model was established with the spectral information at 4 wavelength points, which were selected from 1 297 wavelength points, to predict the protein content of the 22 samples. The average relative error was 0.013 7 and the correlation coefficient reached 0.981 7 between the predictive results and Kjeldahl's values. The results showed that ridge regression was able to screen the essential wavelength information from a large amount of spectral information. It not only can simplify the model and effectively reduce the disturbance resulting from collinearity information, but also has practical significance for designing special NIR analysis instrument for analyzing specific component in some special samples. PMID:20672604

  20. Dense wavelength division multiplexing photonic transport for radio frequency and microwave wireless services

    NASA Astrophysics Data System (ADS)

    Paolella, Arthur C.; Jemison, William D.; Borlando, Javier; Wang, Jun

    2004-10-01

    The expected increase in space and terrestrial services that include two-way fixed, SATCOM, CATV and mobile wireless services require expanding the system capacity. This expansion has created an opportunity for the utilization of the demonstrated photonic transport systems in wireless networks. System demonstrations and architectural developments have been proposed for distribution of communication services over fiber. Termed Fiber Radio and Hybrid Fiber Wireless, these systems offer the potential to improve services and reduce base station costs through increased bandwidth and ease of installation. We have developed and demonstrated DWDM broadband photonic transport systems able to meet the requirements for IS-95 Personal Communications Services operating at 1.9 GHz and Broadband Wireless Internet operating over the band of 2.5 to 2.7 GHz. Each DWDM channel operates from 1 to 3 GHz transporting services up to 80 Km. Solutions are being sought for low cost transmitters to meet DWDM SATCOM system requirements include extending the transmission distance to over 100 Km with a bandwidth that exceeds multiple octaves. These new requirements put high performance demands on the optical components. We have developed high performance transmitters based on electro-absorption modulated lasers (EML) that can meet SATCOM requirements. We have shown that the EML is capable of providing the required CNR of 32 dB for satellite transmission in the band of 950 to 2150 MHz over a 100 Km distance. In addition, we are investigating a new modulation technique, Microwave Photonic Vector Modulation (MPVM), which has the potential for wideband transmission in DWDM systems.

  1. Controllable spiking patterns in long-wavelength vertical cavity surface emitting lasers for neuromorphic photonics systems

    SciTech Connect

    Hurtado, Antonio; Javaloyes, Julien

    2015-12-14

    Multiple controllable spiking patterns are achieved in a 1310 nm Vertical-Cavity Surface Emitting Laser (VCSEL) in response to induced perturbations and for two different cases of polarized optical injection, namely, parallel and orthogonal. Furthermore, reproducible spiking responses are demonstrated experimentally at sub-nanosecond speed resolution and with a controlled number of spikes fired. This work opens therefore exciting research avenues for the use of VCSELs in ultrafast neuromorphic photonic systems for non-traditional computing applications, such as all-optical binary-to-spiking format conversion and spiking information encoding.

  2. Four-wave mixing stability in hybrid photonic crystal fibers with two zero-dispersion wavelengths.

    PubMed

    Sévigny, Benoit; Vanvincq, Olivier; Valentin, Constance; Chen, Na; Quiquempois, Yves; Bouwmans, Géraud

    2013-12-16

    The four-wave mixing process in optical fibers is generally sensitive to dispersion uniformity along the fiber length. However, some specific phase matching conditions show increased robustness to longitudinal fluctuations in fiber dimensions, which affect the dispersion, even for signal and idler wavelengths far from the pump. In this paper, we present the method by which this point is found, how the fiber design characteristics impact on the stable point and demonstrate the stability through propagation simulations using the non-linear Schrödinger equation. PMID:24514659

  3. Properties of the upper tropospheres of Uranus and Neptune derived from observations at visible to near-infrared wavelengths

    SciTech Connect

    Bergstralh, J.T.; Baines, K.H.

    1984-10-01

    Photons at wavelengths between 0.3 and 4.5 microns penetrate the atmospheres of Uranus and Neptune to pressures between about 0.01 bar and 10 bars. This pressure range brackets the radiative convective boundary in both atmospheres and is therefore designated upper troposphere. Physical processes which govern the transfer of radiation in Uranus's and Neptune's atmospheres at these wavelengths include Rayleigh/Raman scattering by hydrogen, scattering and broadband absorption by suspended aerosol particles and absorption in discrete bands and lines by methane and hydrogen. Consequently, tropospheric properties constrained by observations at these wavelengths include optical properties and distribution of aerosol particles, methane/hydrogen ratio, and ortho/para hydrogen ratio. Recent observations of Uranus and Neptune in this spectral range, are reviewed and compared with predictions based on models of the atmospheric structures. Significant results for Uranus include the presence of an opaque lower boundary to the visible atmosphere very near the level corresponding to 2 bars pressure, and consequently a methane/hydrogen ratio no less than 3 percent.

  4. Intersubband transitions in nonpolar GaN/Al(Ga)N heterostructures in the short- and mid-wavelength infrared regions

    SciTech Connect

    Lim, C. B.; Beeler, M.; Ajay, A.; Lähnemann, J.; Bellet-Amalric, E.; Monroy, E.; Bougerol, C.

    2015-07-07

    This paper assesses nonpolar m- and a-plane GaN/Al(Ga)N multi-quantum-wells grown on bulk GaN for intersubband optoelectronics in the short- and mid-wavelength infrared ranges. The characterization results are compared to those for reference samples grown on the polar c-plane, and are verified by self-consistent Schrödinger-Poisson calculations. The best results in terms of mosaicity, surface roughness, photoluminescence linewidth and intensity, as well as intersubband absorption are obtained from m-plane structures, which display room-temperature intersubband absorption in the range from 1.5 to 2.9 μm. Based on these results, a series of m-plane GaN/AlGaN multi-quantum-wells were designed to determine the accessible spectral range in the mid-infrared. These samples exhibit tunable room-temperature intersubband absorption from 4.0 to 5.8 μm, the long-wavelength limit being set by the absorption associated with the second order of the Reststrahlen band in the GaN substrates.

  5. Intersubband transitions in nonpolar GaN/Al(Ga)N heterostructures in the short- and mid-wavelength infrared regions

    NASA Astrophysics Data System (ADS)

    Lim, C. B.; Beeler, M.; Ajay, A.; Lähnemann, J.; Bellet-Amalric, E.; Bougerol, C.; Monroy, E.

    2015-07-01

    This paper assesses nonpolar m- and a-plane GaN/Al(Ga)N multi-quantum-wells grown on bulk GaN for intersubband optoelectronics in the short- and mid-wavelength infrared ranges. The characterization results are compared to those for reference samples grown on the polar c-plane, and are verified by self-consistent Schrödinger-Poisson calculations. The best results in terms of mosaicity, surface roughness, photoluminescence linewidth and intensity, as well as intersubband absorption are obtained from m-plane structures, which display room-temperature intersubband absorption in the range from 1.5 to 2.9 μm. Based on these results, a series of m-plane GaN/AlGaN multi-quantum-wells were designed to determine the accessible spectral range in the mid-infrared. These samples exhibit tunable room-temperature intersubband absorption from 4.0 to 5.8 μm, the long-wavelength limit being set by the absorption associated with the second order of the Reststrahlen band in the GaN substrates.

  6. Anodic fluoride passivation of type II InAs/GaSb superlattice for short-wavelength infrared detector

    NASA Astrophysics Data System (ADS)

    Zhang, Li Xue; Sun, Wei Guo; Lv, Yan Qiu; Li, Mo; Ding, Jia Xin; Si, Jun Jie

    2015-02-01

    One of the major challenges of antimonide-based devices arises owing to the large number of surface states generated during fabrication processes. Surface passivation and subsequent capping of the surfaces are absolutely essential for any practical applicability of this material system. In this paper, we proposed a new passivation method (zinc sulfide coating after anodic fluoride) for InAs/GaSb superlattice infrared detectors. InAs/GaSb superlattice short-wavelength infrared materials were grown by molecular beam epitaxy on GaSb (100) substrates. A GaSb buffer layer, which can decrease the occurrence of defects with similar pyramidal structure, was grown for optimized superlattice growth condition. High resolution X-ray diffraction indicated that the period of the superlattice corresponding to fourth satellite peak was 39.77 Å. The atomic force microscopy images show the roughness was below 1.7 nm. The result of photoresponse spectra shows that the cutoff wavelength was 3.05 μm at 300 K.

  7. Anodic fluoride passivation of type II InAs/GaSb superlattice for short-wavelength infrared detector

    NASA Astrophysics Data System (ADS)

    Zhang, Li Xue; Sun, Wei Guo; Lv, Yan Qiu; Li, Mo; Ding, Jia Xin; Si, Jun Jie

    2014-09-01

    One of the major challenges of antimonide-based devices arises owing to the large number of surface states generated during fabrication processes. Surface passivation and subsequent capping of the surfaces are absolutely essential for any practical applicability of this material system. In this paper, we proposed a new passivation method (zinc sulfide coating after anodic fluoride) for InAs/GaSb superlattice infrared detectors. InAs/GaSb superlattice short-wavelength infrared materials were grown by molecular beam epitaxy on GaSb (100) substrates. A GaSb buffer layer, which can decrease the occurrence of defects with similar pyramidal structure, was grown for optimized superlattice growth condition. High resolution X-ray diffraction indicated that the period of the superlattice corresponding to fourth satellite peak was 39.77 Å. The atomic force microscopy images show the roughness was below 1.7 nm. The result of photoresponse spectra shows that the cutoff wavelength was 3.05 μm at 300 K.

  8. Long-wavelength infrared camera (LWIRC): a 10 micron camera for the Keck telescope

    NASA Astrophysics Data System (ADS)

    Wishnow, Edward H.; Danchi, William C.; Tuthill, Peter G.; Wurtz, Ronald E.; Jernigan, J. G.; Arens, John F.

    1998-08-01

    The long wavelength IR camera is a facility instrument for the Keck Observatory designed to operate at the f/25 forward Cassegrain focus of the Keck I telescope. The camera operates over the wavelength band 7-13 micrometers using ZnSe transmissive optics. A set of filters, a circular variable filter, and a mid-IR polarizer are available, as are three plate scales: 0.05 inch, 0.10 inch, 0.12 inch per pixel. The camera focal plane array and optics are cooled using liquid helium. The system has been refurbished with a 128 X 128 pixel Si:As detector array. The electronics readout system used to clock the array is compatible wit both the hardware and software of the other Keck IR instruments NIRC and LWS. A new pre-amplifier/A-D converter has been designed and constructed which decreases greatly the system susceptibility to noise.

  9. Extreme limb profiles of the sun at far-infrared and submillimeter wavelengths

    NASA Technical Reports Server (NTRS)

    Lindsey, C.; Becklin, E. E.; Orrall, F. Q.; Werner, M. W.; Jefferies, J. T.; Gatley, I.

    1986-01-01

    Thirty, 50, 100, and 200 microns solar limb intensity profiles determined with arcsecond resolution from airborne observations of the occultation of the solar limb during the total eclipse of 1981 July 31 are presented. Two points of particular importance emerge: (1) the longer-wavelength (100 and 200 micron) limbs are significantly brighter than disk center. At 200 microns the extreme limb is about 1.22 times the brightness of disk center. This is consistent with the 6000 K temperature-plateau structure of the model chromospheres of Vernazza, Avrett, and Loeser (1973, Ap. J., 184, 605; 1981; Ap. J. Suppl., 45, 635;) and (2) the longer wavelength limbs are extended significantly further above the visible limb than Vernazza, Avrett, and Loeser predict. These results provide a strong basis for modeling of the solar chromosphere free from the assumption of gravitational-hydrostatic equilibrium.

  10. Enhanced vacuum laser-impulse coupling by volume absorption at infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Phipps, C. R., Jr.; Harrison, R. F.; Shimada, T.; York, G. W.; Turner, R. F.

    1990-03-01

    This paper reports measurements of vacuum laser impulse coupling coefficients as large as 90 dyne/W, obtained with single microsec-duration CO2 laser pulses incident on a volume-absorbing, cellulose-nitrate-based plastic. This result is the largest coupling coefficient yet reported at any wavelength for a simple, planar target in vacuum, and partly results from expenditure of internal chemical energy in this material. Enhanced coupling was also observed in several other target materials that are chemically passive, but absorb light in depth at 10- and 3-micron wavelengths. The physical distinctions are discussed between this important case and that of simple, planar surface absorbers (such as metals) which were studied in the same experimental series, in light of the predictions of a simple theoretical model.

  11. pH Measurement Using Dual-Wavelength Fluorescent Ratio by Two-Photon Excitation for Mitochondrial Activity

    NASA Astrophysics Data System (ADS)

    Kanazashi, Yasuaki; Li, Yongbo; Onojima, Takumi; Iwami, Kentaro; Ohta, Yoshihiro; Umeda, Norihiro

    2012-11-01

    A mitochondrion has a pH gradient between the two sides of its inner membrane in order to produce adenosine triphosphate (ATP). Because ATP depletion causes numerous diseases, the measurement of the pH value around the mitochondrion is expected to clarify the mechanism of these diseases. In this study, a dual-wavelength pH-sensitive dye was excited by two-photon absorption initiated using a femtosecond pulse laser. In addition, fluorescence from the dye was directly collected from the fluorescent point using the collection-mode probe of a scanning near-field optical microscope. By this proposed method, a pH calibration curve was obtained from the fluorescent intensity ratio of the dye solution, and temporal pH variations with 0.1 s time resolution following the addition of acid were observed. Moreover, mitochondrial activity on the basis of the pH changes was successfully observed in three different mitochondrial densities.

  12. Programmable multi-wavelength filter with Mach-Zehnder interferometer embedded in ethanol filled photonic crystal fiber.

    PubMed

    Zhao, Zhiyong; Tang, Ming; Liao, Huiqi; Ren, Guobin; Fu, Songnian; Yang, Fang; Shum, Perry Ping; Liu, Deming

    2014-04-01

    We experimentally demonstrated a free spectrum range (FSR) tunable comb filter based on a programmable thermo-controlled Mach-Zehnder interferometer. The device is constructed by sandwiching a length of ethanol-filled photonic crystal fiber between single-mode fibers. A digital thermal printer head is used to facilitate the interference as well as to adjust the phase difference by selectively activating the independent heating elements, thus the FSR can be digitally tuned conveniently. The filter shows a feature of periodic equalized passbands with flat-top steep-edge as well as a high extinction ratio over a very wide range of wavelengths from 1.52 to 1.58 μm. PMID:24686709

  13. Near infrared spectroscopy for mastitis diagnosis: Two-dimensional correlation study in short wavelength region

    NASA Astrophysics Data System (ADS)

    Tsenkova, Roumiana; Murayama, Koichi; Kawano, Sumio; Wu, Yuqing; Toyoda, Kiyohiko; Ozaki, Yukihiro

    2000-03-01

    We describe the application of two-dimensional correlation spectroscopic (2DCOS) technique for mastitic diagnosis. Seven average spectra in the short wavelength region (700-1100 nm) of mastitic levels separated from healthy to disease were subjected to 2DCOS analysis. Synchronous correlation map clearly showed water and fat bands. Asynchronous correlation map indicated the dynamical variations of milk constituents in milk occurred when a cow gets mastitis.

  14. Method for measuring thermal properties using a long-wavelength infrared thermal image

    DOEpatents

    Walker, Charles L.; Costin, Laurence S.; Smith, Jody L.; Moya, Mary M.; Mercier, Jeffrey A.

    2007-01-30

    A method for estimating the thermal properties of surface materials using long-wavelength thermal imagery by exploiting the differential heating histories of ground points in the vicinity of shadows. The use of differential heating histories of different ground points of the same surface material allows the use of a single image acquisition step to provide the necessary variation in measured parameters for calculation of the thermal properties of surface materials.

  15. A Wavelength Optimization Study on Visible and Infrared Propagation Systems in Coastal Environments

    NASA Technical Reports Server (NTRS)

    Reid, J. S.; Tsay, Si-Chee; Moision, W. K.; Gasso, S.; Cook, J. R.; Westphal, D. L.; Paulus, R. A.; Bucholtz, A.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Electro-optical (EO) systems employed for communications, surveillance and weapons systems are commonly assessed in the North American and European continents. However, the atmospheric propagation environment in these regions is often dissimilar to most other parts of the world. In particular, atmospheric dust, industrial pollution, and smoke frequently reduce visibility to less than 5 km in Asia and South America significantly hampering EO system performance. Because atmospheric aerosol species vary considerably in size and chemistry, optimal wavelengths for EO systems vary from region to region. In this paper we examine the extinction effects from aerosol particles and water vapor on a regional basis. Theoretical studies are coupled with visibility and satellite climatologies to make an assessment for the coastal regions of the world. While longer wavelengths permit higher transmission by particles in regions significantly hampered by fine mode particles (such as industrial pollution and smoke), this advantage is commonly offset by high extinction values from water vapor. This offsetting effect is particularly strong in industrial and developing countries in the tropics and sub-tropics such as Southeast Asia and South America. Conversely, the advantage of low water vapor concentrations in longer wavelengths is offset by high mass-extinction efficiencies of atmospheric dust in this portion of the spectrum.

  16. Interference multilayer antireflection coatings for two wavelengths in the near infrared

    NASA Astrophysics Data System (ADS)

    Pencheva, Tamara G.; Nenkov, Milen; Michev, Javor

    2001-04-01

    The investigation deals with analysis of antireflection coatings of two transparent materials with high (H) and low (L) refractive index for two wavelengths 1.30 micrometer and 1.55 micrometer in the near IR on glass/silica substrates. The results are obtained by numerical optimization approach which algorithms are realized using programming language DELPHI. The initial structures of LHL three-layer and LHLH four-layer coating (optimized for both wavelengths) are modifications of double-layer antireflection coating for one wavelength 1.4 micrometer. It is shown that the highest transmittance near 1.30 and 1.55 micrometer (practically equal to 100%) shows LHLH four-layer coating structure. The total physical and optical thickness of optimized LHLH four-layer coating is smaller than corresponding value for optimized LHL three-layer coating. Four-layer LHLH coating is more stable with respect to small n and d variations and corresponding transmittance changes are less than in case of LHL three-layer coating.

  17. Selective treatment of carious dentin using a mid-infrared tunable pulsed laser at 6 μm wavelength range

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    Optical technologies have good potential for caries detection, prevention, excavation, and the realization of minimal intervention dentistry. This study aimed to develop a selective excavation technique of carious tissue using the specific absorption in 6 μm wavelength range. Bovine dentin demineralized with lactic acid solution was used as a carious dentin model. A mid-infrared tunable pulsed laser was obtained by difference-frequency generation technique. The wavelength was tuned to 6.02 and 6.42 μm which correspond to absorption bands called amide I and amide II, respectively. The laser delivers 5 ns pulse width at a repetition rate of 10 Hz. The morphological change after irradiation was observed with a scanning electron microscope, and the measurement of ablation depth was performed with a confocal laser microscope. At λ = 6.02 μm and the average power density of 15 W/cm2, demineralized dentin was removed selectively with less-invasive effect on sound dentin. The wavelength of 6.42 μm also showed the possibility of selective removal. High ablation efficiency and low thermal side effect were observed using the nanosecond pulsed laser with λ = 6.02 μm. In the near future, development of compact laser device will open the minimal invasive laser treatment to the dental clinic.

  18. Wavelength-tunable visible to near-infrared photoluminescence of carbon dots: the role of quantum confinement and surface states

    NASA Astrophysics Data System (ADS)

    Ghamsari, Morteza Sasani; Bidzard, Ashkan Momeni; Han, Wooje; Park, Hyung-Ho

    2016-04-01

    Carbon quantum dots (C-QDs) with different size distributions and surface characteristics can exhibit good emission properties in the visible and near-infrared (NIR) regions, which can be applicable in optoelectronic devices as well as biomedical applications. Optical properties of colloidal C-QDs in distilled water at different concentrations produced using a method of alkali-assisted surfactant-free oxidation of cellulose acetate is presented. The structural and optical properties of colloidal C-QDs at different concentrations were investigated, with the aim of clarifying the main mechanisms of photoluminescence emissions. We observed a wide range of tunable visible to NIR emissions with good stability from the C-QD colloids at different applied excitation wavelengths. The colloids show dual emissions with maxima at ˜420 and 775 nm (blue and NIR emissions) when excited at the wavelength range near the energy gaps of the C-QDs. Moreover, by increasing the excitation wavelength, tunable visible emissions at the spectral range of 475 to 550 nm are observed. A detailed analysis of the results shows that the blue and NIR luminescence of colloidal C-QDs originate from the oxide-related surface effects whereas quantum confinement is the responsible mechanism for tunable visible emissions of the C-QD colloid.

  19. Near-infrared spectroscopy with Spectroscopic technique with wide range of wavelength information detects tissue oxygenation level clearly

    NASA Astrophysics Data System (ADS)

    Eda, Hideo; Aoki, Hiromichi; Eura, Shigeru; Ebe, Kazutoshi

    2010-02-01

    Near-infrared spectroscopy (NIRS) is based on the modified-Lambert-Beer's law that changes in absorbance are proportional to changes in hemoglobin parameters. Majority of the conventional measurement methods uses only two or three wavelengths. In this research, basic examination of NIRS measurement was approached by acquiring wide range of wavelength information. Arterial occlusion task was performed by using the blood pressure cuff around the upper arm. Pressure of 200mmHg was then applied for about 3 minutes. During the arterial occlusion, the spectrum of the lower arm muscles was measured every 15 seconds, within the range of 600 to 1100nm. The secondary derivative spectrum was calculated from the measured spectrum. Arterial occlusion is a task which changes the oxygenation level of the tissue. The change can be regarded as the change of the spectrum form, not as the change of the baseline. Furthermore, it was found that other wavelength bands hold information correlating to this arterial occlusion task.

  20. MEMS infrared approaches to detector based on nonlinear oscillation and wavelength selective emitter using surface plasmon polariton

    NASA Astrophysics Data System (ADS)

    Sasaki, Minoru; Kumagai, Shinya

    2014-03-01

    The suspended MEMS structure is suitable for reducing the energy loss due to the thermal conduction. There is the possibility that IR photon energy can be well-controlled to generate some physical effects. A new method bases on the nonlinear oscillation for the detector. The thin film torsional spring exhibits a large hard spring effect when the deflection occurs in the out-of-plane direction of the film. When IR is absorbed, the resonator bends due to the thermal expansion. The torsional spring becomes harder increasing the resonant frequency. The frequency measurement is suited for the precise sensing. The device response is measured using the laser (wavelength of 650nm). The resonant frequency is 88-94kHz. Q factor is about 1600 in vacuum (1Pa). The sensitivity is -0.144[kHz/(kW/m2)]. As for the emitter, nondispersive IR gas sensor is considered. The molecules have their intrinsic absorptions. CO2 absorbs the wavelength 4.2- 4.3μm. The major incandescent light bulbs have the broad spectrum emitting IR which is not used for gas sensing. The wavelength selectivity at the gas bandwidth will improve the efficiency. A new principle uses the microheater placed facing to the grating. SPP is excited carrying IR energy on the grating surface. IR emission is the reverse process of excitation occurring at the output end. The emission spectra show SPP related peak having the width of 190nm. When the input power increases from 0.3 to 1.9W, the peak at wavelength of 3.5μm becomes clearer.

  1. Practical approach for a rod-connected diamond photonic crystal operating at optical wavelengths

    NASA Astrophysics Data System (ADS)

    Aoki, Kanna

    2009-11-01

    Production of a rod-connected diamond (RCD) photonic crystal structure in a semiconductor material is proposed. Periodic shifting of only one building block can create a complicated three-dimensional network, with a RCD structure exhibiting a full bandgap as wide as 0.20 on a gap/midgap (Δω /ωM) basis. A point defect cavity in the structure sustains single-mode resonance throughout the operative range because of its low symmetry. The resonant mode's highest quality factor (Q-factor) was calculated as 1.5×104 for a crystal of 11.5ax×4.25ay×12az for ai (i =x,y,z) representing three axes' period lengths.

  2. All-Optical 1-to-8 Wavelength Multicasting at 20 Gbit/s Exploiting Self-Phase Modulation in Dispersion Flattened Highly Nonlinear Photonic Crystal Fiber

    PubMed Central

    Hui, Zhan-Qiang

    2014-01-01

    All-optical multicasting of performing data routing from single node to multiple destinations in the optical domain is promising for next generation ultrahigh-peed photonic networks. Based on the self-phase modulation in dispersion flattened highly nonlinear photonic crystal fiber and followed spectral filtering, simultaneous 1-to-8 all-optical wavelength multicasting return-to-zero (RZ) signal at 20 Gbit/s with 100 GHz channel spaced is achieved. Wavelength tunable range and dynamic characteristic of proposed wavelength multicasting scheme is further investigated. The results show our designed scheme achieve operation wavelength range of 25 nm, OSNR of 32.01 dB and Q factor of 12.8. Moreover, the scheme has simple structure as well as high tolerance to signal power fluctuation. PMID:24711738

  3. The Quiescent Accretion Disk in IP Pegasi at Near-Infrared Wavelengths

    NASA Astrophysics Data System (ADS)

    Froning, C. S.; Robinson, E. L.; Welsh, William F.; Wood, Janet H.

    1999-09-01

    We present near-infrared, H-band (1.45-1.85 μm) observations of an eclipsing dwarf nova, IP Peg, in quiescence. The light curves are composed of ellipsoidal variations from the late-type secondary star and emission from the accretion disk and the bright spot. The light curves have two eclipses: a primary eclipse of the accretion disk and the bright spot by the companion star, and a secondary eclipse of the companion star by the disk. The ellipsoidal variations of the secondary star were modeled and subtracted from the data. The resulting light curve shows a pronounced double-hump variation. The double-hump profile resembles those seen in the light curves of WZ Sge and AL Com and likely originates in the accretion disk. The primary eclipse was modeled using maximum entropy disk mapping techniques. The accretion disk has a flat intensity distribution and a cool brightness temperature (Tbr~=3000 K) in the near-infrared. Superimposed on the face of the disk is the bright spot (Tbr~=10,000 K); the position of the bright spot is different from the observed range of visible bright spot positions. The near-infrared accretion disk flux is dominated by optically thin emission. The secondary eclipse indicates the presence of some occulting medium in the disk, but the eclipse depth is too shallow to be caused by a fully opaque accretion disk.

  4. Plant lighting system with five wavelength-band light-emitting diodes providing photon flux density and mixing ratio control

    PubMed Central

    2012-01-01

    Background Plant growth and development depend on the availability of light. Lighting systems therefore play crucial roles in plant studies. Recent advancements of light-emitting diode (LED) technologies provide abundant opportunities to study various plant light responses. The LED merits include solidity, longevity, small element volume, radiant flux controllability, and monochromaticity. To apply these merits in plant light response studies, a lighting system must provide precisely controlled light spectra that are useful for inducing various plant responses. Results We have developed a plant lighting system that irradiated a 0.18 m2 area with a highly uniform distribution of photon flux density (PFD). The average photosynthetic PFD (PPFD) in the irradiated area was 438 micro-mol m–2 s–1 (coefficient of variation 9.6%), which is appropriate for growing leafy vegetables. The irradiated light includes violet, blue, orange-red, red, and far-red wavelength bands created by LEDs of five types. The PFD and mixing ratio of the five wavelength-band lights are controllable using a computer and drive circuits. The phototropic response of oat coleoptiles was investigated to evaluate plant sensitivity to the light control quality of the lighting system. Oat coleoptiles irradiated for 23 h with a uniformly distributed spectral PFD (SPFD) of 1 micro-mol m–2 s–1 nm–1 at every peak wavelength (405, 460, 630, 660, and 735 nm) grew almost straight upwards. When they were irradiated with an SPFD gradient of blue light (460 nm peak wavelength), the coleoptiles showed a phototropic curvature in the direction of the greater SPFD of blue light. The greater SPFD gradient induced the greater curvature of coleoptiles. The relation between the phototropic curvature (deg) and the blue-light SPFD gradient (micro-mol m–2 s–1 nm–1 m–1) was 2 deg per 1 micro-mol m–2 s–1 nm–1 m–1. Conclusions The plant lighting system, with a computer with a graphical user interface

  5. A Stable Dual-wavelength Thulium-doped Fiber Laser at 1.9 μm Using Photonic Crystal Fiber

    NASA Astrophysics Data System (ADS)

    Soltanian, M. R. K.; Ahmad, H.; Khodaie, A.; Amiri, I. S.; Ismail, M. F.; Harun, S. W.

    2015-10-01

    A stable dual-wavelength thulium-doped fiber laser operating at 1.9 μm using a short length of photonic crystal fiber (PCF) has been proposed and demonstrated. The photonics crystal fiber was 10 cm in length and effectively acted as a Mach-Zehnder interferometry element with a free spectral range of 0.2 nm. This dual-wavelength thulium-doped fiber laser operated steadily at room temperature with a 45 dB optical signal-to-noise-ratio.

  6. A Stable Dual-wavelength Thulium-doped Fiber Laser at 1.9 μm Using Photonic Crystal Fiber.

    PubMed

    Soltanian, M R K; Ahmad, H; Khodaie, A; Amiri, I S; Ismail, M F; Harun, S W

    2015-01-01

    A stable dual-wavelength thulium-doped fiber laser operating at 1.9 μm using a short length of photonic crystal fiber (PCF) has been proposed and demonstrated. The photonics crystal fiber was 10 cm in length and effectively acted as a Mach-Zehnder interferometry element with a free spectral range of 0.2 nm. This dual-wavelength thulium-doped fiber laser operated steadily at room temperature with a 45 dB optical signal-to-noise-ratio. PMID:26455713

  7. A Stable Dual-wavelength Thulium-doped Fiber Laser at 1.9 μm Using Photonic Crystal Fiber

    PubMed Central

    Soltanian, M. R. K.; Ahmad, H.; Khodaie, A.; Amiri, I. S.; Ismail, M. F.; Harun, S. W.

    2015-01-01

    A stable dual-wavelength thulium-doped fiber laser operating at 1.9 μm using a short length of photonic crystal fiber (PCF) has been proposed and demonstrated. The photonics crystal fiber was 10 cm in length and effectively acted as a Mach-Zehnder interferometry element with a free spectral range of 0.2 nm. This dual-wavelength thulium-doped fiber laser operated steadily at room temperature with a 45 dB optical signal-to-noise-ratio. PMID:26455713

  8. Measurements of partial cross sections and photoelectron angular distributions for the photodetachment of Fe- and Cu- at visible photon wavelengths

    NASA Astrophysics Data System (ADS)

    Covington, A. M.; Duvvuri, Srividya S.; Emmons, E. D.; Kraus, R. G.; Williams, W. W.; Thompson, J. S.; Calabrese, D.; Carpenter, D. L.; Collier, R. D.; Kvale, T. J.; Davis, V. T.

    2007-02-01

    Photodetachment cross sections and the angular distributions of photoelectrons produced by the single-photon detachment of the transition metal negative ions Fe- and Cu- have been measured at four discrete photon wavelengths ranging from 457.9 to 647.1nm (2.71-1.92eV) using a crossed-beams laser photodetachment electron spectrometry (LPES) apparatus. Photodetachment cross sections were determined by comparing the photoelectron yields from the photodetachment of Fe- to those of Cu- and C- , which have known absolute photodetachment cross sections. Using the measured photodetachment cross sections, radiative electron attachment cross sections were calculated using the principle of detailed balance. Angular distributions were determined by measurements of laboratory frame, angle-, and energy-resolved photoelectrons as a function of the angle between the linear laser polarization vector and the momentum vector of the collected photoelectrons. Values of the asymmetry parameter have been determined by nonlinear least-squares fits to these angular distributions. The measured asymmetry parameters are compared to predictions of photodetachment models including Cooper and Zare’s dipole approximation theory [J. Cooper and R. N. Zare, J. Chem. Phys. 48, 942 (1968)], and the angular momentum transfer theory developed by Fano and Dill [Phys. Rev. A 6, 185 (1972)].

  9. Stable narrow spacing dual-wavelength Q-switched graphene oxide embedded in a photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Soltanian, M. R. K.; Alimadad, M.; Harun, S. W.

    2014-10-01

    An ultra-stable dual-wavelength saturable absorber based on a cladding-embedded commercial graphene oxide (GO) solution by capillary action in a solid core photonic crystal fiber (PCF) is demonstrated for the first time. The saturation absorption property is achieved through evanescent coupling between the guided light and the cladding-filled graphene layers. Stable spacing dual-wavelength fiber lasing is attained by controlling the polarization state of a simple 0.9 m long ring of highly doped Leikki Er80-8/125 erbium-doped fiber as the primary gain medium with PCF, polarization controller and tunable bandpass filter. Embedded GO is used to generate the desired pulsed output, and the laser is capable of generating pulses having a repetition rate of 24 kHz with an average output power and pulse energy of 0.167 mW and 8.98 nJ, respectively, at the maximum pump power of 220 mW.

  10. Detection of Infrared Photons Using the Electronic Stress in Metal-Semiconductor Interfaces

    SciTech Connect

    Datskos, P.G.; Datskou, I.; Egert, C.M.; Rjic, S.

    1999-04-05

    It is well known that the work function of metals decreases when they are placed in a nonpolar liquid. A similar decrease occurs when the metal is placed into contact with a semiconductor forming a Schottky barrier. We report on a new method for detecting photons using the stress caused by photo-electrons emitted from a metal film surface in contact with a semiconductor microstructure. The photoelectrons diffuse into the microstructure and produce an electronic stress. The photon detection results from the measurement of the photo-induced bending of the microstructure. Internal photoemission has been used in the past to detect photons, however, in those cases the detection was accomplished by measuring the current due to photoelectrons and not due to electronic stress. Small changes in position (displacement) of microstructures are routinely measured in atomic force microscopy (AFM) where atomic imaging of surfaces relies on the measurement of small changes (< l0{sup -9} m) in the bending of microcantilevers. In the present work we studied the photon response of Si microcantilevers coated with a thin film of Pt. The Si microcantilevers were 500 nm thick and had a 30 nm layer of Pt. Photons with sufficient energies produce electrons from the platinum-silicon interface which diffuse into the Si and produce an electronic stress. Since the excess charge carriers cause the Si microcantilever to contract in length but not the Pt layer, the bimaterial microcantilever bends. In our present studies we used the optical detection technique to measure the photometric response of Pt-Si microcantilevers as a function of photon energy. The charge carriers responsible for the photo-induced stress in Si, were produced via internal photoemission using a diode laser with wavelength {lambda} = 1550 nm.

  11. Asymmetric photonic resonances in GaN slab waveguide for mid infrared selective filters.

    PubMed

    Vangala, S R; Avrutsky, I; Keiffer, P; Nader, N; Walker, D; Cleary, J W; Hendrickson, J R

    2014-10-01

    We demonstrate a spectrally selective reflector that exploits asymmetric photonic resonances of a 1D photonic crystal. The proposed spectrally selective reflector has a very simple structure - essentially just a single high-index slab of GaN, properly perforated, and supported by a transparent sapphire substrate. With the proper 1D array design, nearly 100% reflection is achieved with a narrow spectral width between 10 cm⁻¹ - 18 cm⁻¹, while the background reflection remains low across the entire mid-IR range. The reflection peak can be tuned over a large wavelength span based on physical parameters. Resonant transmission dips in the experimentally measured spectra corroborate the device theory and simulation, exhibiting the narrowband low-background mid-IR reflection as predicted. PMID:25322049

  12. The solid state photomultiplier: Status of photon counting beyond the near-infrared

    NASA Technical Reports Server (NTRS)

    Hays, K. M.; Laviolette, R. A.; Stapelbroek, M. G.; Petroff, M. D.

    1989-01-01

    Rockwell International's Solid State Photomultiplier (SSPM) is an impurity-band avalanche device which can count individual photons with wavelengths between 0.4 and 28 micrometers. Its response to a photon is a pulse of between 10(exp 4) and 10(exp 5) conduction electrons, making it an important device for use in phenomenology. The characteristics of the SSPM make it a potentially important device for use in astronomical applications. Contract NAS2-12400 was initiated in June 1986 to conduct modeling and characterization studies of the SSPM to provide a basis for assessing its use in astronomical systems. Some SSPM models and results of measurements which characterize the group of SSPMs recently fabricated on this contract are discussed.

  13. X-ray Photon Correlation Spectroscopy: A New Probe of Short Wavelength Dynamics

    NASA Astrophysics Data System (ADS)

    Dierker, S. B.

    1996-03-01

    The new field of x-ray photon correlation spectroscopy (XPCS) offers an unprecedented opportunity to extend the range of length scales over which a material's low frequency dynamics can be studied down to interatomic spacings. The critical development which has now made XPCS a feasible technique is the high brightness of insertion devices at second and third generation synchrotron sources. In this talk, I will describe the principles of the XPCS technique and how it is practiced, as well as its potential use for a variety of important problems in the low frequency dynamics of condensed matter systems, such as complex fluids, glasses, surfaces, and metallic alloys. Illustrations will be drawn from our(Research done in collaboration with R. Pindak, R. M. Fleming, I. K. Robinson, L. Berman, G. Grubel, and D. L. Abernathy. S.B.D. supported by NSF DMR92-17956. I.K.R. supported by NSF MDR 93-15691. The NSLS is supported by DOE DE-AC02-76CH00016.) results(S. B. Dierker, R. Pindak, R. M. Fleming, I. K. Robinson, L. Berman, Phys. Rev. Lett. 75), 449 (1995). on using XPCS to study the Brownian motion of a gold colloid. We made small angle x-ray scattering measurements of the static structure factor of an optically opaque gold colloid dispersed in the viscous liquid glycerol. We discovered a novel effect due to photoemission induced charging of the gold colloid which could be suppressed by the addition of salt. We determined the dynamic correlation functions for the Brownian motion of the colloid particles at wavevectors between 10-3 <= q <= 10-2 Åwhich extends well beyond the range of visible light scattering. The resulting diffusion coefficient is very q dependent, scaling approximately as D(q) = D_o/S(q). The results of recent progress in using the Prototype Small Gap Undulator (PSGU) at beam line X13 at the NSLS will also be described. We(Research done in collaboration with L. Berman, Z. Yin, and E. Dufresne.) have achieved a coherent flux of > 10^10 photons/second in a

  14. Detection of the Detached Dust Shell of U Antliae at Mid-infrared Wavelengths with AKARI/IRC

    NASA Astrophysics Data System (ADS)

    Arimatsu, Ko; Izumiura, Hideyuki; Ueta, Toshiya; Yamamura, Issei; Onaka, Takashi

    2011-03-01

    We report mid-infrared (MIR) imaging observations of the carbon star U Ant made with the Infrared Camera (IRC) on board AKARI. Subtraction of the artifacts and extended point-spread function of the central star reveals the detached dust shell around the carbon star at MIR wavelengths (15 and 24 μm) for the first time. The observed radial brightness profiles of the MIR emission are well explained by two shells at 43'' and 50'' from the central star detected in optical scattered light observations. Combining Herschel/PACS, AKARI/FIS, and AKARI/IRC data, we obtain the infrared spectral energy distribution (SED) of the thermal emission from the detached shell of U Ant in a wide infrared spectral range of 15-160 μm. Thermal emission of amorphous carbon grains with a single temperature cannot account for the observed SED from 15 to 160 μm: it underestimates the emission at 15 μm. Alternatively, the observed SED is fitted by the model in which amorphous carbon grains in the two shells have different temperatures of 60 and 104 K, which allocates most dust mass in the shell at 50''. This supports the previous suggestion that the 43'' shell is gas-rich and the 50'' shell is dust-rich. We suggest a possibility that the segregation of the gas and dust resulting from the drift motion of submicron-sized dust grains relative to the gas and that the hot dust component associated with the gas-rich shell is composed of very small grains that are strongly coupled with the gas.

  15. DETECTION OF THE DETACHED DUST SHELL OF U ANTLIAE AT MID-INFRARED WAVELENGTHS WITH AKARI/IRC

    SciTech Connect

    Arimatsu, Ko; Onaka, Takashi; Izumiura, Hideyuki; Ueta, Toshiya; Yamamura, Issei

    2011-03-10

    We report mid-infrared (MIR) imaging observations of the carbon star U Ant made with the Infrared Camera (IRC) on board AKARI. Subtraction of the artifacts and extended point-spread function of the central star reveals the detached dust shell around the carbon star at MIR wavelengths (15 and 24 {mu}m) for the first time. The observed radial brightness profiles of the MIR emission are well explained by two shells at 43'' and 50'' from the central star detected in optical scattered light observations. Combining Herschel/PACS, AKARI/FIS, and AKARI/IRC data, we obtain the infrared spectral energy distribution (SED) of the thermal emission from the detached shell of U Ant in a wide infrared spectral range of 15-160 {mu}m. Thermal emission of amorphous carbon grains with a single temperature cannot account for the observed SED from 15 to 160 {mu}m: it underestimates the emission at 15 {mu}m. Alternatively, the observed SED is fitted by the model in which amorphous carbon grains in the two shells have different temperatures of 60 and 104 K, which allocates most dust mass in the shell at 50''. This supports the previous suggestion that the 43'' shell is gas-rich and the 50'' shell is dust-rich. We suggest a possibility that the segregation of the gas and dust resulting from the drift motion of submicron-sized dust grains relative to the gas and that the hot dust component associated with the gas-rich shell is composed of very small grains that are strongly coupled with the gas.

  16. Fractal morphology of black carbon aerosol enhances absorption in the thermal infrared wavelengths.

    PubMed

    Heinson, William R; Chakrabarty, Rajan K

    2016-02-15

    In this Letter, we numerically calculate the mass absorption cross sections (MACs) of black carbon fractal aggregates in the thermal infrared solar spectrum. Compared to equivalent-size spheres, the MAC values of aggregates show a percent enhancement of ≈150 and 400 at small and large length scales, respectively. The absorption properties of aggregates with size parameters >1 surprisingly continued to remain in the Rayleigh optics regime. We explain this phenomenon using the Maxwell-Garnett effective medium theory and the concept of phase shift parameter. PMID:26872194

  17. A multi-wavelength classification method for polar stratospheric cloud types using infrared limb spectra

    NASA Astrophysics Data System (ADS)

    Spang, Reinhold; Hoffmann, Lars; Höpfner, Michael; Griessbach, Sabine; Müller, Rolf; Pitts, Michael C.; Orr, Andrew M. W.; Riese, Martin

    2016-08-01

    The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument on board the ESA Envisat satellite operated from July 2002 until April 2012. The infrared limb emission measurements represent a unique dataset of daytime and night-time observations of polar stratospheric clouds (PSCs) up to both poles. Cloud detection sensitivity is comparable to space-borne lidars, and it is possible to classify different cloud types from the spectral measurements in different atmospheric windows regions. Here we present a new infrared PSC classification scheme based on the combination of a well-established two-colour ratio method and multiple 2-D brightness temperature difference probability density functions. The method is a simple probabilistic classifier based on Bayes' theorem with a strong independence assumption. The method has been tested in conjunction with a database of radiative transfer model calculations of realistic PSC particle size distributions, geometries, and composition. The Bayesian classifier distinguishes between solid particles of ice and nitric acid trihydrate (NAT), as well as liquid droplets of super-cooled ternary solution (STS). The classification results are compared to coincident measurements from the space-borne lidar Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument over the temporal overlap of both satellite missions (June 2006-March 2012). Both datasets show a good agreement for the specific PSC classes, although the viewing geometries and the vertical and horizontal resolution are quite different. Discrepancies are observed between the CALIOP and the MIPAS ice class. The Bayesian classifier for MIPAS identifies substantially more ice clouds in the Southern Hemisphere polar vortex than CALIOP. This disagreement is attributed in part to the difference in the sensitivity on mixed-type clouds. Ice seems to dominate the spectral behaviour in the limb infrared spectra and may cause an overestimation in ice occurrence

  18. Vibrational relaxation of carbon monoxide studied by two-wavelength infrared emission

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.

    1973-01-01

    Experimental results are presented for the vibrational relaxation of pure carbon monoxide behind incident shock waves over the temperature range 4000 to 6300 K. The data were obtained as infrared emission from the fundamental and overtone vibrational band systems (in some of the experiments the two-band systems were recorded simultaneously). The data are consistent with present theories for the vibrational relaxation of diatomic molecules and can be interpreted in terms of an initial Boltzmann vibrational distribution relaxing toward final equilibrium via a continuous sequence of intermediate Boltzmann distributions.

  19. The sharpest view of the local AGN population at mid-infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Asmus, Daniel; Hönig, Sebastian F.; Gandhi, Poshak; Smette, Alain; Duschl, Wolfgang J.

    2014-07-01

    We present the largest mid-infrared (MIR) atlas of active galactic nuclei at sub-arcsec spatial scales containing 253 objects with a median redshift of 0.016. It comprises all available ground-based high-angular resolution MIR observations performed to date with 8-meter class telescopes and includes 895 photometric measurements. All types of AGN are present in the atlas, which also includes 80 per cent of the 9-month BAT AGN sample. Therefore, this atlas and its subsamples are very well-suited for AGN unification studies. A first application of the atlas is the extension of the MIR-X-ray luminosity correlation for AGN.

  20. Large-scale silicon photonic infrared scene projector by down conversion

    NASA Astrophysics Data System (ADS)

    Malyutenko, V. K.

    2012-06-01

    Aimed to pursue the development of infrared scene projection technology beyond the current state-of-the-art, we consider advantages of all-silicon bulk pixelless photonic projectors by light down conversion in comparison with thermal emitter micromachining devices available in the market. There are several reasons for this. First, there are firm evidences that the technology and performance of thermal emitters have already plateaued and future advances in the field do not seem assured. Second, we show that photonic devices by light down conversion evolved from scientific curiosity into technology poised to offer new capabilities to broadband projector applications. Finally, we demonstrate that silicon becomes enabling material for emitting structures operating in the short, mid, and long wave IR spectral bands.

  1. Tritium removal from contaminated water via infrared laser multiple-photon dissociation

    SciTech Connect

    Maienschein, J.L.; Magnotta, F.; Herman, I.P.; Aldridge, F.T.; Hsiao, P.

    1983-01-01

    Isotope separation by means of infrared-laser multiple-photon dissociation offers an efficient way to recover tritium from contaminated light or heavy water found in fission and fusion reactors. For tritium recovery from heavy water, chemical exchange of tritium into deuterated chloroform is followed by selective laser dissociation of tritiated chloroform and removal of the tritiated photoproduct, TCl. The single-step separation factor is at least 2700 and is probably greater than 5000. Here we present a description of the tritium recovery process, along with recent accomplishments in photochemical studies and engineering analysis of a recovery system.

  2. Design and analysis of equiangular spiral photonic crystal fiber for mid-infrared supercontinuum generation

    NASA Astrophysics Data System (ADS)

    Saini, T. S.; Baili, A.; Kumar, A.; Cherif, R.; Zghal, M.; Sinha, R. K.

    2015-11-01

    A design of equiangular spiral photonic crystal fiber (PCF) in As2Se3 chalcogenide glass is reported for mid-infrared supercontinuum generation. Supercontinuum covering the 1.2-15 μm molecular fingerprint region is achieved using only 8 mm long designed PCF pumped with 50 fs laser pulses of 500 W peak power. The structural parameters have been tailored for all-normal dispersion characteristic. Proposed structure has high nonlinearity (γ = 12474 W-1 km-1) at 3.5 μm with very low and flat dispersion -2.9 [ps/(nm × km)]. Supercontinuum with such broadening and high coherence degree is applicable for mid-infrared spectroscopy, gas sensing, early cancer diagnostics and free space communication.

  3. 2 μm wavelength range InP-based type-II quantum well photodiodes heterogeneously integrated on silicon photonic integrated circuits.

    PubMed

    Wang, Ruijun; Sprengel, Stephan; Muneeb, Muhammad; Boehm, Gerhard; Baets, Roel; Amann, Markus-Christian; Roelkens, Gunther

    2015-10-01

    The heterogeneous integration of InP-based type-II quantum well photodiodes on silicon photonic integrated circuits for the 2 µm wavelength range is presented. A responsivity of 1.2 A/W at a wavelength of 2.32 µm and 0.6 A/W at 2.4 µm wavelength is demonstrated. The photodiodes have a dark current of 12 nA at -0.5 V at room temperature. The absorbing active region of the integrated photodiodes consists of six periods of a "W"-shaped quantum well, also allowing for laser integration on the same platform. PMID:26480194

  4. Switchable multi-wavelength fiber ring laser based on a compact in-fiber Mach-Zehnder interferometer with photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Chen, W. G.; Lou, S. Q.; Feng, S. C.; Wang, L. W.; Li, H. L.; Guo, T. Y.; Jian, S. S.

    2009-11-01

    Switchable multi-wavelength fiber ring laser with an in-fiber Mach-Zehnder interferometer incorporated into the ring cavity serving as wavelength-selective filter at room temperature is demonstrated. The filter is formed by splicing a section of few-mode photonic crystal fiber (PCF) and two segments of single mode fiber (SMF) with the air-holes on the both sides of PCF intentionally collapsed in the vicinity of the splices. By adjusting the states of the polarization controller (PC) appropriately, the laser can be switched among the stable single-, dual- and triple-wavelength lasing operations by exploiting polarization hole burning (PHB) effect.

  5. High power broadband mid-infrared supercontinuum fiber laser using a novel chalcogenide AsSe2 photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Diouf, Mbaye; Ben Salem, Amine; Cherif, Rim; Wague, Ahmadou; Zghal, Mourad

    2016-05-01

    A high power supercontinuum (SC) based on a new type of chalcogenide AsSe2 material for broadband mid-infrared light source is numerically reported. Ultra-broadband coherent mid-IR SC generation with more than 3 octave-spanning from 1.7 to 14 μm in a novel design of chalcogenide AsSe2 photonic crystal fiber (PCF) is demonstrated. To the best of our knowledge and aiming to properly model the nonlinear propagation, an accurate fit of the Raman response function and the corresponding Raman gain of the novel AsSe2 chalcogenide glass are proposed numerically for the first time. The obtained SC is generated by pumping at 3.9 μm in the anomalous dispersion regime in only 8 mm long fiber. Our study shows that the initially generated SC from 150 fs pulse duration with 8.8 kW peak power exhibits high power proportion of more than 80% for wavelengths beyond 3 μm which is very promising for designing high power SC fiber laser sources in the mid-IR atmospheric windows and the molecular fingerprint region.

  6. Improved photon counting efficiency calibration using superconducting single photon detectors

    NASA Astrophysics Data System (ADS)

    Gan, Haiyong; Xu, Nan; Li, Jianwei; Sun, Ruoduan; Feng, Guojin; Wang, Yanfei; Ma, Chong; Lin, Yandong; Zhang, Labao; Kang, Lin; Chen, Jian; Wu, Peiheng

    2015-10-01

    The quantum efficiency of photon counters can be measured with standard uncertainty below 1% level using correlated photon pairs generated through spontaneous parametric down-conversion process. Normally a laser in UV, blue or green wavelength range with sufficient photon energy is applied to produce energy and momentum conserved photon pairs in two channels with desired wavelengths for calibration. One channel is used as the heralding trigger, and the other is used for the calibration of the detector under test. A superconducting nanowire single photon detector with advantages such as high photon counting speed (<20 MHz), low dark count rate (<50 counts per second), and wideband responsivity (UV to near infrared) is used as the trigger detector, enabling correlated photons calibration capabilities into shortwave visible range. For a 355nm single longitudinal mode pump laser, when a superconducting nanowire single photon detector is used as the trigger detector at 1064nm and 1560nm in the near infrared range, the photon counting efficiency calibration capabilities can be realized at 532nm and 460nm. The quantum efficiency measurement on photon counters such as photomultiplier tubes and avalanche photodiodes can be then further extended in a wide wavelength range (e.g. 400-1000nm) using a flat spectral photon flux source to meet the calibration demands in cutting edge low light applications such as time resolved fluorescence and nonlinear optical spectroscopy, super resolution microscopy, deep space observation, and so on.

  7. Infrared spectrally selective low emissivity from Ge/ZnS one-dimensional heterostructure photonic crystal

    NASA Astrophysics Data System (ADS)

    Zhang, Weigang; Xu, Guoyue; Zhang, Jianchao; Wang, Huihui; Hou, Haili

    2014-11-01

    Ge/ZnS one-dimensional heterostructure photonic crystal (1DHPC) was successfully prepared by alternating thin films of Ge and ZnS on the quartz substrate by using the optical coating technology. The microstructure and spectral emissivity of as-prepared 1DHPC were characterized by using scanning electron microscopy (SEM) and fourier transform infrared spectrometer (FTIR), respectively. The test result of spectral emissivity shows that the average emissivities of as-prepared Ge/ZnS 1DHPC in the atmospheric windows of 3-5 μm and 8-14 μm can be as low as 0.046 and 0.190, respectively, but the average emissivity in the non-atmospheric window of 5-8 μm can be as high as 0.579. The results indicate that the as-prepared Ge/ZnS 1DHPC has obviously infrared spectrally selective low emissivity characteristic, basically meets the requirements of our design. The as-prepared 1DHPC with infrared spectrally selective low emissivity is promising for use as a material to unify the infrared stealth and effective cooling of the aircraft.

  8. GaAs cryogenic readout electronics for high impedance detector arrays for far-infrared and submillimeter wavelength region

    NASA Astrophysics Data System (ADS)

    Nagata, H.; Matsuo, H.; Hibi, Y.; Kobayashi, J.; Nakahashi, M.; Ikeda, H.; Fujiwara, M.

    2009-11-01

    We have been developing cryogenic readout integrate circuits (ROICs) for high impedance submillimeter and far-infrared detectors: Our ROICs are constructed from SONY GaAs-JFETs, which have excellent performance even at less than 1 K. We designed ROICs consisting of analog readouts and digital circuits for 32-element SIS photon detectors fabricated in RIKEN. The analog readout is ac-coupled capacitive transimpedance amplifier (CTIA), which is composed of the two-stage amplifier. Some initial test results of the ac-coupled CTIA gave us the following performance; open loop gain of >740, power consumption ≈1.4 μW. The input referred noise is ≈4 μV/ √{Hz} at 1 Hz. These results suggest that low power and high sensitive cryogenic readout electronics are successfully developed for high impedance detectors.

  9. Utilizing a silicon-photonic micro-ring-resonator and multi-ring scheme for wavelength-switchable erbium fiber laser in single-longitudinal-mode

    NASA Astrophysics Data System (ADS)

    Yeh, Chien-Hung; Hsu, Yung; Chow, Chi-Wai

    2016-06-01

    In this paper, a stable and wavelength-switchable silicon-photonic erbium-doped fiber (EDF) triple-ring laser is proposed and demonstrated. In the experiment, the integration of a silicon-on-insulator (SOI)-based grating coupler and silicon-micro-ring-resonator (SMRR) are coupled and connected to the proposed EDF triple-ring laser for generating wavelength. Here, the output wavelength can be adjusted in a wavelength range of 1529.8 –1561.8 nm with a 2.0 nm tuning step according to the free spectrum range (FSR) of the SMRR. Moreover, the stability performance of the output power and wavelength are also discussed and analyzed.

  10. Molecular beam epitaxy growth of peak wavelength-controlled InGaAs/AlGaAs quantum wells for 4.3-μm mid-wavelength infrared detection

    PubMed Central

    2013-01-01

    InGaAs/AlGaAs multiple quantum wells used for 4.3 μm mid-wavelength infrared quantum well infrared detectors were grown by molecular beam epitaxy. In composition loss was observed and quantitatively studied by high-resolution X-ray diffraction technology. By this In composition loss effect, the energy band engineering on the photo-response wavelength is not easily achieved. A thin AlGaAs barrier grown at low temperature is used to suppress the In atom desorption, and this growth process was verified to be able to adjust the photo-response wavelength as designed by energy band engineering in the photocurrent spectrum. PMID:23822825

  11. Development of long wavelength semiconductor diode lasers near 28 microns for use in infrared heterodyne spectrometers

    NASA Technical Reports Server (NTRS)

    Linden, K. J.

    1984-01-01

    The development of tunable diode lasers operating in the 28 micrometers spectral region for use in infrared heterodyne spectrometers is reported. A process capable of yielding lasers emitting 500 micron W of multimode power, 112 micron W in a true single mode and true single mode operation at laser currents of up to 35% above threshold was developed. Results were obtained from narrow mesastripe (20 micrometer wide) short cavity (120 micrometer length) laser configurations. Six stripe geometry lasers, with a variety of cavity widths and lengths were delivered. The techniques to fabricate such devices was obtained and the long term reliability of such lasers by reproducible electrical and optical output characteristics fabrication from lasers are demonstrated.

  12. A high-speed, four-wavelength infrared pyrometer for low temperature shock physics experiments

    SciTech Connect

    Seifter, A.; Boboridis, K.; Payton, J. R.; Obst, A. W.

    2004-01-01

    In addition to the standard problems associated with contactless temperature measurements, pyrometry in shock physics experiments has many additional concerns. These include background temperatures which are often higher than the substrate temperature, non-uniform sample temperature due to hotspots and ejecta, fast sample motion up to several km s{sup -1}, fast-changing sample emissivity at shock breakout, and very short measurement times. We have designed a four channel, high speed near-infrared (NIR) pyrometer for measurements in the 400 to 1000K blackbody temperature regime. The front end optics are specific to each experiment, utilizing preferably reflective optics in order to mitigate spectral dispersion. Next-generation instruments under development are also discussed.

  13. Short-Wavelength Infrared (SWIR) spectroscopy of low-grade metamorphic volcanic rocks of the Pilbara Craton

    NASA Astrophysics Data System (ADS)

    Abweny, Mohammad S.; van Ruitenbeek, Frank J. A.; de Smeth, Boudewijn; Woldai, Tsehaie; van der Meer, Freek D.; Cudahy, Thomas; Zegers, Tanja; Blom, Jan-Kees; Thuss, Barbara

    2016-05-01

    This paper shows the results of Short-Wavelength Infrared (SWIR) spectroscopy investigations of volcanic rocks sampled from low-grade metamorphic greenstone belts of the Archean Pilbara Craton in Western Australia. From the reflectance spectra a range of spectrally active minerals were identified, including chlorites, hornblende, actinolite, epidote and white micas. The rock samples were grouped into mineral assemblages based on their spectrally identified minerals and stratigraphic positions. The metamorphic amphibolite and greenschist facies could be identified from the SWIR spectroscopic data as well as three sub zones of the greenschist facies: 1) a zone containing Fe-chlorite; 2) a zone containing intermediate chlorite and epidote; and 3) a zone containing intermediate chlorite, actinolite and hornblende. Spectral parameters were calculated from the reflectance spectra to assess the metamorphic grade and zones. Plots of the depth parameters of the Fe-OH feature near 2250 nm versus the Mg-OH feature near 2390 nm differentiate the metamorphic amphibolite and greenschist facies and a transition zone between the two. The wavelength position parameter of the Mg-OH absorption feature near 2340 nm also serves to discriminate between the various metamorphic sub zones. The identification of the metamorphic grades of the volcanic sequences in greenstone belts with SWIR spectroscopy is useful for regional geological field studies, exploration for metamorphic mineral deposits hosted in the greenstone belts and the interpretation of hyperspectral remote sensing data sets covering similar types of terranes.

  14. Photoacoustic imaging of a near-infrared fluorescent marker based on dual wavelength pump-probe excitation

    NASA Astrophysics Data System (ADS)

    Märk, Julia; Theiss, Christoph; Schmitt, Franz-Josef; Laufer, Jan

    2014-03-01

    Photoacoustic imaging has been used to determine the spatial distribution of fluorophores, such as exogenous dyes and genetically expressed proteins, from images acquired in phantoms and in vivo. Most methods involve the acquisition of multiwavelength images and rely on differences in the absorption spectra of the tissue chromophores to estimate the spatial distribution and abundance of the latter using spectral decomposition techniques, such as model based inversion schemes. However, the inversion of 3-D images can be computationally expensive. Experimental approaches to localising contrast agents may therefore be useful, especially if quantification is not essential. This work aims to develop a method for determining the spatial distribution of a near-infrared fluorescent cell marker from images acquired using dual wavelength excitation. The excitation wavelengths coincided with the absorption and emission spectrum of the fluorophore. The contrast mechanism relies on reducing the excited state lifetime of the fluorophore by inducing stimulated emission. This changes the amount of energy thermalized by the fluorophore, and hence the photoacoustic signal amplitude. Since this is not observed in endogenous chromophores, the background may be removed by subtracting two images acquired with and without pulse delay between the pump and probe pulses. To characterise the fluorophore, the signal amplitude is measured in a cuvette as a function of pulse delay, concentration, and fluence. The spatial distribution of the fluorophore is determined from images acquired in realistic tissue phantoms. This method may be suitable for in vivo applications, such as imaging of exogenous or genetically expressed fluorescent cell markers.

  15. Low-cost tissue simulating phantoms with adjustable wavelength-dependent scattering properties in the visible and infrared ranges

    NASA Astrophysics Data System (ADS)

    Saager, Rolf B.; Quach, Alan; Rowland, Rebecca A.; Baldado, Melissa L.; Durkin, Anthony J.

    2016-06-01

    We present a method for low-cost fabrication of polydimethylsiloxane (PDMS) tissue simulating phantoms with tunable scattering spectra, spanning visible, and near-infrared regimes. These phantoms use optical polishing agents (aluminum oxide powders) at various grit sizes to approximate in vivo tissue scattering particles across multiple size distributions (range: 17 to 3 μm). This class of tunable scattering phantoms is used to mimic distinct changes in wavelength-dependent scattering properties observed in tissue pathologies such as partial thickness burns. Described by a power-law dependence on wavelength, the scattering magnitude of these phantoms scale linearly with particle concentration over a physiologic range [μs‧=(0.5 to 2.0 mm-1)] whereas the scattering spectra, specific to each particle size distribution, correlate to distinct exponential coefficients (range: 0.007 to 0.32). Aluminum oxide powders used in this investigation did not detectably contribute to the absorption properties of these phantoms. The optical properties of these phantoms are verified through inverse adding-doubling methods and the tolerances of this fabrication method are discussed.

  16. Short-Wavelength Infrared (SWIR) spectroscopy of low-grade metamorphic volcanic rocks of the Pilbara Craton

    NASA Astrophysics Data System (ADS)

    Abweny, Mohammad S.; van Ruitenbeek, Frank J. A.; de Smeth, Boudewijn; Woldai, Tsehaie; van der Meer, Freek D.; Cudahy, Thomas; Zegers, Tanja; Blom, Jan-Kees; Thuss, Barbara

    2016-05-01

    This paper shows the results of Short-Wavelength Infrared (SWIR) spectroscopy investigations of volcanic rocks sampled from low-grade metamorphic greenstone belts of the Archean Pilbara Craton in Western Australia. From the reflectance spectra a range of spectrally active minerals were identified, including chlorites, hornblende, actinolite, epidote and white micas. The rock samples were grouped into mineral assemblages based on their spectrally identified minerals and stratigraphic positions. The metamorphic amphibolite and greenschist facies could be identified from the SWIR spectroscopic data as well as three sub zones of the greenschist facies: 1) a zone containing Fe-chlorite; 2) a zone containing intermediate chlorite and epidote; and 3) a zone containing intermediate chlorite, actinolite and hornblende. Spectral parameters were calculated from the reflectance spectra to assess the metamorphic grade and zones. Plots of the depth parameters of the Fe-OH feature near 2250 nm versus the Mg-OH feature near 2390 nm differentiate the metamorphic amphibolite and greenschist facies and a transition zone between the two. The wavelength position parameter of the Mg-OH absorption feature near 2340 nm also serves to discriminate between the various metamorphic sub zones. The identification of the metamorphic grades of the volcanic sequences in greenstone belts with SWIR spectroscopy is useful for regional geological field studies, exploration for metamorphic mineral deposits hosted in the greenstone belts and the interpretation of hyperspectral remote sensing data sets covering similar types of terranes.

  17. A near-infrared methane detection system using a 1.654 μm wavelength-modulated diode laser

    NASA Astrophysics Data System (ADS)

    Fu, Yang; Liu, Hui-fang; Sui, Yue; Li, Bin; Ye, Wei-lin; Zheng, Chuan-tao; Wang, Yi-ding

    2016-03-01

    By adopting a distributed feedback laser (DFBL) centered at 1.654 μm, a near-infrared (NIR) methane (CH4) detection system based on tunable diode laser absorption spectroscopy (TDLAS) is experimentally demonstrated. A laser temperature control as well as wavelength modulation module is developed to control the laser's operation temperature. The laser's temperature fluctuation can be limited within the range of -0.02—0.02 °C, and the laser's emitting wavelength varies linearly with the temperature and injection current. An open reflective gas sensing probe is realized to double the absorption optical path length from 0.2 m to 0.4 m. Within the detection range of 0—0.01, gas detection experiments were conducted to derive the relation between harmonic amplitude and gas concentration. Based on the Allan deviation at an integral time of 1 s, the limit of detection ( LoD) is decided to be 2.952×10-5 with a path length of 0.4 m, indicating a minimum detectable column density of ~1.2×10-5 m. Compared with our previously reported NIR CH4 detection system, this system exhibits some improvement in both optical and electrical structures, including the analogue temperature controller with less software consumption, simple and reliable open reflective sensing probe.

  18. Integration of wavelength signal divider and infrared photodetectors based on the plasma dispersion effect in SiGe/Si

    NASA Astrophysics Data System (ADS)

    Li, Baojun; Jiang, Zuimin; Pei, Chengwen; Qin, Jie; Wang, Xun; Li, Guozheng; Wan, Jianjun; Liu, Enke

    1999-03-01

    Based on the plasma dispersion effect, a single-mode SiGe wavelength signal divider (WSD) integrated with infrared photodetectors for optical communication at the wavelengths of 1.3 and 1.55 μm is proposed and fabricated by molecular beam epitaxy. The device performances are measured. The crosstalks of the WSD at a forward modulation bias of 1.2 V are -25 and -18 dB at 1.3 and 1.55 μm, respectively. The insertion losses are 2.01 and 2.64 dB for 1.3 and 1.55 μm, respectively. At -5 V reverse bias, the dark currents of the detectors at the 1.3 and 1.55 μm output branches are 45 and 64 nA, respectively. Photocurrent responsivities of 0.08 and 0.07 A/W for the two detectors at the 1.3 and 1.55 μm output branches have been achieved. The quantum efficiencies of the whole WSD and detector integration system are estimated to be about 19% and 18.2% for the 1.3 and 1.55 μm output branches, respectively.

  19. First-Light Galaxies or Intrahalo Stars: Multi-Wavelength Measurements of the Infrared Background Anisotropies

    NASA Astrophysics Data System (ADS)

    Cooray, Asantha

    The research program described in this proposal can be broadly described as data analysis, measurement, and interpretation of the spatial fluctuations of the unresolved cosmic IR background. We will focus primarily on the background at optical and near-IR wavelengths as probed by Hubble and Spitzer. As absolute background intensity measurements are challenging, the focus is on the spatial fluctuations similar to the anisotropiesof the cosmic microwave background (CMB). Measurements of the unresolved Spitzer fluctuations by two independent teams on multiple fields agree within the measurement errors. However, there are now two interpretations on the origin of the unresolved IRAC fluctuations. One involves a population of faint sources at very high redshifts (z > 6) during the epoch of reionization. The second interpretation involves the integrated emission from intrahalo light associated with diffuse stars in the outskirts of z of 1 to 3 dark matter halos of galaxies. We now propose to further test these two interpretations with a new set of measurements at shorter IR and optical wavelengths with HST/ACS and WFC3 overlapping with deep IRAC surveys. A multi-wavelength study from 0.5 to 4.5 micron will allow us to independently determine the relative contribution of intrahalo light and z > 8 faint galaxies to the unresolved IR fluctuations. We will also place strong limits on the surface density of faint sources at z > 8. Such a limit will be useful for planning deep surveys with JWST. Moving to the recent wide IRAC fields with the warm mission, we propose to study fluctuations at tens of degree angular scales. At such large angular scales IRAC fluctuations should trace diffuse Galactic light (DGL), ISM dust-scattered starlight in our Galaxy. We will measure the amplitude and slope of the DGL power spectrum and compare them to measurements of the Galactic dust power spectrum from IRAS and Planck and study if the large degree-scale fluctuations seen in CIBER can be

  20. Design and fabrication of diffraction grating for application in hyperspectral imaging for the long-wavelength infrared spectral region

    NASA Astrophysics Data System (ADS)

    Vojtíšek, Petr; Possolt, Martin; Doleček, Roman; Steiger, Kateřina; Pintr, Pavel; Václavík, Jan

    2015-01-01

    Hyperspectral imaging as an instrument for obtaining a wide range of information on the world around us is a fast developing area of modern technology. In such systems, the desired information is obtained via the processing of stored spectral information of a measured scene. One of the main advantages of hyperspectral imaging over conventional imaging methods is the use of a broad spectral range, which is not restricted to just the visible range but can extend to adjacent regions and further, for example, deeply into the infrared region. The main element in such hyperspectral systems is the spectral separating system, which can be based on a wide variety of spectral dependent physical processes - birefringence, refraction, diffraction, etc. In this contribution, we would like to present the design and fabrication process of such a spectral separating system based on diffraction grating. The main requirements for this system were - operation in the long-wavelength infrared region (LWIR, 7-14 um), the highest possible diffraction efficiency in this spectral region with respect to the black body radiation of a temperature of 350 K, and the avoidance of restrictions inherent to fabrication. The design was carried out with the use of Scalar theory of transmission gratings, which is based on the idea of thin grating. The obtained results were compared to the designs produced via the Rigorous coupled wave theory (RCWA) and Finite Element Method (FEM). Fabrication of the designed grating was done in germanium with the use of single-point diamond turning.

  1. Low-dark current p-on-n MCT detector in long and very long-wavelength infrared

    NASA Astrophysics Data System (ADS)

    Cervera, C.; Baier, N.; Gravrand, O.; Mollard, L.; Lobre, C.; Destefanis, G.; Zanatta, J. P.; Boulade, O.; Moreau, V.

    2015-06-01

    This paper presents recent developments done at CEA-LETI Infrared Laboratory on processing and characterization of p-on-n HgCdTe (MCT) planar infrared focal plane arrays (FPAs) in LWIR and VLWIR spectral bands. These FPAs have been grown using liquid phase epitaxy (LPE) on a lattice matched CdZnTe substrate. This technology presents lower dark current and lower serial resistance in comparison with n-on-p vacancy doped architecture and is well adapted for low flux detection or high operating temperature. This architecture has been evaluated for space applications in LWIR and VLWIR spectral bands with cutoff wavelengths from 10μμm up to 17μm at 78K. Innovations have been introduced to the technological process to form a heterojunction with a LPE growth technique. The aim was to lower dark current at low temperature, by decreasing currents from the depletion region. Electro-optical characterizations on p-on-n photodiodes have been performed on QVGA format FPAs with 30μm pixel pitches. Results show excellent operabilities in current and responsivity, with low dispersion and noise limited by current shot-noise. Studies performed on dark current show that dark current densities are consistent with the heuristic prediction law "Rule07" at 78K. Below this temperature, dark current varies as a pure diffusion current.

  2. Surface mineral mapping at Virginia City and Steamboat Springs, Nevada with multi-wavelength infrared remote sensing image data

    NASA Astrophysics Data System (ADS)

    Vaughan, R. Greg

    The purpose of this study was to use a combination of high spatial resolution airborne visible, near infrared, short wave infrared (VNIR/SWIR) and thermal infrared (TIR) image data to remotely identify and map exposed alteration minerals around both active and ancient hydrothermal systems, and the mineral by-products of weathered mine tailings. Three case study areas were evaluated: (1) Steamboat Springs, as an active geothermal system; (2) Geiger Grade and Virginia City, as ancient hydrothermal systems; and (3) Virginia City, as a historic mining district. Remote sensing data from the Airborne Visible Infrared Imaging Spectrometer (AVIRIS), as well as data from newly developed airborne imaging spectrometers: SpecTIR Corporation's airborne hyperspectral imager (HyperSpecTIR), the MODIS-ASTER airborne simulator (MASTER), and the Spatially Enhanced Broadband Array Spectrograph System (SEBASS) were acquired and processed into mineral maps based on the unique spectral signatures of image pixels. VNIR/SWIR and TIR field spectrometer data were collected for both calibration and validation of the remote data sets, and field sampling, laboratory spectral analyses and XRD analyses were made to corroborate the surface mineralogy identified by spectroscopic methods. In all of the case study areas the minerals mapped included sinter, quartz/chalcedony, albite, calcite, dolomite, hydrous sulfate minerals (tamarugite, alunogen, gypsum and hexahydrite), jarosite, hematite, goethite, alunite, pyrophyllite, kaolinite, montmorillonite/muscovite, and chlorite. The results were synthesized into single thematic mineral maps and indicate that the combination of multi-channel infrared remote sensing data is an effective technique for the unique identification and mapping of weathering and alteration minerals that are characteristic of active and fossil hydrothermal systems, as well as acid mine drainage potential. This study provides many examples of the advantages of high spatial and

  3. Improving Brush Polymer Infrared One-Dimensional Photonic Crystals via Linear Polymer Additives

    SciTech Connect

    Macfarlane, Robert J.; Kim, Bongkeun; Lee, Byeongdu; Weitekamp, Raymond A.; Bates, Christopher M.; Lee, Siu Fung; Chang, Alice B.; Delaney, Kris T.; Fredrickson, Glen H.; Atwater, Harry A.; Grubbs, Robert H.

    2014-12-17

    Brush block copolymers (BBCPs) enable the rapid fabrication of self-assembled one-dimensional photonic crystals with photonic band gaps that are tunable in the UV-vis-IR, where the peak wavelength of reflection scales with the molecular weight of the BBCPs. Due to the difficulty in synthesizing very large BBCPs, the fidelity of the assembled lamellar nanostructures drastically erodes as the domains become large enough to reflect IR light, severely limiting their performance as optical filters. To overcome this challenge, short linear homopolymers are used to swell the arrays to ~180% of the initial domain spacing, allowing for photonic band gaps up to~1410 nm without significant opacity in the visible, demonstrating improved ordering of the arrays. Additionally, blending BBCPs with random copolymers enables functional groups to be incorporated into the BBCP array without attaching them directly to the BBCPs. The addition of short linear polymers to the BBCP arrays thus offers a facile means of improving the self-assembly and optical properties of these materials, as well as adding a route to achieving films with greater functionality and tailorability, without the need to develop or optimize the processing conditions for each new brush polymer synthesized.

  4. A demonstration of the simple optical fiber filter in visible and near-infrared wavelengths from green laser and red laser pointers

    NASA Astrophysics Data System (ADS)

    Talataisong, W.; Chitaree, R.; Arayathanitkul, K.

    2015-07-01

    The optical fiber filter can be used to reject the noise or unwanted spectrum in the optical communication system. In this study, the performance of the optical fiber filter in visible and near-infrared wavelengths is studied. The working principle of the filter is based on the cladding mode coupling to the high order mode introduced by perturbation on a short section of single-mode (SM) fiber with a specific cut-off wavelength. In the previous study, the filtered wavelengths from the SM-fibers with the cut-off wavelength of 600 nm are 547 nm and near IR range (980-1,100 nm). The filtered wavelength from the SM-fiber with the cut-off wavelength of 800 nm is 666 nm. Also, the magnitude of the filtered wavelengths can be controlled by the magnitude of the applied perturbation force. In this study, the green solid state laser with the wavelength of 532 nm (2nd harmonic component), 808 nm (pump wavelength), and 1,064 nm (fundamental component) and the red diode laser with the wavelength of 668 nm are launched into the SM-fiber with the cut-off wavelength of 600 and 800 nm, respectively. The experimental results clearly show that the harmonic wavelength of 1,064 nm of green laser can be filtered out by the fiber with cut-off wavelength of 600 nm up to 66% with the perturbation force 60 N. The fiber with cut-off wavelength of 800 nm can reject the red laser spectrum up to 50% with the perturbation force 80 N.

  5. Radiative transfer model for aerosols at infrared wavelengths for passive remote sensing applications: revisited.

    PubMed

    Ben-David, Avishai; Davidson, Charles E; Embury, Janon F

    2008-11-01

    We introduced a two-dimensional radiative transfer model for aerosols in the thermal infrared [Appl. Opt.45, 6860-6875 (2006)APOPAI0003-693510.1364/AO.45.006860]. In that paper we superimposed two orthogonal plane-parallel layers to compute the radiance due to a two-dimensional (2D) rectangular aerosol cloud. In this paper we revisit the model and correct an error in the interaction of the two layers. We derive new expressions relating to the signal content of the radiance from an aerosol cloud based on the concept of five directional thermal contrasts: four for the 2D diffuse radiance and one for direct radiance along the line of sight. The new expressions give additional insight on the radiative transfer processes within the cloud. Simulations for Bacillus subtilis var. niger (BG) bioaerosol and dustlike kaolin aerosol clouds are compared and contrasted for two geometries: an airborne sensor looking down and a ground-based sensor looking up. Simulation results suggest that aerosol cloud detection from an airborne platform may be more challenging than for a ground-based sensor and that the detection of an aerosol cloud in emission mode (negative direct thermal contrast) is not the same as the detection of an aerosol cloud in absorption mode (positive direct thermal contrast). PMID:19122735

  6. Radiative transfer model for aerosols in infrared wavelengths for passive remote sensing applications.

    PubMed

    Ben-David, Avishai; Embury, Janon F; Davidson, Charles E

    2006-09-10

    A comprehensive analytical radiative transfer model for isothermal aerosols and vapors for passive infrared remote sensing applications (ground-based and airborne sensors) has been developed. The theoretical model illustrates the qualitative difference between an aerosol cloud and a chemical vapor cloud. The model is based on two and two/four stream approximations and includes thermal emission-absorption by the aerosols; scattering of diffused sky radiances incident from all sides on the aerosols (downwelling, upwelling, left, and right); and scattering of aerosol thermal emission. The model uses moderate resolution transmittance ambient atmospheric radiances as boundary conditions and provides analytical expressions for the information on the aerosol cloud that is contained in remote sensing measurements by using thermal contrasts between the aerosols and diffused sky radiances. Simulated measurements of a ground-based sensor viewing Bacillus subtilis var. niger bioaerosols and kaolin aerosols are given and discussed to illustrate the differences between a vapor-only model (i.e., only emission-absorption effects) and a complete model that adds aerosol scattering effects. PMID:16926922

  7. Cryogenic infrared filter made of alumina for use at millimeter wavelength.

    PubMed

    Inoue, Yuki; Matsumura, Tomotake; Hazumi, Masashi; Lee, Adrian T; Okamura, Takahiro; Suzuki, Aritoki; Tomaru, Takayuki; Yamaguchi, Hiroshi

    2014-03-20

    We propose a high-thermal-conductivity infrared filter using alumina for millimeter-wave detection systems. We constructed a prototype two-layer antireflection-coated alumina filter with a diameter of 100 mm and a thickness of 2 mm and characterized its thermal and optical properties. The transmittance of this filter at 95 and 150 GHz is 97% and 95%, respectively, while the estimated 3 dB cut-off frequency is at 450 GHz. The high thermal conductivity of alumina minimizes thermal gradients. We measure a differential temperature of only 0.21 K between the center and the edge of the filter when it is mounted on a thermal anchor of 77 K. We also constructed a thermal model based on the prototype filter and analyzed the scalability of the filter diameter. We conclude that the temperature increase at the center of the alumina IR filter is less than 6 K, even with a large diameter of 500 mm, when the temperature at the edge of the filter is 50 K. This is suitable for an application to a large-throughput next-generation cosmic-microwave-background polarization experiment such as POLARBEAR-2. PMID:24663447

  8. High sensitivity of middle-wavelength infrared photodetectors based on an individual InSb nanowire

    PubMed Central

    2013-01-01

    Single-crystal indium antimony (InSb) nanowire was fabricated into middle-infrared photodetectors based on a metal–semiconductor-metal (M-S-M) structure. The InSb nanowires were synthesized using an electrochemical method at room temperature. The characteristics of the FET reveal an electron concentration of 3.6 × 1017 cm−3 and an electron mobility of 215.25 cm2 V−1 s−1. The photodetectors exhibit good photoconductive performance, excellent stability, reproducibility, superior responsivity (8.4 × 104 A W−1), and quantum efficiency (1.96 × 106%). These superior properties are attributed to the high surface-to-volume ratio and single-crystal 1D nanostructure of photodetectors that significantly reduce the scattering, trapping, and the transit time between the electrodes during the transport process. Furthermore, the M-S-M structure can effectively enhance space charge effect by the formation of the Schottky contacts, which significantly assists with the electron injection and photocurrent gain. PMID:23866944

  9. The Unexpectedly Bright Comet C/2012 F6 (Lemmon) Unveiled at Near-infrared Wavelengths

    NASA Astrophysics Data System (ADS)

    Paganini, Lucas; DiSanti, Michael A.; Mumma, Michael J.; Villanueva, Geronimo L.; Bonev, Boncho P.; Keane, Jacqueline V.; Gibb, Erika L.; Boehnhardt, Hermann; Meech, Karen J.

    2014-01-01

    We acquired near-infrared spectra of the Oort cloud comet C/2012 F6 (Lemmon) at three different heliocentric distances (R h) during the comet's 2013 perihelion passage, providing a comprehensive measure of the outgassing behavior of parent volatiles and cosmogonic indicators. Our observations were performed pre-perihelion at R h = 1.2 AU with CRIRES (on 2013 February 2 and 4), and post-perihelion at R h = 0.75 AU with CSHELL (on March 31 and April 1) and R h = 1.74 AU with NIRSPEC (on June 20). We detected 10 volatile species (H2O, OH* prompt emission, C2H6, CH3OH, H2CO, HCN, CO, CH4, NH3, and NH2), and obtained upper limits for two others (C2H2 and HDO). One-dimensional spatial profiles displayed different distributions for some volatiles, confirming either the existence of polar and apolar ices, or of chemically distinct active vents in the nucleus. The ortho-para ratio for water was 3.31 ± 0.33 (weighted mean of CRIRES and NIRSPEC results), implying a spin temperature >37 K at the 95% confidence limit. Our (3σ) upper limit for HDO corresponds to D/H < 2.45 × 10-3 (i.e., <16 Vienna Standard Mean Ocean Water, VSMOW). At R h = 1.2 AU (CRIRES), the production rate for water was Q(H2O) = 1.9 ± 0.1 × 1029 s-1 and its rotational temperature was T rot ~ 69 K. At R h = 0.75 AU (CSHELL), we measured Q(H2O) = 4.6 ± 0.6 × 1029 s-1 and T rot = 80 K on March 31, and 6.6 ± 0.9 × 1029 s-1 and T rot = 100 K on April 1. At R h = 1.74 AU (NIRSPEC), we obtained Q(H2O) = 1.1 ± 0.1 × 1029 s-1 and T rot ~ 50 K. The measured volatile abundance ratios classify comet C/2012 F6 as rather depleted in C2H6 and CH3OH, while HCN, CH4, and CO displayed abundances close to their median values found among comets. H2CO was the only volatile showing a relative enhancement. The relative paucity of C2H6 and CH3OH (with respect to H2O) suggests formation within warm regions of the nebula. However, the normal abundance of HCN and hypervolatiles CH4 and CO, and the enhancement of H2CO, may

  10. Mapping of Ozone on Mars at Infrared Wavelengths Using Crires at VLT

    NASA Astrophysics Data System (ADS)

    Radeva, Y. L.; Mumma, M. J.; Villanueva, G.; Novak, R.; Hartogh, P.; Encrenaz, T.; Kaufl, H.; Smette, A.

    2010-12-01

    We present spatially resolved maps of ozone and water on Mars, acquired on 21 August 2009 using the ultra-high resolution infrared spectrometer CRIRES at ESO’s VLT (Paranal, Chile). On Mars, the season was mid-summer in the South (Ls = 325) and the latitudinal resolution was 10 degrees FWHM at disk center. Ozone is produced by recombination of photochemically produced O and O2. It is destroyed by UV photolysis (with O2 (a1Dg) as a principal product) but also by reaction with odd hydrogen species (especially, H - a product of H2O vapor photolysis). Thus, simultaneous measurements of water and ozone can test this relationship. We quantified ozone using spectral lines (near 1.27 mm) of O2 (a1Dg). The emission from O2 (a1Dg) serves as a tracer for O3 above 20 km, since at lower altitudes collisions with CO2 quench the excited O2 (a1Dg) molecules. We confirmed the vertical location of the O2 (a1Dg) emission by extracting rotational temperatures from line-by-line ratios, and comparing them with standard vertical temperature profiles for this season and location(s). On the same night, we also obtained 2-D (lat-long) maps of Martian water from multiple H2O lines detected in the 3.3 mm region. We compare our retrieved distributions for ozone (latitude and altitude) with predictions of Lefevre et al. [I] based on their comprehensive 3-D circulation and photochemical model for the Martian atmosphere. Acknowledgements: This work was funded by NASA’s R&A Programs in Astrobiology (344-53-51), Planetary Astronomy (344-32-51-96), and Planetary Atmospheres (NNX09AB65G). We gratefully acknowledge the Director and staff of the European Southern Observatory, for supporting these observations. References: [I] Lefevre et al. (2004), J. of Geophys. Res. 109, E07004

  11. Collimated Blue and Infrared Beams Generated by Two-Photon Excitation in Rubidium Vapor

    NASA Astrophysics Data System (ADS)

    Gearba, Alina; Sell, Jerry; Olesen, Robert; Knize, Randy

    2016-05-01

    Utilizing nonlinear optical processes in Rb vapor we describe the generation of optical fields at 420 nm, 1.32 μm, and 1.37 μm. Input laser beams at 780 nm and 776 nm enter a heated Rb vapor cell collinear and circularly polarized. Rubidium atoms are excited to the 5D5 / 2 state, with blue light generated by four-wave mixing through the 6P3 / 2 --> 5S1 / 2 states, while infrared beams at 1.37 μm and 1.32 μm are generated by cascading decays through the 6S1 / 2 --> 5P3 / 2 and 6S1 / 2 --> 5P1 / 2 states, respectively. While the blue beam emission from four-wave mixing has been studied in detail, the mechanisms responsible for generating the infrared beams are still under investigation. We will present our results for the conditions which give rise to infrared beam generation by two-photon excitation in rubidium vapor.

  12. The Implications of M Dwarf Flares on the Detection and Characterization of Exoplanets at Infrared Wavelengths

    NASA Astrophysics Data System (ADS)

    Tofflemire, Benjamin M.; Wisniewski, John P.; Kowalski, Adam F.; Schmidt, Sarah J.; Kundurthy, Praveen; Hilton, Eric J.; Holtzman, Jon A.; Hawley, Suzanne L.

    2012-01-01

    We present the results of an observational campaign which obtained high-cadence, high-precision, simultaneous optical and IR photometric observations of three M dwarf flare stars for 47 hr. The campaign was designed to characterize the behavior of energetic flare events, which routinely occur on M dwarfs, at IR wavelengths to millimagnitude precision, and quantify to what extent such events might influence current and future efforts to detect and characterize extrasolar planets surrounding these stars. We detected and characterized four highly energetic optical flares having U-band total energies of ~7.8 × 1030 to ~1.3 × 1032 erg, and found no corresponding response in the J, H, or Ks bandpasses at the precision of our data. For active dM3e stars, we find that a ~1.3 × 1032 erg U-band flare (ΔU max ~ 1.5 mag) will induce <8.3 (J), <8.5 (H), and <11.7 (Ks) mmag of a response. A flare of this energy or greater should occur less than once per 18 hr. For active dM4.5e stars, we find that a ~5.1 × 1031 erg U-band flare (ΔU max ~ 1.6 mag) will induce <7.8 (J), <8.8 (H), and <5.1 (Ks) mmag of a response. A flare of this energy or greater should occur less than once per 10 hr. No evidence of stellar variability not associated with discrete flare events was observed at the level of ~3.9 mmag over 1 hr timescales and at the level of ~5.6 mmag over 7.5 hr timescales. We therefore demonstrate that most M dwarf stellar activity and flares will not influence IR detection and characterization studies of M dwarf exoplanets above the level of ~5-11 mmag, depending on the filter and spectral type. We speculate that the most energetic megaflares on M dwarfs, which occur at rates of once per month, are likely to be easily detected in IR observations with sensitivity of tens of millimagnitudes. We also discuss how recent detections of line flux enhancements during M dwarf flares could influence IR transmission spectroscopic observations of M dwarf exoplanets.

  13. Strong-field ionization of H{sub 2} from ultraviolet to near-infrared wavelengths: Photoelectron energy and angular identifications

    SciTech Connect

    Wilbois, Timo; Helm, Hanspeter

    2011-11-15

    Strong-field ionization of molecular hydrogen is studied at wavelengths ranging from 300 to 800 nm using pulses of 100-fs duration. We find that over this wide wavelength range, from nominally 4-photon to 11-photon ionization, resonance features dominate the ionization probability at intensities below 10{sup 14} W/cm{sup 2}. Photoelectron momentum maps recorded by an imaging spectrometer are analyzed to identify the wavelength-dependent ionization pathways in single ionization of molecular hydrogen. A number of models, some empirical, which are appropriate for a quantitative interpretation of the spectra and the ionization yield are introduced. A near-absolute comparison of measured ionization yields at 398 nm is made with the predictions based on a numerical solution [Y. V. Vanne and A. Saenz, Phys. Rev. A 79, 023421 (2009)] of the time-dependent Schroedinger equation for two correlated electrons.

  14. Two-photon, three-photon, and four-photon excellent near-infrared quantum cutting luminescence of Tm3+ ion activator emerged in Tm3+:YNbO4 powder phosphor one material simultaneously

    NASA Astrophysics Data System (ADS)

    Chen, Xiaobo; Salamo, Gregory J.; Li, Song; Wang, Jieliang; Guo, Yuying; Gao, Yan; He, Lizhu; Ma, Hui; Tao, Jingfu; Sun, Ping; Lin, Wei; Liu, Quanlin

    2015-12-01

    In present study, two-photon, three-photon, and four photon near-infrared quantum cutting luminescence of Tm3+ ion activator in YNbO4 powder phosphor is reported. The visible to near-infrared excitation and emission spectra and fluorescence lifetimes of Tm0.038Y0.962NbO4 powder phosphor are measured. Tm0.038Y0.962NbO4 is found to possess intense two-photon, strong three-photon, and moderate four-photon quantum cutting 1820 nm 3F4→3H6 luminescence of the Tm3+ ion simultaneously. The up-limit of the two-, three-, and four-photon near-infrared quantum cutting efficiency are found to be approximately 166%, 198%, and 192%, respectively. These results are expected to be valuable in aiding the probing of new generation environmentally friendly germanium Ge solar cells, currently a popular condensed matter physical topic globally.

  15. The Unexpectedly Bright Comet C-2012 F6 (Lemmon) Unveiled at Near-Infrared Wavelengths

    NASA Technical Reports Server (NTRS)

    Paganini, Lucas; Disanti, Michael A.; Mumma, Michael J.; Villanueva, Geronimo L.; Bonev, Boncho P.; Keane, Jacqueline V.; Gibb, Erika L.; Boehnhardt, Hermann; Meech, Karen J.

    2013-01-01

    We acquired near-infrared spectra of the Oort cloud comet C/2012 F6 (Lemmon) at three different heliocentric distances (R h) during the comet's 2013 perihelion passage, providing a comprehensive measure of the outgassing behavior of parent volatiles and cosmogonic indicators. Our observations were performed pre-perihelion at R h = 1.2 AU with CRIRES (on 2013 February 2 and 4), and post-perihelion at R h = 0.75 AU with CSHELL (on March 31 and April 1) and R h = 1.74 AU with NIRSPEC (on June 20). We detected 10 volatile species (H2O, OH* prompt emission, C2H6, CH3OH, H2CO, HCN, CO, CH4, NH3, and NH2), and obtained upper limits for two others (C2H2 and HDO). One-dimensional spatial profiles displayed different distributions for some volatiles, confirming either the existence of polar and apolar ices, or of chemically distinct active vents in the nucleus. The ortho-para ratio for water was 3.31 +/- 0.33 (weighted mean of CRIRES and NIRSPEC results), implying a spin temperature >37 K at the 95% confidence limit. Our (3s) upper limit for HDO corresponds to D/H < 2.45 × 10-3 (i.e., <16 Vienna Standard Mean Ocean Water, VSMOW). At R h = 1.2 AU (CRIRES), the production rate for water was Q(H2O) = 1.9 +/- 0.1 × 1029 s-1 and its rotational temperature was T rot 69 K. At R h = 0.75 AU (CSHELL), we measured Q(H2O) = 4.6 +/- 0.6 × 1029 s-1 and T rot = 80 K on March 31, and 6.6 +/- 0.9 × 1029 s-1 and T rot = 100 K on April 1. At R h = 1.74 AU (NIRSPEC), we obtained Q(H2O) = 1.1 +/- 0.1 × 1029 s-1 and T rot 50 K. The measured volatile abundance ratios classify comet C/2012 F6 as rather depleted in C2H6 and CH3OH, while HCN, CH4, and CO displayed abundances close to their median values found among comets. H2CO was the only volatile showing a relative enhancement. The relative paucity of C2H6 and CH3OH (with respect to H2O) suggests formation within warm regions of the nebula. However, the normal abundance of HCN and hypervolatiles CH4 and CO, and the enhancement of H2CO, may

  16. The unexpectedly bright comet C/2012 F6 (Lemmon) unveiled at near-infrared wavelengths

    SciTech Connect

    Paganini, Lucas; DiSanti, Michael A.; Mumma, Michael J.; Villanueva, Geronimo L.; Bonev, Boncho P.; Keane, Jacqueline V.; Meech, Karen J.; Gibb, Erika L.; Boehnhardt, Hermann

    2014-01-01

    We acquired near-infrared spectra of the Oort cloud comet C/2012 F6 (Lemmon) at three different heliocentric distances (R {sub h}) during the comet's 2013 perihelion passage, providing a comprehensive measure of the outgassing behavior of parent volatiles and cosmogonic indicators. Our observations were performed pre-perihelion at R {sub h} = 1.2 AU with CRIRES (on 2013 February 2 and 4), and post-perihelion at R {sub h} = 0.75 AU with CSHELL (on March 31 and April 1) and R {sub h} = 1.74 AU with NIRSPEC (on June 20). We detected 10 volatile species (H{sub 2}O, OH* prompt emission, C{sub 2}H{sub 6}, CH{sub 3}OH, H{sub 2}CO, HCN, CO, CH{sub 4}, NH{sub 3}, and NH{sub 2}), and obtained upper limits for two others (C{sub 2}H{sub 2} and HDO). One-dimensional spatial profiles displayed different distributions for some volatiles, confirming either the existence of polar and apolar ices, or of chemically distinct active vents in the nucleus. The ortho-para ratio for water was 3.31 ± 0.33 (weighted mean of CRIRES and NIRSPEC results), implying a spin temperature >37 K at the 95% confidence limit. Our (3σ) upper limit for HDO corresponds to D/H < 2.45 × 10{sup –3} (i.e., <16 Vienna Standard Mean Ocean Water, VSMOW). At R {sub h} = 1.2 AU (CRIRES), the production rate for water was Q(H{sub 2}O) = 1.9 ± 0.1 × 10{sup 29} s{sup –1} and its rotational temperature was T {sub rot} ∼ 69 K. At R {sub h} = 0.75 AU (CSHELL), we measured Q(H{sub 2}O) = 4.6 ± 0.6 × 10{sup 29} s{sup –1} and T {sub rot} = 80 K on March 31, and 6.6 ± 0.9 × 10{sup 29} s{sup –1} and T {sub rot} = 100 K on April 1. At R {sub h} = 1.74 AU (NIRSPEC), we obtained Q(H{sub 2}O) = 1.1 ± 0.1 × 10{sup 29} s{sup –1} and T {sub rot} ∼ 50 K. The measured volatile abundance ratios classify comet C/2012 F6 as rather depleted in C{sub 2}H{sub 6} and CH{sub 3}OH, while HCN, CH{sub 4}, and CO displayed abundances close to their median values found among comets. H{sub 2}CO was the only volatile showing

  17. Potential of the Thermal Infrared Wavelength Region to predict semi-arid Soil Surface Properties for Remote Sensing Monitoring

    NASA Astrophysics Data System (ADS)

    Eisele, Andreas; Chabrillat, Sabine; Lau, Ian; Hecker, Christoph; Hewson, Robert; Carter, Dan; Wheaton, Buddy; Ong, Cindy; Cudahy, Thomas John; Kaufmann, Hermann

    2014-05-01

    Digital soil mapping with the means of passive remote sensing basically relies on the soils' spectral characteristics and an appropriate atmospheric window, where electromagnetic radiation transmits without significant attenuation. Traditionally the atmospheric window in the solar-reflective wavelength region (visible, VIS: 0.4 - 0.7 μm; near infrared, NIR: 0.7 - 1.1 μm; shortwave infrared, SWIR: 1.1 - 2.5 μm) has been used to quantify soil surface properties. However, spectral characteristics of semi-arid soils, typically have a coarse quartz rich texture and iron coatings that can limit the prediction of soil surface properties. In this study we investigated the potential of the atmospheric window in the thermal wavelength region (long wave infrared, LWIR: 8 - 14 μm) to predict soil surface properties such as the grain size distribution (texture) and the organic carbon content (SOC) for coarse-textured soils from the Australian wheat belt region. This region suffers soil loss due to wind erosion processes and large scale monitoring techniques, such as remote sensing, is urgently required to observe the dynamic changes of such soil properties. The coarse textured sandy soils of the investigated area require methods, which can measure the special spectral response of the quartz dominated mineralogy with iron oxide enriched grain coatings. By comparison, the spectroscopy using the solar-reflective region has limitations to discriminate such arid soil mineralogy and associated coatings. Such monitoring is important for observing potential desertification trends associated with coarsening of topsoil texture and reduction in SOC. In this laboratory study we identified the relevant LWIR wavelengths to predict these soil surface properties. The results showed the ability of multivariate analyses methods (PLSR) to predict these soil properties from the soil's spectral signature, where the texture parameters (clay and sand content) could be predicted well in the models

  18. Specific local induction of DNA strand breaks by infrared multi-photon absorption

    PubMed Central

    Träutlein, D.; Deibler, M.; Leitenstorfer, A.; Ferrando-May, E.

    2010-01-01

    Highly confined DNA damage by femtosecond laser irradiation currently arises as a powerful tool to understand DNA repair in live cells as a function of space and time. However, the specificity with respect to damage type is limited. Here, we present an irradiation procedure based on a widely tunable Er/Yb : fiber femtosecond laser source that favors the formation of DNA strand breaks over that of UV photoproducts by more than one order of magnitude. We explain this selectivity with the different power dependence of the reactions generating strand breaks, mainly involving reactive radical intermediates, and the direct photochemical process leading to UV-photoproducts. Thus, localized multi-photon excitation with a wavelength longer than 1 µm allows for the selective production of DNA strand breaks at sub-micrometer spatial resolution in the absence of photosensitizers. PMID:19906733

  19. Si photonics expands to mid-wave and long-wave infrared: the fundamentals and applications

    NASA Astrophysics Data System (ADS)

    Malyutenko, V. K.

    2016-03-01

    In the absence of suitable methods for integrating III-V materials into standard microelectronic fabrication processes, Si has been actively explored as an alternative light emitter for silicon photonics. Although several proposals on how to increase the internal quantum efficiency of interband above bandgap (λ <=1μm) luminescence in this indirect bandgap material were successful and are becoming fruitful, the luminescence mode is not without pitfalls. These drawbacks are low emission power, temperature quenching, and the need for additional technological steps, like doping by emissive centers or fabrication of quantum-confined structures. Below, we describe an innovatively different approach for extracting light from Si at below-bandgap wavelengths (λ >>1μm) by making use of thermal emission from a bulk material. We also suggest several new optoelectronic devices operating in this unconventional mode.

  20. Near-Infrared Spectroscopy Using a Supercontinuum Laser: Application to Long Wavelength Transmission Spectra of Barley Endosperm and Oil.

    PubMed

    Ringsted, Tine; Dupont, Sune; Ramsay, Jacob; Jespersen, Birthe Møller; Sørensen, Klavs Martin; Keiding, Søren Rud; Engelsen, Søren Balling

    2016-07-01

    The supercontinuum laser is a new type of light source, which combines the collimation and intensity of a laser with the broad spectral region of a lamp. Using such a source therefore makes it possible to focus the light onto small sample areas without losing intensity and thus facilitate either rapid or high-intensity measurements. Single seed transmission analysis in the long wavelength (LW) near-infrared (NIR) region is one area that might benefit from a brighter light source such as the supercontinuum laser. This study is aimed at building an experimental spectrometer consisting of a supercontinuum laser source and a dispersive monochromator in order to investigate its capability to measure the barley endosperm using transmission experiments in the LW NIR region. So far, barley and wheat seeds have only been studied using NIR transmission in the short wavelength region up to 1100 nm. However, the region in the range of 2260-2380 nm has previously shown to be particularly useful in differentiating barley phenotypes using NIR spectroscopy in reflectance mode. In the present study, 350 seeds (consisting of 70 seeds from each of five barley genotypes) in 1 mm slices were measured by NIR transmission in the range of 2235-2381 nm and oils from the same five barley genotypes were measured in a cuvette with a 1 mm path length in the range of 2003-2497 nm. The spectra of the barley seeds could be classified according to genotypes by principal component analysis; and spectral covariances with reference analysis of moisture, β-glucan, starch, protein and lipid were established. The spectral variations of the barley oils were compared to the fatty acid compositions as measured using gas chromotography-mass spectrometry (GC-MS). PMID:27340221

  1. Calculation of the expected output spectrum for a mid-infrared supercontinuum source based on As ₂ S₃ chalcogenide photonic crystal fibers.

    PubMed

    Weiblen, R J; Docherty, A; Menyuk, C R; Shaw, L B; Sanghera, J S; Aggarwal, I D

    2014-09-01

    We computationally investigate supercontinuum generation in an As ₂ S₃ solid core photonic crystal fiber (PCF) with a hexagonal cladding of air holes. With a goal of obtaining a supercontinuum output spectrum that can predict what might be seen in an experiment, we investigate the spectral and statistical behavior of a mid-infrared supercontinuum source using a large ensemble average of 10⁶ realizations, in which the input pulse duration and energy vary. The output spectrum is sensitive to small changes (0.1%) in these pulse parameters. We show that the spectrum can be divided into three regions with distinct characteristics: a short-wavelength region with high correlation, a middle-wavelength region with minimal correlation, and a long-wavelength region where the behavior is dominated by a few rare large-bandwidth events. We show that statistically significant fluctuations exist in the experimentally expected output spectrum and that we can reproduce an excellent match to that spectrum with a converged shape and bandwidth using 5000 realizations. PMID:25321598

  2. Temperature-sensitive junction transformations for mid-wavelength HgCdTe photovoltaic infrared detector arrays by laser beam induced current microscope

    SciTech Connect

    Qiu, Weicheng; Hu, Weida Lin, Tie; Yin, Fei; Zhang, Bo; Chen, Xiaoshuang; Lu, Wei; Cheng, Xiang'ai Wang, Rui

    2014-11-10

    In this paper, we report on the disappearance of the photosensitive area extension effect and the unusual temperature dependence of junction transformation for mid-wavelength, n-on-p HgCdTe photovoltaic infrared detector arrays. The n-type region is formed by B{sup +} ion implantation on Hg-vacancy-doped p-type HgCdTe. Junction transformations under different temperatures are visually captured by a laser beam induced current microscope. A physical model of temperature dependence on junction transformation is proposed and demonstrated by using numerical simulations. It is shown that Hg-interstitial diffusion and temperature activated defects jointly lead to the p-n junction transformation dependence on temperature, and the weaker mixed conduction compared with long-wavelength HgCdTe photodiode contributes to the disappearance of the photosensitive area extension effect in mid-wavelength HgCdTe infrared detector arrays.

  3. Probing intermolecular couplings in liquid water with two-dimensional infrared photon echo spectroscopy

    NASA Astrophysics Data System (ADS)

    Paarmann, A.; Hayashi, T.; Mukamel, S.; Miller, R. J. D.

    2008-05-01

    Two-dimensional infrared photon echo and pump probe studies of the OH stretch vibration provide a sensitive probe of the correlations and couplings in the hydrogen bond network of liquid water. The nonlinear response is simulated using numerical integration of the Schrödinger equation with a Hamiltonian constructed to explicitly treat intermolecular coupling and nonadiabatic effects in the highly disordered singly and doubly excited vibrational exciton manifolds. The simulated two-dimensional spectra are in close agreement with our recent experimental results. The high sensitivity of the OH stretch vibration to the bath dynamics is found to arise from intramolecular mixing between states in the two-dimensional anharmonic OH stretch potential. Surprisingly small intermolecular couplings reproduce the experimentally observed intermolecular energy transfer times.

  4. Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide.

    PubMed

    Fuchs, F; Stender, B; Trupke, M; Simin, D; Pflaum, J; Dyakonov, V; Astakhov, G V

    2015-01-01

    Vacancy-related centres in silicon carbide are attracting growing attention because of their appealing optical and spin properties. These atomic-scale defects can be created using electron or neutron irradiation; however, their precise engineering has not been demonstrated yet. Here, silicon vacancies are generated in a nuclear reactor and their density is controlled over eight orders of magnitude within an accuracy down to a single vacancy level. An isolated silicon vacancy serves as a near-infrared photostable single-photon emitter, operating even at room temperature. The vacancy spins can be manipulated using an optically detected magnetic resonance technique, and we determine the transition rates and absorption cross-section, describing the intensity-dependent photophysics of these emitters. The on-demand engineering of optically active spins in technologically friendly materials is a crucial step toward implementation of both maser amplifiers, requiring high-density spin ensembles, and qubits based on single spins. PMID:26151881

  5. Massive Photons: An Infrared Regularization Scheme for Lattice QCD+QED.

    PubMed

    Endres, Michael G; Shindler, Andrea; Tiburzi, Brian C; Walker-Loud, André

    2016-08-12

    Standard methods for including electromagnetic interactions in lattice quantum chromodynamics calculations result in power-law finite-volume corrections to physical quantities. Removing these by extrapolation requires costly computations at multiple volumes. We introduce a photon mass to alternatively regulate the infrared, and rely on effective field theory to remove its unphysical effects. Electromagnetic modifications to the hadron spectrum are reliably estimated with a precision and cost comparable to conventional approaches that utilize multiple larger volumes. A significant overall cost advantage emerges when accounting for ensemble generation. The proposed method may benefit lattice calculations involving multiple charged hadrons, as well as quantum many-body computations with long-range Coulomb interactions. PMID:27563954

  6. Enhancing extraction efficiency of mid-infrared fluorescence in chalcogenide glass via photonic crystal

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Zhang, Peiqing; Ma, Beijiao; Dai, Shixun; Zhang, Wei; Nie, Qiuhua

    2016-04-01

    The use of rare earth-doped chalcogenide glass is an attractive method to develop mid-infrared sources. In this work, Er3+-doped chalcogenide glass is prepared, and photonic crystal (PC) pattern is designed to improve the extraction efficiency of light emission from the sample surface. The finite difference time domain simulation shows that the light extraction efficiency from the sample surface can be 1.62 times stronger than that from the sample without PC structure by introducing a simple two-dimensional (2D) PC structure into glass samples. This improvement was the result of the efficient light diffraction on the surface because of the integrated 2D PC. Results in this work offer a potential in developing midinfrared light sources.

  7. Two-photon-induced photoluminescence imaging of tumors using near-infrared excited gold nanoshells.

    PubMed

    Park, Jaesook; Estrada, Arnold; Sharp, Kelly; Sang, Krystina; Schwartz, Jon A; Smith, Danielle K; Coleman, Chris; Payne, J D; Korgel, Brian A; Dunn, Andrew K; Tunnell, James W

    2008-02-01

    Gold nanoshells (dielectric silica core/gold shell) are a novel class of hybrid metal nanoparticles whose unique optical properties have spawned new applications including more sensitive molecular assays and cancer therapy. We report a new photo-physical property of nanoshells (NS) whereby these particles glow brightly when excited by near-infrared light. We characterized the luminescence brightness of NS, comparing to that of gold nanorods (NR) and fluorescent beads (FB). We find that NS are as bright as NR and 140 times brighter than FB. To demonstrate the potential application of this bright two-photon-induced photoluminescence (TPIP) signal for biological imaging, we imaged the 3D distribution of gold nanoshells targeted to murine tumors. PMID:18542237

  8. Near-infrared photon time-of-flight spectroscopy of turbid materials up to 1400 nm.

    PubMed

    Svensson, Tomas; Alerstam, Erik; Khoptyar, Dmitry; Johansson, Jonas; Folestad, Staffan; Andersson-Engels, Stefan

    2009-06-01

    Photon time-of-flight spectroscopy (PTOFS) is a powerful tool for analysis of turbid materials. We have constructed a time-of-flight spectrometer based on a supercontinuum fiber laser, acousto-optical tunable filtering, and an InP/InGaAsP microchannel plate photomultiplier tube. The system is capable of performing PTOFS up to 1400 nm, and thus covers an important region for vibrational spectroscopy of solid samples. The development significantly increases the applicability of PTOFS for analysis of chemical content and physical properties of turbid media. The great value of the proposed approach is illustrated by revealing the distinct absorption features of turbid epoxy resin. Promising future applications of the approach are discussed, including quantitative assessment of pharmaceuticals, powder analysis, and calibration-free near-infrared spectroscopy. PMID:19566194

  9. Multiscale modeling of photon detectors from the infrared to the ultraviolet

    NASA Astrophysics Data System (ADS)

    Bellotti, Enrico; Schuster, Jonathan; Pinkie, Benjamin; Bertazzi, Francesco

    2013-09-01

    Due to the ever increasing complexity of novel semiconductor systems, it is essential to possess design tools and simulation strategies that include in the macroscopic device models the details of the microscopic physics and their dependence on the macroscopic (continuum) variables. Towards this end, we have developed robust multi-scale modeling capabilities that begin with modeling the intrinsic semiconductor properties. The models are fully capable of incorporating effects of substrate driven stress/strain and the material quality (dislocations and defects) on microscopic quantities such as the local transport coefficients and non-radiative recombination rate. Using this modeling approach we have extensively studied UV APD detectors and infrared focal plane arrays. Particular emphasis was placed on HgCdTe and InAsSb arrays incorporating photon trapping structures as well as two-color HgCdTe detectors arrays.

  10. Cascaded Mach-Zehnder wavelength filters in silicon photonics for low loss and flat pass-band WDM (de-)multiplexing.

    PubMed

    Horst, Folkert; Green, William M J; Assefa, Solomon; Shank, Steven M; Vlasov, Yurii A; Offrein, Bert Jan

    2013-05-20

    We present 1-to-8 wavelength (de-)multiplexer devices based on a binary tree of cascaded Mach-Zehnder-like lattice filters, and manufactured using a 90 nm CMOS-integrated silicon photonics technology. We demonstrate that these devices combine a flat pass-band over more than 50% of the channel spacing with low insertion loss of less than 1.6 dB, and have a small device size of approximately 500 × 400 µm. This makes this type of filters well suited for application as WDM (de-)multiplexer in silicon photonics transceivers for optical data communication in large scale computer systems. PMID:23736388

  11. Switchable dual-wavelength erbium-doped fiber laser based on the photonic crystal fiber loop mirror and chirped fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Chen, Wei-Guo; Lou, Shu-Qin; Wang, Li-Wen; Li, Hong-Lei; Guo, Tieying; Jian, Shui-Sheng

    2010-03-01

    The switchable dual-wavelength erbium-doped fiber laser (EDFL) with a two-mode photonic crystal fiber (PCF) loop mirror and a chirped fiber Bragg grating (CFBG) at room temperature is proposed and experimentally demonstrated. The two-mode PCF loop mirror is formed by inserting a piece of two-mode PCF into a Sagnac loop mirror, with the air-holes of the PCF intentionally collapsing at the splices. By adjusting the state of the polarization controller (PC) appropriately, the laser can be switched between the stable single- and dual-wavelength operations by means of the polarization hole burning (PHB) and spectral hole burning (SHB) effects.

  12. Aluminum nanopyramid array with tunable ultraviolet-visible-infrared wavelength plasmon resonances for rapid detection of carbohydrate antigen 199.

    PubMed

    Li, Wanbo; Qiu, Yongcai; Zhang, Li; Jiang, Lelun; Zhou, Zhangkai; Chen, Huanjun; Zhou, Jianhua

    2016-05-15

    Aluminum-based localized surface plasmon resonance (LSPR) holds attractive properties include low cost, high natural abundance, and ease of processing by a wide variety of methods including complementary metal oxide semiconductor process, making itself having an edge over conventional ones induced by noble metal. However, the inherent drawbacks of plasmonic mode limited on UV-green wavelength, low refractive index sensitivity, as well as heavy-shape-dependence greatly prevent aluminum plasmonics from real-life biosensing. Here, we demonstrated a uniform quasi-3-dimensional Al nanopyramid array (NPA) structure with tunable ultraviolet-visible-infrared (UV-vis-NIR) plasmon resonances for biosensing. By changing the reflection measuring angle, we could easily obtain typical peaks simultaneously exhibited on the reflectance spectrum across UV-vis-NIR wave region. The Al NPAs carried out high refractive index sensitivities which even comparable with that of noble metal, and can be used as a biosensor for directly detecting cytochrome c and carbohydrate antigen 199 in air after the sensing surface was washed cleanly and dried; the limits of detection were determined to be 800 nM and 29 ng/mL, respectively. Our proposed work therefore initiates the low-cost, high-performance biosensing using aluminum plasmonics, which would find wide applications in rapid diagnosis, mobile-healthcare and environmental monitoring. PMID:26748367

  13. Spectral absorptions on Phobos and Deimos in the visible/near infrared wavelengths and their compositional constraints

    NASA Astrophysics Data System (ADS)

    Fraeman, A. A.; Murchie, S. L.; Arvidson, R. E.; Clark, R. N.; Morris, R. V.; Rivkin, A. S.; Vilas, F.

    2014-02-01

    Absorption features on Phobos and Deimos in the visible/near infrared wavelength region (0.4-3.9 μm) are mapped using observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Fe2+ electronic absorptions diagnostic of olivine and pyroxene are not detected. A broad absorption centered around 0.65 μm within the red spectral units of both moons is detected, and this feature is also evident in telescopic, Pathfinder, and Phobos-2 observations of Phobos. A 2.8 μm metal-OH combination absorption on both moons is also detected in the CRISM data, and this absorption is shallower in the Phobos blue unit than in the Phobos red unit and Deimos. The strength, position, and shape of both of the 0.65 μm and 2.8 μm absorptions are similar to features seen on red-sloped, low-albedo primitive asteroids. Two end-member hypotheses are presented to explain the spectral features on Phobos and Deimos. The first invokes the presence of highly desiccated Fe-phyllosilicate minerals indigenous to the bodies, and the second invokes Rayleigh scattering and absorption of small iron particles formed by exogenic space weathering processing, coupled with implantation of H from solar wind. Both end-member hypotheses may play a role, and in situ exploration will be needed to ultimately determine the underlying causes for the pair of spectral features observed on Phobos and Deimos.

  14. Effect of surface fields on the dynamic resistance of planar HgCdTe mid-wavelength infrared photodiodes

    NASA Astrophysics Data System (ADS)

    He, Kai; Zhou, Song-Min; Li, Yang; Wang, Xi; Zhang, Peng; Chen, Yi-Yu; Xie, Xiao-Hui; Lin, Chun; Ye, Zhen-Hua; Wang, Jian-Xin; Zhang, Qin-Yao

    2015-05-01

    This work investigates the effect of surface fields on the dynamic resistance of a planar HgCdTe mid-wavelength infrared photodiode from both theoretical and experimental aspects, considering a gated n-on-p diode with the surface potential of its p-region modulated. Theoretical models of the surface leakage current are developed, where the surface tunnelling current in the case of accumulation is expressed by modifying the formulation of bulk tunnelling currents, and the surface channel current for strong inversion is simulated with a transmission line method. Experimental data from the fabricated devices show a flat-band voltage of V F B = - 5.7 V by capacitance-voltage measurement, and then the physical parameters for bulk properties are determined from the resistance-voltage characteristics of the diode working at a flat-band gate voltage. With proper values of the modeling parameters such as surface trap density and channel electron mobility, the theoretical R 0 A product and corresponding dark current calculated from the proposed model as functions of the gate voltage Vg demonstrate good consistency with the measured values. The R 0 A product remarkably degenerates when Vg is far below or above VFB because of the surface tunnelling current or channel current, respectively; and it attains the maximum value of 5.7 × 10 7 Ω . cm 2 around the transition between surface depletion and weak inversion when V g ≈ - 4 V , which might result from reduced generation-recombination current.

  15. Investigations of quantum efficiency in type-II InAs/GaSb very long wavelength infrared superlattice detectors

    NASA Astrophysics Data System (ADS)

    Li, Xiaochao; Jiang, Dongwei; Zhang, Yong; Liu, Gang; Wang, Dongbo; Yu, Qingjiang; Zhao, Liancheng

    2016-04-01

    In this paper, we have investigated the quantum efficiency (QE) of InAs/GaSb T2SL very long wavelength Infrared (VLWIR) photodetectors with 50% cutoff of 12.7 μm. Due to the small depletion width and similar absorption coefficient in the T2SL material system, the minority-carrier diffusion length was determined as the key element to improve the QE of VLWIR T2SL photodetectors. The minority-carrier diffusion length was estimated by a comparison of the experimental data with the Hovel model. Our result suggest that the short hole diffusion length (Lh ∼ 520 nm) and the large its ratio to the width of this region (xn/Lh) are considered against the photo-excited carrier collection in the T2SL photodetectors. In addition, the influence of surface recombination velocity (Sh) on the QE of the T2SL photodetectors is also studied. The change of QE with Sh is not so significant due to the relatively low absorption coefficient and short hole diffusion length in our photodetector.

  16. Minority carrier lifetimes of metalorganic chemical vapor deposition long-wavelength infrared HgCdTe on GaAs

    NASA Astrophysics Data System (ADS)

    Zucca, R.; Edwall, D. D.; Chen, J. S.; Johnston, S. L.; Younger, C. R.

    1991-10-01

    Metalorganic chemical vapor deposition (MOCVD) growth of HgCdTe on GaAs is a promising technique that overcomes the size and crystal quality limitations of CdTe substrates. An important material parameter is the minority carrier liftetime, which determines the ultimate zero bias impedance and quantum efficiency of a photodiode. We present the first systematic study of the temperature and carrier concentration dependence of minority carrier lifetimes on n-type and p-type layers of MOCVD long-wavelength infrared HgCdTe grown on GaAs substrates. The temperature dependencies of the lifetime are compared with theoretical predictions based on Auger, radiative, and Shockley-Read recombination. Excellent fits are obtained over a broad temperature range, from 20 K to room temperature. The experimental lifetimes of n-type material reach the theoretical limit imposed by Auger+radiative recombination for carrier concentrations higher than 2×1015 cm-3. For lower carrier concentrations, the measured lifetimes are shorter than those predicted from Auguer+radiative recombination, and Shockley-Read recombination must be added to the calculations. The lifetimes of arsenic-doped and vacancy-doped p-type material are Shockley-Read limited. They are one order of magnitude longer than those previously observed on vacancy-doped liquid phase epitaxy material.

  17. Resistance-area product of diodes in a long-wavelength infrared HgCdTe mosaic array

    NASA Astrophysics Data System (ADS)

    Gopal, Vishnu; Dhar, Vikram

    2002-02-01

    A long wavelength infrared (LWIR) 2D (mosaic) diode array has been studied by numerically solving the diffusion equation in terms of thermally generated carriers in a n +-on-p HgCdTe diode in an array environment. The results are presented in terms of the resistance-area ( RA) product, in the diffusion-limited case. The results are compared with analytical expressions in the limiting case of the infinite diode. For a finite diode, with a definite junction depth, and a diode size that is smaller than the pitch, the RA, obtained from quasi-3D calculations, is smaller than that expected for the infinite diode case, the deviation being greater for small diodes. Commonly in the literature, the theoretical values of the infinite (1D) diode - which are overestimates - are stated as experimental targets. In the present calculations, the volume of the diode is considered to consist of two parts: one that contributes to the lateral diffusion current that is collected by the four lateral faces of the diode junction, and another that is the `normal' diffusion current, collected by the planar part of the junction from the volume `under' the diode. For the infinite diode case, only the latter component exists. The effect of the perimeter-to-area ratio on the RA in an array environment has been studied. The effective diffusion length associated with the finite diode geometry in an array differs from the standard diffusion length.

  18. Noninvasive and Reversible Cell Adhesion and Detachment via Single-Wavelength Near-Infrared Laser Mediated Photoisomerization.

    PubMed

    Li, Wei; Chen, Zhaowei; Zhou, Li; Li, Zhenhua; Ren, Jinsong; Qu, Xiaogang

    2015-07-01

    Dynamically regulating cell-molecule interactions is fundamental to a variety of biological and biomedical applications. Herein, for the first time, by utilizing spiropyran conjugated multishell upconversion nanoparticles (UCNPs) as a new generation of single-wavelength near-infrared (NIR)-controlled photoswitch, we report a simple yet versatile strategy for controlling cell adhesion/detachment reversibly and noninvasively. Specifically, the two-way isomerization of the photoswitch was merely dependent on the excitation power density of the 980 nm laser. At high power density, the ring-opening was prominent, whereas its reverse ring-closing process occurred upon irradiation by the same laser but with the lower power density. Such transformations made the interactions between spiropyran and cell surface protein fibronectin switchable, thus leading to reversible cell adhesion and detachment. Moreover, efficient adhesion-and-detachment of cells could be realized even after 10 cycles. Most importantly, the utilization of NIR not only showed little damage toward cells, but also improved penetration depth. Our work showed promising potential for in vivo dynamically manipulating cell-molecule interactions and biological process. PMID:26020685

  19. Effect of red and near-infrared wavelengths on low-level laser (light) therapy-induced healing of partial-thickness dermal abrasion in mice.

    PubMed

    Gupta, Asheesh; Dai, Tianhong; Hamblin, Michael R

    2014-01-01

    Low-level laser (light) therapy (LLLT) promotes wound healing, reduces pain and inflammation, and prevents tissue death. Studies have explored the effects of various radiant exposures on the effect of LLLT; however, studies of wavelength dependency in in vivo models are less common. In the present study, the healing effects of LLLT mediated by different wavelengths of light in the red and near-infrared (NIR) wavelength regions (635, 730, 810, and 980 nm) delivered at constant fluence (4 J/cm(2)) and fluence rate (10 mW/cm(2)) were evaluated in a mouse model of partial-thickness dermal abrasion. Wavelengths of 635 and 810 nm were found to be effective in promoting the healing of dermal abrasions. However, treatment using 730- and 980-nm wavelengths showed no sign of stimulated healing. Healing was maximally augmented in mice treated with an 810-nm wavelength, as evidenced by significant wound area reduction (p < 0.05), enhanced collagen accumulation, and complete re-epithelialization as compared to other wavelengths and non-illuminated controls. Significant acceleration of re-epithelialization and cellular proliferation revealed by immunofluorescence staining for cytokeratin-14 and proliferating cell nuclear antigen (p < 0.05) was evident in the 810-nm wavelength compared with other groups. Photobiomodulation mediated by red (635 nm) and NIR (810 nm) light suggests that the biological response of the wound tissue depends on the wavelength employed. The effectiveness of 810-nm wavelength agrees with previous publications and, together with the partial effectiveness of 635 nm and the ineffectiveness of 730 and 980 nm wavelengths, can be explained by the absorption spectrum of cytochrome c oxidase, the candidate mitochondrial chromophore in LLLT. PMID:23619627

  20. Infrared Multiple Photon Dissociation Spectroscopy of a Gas-Phase Oxo-Molybdenum Complex with 1,2-Dithiolene Ligands

    PubMed Central

    2015-01-01

    Electrospray ionization (ESI) in the negative ion mode was used to create anionic, gas-phase oxo-molybdenum complexes with dithiolene ligands. By varying ESI and ion transfer conditions, both doubly and singly charged forms of the complex, with identical formulas, could be observed. Collision-induced dissociation (CID) of the dianion generated exclusively the monoanion, while fragmentation of the monoanion involved decomposition of the dithiolene ligands. The intrinsic structure of the monoanion and the dianion were determined by using wavelength-selective infrared multiple-photon dissociation (IRMPD) spectroscopy and density functional theory calculations. The IRMPD spectrum for the dianion exhibits absorptions that can be assigned to (ligand) C=C, C–S, C—C≡N, and Mo=O stretches. Comparison of the IRMPD spectrum to spectra predicted for various possible conformations allows assignment of a pseudo square pyramidal structure with C2v symmetry, equatorial coordination of MoO2+ by the S atoms of the dithiolene ligands, and a singlet spin state. A single absorption was observed for the oxidized complex. When the same scaling factor employed for the dianion is used for the oxidized version, theoretical spectra suggest that the absorption is the Mo=O stretch for a distorted square pyramidal structure and doublet spin state. A predicted change in conformation upon oxidation of the dianion is consistent with a proposed bonding scheme for the bent-metallocene dithiolene compounds [Lauher, J. W.; Hoffmann, R. J. Am. Chem. Soc.1976, 98, 1729−1742], where a large folding of the dithiolene moiety along the S···S vector is dependent on the occupancy of the in-plane metal d-orbital. PMID:24988369

  1. Room-temperature continuous-wave operation of lateral current injection wavelength-scale embedded active-region photonic-crystal laser.

    PubMed

    Matsuo, Shinji; Takeda, Koji; Sato, Tomonari; Notomi, Masaya; Shinya, Akihiko; Nozaki, Kengo; Taniyama, Hideaki; Hasebe, Koichi; Kakitsuka, Takaaki

    2012-02-13

    We have developed a wavelength-scale embedded active-region photonic-crystal laser using lateral p-i-n structure. Zn diffusion and Si ion implantation are used for p- and n-type doping. Room-temperature continuous-wave lasing behavior is clearly observed from the injection current dependence of the output power, 3dB-bandwidth of the peak, and lasing wavelength. The threshold current is 390 μA and the estimated effective threshold current is 9.4 μA. The output power in output waveguide is 1.82 μW for a 2.0-mA current injection. These results indicate that the embedded active-region structure effectively reduce the thermal resistance. Ultrasmall electrically driven lasers are an important step towards on-chip photonic network applications. PMID:22418134

  2. About the Heisenberg's uncertainty principle and the determination of effective optical indices in integrated photonics at high sub-wavelength regime

    NASA Astrophysics Data System (ADS)

    Bêche, B.; Gaviot, E.

    2016-04-01

    Within the Heisenberg's uncertainty principle it is explicitly discussed the impact of these inequalities on the theory of integrated photonics at sub-wavelength regime. More especially, the uncertainty of the effective index values in nanophotonics at sub-wavelength regime, which is defined as the eigenvalue of the overall opto-geometric problems in integrated photonics, appears directly stemming from Heisenberg's uncertainty. An apt formula is obtained allowing us to assume that the incertitude and the notion of eigenvalue called effective optical index or propagation constant is inversely proportional to the spatial dimensions of a given nanostructure yielding a transfer of the fuzziness on relevant senses of eigenvalues below a specific limit's volume.

  3. Massive photons: An infrared regularization scheme for lattice QCD+QED

    DOE PAGESBeta

    Endres, Michael G.; Shindler, Andrea; Tiburzi, Brian C.; Walker-Loud, Andre

    2016-08-10

    The commonly adopted approach for including electromagnetic interactions in lattice QCD simulations relies on using finite volume as the infrared regularization for QED. The long-range nature of the electromagnetic interaction, however, implies that physical quantities are susceptible to power-law finite volume corrections, which must be removed by performing costly simulations at multiple lattice volumes, followed by an extrapolation to the infinite volume limit. In this work, we introduce a photon mass as an alternative means for gaining control over infrared effects associated with electromagnetic interactions. We present findings for hadron mass shifts due to electromagnetic interactions (i.e., for the proton,more » neutron, charged and neutral kaon) and corresponding mass splittings, and compare the results with those obtained from conventional QCD+QED calculations. Results are reported for numerical studies of three flavor electroquenched QCD using ensembles corresponding to 800 MeV pions, ensuring that the only appreciable volume corrections arise from QED effects. The calculations are performed with three lattice volumes with spatial extents ranging from 3.4 - 6.7 fm. As a result, we find that for equal computing time (not including the generation of the lattice configurations), the electromagnetic mass shifts can be extracted from computations on a single (our smallest) lattice volume with comparable or better precision than the conventional approach.« less

  4. Infrared Multiple-Photon Dissociation spectroscopy of group II metal complexes with salicylate

    SciTech Connect

    Ryan P. Dain; Gary Gresham; Gary S. Groenewold; Jeffrey D. Steill; Jos Oomens; Michael J. van Stipdonk

    2011-07-01

    Ion-trap tandem mass spectrometry with collision-induced dissociation, and the combination of infrared multiple-photon dissociation (IRMPD) spectroscopy and density functional theory (DFT) calculations were used to characterize singly-charged, 1:1 complexes of Ca2+, Sr2+ and Ba2+ with salicylate. For each metal-salicylate complex, the CID pathways are: (a) elimination of CO2 and (b) formation of [MOH]+ where M=Ca2+, Sr2+ or Ba2+. DFT calculations predict three minima for the cation-salicylate complexes which differ in the mode of metal binding. In the first, the metal ion is coordinated by O atoms of the (neutral) phenol and carboxylate groups of salicylate. In the second, the cation is coordinated by phenoxide and (neutral) carboxylic acid groups. The third mode involves coordination by the carboxylate group alone. The infrared spectrum for the metal-salicylate complexes contains a number of absorptions between 1000 – 1650 cm-1, and the best correlation between theoretical and experimental spectra for the structure that features coordination of the metal ion by phenoxide and the carbonyl group of the carboxylic acid group, consistent with calculated energies for the respective species.

  5. FAST TRACK COMMUNICATION: Emission wavelength extension of mid-infrared InAsSb/InP nanostructures using InGaAsSb sandwich layers

    NASA Astrophysics Data System (ADS)

    Lei, W.; Tan, H. H.; Jagadish, C.

    2010-08-01

    This paper presents a study on the emission wavelength extension of InAsSb nanostructures using InGaAsSb sandwich layers. Due to the reduced lattice mismatch between InAsSb nanostructure layer and buffer/capping layer, the introduction of InGaAsSb sandwich layers leads to larger island size, reduced compressive strain and lower confinement barrier for InAsSb nanostructures, thus resulting in a longer emission wavelength. For InGaAsSb sandwich layers with nominal Sb concentration higher than 10%, type II band alignment is observed for the InAsSb/InGaAsSb heterostructure, which also contributes to the extension of emission wavelength. The InGaAsSb sandwich layers provide an effective approach to extend the emission wavelength of InAsSb nanostructures well beyond 2 µm, which is very useful for device applications in the mid-infrared region.

  6. Infrared

    NASA Astrophysics Data System (ADS)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  7. Design and realization of one-dimensional double hetero-structure photonic crystals for infrared-radar stealth-compatible materials applications

    SciTech Connect

    Wang, Zhixun; Cheng, Yongzhi Nie, Yan; Wang, Xian; Gong, Rongzhou

    2014-08-07

    In this paper, a new type one-dimensional (1D) double hetero-structure composite photonic crystal (CPC) for infrared-radar stealth-compatible materials applications was proposed and studied numerically and experimentally. First, based on transfer matrix method of thin-film optical theory, the propagation characteristics of the proposed structure comprising a stack of different alternating micrometer-thick layers of germanium and zinc sulfide were investigated numerically. Calculation results exhibit that this 1D single hetero-structure PC could achieve a flat high reflectivity gradually with increasing the number of the alternating media layers in a single broadband range. Then, based on principles of distributed Bragg reflector micro-cavity, a 1D double hetero-structure CPC comprising four PCs with thickness of 0.797 μm, 0.592 μm, 1.480 μm, and 2.114 μm, respectively, was proposed. Calculation results exhibit that this CPC could achieve a high reflectance of greater than 0.99 in the wavelength ranges of 3–5 μm and 8–14 μm and agreed well with experiment. Further experiments exhibit that the infrared emissivity of the proposed CPC is as low as 0.073 and 0.042 in the wavelength ranges of 3–5 μm and 8–12 μm, respectively. In addition, the proposed CPC can be used to construct infrared-radar stealth-compatible materials due to its high transmittance in radar wave band.

  8. Mid-infrared passively switched pulsed dual wavelength Ho3+-doped fluoride fiber laser at 3 μm and 2 μm

    PubMed Central

    Li, Jianfeng; Luo, Hongyu; Wang, Lele; Liu, Yong; Yan, Zhijun; Zhou, Kaiming; Zhang, Lin; Turistsyn, Sergei K.

    2015-01-01

    Cascade transitions of rare earth ions involved in infrared host fiber provide the potential to generate dual or multiple wavelength lasing at mid-infrared region. In addition, the fast development of saturable absorber (SA) towards the long wavelengths motivates the realization of passively switched mid-infrared pulsed lasers. In this work, by combing the above two techniques, a new phenomenon of passively Q-switched ~3 μm and gain-switched ~2 μm pulses in a shared cavity was demonstrated with a Ho3+-doped fluoride fiber and a specifically designed semiconductor saturable absorber (SESAM) as the SA. The repetition rate of ~2 μm pulses can be tuned between half and same as that of ~3 μm pulses by changing the pump power. The proposed method here will add new capabilities and more flexibility for generating mid-infrared multiple wavelength pulses simultaneously that has important potential applications for laser surgery, material processing, laser radar, and free-space communications, and other areas. PMID:26041105

  9. Photoelectron angular distributions in infrared one-photon and two-photon ionization of FEL-pumped Rydberg states of helium

    NASA Astrophysics Data System (ADS)

    Mondal, S.; Fukuzawa, H.; Motomura, K.; Tachibana, T.; Nagaya, K.; Sakai, T.; Matsunami, K.; Yase, S.; Yao, M.; Wada, S.; Hayashita, H.; Saito, N.; Callegari, C.; Prince, K. C.; O'Keeffe, P.; Bolognesi, P.; Avaldi, L.; Miron, C.; Nagasono, M.; Togashi, T.; Yabashi, M.; Ishikawa, K. L.; Sazhina, I. P.; Kazansky, A. K.; Kabachnik, N. M.; Ueda, K.

    2013-10-01

    The photoelectron angular distributions (PADs) have been investigated for infrared (IR) ionization of He atoms excited to Rydberg states by extreme ultraviolet free-electron laser pulses. The experiment was carried out with two pulses which do not overlap in time. Depending on the intensity of the IR pulses, one IR photon ionization or additionally two-photon above-threshold ionization is observed. For low IR intensity, the PAD is well described by a contribution of s and d partial waves in accordance with early experiments. At high IR intensity, the PAD for two IR photon ionization clearly shows the contribution of higher partial waves. The experimental data are compared with the results of theoretical calculations based on solving the time-dependent Schrödinger equation.

  10. Analysis of one-dimensional photonic band gap structures with a liquid crystal defect towards development of fiber-optic tunable wavelength filters.

    PubMed

    Del Villar, Ignacio; Matias, Ignacio; Arregui, Francisco; Claus, Richard

    2003-03-10

    A theoretical analysis of a fiber optical photonic band gap based tunable wavelength filter is presented. The design presented here is based on the quarter wave reflector with a liquid crystal defect layer in the middle of the structure. The filter generated by the structure is shifted in wavelength as the voltage applied to the structure is modified. Some critical parameters are analyzed: the effect of the consideration of fiber as the first layer and not the input medium in the shape of the filter, the number of layers of the structure, and the thickness of the defect layer. This last parameter determines the width of the wavelength sweep of the filter, but is limited by the creation of more defects. Some rules of practical implementation of this device are also given. PMID:19461749

  11. Tellurite glass defect-core spiral photonic crystal fiber with low loss and large negative flattened dispersion over S + C + L + U wavelength bands.

    PubMed

    Hasan, Md Rabiul; Hasan, Md Imran; Anower, Md Shamim

    2015-11-10

    A defected-core spiral photonic crystal fiber is proposed to achieve very large negative flattened dispersion and small confinement loss. Simulation results reveal that the designed structure exhibits very large flattened dispersion over S+C+L+U wavelength bands and an average dispersion of about -720.7  ps nm(-1) km(-1) with an absolute dispersion variation of 12.7  ps nm(-1)  km(-1) over the wavelength ranging from 1.45 to 1.65 μm. The proposed fiber has five air-hole rings in the cladding leading to very small confinement loss of 0.00111  dB/km at the excitation wavelength of 1.55 μm. The tolerance of the fiber dispersion of ±2% changing in the structural parameters is investigated for practical conditions. PMID:26560773

  12. pnCCD for photon detection from near-infrared to X-rays

    NASA Astrophysics Data System (ADS)

    Meidinger, Norbert; Andritschke, Robert; Hartmann, Robert; Herrmann, Sven; Holl, Peter; Lutz, Gerhard; Strüder, Lothar

    2006-09-01

    A pnCCD is a special type of charge-coupled device developed for spectroscopy and imaging of X-rays with high time resolution and quantum efficiency. Its most famous application is the operation on the XMM-Newton satellite, an X-ray astronomy mission that was launched by the European space agency in 1999. The excellent performance of the focal plane camera has been maintained for more than 6 years in orbit. The energy resolution in particular has shown hardly any degradation since launch. In order to satisfy the requirements of future X-ray astronomy missions as well as those of ground-based experiments, a new type of pnCCD has been developed. This ‘frame-store pnCCD’ shows an enhanced performance compared to the XMM-Newton type of pnCCD. Now, more options in device design and operation are available to tailor the detector to its respective application. Part of this concept is a programmable analog signal processor, which has been developed for the readout of the CCD signals. The electronic noise of the new detector has a value of only 2 electrons equivalent noise charge (ENC), which is less than half of the figure achieved for the XMM-Newton-type pnCCD. The energy resolution for the Mn-Kα line at 5.9 keV is approximately 130 eV FWHM. We have close to 100% quantum efficiency for both low- and high-energy photon detection (e.g. the C-K line at 277 eV, and the Ge-Kα line at 10 keV, respectively). Very high frame rates of 1000 images/s have been achieved due to the ultra-fast readout accomplished by the parallel architecture of the pnCCD and the analog signal processor. Excellent spectroscopic performance is shown even at the relatively high operating temperature of -25 °C that can be achieved by a Peltier cooler. The applications of the low-noise and fast pnCCD detector are not limited to the detection of X-rays. With an anti-reflective coating deposited on the photon entrance window, we achieve high quantum efficiency also for near-infrared and optical

  13. Optical, spectral and phase-matching properties of BIBO, BBO and LBO crystals for optical parametric oscillation in the visible and near-infrared wavelength ranges

    NASA Astrophysics Data System (ADS)

    Akbari, R.; Major, A.

    2013-03-01

    The phase-matching properties of BIBO, BBO and LBO crystals for optical parametric oscillators (OPO) with wavelength tuning in the visible and near infrared spectral ranges were numerically investigated. The phase-matching configurations with a pump wavelength of 520 nm that provide the largest effective nonlinearity in each crystal were considered and compared. In addition, dispersive characteristics, including the group velocity mismatch and group velocity dispersion, which are of significant importance in femtosecond OPOs, were calculated. Finally, the attainable gain bandwidths for each crystal were estimated.

  14. Extended long-wavelength lambda = 11-15-micron GaAs/Al(x)Ga(1-x)As quantum-well infrared photodetectors

    NASA Technical Reports Server (NTRS)

    Zussman, A.; Levine, B. F.; Kuo, J. M.; De Jong, J.

    1991-01-01

    Success has been achieved in extending the spectral wavelength of GaAs/Al(x)Ga(1-x)As quantum-well infrared photodetectors to significantly longer wavelengths of 11-15 micron. High responsivity of 0.5 A/W, high quantum efficiency of 12 percent, and high detectivity as well as an excellent noise equivalent temperature difference of 4 mK have been achieved at T = 50 K. High performance of 19 mK has also been achieved at an even higher temperature of 60 K.

  15. Flecks in Recessive Stargardt Disease: Short-Wavelength Autofluorescence, Near-Infrared Autofluorescence, and Optical Coherence Tomography

    PubMed Central

    Sparrow, Janet R.; Marsiglia, Marcela; Allikmets, Rando; Tsang, Stephen; Lee, Winston; Duncker, Tobias; Zernant, Jana

    2015-01-01

    Purpose We evaluated the incongruous observation whereby flecks in recessive Stargardt disease (STGD1) can exhibit increased short-wavelength autofluorescence (SW-AF) that originates from retinal pigment epithelium (RPE) lipofuscin, while near-infrared AF (NIR-AF), emitted primarily from RPE melanin, is usually reduced or absent at fleck positions. Methods Flecks in SW- and NIR-AF images and spectral-domain optical coherence tomography (SD-OCT) scans were studied in 19 STGD1 patients carrying disease-causing ABCA4 mutations. Fleck spatial distribution and progression were recorded in serial AF images. Results Flecks observed in SW-AF images typically colocalized with darkened foci in NIR-AF images; the NIR-AF profiles were larger. The decreased NIR-AF signal from flecks preceded apparent changes in SW-AF. Spatiotemporal changes in fleck distribution usually progressed centrifugally, but in one case centripetal expansion was observed. Flecks in SW-AF images corresponded to hyperreflective deposits that progressively traversed photoreceptor-attributable bands in SD-OCT images. Outer nuclear layer (ONL) thickness negatively correlated with expansion of flecks from outer to inner retina. Conclusions In the healthy retina, RPE lipofuscin fluorophores form in photoreceptor cells but are transferred to RPE; thus the SW-AF signal from photoreceptor cells is negligible. In STGD1, NIR-AF imaging reveals that flecks are predominantly hypofluorescent and larger and that NIR-AF darkening occurs prior to heightened SW-AF signal. These observations indicate that RPE cells associated with flecks in STGD1 are considerably changed or lost. Spectral-domain OCT findings are indicative of ongoing photoreceptor cell degeneration. The bright SW-AF signal of flecks likely originates from augmented lipofuscin formation in degenerating photoreceptor cells impaired by the failure of RPE. PMID:26230768

  16. Modelling of illuminated current–voltage characteristics to evaluate leakage currents in long wavelength infrared mercury cadmium telluride photovoltaic detectors

    SciTech Connect

    Gopal, Vishnu E-mail: wdhu@mail.sitp.ac.cn; Qiu, WeiCheng; Hu, Weida E-mail: wdhu@mail.sitp.ac.cn

    2014-11-14

    The current–voltage characteristics of long wavelength mercury cadmium telluride infrared detectors have been studied using a recently suggested method for modelling of illuminated photovoltaic detectors. Diodes fabricated on in-house grown arsenic and vacancy doped epitaxial layers were evaluated for their leakage currents. The thermal diffusion, generation–recombination (g-r), and ohmic currents were found as principal components of diode current besides a component of photocurrent due to illumination. In addition, both types of diodes exhibited an excess current component whose growth with the applied bias voltage did not match the expected growth of trap-assisted-tunnelling current. Instead, it was found to be the best described by an exponential function of the type, I{sub excess} = I{sub r0} + K{sub 1} exp (K{sub 2} V), where I{sub r0}, K{sub 1}, and K{sub 2} are fitting parameters and V is the applied bias voltage. A study of the temperature dependence of the diode current components and the excess current provided the useful clues about the source of origin of excess current. It was found that the excess current in diodes fabricated on arsenic doped epitaxial layers has its origin in the source of ohmic shunt currents. Whereas, the source of excess current in diodes fabricated on vacancy doped epitaxial layers appeared to be the avalanche multiplication of photocurrent. The difference in the behaviour of two types of diodes has been attributed to the difference in the quality of epitaxial layers.

  17. Analysis of temperature dependence of dark current mechanisms for long-wavelength HgCdTe photovoltaic infrared detectors

    NASA Astrophysics Data System (ADS)

    Hu, W. D.; Chen, X. S.; Yin, F.; Quan, Z. J.; Ye, Z. H.; Hu, X. N.; Li, Z. F.; Lu, W.

    2009-05-01

    Resistance-voltage curves of n-on-p Hg1-хCdxTe long-wavelength infrared photodiodes forming 128-element array are measured in the temperature range of 40-150 K. Experimentally obtained characteristics are fitted by the simultaneous-mode nonlinear fitting program. The dark current mechanisms induced by diffusion, generation recombination, trap-assisted tunneling, band-to-band tunneling, and series resistance effect are included in the physical model for R-V curve fitting. Six characteristic parameters as function of temperature are extracted from measured R-V curves. The characteristics of extracted current components at low temperatures indicate significant contributions from tunneling effects, which is the dominant leakage current mechanism for reverse bias greater than approximately 50 mV. The Hg-vacancy-induced acceptor trap tends to invert to donor type at higher temperature, typically larger than 120 K, while it can maintain stable at the temperature of 60-40 K. The stable temperature of ion-implantation-induced traps is about 90-60 K, which possibly tends to be ionized at high temperature. However, a low operation temperature can induce the frozen effects of the ion-implantation-induced donor traps. Fitting certainty analysis shows that the error of one parameter can be magnified when one of the other types of dark current mechanisms dominates the dark current and is even infinitely enlarged under large reverse bias. The different bias regions at which each fitting parameter has the largest influence to the R-V curve should be ascertained. The results of the present work demonstrate that modeling of the dynamic resistance in small voltage range or at just operation temperature are insufficient for determining the mechanism of carrier transport across the Hg1-хCdxTe junction and a detailed theoretical study of the current-voltage characteristics in wider voltage range or at various temperatures should be carried out.

  18. Effect of surface fields on the dynamic resistance of planar HgCdTe mid-wavelength infrared photodiodes

    SciTech Connect

    He, Kai; Wang, Xi; Zhang, Peng; Chen, Yi-Yu; Zhou, Song-Min; Xie, Xiao-Hui; Lin, Chun Ye, Zhen-Hua; Wang, Jian-Xin; Zhang, Qin-Yao; Li, Yang

    2015-05-28

    This work investigates the effect of surface fields on the dynamic resistance of a planar HgCdTe mid-wavelength infrared photodiode from both theoretical and experimental aspects, considering a gated n-on-p diode with the surface potential of its p-region modulated. Theoretical models of the surface leakage current are developed, where the surface tunnelling current in the case of accumulation is expressed by modifying the formulation of bulk tunnelling currents, and the surface channel current for strong inversion is simulated with a transmission line method. Experimental data from the fabricated devices show a flat-band voltage of V{sub FB}=−5.7 V by capacitance-voltage measurement, and then the physical parameters for bulk properties are determined from the resistance-voltage characteristics of the diode working at a flat-band gate voltage. With proper values of the modeling parameters such as surface trap density and channel electron mobility, the theoretical R{sub 0}A product and corresponding dark current calculated from the proposed model as functions of the gate voltage V{sub g} demonstrate good consistency with the measured values. The R{sub 0}A product remarkably degenerates when V{sub g} is far below or above V{sub FB} because of the surface tunnelling current or channel current, respectively; and it attains the maximum value of 5.7×10{sup 7} Ω · cm{sup 2} around the transition between surface depletion and weak inversion when V{sub g}≈−4 V, which might result from reduced generation-recombination current.

  19. Estimated Optical Constants of Calcite at visible to mid-infrared wavelengths (0.3-6 μm)

    NASA Astrophysics Data System (ADS)

    Roush, T. L.

    2010-12-01

    Carbonate minerals are germane to questions involving volatile and climate history on Mars [e.g., 1,2]. Spectral observations provide evidence for the presence of carbonates in the Martian environment [1, 3-7]. Carbonate minerals are identified in Asian [8] and Saharan dust [9-11]. The imaginary index of refraction in the visible to mid-infrared wavelengths (vmir) of has been determined from a few of the many studies of carbonates spanning over 100 years [12-16]. The growing evidence for carbonates on Mars, the presence of carbonates in terrestrial aerosols, and the disagreement among the optical constants for these materials in the vmir has motivated a broader effort to determine the optical constants of carbonates [17-18]. The results of the application of the techniques described in [19] to estimate the optical constants of calcite will be presented. [1] Pollack et al. 1987 Icarus, 71, 203 [2] Fanale et at. 1992 in Mars, U. Arizona Press, 1135 [3] Lellouch et al. 2000 [4] Calvin et al. 1994 JGR. 99, 14659 [5] Bandfield et al. 2003, Science 301, 1084 [6] Ehlmann et al. 2008 Science, 322, 1828 [7] Palomba et al. 2009 Icarus 203, 58 [8] Jeong 2008 JGR., 113, D02208 [9] Glaccum and Prospero 1980 Mar. Geol., 37, 295 [10] Avila et al. 1997 JGR 102, 21,977 [11] Reid et al. 2003 JGR, 108, D19 [12] Nysander, 1909 Phys. Rev. 28, 291 [13] Merrit 1895 Phys. Rev. 2, 424 [14] Hellewege et al. 1970 Z. Phys., 232, 61 [15] Marra, et al. 2006 J. Quant. Spect. & Rad. Trans. 100, 250 [16] Ivalev and Papova 1972 Sov. Phys. J. 5, 91 [17] Roush, 2009 Lunar Planet. Sci. Conf 40, abstract 1080 [18] Roush 2010 Euro. Planet. Sci. Cong. abstract 341 [19] Roush et al. 2007 JGR, 112, E10003

  20. High-visibility two-photon interference at a telecom wavelength using picosecond-regime separated sources

    SciTech Connect

    Aboussouan, Pierre; Alibart, Olivier; Ostrowsky, Daniel B.; Baldi, Pascal; Tanzilli, Sebastien

    2010-02-15

    We report on a two-photon interference experiment in a quantum relay configuration using two picosecond regime periodically poled lithium niobate (PPLN) waveguide based sources emitting paired photons at 1550 nm. The results show that the picosecond regime associated with a guided-wave scheme should have important repercussions for quantum relay implementations in real conditions, essential for improving both the working distance and the efficiency of quantum cryptography and networking systems. In contrast to already reported regimes, namely, femtosecond and CW, it allows achieving a 99% net visibility two-photon interference while maintaining a high effective photon pair rate using only standard telecom components and detectors.