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Sample records for echelle grating spectrometer

  1. Cooled echelle grating spectrometer. [for space telescope applications

    NASA Technical Reports Server (NTRS)

    Beer, R. (Inventor)

    1980-01-01

    A cooled echelle grating spectrometer for detecting wavelengths between one micron and fifteen microns is disclosed. More specifically, the spectrometer has a cross-dispersing grating for ordering infrared energy and an echelle grating for further ordering of the infrared energy. Ordered radiation from the echelle grating is sensed by a detecting means. Also disclosed is use of a Schmidt camera for focusing the further ordered radiation from the echelle grating onto a detector array having individual detectors dispersed on a plane which substantially corresponds to a curved focal plane of the Schmidt camera. A spectrometer constructed according to the teachings of the present invention will continuously cover the spectrum between one micron and fifteen microns and have a resolution of 0.1/cm.

  2. Echelle grating multi-order imaging spectrometer utilizing a catadioptric lens

    DOEpatents

    Chrisp, Michael P; Bowers, Joel M

    2014-05-27

    A cryogenically cooled imaging spectrometer that includes a spectrometer housing having a first side and a second side opposite the first side. An entrance slit is on the first side of the spectrometer housing and directs light to a cross-disperser grating. An echelle immersions grating and a catadioptric lens are positioned in the housing to receive the light. A cryogenically cooled detector is located in the housing on the second side of the spectrometer housing. Light from the entrance slit is directed to the cross-disperser grating. The light is directed from the cross-disperser grating to the echelle immersions grating. The light is directed from the echelle immersions grating to the cryogenically cooled detector on the second side of the spectrometer housing.

  3. An Echelle Grating Spectrometer (EGS) for mid-IR remote chemical detection

    SciTech Connect

    Stevens, C.G.; Thomas, N.; Kuzmenko, P.; Alger, T.

    1994-07-01

    The availability of high performance two-dimensional InSb detectors enables the design and construction of mid-infrared spectrographs capable of obtaining high resolution spectra over extended spectral regions without moving components. Rugged, stable, cryo-cooled spectrographs suitable for remote field operation are now possible using prism-echelle cross dispersion designs. The authors discuss the design, fabrication, and performance of a high resolution mid-IR field spectrograph designed specifically for the detection of atmospheric-borne chemicals from airborne platforms. The instrument design provides maximum optical throughput covering the two atmospheric windows at 2.0-2.5 pm and 3.0-4.2 pm.

  4. Astronomical near-infrared echelle gratings

    NASA Astrophysics Data System (ADS)

    Hinkle, Kenneth H.; Joyce, Richard R.; Liang, Ming

    2014-07-01

    High-resolution near-infrared echelle spectrographs require coarse rulings in order to match the free spectral range to the detector size. Standard near-IR detector arrays typically are 2 K x 2 K or 4 K x 4 K. Detectors of this size combined with resolutions in the range 30000 to 100000 require grating groove spacings in the range 5 to 20 lines/mm. Moderately high blaze angles are desirable to reduce instrument size. Echelle gratings with these characteristics have potential wide application in both ambient temperature and cryogenic astronomical echelle spectrographs. We discuss optical designs for spectrographs employing immersed and reflective echelle gratings. The optical designs set constraints on grating characteristics. We report on market choices for obtaining these gratings and review our experiments with custom diamond turned rulings.

  5. Spherical grating spectrometers

    NASA Astrophysics Data System (ADS)

    O'Donoghue, Darragh; Clemens, J. Christopher

    2014-07-01

    We describe designs for spectrometers employing convex dispersers. The Offner spectrometer was the first such instrument; it has almost exclusively been employed on satellite platforms, and has had little impact on ground-based instruments. We have learned how to fabricate curved Volume Phase Holographic (VPH) gratings and, in contrast to the planar gratings of traditional spectrometers, describe how such devices can be used in optical/infrared spectrometers designed specifically for curved diffraction gratings. Volume Phase Holographic gratings are highly efficient compared to conventional surface relief gratings; they have become the disperser of choice in optical / NIR spectrometers. The advantage of spectrometers with curved VPH dispersers is the very small number of optical elements used (the simplest comprising a grating and a spherical mirror), as well as illumination of mirrors off axis, resulting in greater efficiency and reduction in size. We describe a "Half Offner" spectrometer, an even simpler version of the Offner spectrometer. We present an entirely novel design, the Spherical Transmission Grating Spectrometer (STGS), and discuss exemplary applications, including a design for a double-beam spectrometer without any requirement for a dichroic. This paradigm change in spectrometer design offers an alternative to all-refractive astronomical spectrometer designs, using expensive, fragile lens elements fabricated from CaF2 or even more exotic materials. The unobscured mirror layout avoids a major drawback of the previous generation of catadioptric spectrometer designs. We describe laboratory measurements of the efficiency and image quality of a curved VPH grating in a STGS design, demonstrating, simultaneously, efficiency comparable to planar VPH gratings along with good image quality. The stage is now set for construction of a prototype instrument with impressive performance.

  6. Optical Alignment and Diffraction Analysis for AIRES: An Airborne Infrared Echelle Spectrometer

    NASA Technical Reports Server (NTRS)

    Haas, Michael R.; Fonda, Mark (Technical Monitor)

    2002-01-01

    The optical design is presented for a long-slit grating spectrometer known as AIRES (Airborne InfraRed Echelle Spectrometer). The instrument employs two gratings in series: a small order sorter and a large steeply blazed echelle. The optical path includes four pupil and four field stops, including two narrow slits. A detailed diffraction analysis is performed using GLAD by Applied Optics Research to evaluate critical trade-offs between optical throughput, spectral resolution, and system weight and volume. The effects of slit width, slit length, oversizing the second slit relative to the first, on- vs off-axis throughput, and clipping at the pupil stops and other optical elements are discussed.

  7. Design considerations for AIRES, an airborne infrared echelle spectrometer for SOFIA

    NASA Technical Reports Server (NTRS)

    Haas, Michael R.; Erickson, Edwin F.; Baltz, James A.; Colgan, Sean W. J.; Lynch, Dana H.; Sablan, Marita

    1996-01-01

    The airborne infrared echelle spectrometer (AIRES) was proposed as a facility instrument for the stratospheric observatory for infrared astronomy (SOFIA) project. The preliminary AIRES design uses multiple two dimensional detector arrays and a 1.2 m long, 76 deg blaze angle echelle to combine high spectral resolution with diffraction limited imaging in the cross-dispersion direction. A preliminary optical design and the mechanical architecture are presented together with the analysis and prototyping of lightweight aluminum echelles. Instrument efficiencies are calculated and compared for different gratings, and the associated mechanical design tradeoffs are discussed.

  8. Design considerations for a large Airborne Infrared Echelle Spectrometer (AIRES)

    NASA Technical Reports Server (NTRS)

    Haas, Michael R.; Erickson, Edwin F.; Colgan, Sean W. J.; Baltz, James A.; Lynch, Dana H.

    1995-01-01

    We propose a new facility instrument, the Airborne Infrared Echelle Spectrometer or 'AIRES'. The scientific rationale, a preliminary optical and mechanical design, and the instrument's estimated performance are presented. Some of the major technical challenges are discussed.

  9. The Cryogenic Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Erickson, Edwin F.; Haas, Michael R.; Colgan, Sean W. J.; Simpson, Janet P.; Rubin, Robert H.

    1995-01-01

    The Cryogenic Grating Spectrometer (CGS) first flew on the KAO in 1982 December and has been open to guest investigators since 1984 October. In the past 12 years it has completed over 100 research flights supporting 13 different principal investigators studying a variety of objects. We briefly describe the instrument, its capabilities and accomplishments, and acknowledge the people who have contributed to its development and operation.

  10. AIRES: an Airborne Infra-Red Echelle Spectrometer for SOFIA

    NASA Astrophysics Data System (ADS)

    Erickson, E. F.; Haas, M. R.; Colgan, S. W. J.; Roellig, T.; Simpson, J. P.; Telesco, C. M.; Pina, R. K.; Young, E. T.; Wolf, J.

    1997-12-01

    The Stratospheric Observatory for Infrared Astronomy, SOFIA, is a 2.7 meter telescope which is scheduled to begin observations in a Boeing 747 in October 2001. Among other SOFIA science instruments recently selected for development is the facility spectrometer AIRES. AIRES is designed for studies of a broad range of phenomena occuring in the interstellar medium (ISM) which are uniquely enabled by SOFIA. Examples include accretion and outflow in protostars and young stellar objects, the morphology, dynamics, and excitation of neutral and ionized gas at the Galactic center, and the recycling of material to the ISM from evolved stars. Astronomers using AIRES will be able to select any wavelength from 17 to 210 mu m., with corresponding spectral resolving powers ranging from 60,000 to 4000 in less than a minute. This entire wavelength range is important because it contains spectral features, often widely separated in wavelength, which characterize fundamental ISM processes. AIRES will utilize two-dimensional detector arrays and a large echelle grating to achieve spectral imaging with excellent sensitivity and unparalleled angular resolution at these wavelengths. As a facility science instrument, AIRES will provide guest investigators frequent opportunities for far infrared spectroscopic observations when SOFIA begins operations.

  11. First: Florida Ir Silicon Immersion Grating Spectrometer

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Zhao, B.; Wang, J.; Wan, X.; Powell, S.

    2012-01-01

    The FIRST silicon immersion grating spectrometer is being developed at UF to search for habitable Earth-like planets around M dwarfs and giant planets around young active stars. This compact cryogenic IR instrument is designed to have a spectral resolution of R=72,000 at 1.4-1.8 µm with a silicon immersion grating and R=60K at 0.8-1.35 µm with an R4 echelle. The goal is to reach a long term Doppler precision of 1-3 m/s for bright M dwarfs. The FIRST silicon immersion grating, with 54.74 degree blaze angle and 16 l/mm groove density, has been fully characterized in the lab. The 50x50 mm square grating entrance pupil is coated with a single layer of anti-reflection coating resulting in a 2.1% measured reflection loss. The grating surface was coated with a gold layer to increase grating surface reflectivity. It has produced R=110,000 diffraction limited spectral resolution at 1.523 micron in a lab test spectrograph with 20 mm pupil diameter. The integrated scattered light is less than 0.2\\% and grating has no visible ghosts down to the measuring instrument noise level. The grating efficiency is 69\\% at the peak of the blaze. This silicon immersion grating is ready for scientific observations with FIRST. FIRST is scheduled to be integrated in the lab during the spring of 2012 and see the first light at an astronomical telescope (TBD) the summer of 2012.

  12. The design of an echelle spectrometer for diffuse extreme ultraviolet/far ultraviolet astronomy

    NASA Technical Reports Server (NTRS)

    Martin, Christopher

    1986-01-01

    The novel, relatively high-resolution nebular spectrometer design presented incorporates a mechanical precollimator with an objective echelle grating that proceeds to a cross-dispensing Wadsworth configuration; the minimum feasible number of reflections is employed in order to maximize EUV sensitivity. The configuration, which is noted to be capable of yielding a comparatively large field of view for optimal diffuse emission sensitivity, is compact and employs conventionally fabricated optical components and available microchannel plate detectors. The sensitivities obtainable approach the limit stipulated by Liouville's theorem.

  13. Middle-infrared echelle cross-dispersion spectrometer ACS-MIR for the ExoMars Trace Gas Orbiter

    NASA Astrophysics Data System (ADS)

    Trokhimovskiy, Alexander; Korablev, Oleg; Ivanov, Yuriy S.; Siniyavsky, I. I.; Fedorova, Anna; Stepanov, Alexander V.; Titov, Andrei Y.; Patrakeev, Andrei; Moiseev, Pavel P.; Kozlova, Tatiana O.; Montmessin, Franck

    2015-09-01

    The middle-infrared (MIR) echelle spectrometer is one channel of the Atmospheric Chemistry Suite (ACS) package dedicated for the studies of the Martian atmosphere on board ExoMars Trace Gas Orbiter (TGO) planned for launch in 2016. The MIR channel of ACS is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the range of 2.3-4.2 μm with the resolving power of ~50,000. MIR is dedicated to sensitive measurements of trace gases. The MIR channel consists of entry optics, an echelle spectrometer with a 140x250 mm grating and two-mirror collimator, two secondary steerable gratings, and a cryogenically cooled MCT detector array with proximity optics. The spectrometer operates in high orders of diffraction, allowing to acquire up to 17 orders at one detector frame, and to cover simultaneously ~300-nm spectral interval within the spectral range. The mechanism allows moving the secondary grating with a characteristic time of ~0.1 s. This concept is novel for space application. The instrument is a complete block with power and data interfaces, and the overall mass of 12 kg. The protoflight model of MIR is completed, integrated within the ACS suite, and is undergoing tests at the spacecraft.

  14. Detector Arrays for an Airborne Infrared Echelle Spectrometer

    NASA Technical Reports Server (NTRS)

    Erickson, E. F.; Haas, M. R.; Baltz, J. A.; McKelvey, M. E.; Colgan, S. W. J.; Lynch, D. H.; Wolf, J.; Witteborn, Fred (Technical Monitor)

    1996-01-01

    The design of a long-slit echelle spectrograph covering the 16 - 210 micron range for use on the Stratospheric Observatory for Infrared Astronomy (SOFIA) is under study at NASA-Ames. This wavelength range is selected for its content of important astrophysical spectral lines accessible from an airborne platform, and availability of suitable detectors. Two dimensional arrays will be used to simultaneously provide spectral coverage in the dispersion direction and imaging in the cross-dispersion direction. Major goals are: (1) to reach sensitivities limited primarily by the background from the residual atmosphere and the telescope; (2) to provide imaging not far from the diffraction limit of the 2.5 meter (effective) aperture of the telescope; and (3) to obtain diffraction-limited spectral resolution from the large echelle grating, which means that the resolving power increases with decreasing wavelength. To meet these requirements, three detector types are forseen: a commercially available monolithic Si:Sb IBC array to cover the wavelength range from 16 to 40 microns, a Ge:Sb photoconductor array to cover the range from 40 to 125 microns, and a stressed Ge:Ga photoconductor array covering the range from 125 to 210 microns. The paper discusses details of the studies and plans for the field optics, detectors, and readouts.

  15. Exploiting a Transmission Grating Spectrometer

    SciTech Connect

    Ronald E. Bell

    2004-12-08

    The availability of compact transmission grating spectrometers now allows an attractive and economical alternative to the more familiar Czerny-Turner configuration for many high-temperature plasma applications. Higher throughput is obtained with short focal length refractive optics and stigmatic imaging. Many more spectra can be obtained with a single spectrometer since smaller, more densely packed optical input fibers can be used. Multiple input slits, along with a bandpass filter, can be used to maximize the number of spectra per detector, providing further economy. Curved slits can correct for the strong image curvature of the short focal length optics. Presented here are the governing grating equations for both standard and high-dispersion transmission gratings, defining dispersion, image curvature, and desired slit curvature, that can be used in the design of improved plasma diagnostics.

  16. AIRES: An Airborne Infra-Red Echelle Spectrometer for SOFIA

    NASA Technical Reports Server (NTRS)

    Dotson, Jessie J.; Erickson, Edwin F.; Haas, Michael R.; Colgan, Sean W. J.; Simpson, Janet P.; Telesco, Charles M.; Pina, Robert K.; Wolf, Juergen; Young, Erick T.

    1999-01-01

    SOFIA will enable astronomical observations with unprecedented angular resolution at infrared wavelengths obscured from the ground. To help open this new chapter in the exploration of the infrared universe, we are building AIRES, an Airborne Infra-Red Echelle Spectrometer. AIRES will be operated as a first generation, general purpose facility instrument by USRA, NASA's prime contractor for SOFIA. AIRES is a long slit spectrograph operating from 17 - 210 microns. In high resolution mode the spectral resolving power is approx. 10(exp 6) microns/A or approx. 10(exp 4) at 100 microns. Unfortunately, since the conference, a low resolution mode with resolving power about 100 times lower has been deleted due to budgetary constraints. AIRES includes a slit viewing camera which operates in broad bands at 18 and 25 microns.

  17. Low-crosstalk fabrication-insensitive echelle grating multiplexers and passives for the silicon photonics toolbox

    NASA Astrophysics Data System (ADS)

    Sciancalepore, Corrado; Lycett, Richard J.; Dallery, Jacques A.; Pauliac, Sebastien; Hassan, Karim; Harduin, Julie; Duprez, Hlne; Weidenmueller, Ulf; Gallagher, Dominic F. G.; Menezo, Sylvie; Ben-Bakir, Badhise

    2015-02-01

    In this communication, we report about the design, fabrication, and testing of echelle grating (de-)multiplexers for the 100GBASE-LR4 norm and other passive architectures such as vertical fiber-couplers and slow-wave waveguides in the O-band (1.31-?m) for Silicon-based photonic integrated circuits (Si-PICs). In detail, two-point stigmatic 20th-order echelle gratings (TPSGs) on the 300-nm-thick SOI platform designed for 4x800-GHz-spaced wavelength division multiplexing featuring extremely low crosstalk (< -30 dB), precise channel spacing and optimized average insertion losses (~ 3 dB) are presented. Distributed Bragg reflectors (DBRs) are used to improve the grating facets reflectivity, while multi-mode interferometers (MMIs) are used in optimized perfectly-chirped echelle gratings (PCGs) for pass-band flattening. Moreover, 200-mm CMOS pilot lines processing tools including VISTEC variable-shape e-beam lithography are employed for the fabrication. In addition, wafer-level statistics of the multiplexers clearly shows the echelle grating to be inherently fabrication-insensitive to processing drifts, resulting in a minimized dispersion of the multiplexer performances over the wafer. In particular, the echelle grating spectral response remains stable over the wafer in terms of crosstalk, channel spacing and bandwidth, with the wavelength dispersion of the filter comb being limited to just 0.8 nm, thus highlighting the intrinsic robustness of design, fab pathways as well as the reliability of modeling tools. As well as that, apodized one-dimensional vertical fiber couplers, optimized multi-mode interferometers (MMIs) and extremely low-losses slow-light waveguides are demonstrated and discussed. The adiabatic apodization of such 1-D gratings is capable to provide band-edge group indices ng as high as 30 with propagation losses equivalent to the indexlike propagation regime.

  18. High Quality TMAH Etched Silicon Echelle Gratings ready for Astronomical Spectroscopy

    NASA Astrophysics Data System (ADS)

    McDavitt, D.; Wang, J.; Ge, J.; Miller, S.

    2003-12-01

    We report new testing results for infrared silicon diffraction gratings, showing that a new etching process using tetramethyl ammonium hydroxide (TMAH) can fabricate high quality gratings with both fine and coarse grooves (5-200 μ m groove size). We have modeled the diffraction efficiencies of one 13μ m reflection grating sample with the commercially available Grating SOLVER (GSOLVER 4.20) software, and measured the diffraction efficiencies with 64% at λ =543.5 nm and 45% at λ =632.8 nm in a Littrow mounting, which match the modeling curves well within the 1% error bar. The integrated scattered light level is less than 1%. To fully construct the blaze function, we set up an echelle spectrograph with a low dispersion grating as a cross-disperser. We obtained an echelle spectrum with a continuum source and then calibrated the wavelength with a Neon emission lamp. The resolving power of an etched grating with a 10 mm collimated beam is R = 11000, indicating a diffraction-limited performance. The blaze function also matches the theoretical efficiency curve. From these recent testing results, we conclude that the silicon gratings we fabricated with our anisotropic etching technique can satisfy the quality requirements for high resolution astronomical spectrographs in both the visible and near IR. This work was supported by NASA grants NGA5-12115, NAG5-11427, NSF AST-0138235 and the Penn State Eberly College of Science.

  19. Convex Diffraction Grating Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Chrisp, Michael P. (Inventor)

    1999-01-01

    A 1:1 Offner mirror system for imaging off-axis objects is modified by replacing a concave spherical primary mirror that is concentric with a convex secondary mirror with two concave spherical mirrors M1 and M2 of the same or different radii positioned with their respective distances d1 and d2 from a concentric convex spherical diffraction grating having its grooves parallel to the entrance slit of the spectrometer which replaces the convex secondary mirror. By adjusting their distances d1 and d2 and their respective angles of reflection alpha and beta, defined as the respective angles between their incident and reflected rays, all aberrations are corrected without the need to increase the spectrometer size for a given entrance slit size to reduce astigmatism, thus allowing the imaging spectrometer volume to be less for a given application than would be possible with conventional imaging spectrometers and still give excellent spatial and spectral imaging of the slit image spectra over the focal plane.

  20. Imaging spectrometer/camera having convex grating

    NASA Technical Reports Server (NTRS)

    Reininger, Francis M. (Inventor)

    2000-01-01

    An imaging spectrometer has fore-optics coupled to a spectral resolving system with an entrance slit extending in a first direction at an imaging location of the fore-optics for receiving the image, a convex diffraction grating for separating the image into a plurality of spectra of predetermined wavelength ranges; a spectrometer array for detecting the spectra; and at least one concave sperical mirror concentric with the diffraction grating for relaying the image from the entrance slit to the diffraction grating and from the diffraction grating to the spectrometer array. In one embodiment, the spectrometer is configured in a lateral mode in which the entrance slit and the spectrometer array are displaced laterally on opposite sides of the diffraction grating in a second direction substantially perpendicular to the first direction. In another embodiment, the spectrometer is combined with a polychromatic imaging camera array disposed adjacent said entrance slit for recording said image.

  1. Compact Imaging Spectrometer Utilizing Immersed Gratings

    DOEpatents

    Chrisp, Michael P. (Danville, CA); Lerner, Scott A. (Corvallis, OR); Kuzmenko, Paul J. (Livermore, CA); Bennett, Charles L. (Livermore, CA)

    2006-03-21

    A compact imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The imaging spectrometer comprises an entrance slit for transmitting light, a system for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the system for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the system for receiving the light and the system for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light through an optical element to the detector array.

  2. An FIR cooled grating spectrometer for the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Erickson, E. F.; Haas, M. R.; Hollenbach, D. J.; Simpson, J. P.; Augason, G. C.; Houck, J. R.; Harwit, M. O.; Rank, D. M.

    1985-01-01

    The design and performance of a liquid-He-cooled spectrometer being developed for the Kuiper Airborne Observatory (KAO) to study FIR lines originating in the interstellar medium are discussed. Currently, the spectrometer contains six Ge:Ga photoconductor detectors mounted in integrating cavities and cooled to about 3 K; the collimator focal plane has space for 39 such detectors. The instrument achieves a maximum resolving power of 6000 by means of a 45-cm long echelle grating and is optically capable of operating in the spectral range 25-300 microns. A laboratory spectrum of water vapor, an atmospheric water absorption feature measured from the KAO with Mars as a source, and the forbidden O(2+) emission from W51-IRS1 are shown.

  3. Compact imaging spectrometer utilizing immersed gratings

    DOEpatents

    Lerner, Scott A.

    2005-12-20

    A compact imaging spectrometer comprising an entrance slit for directing light, lens means for receiving the light, refracting the light, and focusing the light; an immersed diffraction grating that receives the light from the lens means and defracts the light, the immersed diffraction grating directing the detracted light back to the lens means; and a detector that receives the light from the lens means.

  4. Compact imaging spectrometer utilizing immersed gratings

    SciTech Connect

    Chrisp, Michael P.; Lerner, Scott A.; Kuzmenko, Paul J.; Bennett, Charles L.

    2007-07-03

    A compact imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The imaging spectrometer comprises an entrance slit for transmitting light, means for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the means for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the means for receiving the light and the means for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light to the means for receiving the light, and the means for receiving the light directs the light to the detector array.

  5. Compact reflective imaging spectrometer utilizing immersed gratings

    DOEpatents

    Chrisp, Michael P. (Danville, CA)

    2006-05-09

    A compact imaging spectrometer comprising an entrance slit for directing light, a first mirror that receives said light and reflects said light, an immersive diffraction grating that diffracts said light, a second mirror that focuses said light, and a detector array that receives said focused light. The compact imaging spectrometer can be utilized for remote sensing imaging spectrometers where size and weight are of primary importance.

  6. Facet-rotated echelle grating for cyclic wavelength router with uniform loss and flat passband.

    PubMed

    Mu, Ge; Huang, Pingli; Wu, Lin; He, Jian-Jun

    2015-09-01

    A novel method for designing a cyclic echelle grating wavelength router with uniform loss and flat passband is proposed and experimentally demonstrated. A 44 cyclic wavelength router with a channel spacing of 400 GHz at 1550 nm wavelength band is designed and fabricated in InP. Measurement results show that the loss of 16 input-output combinations varies from 9 to 19.3 dB in a conventional design, with a nonuniformity of 10.3 dB, while the 1-dB spectral bandwidth is only 0.3 nm. By rotating angles of grating facets according to an appropriately designed distribution function, the loss nonuniformity is reduced to 1.5 dB, and a flat-top spectral response with 1 dB bandwidth of 1.0 nm is achieved simultaneously. PMID:26368691

  7. Micro Ring Grating Spectrometer with Adjustable Aperture

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor); Choi, Sang H. (Inventor)

    2012-01-01

    A spectrometer includes a micro-ring grating device having coaxially-aligned ring gratings for diffracting incident light onto a target focal point, a detection device for detecting light intensity, one or more actuators, and an adjustable aperture device defining a circular aperture. The aperture circumscribes a target focal point, and directs a light to the detection device. The aperture device is selectively adjustable using the actuators to select a portion of a frequency band for transmission to the detection device. A method of detecting intensity of a selected band of incident light includes directing incident light onto coaxially-aligned ring gratings of a micro-ring grating device, and diffracting the selected band onto a target focal point using the ring gratings. The method includes using an actuator to adjust an aperture device and pass a selected portion of the frequency band to a detection device for measuring the intensity of the selected portion.

  8. A Cooled Grating Spectrometer Using Cylindrical Optics

    NASA Astrophysics Data System (ADS)

    Jones, T. J.; Hyland, A. R.; Dopita, M. A.; Hart, J.; Conroy, P.; Hillier, J.

    1982-02-01

    A grating spectrometer for use from 1-5 μm with all optics including two gratings cooled to cryogenic temperatures is described. In order to make the optical system as compact as possible, the novel design uses cylindrical teleconverter optics. This enables a resolving power of R ˜ 3 × 103 to be achieved at 2.3 μm with a 2.7 arc sec entrance aperture on the Mount Stromlo 1.9-meter telescope. Also described is a second-generation spectrometer, employing a cooled solid Fabry-Perot etalon for a higher resolution capability, that is currently under development.

  9. New Convex Grating Types for Concentric Imaging Spectrometers

    NASA Technical Reports Server (NTRS)

    Mouroulis, P.; Wilson, D. W.; Maker, P. D.; Maker, R. E.; Muller, R. E.

    1998-01-01

    The properties of convex gratings fabricated by electron-beam lithography are investigated. Three grating types are shown. These gratings allow the optical designer to fully realize the considerable advantages of concentric spectrometer forms.

  10. Electro-optic Phase Grating Streak Spectrometer

    SciTech Connect

    Goldin, F. J.

    2012-08-02

    The electro-optic phase grating streak spectrometer (EOPGSS) generates a time-resolved spectra equivalent to that obtained with a conventional spectrometer/streak camera combination, but without using a streak camera (by far the more expensive and problematic component of the conventional system). The EOPGSS is based on a phase, rather than an amplitude grating. Further, this grating is fabricated of electro-optic material such as, for example, KD*P, by either etching grooves into an E-O slab, or by depositing lines of the E-O material onto an optical flat. An electric field normal to the grating alters the material’s index of refraction and thus affects a shift (in angle) of the output spectrum. Ramping the voltage streaks the spectrum correspondingly. The streak and dispersion directions are the same, so a second (static, conventional) grating disperses the spectrum in the orthogonal direction to prevent different wavelengths from “overwriting” each other. Because the streaking is done by the grating, the streaked output spectrum is recorded with a time-integrating device, such as a CCD. System model, typical design, and performance expectations will be presented.

  11. The Constellation-X Reflection Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Allen, Jean C.

    2006-01-01

    The Reflection Grating Spectrometer on the Constellation-X mission will provide high sensitivity, high-resolution spectra in the soft x-ray band. The RGS performance requirements are specified as a resolving power of greater than 300 and an effective area of greater than 1000 sq cm across most of the 0.25 to 2.0 keV band. These requirements are driven by the science goals of the mission. We will describe the performance requirements and goals, the reference design of the spectrometer, and examples of science cases where we expect data from the RGS to significantly advance our current understanding of the universe.

  12. Development of infrared Echelle spectrograph and mid-infrared heterodyne spectrometer on a small telescope at Haleakala, Hawaii for planetary observation

    NASA Astrophysics Data System (ADS)

    Sakanoi, Takeshi; Kasaba, Yasumasa; Kagitani, Masato; Nakagawa, Hiromu; Kuhn, Jeff; Okano, Shoichi

    2014-08-01

    We report the development of infrared Echelle spectrograph covering 1 - 4 micron and mid-infrared heterodyne spectrometer around 10 micron installed on the 60-cm telescope at the summit of Haleakala, Hawaii (alt.=3000m). It is essential to carry out continuous measurement of planetary atmosphere, such as the Jovian infrared aurora and the volcanoes on Jovian satellite Io, to understand its time and spatial variations. A compact and easy-to-use high resolution infrared spectrometer provide the good opportunity to investigate these objects continuously. We are developing an Echelle spectrograph called ESPRIT: Echelle Spectrograph for Planetary Research In Tohoku university. The main target of ESPRIT is to measure the Jovian H3+ fundamental line at 3.9 micron, and H2 nu=1 at 2.1 micron. The 256x256 pixel CRC463 InSb array is used. An appropriate Echelle grating is selected to optimize at 3.9 micron and 2.1 micron for the Jovian infrared auroral observations. The pixel scale corresponds to the atmospheric seeing (0.3 arcsec/pixel). This spectrograph is characterized by a long slit field-of-view of ~ 50 arcsec with a spectral resolution is over 20,000. In addition, we recently developed a heterodyne spectrometer called MILAHI on the 60 cm telescope. MILAHI is characterized by super high-resolving power (more than 1,500,000) covering from 7 - 13 microns. Its sensitivity is 2400 K at 9.6 micron with a MCT photo diode detector of which bandwidth of 3000 MHz. ESPRIT and MILAHI is planned to be installed on 60 cm telescope is planned in 2014.

  13. Development of a broadband submillimeter grating spectrometer

    NASA Astrophysics Data System (ADS)

    Benford, Dominic J.; Serabyn, Eugene; Phillips, Thomas G.; Moseley, S. H.

    1998-07-01

    One of the central issues in astronomy is the formation and evolution of galaxies at large redshifts. Submillimeter observations are essential to understanding these processes. One of the best prospects for high redshift submillimeter observations is the study of the C(subscript II) 158 micrometer fine- structure line, which carries about 0.2% of the total luminosity of nearby starburst galaxies. However, current heterodyne receivers at submillimeter observatories have insufficient bandwidth to detect the full extent of highly broadened emission lines. We are developing a broadband grating spectrometer for the Caltech Submillimeter Observatory with a total bandwidth of approximately 3400 km/s and a velocity resolution of 200 km/s. The detectors will be a linear array of 32 close-packed monolithic silicon bolometers developed at NASA's Goddard Space Flight Center. In order to achieve background-limited sensitivity, the bolometers will be cooled to 100 mK by an adiabatic demagnetization refrigerator. The spectrometer optics will consist of a tunable cryogenic immersion grating using broadband filters as order sorters. The spectrometer will be optimized to operate in the 350 micrometer and 450 micrometer atmospheric windows. Calculations of the sensitivity of the spectrometer reveal that an ultraluminous infrared galaxy of 10(superscript 12) Lqq at a redshift of z equals 1 would be detectable at the 3(sigma) level in the C(subscript II) line with 20 minutes of integration time.

  14. Upgraded control, acquisition program and user interface for the Manchester Echelle Spectrometer at San Pedro Martir

    NASA Astrophysics Data System (ADS)

    Gutirrez, Leonel; Murillo, J.; Quiroz, Fernando; Pedrayes, Maria H.; Meaburn, John; Lpez, Jose A.

    2002-12-01

    We describe the recent upgrade of the Manchester Echelle Spectrometer, currently in use at San Pedro Mrtir. This upgrade has included a user interface and a new CCD acquisition software. The spectrometer control is now done by a microcontroller, whose inputs are new sensors and encoders installed inside the spectrometer. The instrument control is now fully carried out from a graphical user interface running in a personal computer. The acquisition computer sends the images to the GUI through an ethernet link. In this paper, we present the general scheme and the programs developed for Linux (in C++ and Tcl/Tk) that permits an easy integral operation of the instrument, as well as the creation of scripts intended to the optimization of the observing run and the future interaction with the telescope and the guider. This upgraded system has been operated successfully during several campaigns in the 2.1-meter telescope at Observatorio Astronmico Nacional in San Pedro Mrtir.

  15. Spectrometer system using a modular echelle spectrograph and a laser-driven continuum source for simultaneous multi-element determination by graphite furnace absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Geisler, Sebastian; Okruss, Michael; Becker-Ross, Helmut; Huang, Mao Dong; Esser, Norbert; Florek, Stefan

    2015-05-01

    A multi-element absorption spectrometer system has been developed based on a laser-driven xenon continuum source and a modular simultaneous echelle spectrograph (MOSES), which is characterized by a minimized number of optical components resulting in high optical throughput, high transmittance and high image quality. The main feature of the new optical design is the multifunction usage of a Littrow prism, which is attached on a rotation stage. It operates as an order-sorter for the echelle grating in a double-pass mode, as a fine positioning device moving the echelle spectrum on the detector, and as a forwarder to address different optical components, e.g., echelle gratings, in the setup. Using different prisms, which are mounted back to back on the rotation stage, a multitude of different spectroscopic modes like broad-range panorama observations, specific UV-VIS and NIR studies or high resolution zoom investigations of variable spectral channels can be realized. In the UV panorama mode applied in this work, MOSES has simultaneously detectable wavelength coverage from 193 nm to 390 nm with a spectral resolution ?/?? of 55,000 (3-pixel criterion). In the zoom mode the latter can be further increased by a factor of about two for a selectable section of the full wavelength range. The applicability and the analytical performance of the system were tested by simultaneous element determination in a graphite furnace, using eight different elements. Compared to an instrument operating in the optimized single line mode, the achieved analytical sensitivity using the panorama mode was typically a factor of two lower. Using the zoom mode for selected elements, comparable sensitivities were obtained. The results confirm the influence of the different spectral resolutions.

  16. Silicon photonics non-resonant wavelength filters: comparison between AWGs, echelle gratings, and cascaded Mach-Zehnder filters

    NASA Astrophysics Data System (ADS)

    Bogaerts, Wim; Pathak, Shibnath; Ruocco, Alfonso; Dwivedi, Sarvagya

    2015-02-01

    We present a comparison of different silicon photonics-based wavelength filters for different design criteria (e.g. channel spacing, number of channels, ...) and different performance metrics (e.g. insertion loss or crosstalk ). In this paper we compare only non-resonant filters, or finite-impulse response (FIR) filters, such as Arrayed Waveguide Gratings, Echelle Gratings and higher-order cascades of Mach-Zehnder filters. We derive the strengths and weaknesses from their operational principles and confirm those with experimental data from fabricated devices and extrapolated simulations.

  17. Compact catadioptric imaging spectrometer utilizing reflective grating

    DOEpatents

    Lerner, Scott A.

    2005-12-27

    An imaging spectrometer apparatus comprising an entrance slit for directing light, a light means for receiving the light and directing the light, a grating that receives the light from the light means and defracts the light back onto the light means which focuses the light, and a detector that receives the focused light. In one embodiment the light means is a rotationally symmetric ZNSE aspheric lens. In another embodiment the light means comprises two ZNSE aspheric lenses that are coaxial. In another embodiment the light means comprises an aspheric mirror and a ZNSE aspheric lens.

  18. Linear Fresnel Spectrometer Chip with Gradient Line Grating

    NASA Technical Reports Server (NTRS)

    Choi, Sang Hyouk (Inventor); Park, Yeonjoon (Inventor)

    2015-01-01

    A spectrometer that includes a grating that disperses light via Fresnel diffraction according to wavelength onto a sensing area that coincides with an optical axis plane of the grating. The sensing area detects the dispersed light and measures the light intensity associated with each wavelength of the light. Because the spectrometer utilizes Fresnel diffraction, it can be miniaturized and packaged as an integrated circuit.

  19. Immersion echelle spectrograph

    DOEpatents

    Stevens, Charles G.; Thomas, Norman L.

    2000-01-01

    A small spectrograph containing no moving components and capable of providing high resolution spectra of the mid-infrared region from 2 microns to 4 microns in wavelength. The resolving power of the spectrograph exceeds 20,000 throughout this region and at an optical throughput of about 10.sup.-5 cm.sup.2 sr. The spectrograph incorporates a silicon immersion echelle grating operating in high spectral order combined with a first order transmission grating in a cross-dispersing configuration to provide a two-dimensional (2-D) spectral format that is focused onto a two-dimensional infrared detector array. The spectrometer incorporates a common collimating and condensing lens assembly in a near aberration-free axially symmetric design. The spectrometer has wide use potential in addition to general research, such as monitoring atmospheric constituents for air quality, climate change, global warming, as well as monitoring exhaust fumes for smog sources or exhaust plumes for evidence of illicit drug manufacture.

  20. Study on spectrometer based upon volume holographic transmission grating

    NASA Astrophysics Data System (ADS)

    Huang, Zhen; Liu, Guodong; Ren, Zhong; Zeng, Lvming

    2010-10-01

    In this present paper, a spectrometer based upon axial transmissive optical structure with the volume-phase holographic (VPH) transmission grating technology is introduced. We give a physical insight for the structure and mechanism of photorefractive volume holographic gratings and theoretically analyze some important performance parameters of the spectrometer device using the coupled wave theory, which should be considered in the process of the following design for the device with volume phase holographic transmission gratings. The experimental results show, owing to its axial transmissive optical geometry and the perfect performance of the VPH transmission grating, the spectrometer based on the volume-phase holographic transmission grating has satisfactory high resolution and wavelength accuracy. It has great promise to be widely used in the future.

  1. Imaging Spectrometer Designs Utilizing Immersed Gratings With Accessible Entrance Slit

    DOEpatents

    Chrisp, Michael P. (Danville, CA); Lerner, Scott A. (Corvallis, OR)

    2006-03-21

    A compact imaging spectrometer comprises an entrance slit, a catadioptric lens with a mirrored surface, a grating, and a detector array. The entrance slit directs light to the mirrored surface of the catadioptric lens; the mirrored surface reflects the light back through the lens to the grating. The grating receives the light from the catadioptric lens and diffracts the light to the lens away from the mirrored surface. The lens transmits the light and focuses it onto the detector array.

  2. Modified Dyson imaging spectrometer with an aspheric grating surface

    NASA Astrophysics Data System (ADS)

    Xue, Qingsheng

    2013-11-01

    A broadband, aberration-corrected Dyson arrangement with an aspheric grating surface is proposed. An aspheric grating surface is used to correct spherical aberration resulted from the air gap between the focal plane and the rear surface of Dyson lens. The principle and the method of aberration correction are described in detail. We compare the performance of this modified Dyson arrangement with that of the Dyson arrangement using a spherical grating surface by using a practical Dyson imaging spectrometer example.

  3. Near-infrared echelle-AOTF spectrometer ACS-NIR for the ExoMars Trace Gas Orbiter

    NASA Astrophysics Data System (ADS)

    Trokhimovskiy, Alexander; Korablev, Oleg; Kalinnikov, Yurii K.; Fedorova, Anna; Stepanov, Alexander V.; Titov, Andrei Y.; Dziuban, Ilia; Patrakeev, Andrei; Montmessin, Franck

    2015-09-01

    The near-Infrared echelle-AOTF spectrometer is one channel of the Atmospheric Chemistry Suite (ACS) package dedicated for the studies of the Martian atmosphere on board ExoMars Trace Gas Orbiter planned for launch in 2016. The near-infrared (NIR) channel of ACS is a versatile spectrometer for the spectral range of 0.7-1.6 μm with a resolving power of <20,000. The NIR channel is intended to measure the atmospheric water vapor, aerosols, airglows, in nadir, in solar occultation, and on the limb. The science goals of NIR are basically the same as for SPICAM IR channel presently in flight on board Mars Express ESA orbiter, but it offers significantly better spectral resolution. The instrument employs the principle of an echelle spectrometer with an acoustooptical tunable filter (AOTF) as a preselector. The same principle was employed in SOIR, operated on Venus Express ESA mission in 2006-2014, and in RUSALKA, operated onboard ISS in 2009-2012. The NIR channel of ACS consists of entry optics, the AOTF, a Littrow echelle spectrometer, and an electrically cooled InGaAs detector array. It is a complete block with power and data interfaces, and the overall mass of 3.2 kg. The protoflight model of NIR is completed, calibrated, integrated within the ACS suite, and is undergoing tests at the spacecraft.

  4. Compact Catadioptric Imaging Spectrometer Designs Utilizing Immersed Gratings

    DOEpatents

    Lerner, Scott A. (Livermore, CA)

    2006-02-28

    An imaging spectrometer comprising an entrance slit for directing light, a lens that receives said light and reflects said light, a grating that defracts said light back onto said lens which focuses said light, and a detector array that receives said focused light. In one embodiment the grating has rulings immersed into a germanium surface.

  5. Compact echelle spectrometer for occultation sounding of the Martian atmosphere: design and performance.

    PubMed

    Korablev, Oleg; Montmessin, Franck; Trokhimovsky, Alexander; Fedorova, Anna A; Kiselev, Alexander V; Bertaux, Jean-Loup; Goultail, Jean-Pierre; Belyaev, Denis A; Stepanov, Alexander V; Titov, Andrei Yu; Kalinnikov, Yurii K

    2013-02-10

    The echelle spectrometer TIMM-2 is the instrument developed for the unsuccessful Russian mission Phobos-Grunt. The instrument was dedicated to solar occultation studies of the Martian atmosphere by measuring the amount of methane, by sensitive measuring of other minor constituents, and by profiling the D/H ratio and the aerosol structure. The spectral range of the instrument is 2300-4100 nm, the spectral resolving power ?/?? exceeds 25,000, and the field of view is 1.521 arc min. The spectra are measured in narrow spectral intervals, corresponding to discreet diffraction orders. One measurement cycle includes several spectral intervals. To study the vertical profiles of aerosol, the instrument incorporates four photometers in the UV to near-IR spectral range. The mass of the instrument is 2800 g, and its power consumption is 12 W. One complete flight model remains available after the Phobos-Grunt launch. We discuss the science objectives of the occultation experiment for the case of Mars, the implementation of the instrument, and the results of ground calibrations. PMID:23400068

  6. Hybrid plasmon photonic crystal resonance grating for integrated spectrometer biosensor.

    PubMed

    Guo, Hong; Guo, Junpeng

    2015-01-15

    Using nanofabricated hybrid metal-dielectric nanohole array photonic crystal gratings, a hybrid plasmonic optical resonance spectrometer biosensor is demonstrated. The new spectrometer sensor technique measures plasmonic optical resonance from the first-order diffraction rather than via the traditional method of measuring optical resonance from transmission. The resonance spectra measured with the new spectrometer technique are compared with the spectra measured using a commercial optical spectrometer. It is shown that the new optical resonance spectrometer can be used to measure plasmonic optical resonance that otherwise cannot be measured with a regular optical spectrometer. PMID:25679856

  7. On-sky performance of a high resolution silicon immersion grating spectrometer

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Powell, Scott; Zhao, Bo; Schofield, Sidney; Varosi, Frank; Warner, Craig; Liu, Jian; Sithajan, Sirinrat; Avner, Louis; Jakeman, Hali; Gittelmacher, Jakob A.; Yoder, William A.; Muterspaugh, Matthew; Williamson, Michael; Maxwell, J. E.

    2014-07-01

    High resolution infrared spectroscopy has been a major challenging task to accomplish in astronomy due to the enormous size and cost of IR spectrographs built with traditional gratings. A silicon immersion grating, due to its over three times high dispersion over a traditional reflective grating, offers a compact and low cost design of new generation IR high resolution spectrographs. Here we report the on-sky performance of the first silicon immersion grating spectrometer, called Florida IR Silicon immersion grating spectromeTer (FIRST), commissioned at the 2-meter Automatic Spectroscopic Telescope (AST) of Fairborn Observatory in Arizona in October 2013. The measured spectral resolution is R=50,000 with a 50 mm diameter spectrograph pupil and a blaze angle of 54.7 degree. The 1.4-1.8 ?m wavelength region (the Red channel) is completely covered in a single exposure with a 2kx2k H2RG IR array while the 0.8-1.35 ?m region is nearly completely covered by the cross-dispersed echelle mode (the Blue channel) at R=50,000 in a single exposure. The instrument is operated in a high vacuum (about 1 micro torr) and cryogenic temperatures (the bench at 189K and the detector at 87K) and with a precise temperature control. It is primarily used for high precision Doppler measurements (~3 m/s) of low mass M dwarf stars for the identification and characterization of extrasolar planets. A plan for a high cadence and high precision survey of habitable super-Earths around ~150 nearby M dwarfs and a major upgrade with integral field unit low resolution spectroscopy are also introduced.

  8. Compact Refractive Imaging Spectrometer Designs Utilizing Immersed Gratings

    DOEpatents

    Lerner, Scott A. (Livermore, CA); Bennett, Charles L. (Livermore, CA); Bixler, Jay V. (Oakland, CA); Kuzmenko, Paul J. (Livermore, CA); Lewis, Isabella T. (San Jose, CA)

    2005-07-26

    A compact imaging spectrometer comprising an entrance slit for directing light, a first means for receiving the light and focusing the light, an immersed diffraction grating that receives the light from the first means and defracts the light, a second means for receiving the light from the immersed diffraction grating and focusing the light, and an image plane that receives the light from the second means

  9. Fabrication update on critical-angle transmission gratings for soft x-ray grating spectrometers

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Bruccoleri, Alex; Mukherjee, Pran; Yam, Jonathan; Schattenburg, Mark L.

    2011-09-01

    Diffraction grating-based, wavelength dispersive high-resolution soft x-ray spectroscopy of celestial sources promises to reveal crucial data for the study of the Warm-Hot Intergalactic Medium, the Interstellar Medium, warm absorption and outflows in Active Galactic Nuclei, coronal emission from stars, and other areas of interest to the astrophysics community. Our recently developed critical-angle transmission (CAT) gratings combine the advantages of the Chandra high and medium energy transmission gratings (low mass, high tolerance of misalignments and figure errors, polarization insensitivity) with those of blazed reflection gratings (high broad band diffraction efficiency, high resolution through use of higher diffraction orders) such as the ones on XMM-Newton. Extensive instrument and system configuration studies have shown that a CAT grating-based spectrometer is an outstanding instrument capable of delivering resolving power on the order of 5,000 and high effective area, even with a telescope point-spread function on the order of many arc-seconds. We have fabricated freestanding, ultra-high aspect-ratio CAT grating bars from silicon-on-insulator wafers using both wet and dry etch processes. The 200 nm-period grating bars are supported by an integrated Level 1 support mesh, and a coarser external Level 2 support mesh. The resulting grating membrane is mounted to a frame, resulting in a grating facet. Many such facets comprise a grating array that provides light-weight coverage of large-area telescope apertures. Here we present fabrication results on the integration of CAT gratings and the different high-throughput support mesh levels and on membrane-frame bonding. We also summarize recent x-ray data analysis of 3 and 6 micron deep wet-etched CAT grating prototypes.

  10. Immersion echelle spectrograph

    SciTech Connect

    Stevens, C.G.; Thomas, N.L.

    2000-06-20

    A small spectrograph is disclosed containing no moving components and capable of providing high resolution spectra of the mid-infrared region from 2 microns to 4 microns in wavelength. The resolving power of the spectrograph exceeds 20,000 throughout this region and at an optical throughput of about 10{sup {minus}5}cm{sup 2}sr. The spectrograph incorporates a silicon immersion echelle grating operating in high spectral order combined with a first order transmission grating in a cross-dispersing configuration to provide a two-dimensional (2-D) spectral format that is focused onto a two-dimensional infrared detector array. The spectrometer incorporates a common collimating and condensing lens assembly in a near aberration-free axially symmetric design. The spectrometer has wide use potential in addition to general research, such as monitoring atmospheric constituents for air quality, climate change, global warming, as well as monitoring exhaust fumes for smog sources or exhaust plumes for evidence of illicit drug manufacture.

  11. "The Reflection Grating Spectrometer on Constellation-X"

    NASA Technical Reports Server (NTRS)

    Cottam, J.

    2006-01-01

    The Constellation-X Reflection Grating Spectrometer (RGS) is designed to provide high-throughput, high-resolution spectra in the long wavelength band of 6 to 50 angstrom. In the nominal design an array of reflection gratings is mounted at the exit of the Spectroscopy X-ray Telescope (SXT) mirror module. The gratings intercept and disperse light to a designated array of CCD detectors. To achieve the throughput (A_eff > 1000 cm2 below 0.6 keV) and resolution (R > 300 below 0.6 keV) requirements for the instrument we are investigating two possible grating designs. The first design uses in-plane gratings in a classical configuration that is very similar to the XMM-Newton RGS. The second design uses off-plane gratings in a conical configuration. The off-plane design has the advantage of providing higher reflectivity and potentially, a higher spectral resolution than the in-plane configuration. In our presentation we will describe the performance requirements and the current status of the technology development.

  12. Solar Imaging UV/EUV Spectrometers Using TVLS Gratings

    NASA Technical Reports Server (NTRS)

    Thomas, Roger J.

    2003-01-01

    It is a particular challenge to develop a stigmatic spectrograph for UV, EUV wavelengths since the very low normal-incidence reflectance of standard materials most often requires that the design be restricted to a single optical element which must simultaneously provide both reimaging and spectral dispersion. This problem has been solved in the past by the use of toroidal gratings with uniform line-spaced rulings (TULS). A number of solar extreme ultraviolet (EUV) spectrometers have been based on such designs, including SOHO/CDS, Solar-B/EIS, and the sounding rockets Solar Extreme ultraviolet Research Telescope and Spectrograph (SERTS) and Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS). More recently, Kita, Harada, and collaborators have developed the theory of spherical gratings with varied line-space rulings (SVLS) operated at unity magnification, which have been flown on several astronomical satellite missions. We now combine these ideas into a spectrometer concept that puts varied-line space rulings onto toroidal gratings. Such TVLS designs are found to provide excellent imaging even at very large spectrograph magnifications and beam-speeds, permitting extremely high-quality performance in remarkably compact instrument packages. Optical characteristics of three new solar spectrometers based on this concept are described: SUMI and RAISE, two sounding rocket payloads, and NEXUS, currently being proposed as a Small-Explorer (SMEX) mission.

  13. Design of a hybrid-integrated MEMS scanning grating spectrometer

    NASA Astrophysics Data System (ADS)

    Pügner, Tino; Knobbe, Jens; Grüger, Heinrich; Schenk, Harald

    2011-10-01

    Optical MEMS (micro electro mechanical systems) have been used to reduce size, weight and costs of any kind of optical systems very successfully starting in the last decades. Scientists at Fraunhofer IPMS invented a resonant drive for 1-d and 2-d MEMS scanning mirror devices. Besides mirrors also scanning gratings have been realized. Now, rapidly growing new applications demand for enhanced functions and further miniaturization. This task cannot be solved by simply putting more functionality into the MEMS chip, for example grating and slit structures, but by three dimensional hybrid integration of the complete optical system into a stack of several functional substrates. Here we present the optical system design and realization strategy for a scanning grating spectrometer for the near infrared (NIR) range. First samples will be mounted from single components by a bonder tool (Finetech Fineplacer Femto) but the option of wafer assembly will be kept open for future developments. Extremely miniaturized NIR spectrometer could serve a wide variety of applications for handheld devices from food quality analysis to medical services or materials identification.

  14. System design of multi-function grating spectrometer

    NASA Astrophysics Data System (ADS)

    Sui, Cheng-hua; Xu, Dan-yang; Tong, Jian-ping; Yang, Yang

    2010-10-01

    A multi-function grating spectrometer is introduced, which is composed of grating monochromator, signal receiving units, electronic amplifiers, A/D converter, computer, matching illuminant and so on. This equipment is a complex technique related to optics, precision machinery, electronics and computer. CCD and optical grating is used that break the limitation of photomultiplier (PMT). The CCD can receive signals in the spatial distribution. The efficiency of full spectrum detection is greatly raised. With the way of DMA block move and adopting high-speed A/D AD1674JN it realizes high-speed data acquisition. The principles of system working, hardware circuit, logic of controlling are described in detail. The spectrometer has two kinds of measurement range, the CCD can measure the spectrum wave from 300 nm~600 nm, and the photomultiplier (PMT) can measure the spectrum wave from 200 nm~660 nm. Controlling a Step Motor that cooperating with a deceleration system, and using the C-T optical system, in theory, moving 0.01 nm can catch a spectral pulse, the resolution can reach 0.06 nm.

  15. Development of a Submillimeter-Wavelength Immersion Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Phillips, T. G.

    2001-01-01

    The broad goal of this project was to develop a broadband, moderate-resolution spectrometer for submillimeter wavelengths. Our original approach was to build an immersion grating spectrometer, and as such, the first step was to identify the best material (lowest loss, highest index) for the grating medium, and to characterize its properties at the foreseen optical-bench operating temperature of 1.5 K. To this end, we put our initial efforts into upgrading an existing laboratory submillimeter Fourier transform spectrometer, which allowed us to carry out the requisite materials measurements. The associated cryogenic detector dewar was also redesigned and rebuilt to carry out this work. This dewar houses the 1.5 K detector and the filter wheel used in the materials characterization. Our goal was to have the beam propagate through the samples as uniformly as possible, so the optics were redesigned to allow for the samples to be traversed by a well-defined collimated beam. The optics redesign also placed the samples at an image of the aperture stop located within the FTS. After the rebuild, we moved into the testing phase.

  16. Design and early performance of IGRINS (Immersion Grating Infrared Spectrometer)

    NASA Astrophysics Data System (ADS)

    Park, Chan; Jaffe, Daniel T.; Yuk, In-Soo; Chun, Moo-Young; Pak, Soojong; Kim, Kang-Min; Pavel, Michael; Lee, Hanshin; Oh, Heeyoung; Jeong, Ueejeong; Sim, Chae Kyung; Lee, Hye-In; Nguyen Le, Huynh Anh; Strubhar, Joseph; Gully-Santiago, Michael; Oh, Jae Sok; Cha, Sang-Mok; Moon, Bongkon; Park, Kwijong; Brooks, Cynthia; Ko, Kyeongyeon; Han, Jeong-Yeol; Nah, Jakyoung; Hill, Peter C.; Lee, Sungho; Barnes, Stuart; Yu, Young Sam; Kaplan, Kyle; Mace, Gregory; Kim, Hwihyun; Lee, Jae-Joon; Hwang, Narae; Park, Byeong-Gon

    2014-07-01

    The Immersion Grating Infrared Spectrometer (IGRINS) is a compact high-resolution near-infrared cross-dispersed spectrograph whose primary disperser is a silicon immersion grating. IGRINS covers the entire portion of the wavelength range between 1.45 and 2.45μm that is accessible from the ground and does so in a single exposure with a resolving power of 40,000. Individual volume phase holographic (VPH) gratings serve as cross-dispersing elements for separate spectrograph arms covering the H and K bands. On the 2.7m Harlan J. Smith telescope at the McDonald Observatory, the slit size is 1ʺ x 15ʺ and the plate scale is 0.27ʺ pixel. The spectrograph employs two 2048 x 2048 pixel Teledyne Scientific and Imaging HAWAII-2RG detectors with SIDECAR ASIC cryogenic controllers. The instrument includes four subsystems; a calibration unit, an input relay optics module, a slit-viewing camera, and nearly identical H and K spectrograph modules. The use of a silicon immersion grating and a compact white pupil design allows the spectrograph collimated beam size to be only 25mm, which permits a moderately sized (0.96m x 0.6m x 0.38m) rectangular cryostat to contain the entire spectrograph. The fabrication and assembly of the optical and mechanical components were completed in 2013. We describe the major design characteristics of the instrument including the system requirements and the technical strategy to meet them. We also present early performance test results obtained from the commissioning runs at the McDonald Observatory.

  17. Modified tandem gratings anastigmatic imaging spectrometer with oblique incidence for spectral broadband

    NASA Astrophysics Data System (ADS)

    Cui, Chengguang; Wang, Shurong; Huang, Yu; Xue, Qingsheng; Li, Bo; Yu, Lei

    2015-09-01

    A modified spectrometer with tandem gratings that exhibits high spectral resolution and imaging quality for solar observation, monitoring, and understanding of coastal ocean processes is presented in this study. Spectral broadband anastigmatic imaging condition, spectral resolution, and initial optical structure are obtained based on geometric aberration theory. Compared with conventional tandem gratings spectrometers, this modified design permits flexibility in selecting gratings. A detailed discussion of the optical design and optical performance of an ultraviolet spectrometer with tandem gratings is also included to explain the advantage of oblique incidence for spectral broadband.

  18. Initial Results From The Chandra High Energy Transmission Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Canizares, C. R.; Davis, D. S.; Dewey, D.; Flanagan, K. A.; Houck, J.; Huenemoerder, D. P.; Marshall, H. L.; Schattenburg, M. L.; Schulz, N. S.; Wise, M.

    2000-01-01

    The High Energy Transmission Grating Spectrometer (HETGS) on the Chandra X-ray Observatory provides spectral resolving powers of 200-1000 over the range 0.4-8.0 keV (1.5-30 A) with effective area of 2-200 square centimeters. Initial observations during the activation and calibration phases of the mission show that the HETGS is performing as predicted prior to Chandra launch. The talk presented very preliminary results that illustrate the power of the HETGS for performing detailed studies of a wide range of celestial sources, including plasma diagnostics. This written version gives a brief summary of that talk with examples of preliminary spectra of Capella, the Crab pulsar, SS433 and the SNR E0102-72.

  19. The Reflection Grating Spectrometer on Board XMM-Newton

    NASA Technical Reports Server (NTRS)

    denHerder, J. W.; Brinkman, A. C.; Kahn, S. M.; Branduardi-Raymont, G.; Thomsen, K.; Aarts, H.; Audard, M.; Bixler, J. V.; denBoggende, A. J.

    2000-01-01

    The ESA X-ray Multi Mirror mission, XMM-Newton, carries two identical Reflection Grating Spectrometers (RGS) behind two of its three nested sets of Wolter I type mirrors. The instrument allows high-resolution (E/(Delta)E = 100 to 500) measurements in the soft X-ray range (6 to 38 A or 2.1 to 0.3 keV) with a maximum effective area of about 140 sq cm at 15 A. Its design is optimized for the detection of the K-shell transitions of carbon, nitrogen, oxygen, neon, magnesium, and silicon. as well as the L shell transitions of iron. The present paper gives a full description of the design of the RGS and its operational modes. We also review details of the calibrations and in-orbit performance including the line spread function, the wavelength calibration, the effective area, and the instrumental background.

  20. Next Generation Grating Spectrometer Sounders for LEO and GEO

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.

    2011-01-01

    AIRS and MODIS are widely used for weather, climate, composition, carbon cycle, cross-calibration, and applications. The community asking for new capability in the 2020 timeframe, capabilities desired: (1) Hyperspectral UV to LWIR, High Spatial ?1km IFOV (2) Maximize Synergies of Solar Reflected and IR. Synergies with OCO-2. We expect more users and applications of next gen LEO IR Sounder than GEO. These include: weather, climate, GHG monitoring, aviation, disaster response. There is a new direction for imagers and sounders: (1) Separate Vis/NIR/SWIR from MWIR/LWIR instruments reduces technology risk and complexity. (2) Expect Costs to be lower than CrIS & VIIRS Some additional ideas to reduce costs include: (1) minimum set of requirements (2) mini-grating spectrometers. supports constellation for higher revisit (3) new technology to reduce instrument size (large format fpa's) (4) hosted payloads

  1. A simple scanning spectrometer based on a stretchable elastomeric reflective grating

    SciTech Connect

    Ghisleri, C.; Milani, P.; Potenza, M. A. C.; Bellacicca, A.; Ravagnan, L.

    2014-02-10

    We report a scanning optical spectrometer based on the use of a stretchable elastomeric reflective grating. The grating is obtained by supersonic cluster beam implantation of silver nanoparticles on polydimethylsiloxane previously grooved by molding to create a replica of a commercial digital versatile disk grating. The use of a stretchable grating allows the spectrometer spanning the whole optical wavelength range by solely extending the diffraction element by more than 100% of its original dimensions. The stretchable reflective optical grating shows excellent performances and stability upon thousands of stretching cycles. The use of this elastomeric element makes the optical layout and the mechanics of the spectrometer extremely simple and advantageous for those applications where spectral resolution is not a major requirement. As a proof of principle, we present the absorption spectrum of Rhodamine B in solution obtained by our spectrometer and compared to commercial instruments.

  2. InGaAs/InP-based Echelle mirror multiplexer using dual Rowland circle gratings for DFB QCL arrays in the mid-long infrared range

    NASA Astrophysics Data System (ADS)

    Orbe, L. J.; Gordon, C.; Carpintero, G.; Maisons, G.; Carras, M.

    2014-02-01

    In this work we introduce the design, optimization, simulation and experimental characterization results of a 30-to-1 wavelength multiplexer for a Distributed Feedback Quantum Cascade Laser (DFB QCL) laser array operating in the 7- 8.5 ?m (mid-long) infrared (IR) range based on an Echelle mirror using a dual Rowland circle grating scheme. This design is proposed in order to achieve a continuous tuning range overcoming the limited tunability of individual QCLs. The design is based on a DFB-QCL array with wavelength spacing of 0.05 ?m, aiming to reducing coupling between the slab waveguides to a minimum. We discuss the design parameters such as the order of diffraction, the operation wavelength range in the slab waveguides and the position of both the input and output waveguides are optimized for obtaining higher output power in the overall wavelength range of the multiplexer device than in a single Rowland circle grating scheme, providing an improvement in channel transmission. Other design characteristics, such as the structure scalability and reduction in size for these devices are considered and studied, including the input/output waveguide optimization as a function of parameters such as waveguide width, etching depth and wavelength. A systematic process is presented for all steps in the design of these devices, comparing both simulated and experimental results, placing them as suitable options when compared to other IR multiplexer schemes in terms of size and transmission.

  3. [Technology Development for X-Ray Reflection for the Constellation-X Reflection Grating Spectrometer (RGS)

    NASA Technical Reports Server (NTRS)

    Schattenburg, Mark L.

    2003-01-01

    This Grant covers MIT support for the technology development of x-ray reflection gratings for the Constellation-X Reflection Grating Spectrometer (RGS). Since the start of the Grant MIT has extended its previously-developed patterning and super-smooth, blazed grating fabrication technology to ten-times smaller grating periods and ten-times larger blaze angles to demonstrate feasibility and performance in the off-plane grating geometry. In the past year we successfully developed several nanoimprint grating replication methods that achieved very high fidelity replication of master silicon gratings. Grating geometry on the nano and macro scales were faithfully replicated, demonstrating the viability of the process for manufacturing the thousands of gratings required for the RGS. We also successfully developed an improved metrology truss for holding test grating substrates during metrology. The flatness goal of grating substrates is under 500 nm. In the past, grating holders would cause non-repeatable distortion of >> 500 nm to the substrates due to friction and gravity sag. The new holder has a repeatability of under 50 nm which is adequate for the proposed RGS grating substrates.

  4. High resolution Florida IR silicon immersion grating spectrometer and an M dwarf planet survey

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Powell, Scott; Zhao, Bo; Wang, Ji; Fletcher, Adam; Schofield, Sidney; Liu, Jian; Muterspaugh, Matthew; Blake, Cullen; Barnes, Rory

    2012-09-01

    We report the system design and predicted performance of the Florida IR Silicon immersion grating spectromeTer (FIRST). This new generation cryogenic IR spectrograph offers broad-band high resolution IR spectroscopy with R=72,000 at 1.4-1.8 ?m and R=60,000 at 0.8-1.35 ?m in a single exposure with a 2kx2k H2RG IR array. It is enabled by a compact design using an extremely high dispersion silicon immersion grating (SIG) and an R4 echelle with a 50 mm diameter pupil in combination with an Image Slicer. This instrument is operated in vacuum with temperature precisely controlled to reach long term stability for high precision radial velocity (RV) measurements of nearby stars, especially M dwarfs and young stars. The primary technical goal is to reach better than 4 m/s long term RV precision with J<9 M dwarfs within 30 min exposures. This instrument is scheduled to be commissioned at the Tennessee State University (TSU) 2-m Automatic Spectroscopic Telescope (AST) at Fairborn Observatory in spring 2013. FIRST can also be used for observing transiting planets, young stellar objects (YSOs), magnetic fields, binaries, brown dwarfs (BDs), ISM and stars. We plan to launch the FIRST NIR M dwarf planet survey in 2014 after FIRST is commissioned at the AST. This NIR M dwarf survey is the first large-scale NIR high precision Doppler survey dedicated to detecting and characterizing planets around 215 nearby M dwarfs with J< 10. Our primary science goal is to look for habitable Super-Earths around the late M dwarfs and also to identify transiting systems for follow-up observations with JWST to measure the planetary atmospheric compositions and study their habitability. Our secondary science goal is to detect and characterize a large number of planets around M dwarfs to understand the statistics of planet populations around these low mass stars and constrain planet formation and evolution models. Our survey baseline is expected to detect ~30 exoplanets, including 10 Super Earths, within 100 day periods. About half of the Super-Earths are in their habitable zones and one of them may be a transiting planet. The AST, with its robotic control and ease of switching between instruments (in seconds), enables great flexibility and efficiency, and enables an optimal strategy, in terms of schedule and cadence, for this NIR M dwarf planet survey.

  5. A Soft X-ray Spectrometer using a Highly Dispersive Multilayer Grating

    SciTech Connect

    Warwick, Tony; Padmore, Howard; Voronov, Dmitriy; Yashchuk, Valeriy

    2010-01-31

    There is a need for higher resolution spectrometers as a tool for inelastic x-ray scattering. Currently, resolving power around R = 10,000 is advertised. Measured RIXS spectra are often limited by this instrumental resolution and higher resolution spectrometers using conventional gratings would be prohibitively large. We are engaged in a development program to build blazed multilayer grating structures for diffracting soft x-rays in high order. This leads to spectrometers with dispersion much higher than is possible using metal coated-gratings. The higher dispersion then provides higher resolution and the multilayer gratings are capable of operating away from grazing incidence as required. A spectrometer design is presented with a total length 3.8m and capable of 10{sup 5} resolving power.

  6. A Soft X-ray Spectrometer using a Highly Dispersive Multilayer Grating

    SciTech Connect

    Warwick, Tony; Padmore, Howard; Voronov, Dmitriy; Yashchuk, Valeriy

    2010-06-23

    There is a need for higher resolution spectrometers as a tool for inelastic x-ray scattering. Currently, resolving power around R = 10,000 is advertised. Measured RIXS spectra are often limited by this instrumental resolution and higher resolution spectrometers using conventional gratings would be prohibitively large. We are engaged in a development program to build blazed multilayer grating structures for diffracting soft x-rays in high order. This leads to spectrometers with dispersion much higher than is possible using metal coated-gratings. The higher dispersion then provides higher resolution and the multilayer gratings are capable of operating away from grazing incidence as required. A spectrometer design is presented with a total length 3.8 m and capable of 10{sup 5} resolving power.

  7. Compact Reflective Imaging Spectrometer Design Utilizing An Immersed Grating And Anamorphic Mirror

    DOEpatents

    Lerner, Scott A. (Corvalis, OR)

    2006-01-10

    A compact imaging spectrometer comprising an entrance slit, an anamorphic mirror, a grating, and a detector array. The entrance slit directs light to the anamorphic mirror. The anamorphic mirror receives the light and directs the light to the grating. The grating receives the light from the anamorphic mirror and defracts the light back onto the anamorphic mirror. The anamorphic mirror focuses the light onto a detector array.

  8. Design and experiment of spectrometer based on scanning micro-grating integrating with angle sensor

    NASA Astrophysics Data System (ADS)

    Biao, Luo; Wen, Zhi-yu

    2014-01-01

    A compact, low cost, high speed, non-destructive testing NIR (near infrared) spectrometer optical system based on MOEMS grating device is developed. The MOEMS grating works as the prismatic element and wavelength scanning element in our optical system. The MOEMS grating enables the design of compact grating spectrometers capable of acquiring full spectra using a single detector element. This MOEMS grating is driven by electromagnetic force and integrated with angle sensor which used to monitored deflection angle while the grating working. Comparing with the traditional spectral system, there is a new structure with a single detector and worked at high frequency. With the characteristics of MOEMS grating, the structure of the spectrometer system is proposed. After calculating the parameters of the optical path, ZEMAX optical software is used to simulate the system. According the ZEMAX output file of the 3D model, the prototype is designed by SolidWorks rapidly, fabricated. Designed for a wavelength range between 800 nm and 1500 nm, the spectrometer optical system features a spectral resolution of 16 nm with the volume of 97 mm 81.7 mm 81 mm. For the purpose of reduce modulated effect of sinusoidal rotation, spectral intensity of the different wavelength should be compensated by software method in the further. The system satisfies the demand of NIR micro-spectrometer with a single detector.

  9. ELOIS: an innovative spectrometer design using a free-form grating

    NASA Astrophysics Data System (ADS)

    De Clercq, Coralie; Moreau, Vincent; Jamoye, Jean-François; Zuccaro Marchi, Alessandro; Gloesener, Pierre

    2015-09-01

    For spaceborne hyperspectral applications1, grating-based spectrometers are of special interest due to the high spectral resolution and optical throughput that can be achieved. The classical spectrometer designs are 1:1 systems. For these systems the achievable signal to noise ratio is limited by the slit width/pixel pitch combination. One way to increase the signal to noise ratio of a spectrometer without increasing the global instrument size is to design an instrument with a magnification power of less than one. With a smaller magnification, the entrance slit is wider and a larger amount of light is collected while the image is smaller and compatible with typical detector size and pixel pitch. We presents an innovative spectrometer design with 2:1 magnification and high image quality and radiometric performances. This spectrometer called ELOIS (for Enhanced Light Offner Imaging Spectrometer) is designed with a grating atop a free-form surface. The use non-rotationally symmetric surfaces offer additional freedom for designing compact and well-corrected instruments. Nevertheless, most of the available manufacturing techniques, such as direct ruling, holography, lithography or e-beam writing, are typically applicable on simple shape of the grating surface, such as flat or spherical surface. AMOS demonstrated the feasibility of the Free Form Grating (FFG), i.e. a ruled grating on a surface without any rotational symmetry, using cost-effective approach for manufacturing blazed grating by Single Point Diamond Turning (SPDT).

  10. Design of optical system for spectrometer involving a volume phase holographic transmission grating

    NASA Astrophysics Data System (ADS)

    Ren, Zhong; Liu, Guodong; Huang, Zhen

    2014-08-01

    At present, spectrometer has popularly being used into varieties of fields including environment, food, medical health monitoring and metal industry because it has the advantages of noninvasive, high efficient and convenient etc. The performance of the spectrometer is determined by its optical system. Normally, according to the apparatus and principle of splitting-light, optical system of spectrometer can be classified into several categories, for example, filter-typed, dispersion typed, Fourier transform typed and acousto-optic tunable typed. The grating typed optical system has been popularly used into the spectrometer due to the features of higher diffraction efficiency, resolution and dispersion rate etc. In the grating-typed optical system, although the traditional plane and concave grating have usually been used into some spectrometers, some disadvantages of them still limit their applications, such as, large aberration, worse spectral flatness and low deficiency, etc. In this paper, to overcome these disadvantages of the traditional plane and concave grating, a novel optical system for spectrometer (OSS) based on volume phase holographic transmission (VPHT) grating was designed. For this novel grating, its manufacture and theories were investigated, and its diffraction efficiency was firstly numerically simulated according to different parameters. In order to prove the feasibility of this designed OSS, the spectral calibration experiment was performed and the spectral resolution reached 2nm.

  11. A rotated transmission grating spectrometer for detecting spectral separation of doublet Na

    SciTech Connect

    Santosa, Ignatius Edi

    2015-04-16

    Transmission gratings are usually used in a spectrometer for measuring the wavelength of light. In the common design, the position of the grating is perpendicular to the incident light. In order to increase the angular dispersion, in contrary to the common design, in this experiment the transmission grating was rotated. Due to the non-zero incident angle, the diffracted light was shifted. This rotated transmission grating spectrometer has been used to determine the separation of doublet Na. In this experiment, the diffraction angle was measured at various incident angles. The spectral separation of doublet Na was identified from the difference in the diffraction angle of two spectral lines. This spectral separation depends on the incident angle, the grating constant and the order of diffraction. As the effect of increasing the incident angle, a significant increase of the spectral separation can be achieved up to three fold.

  12. Passive Spectroscopy Bolometers, Grating- And X-Ray Imaging Crystal Spectrometers

    SciTech Connect

    Bitter, M; Hill, K W; Scott, S; Paul, S; Ince-Cushmann, A; Reinke, M; Rice, J; Beiersdorfer, P; Gu, M F; Lee, S G; Broennimann, C; Eikenberry, E F

    2007-11-07

    This tutorial gives a brief introduction into passive spectroscopy and describes the working principles of bolometers, a high-resolution grating spectrometer, and a novel X-ray imaging crystal spectrometer, which is of particular interest for profile measurements of the ion temperature and plasma rotation velocity on ITER and future burning plasma experiments.

  13. Soft x-ray blazed transmission grating spectrometer with high resolving power and extended bandpass

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Bruccoleri, Alexander Robert; Schattenburg, Mark

    2015-04-01

    A number of high priority questions in astrophysics can be addressed by a state-of-the-art soft x-ray grating spectrometer, such as the role of Active Galactic Nuclei in galaxy and star formation, characterization of the Warm-Hot Intergalactic Medium and the “missing baryon” problem, characterization of halos around the Milky Way and nearby galaxies, as well as stellar coronae and surrounding winds and disks. An Explorer-scale, large-area (> 1,000 cm2), high resolving power (R = λ/Δλ > 3,000) soft x-ray grating spectrometer is highly feasible based on Critical-Angle Transmission (CAT) grating technology. Still significantly higher performance can be provided by a CAT grating spectrometer on an X-ray-Surveyor-type mission. CAT gratings combine the advantages of blazed reflection gratings (high efficiency, use of higher diffraction orders) with those of conventional transmission gratings (low mass, relaxed alignment tolerances and temperature requirements, transparent at higher energies) with minimal mission resource requirements. They are high-efficiency blazed transmission gratings that consist of freestanding, ultra-high aspect-ratio grating bars fabricated from silicon-on-insulator (SOI) wafers using advanced anisotropic dry and wet etch techniques. Blazing is achieved through grazing-incidence reflection off the smooth grating bar sidewalls. The reflection properties of silicon are well matched to the soft x-ray band. Nevertheless, CAT gratings with sidewalls made of higher atomic number elements allow extension of the CAT grating principle to higher energies and larger dispersion angles. We show x-ray data from metal-coated CAT gratings and demonstrate efficient blazing to higher energies and larger blaze angles than possible with silicon alone. We also report on measurements of the resolving power of a breadboard CAT grating spectrometer consisting of a Wolter-I slumped-glass focusing mirror pair from Goddard Space Flight Center and CAT gratings, to be performed at the Marshall Space Flight Center Stray Light Facility.

  14. Development of immersed diffraction grating for the TROPOMI-SWIR spectrometer

    NASA Astrophysics Data System (ADS)

    van Amerongen, A. H.; Visser, H.; Vink, R. J. P.; Coppens, T.; Hoogeveen, R. W. M.

    2010-10-01

    We have developed a novel diffraction grating based on lithographical techniques and anisotropic etching in silicon. The grating is designed for the short-wave-infrared channel of the TROPOMI imaging spectrometer that will be launched on ESA's Sentinel 5 Precursor mission to monitor trace gases in the earth atmosphere. Stringent requirements on both the imaging properties and the quality of the spectra translate to a high-tech grating. In our design the dispersion and resolution is increased with a factor 3.4 with respect to conventional gratings by using the grating in immersion, such that diffraction takes place inside the silicon grating material. By lithographic patterning and anisotropic etching of the mono-crystalline silicon we precisely control line spacing and blaze angle. The grating has a line spacing of 2.5 ?m and is operated in sixth order. We show that an efficiency of 60% is reached on a 50 x 60 mm2 grating surface. We compare our test results with numerical calculations for grating efficiency for both polarizations and find good agreement.

  15. Development, fabrication, and metrology of the electro-optical breadboard model for the reflection grating array of the XMM grating spectrometer

    SciTech Connect

    Decker, T.A.; Montesanti, R.C.; Bixler, J.V.; Hailey, C.J.; Kahn, S.M. |

    1994-07-01

    A prototype array consisting of eight diffraction gratings has been fabricated for the XMM Reflection Grating Spectrometer. A component of the full spectrometer is an array of approximately 200 diffraction gratings. The diffraction gratings were produced using lightweight silicon carbide substrates and a replication technique. The prototype array was developed and assembled using the same tolerances as the flight arrays which have typical tolerances of 3 {mu}m in translation and sub-arc seconds in rotation. The metrology applied during inspection and assembly included precision linear measurements, full aperture figure measurements, and angular interferometry.

  16. Imaging extreme ultraviolet spectrometer employing a single toroidal diffraction grating: the initial evaluation.

    PubMed

    Huber, M C; Timothy, J G; Morgan, J S; Lemaitre, G; Tondello, G; Jannitti, E; Scarin, P

    1988-08-15

    A high-efficiency extreme ultraviolet (EUV) imaging spectrometer has been constructed and tested. The spectrometer employs a concave toroidal grating illuminated at normal incidence in a Rowland circle mounting and has only one reflecting surface. The toroidal grating has been fabricated by a new technique employing an elastically deformable submaster grating which is replicated in a spherical form and then mechanically distorted to produce the desired aspect ratio of the toroidal surface for stigmatic imaging over the selected wavelength range. The fixed toroidal grating used in the spectrometer is then replicated from this surface. Photographic tests and initial photoelectric tests with a 2-D pulse-counting detector system have verified the image quality of the toroidal grating at wavelengths near 600 A. The results of these initial tests are described in detail, and the basic designs of two instruments which could employ the imaging spectrometer for astrophysical investigations in space are briefly described, namely, a high-resolution EUV spectroheliometer for studies of the solar chromosphere, transition region, and corona and an EUV spectroscopic telescope for studies of nonsolar objects. PMID:20539406

  17. The high-resolution cross-dispersed echelle white-pupil spectrometer of the McDonald Observatory 2.7-m telescope

    NASA Technical Reports Server (NTRS)

    Tull, Robert G.; Macqueen, Phillip J.; Sneden, Christopher; Lambert, David L.

    1995-01-01

    A new high-resolution cross-dispersed echelle spectrometer has been installed at the coude focus of the McDonald Observatory 2.7-m telescope. Its primary goal was simultaneously to gather spectra over as much of the spectral range 3400 A to 1 micrometer as practical, at a resolution R identical with lambda/Delta lambda which approximately = 60,000 with signal-to-noise ratio of approximately 100 for stars down to magnitude 11, using 1-h exposures. In the instrument as built, two exposures are all that are needed to cover the full range. Featuring a white-pupil design, fused silica prism cross disperser, and folded Schmidt camera with a Tektronix 2048x2048 CCD used at either of two foci, it has been in regularly scheduled operation since 1992 April. Design details and performance are described.

  18. Imaging extreme ultraviolet spectrometer employing a single toroidal diffraction grating - The initial evaluation

    NASA Technical Reports Server (NTRS)

    Huber, M. C. E.; Timothy, J. G.; Morgan, J. S.; Lemaitre, G.; Tondello, G.

    1988-01-01

    The design and test results of a high-efficiency EUV imaging spectrometer employing a concave toroidal grating which is illuminated at normal incidence in a Rowland circle mounting and has only one reflecting surface are discussed. Photographic tests and initial photoelectric tests with a two-dimensional pulse-counting detector system demonstrate the excellent image quality of the grating at wavelengths near 600 A. Applications of the spectrometer for the study of nonsolar objects and solar regions (including the chromosphere, transition region, and corona) are considered.

  19. [Study on far ultraviolet imaging spectrometer with grating dispersion for atmosphere remote sensing].

    PubMed

    Yu, Lei; Wang, Shu-rong; Lin, Guan-yu; Qu, Yi; Wang, Long-qi

    2012-03-01

    The far ultraviolet imaging spectrometer with grating dispersion is mainly used in the detection of the ionosphere, thermosphere, auroral zone and glow zone. It is important for the study and application of the remote sensing of atmosphere in China. We designed two optical systems for the far ultraviolet imaging spectrometer, and obtained the plane grating structure prototype based on the principles of nadir and limb atmospheric sounding. The prototype working at the waveband of 120-180 nm consists of an off-axis parabolic mirror and an advanced Czerny-Turner spectral imaging system. The far ultraviolet response back-illuminating CCD is adopted as the detector. The corresponding experiment system was built to calibrate the basic performances of the spectrometer prototype. The spectral and spatial resolutions are 2 nm and 0.5 mrad respectively. The far ultraviolet imaging spectrometer prototype plays an important role in the study and application of atmospheric remote sensing. PMID:22582666

  20. Transmission grating based extreme ultraviolet imaging spectrometer for time and space resolved impurity measurements

    SciTech Connect

    Kumar, Deepak; Stutman, Dan; Tritz, Kevin; Finkenthal, Michael; Tarrio, Charles; Grantham, Steven

    2010-10-15

    A free standing transmission grating based imaging spectrometer in the extreme ultraviolet range has been developed for the National Spherical Torus Experiment (NSTX). The spectrometer operates in a survey mode covering the approximate spectral range from 30 to 700 A and has a resolving capability of {delta}{lambda}/{lambda} on the order of 3%. Initial results from space resolved impurity measurements from NSTX are described in this paper.

  1. Study of Planck's Law with a Small USB Grating Spectrometer

    ERIC Educational Resources Information Center

    Navratil, Zdenek; Dosoudilova, Lenka; Jurmanova, Jana

    2013-01-01

    In this paper an experiment to study Planck's radiation law is presented. The spectra of a heated furnace and of a halogen lamp under various conditions were measured with a small USB grating spectrometer and fitted using Planck's law. The temperature determined from the fit was then compared with the results of comparative temperature

  2. Study of Planck's Law with a Small USB Grating Spectrometer

    ERIC Educational Resources Information Center

    Navratil, Zdenek; Dosoudilova, Lenka; Jurmanova, Jana

    2013-01-01

    In this paper an experiment to study Planck's radiation law is presented. The spectra of a heated furnace and of a halogen lamp under various conditions were measured with a small USB grating spectrometer and fitted using Planck's law. The temperature determined from the fit was then compared with the results of comparative temperature…

  3. Design and fabrication of an active polynomial grating for soft-X-ray monochromators and spectrometers

    NASA Astrophysics Data System (ADS)

    Chen, S.-J.; Chen, C. T.; Perng, S. Y.; Kuan, C. K.; Tseng, T. C.; Wang, D. J.

    2001-07-01

    An active polynomial grating has been designed for use in synchrotron radiation soft-X-ray monochromators and spectrometers. The grating can be dynamically adjusted to obtain the third-order-polynomial surface needed to eliminate the defocus and coma aberrations at any photon energy. Ray-tracing results confirm that a monochromator or spectrometer based on this active grating has nearly no aberration limit to the overall spectral resolution in the entire soft-X-ray region. The grating substrate is made of a precisely milled 17-4 PH stainless steel parallel plate, which is joined to a flexure-hinge bender shaped by wire electrical discharge machining. The substrate is grounded into a concave cylindrical shape with a nominal radius and then polished to achieve a roughness of 0.45 nm and a slope error of 1.2 ?rad rms. The long trace profiler measurements show that the active grating can reach the desired third-order polynomial with a high degree of figure accuracy.

  4. The Off-Plane X-ray Grating Spectrometer for the International X-ray Observatory

    NASA Astrophysics Data System (ADS)

    Casement, L. Suzanne; Johnson, T. P.; Lillie, C.; McEntaffer, R.; Cash, W.

    2010-01-01

    The baseline configuration for the International X-ray Observatory (IXO) includes a soft x-ray grating spectrometer as part of its instrument complement to provide a spectral resolution of R >3000 over the 0.3 - 1 keV band with >1000 cm2 effective collecting area. An Off-Plane X-ray Grating Spectrometer (OP-XGS) is being proposed to the project to meet this need, using experience gained with the current generation of reflection gratings already flown on rocket experiments. These rocket experiments have demonstrated R of >100 with wire grid collimators and objective gratings that produce large point spread functions. Prototype gratings fabricated for the IXO project have achieved adequate throughput to obtain the IXO effective area requirement while resolution tests have demonstrated ?/?? > 200 when used with a 3 arc minute (angular resolution) telescope. When combined with the IXO telescope performance, the resulting spectral resolution is well over the IXO requirement. The conceptual design, two trade options, and predicted performance of this system is presented here, along with the technology developments that will be needed to achieve the desired performance.

  5. The Off-Plane X-ray Grating Spectrometer for the International X-ray Observatory

    NASA Astrophysics Data System (ADS)

    Casement, Suzanne; Johnson, T.; Lillie, C.; McEntaffer, R.; Cash, W.

    2009-09-01

    The baseline configuration for the International X-ray Observatory (IXO) includes a soft x-ray grating spectrometer as part of its instrument complement to provide a spectral resolution of R >3000 over the 0.3 - 1 keV band with >1000 square cm effective collecting area. Using the current generation of reflection gratings flown on rocket experiments as a point of departure, an Off-Plane X-ray Grating Spectrometer (OP-XGS) is being proposed to the project to meet this need. These rocket experiments have demonstrated R of >100 with wire grid collimators and objective gratings that produce large point spread functions. Prototype gratings fabricated for the IXO project have achieved adequate throughput to obtain the IXO effective area requirement while resolution tests have demonstrated ?/?? > 200 when used with a 3 arc minute (angular resolution) telescope. When combined with the IXO telescope performance, the resulting spectral resolution is well over the IXO requirement. The OP-XGS will thus provide higher spectral resolution (over a slightly smaller energy range) than the Chandra LETGS instrument but with a larger effective collecting area providing improved sensitivity. The conceptual design and predicted performance of this system is presented here, along with the technology developments that will be needed to achieve the desired performance.

  6. Varied-space grazing incidence gratings in high resolution scanning spectrometers

    SciTech Connect

    Hettrick, M.C.; Underwood, J.H.

    1986-10-01

    We discuss the dominant geometrical aberrations of a grazing incidence reflection grating and new techniques which can be used to reduce or eliminate them. Convergent beam geometries and the aberration correction possible with varied groove spacings are each found to improve the spectral resolution and speed of grazing incidence gratings. In combination, these two techniques can result in a high resolution (lambda/..delta..lambda > 10/sup 4/) monochromator or scanning spectrometer with a simple rotational motion for scanning wavelength or selecting the spectral band. 21 refs., 4 figs.

  7. Integrated X-ray testing of the electro-optical breadboard model for the XMM reflection grating spectrometer

    SciTech Connect

    Bixler, J.V.; Craig, W.; Decker, T.; Aarts, H.; Boggende, T. den; Brinkman, A.C.; Burkert, W.; Brauninger, H.; Branduardi-Raymont, G.; Dubbeldam, L.

    1994-07-12

    X-ray calibration of the Electro-Optical Breadboard Model (EOBB) of the XXM Reflection Grating Spectrometer has been carried out at the Panter test facility in Germany. The EOBB prototype optics consisted of a four-shell grazing incidence mirror module followed by an array of eight reflection gratings. The dispersed x-rays were detected by an array of three CCDs. Line profile and efficiency measurements where made at several energies, orders, and geometric configurations for individual gratings and for the grating array as a whole. The x-ray measurements verified that the grating mounting method would meet the stringent tolerances necessary for the flight instrument. Post EOBB metrology of the individual gratings and their mountings confirmed the precision of the grating boxes fabrication. Examination of the individual grating surface`s at micron resolution revealed the cause of anomalously wide line profiles to be scattering due to the crazing of the replica`s surface.

  8. Dispersive element based on grating and tunable Fabry-Perot filter in miniature spectrometer.

    PubMed

    Shi, Zhendong; Fang, Liang; Zhou, Chongxi

    2014-01-01

    We present a new design for the integration of a tunable Fabry-Perot (FP) filter and the grating etched on top of the cavity (IGFP) in the miniature spectrometer. It is based on the predispersion of the grating with the capacity of spatial separation of the spectral component and filter effect of the tunable FP filter. The free spectral range (FSR) of the IGFP is determined by the FSR of the grating, and its resolution depends on the filtering capacity of the FP filter. In the experiment, the high-resolution and wavelength scanning process of the IGFP were demonstrated with a narrowband and broadband light source, respectively. The results of the sub-nanometer resolution agree well with those from a commercial optical spectrum analyzer. Further, the IGFP provides an effective approach to solve the problem of the decrease of spectral resolution in the miniaturization process. PMID:24513992

  9. Arcus: A Low Cost and High Capability X-ray Grating Spectrometer on the ISS

    NASA Astrophysics Data System (ADS)

    Smith, Randall K.

    2014-08-01

    We present the scientific motivation for Arcus, a proposed X-ray grating spectrometer SMEX mission to be deployed on the International Space Station. The primary goals of this mission are to understand structure formation via the imprint it leaves on hot gas in and around galaxies and clusters, to characterize feedback from supermassive black holes by observing highly ionized material coming from these sources, and to study the stellar life cycle from formation through death. The mission parameters are similar to those of the IXO X-ray Grating Spectrometer, with of R>2500 and > 600 sq. cm around the crucial O VII and O VIII lines, and a bandpass from 8-52 A (0.25-1.5 keV).

  10. Calibration of a high resolution grating soft x-ray spectrometer.

    PubMed

    Magee, E W; Dunn, J; Brown, G V; Cone, K V; Park, J; Porter, F S; Kilbourne, C A; Kelley, R L; Beiersdorfer, P

    2010-10-01

    The calibration of the soft x-ray spectral response of a large radius of curvature, high resolution grating spectrometer (HRGS) with a back-illuminated charge-coupled device detector is reported. The instrument is cross-calibrated for the 10-50 Å waveband at the Lawrence Livermore National Laboratory electron beam ion trap (EBIT) x-ray source with the EBIT calorimeter spectrometer. The HRGS instrument is designed for laser-produced plasma experiments and is important for making high dynamic range measurements of line intensities, line shapes, and x-ray sources. PMID:21034013

  11. Resolution improvement of grating spectrometer by using a tunable Fabry-Perot filter

    NASA Astrophysics Data System (ADS)

    Fang, Liang; Shi, Zhendong; Qiu, Chuankai; Zhou, Chongxi

    2015-10-01

    Aiming at the problem of the resolution reduction in a miniaturized grating spectrometer, we presented a method to improve its spectral resolution by inserting a tunable Fabry-Perot filter into its optical path before the grating. The Fabry-Perot filter was designed to filter out a partial spectrogram and separate the original undistinguishable spectral lines so as to make their actual wavelengths can be detected. The different cavity length of the Fabry-Perot filter is corresponding to the different separated partial spectrogram. Combining all the separated partial spectrograms, an entire spectrogram with improved resolution can be achieved. Experimentally, the spectral resolution of a grating dispersive system was improved from 2 nm to 1.2nm in a broad spectral range by insetting a homemade tunable Fabry-Perot filter, which demonstrated the feasibility of this scheme. The tunable Fabry-Perot filter is fit for miniaturization by using MEMS technology and is able to work as an independent module. The method proposed provides a potential way to improve the spectral resolution without reducing the spectral range of the existing miniaturized grating spectrometers.

  12. A near-infrared spectrometer based on novel grating light modulators.

    PubMed

    Wei, Wei; Huang, Shanglian; Wang, Ning; Jin, Zhu; Zhang, Jie; Chen, Weimin

    2009-01-01

    A near-infrared spectrometer based on novel MOEMS grating light modulators is proposed. The spectrum detection method that combines a grating light modulator array with a single near-infrared detector has been applied. Firstly, optics theory has been used to analyze the essential principles of the proposed spectroscopic sensor. Secondly, the grating light modulators have been designed and fabricated by micro-machining technology. Finally, the principles of this spectroscopic sensor have been validated and its key parameters have been tested by experiments. The result shows that the spectral resolution is better than 10 nm, the wavelength deviation is less than 1 nm, the deviation of the intensity of peak wavelength is no more than 0.5%, the driving voltage of grating light modulators array device is below 25 V and the response frequency of it is about 5 kHz. With low cost, satisfactory precision, portability and other advantages, the spectrometer should find potential applications in food safety and quality monitoring, pharmaceutical identification and agriculture product quality classification. PMID:22574065

  13. Space-Resolved Spectrum Diagnose by Soft X-Ray Transmission Grating Spectrometer

    NASA Astrophysics Data System (ADS)

    Shang, Wanli; Zhao, Yang; Xiong, Gang; Yang, Jiamin; Zhu, Tuo

    2011-02-01

    A space-resolving transmission grating spectrometer is established on the Shenguang-III" prototype laser facility and an iterative procedure for unfolding the X-ray spectrum with spatial resolution is described. The diagnostics is applied to measure the X-ray spectrum from laser-entered gold target and the typical space-resolved spectrum is provided. The relative standard uncertainty of the X-ray spectrum from the laser-generated plasma is also determined.

  14. Influence of wavefront aberration on the imaging performance of the solar grating spectrometer.

    PubMed

    Zheng, L H; Rao, C H; Gu, N T; Huang, L H; Qiu, Q

    2016-01-11

    The solar grating spectrometer is an important tool to study the thermodynamic properties of the solar atmosphere with different height distribution, but its imaging performance will be degraded by the wavefront aberration. On the other hand, narrow slit of the grating spectrometer will filter the wavefront aberration to a certain extent. In this paper, the mathematical relation between the wavefront aberration and the imaging performance of the grating spectrometer is derived. The numerical simulation is performed and is validated by the experiment. The results demonstrate that: The influence of the wavefront aberration with the different types and magnitudes on the spectral resolution and the energy utilization is different. The influence of the different slits on the wavefront aberrations is different. Generally, the smaller the slit is, the better the spectral resolution is. However, this is not true for the low-frequency dominated aberration, e.g. the defocus, since its low frequency will also be blocked by the narrow slit. If the influence of the filter slit on the wavefront aberration cannot be taken into account, it will lead to adaptive optics over-compensation. PMID:26832247

  15. Arcus: an ISS-attached high-resolution x-ray grating spectrometer

    NASA Astrophysics Data System (ADS)

    Smith, R. K.; Ackermann, M.; Allured, R.; Bautz, M. W.; Bregman, J.; Bookbinder, J.; Burrows, D.; Brenneman, L.; Brickhouse, N.; Cheimets, P.; Carrier, A.; Freeman, M.; Kaastra, J.; McEntaffer, R.; Miller, J.; Ptak, A.; Petre, R.; Vacanti, G.

    2014-07-01

    We present the design and scientific motivation for Arcus, an X-ray grating spectrometer mission to be deployed on the International Space Station. This mission will observe structure formation at and beyond the edges of clusters and galaxies, feedback from supermassive black holes, the structure of the interstellar medium and the formation and evolution of stars. The mission requirements will be R>2500 and >600 cm2 of effective area at the crucial O VII and O VIII lines, values similar to the goals of the IXO X-ray Grating Spectrometer. The full bandpass will range from 8-52 (0.25-1.5 keV), with an overall minimum resolution of 1300 and effective area >150 cm2. We will use the silicon pore optics developed at cosine Research and proposed for ESA's Athena mission, paired with off-plane gratings being developed at the University of Iowa and combined with MIT/Lincoln Labs CCDs. This mission achieves key science goals of the New Worlds, New Horizons Decadal survey while making effective use of the International Space Station (ISS).

  16. High-Resolution X-ray Spectroscopy with a Grating Spectrometer Explorer on the ISS

    NASA Astrophysics Data System (ADS)

    Smith, Randall

    We present the design and scientific motivation for a X-ray grating spectrometer mission to be deployed on the International Space Station. This mission would observe the Warm-Hot Intergalactic Medium, feedback from supermassive black holes, and the structure of the interstellar medium and halo of the Milky Way, amongst other goals. The mission requirements are similar to those of the IXO X-ray Grating Spectrometer of R=3000 and 1000 cm(2) \\ of effective area at 0.5 keV, with a full bandpass covering at least between 0.3-1 keV. Our initial design baselines the silicon pore optics proposed for ESA's Athena mission with a 4.3 m focal length, paired with off-plane gratings being developed at the University of Iowa combined with MIT/Lincoln Labs CCDs. This mission would achieve core science described in the 2010 New Worlds, New Horizons Decadal survey performed by the US National Research Council while effectively using the ISS and at low cost and low risk.

  17. High resolution TE&TM near infrared compact spectrometer based on waveguide grating structures

    NASA Astrophysics Data System (ADS)

    Martin, G.; Thomas, F.; Heidmann, S.; de Mengin, M.; Courjal, N.; Ulliac, G.; Morand, A.; Benech, P.; Kern, P.; Le Coarer, E...

    2015-05-01

    Integrated optics spectrometers can be essentially classified into two main families: based on Fourier transform or dispersed modes. In the first case, an interferogram generated inside an optical waveguide is sampled using nanodetectors, these scatter light into the detector that is in contact with the waveguide. A dedicated FFT processing is needed in order to recover the spectrum with high resolution but limited spectral range. Another way is to extract the optical signal confined in a waveguide using a surface grating and directly obtain the spectrum by means of a relay optics that generates the spectrum on the Fourier plane of the lens, where the detector is placed. Following this second approach, we present a high-resolution compact dispersive spectrometer (δλ =1.5nm at λ=1050nm) based on guided optics technology. The propagating signal is dispersed out of a waveguide thanks to a surface grating that lays along it. Focused Ion Beam technique is used to etch nano-grooves that act as individual scattering centers and constitute the surface grating along the waveguide. The waveguide is realized using X-cut, Ypropagating Lithium Niobate substrate, where the effective index for TE and TM guided modes is different. This results in a strong angular separation of TE and TM diffracted modes, allowing simultaneous detection of spectra for both polarizations. A simple relay optics, with limited optical aberrations, reimages the diffracted signal on the focal plane array, leading to a robust, easy to align instrument.

  18. High-contrast saturated absorption spectrometer with a grating reflector as an optical frequency locker.

    PubMed

    Kim, J B; Kim, H A; Moon, H S; Lee, H S

    1997-04-20

    By optical feedback of signals obtained with a high-contrast saturated absorption spectrometer as a reference frequency selector, diode laser frequency has been locked to the hyperfine transition line of a Cs atom. We used a grating instead of a mirror for optical feedback to avoid feedback of unwanted modes, because such modes cause mode hopping or generate another frequency component, whose intensity does not decrease even after it passes through an atomic cell twice. Long-term frequency stability has been improved by compensating the cavity length for phase fluctuations. PMID:18253227

  19. Simulation of path delay multiplexing-based Fourier transform spectrometer for fiber Bragg grating interrogation.

    PubMed

    Chelliah, Pandian; Sahoo, Trilochan; Singh, Sheela; Sujatha, Annie

    2015-10-20

    A Fourier transform spectrometer (FTS) used for interrogating a fiber Bragg grating (FBG) consists of a scanning-type interferometer. The FTS has a broad wavelength range of operation and good multiplexing capability. However, it has poor wavelength resolution and interrogation speed. We propose a modification to the FTS using path delay multiplexing to improve the same. Using this method, spatial resolution and interrogation time can be improved by n times by using n path delays. In this paper, simulation results for n=2, 5 are shown. PMID:26560372

  20. Calibration of a helium-cooled infrared spatial radiometer and grating spectrometer

    NASA Technical Reports Server (NTRS)

    Jacobsen, Larry; Sargent, Steve; Wyatt, Clair L.; Steed, Allan J.

    1992-01-01

    Methods used by the Space Dynamics Laboratory of Utah State University (SDL/USU) to calibrate infrared sensors are described, using the Infrared Background Signature Survey (IBSS) spatial radiometer and grating spectrometer as examples. A calibration equation and a radiometric model are given for each sensor to describe their responsivity in terms of individual radiometric parameters. The calibration equation terms include dark offset, linearity, absolute responsivity, and measurement uncertainty, and the radiometric model domains include spatial, spectral, and temporal domains. A portable calibration facility, designed and fabricated by SDL/USU, provided collimated, extended, diffuse scatter, and Jones sources in a single cryogenic dewar. This multi-function calibrator allowed calibration personnel to complete a full calibration of the IBSS infrared radiometer and spectrometer in two 15-day periods. A calibration data system was developed to control and monitor the calibration facility, and to record and analyze sensor data.

  1. Calibration of a Flat Field Soft X-ray Grating Spectrometer for Laser Produced Plasmas

    SciTech Connect

    Park, J; Brown, G V; Schneider, M B; Baldis, H A; Beiersdorfer, P; Cone, K V; Kelley, R L; Kilbourne, C A; Magee, E; May, M J; Porter, F S

    2010-05-12

    We have calibrated the x ray response of a variable line spaced grating spectrometer, known as the VSG, at the Fusion and Astrophysics Data and Diagnostic Calibration Facility at the Lawrence Livermore National Laboratory (LLNL). The VSG has been developed to diagnose laser produced plasmas, such as those created at the Jupiter Laser Facility and the National Ignition Facility at LLNL, and at both the Omega and Omega EP lasers at University of Rochester's Laboratory for Laser Energetics. The bandwidth of the VSG spans the range from {approx} 6 to 60 {angstrom}. The calibration results present here include the VSG's dispersion and quantum efficiency. The dispersion is determined by measuring the x rays emitted from hydrogen-like and helium-like ions of carbon, nitrogen, oxygen, neon, and aluminum. The quantum efficiency is calibrated to an accuracy of 30% or better by normalizing the x ray intensities recorded by the VSG to those simultaneously recorded by an x ray microcalorimeter spectrometer.

  2. The transmission volume-phase holographic grating recorded on dichromated gelatin film used in Raman spectrometer

    NASA Astrophysics Data System (ADS)

    Mei, Qijing; Liu, Peng; Tang, Minxue

    2015-11-01

    With the intrinsic advantages of high diffraction efficiency, signal to noise ratio, wavelength and angular selectivity, and low scattering and absorption, volume phase holographic grating (VPHG) has been widely used for spectroscopy, telecommunications, astronomy and ultra-fast laser sciences. The transmission VPHG combined with on-axis imaging lenses can be used in the Raman spectroscopic imaging, which enables a spectrometer to work at high resolution over a wide field of view, and compresses the configuration to achieve very little vignetting. The subject of this paper is to design a kind of transmission VPHG used in Raman Spectrometer with high diffraction efficiency theoretically. According to the Bragg condition and the coupled wave theory, the diffraction efficiency of transmission VPHG recorded on dichromated gelatin (DCG) has been optimized by using G-solver software, which is applicable to the visible waveband ranging from 0.46μm to 0.70μm. The effects of the recording and reconstruction setup parameters, the amplitude of the index modulation (Δn) and the thickness of the gelatin layer (d), and the polarization state of reconstruction beams on the diffraction efficiency properties of the gratings are analyzed at the same time.

  3. EGRAM- ECHELLE SPECTROGRAPH DESIGN AID

    NASA Technical Reports Server (NTRS)

    Dantzler, A. A.

    1994-01-01

    EGRAM aids in the design of spectrographic systems that utilize an echelle-first order cross disperser combination. This optical combination causes a two dimensional echellogram to fall on a detector. EGRAM describes the echellogram with enough detail to allow the user to effectively judge the feasibility of the spectrograph's design. By iteratively altering system parameters, the desired echellogram can be achieved without making a physical model. EGRAM calculates system parameters which are accurate to the first order and compare favorably to results from ray tracing techniques. The spectrographic system modelled by EGRAM consists of an entrance aperture, collimator, echelle, cross dispersion grating, focusing options, and a detector. The system is assumed to be free of aberrations and the echelle, cross disperser, and detector should be planar. The EGRAM program is menu driven and has a HELP facility. The user is prompted for information such as minimum and maximum wavelengths, slit dimensions, ruling frequencies, detector geometry, and angle of incidence. EGRAM calculates the resolving power and range of order numbers covered by the echellogram. A numerical map is also produced. This tabulates the order number, slit bandpass, and high/middle/low wavelengths. EGRAM can also compute the centroid coordinates of a specific wavelength and order (or vice versa). EGRAM is written for interactive execution and is written in Microsoft BASIC A. It has been implemented on an IBM PC series computer operating under DOS. EGRAM was developed in 1985.

  4. Cost-effective optical coherence tomography spectrometer based on a tilted fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Remund, Stefan; Bossen, Anke; Chen, Xianfeng; Wang, Ling; Adebayo, Adedotun; Zhang, Lin; Považay, Boris; Meier, Christoph

    2014-02-01

    A compact, fiber-based spectrometer for biomedical application utilizing a tilted fiber Bragg grating (TFBG) as integrated dispersive element is demonstrated. Based on a 45° UV-written PS750 TFBG a refractive spectrometer with 2.06 radiant/μm dispersion and a numerical aperture of 0.1 was set up and tested as integrated detector for an optical coherence tomography (OCT) system. Featuring a 23 mm long active region at the fiber the spectrum is projected via a cylindrical lens for vertical beam collimation and focused by an achromatic doublet onto the detector array. Covering 740 nm to 860 nm the spectrometer was optically connected to a broadband white light interferometer and a wide field scan head and electronically to an acquisition and control computer. Tomograms of ophthalmic and dermal samples obtained by the frequency domain OCT-system were obtained achieving 2.84 μm axial and 7.6 μm lateral resolution.

  5. Low-energy inverse photoemission spectroscopy using a high-resolution grating spectrometer in the near ultraviolet range

    SciTech Connect

    Yoshida, Hiroyuki

    2013-10-15

    An inverse photoemission spectroscopy (IPES) apparatus using a Czerny-Turner grating spectrometer is demonstrated. Previous IPES instruments based on grating spectrometers used a concave grating and operated in the vacuum ultraviolet range. The reflectance of such gratings is lower than 20% and the aberration cannot be finely corrected leading to an energy resolution of up to 0.1 eV. In the present study, employing the low energy IPES regime [H. Yoshida, Chem. Phys. Lett. 539540, 180 (2012)], incident electrons with a kinetic energy below 5 eV are used, while photon emission in the range of between 250 and 370 nm is analyzed with a 10-cm Czerny-Turner grating spectrometer. The signal intensity is at least 30 times higher than the previous apparatus. The resolution of photon detection is set at 0.07 eV though the ultimate resolution is one order of magnitude higher. The experiment is performed both by sweeping the electron energy (isochromat mode) and by simultaneously analyzing the photon of whole wavelength range (tunable photon energy mode)

  6. Reflection Grating Array Associated with the Reflection Grating Spectrometer Developed by the Space Research Organization of the Netherlands for the X-ray Multi-Mirror Mission (XMM)

    NASA Technical Reports Server (NTRS)

    Kahn, Steven M.

    2001-01-01

    The University of California, Berkeley (UCB) served as the Principal Investigator institution for the United States participation in the development of the Reflection Grating Spectrometer (RGS) which included the design, development, fabrication, and testing of the Reflection Grating Assembly (RGA). UCB was assisted in this role by the Lawrence Livermore National Laboratory and Columbia University who provided the primary facilities, materials, services and personnel necessary to complete the development. UC Berkeley's Dr. Steven Kahn provided the technical and scientific oversight for the design. development and testing of the RGA units by monitoring the performance of the units at various stages in their development. Dr. Kahn was also the primary contact with the Space Research Organization of the Netherlands (SRON) and represented the RGA development at all SRON and European Space Agency (ESA) reviews of the RGA status. In accordance with the contract, the team designed and developed novel optical technology to meet the unique requirements of the RGS. The ESA XMM-Newton Mission carries two identical Reflection Grating Spectrometers (RGS) behind two of its three nested sets of Wolter I type mirrors. The instrument allows high-resolution measurements in the soft X-ray range (6 to 38 angstroms or 2.1 to 0.3 keV) with a maximum effective area of about 140 sq cm at 15 angstroms. Its design is optimized for the detection of the K-shell transitions of carbon, nitrogen, oxygen, neon, magnesium, and silicon. as well as the L shell transitions of iron. The RGA itself consists of two units. A structure for each unit was designed to hold up to 220 gratings. In its final configuration, one unit holds 182 gratings and the second hold 181 gratings.

  7. [A technology of real-time image compression for convex grating imaging spectrometer].

    PubMed

    Liu, Yang-chuan; Bayanheshig; Cui, Ji-cheng; Tang, Yu-guo

    2012-04-01

    The huge amount of convex grating imaging spectrometer image data brings much pressure to data transmission and storage, so the image must be compressed in real time. Firstly, the image characteristics were analyzed according to the imaging principle, and the compression approach to removing spatial correlation and spectral correlation was achieved; Secondly, the compression algorithms were analyzed and the 3-D compression scheme of one-order linear compression in spectral dimension and JPEG2000 compression in spatial dimension was proposed. Finally, a real-time compression system based on FPGA and ADV212 was designed, in which FPGA was used for logic control and implementation of prediction algorithm, and ADV212 was used for JPEG2000 compression. The analysis result shows that the system has the ability of lossless and lossy compression, enabling real-time image compression. PMID:22715801

  8. A soft x-ray transmission grating imaging-spectrometer for the National Ignition Facility

    SciTech Connect

    Moore, A S; Guymer, T M; Kline, J L; Morton, J; Taccetti, M; Lanier, N E; Bentley, C; Workman, J; Peterson, B; Mussack, K; Cowan, J; Prasad, R; Richardson, M; Burns, S; Kalantar, D H; Benedetti, L R; Bell, P; Bradley, D; Hsing, W; Stevenson, M

    2012-05-01

    A soft x-ray transmission grating spectrometer has been designed for use on high energy-density physics experiments at the National Ignition Facility (NIF); coupled to one of the NIF gated x-ray detectors (GXD) it records sixteen time-gated spectra between 250 and 1000eV with 100ps temporal resolution. The trade-off between spectral and spatial resolution leads to an optimized design for measurement of emission around the peak of a 100-300eV blackbody spectrum. Performance qualification results from the NIF, the Trident Laser Facility and VUV beamline at the National Synchrotron Light Source (NSLS), evidence a <100{micro}m spatial resolution in combination with a source-size limited spectral resolution that is <10eV at photon energies of 300eV.

  9. A soft x-ray transmission grating imaging-spectrometer for the National Ignition Facility

    SciTech Connect

    Moore, A. S.; Guymer, T. M.; Morton, J.; Bentley, C.; Stevenson, M.; Kline, J. L.; Taccetti, M.; Lanier, N. E.; Workman, J.; Peterson, B.; Mussack, K.; Cowan, J.; Prasad, R.; Richardson, M.; Burns, S.; Kalantar, D. H.; Benedetti, L. R.; Bell, P.; Bradley, D.; Hsing, W.

    2012-10-15

    A soft x-ray transmission grating spectrometer has been designed for use on high energy-density physics experiments at the National Ignition Facility (NIF); coupled to one of the NIF gated x-ray detectors it records 16 time-gated spectra between 250 and 1000 eV with 100 ps temporal resolution. The trade-off between spectral and spatial resolution leads to an optimized design for measurement of emission around the peak of a 100-300 eV blackbody spectrum. Performance qualification results from the NIF, the Trident Laser Facility and vacuum ultraviolet beamline at the National Synchrotron Light Source, evidence a <100 {mu}m spatial resolution in combination with a source-size limited spectral resolution that is <10 eV at photon energies of 300 eV.

  10. Alignment based on a no adjustment philosophy for the Immersion Grating Infrared Spectrometer (IGRINS)

    NASA Astrophysics Data System (ADS)

    Han, Jeong-Yeol; Yuk, In-Soo; Ko, Kyeongyeon; Oh, Heeyoung; Nah, Jakyoung; Oh, Jae Sok; Park, Chan; Lee, Sungho; Kim, Kang-Min; Chun, Moo-Young; Jaffe, Daniel T.; Pak, Soojong; Gully-Santiago, Michael

    2012-12-01

    IGRINS, the Immersion GRating INfrared Spectrometer includes an immersion grating made of silicon and observes both H-band (1.49~1.80 ?m) and K-band (1.96~2.46 ?m), simultaneously. In order to align such an infrared optical system, the compensator in its optical components has been adjusted within tolerances at room temperature without vacuum environment. However, such a system will ultimately operate at low temperature and vacuum with no adjustment mechanism. Therefore a reasonable relationship between different environmental variations such as room and low temperature might provide useful knowledge to align the system properly. We are attempting to develop a new process to predict the Wave Front Error (WFE), and to produce correct mechanical control values when the optical system is perturbed by moving the lens at room temperature. The purpose is to provide adequate optical performance without making changes at operating temperature. In other words, WFE was measured at operating temperature without any modification but a compensator was altered correctly at room temperature to meet target performance. The `no adjustment' philosophy was achieved by deterministic mechanical adjustment at room temperature from a simulation that we developed. In this study, an achromatic doublet lens was used to substitute for the H and K band camera of IGRINS. This novel process exhibits accuracy predictability of about 0.002 ? rms WFE and can be applied to a cooled infrared optical systems.

  11. AEGIS: An Astrophysics Experiment for Grating and Imaging Spectroscopy---a Soft X-ray, High-resolution Spectrometer

    NASA Astrophysics Data System (ADS)

    Huenemoerder, David; Bautz, M. W.; Davis, J. E.; Heilmann, R. K.; Houck, J. C.; Marshall, H. L.; Neilsen, J.; Nicastro, F.; Nowak, M. A.; Schattenburg, M. L.; Schulz, N. S.; Smith, R. K.; Wolk, S.; AEGIS Team

    2012-01-01

    AEGIS is a concept for a high-resolution soft X-ray spectroscopic observatory developed in response to NASA's request for definitions of the next X-ray astronomy mission. At a small fraction of the cost of the once-planned International X-ray Observatory (IXO), AEGIS has capabilities that surpass IXO grating spectrometer requirements, and which are far superior to those of existing soft X-ray spectrometers. AEGIS incorporates innovative technology in X-ray optics, diffraction gratings and detectors. The mirror uses high area-to-mass ratio segmented glass architecture developed for IXO, but with smaller aperture and larger graze angles optimized for high-throughput grating spectroscopy with low mass and cost. The unique Critical Angle Transmission gratings combine low mass and relaxed figure and alignment tolerances of Chandra transmission gratings but with high diffraction efficiency and resolving power of blazed reflection gratings. With more than an order of magnitude better performance over Chandra and XMM grating spectrometers, AEGIS can obtain high quality spectra of bright AGN in a few hours rather than 10 days. Such high resolving power allows detailed kinematic studies of galactic outflows, hot gas in galactic haloes, and stellar accretion flows. Absorption line spectroscopy will be used to study large scale structure, cosmic feedback, and growth of black holes in thousands of sources to great distances. AEGIS will enable powerful multi-wavelength investigations, for example with Hubble/COS in the UV to characterize the intergalactic medium. AEGIS will be the first observatory with sufficient resolution below 1 keV to resolve thermally-broadened lines in hot ( 10 MK) plasmas. Here we describe key science investigations enable by Aegis, its scientific payload and mission plan. Acknowledgements: Support was provided in part by: NASA SAO contract SV3-73016 to MIT for the Chandra X-ray Center and Science Instruments; NASA grant NNX08AI62G; and the MKI Instrumentation Development Fund.

  12. Reflection grating spectrometer onboard the ESA x-ray multi-mirror (XMM) mission

    NASA Astrophysics Data System (ADS)

    den Herder, Jan-Willem; Aarts, Henry J.; van den Berg, Marcel L.; Bixler, Jay V.; den Boggende, Antonius J.; Branduardi-Raymont, G.; Brinkman, Albert C.; Decker, Todd A.; Dubbeldam, Luc; Hailey, Charles J.; Jansen, Fred A.; Kahn, Steven M.; de Korte, Piet A.; Mauche, C. W.; Montesanti, Richard C.; Paerels, Frits B.; Spruijt, Hugo; Thomsen, K.; Verhoeve, P.; Zehnder, A.

    1994-09-01

    The Reflection Grating Spectrometer (RGS) onboard the ESA satellite XMM (X-ray Multi Mirror mission) combines a high resolving power (approximately 400 at 0.5 keV) with a large effective area (approximately 200 cm(superscript 2)). The spectral range selected for RGS (5 - 35 angstroms) contains the K shell transitions of N, O, Ne, Mg, Al, Si and S as well as the important L shell transitions of FE. The resolving power allows the study of a wide variety of challenging scientific questions. Detailed temperature diagnostics are feasible as the ionization balance is a unique function of the distribution of the electron temperature. Density diagnostics are provided by studying He-like triplets where the ratio of the forbidden to intercombination lines varies with density. Other fields of interest include the determination of elemental abundances, the study of optical depth effects, velocity diagnostics by measuring Doppler shifts and the estimate of magnetic fields through the observation of Zeeman splitting. The resolving power is obtained by an array of 240 gratings placed behind the mirrors of the telescope, dispersing about half of the X-rays in two spectroscopic orders. The X-rays are recorded by an array of 9 large format CCDs. These CCDs are operated in the frame transfer mode. They are back illuminated as the quantum efficiency of front illuminated devices is poor at low energies because of their poly-silicon gate structure. To suppress dark current the CCDs are passively cooled. In order to obtain the effective area of about 200 cm(superscript 2), grating arrays and CCD cameras are placed behind two of the three XMM telescopes. A model of RGS was tested last autumn ('93) at the Panter long beam X-ray facility in Munich. The model consisted of a subset of four mirrors, eight representative gratings covering a small section of the inner mirror shells and a CCD camera containing three CCDs. The purpose of these tests was to verify the resolution and sensitivity of the instrument as a function of X-ray energy. Extensive simulations, using a Monte Carlo raytracing code, are used to interpret these tests. Preliminary results of these tests will be discussed and compared to the calculated response.

  13. Fifteen years of experience with the Reflection Grating Spectrometer on XMM-Newton

    NASA Astrophysics Data System (ADS)

    de Vries, C. P.; den Herder, J. W.; Gonzalez-Riestra, R.; Gabriel, C.; Kaastra, J. S.; Raassen, A. J. J.; Paerels, F. B. S.; Pollock, A. M. T.; Ibarra, I.

    2014-07-01

    The RGS instrument is the X-ray spectrometer on board the XMM-Newton satellite, launched December 1999, and still fully operational. It consists of a reflection grating to disperse the incoming X-rays and a CCD camera as detector. In the past fifteen years a lot of experience has been gained in operating and calibrating this instrument. In this presentation we report on the calibration methods and status, new instrumental modes and detector performance, which were acquired and developed based on the in-flight experiences with the instrument. Selecting the proper operating modes, combined with careful data processing based on target characteristics and science goals, allows detection of weak spectral features, despite slowly degrading detectors due to radiation damage and contamination. At present the instrument has excellent health status and performance, and will be one of the few major instruments for X-ray spectroscopy in the coming years, until supplemented by new missions like ASTRO-H and, in particular, Athena.

  14. Design, simulation and test of silicon immersed gratings: key to compact spectrometers in the short-wave infrared

    NASA Astrophysics Data System (ADS)

    van Amerongen, Aaldert H.; Tol, Paul J. J.; Coppens, Tonny H. M.; Schuurhof, Ruud; Laubert, Phillip P.; Ruijter, Jos; Hoogeveen, Ruud W. M.

    2014-10-01

    We present results of our integrated approach to the development of novel diffraction gratings. At SRON we manufacture prism-shaped silicon immersed gratings. Diffraction takes place inside the high-refractive index medium, boosting the resolving power and the angular dispersion. This enables highly compact spectrometer designs. We are continuously improving the cycle of design, simulation and test to create custom gratings for space and ground-based spectroscopic applications in the short-wave infrared wavelength range. Applications are space-based monitoring of greenhouse and pollution gases in the Earth atmosphere and ground-based SWIR spectroscopy for, a.o., characterization of exo-planet atmospheres [1]. We make gratings by etching V-shaped grooves in mono-crystalline silicon. The groove facets are aligned with the crystal lattice yielding a smooth and highly deterministic groove shape. This enables us to predict the polarized efficiency performance accurately by simulation. Feeding back manufacturing tolerances from our production process, we can also determine reliable error bars for the predicted performance. Combining the simulated values for polarized efficiency with ray-tracing, we can optimize the shape of the grating prism to eliminate unwanted internal reflections. In this contribution we present the architecture of our design and simulation platform as well as a description of test setups and typical results.

  15. Designing Echelle Spectrographs

    NASA Technical Reports Server (NTRS)

    Dantzler, A.

    1987-01-01

    Performance numbers and output maps computed from inputs supplied by user. Echelle Spectrograph Design Aid program (EGRAM) aids in design of spectrographic systems that utilize echelle/first-order crossdisperser combinations. Optical combination causes two-dimensional echellogram to fall on detector. Describes echellogram with enough detail to enable user to judge effectively feasibility of spectrograph design. By iteratively altering system parameters, desired echellogram achieved without making physical model. Calculates system parameters accurately to first order and compare favorably to results from raytracing techniques. EGRAM written in two versions. FORTRAN 77, and Microsoft BASIC A.

  16. Modeling and simulation of blazed grating based on MEMS scanning micro-mirror for NIR micro-spectrometer

    NASA Astrophysics Data System (ADS)

    Zhou, Ying; Wen, Zhiyu; Yang, Tingyan; Lei, Hongjie

    2015-11-01

    Near infrared micro-spectrometer (NIRMS) as a vital detection equipment for various elements has been investigated over the last few years. Traditional MEMS NIRMS employs CCD array detectors for NIR spectrum collection and this leads to higher fabrication cost. In this paper, to ensure the higher diffraction efficiency as well as lower fabrication cost, a novel blazed grating based on MEMS scanning micro-mirror (SMM) is proposed. By our design method, the NIRMS needs only one single InGaAs detector photo diode to collect NIR spectrum and ensure the high diffraction efficiency. Our results show that the diffraction efficiency of the blazed grating is almost 50% and the peak value reaches to 90% in the range of 900-2,100 nm while the optical scanning angle is 14.2.

  17. A tower concept for the off-plane x-ray grating spectrometer for the International X-ray Observatory

    NASA Astrophysics Data System (ADS)

    Casement, Suzanne; McEntaffer, Randall L.; Cash, Webster; Johnson, Tim; Lillie, Charles; Dailey, Dean

    2010-07-01

    An Off-Plane X-ray Grating Spectrometer (OP-XGS) concept is being developed to meet the needs of the International X-ray Observatory (IXO). The OP-XGS will provide the required spectral resolution of R >3000 over the 0.3 - 1 keV band with >1000 cm2 effective collecting area, using experience gained with the current generation of reflection gratings already flown on rocket experiments. We have developed several potential configurations that meet or exceed these requirements. This paper will focus on the mechanical design and requirements for one of these configurations, the "tower" concept. This configuration mounts the grating modules to the instrument platform via a tower, allowing direct alignment with the camera module. This reduces the complexity of the alignment problem while also minimizing the overall mass of the XGS. We have developed an initial interface concept and resource requirements for this option to be reviewed by the mission teams for design drivers. We contrast the resource requirements for this concept with those required for other concepts which have been reviewed by the OP-XGS team. Further, we have identified those portions of the tower design concept that will require potential technology demonstration to reach TRL 6 prior to the Preliminary Design Review.

  18. A Tower Concept for the Off-Plane X-ray Grating Spectrometer for the International X-ray Observatory

    NASA Astrophysics Data System (ADS)

    Casement, L. Suzanne; McEntaffer, R.; Cash, W.; Johnson, T.; Lillie, C.

    2010-02-01

    An Off-Plane X-ray Grating Spectrometer (OP-XGS) concept is being developed to meet the needs of the International X-ray Observatory (IXO). The OP-XGS will provide the required spectral resolution of R >3000 over the 0.3 - 1 keV band with >1000 cm2 effective collecting area, using experience gained with the current generation of reflection gratings already flown on rocket experiments. We have developed several potential configurations that meet or exceed these requirements and the optical modeling of these designs is presented by Dr. Webster Cash elsewhere at this conference. This paper will focus on the mechanical design and requirements for one of these configurations, the "tower concept. This configuration mounts the grating modules to the instrument platform via a tower, allowing direct alignment with the camera module. This reduces the complexity of the alignment problem while also minimizing the overall mass of the XGS. We have developed an initial interface concept and resource requirements for this option to be reviewed by the mission teams for design drivers. We contrast the resource requirements for this concept with those required for other concepts which have been reviewed by the OP-XGS team. Further, we have identified those portions of the tower design concept that will require potential technology demonstration to reach TRL 6 prior to sensor Preliminary Design Review.

  19. X-ray grating spectrometer for opacity measurements in the 50 eV to 250 eV spectral range at the LULI 2000 laser facility

    SciTech Connect

    Reverdin, Charles; Caillaud, T.; Gilleron, F.; Pain, J. C.; Silvert, V.; Soullie, G.; Villette, B.; Thais, Frederic; Loisel, Guillaume; Blenski, T.; Poirier, M.; Busquet, M.; Bastiani-Ceccotti, S.; Serres, F.; Ducret, J. E.; Foelsner, W.; Gilles, D.; Turck-Chieze, S.

    2012-10-15

    An x-ray grating spectrometer was built in order to measure opacities in the 50 eV to 250 eV spectral range with an average spectral resolution {approx} 50. It has been used at the LULI-2000 laser facility at Ecole Polytechnique (France) to measure the {Delta}n = 0, n = 3 transitions of several elements with neighboring atomic number: Cr, Fe, Ni, and Cu in the same experimental conditions. Hence a spectrometer with a wide spectral range is required. This spectrometer features one line of sight looking through a heated sample at backlighter emission. It is outfitted with one toroidal condensing mirror and several flat mirrors cutting off higher energy photons. The spectral dispersion is obtained with a flatfield grating. Detection consists of a streak camera sensitive to soft x-ray radiation. Some experimental results showing the performance of this spectrometer are presented.

  20. X-ray grating spectrometer for opacity measurements in the 50 eV to 250 eV spectral range at the LULI 2000 laser facility.

    PubMed

    Reverdin, Charles; Thais, Frdric; Loisel, Guillaume; Busquet, M; Bastiani-Ceccotti, S; Blenski, T; Caillaud, T; Ducret, J E; Foelsner, W; Gilles, D; Gilleron, F; Pain, J C; Poirier, M; Serres, F; Silvert, V; Soullie, G; Turck-Chieze, S; Villette, B

    2012-10-01

    An x-ray grating spectrometer was built in order to measure opacities in the 50 eV to 250 eV spectral range with an average spectral resolution ? 50. It has been used at the LULI-2000 laser facility at E?cole Polytechnique (France) to measure the ?n = 0, n = 3 transitions of several elements with neighboring atomic number: Cr, Fe, Ni, and Cu in the same experimental conditions. Hence a spectrometer with a wide spectral range is required. This spectrometer features one line of sight looking through a heated sample at backlighter emission. It is outfitted with one toroidal condensing mirror and several flat mirrors cutting off higher energy photons. The spectral dispersion is obtained with a flatfield grating. Detection consists of a streak camera sensitive to soft x-ray radiation. Some experimental results showing the performance of this spectrometer are presented. PMID:23126955

  1. Discovery of Narrow X-Ray Absorption Lines from NGC 3783 with the Chandra High Energy Transmission Grating Spectrometer.

    PubMed

    Kaspi; Brandt; Netzer; Sambruna; Chartas; Garmire; Nousek

    2000-05-20

    We present the first grating-resolution X-ray spectra of the Seyfert 1 galaxy NGC 3783, obtained with the High Energy Transmission Grating Spectrometer on the Chandra X-Ray Observatory. These spectra reveal many narrow absorption lines from the H-like and He-like ions of O, Ne, Mg, Si, S, and Ar as well as Fe xvii-Fe xxi L-shell lines. We have also identified several weak emission lines, mainly from O and Ne. The absorption lines are blueshifted by a mean velocity of approximately 440+/-200 km s-1 and are not resolved, indicating a velocity dispersion within the absorbing gas of a few hundred kilometers per second or less. We measure the lines' equivalent widths and compare them with the predictions of photoionization models. The best-fitting model has a microturbulence velocity of 150 km s-1 and a hydrogen column density of 1.3x1022 cm-2. The measured blueshifts and inferred velocity dispersions of the X-ray absorption lines are consistent with those of the strongest UV absorption lines observed in this object. However, simple models that propose to strictly unify the X-ray and UV absorbers have difficulty explaining simultaneously the X-ray and UV absorption-line strengths. PMID:10828998

  2. Echelle and etalon used for spectral metrology of excimer laser lithographic light sources at 193nm

    NASA Astrophysics Data System (ADS)

    Gao, Fei; Zhao, Jiangshan; Liu, Guangyi; Wang, Qian; Bai, Lujun

    2015-10-01

    In lithography, online spectral metrology of excimer laser lithographic light sources is used as the evaluation and monitoring the quality of the output laser lithography equipment, through the spectrum measurement we can know the running status of lithography equipment. Center wavelength and Full-Width-At-Half-Maximum(FWHM) are two important indicators of online spectral metrology. Traditional way of accurately measuring laser spectrum is to use a high resolution grating spectrometers. These instruments can provide accurate spectral measurement ,but are very bulky and expensive. Fabry - Perot (FP) etalon is based on the principle of multi-beam interference, high spectral resolution can be done, is a modern high-resolution spectroscopy indispensable instrument. echelle has big blaze Angle, can achieve high The blazed order, realize high resolution(lower than etalon). This paper introduces a method of using Echelle and etalon, through the analysis of the diffraction line fringes of ArF laser and a series of algorithms to deal with data, realize the on-board measurement of center wavelength and FWHM .

  3. [Influence of spectrometer scanning requirements in homemade grating diffuse NIR instrument on NIR veracity].

    PubMed

    Qin, Xi-yun; Li, Jun-hui; Yang, Yu-hong; Cai, Gui-min

    2007-02-01

    The influence of instrument parameters, such as scan internal, length of instrument run, frequency of scan background etc, on NIR veracity was studied with a homemade grating diffuse NIR instrument using Yunnan flue-cured tobacco. Results showed that scan interval, such as 8 nm or 16 nm, had no evident influence on NIR quantitative analysis. To improve scan speed, the scan interval the authors decided to use was 16 nm. NIR model was set up which could revise the influence of the length of instrument run. This instrument can clue on baseline shift to decide the frequency of background scanning, which can deduce NIR analysis error and improve NIR veracity. PMID:17514989

  4. Echelle spectrograph software design aid

    NASA Technical Reports Server (NTRS)

    Dantzler, A. A.

    1985-01-01

    A method for mapping, to first order, the spectrograms that result from echelle spectrographic systems is discussed. An in-depth description of the principles behind the method are given so that software may be generated. Such software is an invaluable echelle spectrograph design aid. Results from two applications are discussed.

  5. Colorado High-resolution Echelle Stellar Spectrograph (CHESS)

    NASA Astrophysics Data System (ADS)

    Beasley, Matthew; Burgh, Eric; France, Kevin

    2010-07-01

    We discuss the design of a new high-efficiency, high-resolution far ultraviolet echelle spectrograph. Our project concentrates on utilizing new technologies for gratings and detectors to reduce the impact of scattered light and maximize quantum efficiency over a large bandpass. This program will enable advances in a vast number of astrophysical subjects. Topics ranging from protoplanetary disks to the intergalactic medium can be addressed by incorporating such a spectrograph into a future, long-duration mission.

  6. Post-SM4 Sensitivity Calibration of the STIS Echelle Modes

    NASA Astrophysics Data System (ADS)

    Bostroem, K. Azalee; Aloisi, A.; Bohlin, R.; Hodge, P.; Proffitt, C.

    2012-01-01

    On-orbit sensitivity curves for all echelle modes were derived for post - servicing mis- sion 4 data using observations of the DA white dwarf G191-B2B. Additionally, new echelle ripple tables and grating dependent bad pixel tables were created for the FUV and NUV MAMA. We review the procedures used to derive the adopted throughputs and implement them in the pipeline as well as the motivation for the modification of the additional reference files and pipeline procedures.

  7. Computed tomography imaging spectrometer (CTIS) with 2D reflective grating for ultraviolet to long-wave infrared detection especially useful for surveying transient events

    NASA Technical Reports Server (NTRS)

    Wilson, Daniel W. (Inventor); Maker, Paul D. (Inventor); Muller, Richard E. (Inventor); Mouroulis, Pantazis Z. (Inventor)

    2003-01-01

    The optical system of this invention is an unique type of imaging spectrometer, i.e. an instrument that can determine the spectra of all points in a two-dimensional scene. The general type of imaging spectrometer under which this invention falls has been termed a computed-tomography imaging spectrometer (CTIS). CTIS's have the ability to perform spectral imaging of scenes containing rapidly moving objects or evolving features, hereafter referred to as transient scenes. This invention, a reflective CTIS with an unique two-dimensional reflective grating, can operate in any wavelength band from the ultraviolet through long-wave infrared. Although this spectrometer is especially useful for rapidly occurring events it is also useful for investigation of some slow moving phenomena as in the life sciences.

  8. Computed Tomography Imaging Spectrometer (CTIS) with 2D Reflective Grating for Ultraviolet to Long-Wave Infrared Detection Especially Useful for Surveying Transient Events

    NASA Technical Reports Server (NTRS)

    Wilson, Daniel W. (Inventor); Maker, Paul D. (Inventor); Muller, Richard E. (Inventor); Mouroulis, Pantazis Z. (Inventor)

    2003-01-01

    The optical system of this invention is an unique type of imaging spectrometer, i.e. an instrument that can determine the spectra of all points in a two-dimensional scene. The general type of imaging spectrometer under which this invention falls has been termed a computed-tomography imaging spectrometer (CTIS). CTIS's have the ability to perform spectral imaging of scenes containing rapidly moving objects or evolving features, hereafter referred to as transient scenes. This invention, a reflective CTIS with an unique two-dimensional reflective grating, can operate in any wavelength band from the ultraviolet through long-wave infrared. Although this spectrometer is especially useful for events it is also for investigation of some slow moving phenomena as in the life sciences.

  9. Correction and analysis of noise in Hadamard transform spectrometer with digital micro-mirror device and double sub-gratings

    NASA Astrophysics Data System (ADS)

    Quan, Xiangqian; Liu, Hua; Lu, Zhenwu; Chen, Xiangzi; Wang, Xiaoduo; Xu, Jialin; Gao, Qun

    2016-01-01

    In order to correct spectra anomaly in Hadamard transform (HT) spectrometer with digital micro-mirror device (DMD) and double sub-gratings (DSG) which was proposed by our research team, the analysis of noise is carried out from two aspects, one noise is the intensity noise caused by the instability of light source, detector, substance concentration, electrical system, etc. The other noise is the spectral response noise caused by the diffraction efficiency of DMD and DSG. Consequently, the effects of these noises on Hadamard transform encoding matrix equation are determined and the decoding matrix equations are derived. As a result, the method of inserting testing masks is proposed to correct the intensity noise and the method of correcting spectra by spectral response function is presented to correct the spectral response noise. The simulation results show that the Pearson correlation coefficient (PCC) between detected spectra and original spectra is enhanced gradually from 0.9108 to 0.9997 and the experimental results also demonstrate those two methods are valid, concise and significant.

  10. High Resolution X-Ray Spectroscopy of zeta Puppis with the XMM-Newton Reflection Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Kahn, S. M.; Leutenegger, M. A.; Cottam, J.; Rauw, G.; Vreux, J.-M.; denBoggende, A. J. F.; Mewe, R.; Guedel, M.

    2000-01-01

    We present the first high resolution X-ray spectrum of the bright O4Ief supergiant star Puppis, obtained with the Reflection Grating Spectrometer on- board XMM-Newton. The spectrum exhibits bright emission lines of hydrogen-like and helium-like ions of nitrogen, oxygen, neon, magnesium, and silicon, as well as neon-like ions of iron. The lines are all significantly resolved, with characteristic velocity widths of order 1000 - 1500 km/ s. The nitrogen lines are especially strong, and indicate that the shocked gas in the wind is mixed with CNO-burned material, as has been previously inferred for the atmosphere of this star from ultraviolet spectra. We find that the forbidden to intercombination line ratios within the helium-like triplets are anomalously low for N VI, O VII, and Ne IX. While this is sometimes indicative of high electron density, we show that in this case, it is instead caused by the intense ultraviolet radiation field of the star. We use this interpretation to derive constraints on the location of the X-ray emitting shocks within the wind that agree remarkably well with current theoretical models for this system.

  11. Efficiency calibration of the first multilayer-coated holographic ion-etched flight grating for a sounding rocket high-resolution spectrometer

    SciTech Connect

    Kowalski, Michael P.; Barbee, Troy W. Jr.; Heidemann, Klaus F.; Gursky, Herbert; Rife, Jack C.; Hunter, William R.; Fritz, Gilbert G.; Cruddace, Raymond G.

    1999-11-01

    We have fabricated the four flight gratings for a sounding rocket high-resolution spectrometer using a holographic ion-etching technique. The gratings are spherical (4000-nm radius of curvature), large (160 mmx90 mm), and have a laminar groove profile of high density (3600 grooves/mm). They have been coated with a high-reflectance multilayer of Mo/Si. Using an atomic force microscope, we examined the surface characteristics of the first grating before and after multilayer coating. The average roughness is approximately 3 Aa rms after coating. Using synchrotron radiation, we completed in efficiency calibration map over the wavelength range 225-245 Aa. At an angle of incidence of 5 degree sign and a wavelength of 232 Aa, the average efficiency in the first inside order is 10.4{+-}0.5%, and the derived groove efficiency is 34.8{+-}1.6%. These values exceed all previously published results for a high-density grating. (c) 1999 Optical Society of America.

  12. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, Antonio J. (Albuquerque, NM); Butler, Michael A. (Albuquerque, NM); Sinclair, Michael B. (Albuquerque, NM); Senturia, Stephen D. (Brookline, MA)

    1998-01-01

    An electrically-programmable diffraction grating. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers).

  13. The opto-mechanical design of the Colorado High-resolution Echelle Stellar Spectrograph (CHESS)

    NASA Astrophysics Data System (ADS)

    Kane, Robert; Beasley, Matthew; Green, James; Burgh, Eric; France, Kevin

    2011-09-01

    We present the Colorado High-resolution Echelle Stellar Spectrograph (CHESS) sounding rocket payload. The design uses a mechanical collimator made from a grid of square tubing, an objective echelle grating, a holographically-ruled cross-disperser, a new 40 mm MCP with a cross strip anode or a delta-doped 3.5k x 3.5k CCD detector. The optics are suspended using carbon fiber rods epoxied to titanium inserts to create a space frame structure. A preliminary design is presented.

  14. Spectroscopic evaluation of three different gratings used for a flat-field extreme ultraviolet spectrometer to monitor Delta n=1 transitions from medium-Z impurities in 10-30 A.

    PubMed

    Chowdhuri, Malay Bikas; Morita, Shigeru; Goto, Motoshi; Sasai, Hiroyuki

    2008-10-01

    Spectral characteristics of varied line spacing 2400 grooves/mm gratings used for a flat-field extreme ultraviolet spectrometer have been evaluated to monitor Delta n=1 (n=2-3) transitions from medium-Z impurities in 10-30 A, where many spectral lines from metallic impurities closely exist. For this purpose emission spectra of the Delta n=1 transitions from partially L-shell-ionized Ti and Fe have been measured in large helical device. At first, a ruled and a holographic grating were utilized for the comparative study. Both gratings suppressed higher order light effectively but spectral sensitivity was much higher for the holographic grating. The ruled grating, however, attained better spectral resolution (0.083 A at 18.97 A) in the 10-100 A range compared to that (0.130 A) of the holographic grating. After that a recently developed new holographic grating with different laminar shapes and line spacings has attempted to improve the spectral resolution. As a result, it has considerably improved the spectral resolution in the 10-30 A range, i.e., approximately 0.090 A. However, it is found that the experimentally obtained spectral resolution is quit poor compared to the computationally simulated one, suggesting a technical difficulty in manufacturing exactly the varied line spacing of the holographic grating at such a short wavelength range. PMID:19044679

  15. Grating spectrometer system for beam emission spectroscopy diagnostics using high-energy negative-ion-based neutral beam injection on LHD.

    PubMed

    Kado, S; Oishi, T; Yoshinuma, M; Ida, K

    2010-10-01

    A beam emission spectroscopy (BES) system was developed for density gradient and fluctuation diagnostics in the Large Helical Device (LHD). In order to cover the large Doppler shift of the H? beam emission because of the high-energy negative-ion-based neutral beam atom (acceleration voltage V(acc)=90-170?kV) and the large motional Stark splitting due to the large vB field (magnetic field B=3.0?T), a grating spectrometer was used instead of a conventional interference filter system. The reciprocal linear dispersion is about 2 nm/mm, which is sufficient to cover the motional Stark effect spectra using an optical fiber with a diameter of 1 mm. PMID:21033913

  16. Fabrication and testing of a silicon immersion grating for infrared spectroscopy

    SciTech Connect

    Kuzmenko, P.J.; Ciarlo, D.R.; Stevens, C.G.

    1994-07-25

    Recent advances in silicon micromachining techniques (e.g. anisotropic etching) allow the fabrication of very coarse infrared echelle gratings. When used in immersion mode, the dispersion is increased proportionally to the refractive index. This permits a very significant reduction in the overall size of a spectrometer while maintaining the same resolution. We have fabricated a right triangular prism (30{times}60{times}67 mm with a rectangular entrance face 30{times}38 mm) from silicon with a grating etched into the face of the hypotenuse. The grating covers an area of 32 mm by 64 mm and has a 97.5 PM periodicity with a blaze angle of 63.4{sup o}. The groove surfaces are very smooth with a roughness of a few manometers. Random defects in the silicon are the dominant source of grating scatter ({approx} 12% at 3.39 {mu}m). We measure a grating ghost intensity of 1.2%. The diffraction peak is quite narrow, slightly larger than the Airy disc diameter at F/12. However due to wavefront aberrations, perhaps 15--20% of the diffracted power is in the peak with the rest distributed in a diameter roughly five times the Airy disc.

  17. The coude spectrograph and echelle scanner of the 2.7 m telescope at McDonald Observatory.

    NASA Technical Reports Server (NTRS)

    Tull, R. G.

    1972-01-01

    Discussion of certain design aspects of the coude spectrograph, and description of the coude scanner that uses some of the spectrograph optics. The configuration of the large echelle grating used is reviewed along with the systems of computer scanner control and data handling.

  18. The Time-Dependent Sensitivity of the MAMA and CCD Long-Slit Gratings

    NASA Astrophysics Data System (ADS)

    Holland, Stephen T.; Aloisi, Alessandra; Bostroem, Azalee; Oliveria, Cristina; Proffitt, Charles

    2014-12-01

    We present the results of observing flux standard stars used to determine trends in the sensitivities of the five STIS low-resolution, long-slit gratings between 1997 and 2013. Also, the assumption that the sensitivity trends for the medium-resolution and echelle gratings are the same as those for the corresponding low-resolution gratings is tested.

  19. Data Pipelines for the TRES Echelle Spectrograph

    NASA Astrophysics Data System (ADS)

    Mink, D. J.

    2011-07-01

    An IRAF-based processing pipeline has been written to reduce spectra from the Smithsonian Astrophysical Observatory's TRES (Tillinghast Reflector Echelle Spectrograph) two-fiber echelle spectrograph on Mt. Hopkins in Arizona. A modular system was written in IRAF so that the same software could be used at the telescope for quick-look processing and later with more accuracy for scientific processing. IRAF tasks developed for the SAO FAST long-slit and Hectospec multi-fiber spectrographs, as well as NOAO-developed echelle tasks, were adapted for this instrument.

  20. Optical grating analyzer studies

    NASA Technical Reports Server (NTRS)

    Mcdonald, J. K.

    1974-01-01

    A spectrometer was specifically designed and developed to observe grating spectra over a range of incidence angles from normal to almost grazing incidence. A unique scanning and focusing mechanism is utilized to keep the exit slit on the Rowland circle. Polarization effects in the vacuum were investigated, and efficiency measurements and spectral scans were made simultaneously with the spectrometer. Results of measurements are given. Applications of the spectrometer to the space program and to the study of contamination on optical surfaces are indicated.

  1. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, A.J.; Butler, M.A.; Sinclair, M.B.; Senturia, S.D.

    1998-05-26

    An electrically-programmable diffraction grating is disclosed. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers). 14 figs.

  2. DYNAMICS OF X-RAY-EMITTING EJECTA IN THE OXYGEN-RICH SUPERNOVA REMNANT PUPPIS A REVEALED BY THE XMM-NEWTON REFLECTION GRATING SPECTROMETER

    SciTech Connect

    Katsuda, Satoru; Tamagawa, Toru; Ohira, Yutaka; Mori, Koji; Tsunemi, Hiroshi; Koyama, Katsuji; Uchida, Hiroyuki

    2013-05-10

    Using the unprecedented spectral resolution of the reflection grating spectrometer (RGS) on board XMM-Newton, we reveal dynamics of X-ray-emitting ejecta in the oxygen-rich supernova remnant Puppis A. The RGS spectrum shows prominent K-shell lines, including O VII He{alpha} forbidden and resonance, O VIII Ly{alpha}, O VIII Ly{beta}, and Ne IX He{alpha} resonance, from an ejecta knot positionally coincident with an optical oxygen-rich filament (the so-called {Omega} filament) in the northeast of the remnant. We find that the line centroids are blueshifted by 1480 {+-} 140 {+-} 60 km s{sup -1} (the first and second term errors are measurement and calibration uncertainties, respectively), which is fully consistent with that of the optical {Omega} filament. Line broadening at 654 eV (corresponding to O VIII Ly{alpha}) is obtained to be {sigma} {approx}< 0.9 eV, indicating an oxygen temperature of {approx}< 30 keV. Analysis of XMM-Newton MOS spectra shows an electron temperature of {approx}0.8 keV and an ionization timescale of {approx}2 Multiplication-Sign 10{sup 10} cm{sup -3} s. We show that the oxygen and electron temperatures as well as the ionization timescale can be reconciled if the ejecta knot was heated by a collisionless shock whose velocity is {approx}600-1200 km s{sup -1} and was subsequently equilibrated due to Coulomb interactions. The RGS spectrum also shows relatively weak K-shell lines of another ejecta feature located near the northeastern edge of the remnant, from which we measure redward Doppler velocities of 650 {+-} 70 {+-} 60 km s{sup -1}.

  3. Dynamics of X-Ray-emitting Ejecta in the Oxygen-rich Supernova Remnant Puppis A Revealed by the XMM-Newton Reflection Grating Spectrometer

    NASA Astrophysics Data System (ADS)

    Katsuda, Satoru; Ohira, Yutaka; Mori, Koji; Tsunemi, Hiroshi; Uchida, Hiroyuki; Koyama, Katsuji; Tamagawa, Toru

    2013-05-01

    Using the unprecedented spectral resolution of the reflection grating spectrometer (RGS) on board XMM-Newton, we reveal dynamics of X-ray-emitting ejecta in the oxygen-rich supernova remnant Puppis A. The RGS spectrum shows prominent K-shell lines, including O VII He? forbidden and resonance, O VIII Ly?, O VIII Ly?, and Ne IX He? resonance, from an ejecta knot positionally coincident with an optical oxygen-rich filament (the so-called ? filament) in the northeast of the remnant. We find that the line centroids are blueshifted by 1480 140 60 km s-1 (the first and second term errors are measurement and calibration uncertainties, respectively), which is fully consistent with that of the optical ? filament. Line broadening at 654 eV (corresponding to O VIII Ly?) is obtained to be ? <~ 0.9 eV, indicating an oxygen temperature of <~ 30 keV. Analysis of XMM-Newton MOS spectra shows an electron temperature of ~0.8 keV and an ionization timescale of ~2 1010 cm-3 s. We show that the oxygen and electron temperatures as well as the ionization timescale can be reconciled if the ejecta knot was heated by a collisionless shock whose velocity is ~600-1200 km s-1 and was subsequently equilibrated due to Coulomb interactions. The RGS spectrum also shows relatively weak K-shell lines of another ejecta feature located near the northeastern edge of the remnant, from which we measure redward Doppler velocities of 650 70 60 km s-1.

  4. Photoelectrochemical fabrication of spectroscopic diffraction gratings, phase 2

    NASA Technical Reports Server (NTRS)

    Rauh, R. David; Carrabba, Michael M.; Li, Jianguo; Cartland, Robert F.; Hachey, John P.; Mathew, Sam

    1990-01-01

    This program was directed toward the production of Echelle diffraction gratings by a light-driven, electrochemical etching technique (photoelectrochemical etching). Etching is carried out in single crystal materials, and the differential rate of etching of the different crystallographic planes used to define the groove profiles. Etching of V-groove profiles was first discovered by us during the first phase of this project, which was initially conceived as a general exploration of photoelectrochemical etching techniques for grating fabrication. This highly controllable V-groove etching process was considered to be of high significance for producing low pitch Echelles, and provided the basis for a more extensive Phase 2 investigation.

  5. Initial Results from the MAVEN IUVS Echelle

    NASA Astrophysics Data System (ADS)

    Clarke, J.

    2015-10-01

    This presentation will give the present status and early results of the echelle channel in the IUVS instrument on the MAVEN spacecraft at Mars. The channel studies H, D, and O in the upper atmosphere of Mars at high spectral resolution (0.008 nm). One primary goal is to study the ratio of D/H in the martian upper atmosphere, and determine the underlying principles that control the escape of H and D into space, with relevance to the historic escape of water from Mars. Initial data indicate that the echelle channel is working well, and we detected the D emission in the first observation of the sunlit disc of Mars.

  6. The assembly, calibration, and preliminary results from the Colorado high-resolution Echelle stellar spectrograph (CHESS)

    NASA Astrophysics Data System (ADS)

    Hoadley, Keri; France, Kevin; Nell, Nicholas; Kane, Robert; Schultz, Ted; Beasley, Matthew; Green, James; Kulow, Jen; Kersgaard, Eliot; Fleming, Brian

    2014-07-01

    The Colorado High-resolution Echelle Stellar Spectrograph (CHESS) is a far ultraviolet (FUV) rocket-borne experiment designed to study the atomic-to-molecular transitions within translucent interstellar clouds. CHESS is an objective echelle spectrograph operating at f/12.4 and resolving power of 120,000 over a band pass of 100 - 160 nm. The echelle flight grating is the product of a research and development project with LightSmyth Inc. and was coated at Goddard Space Flight Center (GSFC) with Al+LiF. It has an empirically-determined groove density of 71.67 grooves/mm. At the Center for Astrophysics and Space Astronomy (CASA) at the University of Colorado (CU), we measured the efficiencies of the peak and adjacent dispersion orders throughout the 90 - 165 nm band pass to characterize the behavior of the grating for pre-flight calibrations and to assess the scattered-light behavior. The crossdispersing grating, developed and ruled by Horiba Jobin-Yvon, is a holographically-ruled, low line density (351 grooves/mm), powered optic with a toroidal surface curvature. The CHESS cross-disperser was also coated at GSFC; Cr+Al+LiF was deposited to enhance far-UV efficiency. Results from final efficiency and reflectivity measurements of both optics are presented. We utilize a cross-strip anode microchannel plate (MCP) detector built by Sensor Sciences to achieve high resolution (25 μm spatial resolution) and data collection rates (~ 106 photons/second) over a large format (40mm round, digitized to 8k x 8k) for the first time in an astronomical sounding rocket flight. The CHESS instrument was successfully launched from White Sands Missile Range on 24 May 2014. We present pre-flight sensitivity, effective area calculations, lab spectra and calibration results, and touch on first results and post-flight calibration plans.

  7. The Spectrometer

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2012-01-01

    In the fall of 1999 I was shown an Ocean Optics spectrometer-in-the-computer at St. Patricks College at Maynooth, Ireland, and thought that I had seen heaven. Of course, it could not resolve the sodium D-lines (I had done that many years before with a homemade wire diffraction grating), and I began to realize that inside was some familiar old…

  8. The Spectrometer

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2012-01-01

    In the fall of 1999 I was shown an Ocean Optics spectrometer-in-the-computer at St. Patricks College at Maynooth, Ireland, and thought that I had seen heaven. Of course, it could not resolve the sodium D-lines (I had done that many years before with a homemade wire diffraction grating), and I began to realize that inside was some familiar old

  9. Electromagnetic diffraction efficiencies for plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Marathay, A. S.; Shrode, T. E.

    1973-01-01

    Results are presented of research activities on holographic grating research. A large portion of this work was performed using rigorous vector diffraction theory, therefore, the necessary theory has been included in this report. The diffraction efficiency studies were continued using programs based on a rigorous theory. The simultaneous occurrence of high diffraction efficiencies and the phenomenon of double Wood's anomalies is demonstrated along with a graphic method for determining the necessary grating parameters. Also, an analytical solution for a grating profile that is perfectly blazed is obtained. The performance of the perfectly blazed grating profile is shown to be significantly better than grating profiles previously studied. Finally, a proposed method is described for the analysis of coarse echelle gratings using rigorous vector diffraction that is currently being developed.

  10. Production and evaluation of silicon immersion gratings for infrared astronomy

    NASA Astrophysics Data System (ADS)

    Marsh, J. P.; Mar, D. J.; Jaffe, D. T.

    2007-06-01

    Immersion gratings, diffraction gratings where the incident radiation strikes the grooves while immersed in a dielectric medium, offer significant compactness and performance advantages over front-surface gratings. These advantages become particularly large for high-resolution spectroscopy in the near-IR. The production and evaluation of immersion gratings produced by fabricating grooves in silicon substrates using photolithographic patterning and anisotropic etching is described. The gratings produced under this program accommodate beams up to 25 mm in diameter (grating areas to 55 mm75 mm). Several devices are complete with appropriate reflective and antireflection coatings. All gratings were tested as front-surface devices as well as immersed gratings. The results of the testing show that the echelles behave according to the predictions of the scalar efficiency model and that tests done on front surfaces are in good agreement with tests done in immersion. The relative efficiencies range from 59% to 75% at 632.8 nm. Tests of fully completed devices in immersion show that the gratings have reached the level where they compete with and, in some cases, exceed the performance of commercially available conventional diffraction gratings (relative efficiencies up to 71%). Several diffraction gratings on silicon substrates up to 75 mm in diameter having been produced, the current state of the silicon grating technology is evaluated.

  11. The GMT-CFA-CARNEGIE-CATOLICA LARGE EARTH FINDER (G-CLEF): A Fiber-fed, Optical Echelle Spectrograph For The Giant Magellan Telescope

    NASA Astrophysics Data System (ADS)

    Szentgyorgyi, Andrew; Furesz, G.; Frebel, A.; Geary, J.; Evans, I.; Norton, T.; Hertz, E.; DePonte Evans, J.; Jordan, A.; Guzman, D.; Epps, H.; Barnes, S.; Crane, J.

    2011-01-01

    The GMT-CfA-Carnegie-Catolica Large Earth Finder (G-CLEF) is a fiber-fed optical echelle spectrograph in concept design study phase for first light at the Giant Magellan Telescope. G-CLEF is designed to be a multipurpose echelle spectrograph that operates in a number of modes so as to enable precision radial velocity (RV) measurements, detailed abundance studies, isotopic abundance measurements and probe the IGM and ISM at high Z. Four resolution modes are implemented with image and pupil slicing. Extremely precise RV will be achieved by vacuum enclosing the spectrograph, with advanced fiber scrambling and state-of-the-art calibrators, especially ultra stabilized etalons and possibly laser frequency combs. The optical design is a asymmetric white pupil design with two camera arms splitting the 350 nm - 950 nm passband into red and blue channels. G-CLEF will have an extremely large, mosaiced echelle grating and volume phase holograph cross dispersers.

  12. First Light Measurements with the XMM-Newton Reflection Grating Spectrometers: Evidence for an Inverse First Ionization Potential Effect and Anomalous Ne Abundance in the Coronae of HR 1099

    NASA Technical Reports Server (NTRS)

    Brinkman, A. C.; Behar, E.; Guedel, M.; Audard, M.; denBoggende, A. J. F.; Branduardi-Raymont, G.; Cottam, J.; Erd, C.; denHerder, J. W.; Jensen, F.

    2000-01-01

    The RS CVn binary system HR 1099 was extensively observed by the XMM-Newton observatory in February 2000 as its first-light target. A total of 570 ks of exposure time was accumulated with the Reflection Grating Spectrometers (RGS). The integrated X-ray spectrum between 5-38A is of unprecedented quality and shows numerous features attributed to transitions of the elements C, N, O, Ne, Mg, Si, S, Fe. Ni, and probably others. We perform an in-depth study of the elemental composition of the average corona of this system, and find that the elemental abundances strongly depend on the first ionisation potential (FIP) of the elements. But different from the solar coronal case, we find an inverse FIP effect, i.e., the abundances (relative to oxygen) increase with increasing FIP. Possible scenarios, e.g., selective enrichment due to Ne-rich flare-like events, are discussed.

  13. Stretchable diffraction gratings for spectrometry

    NASA Astrophysics Data System (ADS)

    Simonov, Aleksey N.; Grabarnik, Semen; Vdovin, Gleb

    2007-07-01

    We have investigated the possibility of using transparent stretchable diffraction gratings for spectrometric applications. The gratings were fabricated by replication of a triangular-groove master into a transparent viscoelastic. The sample length, and hence the spatial period, can be reversibly changed by mechanical stretching. When used in a monochromator with two slits, the stretchable grating permits scanning the spectral components over the output slit, converting the monochromator into a scanning spectrometer. The spectral resolution of such a spectrometer was found to be limited mainly by the wave-front aberrations due to the grating deformation. A model relating the deformation-induced aberrations in different diffraction orders is presented. In the experiments, a 12-mm long viscoelastic grating with a spatial frequency of 600 line pairs/mm provided a full-width at half-maximum resolution of up to ~1.2 nm in the 580-680 nm spectral range when slowly stretched by a micrometer screw and ~3 nm when repeatedly stretched by a voice coil at 15 Hz. Comparison of aberrations in transmitted and diffracted beams measured by a Shack- Hartmann wave-front sensor showed that astigmatisms caused by stretch-dependent wedge deformation are the main factors limiting the resolution of the viscoelastic-grating-based spectrometer.

  14. Stretchable diffraction gratings for spectrometry.

    PubMed

    Simonov, Aleksey N; Grabarnik, Semen; Vdovin, Gleb

    2007-07-23

    We have investigated the possibility of using transparent stretchable diffraction gratings for spectrometric applications. The gratings were fabricated by replication of a triangular-groove master into a transparent viscoelastic. The sample length, and hence the spatial period, can be reversibly changed by mechanical stretching. When used in a monochromator with two slits, the stretchable grating permits scanning the spectral components over the output slit, converting the monochromator into a scanning spectrometer. The spectral resolution of such a spectrometer was found to be limited mainly by the wave-front aberrations due to the grating deformation. A model relating the deformation-induced aberrations in different diffraction orders is presented. In the experiments, a 12-mm long viscoelastic grating with a spatial frequency of 600 line pairs/mm provided a full-width at half-maximum resolution of up to ~1.2 nm in the 580-680 nm spectral range when slowly stretched by a micrometer screw and ~3 nm when repeatedly stretched by a voice coil at 15 Hz. Comparison of aberrations in transmitted and diffracted beams measured by a Shack- Hartmann wave-front sensor showed that astigmatisms caused by stretch-dependent wedge deformation are the main factors limiting the resolution of the viscoelastic-grating-based spectrometer. PMID:19547328

  15. EUV properties of two diffraction gratings

    NASA Technical Reports Server (NTRS)

    Cotton, D.; Chakrabarti, S.; Edelstein, J.; Pranke, J.; Christensen, A. B.

    1988-01-01

    The efficiency and scattering characteristics of a mechanically ruled grating (MRG) and a holographically ruled grating (HRG) are presented. One of these gratings will be employed in the Extreme Ultraviolet Spectrometer, an instrument of the Remote Atmospheric and Ionospheric Detector System to be flown aboard a TIROS satellite in 1991. The HRG showed much less Lyman alpha scattering, while the MRG had the better efficiency over most of the spectral range covered.

  16. WAVELENGTH CALIBRATION OF THE HAMILTON ECHELLE SPECTROGRAPH

    SciTech Connect

    Pakhomov, Yu. V.; Zhao, G.

    2013-10-01

    We present the wavelength calibration of the Hamilton Echelle Spectrograph at Lick Observatory. The main problem with the calibration of this spectrograph arises from the fact that thorium lines are absent in the spectrum of the presumed ThAr hollow-cathode lamp now under operation; numerous unknown strong lines, which have been identified as titanium lines, are present in the spectrum. We estimate the temperature of the lamp's gas which permits us to calculate the intensities of the lines and to select a large number of relevant Ti I and Ti II lines. The resulting titanium line list for the Lick hollow-cathode lamp is presented. The wavelength calibration using this line list was made with an accuracy of about 0.006 Å.

  17. NRES: The Network of Robotic Echelle Spectrographs

    NASA Astrophysics Data System (ADS)

    Siverd, Robert; Eastman, Jason D.; Brown, Timothy M.; Hygelund, John; Henderson, Todd; Tufts, Joseph; Van Eyken, Julian C.; Barnes, Stuart

    2015-01-01

    Las Cumbres Observatory Global Network (LCOGT) is building the Network of Robotic Echelle Spectrographs (NRES), which will consist of six identical, optical (390 - 860 nm) high-precision spectrographs, each fiber-fed simultaneously by two 1 meter telescopes and a thorium argon calibration source, one at each of our observatory sites in the Northern and Southern hemispheres. Thus, NRES will be a single, globally-distributed, autonomous observing facility using twelve 1-m telescopes. Simulations suggest we will achieve long-term radial velocity precision of better than 3 m/s in less than an hour for stars brighter than V = 12. We have been funded with NSF MRI and ATI grants, and expect our first spectrograph to be deployed in mid 2015, with the full network operation of all 6 units beginning in 2016. We will discuss the NRES design, goals, robotic operation, and status, as well as the early results from our prototype spectrograph.

  18. NRES: the network of robotic Echelle spectrographs

    NASA Astrophysics Data System (ADS)

    Eastman, Jason D.; Brown, Timothy M.; Hygelund, John; van Eyken, Julian; Tufts, Joseph R.; Barnes, Stuart

    2014-07-01

    Las Cumbres Observatory Global Network (LCOGT) is building the Network of Robotic Echelle Spectrographs (NRES), which will consist of six identical, optical (390 - 860 nm) high-precision spectrographs, each fiber-fed simultaneously by two 1 meter telescopes and a thorium argon calibration source, one at each of our observatory sites in the Northern and Southern hemispheres. Thus, NRES will be a single, globally-distributed, autonomous observing facility using twelve 1-m telescopes. Simulations suggest we will achieve long-term precision of better than 3 m/s in less than an hour for stars brighter than V = 12. We have been fully funded with an NSF MRI grant, and expect our first spectrograph to be deployed in Spring of 2015, with the full network operation of all 6 units beginning in Spring of 2016. We discuss the NRES design, goals, and robotic operation, as well as the early results from our prototype spectrograph.

  19. Echelle Spectrophotometry of the Orion Nebula

    NASA Astrophysics Data System (ADS)

    Peimbert, M.; Esteban, C.; Torres-Peimbert, S.; Escalante, V.

    1996-12-01

    We present echelle spectroscopy in the 3550 to 7010 A range for two positions of the Orion Nebula. The data were obtained with the 2.1-m telescope at Observatorio Astronomico Nacional in San Pedro Martir, Baja California. We have measured the intensities of several permitted lines of C(+) , N(+) , N(++) , O(0) , O(+) , Ne(0) , Si(+) , Si(++) which are excited by recombination and fluorescence. We have determined the electron temperature, the electron density and the ionic abundances using different intensity ratios. In particular the O(++) /H(+) abundance obtained by recombination lines is 40% higher than that obtained using forbidden [O III] lines. Moreover the C(++) /H(+) value derived from the recombination C II 4267 line is a factor of two higher than that derived in previous work for the same zone using C III] 1906+1909 collisionally excited lines. We estimate that a moderate value of t(2) = 0.025 +/- 0.015 can account for these discrepancies.

  20. Airborne spectrometer senses several gases

    NASA Technical Reports Server (NTRS)

    Mc Dowall, J.; Moffat, A. J.

    1970-01-01

    Spectrometer's variable shutter permits observation of a wide range of plume widths. Adjustable grating, counter, and access window enable operator to reset grating's position during flight by resetting the counter to a predetermined number. Quartz correlation mask and spectral-aperture instrument-function filter are mounted in a replaceable precision frame.

  1. Performance of a laser frequency comb calibration system with a high-resolution solar echelle spectrograph

    NASA Astrophysics Data System (ADS)

    Doerr, H.-P.; Kentischer, T. J.; Steinmetz, T.; Probst, R. A.; Franz, M.; Holzwarth, R.; Udem, Th.; Hänsch, T. W.; Schmidt, W.

    2012-09-01

    Laser frequency combs (LFC) provide a direct link between the radio frequency (RF) and the optical frequency regime. The comb-like spectrum of an LFC is formed by exact equidistant laser modes, whose absolute optical frequencies are controlled by RF-references such as atomic clocks or GPS receivers. While nowadays LFCs are routinely used in metrological and spectroscopic fields, their application in astronomy was delayed until recently when systems became available with a mode spacing and wavelength coverage suitable for calibration of astronomical spectrographs. We developed a LFC based calibration system for the high-resolution echelle spectrograph at the German Vacuum Tower Telescope (VTT), located at the Teide observatory, Tenerife, Canary Islands. To characterize the calibration performance of the instrument, we use an all-fiber setup where sunlight and calibration light are fed to the spectrograph by the same single-mode fiber, eliminating systematic effects related to variable grating illumination.

  2. The Colorado High-Resolution Echelle Stellar Spectrograph (CHESS) Design and Status

    NASA Astrophysics Data System (ADS)

    Beasley, Matthew

    I present a new far-ultraviolet echelle spectrograph, which will provide resolving power greater than any currently existing far-ultraviolet instrument. We are using new gratings, detectors, and coatings that allow substantial advances in performance. I will present the current status of the design, and discuss known challenges and our plans to resolve them. While the design purpose of this instrument is for observations of nearby hot stars, the technologies we incorporate will allow for advances relevant to observation subjects from protoplanetary disks to the intergalactic medium. Incorporating such a spectrograph into a future, long-duration mission will make new high-quality observations possible and enhance our understanding of astrophysical plasmas.

  3. NRES: The Network of Robotic Echelle Spectrographs

    NASA Astrophysics Data System (ADS)

    Siverd, Robert; Brown, Timothy M.; Hygelund, John; Henderson, Todd; Tufts, Joseph; Eastman, Jason; Van Eyken, Julian C.; Barnes, Stuart

    2016-01-01

    Las Cumbres Observatory Global Network (LCOGT) is building the Network of Robotic Echelle Spectrographs (NRES), which will consist of six identical, optical (390 - 860 nm) high-precision spectrographs, each fiber-fed simultaneously by up to two 1-meter telescopes and a thorium argon calibration source. We plan to install one at up to 6 observatory sites in the Northern and Southern hemispheres, creating a single, globally-distributed, autonomous spectrograph facility using up to twelve 1-m telescopes. Simulations suggest we will achieve long-term radial velocity precision of 3 m/s in less than an hour for stars brighter than V = 12. We have been funded with NSF MRI and ATI grants, and expect our first spectrograph to be deployed in early 2016, with the full network operation of 5 or 6 units beginning in 2017. We will briefly overview the NRES design, goals, robotic operation, and status. In addition, we will discuss early results from our prototype spectrograph, the laboratory and on-sky performance of our first production unit, and the ongoing software development effort to bring this resource online.

  4. High-resolution grazing-incidence grating spectrometer for temperature measurements of low-Z ions emitting in the 100–300 Å spectral band

    SciTech Connect

    Widmann, K. Beiersdorfer, P.; Magee, E. W.; Boyle, D. P.; Kaita, R.; Majeski, R.

    2014-11-15

    We have constructed a high-resolution grazing-incidence spectrometer designed for measuring the ion temperature of low-Z elements, such as Li{sup +} or Li{sup 2+}, which radiate near 199 Å and 135 Å, respectively. Based on measurements at the Livermore Electron Beam Ion Trap we have shown that the instrumental resolution is better than 48 mÅ at the 200 Å setting and better than 40 mÅ for the 135-Å range. Such a high spectral resolution corresponds to an instrumental limit for line-width based temperature measurements of about 45 eV for the 199 Å Li{sup +} and 65 eV for the 135 Å Li{sup 2+} lines. Recently obtained survey spectra from the Lithium Tokamak Experiment at the Princeton Plasma Physics Laboratory show the presence of these lithium emission lines and the expected core ion temperature of approximately 70 eV is sufficiently high to demonstrate the feasibility of utilizing our high-resolution spectrometer as an ion-temperature diagnostic.

  5. Modelling high resolution Echelle spectrographs for calibrations: Hanle Echelle spectrograph, a case study

    NASA Astrophysics Data System (ADS)

    Chanumolu, Anantha; Jones, Damien; Thirupathi, Sivarani

    2015-06-01

    We present a modelling scheme that predicts the centroids of spectral line features for a high resolution Echelle spectrograph to a high accuracy. Towards this, a computing scheme is used, whereby any astronomical spectrograph can be modelled and controlled without recourse to a ray tracing program. The computations are based on paraxial ray trace and exact corrections added for certain surface types and Buchdahl aberration coefficients for complex modules. The resultant chain of paraxial ray traces and corrections for all relevant components is used to calculate the location of any spectral line on the detector under all normal operating conditions with a high degree of certainty. This will allow a semi-autonomous control using simple in-house, programming modules. The scheme is simple enough to be implemented even in a spreadsheet or in any scripting language. Such a model along with an optimization routine can represent the real time behaviour of the instrument. We present here a case study for Hanle Echelle Spectrograph. We show that our results match well with a popular commercial ray tracing software. The model is further optimized using Thorium Argon calibration lamp exposures taken during the preliminary alignment of the instrument. The model predictions matched the calibration frames at a level of 0.08 pixel. Monte Carlo simulations were performed to show the photon noise effect on the model predictions.

  6. Development of Atmospheric Chemistry Suite (ACS) for ExoMars: Three IR Spectrometers to Characterize the Atmosphere and Climate

    NASA Astrophysics Data System (ADS)

    Korablev, Oleg; Ignatiev, Nikolay; Fedorova, Anna; Trokhimovskiy, Alexander; Montmessin, Franck; Grigoriev, Alexei; Shakun, Alexey

    The Atmospheric Chemistry Suite (ACS) package is being built for the ExoMars Trace Gas Orbiter (TGO). The experiment is dedicated to study the Martian atmosphere, through sensitive measurements of minor species in solar occultations, and the monitoring of the atmospheric state in nadir. The instrument covers the spectral range from near-infrared (0.7 mum) to thermal infrared (17 mum). ACS includes three separate infrared spectrometers. The near-infrared (NIR) channel for the spectral range of 0.7-1.6 mum with resolving power of 20,000 employs the principle of an echelle spectrometer combined with an AOTF (Acousto-Optical Tuneable Filter) for order selection. The main scientific targets of NIR are the measurements of water vapor, aerosols, and dayside or nightside atmospheric emissions. The mid-infrared (MIR) channel is a high-resolution echelle instrument dedicated to solar occultation measurements in the range of 2.2-4.4 mum targeting the resolving power of 50,000. The order separation is done by means of a steerable grating cross-disperser, allowing instantaneous coverage of up to 300-nm range of the spectrum. MIR is dedicated to sensitive measurements of trace gases. The thermal-infrared channel (TIRVIM) is a 2-inch Fourier-transform spectrometer for the spectral range of 1.7-17 mum with resolution from 0.2 to 1.6 cm (-1) . TIRVIM is dedicated to monitoring of atmospheric state in nadir, and will contribute to detection/reducing of upper limits of minor species absorbing beyond 4 mum, complementing MIR. It also targets the mapping of gaseous composition in nadir. The concept of the instrument, its heritage, science objectives, and the status of development will be presented.

  7. Improved photoionization mass spectrometer

    NASA Technical Reports Server (NTRS)

    Poshchenrieder, W. P.; Samson, J. A. R.; Warneck, P.

    1970-01-01

    Improved spectrometer for gas analysis lessens the intensity problem that occurs in obtaining dispersed ultraviolet radiation. A filter, consisting of a selectively transmitting gas cell, a thin film or mirror, or a predispersing grating, alleviates problems of interference from higher-order spectral lines and from scattered ultraviolet light.

  8. Nanostructure Diffraction Gratings for Integrated Spectroscopy and Sensing

    NASA Technical Reports Server (NTRS)

    Guo, Junpeng (Inventor)

    2015-01-01

    The present disclosure pertains to metal or dielectric nanostructures of the subwavelength scale within the grating lines of optical diffraction gratings. The nanostructures have surface plasmon resonances or non-plasmon optical resonances. A linear photodetector array is used to capture the resonance spectra from one of the diffraction orders. The combined nanostructure super-grating and photodetector array eliminates the use of external optical spectrometers for measuring surface plasmon or optical resonance frequency shift caused by the presence of chemical and biological agents. The nanostructure super-gratings can be used for building integrated surface enhanced Raman scattering (SERS) spectrometers. The nanostructures within the diffraction grating lines enhance Raman scattering signal light while the diffraction grating pattern of the nanostructures diffracts Raman scattering light to different directions of propagation according to their wavelengths. Therefore, the nanostructure super-gratings allows for the use of a photodetector array to capture the surface enhanced Raman scattering spectra.

  9. Study of the image quality and stray light in the critical design phase of the Compact Echelle Spectrograph for Aeronomical Research (CESAR))

    NASA Astrophysics Data System (ADS)

    Lavigne, Jean-Franois; Doucet, Michel; Wang, Min; Lacoursire, Jean; Grill, Martin; Melchiorri, Riccardo; Slanger, Tom G.; Kendall, Elizabeth

    2010-07-01

    The success of the high resolution nightglow studies conducted with the Keck telescopes on Mauna Kea and the Very Large Telescopes in Chile led to the design of the Compact Echelle Spectrograph for Aeronomical Research (CESAR). This is an echelle spectrograph with grating post-dispersion that will be dedicated to nightglow studies at high spectral resolution (R ~ 20000) between 300-1000 nm, and that will be easily deployable at different sites. The development of CESAR is conducted by SRI International, and INO is involved in the optical design and integration of the spectrograph camera, whose all-spherical form is based on the camera of the HIRES spectrograph at the Keck I telescope. The detailed optical design is used to calculate the position of the spectral elements on the detector, predict their image quality, and estimate the level of stray light. This paper presents the methodology used in these analyses.

  10. The Polychromator: A programmable MEMS diffraction grating for synthetic spectra

    SciTech Connect

    HOCKER,G.B.; YOUNGNER,D.; BUTLER,MICHAEL A.; SINCLAIR,MICHAEL B.; PLOWMAN,THOMAS E.; DEUTSCH,E.; VOLPICELLI,A.; SENTURIA,S.; RICCO,A.J.

    2000-04-17

    The authors report here the design, fabrication and demonstration of an electrostatically actuated MEMS diffractive optical device, the Polychromator grating. The Polychromator grating enables a new type of correlation spectrometer for remote detection of a wide range of chemical species, offering electronic programmability, high specificity and sensitivity, fast response and ruggedness. Significant results include: (1) The first demonstrations of user-defined synthetic spectra in the 3-5 {micro}m wavelength regime based upon controlled deflection of individual grating elements in the Polychromator grating; (2) The first demonstration of gas detection by correlation spectroscopy using synthetic spectra generated by the Polychromator grating.

  11. FEROS: the new fiber-linked echelle spectrograph for the ESO 1.52-m telescope

    NASA Astrophysics Data System (ADS)

    Kaufer, Andreas; Pasquini, Luca

    1998-07-01

    FEROS is a new fiber-fed bench-mounted prism crossdispersed echelle spectrograph for the ESO 1.52-m telescope at the European Southern Observatory (ESO) in La Silla, Chile. It works with a 79 lines/mm R2 echelle grating in quasi-Littrow mode and in white pupil configuration. With two fibers of 100 micrometer core diameter for the object and the nearby sky, the complete optical spectrum from 370 - 860 nm is recorded in one single exposure on a 2k X 4k thinned CCD with 15 micrometer pixels. Therefore, the instrument can work in a fixed configuration on the optical bench without movable parts besides the CCD shutter mechanics. For the highest-possible opto-mechanical stability. FEROS will be housed in a temperature and humidity controlled room in the former Coude room of the telescope. The resolving power of R equals 48,000 is reached by the use of a newly designed two-slice image slicer which is fed by the two fibers. Alternatively, the sky fiber can be illuminated with a calibration lamp during the whole object exposure to monitor the spectrograph's residual motions for high-precision radial-velocity work. FEROS is built for ESO by a consortium of four European astronomical institutes under the leadership of the Landessternwarte Heidelberg, Germany. Further members of the consortium are the Astronomical Observatory Copenhagen, Denmark, the Institut d'Astrophysique de Paris, and the Observatoire de Paris/Meudon, France. It is planned that FEROS will be fully operational at the ESO 1.52-m telescope in December 1998 and will be available to the community in early 1999.

  12. Development of the Colorado High-resolution Echelle Stellar Spectrograph (CHESS)

    NASA Astrophysics Data System (ADS)

    France, Kevin; Beasley, Matthew; Kane, Robert; Nell, Nicholas; Burgh, Eric B.; Green, James C.

    2012-09-01

    A key astrophysical theme that will drive future UV/optical space missions is the life cycle of cosmic matter, from the flow of intergalactic gas into galaxies to the formation and evolution of exoplanetary systems. Spectroscopic systems capable of delivering high resolution with low backgrounds will be essential to addressing these topics. Towards this end, we are developing a rocket-borne instrument that will serve as a pathfinder for future high-sensitivity, highresolution UV spectrographs. The Colorado High-resolution Echelle Stellar Spectrograph (CHESS) will provide 2 km s-1 velocity resolution (R = 150,000) over the 100 - 160 nm bandpass that includes key atomic and molecular spectral diagnostics for the intergalactic medium (H I Lyman-series, O VI, N V, and C IV), exoplanetary atmospheres (H I Lyman-alpha, O I, and C II), and protoplanetary disks (H2 and CO electronic band systems). CHESS uses a novel mechanical collimator comprised of an array of 10 mm x 10 mm stainless steel tubes to feed a low-scatter, 69 grooves mm-1 echelle grating. The cross-disperser is a holographically ruled toroid, with 351 grooves mm-1. The spectral orders can be recorded with either a 40 mm cross-strip microchannel plate detector or a 3.5k x 3.5k δ-doped CCD. The microchannel plate will deliver 30 μm spatial resolution and employs new 64 amp/axis electronics to accommodate high count rate observations of local OB stars. CHESS is scheduled to be launched aboard a NASA Terrier/Black Brant IX sounding rocket from White Sands Missile Range in the summer of 2013.

  13. Adaptive filtering of Echelle spectra of distant Quasars

    NASA Technical Reports Server (NTRS)

    Priebe, A.; Liebscher, D.-E.; Lorenz, H.; Richter, G.-M.

    1992-01-01

    The study of the Ly alpha - forest of distant (approximately greater than 3) Quasars is an important tool in obtaining a more detailed picture of the distribution of matter along the line of sight and thus of the general distribution of matter in the Universe and is therefore of important cosmological significance. Obviously, this is one of the tasks where spectral resolution plays an important role. The spectra used were obtained with the EFOSC at the ESO 3.6m telescope. Applying for the data reduction the standard Echelle procedure, as it is implemented for instance in the MIDAS-package, one uses stationary filters (e.g. median) for noise and cosmic particle event reduction in the 2-dimensional Echelle image. These filters are useful if the spatial spectrum of the noise reaches essentially higher frequencies then the highest resolution features in the image. Otherwise the resolution in the data will be degraded and the spectral lines smoothed. However, in the Echelle spectra the highest resolution is already in the range of one or a few pixels and therefore stationary filtering means always a loss of resolution. An Echelle reduction procedure on the basis of a space variable filter described which recognizes the local resolution in the presence of noise and adapts to it is developed. It was shown that this technique leads to an improvement in resolution by a factor of 2 with respect to standard procedures.

  14. High-end spectroscopic diffraction gratings: design and manufacturing

    NASA Astrophysics Data System (ADS)

    Glaser, Tilman

    2015-02-01

    Diffraction gratings are key components for spectroscopic systems. For high-end applications, they have to meet advanced requirements as, e.g., maximum efficiency, lowest possible scattered light level, high numerical aperture, and minimal aberrations. Diffraction gratings are demanded to allow spectrometer designs with highest resolution, a maximal étendue, and minimal stray light, built within a minimal volume. This tutorial is intended to provide an overview of different high-end spectroscopic gratings, their theoretical design and manufacturing technologies.

  15. Spectroscopy of ultracold neutrons diffracted by a moving grating

    NASA Astrophysics Data System (ADS)

    Kulin, G. V.; Frank, A. I.; Goryunov, S. V.; Geltenbort, P.; Jentschel, M.; Bushuev, V. A.; Lauss, B.; Schmidt-Wellenburg, P.; Panzarella, A.; Fuchs, Y.

    2016-03-01

    Spectra of ultracold neutrons that appeared in experiments on neutron diffraction by a moving grating were measured using the time-of-flight Fourier spectrometer. Diffraction lines of five orders were observed simultaneously. The obtained data are in good agreement with the theoretical predictions based on the multiwave dynamical theory of neutron diffraction by a moving grating.

  16. H.O.R.S. a new visiting instrument for G.T.C. based on the Utrecht Echelle Spectrograph

    NASA Astrophysics Data System (ADS)

    Peate, Jos; Gracia, Felix; Allende, Carlos; Calvo, Juan; Santana, Samuel

    2014-07-01

    The High Optical Resolution Spectrograph (HORS) is a proposed high-resolution spectrograph for the 10-m Gran Telescopio Canarias (GTC) based on components from UES, a spectrograph which was in use at the 4.2-m William Herschel Telescope (WHT) between 1992 and 2001. HORS is designed as a cross-dispersed echelle spectrograph to observe in the range 380-800 nm with a FWHM resolving power of about 50,000. HORS would operate on the GTC as a general-purpose high-resolution spectrograph, and it would serve as a test-bed for some of the technologies proposed for ESPRESSO - an ultra-high stability spectrograph planned for the Very Large Telescope (VLT) of the European Southern Observatory. The HORS spectrograph will be placed in the Coud room, where it can enjoy excellent thermal and mechanical stability, fiber fed from the Nasmyth focus, which is shared with OSIRIS. Inside the spectrograph, incoming light will hit a small folder mirror before reaching the collimator. After a second folder, the light will go through a set of three prisms and an Echelle grating before entering the spectrograph camera and, finally, reaching the detector. This manuscript contains a summary of the whole process that has transformed UES into HORS, with all the mechanical and optical modifications that have been introduced to reach the final layout.

  17. Material identification employing a grating spectrometer

    DOEpatents

    Gornushkin, Ignor B.; Winefordner, James D.; Smith, Benjamin W.

    2007-01-09

    Multi-ordered spectral data is obtained from various known substances and is stored in a spectral library. The identification of an unknown material is accomplished by correlating the sample's multi-ordered spectrum against all or a portion of the spectrum in the library, and finding the closest match.

  18. Echelle spectroscopy with a charge-coupled device /CCD/

    NASA Technical Reports Server (NTRS)

    York, D. G.; Jenkins, E. B.; Zucchino, P.; Lowrance, J. L.; Long, D.; Songaila, A.

    1981-01-01

    The recent availability of large format CCD's with high quantum efficiency makes it possible to achieve significant advances in high dispersion astronomical spectroscopy. An echelle CCD combination excels or equals other techniques presently available, and offers the advantage of complete spectral coverage of several thousand Angstroms in a single exposure. Attention is given to experiments which were conducted with a CCD camera head and an echelle spectrograph on a 4-meter telescope. It was found possible to achieve a signal-to-noise ratio of 150/1 on a 13th magnitude star at 6000 A in a two-hour exposure at 0.16 A/pixel, limited primarily by photon statistics. For fainter objects, readout noise is the limiting factor in precision. For 20 electron rms readout noise, an S/N = 15/1 at 18th magnitude is expected, all other things being equal.

  19. Off-plane x-ray reflection grating fabrication

    NASA Astrophysics Data System (ADS)

    Peterson, Thomas J.; DeRoo, Casey T.; Marlowe, Hannah; McEntaffer, Randall L.; Miles, Drew M.; Tutt, James H.; Schultz, Ted B.

    2015-09-01

    Off-plane X-ray diffraction gratings with precision groove profiles at the submicron scale will be used in next generation X-ray spectrometers. Such gratings will be used on a current NASA suborbital rocket mission, the Off-plane Grating Rocket Experiment (OGRE), and have application for future grating missions. The fabrication of these gratings does not come without challenges. High performance off-plane gratings must be fabricated with precise radial grating patterns, optically at surfaces, and specific facet angles. Such gratings can be made using a series of common micro-fabrication techniques. The resulting process is highly customizable, making it useful for a variety of different mission architectures. In this paper, we detail the fabrication method used to produce high performance off-plane gratings and report the results of a preliminary qualification test of a grating fabricated in this manner. The grating was tested in the off-plane `Littrow' configuration, for which the grating is most efficient for a given diffraction order, and found to achieve 42% relative efficiency in the blaze order with respect to all diffracted light.

  20. Initial Results from the MAVEN IUVS Echelle Channel

    NASA Astrophysics Data System (ADS)

    Clarke, John T.; Mayassi, Majd; McClintock, William; Schneider, Nick; Deighan, Justin; Stewart, Ian; Holsclaw, Greg; Jakosky, Bruce

    2015-11-01

    The study of the evolution of water on Mars includes understanding the high D/ H ratio in the atmosphere and surface water today, believed to be linked to the historic loss of a large volume of primordial water (the lighter H escapes faster than the heavier D). Toward this end, the IUVS instrument on MAVEN contains the first echelle spectrograph to be sent to another planet. The system has a novel optical design to enable long-aperture measurements of emission lines in the absence of continuum, intended primarily to measure the H and D Ly ? emission lines and thereby the D/H ratio from the martian upper atmosphere. The system also detects the OI 1304 triplet with the three component lines well resolved. The specific scientific goal of the echelle channel is to measure the H and D Ly ? emissions, and to discover how the H and D densities, temperatures, and escape fluxes vary with location, season, topography, etc. Recent IR observations indicate large variations in the D/H ratio in the lower atmosphere from location to location, and possibly seasonal changes [Villanueva et al. 2015]. HST and MEX measurements of the H corona of Mars show large (order of magnitude) changes in the H exosphere and escape flux with changing seasons and/or heliospheric distance [Clarke et al. 2014 Chaffin et al. 2014]. Early results from the echelle channel regarding how these parameters apply to martian deuterium will be presented.

  1. Imaging spectrometer wide field catadioptric design

    DOEpatents

    Chrisp; Michael P. (Danville, CA)

    2008-08-19

    A wide field catadioptric imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The catadioptric design has zero Petzval field curvature. The imaging spectrometer comprises an entrance slit for transmitting light, a system with a catadioptric lens and a dioptric lens for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the system for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the system for receiving the light and the system for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light through the system for receiving the light to the detector array.

  2. Holographic optical grating and method for optimizing monochromator configuration

    DOEpatents

    Koike, Masato (Moraga, CA)

    1999-01-01

    This invention comprises a novel apparatus for recording a holographic groove pattern on a diffraction grating blank. The recording apparatus is configured using newly developed groups of analytical equations. The invention further comprises the novel holographic diffraction grating made with the inventive recording apparatus. The invention additionally comprises monochromators and spectrometers equipped with the inventive holographic diffraction grating. Further, the invention comprises a monochromator configured to reduce aberrations using a newly developed group of analytical equations. Additionally, the invention comprises a method to reduce aberrations in monochromators and spectrometers using newly developed groups of analytical equations.

  3. Atmospheric chemistry suite (ACS): a set of infrared spectrometers for atmospheric measurements on board ExoMars trace gas orbiter

    NASA Astrophysics Data System (ADS)

    Korablev, Oleg; Grigoriev, Alexei V.; Trokhimovsky, Alexander; Ivanov, Yurii S.; Moshkin, Boris; Shakun, Alexei; Dziuban, Ilia; Kalinnikov, Yurii K.; Montmessin, Franck

    2013-09-01

    The ACS package for ExoMars Trace Gas Orbiter is a part of Russian contribution to ExoMars ESA-Roscosmos mission. On the Orbiter it complements NOMAD investigation and is intended to recover in much extent the science lost with the cancellation of NASA MATMOS and EMCS infrared sounders. ACS includes three separate spectrometers, sharing common mechanical, electrical, and thermal interfaces. NIR is a versatile spectrometer for the spectral range of 0.7-1.6 ?m with resolving power of ~20000. It is conceived on the principle of RUSALKA/ISS or SOIR/Venus Express experiments combining an echelle spectrometer and an AOTF (Acousto-Optical Tuneable Filter) for order selection. Up to 8 diffraction orders, each 10-20 nm wide can be measured in one sequence record. NIR will be operated principally in nadir, but also in solar occultations, and possibly on the limb. MIR is a high-resolution echelle instrument exclusively dedicated to solar occultation measurements in the range of 2.2-4.4 ?m targeting the resolving power of 50000. The order separation is done by means of a steerable grating cross-disperser, allowing instantaneous coverage of up to 300-nm range of the spectrum for one or two records per second. MIR is dedicated to sensitive measurements of trace gases, approaching MATMOS detection thresholds for many species. TIRVIM is a 2- inch double pendulum Fourier-transform spectrometer for the spectral range of 1.7-17 ?m with apodized resolution varying from 0.2 to 1.6 cm-1. TIRVIM is primarily dedicated to monitoring of atmospheric temperature and aerosol state in nadir, and would contribute in solar occultation to detection/reducing of upper limits of some components absorbing beyond 4 ?m, complementing MIR and NOMAD. Additionally, TIRVIM targets the methane mapping in nadir, using separate detector optimized for 3.3-?m range. The concept of the instrument and in more detail the optical design and the expected parameters of its three parts, channel by channel are described.

  4. Multiple order common path spectrometer

    NASA Technical Reports Server (NTRS)

    Newbury, Amy B. (Inventor)

    2010-01-01

    The present invention relates to a dispersive spectrometer. The spectrometer allows detection of multiple orders of light on a single focal plane array by splitting the orders spatially using a dichroic assembly. A conventional dispersion mechanism such as a defraction grating disperses the light spectrally. As a result, multiple wavelength orders can be imaged on a single focal plane array of limited spectral extent, doubling (or more) the number of spectral channels as compared to a conventional spectrometer. In addition, this is achieved in a common path device.

  5. Mathematical Simulation for Integrated Linear Fresnel Spectrometer Chip

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon; Yoon, Hargoon; Lee, Uhn; King, Glen C.; Choi, Sang H.

    2012-01-01

    A miniaturized solid-state optical spectrometer chip was designed with a linear gradient-gap Fresnel grating which was mounted perpendicularly to a sensor array surface and simulated for its performance and functionality. Unlike common spectrometers which are based on Fraunhoffer diffraction with a regular periodic line grating, the new linear gradient grating Fresnel spectrometer chip can be miniaturized to a much smaller form-factor into the Fresnel regime exceeding the limit of conventional spectrometers. This mathematical calculation shows that building a tiny motionless multi-pixel microspectrometer chip which is smaller than 1 cubic millimter of optical path volume is possible. The new Fresnel spectrometer chip is proportional to the energy scale (hc/lambda), while the conventional spectrometers are proportional to the wavelength scale (lambda). We report the theoretical optical working principle and new data collection algorithm of the new Fresnel spectrometer to build a compact integrated optical chip.

  6. Imaging spectrometry using a grating in divergent light

    NASA Astrophysics Data System (ADS)

    Jones, Peter A.

    1993-09-01

    An imaging spectrometer design has been demonstrated which utilizes a plano blazed diffraction grating in divergent light. It offers important advantages over traditional collimated light spectrometers using either a grating or a prism. This design in a simple, compact configuration has linearity in wavelength and field and uniform spacing of wavelengths with no geometric distortion (smile). In addition to these features, polarization sensitivity and radiometric efficiency of the design will be discussed and compared with the requirements for the High Resolution Imaging Spectrometer (HIRIS) for the Earth Observing System.

  7. Multilayer diffraction grating

    DOEpatents

    Barbee, Jr., Troy W. (Palo Alto, CA)

    1990-01-01

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages.

  8. Diffraction gratings based on asymmetric-cut multilayers

    NASA Astrophysics Data System (ADS)

    Prasciolu, Mauro; Chapman, Henry N.; Bajt, Saša.

    2015-05-01

    We report on the fabrication of novel diffraction gratings for soft x-ray and extreme ultra-violet (EUV) photon energies based on asymmetric-cut multilayer structures. Asymmetric-cut multilayers are highly dispersive and highly efficient gratings obtained by slicing a thick multilayer coating. Multilayer deposition techniques enable sub-ångström precision in layer thickness control, which leads to close to perfect blazed gratings. However, the final grating size is limited by the maximum multilayer thickness for which one can still control the layer thickness, stress and roughness. Here, we present a new approach in which we substantially extend the grating size by combining specially prepared substrates, thick multilayer deposition and final polishing. Gratings prepared by this method, like asymmetric multilayers deposited on plane substrates, are highly dispersive and efficient. Their extended size make them ideal for use in monochromators, spectrometers and pulse compressors.

  9. Materials and Fabrication Issues for Large Machined Germanium Immersion Gratings

    SciTech Connect

    Kuzmenko, P J; Davis, P J; Little, S L; Hale, L C

    2006-05-22

    LLNL has successfully fabricated small (1.5 cm{sup 2} area) germanium immersion gratings. We studied the feasibility of producing a large germanium immersion grating by means of single point diamond flycutting. Our baseline design is a 63.4o blaze echelle with a 6 cm beam diameter. Birefringence and refractive index inhomogeneity due to stresses produced by the crystal growth process are of concern. Careful selection of the grating blank and possibly additional annealing to relieve stress will be required. The Large Optics Diamond Turning Machine (LODTM) at LLNL is a good choice for the fabrication. It can handle parts up to 1.5 meter in diameter and 0.5 meter in length and is capable of a surface figure accuracy of better than 28 nm rms. We will describe the machine modifications and the machining process for a large grating. A next generation machine, the Precision Optical Grinder and Lathe (POGAL), currently under development has tighter specifications and could produce large gratings with higher precision.

  10. Research directed toward improved echelles for the ultraviolet

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Research was undertaken to demonstrate that improved efficiencies for low frequency gratings are obtainable with the careful application of present technology. The motivation for the study was the desire to be assured that the grating-efficiency design goals for potential Space Telescope spectrographs can be achieved. The work was organized to compare gratings made with changes in the three specific parameters: the ruling tool profile, the coating material, and the lubricants used during the ruling process. A series of coatings and test gratings were fabricated and were examined for surface smoothness with a Nomarski Differential Interference Microscope and an electron microscope. Photomicrographs were obtained to show the difference in smoothness of the various coatings and rulings. Efficiency measurements were made for those test rulings that showed good groove characteristics: smoothness, proper ruling depth, and absence of defects. The intuitive feeling that higher grating efficiency should be correlated with the degree of smoothness of both the coating and the grating is supported by the results.

  11. Varied line-space gratings: past, present and future

    SciTech Connect

    Hettrick, M.C.

    1985-08-01

    A classically ruled diffraction grating consists of grooves which are equidistant, straight and parallel. Conversely, the so-called ''holographic'' grating (formed by the interfering waves of coherent visible light), although severely constrained by the recording wavelength and recording geometry, has grooves which are typically neither equidistant, straight nor parallel. In contrast, a varied line-space (VLS) grating, in common nomenclature, is a design in which the groove positions are relatively unconstrained yet possess sufficient symmetry to permit mechanical ruling. Such seemingly exotic gratings are no longer only a theoretical curiosity, but have been ruled and used in a wide variety of applications. These include: (1) aberration-corrected normal incidence concave gratings for Seya-Namioka monochromators and optical de-multiplexers, (2) flat-field grazing incidence concave gratings for plasma diagnostics, (3) aberration-corrected grazing incidence plane gratings for space-borne spectrometers, (4) focusing grazing incidence plane grating for synchrotron radiation monochromators, and (5) wavefront generators for visible interferometry of optical surfaces (particularly aspheres). Future prospects of VLS gratings as dispersing elements, wavefront correctors and beamsplitters appear promising. The author discusses the history of VLS gratings, their present applications, and their potential in the future. 61 refs., 24 figs.

  12. Full image spectral analysis of elemental emissions from an echelle spectrograph

    SciTech Connect

    Spencer, W.A.

    2000-01-27

    A new algorithm compares the background corrected echelle emission image obtained from reference standards to images of unknowns for quantitative elemental analyses. Wavelength was not used in the calculations but instead pixel position and intensity. The data reduction solution was unique to the particular detector/spectrometer. The approach was found useful for several types of images including ICP, DCP and glow discharge images. The analysis scheme required that the emission pattern of standards and background be held in memory. A dual weighting scheme was used that decreased the importance of pixels in high background areas and enhanced the importance of signals from pixels where the standards had emissions. Threshold values were used to limit the calculations to signals in the linear range of the electronics. Logarithmic weighting, (by taking the square root), was found to work well for weighting pixels from the standards. This assured that minor emissions had some influence on the data fit. In the program the best-fit scalar was determined using simple iterative guess, change and test approaches. The test looked for the minimum least square residual value in the areas of the flagged pixels.

  13. Renewable liquid reflection grating

    DOEpatents

    Ryutov, Dmitri D.; Toor, Arthur

    2003-10-07

    A renewable liquid reflection grating. Electrodes are operatively connected to a conducting liquid in an arrangement that produces a reflection grating and driven by a current with a resonance frequency. In another embodiment, the electrodes create the grating by a resonant electrostatic force acting on a dielectric liquid.

  14. Catwalk grate lifting tool

    SciTech Connect

    Gunter, Larry W.

    1992-01-01

    A device for lifting catwalk grates comprising an elongated bent member with a handle at one end and a pair of notched braces and a hook at the opposite end that act in conjunction with each other to lock onto the grate and give mechanical advantage in lifting the grate.

  15. Catwalk grate lifting tool

    DOEpatents

    Gunter, L.W.

    1992-08-11

    A device is described for lifting catwalk grates comprising an elongated bent member with a handle at one end and a pair of notched braces and a hook at the opposite end that act in conjunction with each other to lock onto the grate and give mechanical advantage in lifting the grate. 10 figs.

  16. A compact multichannel spectrometer for Thomson scatteringa)

    NASA Astrophysics Data System (ADS)

    Schoenbeck, N. L.; Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Winz, G. R.

    2012-10-01

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of Te < 100 eV are achieved by a 2971 l/mm VPH grating and measurements Te > 100 eV by a 2072 l/mm VPH grating. The spectrometer uses a fast-gated (˜2 ns) ICCD camera for detection. A Gen III image intensifier provides ˜45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  17. A compact multichannel spectrometer for Thomson scattering.

    PubMed

    Schoenbeck, N L; Schlossberg, D J; Dowd, A S; Fonck, R J; Winz, G R

    2012-10-01

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of T(e) < 100 eV are achieved by a 2971 l∕mm VPH grating and measurements T(e) > 100 eV by a 2072 l∕mm VPH grating. The spectrometer uses a fast-gated (~2 ns) ICCD camera for detection. A Gen III image intensifier provides ~45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction. PMID:23126988

  18. A compact multichannel spectrometer for Thomson scattering

    SciTech Connect

    Schoenbeck, N. L.; Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Winz, G. R.

    2012-10-15

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of T{sub e} < 100 eV are achieved by a 2971 l/mm VPH grating and measurements T{sub e} > 100 eV by a 2072 l/mm VPH grating. The spectrometer uses a fast-gated ({approx}2 ns) ICCD camera for detection. A Gen III image intensifier provides {approx}45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  19. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, Michael D. (Livermore, CA); Britten, Jerald A. (Oakley, CA); Nguyen, Hoang T. (Livermore, CA); Boyd, Robert (Livermore, CA); Shore, Bruce W. (Livermore, CA)

    1999-01-01

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described.

  20. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, M.D.; Britten, J.A.; Nguyen, H.T.; Boyd, R.; Shore, B.W.

    1999-05-25

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described. 7 figs.

  1. Surface Plasmon Based Spectrometer

    NASA Astrophysics Data System (ADS)

    Wig, Andrew; Passian, Ali; Boudreaux, Philip; Ferrell, Tom

    2008-03-01

    A spectrometer that uses surface plasmon excitation in thin metal films to separate light into its component wavelengths is described. The use of surface plasmons as a dispersive medium sets this spectrometer apart from prism, grating, and interference based variants and allows for the miniaturization of this device. Theoretical and experimental results are presented for two different operation models. In the first case surface plasmon tunneling in the near field is used to provide transmission spectra of different broad band-pass, glass filters across the visible wavelength range with high stray-light rejection at low resolution as well as absorption spectra of chlorophyll extracted from a spinach leaf. The second model looks at the far field components of surface plasmon scattering.

  2. Transmission Grating Measurements of Undulator K

    SciTech Connect

    Bionta, R. M.

    2010-12-01

    This study was undertaken to understand the practicalities of determine K differences in the undulator modules by measuring single-shot x-ray spectra of the spontaneous radiation with a transmissive grating spectrometer under development to measure FEL spectra. Since the quality of the FEL is dependent on a uniform K value in all the undulator modules, being able to measure the relative undulator K values is important. Preliminary results were presented in a presentation, 'Use of FEL Off-Axis Zone Plate Spectrometer to Measure Relative K by the Pinhole/Centroid Method', at the 'LCLS Beam-Based Undulator K Measurements Workshop' on November 14, 2005 (UCRL-PRES-217281). This study applies equally well to reflective gratings of the appropriate period and inclinations.

  3. Development of Multiple-Element Flame Emission Spectrometer Using CCD Detection

    ERIC Educational Resources Information Center

    Seney, Caryn S.; Sinclair, Karen V.; Bright, Robin M.; Momoh, Paul O.; Bozeman, Amelia D.

    2005-01-01

    The full wavelength coverage of charge coupled device (CCD) detector when coupled with an echelle spectrography, the system allows for simultaneously multiple element spectroscopy to be performed. The multiple-element flame spectrometer was built and characterized through the analysis of environmentally significant elements such as Ca, K, Na, Cu,

  4. Monolithic spectrometer

    DOEpatents

    Rajic, S.; Egert, C.M.; Kahl, W.K.; Snyder, W.B. Jr.; Evans, B.M. III; Marlar, T.A.; Cunningham, J.P.

    1998-05-19

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays. 6 figs.

  5. Monolithic spectrometer

    DOEpatents

    Rajic, Slobodan (Knoxville, TN); Egert, Charles M. (Oak Ridge, TN); Kahl, William K. (Knoxville, TN); Snyder, Jr., William B. (Knoxville, TN); Evans, III, Boyd M. (Oak Ridge, TN); Marlar, Troy A. (Knoxville, TN); Cunningham, Joseph P. (Oak Ridge, TN)

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  6. Toroidal Varied-Line Space (TVLS) Gratings

    NASA Technical Reports Server (NTRS)

    Thomas, Roger J.; Oegerle, William (Technical Monitor)

    2002-01-01

    It is a particular challenge to develop a stigmatic spectrograph for XUV wavelengths since the very low normal-incidence reflectance of standard materials most often requires that the design be restricted to a single optical element which must simultaneously provide both re-imaging and spectral dispersion. This problem has been solved in the past by the use of toroidal gratings with uniform line-spaced rulings (TULS). A number of solar EUV (Extreme Ultraviolet) spectrometers have been based on such designs, including SOHO/CDS, Solar-B/EIS, and the sounding rockets SERTS and EUNIS. More recently, Kita, Harada, and collaborators have developed the theory of spherical gratings with varied line-space rulings (SVLS) operated at unity magnification, which have been flown on several astronomical satellite missions. We now combine these ideas into a spectrometer concept that puts varied-line space rulings onto toroidal gratings. Such TVLS designs are found to provide excellent imaging even at very large spectrograph magnifications and beam-speeds, permitting extremely high-quality performance in remarkably compact instrument packages. Optical characteristics of two solar spectrometers based on this concept are described: SUMI, proposed as a sounding rocket experiment, and NEXUS, proposed for the Solar Dynamics Observatory mission.

  7. Portable smartphone optical fibre spectrometer

    NASA Astrophysics Data System (ADS)

    Hossain, Md. Arafat; Canning, John; Cook, Kevin; Jamalipour, Abbas

    2015-09-01

    A low cost, optical fibre based spectrometer has been developed on a smartphone platform for field-portable spectral analysis. Light of visible wavelength is collected using a multimode optical fibre and diffracted by a low cost nanoimprinted diffraction grating. A measurement range over 300 nm span (λ = 400 to 700 nm) is obtained using the smartphone CMOS chip. The spectral resolution is Δλ ~ 0.42 nm/screen pixel. A customized Android application processed the spectra on the same platform and shares with other devices. The results compare well with commercially available spectrometer.

  8. The GMT-CfA, Carnegie, Catolica, Chicago Large Earth Finder (G-CLEF): a general purpose optical echelle spectrograph for the GMT with precision radial velocity capability

    NASA Astrophysics Data System (ADS)

    Szentgyorgyi, A.; Frebel, A.; Furesz, G.; Hertz, E.; Norton, T.; Bean, J.; Bergner, H.; Crane, J.; Evans, J.; Evans, I.; Gauron, T.; Jordán, A.; Park, S.; Uomoto, A.; Barnes, S.; Davis, W.; Eisenhower, M.; Epps, H.; Guzman, D.; McCracken, K.; Ordway, M.; Plummer, D.; Podgorski, W.; Weaver, D.

    2012-09-01

    The GMT-CfA, Carnegie, Catolica, Chicago Large Earth Finder (G-CLEF) is a fiber fed, optical echelle spectrograph that has undergone conceptual design for consideration as a first light instrument at the Giant Magellan Telescope. GCLEF has been designed to be a general-purpose echelle spectrograph with precision radial velocity (PRV) capability. We have defined the performance envelope of G-CLEF to address several of the highest science priorities in the Decadal Survey1. The spectrograph optical design is an asymmetric, two-arm, white pupil design. The asymmetric white pupil design is adopted to minimize the size of the refractive camera lenses. The spectrograph beam is nominally 300 mm, reduced to 200 mm after dispersion by the R4 echelle grating. The peak efficiency of the spectrograph is >35% and the passband is 3500-9500Å. The spectrograph is primarily fed with three sets of fibers to enable three observing modes: High-Throughput, Precision-Abundance and PRV. The respective resolving powers of these modes are R~ 25,000, 40,000 and 120,000. We also anticipate having an R~40,000 Multi-object Spectroscopy mode with a multiplex of ~40 fibers. In PRV mode, each of the seven 8.4m GMT primary mirror sub-apertures feeds an individual fiber, which is scrambled after pupil-slicing. The goal radial velocity precision of G-CLEF is ∂V <10 cm/sec radial. In this paper, we provide a flowdown from fiducial science programs to design parameters. We discuss the optomechanical, electrical, structural and thermal design and present a roadmap to first light at the GMT.

  9. [The Study of PDMS Grating Structure Gradient Preparation Techniques].

    PubMed

    Wang, Chen-guang; Yang, Jiang-tao; Kang, Ning; Guo, Hao; Tang, Jun; Liu, Jun; Xue, Chen-yang

    2015-12-01

    Because traditional method for tunable grating fabrication has harsh process condition, complex fabrication process, high costs and long cycle. Proposed a low-cost, simple process, can be prepared in large quantities gradient grating process method, based on self-assembly process using the rigid film/flexible substrate and oxygen plasma method prepared a micron scale gradient grating. Use of plasma free time controllability and excellent elastic of PDMS obtained the desired grating. First, polyethylene terephthalate (PET) was spin-coated layer of polydimethylsiloxane (PDMS) film on the thin film, two-layer film to be cured PDMS film after bending and treated with an oxygen plasma (plasma), in generating a rigid surface oxide layer, With flexible PET rigid layer applied uniform stress, when the stress exceeds the critical value, the PDMS substrate to form a self-assembled structure grating fold. Due to changes in prestressed bending, so the PDMS film formation period and height of the grating stepped fold, which is graded grating. Using visible light as the performance test light source for graded grating and selecting first-order diffracted as the detection target. The authors can see the grating has a good diffraction effects and achieves good spectral effect. Experiments show that graded grating has obvious diffraction grating, and the diffraction angle varies significantly, and can be widely used for stress measurement, the flexible gradient grating prepared by this method can also be used to detect changes in the stress strain as a miniature device, the future is expected for miniature spectrometer, scanners, optical communications and other fields. PMID:26964244

  10. Pseudoslit Spectrometer

    NASA Technical Reports Server (NTRS)

    Reuter, Dennis C.; McCabe, George H.

    2004-01-01

    The pseudoslit spectrometer is a conceptual optoelectronic instrument that would offer some of the advantages, without the disadvantages, of prior linear-variable etalon (LVE) spectrometers and prior slit spectrometers. The pseudoslit spectrometer is so named because it would not include a slit, but the combined effects of its optical components would include a spatial filtering effect approximately equivalent to that of a slit. Like a prior LVE spectrometer, the pseudoslit spectrometer would include an LVE (essentially, a wedge-like narrowband- pass filter, the pass wavelength of which varies linearly with position in one dimension) in a focal plane covering an imaging planar array of photodetectors. However, the pseudoslit spectrometer would be more efficient because unlike a prior LVE spectrometer, the pseudoslit spectrometer would not have to be scanned across an entire field of view to obtain the spectrum of an object of interest that may occupy only a small portion of the field of view. Like a prior slit spectrometer, the pseudoslit spectrometer could acquire the entire spectrum of such a small object without need for scanning. However, the pseudoslit spectrometer would be optically and mechanically simpler: it would have fewer components and, hence, would pose less of a problem of alignment of components and would be less vulnerable to misalignment.

  11. Reflective diffraction grating

    DOEpatents

    Lamartine, Bruce C. (Los Alamos, NM)

    2003-06-24

    Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.

  12. Biopolymer holographic diffraction gratings

    NASA Astrophysics Data System (ADS)

    Savi? evi?, Svetlana; Panteli?, Dejan

    2008-03-01

    Surface-relief diffraction gratings are holographically recorded in dextran sensitized with ammonium dichromate (DCD). DCD was exposed with single-frequency 200 mW diode pumped ND-YAG laser, at 532 nm. The diffraction grating profiles were analyzed by atomic force microscopy (AFM). It was found that different surface profiles could be obtained. Gratings with 330 lines/mm spatial frequencies were made. Existence of higher harmonics in Fourier Transform of non-sinusoidal profiles shows that DCD is capable of recording spatial frequencies up to 1320 lines/mm (four times fundamental frequency). The measured maximum relief depth of the DCD grating is 402 nm.

  13. The fabrication of toroidal and coma-corrected toroidal diffraction gratings from spherical master gratings using elastically-deformable substrates - A progress report

    NASA Technical Reports Server (NTRS)

    Huber, Martin C. E.; Timothy, J. G.; Morgan, Jeffrey S.; Lemaitre, Gerard; Tondello, Giuseppe; Naletto, Giampiero

    1991-01-01

    A technique has been developed which permits toroidal, and coma-corrected toroidal, diffraction gratings to be replicated from spherical master gratings by the use of elastically-deformable substrates. Toroidal gratings correct for astigmatism and, thus, make it possible to construct stigmatic spectrometers that employ a single reflective diffraction grating. These spectrometers are particularly useful for the extreme-ultraviolet (EUV) wavelength range, where reflection coefficients are low, since the single optical surface provides for dispersion, focusing, and astigmatism correction. The fabrication procedures for the pure toroidal, and coma-corrected toroidal, gratings are described, and initial test results are presented. The use of the toroidal gratings in a high-resolution sounding-rocket EUV spectroheliometer, and in both the coronal diagnostics spectrometer and the ultraviolet coronagraph spectrometer on the ESA/NASA solar and heliospheric observatory mission, is described briefly, and the use of this technique for the fabrication of a coma-corrected toroidal grating for the prime Rowland spectrograph of the FUSE/Lyman mission is briefly discussed.

  14. Deformed ellipsoidal diffraction grating blank

    NASA Technical Reports Server (NTRS)

    Decew, Alan E., Jr.

    1994-01-01

    The Deformed Ellipsoidal Grating Blank (DEGB) is the primary component in an ultraviolet spectrometer. Since one of the major concerns for these instruments is throughput, significant efforts are made to reduce the number of components and subsequently reflections. Each reflection results in losses through absorption and scattering. It is these two sources of photon loss that dictated the requirements for the DEGB. The first goal is to shape the DEGB in such a way that the energy at the entrance slit is focused as well as possible on the exit slit. The second goal is to produce a surface smooth enough to minimize the photon loss due to scattering. The program was accomplished in three phases. The first phase was the fabrication planning. The second phase was the actual fabrication and initial testing. The last phase was the final testing of the completed DEGB.

  15. Calibrating echelle spectrographs with Fabry-Pérot etalons

    NASA Astrophysics Data System (ADS)

    Bauer, F. F.; Zechmeister, M.; Reiners, A.

    2015-09-01

    Context. Over the past decades hollow-cathode lamps have been calibration standards for spectroscopic measurements. Advancing to cm/s radial velocity precisions with the next generation of instruments requires more suitable calibration sources with more lines and fewer dynamic range problems. Fabry-Pérot interferometers provide a regular and dense grid of lines and homogeneous amplitudes, which makes them good candidates for next-generation calibrators. Aims: We investigate the usefulness of Fabry-Pérot etalons in wavelength calibration, present an algorithm to incorporate the etalon spectrum in the wavelength solution, and examine potential problems. Methods: The quasi-periodic pattern of Fabry-Pérot lines was used along with a hollow-cathode lamp to anchor the numerous spectral features on an absolute scale. We tested our method with the HARPS spectrograph and compared our wavelength solution to the one derived from a laser frequency comb. Results: The combined hollow-cathode lamp/etalon calibration overcomes large distortion (50 m/s) in the wavelength solution of the HARPS data reduction software. The direct comparison to the laser frequency comb shows differences of only 10 m/s at most. Conclusions: Combining hollow-cathode lamps with Fabry-Pérot interferometers can lead to substantial improvements in the wavelength calibration of echelle spectrographs. Etalons can provide economical alternatives to the laser frequency comb, especially for smaller projects.

  16. Design and Construction of VUES: The Vilnius University Echelle Spectrograph

    NASA Astrophysics Data System (ADS)

    Jurgenson, Colby; Fischer, Debra; McCracken, Tyler; Sawyer, David; Giguere, Matt; Szymkowiak, Andrew; Santoro, Fernando; Muller, Gary

    2016-03-01

    In February 2014, the Yale Exoplanet Laboratory was commissioned to design, build, and deliver a high resolution (R=60,000) spectrograph for the 1.65m telescope at the Molėtai Astronomical Observatory. The observatory is operated by the Institute of Theoretical Physics and Astronomy at Vilnius University. The Vilnius University Echelle Spectrograph (VUES) is a white-pupil design that is fed via an octagonal fiber from the telescope and has an operational bandpass from 400nm to 880nm. VUES incorporates a novel modular optomechanical design that allows for quick assembly and alignment on commercial optical tables. This approach allowed the spectrograph to be assembled and commissioned at Yale using lab optical tables and then reassembled at the observatory on a different optical table with excellent repeatability. The assembly and alignment process for the spectrograph was reduced to a few days, allowing the spectrograph to be completely disassembled for shipment to Lithuania, and then installed at the observatory during a 10-day period in June of 2015.

  17. Utrecht Echelle spectroscopy of a flare in VB 8

    NASA Astrophysics Data System (ADS)

    Martn, E. L.

    1999-01-01

    Very high-resolution (R ~ 110 000) spectroscopic observations of the very low-mass star VB 8, obtained with the Utrecht Echelle spectrograph (UES), are presented. A flare occurred during the third of a series of four consecutive spectra. This event produced significant enhancement in the strength of the emission lines of He i D3 and H? in VB 8, as well as a filling up of some but not all atomic absorption lines, and a weakening of the ? TiO bandheads at 705.4 and 712.5 nm. Core emission in the Na i D1, D2 and K i 769.9-nm resonance lines also became stronger during the flare. Other very low-mass stars observed with the same instrumental configuration include GJ 406 and VB 10. The UES spectrum of VB 8 is compared with these. In particular, VB 10 appears to have a lower gravity than VB 8, indicating a lower age and a smaller mass which could be very close to the substellar mass limit for solar metallicity.

  18. ORFEUS II echelle spectra: H_2 absorption in SMC gas

    NASA Astrophysics Data System (ADS)

    Richter, P.; Widmann, H.; de Boer, K. S.; Appenzeller, I.; Barnstedt, J.; Goelz, M.; Grewing, M.; Gringel, W.; Kappelmann, N.; Kraemer, G.; Mandel, H.; Werner, K.

    We present a study of H_2 in the SMC gas, based on space shuttle Far UV spectroscopy with ORFEUS and the Tue/HD echelle spectrograph, in the line of sight to the SMC star HD 5980. 17 absorption lines from the Lyman band have been analysed. Our line of sight crosses two clouds within the SMC. We detect a cool molecular component near +120 km s^{-1}, where the H_2 from the lowest 3 rotational states (J <= 2) is found. For this cloud we derive an excitation temperature of ~= 70 K, probably the kinetic temerature of the gas. The cloud is located in the SMC foreground. Another SMC component is visible at +160 km s^{-1}. Here we find unblended H_2 absorption lines from levels 5 <= J <= 7. For this component we obtain an equivalent excitation temperature Tex > 2350 K and conclude that this cloud must be highly excited by strong UV radiation from its energetic environment. (Research supported in part by the DARA)

  19. AVES: an adaptive optics visual echelle spectrograph for the VLT

    NASA Astrophysics Data System (ADS)

    Pasquini, Luca; Delabre, Bernard; Avila, Gerardo; Bonaccini, Domenico

    1998-07-01

    We present the preliminary study of a low cost, high performance spectrograph for the VLT, for observations in the V, R and I bands. This spectrograph is meant for intermediate (R equals 16,000) resolution spectroscopy of faint (sky and/or detector limited) sources, with particular emphasis on the study of solar-type (F-G) stars belonging to the nearest galaxies and to distant (or highly reddened) galactic clusters. The spectrograph is designed to use the adaptive optics (AO) systems at the VLT Telescope. Even if these AO systems will not provide diffraction limited images in the V, R and I bands, the photon concentration will still be above approximately 60% of the flux in an 0.3 arcsecond aperture for typical Paranal conditions. This makes the construction of a compact, cheap and efficient echelle spectrograph possible. AVES will outperform comparable non adaptive optic instruments by more than one magnitude for sky- and/or detector-limited observations, and it will be very suitable for observations in crowded fields.

  20. Correlation spectrometer

    DOEpatents

    Sinclair, Michael B. (Albuquerque, NM); Pfeifer, Kent B. (Los Lunas, NM); Flemming, Jeb H. (Albuquerque, NM); Jones, Gary D. (Tijeras, NM); Tigges, Chris P. (Albuquerque, NM)

    2010-04-13

    A correlation spectrometer can detect a large number of gaseous compounds, or chemical species, with a species-specific mask wheel. In this mode, the spectrometer is optimized for the direct measurement of individual target compounds. Additionally, the spectrometer can measure the transmission spectrum from a given sample of gas. In this mode, infrared light is passed through a gas sample and the infrared transmission signature of the gasses present is recorded and measured using Hadamard encoding techniques. The spectrometer can detect the transmission or emission spectra in any system where multiple species are present in a generally known volume.

  1. The diffraction grating in the Ivory optomechanical modeling tools

    NASA Astrophysics Data System (ADS)

    Hatheway, Alson E.

    2013-09-01

    In imaging spectrometers it is important that both the image of the far-field object and the image of the slit be stable on the detector plane. Lenses and mirrors contribute to the motions of these images but motions of the diffraction grating also have their own influences on these image motions. This paper develops the vector equations for the images (spectra) of the diffraction grating and derives their optomechanical influence coefficients from them. The Ivory Optomechanical Modeling Tools integrates the diffraction grating into the larger optical imaging system and formats the whole system's influence coefficients suitably for both spreadsheet and finite element analysis methods. Their application is illustrated in an example of a spectrometer exposed to both static and dynamic disturbances.

  2. Micro spectrometer for parallel light and method of use

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2011-01-01

    A spectrometer system includes an optical assembly for collimating light, a micro-ring grating assembly having a plurality of coaxially-aligned ring gratings, an aperture device defining an aperture circumscribing a target focal point, and a photon detector. An electro-optical layer of the grating assembly may be electrically connected to an energy supply to change the refractive index of the electro-optical layer. Alternately, the gratings may be electrically connected to the energy supply and energized, e.g., with alternating voltages, to change the refractive index. A data recorder may record the predetermined spectral characteristic. A method of detecting a spectral characteristic of a predetermined wavelength of source light includes generating collimated light using an optical assembly, directing the collimated light onto the micro-ring grating assembly, and selectively energizing the micro-ring grating assembly to diffract the predetermined wavelength onto the target focal point, and detecting the spectral characteristic using a photon detector.

  3. Multidimensional spectrometer

    DOEpatents

    Zanni, Martin Thomas (Madison, WI); Damrauer, Niels H. (Boulder, CO)

    2010-07-20

    A multidimensional spectrometer for the infrared, visible, and ultraviolet regions of the electromagnetic spectrum, and a method for making multidimensional spectroscopic measurements in the infrared, visible, and ultraviolet regions of the electromagnetic spectrum. The multidimensional spectrometer facilitates measurements of inter- and intra-molecular interactions.

  4. Performance characterization of the reflection grating arrays (RGA) for the RGS experiment aboard XMM

    NASA Astrophysics Data System (ADS)

    Rasmussen, Andrew; Cottam, Jean; Decker, Todd A.; Kahn, Steven M.; Spodek, Joshua; Stern, M.; Erd, Christian; den Boggende, Antonius J.; Brinkman, Albert C.; den Herder, Jan-Willem; Paerels, Frits B.; Vries, C. D.

    1998-11-01

    The Reflection Grating Spectrometer (RGS) aboard XMM is a large collecting area, dispersive soft x-ray spectrometer providing high resolution and a bandpass of 5-35 angstrom. We have built and characterized the two, nearly identical, flight model reflection grating arrays for the RGS instrument. Precision alignment and assembly of 182 grating elements into each array was performed at Columbia Astrophysics/Nevis Laboratory, and end-to-end X-ray calibration and testing were performed at the MPE-Panter facility. Preliminary results from the calibration are summarized, and reconciliation of those results with baseline optical design, simulations and error budgets are discussed.

  5. Transmitted wavefront error of a volume phase holographic grating at cryogenic temperature.

    PubMed

    Lee, David; Taylor, Gordon D; Baillie, Thomas E C; Montgomery, David

    2012-06-01

    This paper describes the results of transmitted wavefront error (WFE) measurements on a volume phase holographic (VPH) grating operating at a temperature of 120 K. The VPH grating was mounted in a cryogenically compatible optical mount and tested in situ in a cryostat. The nominal root mean square (RMS) wavefront error at room temperature was 19 nm measured over a 50 mm diameter test aperture. The WFE remained at 18 nm RMS when the grating was cooled. This important result demonstrates that excellent WFE performance can be obtained with cooled VPH gratings, as required for use in future cryogenic infrared astronomical spectrometers planned for the European Extremely Large Telescope. PMID:22660099

  6. Aberrations of varied line-space grazing incidence gratings in converging light beams

    NASA Technical Reports Server (NTRS)

    Hettrick, M. C.

    1984-01-01

    Analyses of the imaging properties of several designs for varied-line space gratings in converging beams of light in grazing-incidence spectrometers are presented. An explicit model is defined for the case of a plane-reflection grating intercepting light that converges and is reflected to a stigmatic point associated with the zero-order image of the grating. Smooth spatial variation of the grating constant then permits aberration correction. The aberrations are expressed as polynomials in the grating lens coordinates using power series expansions. Application of the model is illustrated in terms of aberrations experienced with the short wavelength spectrometer on the EUVE satellite. Attention is given to straight and parallel in-plane grooves, curved groove in-plane designs and off-plane grooves. Aberrations due to dispersions and misalignment are also considered.

  7. Galileo Ultraviolet Spectrometer experiment

    NASA Technical Reports Server (NTRS)

    Hord, C. W.; Mcclintock, W. E.; Stewart, A. I. F.; Barth, C. A.; Esposito, L. W.; Thomas, G. E.; Sandel, B. R.; Hunten, D. M.; Broadfoot, A. L.; Shemansky, D. E.

    1992-01-01

    The Galileo ultraviolet spectrometer experiment uses data obtained by the Ultraviolet Spectrometer (UVS) mounted on the pointed orbiter scan platform and from the Extreme Ultraviolet Spectrometer (EUVS) mounted on the spinning part of the orbiter with the field of view perpendicular to the spin axis. The UVS is a Ebert-Fastie design that covers the range 113-432 nm with a wavelength resolution of 0.7 nm below 190 and 1.3 nm at longer wavelengths. The UVS spatial resolution is 0.4 deg x 0.1 deg for illuminated disk observations and 1 deg x 0.1 deg for limb geometries. The EUVS is a Voyager design objective grating spectrometer, modified to cover the wavelength range from 54 to 128 nm with wavelength resolution 3.5 nm for extended sources and 1.5 nm for point sources and spatial resolution of 0.87 deg x 0.17 deg. The EUVS instrument will follow up on the many Voyager UVS discoveries, particularly the sulfur and oxygen ion emissions in the Io torus and molecular and atomic hydrogen auroral and airglow emissions from Jupiter. The UVS will obtain spectra of emission, absorption, and scattering features in the unexplored, by spacecraft, 170-432 nm wavelength region. The UVS and EUVS instruments will provide a powerful instrument complement to investigate volatile escape and surface composition of the Galilean satellites, the Io plasma torus, micro- and macro-properties of the Jupiter clouds, and the composition structure and evolution of the Jupiter upper atmosphere.

  8. Performance of high spatial frequency X-ray transmission gratings

    NASA Technical Reports Server (NTRS)

    Fischbach, K. F.; Levine, A. M.; Schattenburg, M. L.; Dewey, D.; Renshaw, R. L.

    1988-01-01

    The performance of high spatial frequency 'phased' X-ray transmission gratings developed for the High Energy Transmission Grating Spectrometer on the Advanced X-ray Astrophysics FAcility (AXAF) is examined. The gratings tested here nominally consist of 1-micron-thick gold lines of 0.2 micron period covering approximately 5 sq cm of a polyimide membrane. A table-top setup at MIT employs the gratings in reflection to diffract UV (325 nm) laser light. It is used to measure grating periods and indicates that period variations within and between gratings are a few parts in 10,000. Tests performed at the Marshall Space Flight Center 304 m X-ray Facility using 1.5 keV X-rays in transmission corroborate the UV measurements and demonstrate geometrically-limited resolving powers of E/Delta E about 750. Finally, X-ray transmission tests performed in the MIT 25 m X-ray facility provide measurements of period, line thickness, space-to-period ratio, tilt of grating lines, and efficiency.

  9. Automatic one dimensional spectra extraction for Weihai fiber-fed high resolution echelle spectra

    NASA Astrophysics Data System (ADS)

    Hu, Shao Ming; Gao, Dong Yang

    2014-11-01

    One fiber-fed high resolution echelle spectrograph was built for the one meter telescope atWeihai Observatory of Shandong University. It is used for exoplanet searching by radial velocity method and for stellar spectra analysis. One dimensional spectra extraction from the raw echelle data is researched in this paper. Flat field images with different exposure times were used to trace the order position accurately. The accurate background was fitted from each CCD image and it was subtracted from the raw image to correct the background and straylight. The intensity of each order decreases towards the order margin, and the lengths of order are different between the blue and red regions. The order tracing during the data reduction was investigated in this work. Accurate flux can be obtained after considering the effects of bad pixels, the curvature of each order and so on. One Interactive Data Language program for one dimensional spectra extraction was adopted and implemented to echelle data reduction for Weihai fiber-fed high resolution echelle spectra, and the results are illustrated here. The program is efficient and accurate for echelle data reduction. It can be adopted to reduce data taken by other instruments even the spectrographs in other fields, and it is very convenient for astronomers.

  10. Color separation gratings

    NASA Technical Reports Server (NTRS)

    Farn, Michael W.; Knowlden, Robert E.

    1993-01-01

    In this paper, we describe the theory, fabrication and test of a binary optics 'echelon'. The echelon is a grating structure which separates electromagnetic radiation of different wavelengths, but it does so according to diffraction order rather than by dispersion within one diffraction order, as is the case with conventional gratings. A prototype echelon, designed for the visible spectrum, is fabricated using the binary optics process. Tests of the prototype show good agreement with theoretical predictions.

  11. CAFE: Calar Alto Fiber-fed Echelle spectrograph

    NASA Astrophysics Data System (ADS)

    Sánchez, S. F.; Aceituno, J.; Thiele, U.; Grupp, F.; Dreizler, S.; Bean, J.; Benitez, D.

    2011-11-01

    The Calar Alto Fiber-fed Echelle spectrograph (CAFE) is an instrument underconstruction at CAHA to replace FOCES, the high-resolution echellespectrograph at the 2.2 m telescope of the observatory. FOCES is a property ofthe Observatory of the Munich University, and it was recalled it from Calar Altoin 2009. The instrument comprised a substantial fraction of thetelescope time during its operational life-time, and it is due to that it wastaken the decision to build a replacement.CAFE shares its basic characteristics with those of FOCES. However, significantimprovements have been introduced in the original design, the quality of thematerials, and the overall stability of the system. In particular: (i) a newcalibration Iodine cell is foreseen to operate together with the standard ThArlamps; (ii) the optical quality of all the components has been selected to belambda/20, instead of the original lambda/10; (iii) an isolated room hasbeen selected to place the instrument, termalized and stabilized againstvibrations (extensive tests have been performed to grant the stability); (iv)most of the mobile parts in FOCES has been substituted by fixed elements, toincrease the stability of the system; and finally (v) a new more efficientCCD, with a smaller pixel has been acquired. It is expected that the overallefficiency and the quality of the data will be significantly improved withrespect to its precesor. In particular, CAFE is design and built to achieveresolutions of R ˜ 70000, which will be kept in the final acquired data,allowing it to compete with current operational extrasolar planets hunters.After two years of work all the components are in place. The instrument is nowfinally assembled, and we are performing the the first alignment tests. It isexpected that the commissioning on the laboratory will finish at the end of2010, followed by the commissioning on telescope along the first semester of2011. If everything goes well, we will offer the instrument in a shared-riskmode for the second semester of 2011.

  12. Performance of volume phase holographic transmission grating recorded in DCG for PGP

    NASA Astrophysics Data System (ADS)

    Li, Ming; Tang, Minxue; Xia, Haohan; Fang, Chunhuan; Wu, Jianhong; Zhao, Xunjie

    2010-11-01

    The volume phase holographic (VPH) transmission grating recorded in dichromate gelatin (DCG) with a specific spectral coverage from 420 nm to 760 nm is designed for a novel prism-grating-prism imaging spectrometer. Based on the Rigorous Coupled-Wave Analysis, its performances are predicted and analyzed. The grating is manufactured and its properties are measured experimentally. The diffraction efficiency over the spectral range, the bandwidth, and the angular selectivity of the grating is measured, analyzed and compared with that of the theoretical ones. The results show that by adjusting and controlling the preparation conditions of DCG plates, the exposure time and the post-processing technique of the grating, the VPH transmission grating with high diffraction efficiency approximate to the design requirement can be obtained. The measured peak diffraction efficiency reaches nearly 85% at central wavelength of 590 nm while the average diffraction efficiency is larger than 75% over the required spectral range from 420 nm to 760 nm.

  13. Dual waveband compact catadioptric imaging spectrometer

    DOEpatents

    Chrisp, Michael P.

    2012-12-25

    A catadioptric dual waveband imaging spectrometer that covers the visible through short-wave infrared, and the midwave infrared spectral regions, dispersing the visible through shortwave infrared with a zinc selenide grating and midwave infrared with a sapphire prism. The grating and prism are at the cold stop position, enabling the pupil to be split between them. The spectra for both wavebands are focused onto the relevant sections of a single dual waveband detector. Spatial keystone distortion is controlled to less than one tenth of a pixel over the full wavelength range, facilitating the matching of the spectra in the midwave infrared with the shorter wavelength region.

  14. High performance Si immersion gratings patterned with electron beam lithography

    NASA Astrophysics Data System (ADS)

    Gully-Santiago, Michael A.; Jaffe, Daniel T.; Brooks, Cynthia B.; Wilson, Daniel W.; Muller, Richard E.

    2014-07-01

    Infrared spectrographs employing silicon immersion gratings can be significantly more compact than spectro- graphs using front-surface gratings. The Si gratings can also offer continuous wavelength coverage at high spectral resolution. The grooves in Si gratings are made with semiconductor lithography techniques, to date almost entirely using contact mask photolithography. Planned near-infrared astronomical spectrographs require either finer groove pitches or higher positional accuracy than standard UV contact mask photolithography can reach. A collaboration between the University of Texas at Austin Silicon Diffractive Optics Group and the Jet Propulsion Laboratory Microdevices Laboratory has experimented with direct writing silicon immersion grating grooves with electron beam lithography. The patterning process involves depositing positive e-beam resist on 1 to 30 mm thick, 100 mm diameter monolithic crystalline silicon substrates. We then use the facility JEOL 9300FS e-beam writer at JPL to produce the linear pattern that defines the gratings. There are three key challenges to produce high-performance e-beam written silicon immersion gratings. (1) E- beam field and subfield stitching boundaries cause periodic cross-hatch structures along the grating grooves. The structures manifest themselves as spectral and spatial dimension ghosts in the diffraction limited point spread function (PSF) of the diffraction grating. In this paper, we show that the effects of e-beam field boundaries must be mitigated. We have significantly reduced ghost power with only minor increases in write time by using four or more field sizes of less than 500 ?m. (2) The finite e-beam stage drift and run-out error cause large-scale structure in the wavefront error. We deal with this problem by applying a mark detection loop to check for and correct out minuscule stage drifts. We measure the level and direction of stage drift and show that mark detection reduces peak-to-valley wavefront error by a factor of 5. (3) The serial write process for typical gratings yields write times of about 24 hours- this makes prototyping costly. We discuss work with negative e-beam resist to reduce the fill factor of exposure, and therefore limit the exposure time. We also discuss the tradeoffs of long write-time serial write processes like e-beam with UV photomask lithography. We show the results of experiments on small pattern size prototypes on silicon wafers. Current prototypes now exceed 30 dB of suppression on spectral and spatial dimension ghosts compared to monochromatic spectral purity measurements of the backside of Si echelle gratings in reflection at 632 nm. We perform interferometry at 632 nm in reflection with a 25 mm circular beam on a grating with a blaze angle of 71.6. The measured wavefront error is 0.09 waves peak to valley.

  15. HyTES: Thermal Imaging Spectrometer Development

    NASA Technical Reports Server (NTRS)

    Johnson, William R.; Hook, Simon J.; Mouroulis, Pantazis; Wilson, Daniel W.; Gunapala, Sarath D.; Realmuto, Vincent; Lamborn, Andy; Paine, Chris; Mumolo, Jason M.; Eng, Bjorn T.

    2011-01-01

    The Jet Propulsion Laboratory has developed the Hyperspectral Thermal Emission Spectrometer (HyTES). It is an airborne pushbroom imaging spectrometer based on the Dyson optical configuration. First low altitude test flights are scheduled for later this year. HyTES uses a compact 7.5-12 micrometer m hyperspectral grating spectrometer in combination with a Quantum Well Infrared Photodetector (QWIP) and grating based spectrometer. The Dyson design allows for a very compact and optically fast system (F/1.6). Cooling requirements are minimized due to the single monolithic prism-like grating design. The configuration has the potential to be the optimal science-grade imaging spectroscopy solution for high altitude, lighter-than-air (HAA, LTA) vehicles and unmanned aerial vehicles (UAV) due to its small form factor and relatively low power requirements. The QWIP sensor allows for optimum spatial and spectral uniformity and provides adequate responsivity which allows for near 100mK noise equivalent temperature difference (NEDT) operation across the LWIR passband. The QWIP's repeatability and uniformity will be helpful for data integrity since currently an onboard calibrator is not planned. A calibration will be done before and after eight hour flights to gage any inconsistencies. This has been demonstrated with lab testing. Further test results show adequate NEDT, linearity as well as applicable earth science emissivity target results (Silicates, water) measured in direct sunlight.

  16. [Development of X-ray Reflection Grating Technology for the Constellation-X Mission

    NASA Technical Reports Server (NTRS)

    Schattenburg, Mark L.

    2005-01-01

    This Grant supports MIT technology development of x-ray reflection gratings for the Constellation-X Reflection Grating Spectrometer (RGS). Since the start of the Grant MIT has extended its previously-developed patterning and super-smooth, blazed grating fabrication technology to ten-times smaller grating periods and ten-times larger blaze angles to demonstrate feasibility and performance in the off-plane grating geometry. In the past year we have focused our efforts on extending our Nanoruler grating fabrication tool to enable it to perform variable-period scanning-beam interference lithography (VP-SBIL). This new capability required extensive optical and mechanical improvements to the system. The design phase of this work is largely completed and key components are now on order and assembly has begun. Over the next several months the new VP-SBIL Nanoruler system will be completed and testing begun. We have also demonstrated a new technique for patterning gratings using the Nanoruler called Doppler mode, which will be important for patterning the radial groove gratings for the RGS using the new VP-SBIL system. Flat and thin grating substrates will be critical for the RGS. In the last year we demonstrated a new technique for flattening thin substrates using magneto-rheologic fluid polishing (MRF) and achieved 2 arcsecond flatness with a 0.5 mm-thick substrate-a world's record. This meets the Con X requirement for grating substrate flatness.

  17. New family of reflective spectrometers

    NASA Astrophysics Data System (ADS)

    Romoli, Andrea; Simonetti, Francesca; Gambicorti, Lisa; Marchi, Alessandro Zuccaro

    2011-01-01

    Three kinds of spectrometers based on off-axis Schmidt and Schmidt-Cassegrain cameras are presented; they have been used for several instruments studies, mainly for European Space Agency and Agenzia Spaziale Italiana. Both dispersive prism and grating based configurations have interesting characteristics, such as: simplicity, low cost, high efficiency, small volume and weight, very low sensitivity to polarization and great flexibility also in multichannel (wavebands) configurations. The image quality is high, even with low relative apertures and great fields of view, allowing a very good correction of smile and keystone. The compensation of the slit curvature induced by a prism disperser is also demonstrated. This family of spectrometers was the topic of three patents, belonging to Selex-Galileo, while the intellectual property belongs to A. Romali et al.

  18. Concerning the Spatial Heterodyne Spectrometer.

    PubMed

    Lenzner, Matthias; Diels, Jean-Claude

    2016-01-25

    A modified Spatial Heterodyne Spectrometer (SHS) is used for measuring atomic emission spectra with high resolution. This device is basically a Fourier Transform Spectrometer, but the Fourier transform is taken in the directions perpendicular to the optical propagation and heterodyned around one preset wavelength. In recent descriptions of this device, one specific phenomenon - the tilt of the energy front of wave packets when diffracted from a grating - was neglected. This led to an overestimate of the resolving power of this spectrograph, especially in situations when the coherence length of the radiation under test is in the order of the effective aperture of the device. The limits of usability are shown here together with some measurements of known spectral lines. PMID:26832561

  19. Concerning the Spatial Heterodyne Spectrometer

    DOE PAGESBeta

    Lenzner, Matthias; Diels, Jean -Claude

    2016-01-22

    A modified Spatial Heterodyne Spectrometer (SHS) is used for measuring atomic emission spectra with high resolution. This device is basically a Fourier Transform Spectrometer, but the Fourier transform is taken in the directions perpendicular to the optical propagation and heterodyned around one preset wavelength. In recent descriptions of this device, one specific phenomenon - the tilt of the energy front of wave packets when diffracted from a grating - was neglected. This led to an overestimate of the resolving power of this spectrograph, especially in situations when the coherence length of the radiation under test is in the order ofmore » the effective aperture of the device. In conclusion, the limits of usability are shown here together with some measurements of known spectral lines.« less

  20. Unexpected effects of a trap in CCD echelle spectra of B-type stars

    NASA Technical Reports Server (NTRS)

    Morrison, Nancy D.; Zimba, Jason R.

    1990-01-01

    Because of the nature of echelle spectra, cosmetic defects such as traps may mimic real spectral features. An example from spectra taken at CTIO with a GEC CCD is presented, and it is shown how the affected pixels can be eliminated from the reduced spectrum, at a slight cost in signal-to-noise ratio.

  1. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B. (Shoreham, NY)

    1986-01-01

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  2. Birefringence Bragg Binary (3B) grating, quasi-Bragg grating and immersion gratings

    NASA Astrophysics Data System (ADS)

    Ebizuka, Noboru; Morita, Shin-ya; Yamagata, Yutaka; Sasaki, Minoru; Bianco, Andorea; Tanabe, Ayano; Hashimoto, Nobuyuki; Hirahara, Yasuhiro; Aoki, Wako

    2014-07-01

    A volume phase holographic (VPH) grating achieves high angular dispersion and very high diffraction efficiency for the first diffraction order and for S or P polarization. However the VPH grating could not achieve high diffraction efficiency for non-polarized light at a large diffraction angle because properties of diffraction efficiencies for S and P polarizations are different. Furthermore diffraction efficiency of the VPH grating extinguishes toward a higher diffraction order. A birefringence binary Bragg (3B) grating is a thick transmission grating with optically anisotropic material such as lithium niobate or liquid crystal. The 3B grating achieves diffraction efficiency up to 100% for non-polarized light by tuning of refractive indices for S and P polarizations, even in higher diffraction orders. We fabricated 3B grating with liquid crystal and evaluated the performance of the liquid crystal grating. A quasi-Bragg (QB) grating, which consists long rectangle mirrors aligned in parallel precisely such as a window shade, also achieves high diffraction efficiency toward higher orders. We fabricated QB grating by laminating of silica glass substrates and glued by pressure fusion of gold films. A quasi-Bragg immersion (QBI) grating has smooth mirror hypotenuse and reflector array inside the hypotenuse, instead of step-like grooves of a conventional immersion grating. An incident beam of the QBI grating reflects obliquely at a reflector, then reflects vertically at the mirror surface and reflects again at the same reflector. We are going to fabricate QBI gratings by laminating of mirror plates as similar to fabrication of the QB grating. We will also fabricate silicon and germanium immersion gratings with conventional step-like grooves by means of the latest diamond machining methods. We introduce characteristics and performance of these gratings.

  3. An imaging extreme ultraviolet spectrometer for astrophysical investigations in space

    NASA Technical Reports Server (NTRS)

    Huber, M. C. E.; Timothy, J. G.; Morgan, J. S.; Lemaitre, G.; Tondello, G.

    1986-01-01

    A high-efficiency, extreme ultraviolet (EUV) imaging spectrometer has been constructed and tested. The spectrometer employs a concave toroidal grating illuminated at normal incidence in a Rowland circle mounting and has only one reflecting surface. The toroidal grating has been fabricated by a new technique employing an elastically deformable submaster grating which is replicated in a spherical form and then mechanically distorted to produce the desired aspect ratio of the toroidal surface for stigmatic imaging over the selected wavelength range. The fixed toroidal grating used in the spectrometer is then replicated from this surface. Photographic tests and initial photoelectric tests with a two-dimensional, pulse-counting detector system have verified the image quality of the toroidal grating at wavelengths near 600 A. The basic designs of two instruments employing the spectrometer for astrophysical investigations in space are described, namely, a high-resolution EUV spectroheliometer for studies of the solar chromosphere, transition region, and corona; and an EUV spectroscopic telescope for studies of nonsolar objects.

  4. Ultra-Compact, Superconducting Spectrometer-on-a-Chip at Submillimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Chattopadhyay, Goutam; Zmuidzinas, Jonas; Bradford, Charles M.; Leduc, Henry G.; Day, Peter K.; Swenson, Loren; Hailey-Dunsheath, Steven; O'Brient, Roger C.; Padin, Stephen; Shirokoff, Erik D.; McKenney, Christopher; Reck, Theodore; Siles, Jose V.; Barry, Peter; Doyle, Simon; Mauskopf, Philip; Llombart, Nuria; Kovacs, Attila; Marrone, Dan P.

    2013-01-01

    Small size, wide spectral bandwidth, and highly multiplexed detector readout are required to develop powerful multi-beam spectrometers for high-redshift observations. Currently available spectrometers at these frequencies are large and bulky. The grating sizes for these spectrometers are prohibitive. This fundamental size issue is a key limitation for space-based spectrometers for astrophysics applications. A novel, moderate-resolving-power (R-700), ultra-compact spectrograph-on-a-chip for millimeter and submillimeter wavelengths is the solution.

  5. Spectrometer gun

    DOEpatents

    Waechter, D.A.; Wolf, M.A.; Umbarger, C.J.

    1981-11-03

    A hand-holdable, battery-operated, microprocessor-based spectrometer gun is described that includes a low-power matrix display and sufficient memory to permit both real-time observation and extended analysis of detected radiation pulses. Universality of the incorporated signal processing circuitry permits operation with various detectors having differing pulse detection and sensitivity parameters.

  6. Spectrometer gun

    DOEpatents

    Waechter, David A. (Los Alamos, NM); Wolf, Michael A. (Los Alamos, NM); Umbarger, C. John (Los Alamos, NM)

    1985-01-01

    A hand-holdable, battery-operated, microprocessor-based spectrometer gun includes a low-power matrix display and sufficient memory to permit both real-time observation and extended analysis of detected radiation pulses. Universality of the incorporated signal processing circuitry permits operation with various detectors having differing pulse detection and sensitivity parameters.

  7. HISS spectrometer

    SciTech Connect

    Greiner, D.E.

    1984-11-01

    This talk describes the Heavy Ion Spectrometer System (HISS) facility at the Lawrence Berkeley Laboratory's Bevalac. Three completed experiments and their results are illustrated. The second half of the talk is a detailed discussion of the response of drift chambers to heavy ions. The limitations of trajectory measurement over a large range in incident particle charge are presented.

  8. Long-Wave Infrared Dyson Spectrometer

    NASA Technical Reports Server (NTRS)

    Johnson, William R.; Hook, Simon J.; Mouroulis, Pantazis Z.; Wilson, Daniel W.; Gunapala, Sarath D.; Hill, Cory J.; Mumolo, Jason M.; Eng, Bjorn T.

    2008-01-01

    Preliminary results are presented for an ultra compact long-wave infrared slit spectrometer based on the dyson concentric design. The dyson spectrometer has been integrated in a dewar environment with a quantum well infrared photodetecor (QWIP), concave electron beam fabricated diffraction grating and ultra precision slit. The entire system is cooled to cryogenic temperatures to maximize signal to noise ratio performance, hence eliminating thermal signal from transmissive elements and internal stray light. All of this is done while maintaining QWIP thermal control. A general description is given of the spectrometer, alignment technique and predicated performance. The spectrometer has been designed for optimal performance with respect to smile and keystone distortion. A spectral calibration is performed with NIST traceable targets. A 2-point non-uniformity correction is performed with a precision blackbody source to provide radiometric accuracy. Preliminary laboratory results show excellent agreement with modeled noise equivalent delta temperature and detector linearity over a broad temperature range.

  9. Gratings and waveguides

    NASA Technical Reports Server (NTRS)

    Bates, K. A.; Erwin, J. K.; Li, L.; Burke, J. J.; Ramanujam, N.

    1993-01-01

    Our immediate objective is to understand the limitations of guided-wave and grating coupler devices in their application to optical data storage. Our long-range goal is to develop and validate design codes for integrated optic devices. The principal research activity was in the development of numerical models for the design of a blue wavelength integrated optical source for data storage applications.

  10. Imaging IR spectrometer, phase 2

    NASA Technical Reports Server (NTRS)

    Gradie, Jonathan; Lewis, Ralph; Lundeen, Thomas; Wang, Shu-I

    1990-01-01

    The development is examined of a prototype multi-channel infrared imaging spectrometer. The design, construction and preliminary performance is described. This instrument is intended for use with JPL Table Mountain telescope as well as the 88 inch UH telescope on Mauna Kea. The instrument is capable of sampling simultaneously the spectral region of 0.9 to 2.6 um at an average spectral resolution of 1 percent using a cooled (77 K) optical bench, a concave holographic grating and a special order sorting filter to allow the acquisition of the full spectral range on a 128 x 128 HgCdTe infrared detector array. The field of view of the spectrometer is 0.5 arcsec/pixel in mapping mode and designed to be 5 arcsec/pixel in spot mode. The innovative optical design has resulted in a small, transportable spectrometer, capable of remote operation. Commercial applications of this spectrometer design include remote sensing from both space and aircraft platforms as well as groundbased astronomical observations.

  11. Pupil aberrations in Offner spectrometers.

    PubMed

    Gonzlez-Nez, Hctor; Prieto-Blanco, Xess; de la Fuente, Ral

    2012-04-01

    The light path function (LPF) of an Offner spectrometer is presented. The evaluation of the LPF of this spectrometer enables its imaging properties to be studied for arbitrary object and image positions, while avoiding the more complicated analysis of intermediate images generated by the diffraction grating, which is often involved. A power series expansion of the LPF on the grating coordinates directly determines pupil aberrations of the generated spectrum and facilitates the search for configurations with small low-order aberrations. This analysis not only confirms the possibility of reducing low-order aberrations in Rowland-type mounts, namely astigmatism and coma, as predicted in previous studies, but also proves that all third-order terms in the series expansion of the aberration function can be canceled at the image of the design point and for the corresponding design wavelength, when the design point is located on a plane orthogonal to the optical axis. Furthermore, fourth-order terms are computed and shown to represent the most relevant contribution to image blurring. Third- and fourth-order aberrations are also evaluated for Rowland mounts with the design point located outside the aforementioned plane. The study described in this manuscript is not restricted to small angles of incidence, and, therefore, it goes beyond Seidel and Buchdahl aberrations. PMID:22472819

  12. Dynamic holographic gratings

    NASA Astrophysics Data System (ADS)

    Birabassov, Rouslan

    2001-10-01

    The work presented in this thesis is divided into two related areas. The first area of research was a study of photoanisotropic materials to record dynamic gratings. The second area was a study of stimulated diffusion backscattering in photorefractive crystals. The two areas are related by the fact that in the two cases we studied dynamic gratings. We studied reversible photochemical mechanisms using dye molecules suspended in polymer hosts that could record dynamic holograms. The self-developing refractive index changes in dye-doped or dye-attached polymer materials, in particularly azo-dye-doped polymer systems make them promising candidates for many applications (because of the large photoinduced birefringence). The mechanism of photoanisotropic recording in azo-dye-doped polymer materials is based on orientationally dependent photoisomerization of dye molecules that may be macroscopically described in terms of photoinduced linear dichroism and linear birefringence. We proposed a technique for the fabrication of thick photosensitized polymer materials for real-time (self- developing) holographic applications. Cross modulation experiments to study the photoinduced dichroism are then described and the discussion of photophysical mechanisms involved is given. We used azo-dye doped polymer materials to record thin and thick holograms (scalar and vector). We theoretically and experimentally demonstrated that one could successfully store (using a linearly and an elliptically polarized beams) and reconstruct an elliptical polarization state of light using photoanisotropic materials, even if a plane polarized reference beam is used for the recording and readout. Using photoanisotropic materials, we demonstrated experimentally and theoretically that macroscopic optical chirality may be generated in such systems with a proper choice of excitation beam polarization state. Linear diffraction gratings, that provide strongly asymmetric diffraction without surface modulation were also created and studied. Asymmetric diffraction may be achieved using blazed gratings. But in our case the spatial phase shift of the refractive index grating relative to the absorption grating is the origin of asymmetric behaviour. Experimental results made with thin mixed phase and absorption gratings in azo-dye-doped polymer films are in agreement with our theoretical results. In the second part of the thesis we analysed the stimulated diffusion backscattering (SDS) in photorefractive crystals based on the advantages of the reflection photorefractive gratings. The material research, which is the most acute direction, was studied. We believe that optimal crystal (its processing procedure and doping density) is still unknown even for visible range. We discussed the general analysis of the stimulated diffusion backscattering. We studied the relevant parameters for the sample, which demonstrated the most interesting stimulated diffusion backscattering response: measurements of gain, reflectivity, response rate, dark conductivity and grating decay. We clarified the principal possibilities to obtain self-phase conjugation at backward SDS in steady-state conditions. We also made the comparison of sensitivities of different geometries with respect to pump energy. Finally, we experimentally studied double-phase-conjugation geometry at double-loop reflection gratings.

  13. Pushing the Boundaries of X-ray Grating Spectroscopy in a Suborbital Rocket

    NASA Technical Reports Server (NTRS)

    McEntaffer, Randall L.; DeRoo, Casey; Schultz, Ted; Zhang, William W.; Murray, Neil J.; O'Dell, Stephen; Cash, Webster

    2013-01-01

    Developments in grating spectroscopy are paramount for meeting the soft X-ray science goals of future NASA X-ray Observatories. While developments in the laboratory setting have verified the technical feasibility of using off-plane reflection gratings to reach this goal, flight heritage is a key step in the development process toward large missions. To this end we have developed a design for a suborbital rocket payload employing an Off-Plane X-ray Grating Spectrometer. This spectrometer utilizes slumped glass Wolter-1 optics, an array of gratings, and a CCD camera. We discuss the unique capabilities of this design, the expected performance, the science return, and the perceived impact to future missions.

  14. Scanning imaging absorption spectrometer for atmospheric chartography

    NASA Technical Reports Server (NTRS)

    Burrows, John P.; Chance, Kelly V.

    1991-01-01

    The SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY is an instrument which measures backscattered, reflected, and transmitted light from the earth's atmosphere and surface. SCIAMACHY has eight spectral channels which observe simultaneously the spectral region between 240 and 1700 nm and selected windows between 1940 and 2400 nm. Each spectral channel contains a grating and linear diode array detector. SCIAMACHY observes the atmosphere in nadir, limb, and solar and lunar occultation viewing geometries.

  15. Calibration of a High Resolution Soft X-ray Spectrometer

    SciTech Connect

    Dunn, J; Beiersdorfer, P; Brown, G V; Magee, E W

    2010-01-26

    A high resolution grating spectrometer (HRGS) with 2400 line/mm variable line spacing grating for the 10-50 {angstrom} wavelength range has been designed for laser-produced plasma experiments at the Lawrence Livermore National Laboratory (LLNL). The spectrometer has a large radius of curvature, R=44.3 m, is operated at a 2{sup o} grazing angle and can record high signal-to-noise spectra when used with a low-noise, cooled, charge-coupled device detector. The instrument can be operated with a 10-25 {micro}m wide slit to achieve the best spectral resolving power on laser plasma sources, approaching 2000, or in slitless mode with a small symmetrical emission source. Results will be presented for the spectral response of the spectrometer cross-calibrated at the LLNL Electron Beam Ion Trap facility using the broadband x-ray energy EBIT Calorimeter Spectrometer (ECS).

  16. Field imaging far-infrared line spectrometer FIFI LS

    NASA Astrophysics Data System (ADS)

    Raab, Walfried; Geis, Norbert; Looney, Leslie W.; Poglitsch, Albrecht; Rosenthal, Dirk; Urban, Alexander; Henning, Thomas; Beeman, Jeffrey W.

    1999-12-01

    We present our design for a field-imaging, far-infrared line spectrometer for the SOFIA airborne observatory. The instrument will employ two parallel, medium resolution (R approximately 1700) grating spectrometers for simultaneous observations in the wavelength bands 42 - 110 micrometer and 110 - 210 micrometer. The Littrov mounted gratings are operated in first and second order. Large stressed and unstressed 16 X 25 pixel Ge:Ga photoconductor arrays are operated in the spectrometer channel, providing good spectral coverage with high responsivity. Image slicers in each spectrometer branch redistribute the 5 X 5 pixel field of view along the 1 X 25 pixel entrance slits of the spectrographs, providing both, spatial and spectral multiplexing. Thus, for each of the 25 spatial pixels, we are able to cover a velocity range of approximately 1500 km/s around a selected far infrared line, with an estimated sensitivity of approximately 2 X 10-15 W Hz-1/2 per pixel.

  17. Research on design method of spaceborne imaging spectrometer system based on telecentric optical system

    NASA Astrophysics Data System (ADS)

    Liu, Xiaomei; Liu, Hua

    2015-08-01

    Imaging spectrometer is widely applied in the field of space remote sensing. Dispersion imaging spectrometer with prism or grating is developed rapidly and used widely. It is developed to the direction of high performance and miniaturization, such as large field of view, high resolution, small volume, etc. For meeting the demand of the development, by comparing the characteristics and the situation of development and application about the two kinds of spectrometer, based on the imaging theory of telecentric optical system, the article studied a design method of prism dispersion imaging spectrometer with telecentric Off-axis Three-Mirror imaging system. The instrument designed by using this method has smaller volume and weight than traditional instrument. It overcomes the biggest defect that traditional prism dispersion imaging spectrometer is bigger, increases its advantages in actual use in contrast to grating dispersion imaging spectrometer, and promotes the development and application of prism dispersion imaging spectrometer.

  18. Optical design of a coastal ocean imaging spectrometer.

    TOXLINE Toxicology Bibliographic Information

    Mouroulis P; Green RO; Wilson DW

    2008-06-09

    We present an optical design for an airborne imaging spectrometer that addresses the unique constraints imposed by imaging the coastal ocean region. A fast (F/1.8) wide field system (36 degrees) with minimum polarization dependence and high response uniformity is required, that covers the spectral range 350-1050 nm with 3 nm sampling. We show how these requirements can be achieved with a two-mirror telescope and a compact Dyson spectrometer utilizing a polarization-insensitive diffraction grating.

  19. Research directed toward improved echelles for the ultraviolet. [large space teslescope spectrographs

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Low frequency gratings obtainable with present technology, can meet the grating-efficiency design goals for potential space telescope spectrographs. Gratings made with changes in the three specific parameters: the ruling tool profile, the coating material, and the lubricants used during the ruling process were compared. A series of coatings and test gratings were fabricated and were examined for surface smoothness with a Nomarski differential interference microscope and an electron microsocope. Photomicrographs were obtained to show the difference in smoothness of the various coatings and rulings. Efficiency measurements were made for those test rulings that showed good groove characteristics: smoothness, proper ruling depth, and absence of defects (e.g., streaks, feathered edges and rough sides). Higher grating efficiency should be correlated with the degree of smoothness of both the coating and the grating groove.

  20. Review of multilayer normal-incidence gratings operating at 9- to 40-nm wavelengths

    NASA Astrophysics Data System (ADS)

    Seely, John F.

    2002-12-01

    It is now possible to reliably implement multilayer-coated diffraction gratings in spaceflight and laboratory spectrometers that operate at normal incidence and with high efficiency in the 9 nm to 40 nm wavelength range. The design and fabrication of the grating groove profile and the matching multilayer coating are based on computational modeling using the computer program PCGRATE. The multilayer gratings are characterized using atomic force microscopy and by measuring the diffraction efficiency using synchrotron radiation. Recent research has focused on multilayer coatings other than Mo/Si such as Sc/Si for 40 nm, MoRu/Be for 11 nm, and Mo/Y for 9 nm.

  1. The evaluation of a deformable diffraction grating for a stigmatic EUV spectroheliometer

    NASA Astrophysics Data System (ADS)

    Timothy, J. G.

    1987-11-01

    A high-efficiency, extreme ultraviolet (EUV) imaging spectrometer is constructed and tested. The spectrometer employs a concave toroidal grating illuminated at normal incidence in a Rowland circle mounting and has only one reflecting surface. The toroidal grating has been fabricated by a new technique employing an elastically-deformable sub-master grating replicated in a spherical form and then mechanically distorted to produce the desired aspect ratio of the toroidal surface for stigmatic imaging over the selected wavelength range. The fixed toroidal grating used in the spectrometer is then replicated from this surface. Photographic tests and initial photoelectric tests with a two-dimensional, pulse-counting detector system verify the image quality of the toroidal grating at wavelengths near 600 A. The results of these tests and the basic designs of two instruments which could employ the imaging spectrometer for astrophysical investigations in space are described; i.e., a high-resolution EUV spectroheliometer for studies of the solar chromosphere, transition region, and corona; and an EUV spectroscopic telescope for studies of non-solar objects.

  2. The evaluation of a deformable diffraction grating for a stigmatic EUV spectroheliometer

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1987-01-01

    A high-efficiency, extreme ultraviolet (EUV) imaging spectrometer is constructed and tested. The spectrometer employs a concave toroidal grating illuminated at normal incidence in a Rowland circle mounting and has only one reflecting surface. The toroidal grating has been fabricated by a new technique employing an elastically-deformable sub-master grating replicated in a spherical form and then mechanically distorted to produce the desired aspect ratio of the toroidal surface for stigmatic imaging over the selected wavelength range. The fixed toroidal grating used in the spectrometer is then replicated from this surface. Photographic tests and initial photoelectric tests with a two-dimensional, pulse-counting detector system verify the image quality of the toroidal grating at wavelengths near 600 A. The results of these tests and the basic designs of two instruments which could employ the imaging spectrometer for astrophysical investigations in space are described; i.e., a high-resolution EUV spectroheliometer for studies of the solar chromosphere, transition region, and corona; and an EUV spectroscopic telescope for studies of non-solar objects.

  3. Charged particle accelerator grating

    DOEpatents

    Palmer, R.B.

    1985-09-09

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  4. Development of lightweight blazed transmission gratings and large-area soft x-ray spectrographs

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Bruccoleri, Alex R.; Guan, Dong; Schattenburg, Mark L.

    2013-09-01

    Large area, high resolving power spectroscopy in the soft x-ray band can only be achieved with a state-of-the-art diffraction grating spectrometer, comprised of large collecting-area focusing optics with a narrow point spread function, large-area high-resolving power diffraction gratings, and small pixel, order sorting x-ray detectors. Recently developed critical-angle transmission (CAT) gratings combine the advantages of transmission gratings (low mass, relaxed figure and alignment tolerances) and blazed reflection gratings (high broad band diffraction efficiency, utilization of higher diffraction orders). Several new mission concepts containing CAT grating based spectrometers (AEGIS, AXSIO, SMART-X) promise to deliver unprecedented order-of-magnitude improvements in soft x-ray spectroscopy figures of merit related to the detection and characterization of emission and absorption lines, thereby addressing high-priority questions identified in the Astro2010 Decadal Survey "New Worlds New Horizons". We review the current status of CAT grating fabrication, present recent fabrication results, and describe our plans and technology development roadmap for the coming year and beyond.

  5. High-efficiency blazed transmission gratings for high-resolution soft x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Bruccoleri, Alexander R.; Schattenburg, Mark L.

    2015-01-01

    High-resolution spectroscopy of astrophysical sources is the key to gaining a quantitative understanding of the history, dynamics, and current conditions of the cosmos. A large-area (> 1,000 cm2), high resolving power (R = ?/?? > 3,000) soft x-ray spectrometer that covers the lines of C, N, O, Ne and Fe ions is the ideal tool to address a number of high-priority sciences questions from the 2010 Decadal Survey, such as the connection between super-massive black holes and large-scale structure via cosmic feedback, the evolution of large-scale structure, the behavior of matter at high densities, and the conditions close to black holes. Numerous mission concepts that meet these requirements have been studied and proposed over the last few years, including grating instruments for the International X-ray Observatory. Nevertheless, no grating missions are currently approved. To improve the chances for future soft x-ray grating spectroscopy missions, grating technology has to progress and be advanced to higher TRLs. We have developed Critical-Angle Transmission (CAT) gratings that combine the advantages of blazed reflection gratings (high efficiency, use of higher diffraction orders) with those of conventional transmission gratings (low mass, relaxed alignment tolerances and temperature requirements, transparent at higher energies). A CAT grating-based spectrometer can provide performance 1-2 orders of magnitude better than current grating instruments on Chandra and Newton-XMM with minimal resource requirements. We have fabricated large-area free-standing CAT gratings with minimal integrated support structures from silicon-on-insulator wafers using advanced lithography and a combination of deep reactive-ion and wet etching, and will present our latest x-ray test results showing record high diffraction efficiencies in blazed orders.

  6. High-efficiency blazed transmission gratings for high-resolution soft x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Bruccoleri, Alexander R.; Schattenburg, Mark L.

    2015-09-01

    High-resolution spectroscopy of astrophysical sources is the key to gaining a quantitative understanding of the history, dynamics, and current conditions of the cosmos. A large-area (> 1,000 cm2), high resolving power (R = λ/Δλ> 3000) soft x-ray grating spectrometer (XGS) that covers the lines of C, N, O, Ne and Fe ions is the ideal tool to address a number of high-priority science questions from the 2010 Decadal Survey, such as the connection between super-massive black holes and large-scale structure via cosmic feedback, the evolution of large- scale structure, the behavior of matter at high densities, and the conditions close to black holes. While no grating missions or instruments are currently approved, an XGS aboard a potential future X-ray Surveyor could easily surpass the above performance metrics. To improve the chances for future soft x-ray grating spectroscopy missions or instruments, grating technology has to progress and advance to higher Technology Readiness Levels (TRLs). To that end we have developed Critical-Angle Transmission (CAT) gratings that combine the advantages of blazed reflection gratings (high efficiency, use of higher diffraction orders) with those of conventional transmission gratings (low mass, relaxed alignment tolerances and temperature requirements, high transparency at higher energies). A CAT grating-based spectrometer can provide performance 1-2 orders of magnitude better than current grating instruments on Chandra and Newton-XMM with minimal resource requirements. At present we have fabricated large-area freestanding CAT gratings with narrow integrated support structures from silicon-on- insulator wafers using advanced lithography and a combination of deep reactive-ion and wet etching. Our latest x-ray test results show record high absolute diffraction efficiencies in blazed orders in excess of 30% with room for improvement.

  7. Fabrication of large-area and low mass critical-angle x-ray transmission gratings

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Bruccoleri, Alex R.; Guan, Dong; Schattenburg, Mark L.

    2014-07-01

    Soft x-ray spectroscopy of celestial sources with high resolving power R = E/?E and large collecting area addresses important science listed in the Astro2010 Decadal Survey New Worlds New Horizons, such as the growth of the large scale structure of the universe and its interaction with active galactic nuclei, the kinematics of galactic outflows, as well as coronal emission from stars and other topics. Numerous studies have shown that a transmission grating spectrometer based on lightweight critical-angle transmission (CAT) gratings can deliver R = 3000-5000 and large collecting area with high efficiency and minimal resource requirements, providing spectroscopic figures of merit at least an order of magnitude better than grating spectrometers on Chandra and XMM-Newton, as well as future calorimeter-based missions. The recently developed CAT gratings combine the advantages of transmission gratings (low mass, relaxed figure and alignment tolerances) and blazed reflection gratings (high broad band diffraction efficiency, utilization of higher diffraction orders). Their working principle based on blazing through reflection off the smooth, ultra-high aspect ratio grating bar sidewalls has previously been demonstrated on small samples with x rays. For larger gratings (area greater than 1 inch square) we developed a fabrication process for grating membranes with a hierarchy of integrated low-obscuration supports. The fabrication involves a combination of advanced lithography and highly anisotropic dry and wet etching techniques. We report on the latest fabrication results of free-standing, large-area CAT gratings with polished sidewalls and preliminary x-ray tests.

  8. Extreme ultraviolet spectrometer for the Shenguang III laser facility.

    PubMed

    Xiong, Gang; Yang, Guohong; Zhang, Jiyan; Wei, Minxi; Zhao, Yang; Qing, Bo; Lv, Min; Yang, Zhenghua; Wang, Feng; Liu, Shenye; Cai, Houzhi; Liu, Jinyuan

    2015-06-10

    An extreme ultraviolet spectrometer has been developed for high-energy density physics experiments at the Shenguang-III (SG-III) laser facility. Alternative use of two different varied-line-spacing gratings covers a wavelength range of 10-260 . A newly developed x-ray framing camera with single wide strip line is designed to record time-gated spectra with ~70 ps temporal resolution and 20 lp/mm spatial resolution. The width of the strip line is up to 20 mm, enhancing the capability of the spatial resolving measurements. All components of the x-ray framing camera are roomed in an aluminum air box. The whole spectrometer is mounted on a diagnostic instrument manipulator at the SG-III laser facility for the first time. A new alignment method for the spectrometer based on the superimposition of two laser focal spots is developed. The approaches of the alignment including offline and online two steps are described. A carbon spectrum and an aluminum spectrum have been successfully recorded by the spectrometer using 2400 l/mm and 1200 l/mm gratings, respectively. The experimental spectral lines show that the spectral resolution of the spectrometer is about 0.2 and 1 for the 2400 l/mm and 1200 l/mm gratings, respectively. A theoretical calculation was carried out to estimate the maximum resolving power of the spectrometer. PMID:26192833

  9. Progress in the development of critical-angle transmission gratings

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Bruccoleri, Alex R.; Mukherjee, Pran; Schattenburg, Mark L.

    2012-09-01

    Recently developed Critical-Angle Transmission (CAT) grating technology - in combination with x-ray CCD cameras and large collecting-area focusing optics - will enable a new generation of soft x-ray spectrometers with unprecedented resolving power and effective area and with at least an order of magnitude improvement in figures-of-merit for emission and absorption line detection. This technology will be essential to address a number of high-priority questions identified in the Astro2010 Decadal Survey New Worlds New Horizons and open the door to a new discovery space. CAT gratings combine the advantages of soft x-ray transmission gratings (low mass, relaxed figure and alignment tolerances, transparent at high energies) and blazed reflection gratings (high broad band diffraction efficiency, utilization of higher diffraction orders to increase resolving power). We report on progress in the fabrication of large-area (31 31 mm2) free-standing gratings with two levels of low-blockage support structures using highly anisotropic deep reactive-ion etching.

  10. High Efficiency Binary Blazed Grating Waveguide Couplers

    NASA Technical Reports Server (NTRS)

    Watson, Michael D.; Abushagur, Mustafa A. G.; Ashley, Paul R.; Cole, Helen

    1998-01-01

    Binary blazed gratings are investigated as highly efficient waveguide couplers. Equations are derived for the design of efficient binary blazed grating waveguide couplers. The design approach relates waveguide blazed grating equations to Artificial Index Grating (AIG) equations to emulate a blazed grating. Using these relationships, binary blazed gratings can be accurately designed to output a single mode at a desired output angle. Binary blazed grating couplers can achieve single mode cladding output without substrate" radiation output modes. Much higher output angles can be achieved than with rectangular grating couplers. The use of the AIG grating structure simplifies fabrication approaches. Waveguide couplers were designed using these equations.

  11. Super-smooth x-ray reflection grating fabrication

    SciTech Connect

    Franke, A.E.; Schattenburg, M.L.; Gullikson, E.M.; Cottam, J.; Kahn, S.M.; Rasmussen, A.

    1997-11-01

    Blazed, grazing incidence x-ray reflection gratings are an important component of modern high resolution spectrometers and related x-ray optics. These have traditionally been fabricated by diamond scribing in a ruling engine, or more recently by interferometric lithography followed by ion etching. These traditional methods result in gratings which suffer from a number of deficiencies, including high surface roughness and poor control of the groove profile. These deficiencies lead to poor diffraction efficiency and high levels of scattered light. We have developed a novel fabrication method for fabricating blazed x-ray reflection gratings which utilizes silicon wafers that are cut 0.7{degree} off of the (111) plane. In solutions such as potassium hydroxide (KOH), silicon is etched in {l_angle}111{r_angle} directions orders of magnitude slower than in other directions, resulting in extremely smooth {l_brace}111{r_brace} facets. The gratings are patterned using interferometric lithography with 351.1 nm wavelength and transferred into the substrate using tri-level resist processing, reactive-ion etching (RIE), and silicon nitride masking during the KOH etch. The narrow ({lt}0.1{mu}m) ridge of silicon which supports the nitride mask is removed using a chromium lift-off step followed by a CF{sub 4} RIE trench etch. The result is a grating with extremely smooth blaze facets which is suitable for x-ray reflection after evaporative coating with thin Cr/Au. Atomic force microscope images confirm that fabricated gratings have less than a 0.4 nm rms roughness{emdash}much smoother than conventional gratings which have over {approximately}1nm roughness. Theory predicts that reduced blaze facet roughness increases diffraction efficiency. Experiments and simulations performed at the Lawrence Berkeley Laboratory and Columbia University confirm that efficiency is increased; in fact, measured peak efficiencies reach {approximately}80{percent} of calculated theoretical limits. (Abstract Truncated)

  12. Performance of silicon immersed gratings: measurement, analysis, and modeling

    NASA Astrophysics Data System (ADS)

    Rodenhuis, Michiel; Tol, Paul J. J.; Coppens, Tonny H. M.; Laubert, Phillip P.; van Amerongen, Aaldert H.

    2015-09-01

    The use of Immersed Gratings offers advantages for both space- and ground-based spectrographs. As diffraction takes place inside the high-index medium, the optical path difference and angular dispersion are boosted proportionally, thereby allowing a smaller grating area and a smaller spectrometer size. Short-wave infrared (SWIR) spectroscopy is used in space-based monitoring of greenhouse and pollution gases in the Earth atmosphere. On the extremely large telescopes currently under development, mid-infrared high-resolution spectrographs will, among other things, be used to characterize exo-planet atmospheres. At infrared wavelengths, Silicon is transparent. This means that production methods used in the semiconductor industry can be applied to the fabrication of immersed gratings. Using such methods, we have designed and built immersed gratings for both space- and ground-based instruments, examples being the TROPOMI instrument for the European Space Agency Sentinel-5 precursor mission, Sentinel-5 (ESA) and the METIS (Mid-infrared E-ELT Imager and Spectrograph) instrument for the European Extremely Large Telescope. Three key parameters govern the performance of such gratings: The efficiency, the level of scattered light and the wavefront error induced. In this paper we describe how we can optimize these parameters during the design and manufacturing phase. We focus on the tools and methods used to measure the actual performance realized and present the results. In this paper, the bread-board model (BBM) immersed grating developed for the SWIR-1 channel of Sentinel-5 is used to illustrate this process. Stringent requirements were specified for this grating for the three performance criteria. We will show that -with some margin- the performance requirements have all been met.

  13. Designing an acousto-optical spectrometer for Guillermo Haro Astrophysical Observatory

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Arellanes Bernabe, Adan Omar; Chavushyan, Vahram

    2013-09-01

    The Guillermo Haro astrophysical observatory (Mexico) realizes investigations in the visible and near-infrared range . Actually, the classical grating spectrometer with mechanically removable optical filters and diffraction gratings is exploited there. Unfortunately, the regular process of changing the diffraction gratings with different resolutions and recalibrating the spectrometer is inconvenient and wastes expensive time for observations. This is why exploiting an acousto-optical cell as a dynamic dispersive element is practically desirable, because potentially it realizes tuning the spectral resolution and the range of observation electronically and excludes filters. Some aspects of inserting just one dynamic acousto-optical diffraction grating instead of a set of the traditional static diffraction gratings are preliminarily considered.

  14. Grating-structured metallic microsprings.

    PubMed

    Huang, Tao; Liu, Zhaoqian; Huang, Gaoshan; Liu, Ran; Mei, Yongfeng

    2014-08-21

    We fabricate grating-structured metallic microsprings with well-defined helical angles and diameters, which are self-rolled from strained nanomembranes patterned with gratings. The grating structures on the metal membrane, replicated from the imprinted polymer layer beneath, give rise to the controlled rolling direction after selective etching of the underlying sacrificial layer. The rolling direction of the grating-structured thin metal film is always perpendicular to the long side edge of gratings, offering a good way to roll up strained strips into well controlled three-dimensional (3D) microsprings simply by altering the dimension and orientation of the structured strips. The mechanical elasticity of these grating-structured metallic microsprings is verified for the potential application as a flow rate sensor. Our work may stimulate rigorous synthesis of highly functional and complex 3D helical micro and nanostructures, and hint a broad range of applications such as environmental sensors, micro-/nanoscale robots, metamaterials, etc. PMID:24728100

  15. Fiber Bragg grating microphone system

    NASA Astrophysics Data System (ADS)

    Mohanty, Lipi; Koh, Liang Mong; Tjin, Swee Chuan

    2006-10-01

    A fiber Bragg grating microphone has been developed and tested in the audible frequency range. The fiber Bragg grating is longitudinally attached to a membrane that vibrates in response to acoustic vibrations and is prestrained. The frequency and amplitude of the sound are encoded in the wavelength shift. The microphone can also pick up voices dynamically from a distance of a few meters. The simplicity of principle and structure of this fiber grating sensor provides scope for commercialization as an optical microphone.

  16. Developing Tools for Undergraduate Spectroscopy: An Inexpensive Visible Light Spectrometer

    ERIC Educational Resources Information Center

    Vanderveen, Jesse R.; Martin, Brian; Ooms, Kristopher J.

    2013-01-01

    The design and implementation of an inexpensive, high-resolution Littrow-type visible light spectrometer is presented. The instrument is built from low-cost materials and interfaced with the program RSpec for real-time spectral analysis, making it useful for classroom and laboratory exercises. Using a diffraction grating ruled at 1200 lines/mm and

  17. Optical system for high resolution spectrometer/monochromator

    DOEpatents

    Hettrick, Michael C. (Berkeley, CA); Underwood, James H. (Walnut Creek, CA)

    1988-01-01

    An optical system for use in a spectrometer or monochromator employing a mirror which reflects electromagnetic radiation from a source to converge with same in a plane. A straight grooved, varied-spaced diffraction grating receives the converging electromagnetic radiation from the mirror and produces a spectral image for capture by a detector, target or like receiver.

  18. Optical system for high resolution spectrometer/monochromator

    DOEpatents

    Hettrick, M.C.; Underwood, J.H.

    1988-10-11

    An optical system for use in a spectrometer or monochromator employing a mirror which reflects electromagnetic radiation from a source to converge with same in a plane is disclosed. A straight grooved, varied-spaced diffraction grating receives the converging electromagnetic radiation from the mirror and produces a spectral image for capture by a detector, target or like receiver. 11 figs.

  19. Developing Tools for Undergraduate Spectroscopy: An Inexpensive Visible Light Spectrometer

    ERIC Educational Resources Information Center

    Vanderveen, Jesse R.; Martin, Brian; Ooms, Kristopher J.

    2013-01-01

    The design and implementation of an inexpensive, high-resolution Littrow-type visible light spectrometer is presented. The instrument is built from low-cost materials and interfaced with the program RSpec for real-time spectral analysis, making it useful for classroom and laboratory exercises. Using a diffraction grating ruled at 1200 lines/mm and…

  20. High accuracy wavelength calibration for a scanning visible spectrometer

    SciTech Connect

    Scotti, Filippo; Bell, Ronald E.

    2010-10-15

    Spectroscopic applications for plasma velocity measurements often require wavelength accuracies {<=}0.2 A. An automated calibration, which is stable over time and environmental conditions without the need to recalibrate after each grating movement, was developed for a scanning spectrometer to achieve high wavelength accuracy over the visible spectrum. This method fits all relevant spectrometer parameters using multiple calibration spectra. With a stepping-motor controlled sine drive, an accuracy of {approx}0.25 A has been demonstrated. With the addition of a high resolution (0.075 arc sec) optical encoder on the grating stage, greater precision ({approx}0.005 A) is possible, allowing absolute velocity measurements within {approx}0.3 km/s. This level of precision requires monitoring of atmospheric temperature and pressure and of grating bulk temperature to correct for changes in the refractive index of air and the groove density, respectively.

  1. Degradation Free Spectrometers for Solar EUV Measurements

    NASA Astrophysics Data System (ADS)

    Wieman, S. R.; Didkovsky, L. V.; Judge, D. L.; McMullin, D. R.

    2011-12-01

    Solar EUV observations will be made using two new degradation-free EUV spectrometers on a sounding rocket flight scheduled for summer 2012. The two instruments, a rare gas photoionization-based Optics-Free Spectrometer (OFS) and a Dual Grating Spectrometer (DGS), are filter-free and optics-free. OFS can measure the solar EUV spectrum with a spectral resolution comparable to that of grating-based EUV spectrometers. The DGS selectable spectral bandwidth is designed to provide solar irradiance in a 10 nm band centered on the Lyman-alpha 121.6 nm line and a 4 nm band centered on the He-II 30.4 nm line to overlap EUV observations from the SDO/EUV Variability Experiment (EVE) and the SOHO/Solar EUV Monitor (SEM). A clone of the SOHO/SEM flight instrument and a Rare Gas Ionization Cell (RGIC) absolute EUV detector will also be flown to provide additional measurements for inter-comparison. Program delays related to the sounding rocket flight termination system, which was no longer approved by the White Sands Missile Range prevented the previously scheduled summer 2011 launch of these instruments. During this delay several enhancements have been made to the sounding rocket versions of the DFS instruments, including a lighter, simplified vacuum housing and gas system for the OFS and an improved mounting for the DGS, which allows more accurate co-alignment of the optical axes of the DGS, OFS, and the SOHO/SEM clone. Details of these enhancements and results from additional lab testing of the instruments are reported here. The spectrometers are being developed and demonstrated as part of the Degradation Free Spectrometers (DFS) project under NASA's Low Cost Access to Space (LCAS) program and are supported by NASA Grant NNX08BA12G.

  2. Elliptical varied line-space (EVLS) gratings

    NASA Astrophysics Data System (ADS)

    Thomas, Roger J.

    2004-10-01

    Imaging spectroscopy at wavelengths below 2000 Å offers an especially powerful method for studying many extended high-temperature astronomical objects, like the Sun and its outer layers. But the technology to make such measurements is also especially challenging, because of the poor reflectance of all standard materials at these wavelengths, and because the observation must be made from above the absorbing effects of the Earth's atmosphere. To solve these problems, single-reflection stigmatic spectrographs for XUV wavelengths have bee flown on several space missions based on designs with toroidal uniform line-space (TULS) or spherical varied line-space (SVLS) gratings that operate at near normal-incidence. More recently, three solar EUV/UV instruments have been selected that use toroidal varied line-space (TVLS) gratings; these are SUMI and RAISE, both sounding rocket payloads, and NEXUS, a SMEX satellite-mission. The next logical extension to such designs is the use of elliptical surfaces for varied line-space (EVLS) rulings. In fact, EVLS designs are found to provide superior imaging even at very large spectrograph magnifications and beam-speeds, permitting extremely high-quality performance in remarkably compact instrument packages. In some cases, such designs may be optimized even further by using a hyperbolic surface for the feeding telescope. The optical characteristics of two solar EUV spectrometers based on these concepts are described: EUS and EUI, both being developed as possible instruments for ESA's Solar Orbiter mission by consortia led by RAL and by MSSL, respectively.

  3. Electronically Tunable Grating-Gate Terahertz Detectors

    NASA Astrophysics Data System (ADS)

    Shaner, E. A.; Wanke, M. C.; Lee, Mark; Grine, A. D.; Reno, J. L.; Allen, S. J.

    2007-03-01

    Spectroscopy in the millimeter-wave to THz frequencies has received a great deal of recent interest for security applications and chemical identification. This talk will address detectors that utilize plasmons in high-mobility GaAs/AlGaAs quantum well structures to provide a frequency tunable detector response. In particular, recent advances on the grating-gate detector, including membrane and split-gate versions, will be presented. The discussion will include our understanding of the detection mechanisms involved as well as the noise equivalent powers that have been achieved in the various geometries. Currently, the grating-gate style of detector covers a frequency range from 150GHz to 1THz at temperatures ranging from 4K to 80K, however, the ultimate frequency and temperature limits of these detectors are not currently known. The ability to tune the detector response by simply changing a gate voltage leads to an attractive `spectrometer-on-a-chip' where no moving parts would be needed for THz spectral analysis. To date we have achieved spectral scans from 600GHz to 1THz in 12.5ms with a measured 15GHz minimum linewidth. *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  4. Fibre gratings and their applications

    SciTech Connect

    Vasil'ev, Sergei A; Medvedkov, O I; Korolev, I G; Bozhkov, A S; Kurkov, Andrei S; Dianov, Evgenii M

    2005-12-31

    A brief review is given of the state of the art in the research on the photosensitivity of fibres and photoinduced fibre gratings. The most important properties of fibre gratings are considered and the main methods of their production and their applications are discussed. The photosensitive compositions of silica glasses are presented and methods for increasing their photosensitivity are indicated. (review)

  5. Spectrometer Technology Development for Far-Infrared Line Surveys

    NASA Technical Reports Server (NTRS)

    Glenn, Jason

    2005-01-01

    The objective of this proposal was to build and demonstrate a new direct-detection diffraction grating concept and couple it to an array of bolometers. The spectrometer was to be built around a parallel-plate waveguide diffraction grating, WaFIRS: Waveguide Far-InfraRed Spectrometer. The grating is two dimensional in nature, which provides a compact configuration to suit NASA s needs for cryogenic spectrometers for future opportunities, such as infrared/submillimeter spectrometers for a suborbital balloon platform, for SOFIA, for SPICA (a Japanese satellite), and for SAFIR. Our goal was to build a spectrometer (Z-Spec) for 1.0 - 1.5 mm and demonstrate spectral resolution, throughput, and background-limited performance. This grant would partially cover the expenses and we were subsequently awarded a second grant, NAGS-12788, to complete the project. We have one-year received a no-cost extension on NAG.5-12788, to be completed in 3/31/06.

  6. Phononic crystal diffraction gratings

    NASA Astrophysics Data System (ADS)

    Moiseyenko, Rayisa P.; Herbison, Sarah; Declercq, Nico F.; Laude, Vincent

    2012-02-01

    When a phononic crystal is interrogated by an external source of acoustic waves, there is necessarily a phenomenon of diffraction occurring on the external enclosing surfaces. Indeed, these external surfaces are periodic and the resulting acoustic diffraction grating has a periodicity that depends on the orientation of the phononic crystal. This work presents a combined experimental and theoretical study on the diffraction of bulk ultrasonic waves on the external surfaces of a 2D phononic crystal that consists of a triangular lattice of steel rods in a water matrix. The results of transmission experiments are compared with theoretical band structures obtained with the finite-element method. Angular spectrograms (showing frequency as a function of angle) determined from diffraction experiments are then compared with finite-element simulations of diffraction occurring on the surfaces of the crystal. The experimental results show that the diffraction that occurs on its external surfaces is highly frequency-dependent and has a definite relation with the Bloch modes of the phononic crystal. In particular, a strong influence of the presence of bandgaps and deaf bands on the diffraction efficiency is found. This observation opens perspectives for the design of efficient phononic crystal diffraction gratings.

  7. Development in replicated nickel gratings

    NASA Astrophysics Data System (ADS)

    McKinney, W. R.; Bartle, L. G.

    1982-05-01

    Fabrication characteristics and test results with replicated nickel gratings as cleanable, recoatable, bakeable, inexpensive, thermally conductive, high-energy, laser pulse-resistant devices for lasers, and monochromators for synchrotron applications are reviewed. The replicated form of the grating was chosen as a compromise between solid nickel and epoxy gratings. Stress is eliminated in the electroforming process by stopping the process when the nickel is 120 mm thick. An epoxy cast is used for the nickel electroform. Test results with a 1200 g/mm grating blazed in the visible region and a 3600 g/mm grating blazed in the far-UV are presented. Trade-offs were found to be necessary between a good optical figure and peel strength. Resistance to 7-10 J/sq cm laser pulses has been demonstrated.

  8. Test of prototype ITER vacuum ultraviolet spectrometer and its application to impurity study in KSTAR plasmas.

    PubMed

    Seon, C R; Hong, J H; Jang, J; Lee, S H; Choe, W; Lee, H H; Cheon, M S; Pak, S; Lee, H G; Biel, W; Barnsley, R

    2014-11-01

    To optimize the design of ITER vacuum ultraviolet (VUV) spectrometer, a prototype VUV spectrometer was developed. The sensitivity calibration curve of the spectrometer was calculated from the mirror reflectivity, the grating efficiency, and the detector efficiency. The calibration curve was consistent with the calibration points derived in the experiment using the calibrated hollow cathode lamp. For the application of the prototype ITER VUV spectrometer, the prototype spectrometer was installed at KSTAR, and various impurity emission lines could be measured. By analyzing about 100 shots, strong positive correlation between the O VI and the C IV emission intensities could be found. PMID:25430310

  9. AXAF CCD Imaging Spectrometer (ACIS)

    NASA Astrophysics Data System (ADS)

    Garmire, G. P.

    1997-05-01

    The ACIS is an advanced X-ray camera for the AXAF scheduled to be launched in 1998. The camera is composed of two arrays of CCDs, one optimized for imaging using four CCDs abutted in a square array, and a linear array of six CCDs optimized for imaging the dispersed spectrum formed by the High and Medium Energy Transmission Grating Spectrometers. The imaging array is tipped with respect to the optical axis to better approximate the curved focal surface formed by the AXAF Wolter Type I optics. The spectroscopic array has a slight tilt to follow the Rowland circle of the grating focus. The CCD camera and electronics were built at the MIT Center for Space Research and Lincoln Laborator. Much of the thermal and mechanical design as well as the power system were carried out at Lockheed-Martin in Denver, Colorado. The CCDs have been calibrated at MIT and the synchrotron at BESSY in Berlin, Germany. The entire flight instrument has been calibrated at the XRCF facility at Marshall Space flight Center in Huntsville, Alabama. The anticipated instrument performance characteristics based on the calibration reluts will be pre A few examples of possible observations will werve to illustrate the great scientific capabilities of the AXAF.

  10. Normal incidence spectrophotometer using high density transmission grating technology and highly efficiency silicon photodiodes for absolute solar EUV irradiance measurements

    NASA Technical Reports Server (NTRS)

    Ogawa, H. S.; Mcmullin, D.; Judge, D. L.; Korde, R.

    1992-01-01

    New developments in transmission grating and photodiode technology now make it possible to realize spectrometers in the extreme ultraviolet (EUV) spectral region (wavelengths less than 1000 A) which are expected to be virtually constant in their diffraction and detector properties. Time dependent effects associated with reflection gratings are eliminated through the use of free standing transmission gratings. These gratings together with recently developed and highly stable EUV photodiodes have been utilized to construct a highly stable normal incidence spectrophotometer to monitor the variability and absolute intensity of the solar 304 A line. Owing to its low weight and compactness, such a spectrometer will be a valuable tool for providing absolute solar irradiance throughout the EUV. This novel instrument will also be useful for cross-calibrating other EUV flight instruments and will be flown on a series of Hitchhiker Shuttle Flights and on SOHO. A preliminary version of this instrument has been fabricated and characterized, and the results are described.

  11. FIES: The high-resolution Fiber-fed Echelle Spectrograph at the Nordic Optical Telescope

    NASA Astrophysics Data System (ADS)

    Telting, J. H.; Avila, G.; Buchhave, L.; Frandsen, S.; Gandolfi, D.; Lindberg, B.; Stempels, H. C.; Prins, S.; NOT staff

    2014-01-01

    FIES is a cross-dispersed high-resolution echelle spectrograph at the 2.56 m Nordic Optical Telescope (NOT), and was optimised for throughput and stability in 2006. The major 2006 upgrade involved the relocation of FIES to a stable environment and development of a fiber bundle that offers 3 different resolution modes, and made FIES an attractive tool for the user community of the NOT. Radial-velocity stability is achieved through double-chamber active temperature control. A dedicated data reduction tool, FIEStool, was developed. As a result of these upgrades, FIES is now one of the work-horse instruments at the NOT.

  12. Implementation of interference filters in the UV-Visual Echelle Spectrograph (UVES)

    NASA Astrophysics Data System (ADS)

    Hubrig, S.; Avila, G.; Kaufer, A.; D'Odorico, S.; Dekker, H.; Schmutzer, R.; Marchesi, M.; Wolff, B.; Nesvacil, N.

    2006-06-01

    The purpose of the recent installation of eight interference filters in UVES is to isolate certain echelle orders to allow the use of a maximal slit length of 30". The typical decker height of the spectrograph slit for science operations is usually of the order of 10-12". The central wavelength of each filter was chosen to permit observations of the most important emission lines in extended objects. We discuss the performance of these filters and show the first science images obtained with the test run.

  13. ON THE INTERPRETATION OF ECHELLE DIAGRAMS FOR SOLAR-LIKE OSCILLATIONS EFFECT OF CENTRIFUGAL DISTORTION

    SciTech Connect

    Suarez, J. C.; Goupil, M. J.; Reese, D. R.; Samadi, R.; Lochard, J.; Lignieres, F.; Rieutord, M.

    2010-09-20

    This work aims at determining the impact of slow to moderate rotation on the regular patterns often present in solar-like oscillation spectra, i.e., the frequency spacings. We focus on the well-known asteroseismic diagnostic echelle diagrams, examining how rotation may modify the estimates of the large and small spacings, as well as the identification of modes. We illustrate the work with a real case: the solar-like star {eta}Bootis. We study a main-sequence 1.3 M{sub sun} star as a typical case. The modeling takes into account rotation effects on the equilibrium models through an effective gravity and on the oscillation frequencies through both perturbative and non-perturbative calculations. We compare the results of both type of calculations in the context of the regular spacings (like the small spacings and the scaled small spacings) and echelle diagrams. We show that for echelle diagrams the perturbative approach remains valid for rotational velocities up to 40-50 km s{sup -1}. We show that for the rotational velocities measured in solar-like stars, i.e., vsin i up to 20-30 km s{sup -1}, rotation effects must be taken into account in the modeling for a correct interpretation of the observed oscillations. In particular, theoretical oscillation frequencies must be corrected up to the second order in terms of rotation rate, including near degeneracy effects. For rotational velocities of about 16 km s{sup -1} and higher, diagnostics on large spacings and on modal identification through echelle diagrams can be significantly altered by the presence of the m {ne} 0 components of the rotationally split modes. We found these effects to be detectable in the observed frequency range. Analysis of the effects of rotation on small spacings and scaled small spacings reveals that these can be of the order of or even larger than surface effects, typically turbulence, microscopic diffusion, etc. Furthermore, we show that scaled spacings are significantly affected by stellar distortion even for small stellar rotational velocities (from 10 to 15 km s{sup -1}) and therefore some care must be taken when using them as indicators for probing deep stellar interiors.

  14. Grid spectrometer for visible and ultra-violet range

    NASA Astrophysics Data System (ADS)

    Damaschini, R.

    1981-03-01

    The set-up consists of two spectrometers positioned in series where the slits are replaced by grids, that is to say two-dimensional repartitions of opaque and transparent zones. We show that for a particular set-up and for particular grids, the apparatus function is identical as the classical slit spectrometer one. But for the same resolution the beam waist is greatly increased. Contrary to grid spectrometers previously proposed, the light flux is collected only on the resolved spectral element. This system is then usable for electromagnetic radiation ranges where gratings are used (I.R., V., U.V.). In addition, in principle, the system is usable for other deviation spectrometer type like mass spectrometer.

  15. Three infrared spectrometers, an atmospheric chemistry suite for the ExoMars 2016 trace gas orbiter

    NASA Astrophysics Data System (ADS)

    Korablev, Oleg; Trokhimovsky, Alexander; Grigoriev, Alexei V.; Shakun, Alexei; Ivanov, Yuriy S.; Moshkin, Boris; Anufreychik, Konstantin; Timonin, Denis; Dziuban, Ilia; Kalinnikov, Yurii K.; Montmessin, Franck

    2014-01-01

    The atmospheric chemistry suite (ACS) package is a part of the Russian contribution to the ExoMars ESA-Roscosmos mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. The near-infrared (NIR) channel is a versatile spectrometer for the spectral range of 0.7-1.6 ?m with a resolving power of 20,000. The instrument employs the principle of an echelle spectrometer with an acousto-optical tunable filter (AOTF) as a preselector. NIR will be operated in nadir, in solar occultations, and possibly on the limb. Scientific targets of NIR are the measurements of water vapor, aerosols, and dayside or nightside airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the range of 2.2-4.4 ?m targeting the resolving power of 50,000. MIR is dedicated to sensitive measurements of trace gases. The thermal infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer for the spectral range of 1.7-17 ?m with apodized resolution varying from 0.2 to 1.6 cm-1. TIRVIM is primarily dedicated to the monitoring of atmospheric temperatures and aerosol states in nadir. The present paper describes the concept of the instrument, and in more detail, the optical design and the expected parameters of its three parts channel by channel.

  16. Demonstrating and optimizing the dual dispersion and focusing functionality of grating-Fresnel lens

    NASA Astrophysics Data System (ADS)

    Zhou, Qian; Zhang, Jinchao; Ni, Kai; Pang, Jinchao; Tian, Rui

    2014-11-01

    As optical spectroscopy plays a vital role in many of modern science and engineering, there is a growing need for developing an inexpensive and miniature spectrometers. Many attempts have been tried to solve the issue. Grating-Fresnel is a hybrid device that fuses the functions of a grating and Fresnel lens into a single device. In this paper, we try to simulate reflection type and transmission type G-Fresnel device in ZAMAX. And with the aids of ZEMAX, we try to optimize the Fresnel lens, grating pattern. A better alignment for the CCD detector could also improve sensitivity of the system as well. In order to improve the resolution and sensitivity, the length between Fresnel lens and gratings will be optimized.

  17. First in-vivo trials of a fiber Bragg grating based temperature profiling system

    NASA Astrophysics Data System (ADS)

    Webb, David J.; Hathaway, M. W.; Jackson, David A.; Jones, S.; Zhang, Lin; Bennion, Ian

    2000-01-01

    We describe the results of in-vivo trials of a portable fiber Bragg grating based temperature profile monitoring system. The probe incorporates five Bragg gratings along a single fiber and prevents the gratings from being strained. Illumination is provided by a superluminescent diode, and a miniature CCD based spectrometer is used for demultiplexing. The CCD signal is read into a portable computer through a small A/D interface; the computer then calculates the positions of the center wavelengths of the Bragg gratings, providing a resolution of 0.2 degree(s)C. Tests were carried out on rabbits undergoing hyperthermia treatment of the kidney and liver via inductive heating of metallic implants and comparison was made with a commercial Fluoroptic thermometry system.

  18. Enhanced monolithic diffraction gratings with high efficiency and reduced polarization sensitivity for remote sensing applications

    NASA Astrophysics Data System (ADS)

    Triebel, Peter; Diehl, Torsten; Moeller, Tobias; Gatto, Alexandre; Pesch, Alexander; Erdmann, Lars H.; Burkhardt, Matthias; Kalies, Alexander

    2015-10-01

    Spectral imaging systems lead to enhanced sensing properties when the sensing system provides sufficient spectral resolution to identify materials from its spectral reflectance signature. The performance of diffraction gratings provides an initial way to improve instrumental resolution. Thus, subsequent manufacturing techniques of high quality gratings are essential to significantly improve the spectral performance. The ZEISS unique technology of manufacturing real-blazed profiles and as well as lamellar profiles comprising transparent substrates is well suited for the production of transmission gratings. In order to reduce high order aberrations, aspherical and free-form surfaces can be alternatively processed to allow more degrees of freedom in the optical design of spectroscopic instruments with less optical elements and therefore size and weight advantages. Prism substrates were used to manufacture monolithic GRISM elements for UV to IR spectral range. Many years of expertise in the research and development of optical coatings enable high transmission anti-reflection coatings from the DUV to the NIR. ZEISS has developed specially adapted coating processes (Ion beam sputtering, ion-assisted deposition and so on) for maintaining the micro-structure of blazed gratings in particular. Besides of transmission gratings, numerous spectrometer setups (e.g. Offner, Rowland circle, Czerny-Turner system layout) working on the optical design principles of reflection gratings. This technology steps can be applied to manufacture high quality reflection gratings from the EUV to the IR applications with an outstanding level of low stray light and ghost diffraction order by employing a combination of holography and reactive ion beam etching together with the in-house coating capabilities. We report on results of transmission gratings on plane and curved substrates and GRISM elements with enhanced efficiency of the grating itself combined with low scattered light in the angular distribution. Beside of the results of straylight measurement the actual results on improving efficiency and lowering the polarization sensitivity for transmission gratings will be discussed on theoretical simulations compared to measured data over the entire wavelength range.

  19. Grating-structured metallic microsprings

    NASA Astrophysics Data System (ADS)

    Huang, Tao; LiuThe First Two Authors Contributed Equally To This Work., Zhaoqian; Huang, Gaoshan; Liu, Ran; Mei, Yongfeng

    2014-07-01

    We fabricate grating-structured metallic microsprings with well-defined helical angles and diameters, which are self-rolled from strained nanomembranes patterned with gratings. The grating structures on the metal membrane, replicated from the imprinted polymer layer beneath, give rise to the controlled rolling direction after selective etching of the underlying sacrificial layer. The rolling direction of the grating-structured thin metal film is always perpendicular to the long side edge of gratings, offering a good way to roll up strained strips into well controlled three-dimensional (3D) microsprings simply by altering the dimension and orientation of the structured strips. The mechanical elasticity of these grating-structured metallic microsprings is verified for the potential application as a flow rate sensor. Our work may stimulate rigorous synthesis of highly functional and complex 3D helical micro and nanostructures, and hint a broad range of applications such as environmental sensors, micro-/nanoscale robots, metamaterials, etc.We fabricate grating-structured metallic microsprings with well-defined helical angles and diameters, which are self-rolled from strained nanomembranes patterned with gratings. The grating structures on the metal membrane, replicated from the imprinted polymer layer beneath, give rise to the controlled rolling direction after selective etching of the underlying sacrificial layer. The rolling direction of the grating-structured thin metal film is always perpendicular to the long side edge of gratings, offering a good way to roll up strained strips into well controlled three-dimensional (3D) microsprings simply by altering the dimension and orientation of the structured strips. The mechanical elasticity of these grating-structured metallic microsprings is verified for the potential application as a flow rate sensor. Our work may stimulate rigorous synthesis of highly functional and complex 3D helical micro and nanostructures, and hint a broad range of applications such as environmental sensors, micro-/nanoscale robots, metamaterials, etc. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00316k

  20. Fiber Bragg grating deflection sensor

    NASA Astrophysics Data System (ADS)

    Lu, Ping; Men, Liqiu; Chen, Qiying

    2008-06-01

    A new fiber-optic sensor system consisting of a fiber Bragg grating (FBG) cantilever as a transducer is proposed and demonstrated to realize simultaneous measurement of magnitude and direction of deflection. For the FBG mounted on a stainless steel cantilever, a change in the bending deflection gives rise to a monotonous shift in the Bragg resonance wavelength of the grating while the deflection direction results in either a red- or blue-shift in the Bragg wavelength due to a stretched or shrunk state of the grating. As an application of this deflection sensor, the water flow rate was measured, which showed good agreement with the theoretical analysis.

  1. Soft X-Ray Reflection Grating Technology Development for Constellation-X

    NASA Astrophysics Data System (ADS)

    Heilmann, R. K.; Akilian, M.; Chang, C.-H.; Montoya, J. C.; Zhang, Y.; Schattenburg, M. L.

    2005-12-01

    The Constellation-X mission design calls for a soft x-ray Reflection Grating Spectrometer (RGA) with light-weight reflection gratings placed in the converging beam of the Spectroscopy X-ray Telescope (SXT). Our early demonstration of high-efficiency saw-tooth reflection gratings for an in-plane diffraction geometry fabricated from off-cut anisotropically-etched silicon wafers was recently supplemented by the fabrication of high-efficiency gratings with parameters (grating period, blaze angle) suitable for an extreme off-plane mount. Patterning of large-area reflection gratings is efficiently done through Scanning Beam Interference Lithography (SBIL) on our so-called Nanoruler tool. Resolution goals require 2 arcsec or better flatness for 100-200 mm long and 0.5 mm thick thin-foil grating substrates. We designed and built an ultra-low-stress thin-foil metrology truss that allowed us to surpass this flatness requirement in combination with flattening via Magnetorheological Finishing (MRF).

  2. An electromagnetically driven lamellar grating based Fourier transform microspectrometer

    NASA Astrophysics Data System (ADS)

    Hongbin, Yu; Guangya, Zhou; Fook Siong, Chau; Feiwen, Lee; Shouhua, Wang; Mingsheng, Zhang

    2008-05-01

    A lamellar grating based Fourier transform micro-spectrometer is presented in this paper in which an electromagnetic actuator is used to drive the mobile facets of the lamellar grating to move bi-directionally. This configuration allows double-sided interferograms to be recorded, thus avoiding problems associated with zero optical path difference (OPD) identification and at the same time satisfying the requirements for large OPD scans. Based on the experimental results, a large deflection of 62.5 m is achieved when the electromagnetic microactuator is driven by a current of 129 mA. To demonstrate the system performance, the spectrum of the combined light beam of a He-Ne laser and a diode-pumped solid-state (DPSS) laser was measured. The two different wavelength components introduced were distinguished with a full width at half maximum (FWHM) spectral resolution around 3.8 nm at 632.8 nm and 3.44 nm at 532 nm.

  3. Arcus: An X-ray Grating Spectroscopy Mission

    NASA Astrophysics Data System (ADS)

    Smith, Randall K.; Arcus Collaboration

    2016-01-01

    We present the design and scientific motivation for Arcus, an X-ray grating spectrometer mission to be proposed to NASA as a MIDEX in 2016. This mission will observe structure formation at and beyond the edges of clusters and galaxies, feedback from supermassive black holes, the structure of the interstellar medium and the formation and evolution of stars. Key mission design parameters are R~3000 and >700 cm^2 of effective area at the crucial O VII and O VIII lines, with the full bandpass going from ~10-50Å. Arcus will use the silicon pore optics proposed for ESA's Athena mission, paired with off-plane gratings being developed at the University of Iowa and combined with MIT/Lincoln Labs CCDs.

  4. Plasmonic spectral filters based on diffraction gratings

    NASA Astrophysics Data System (ADS)

    Zherdev, A. Y.; Odinokov, S. B.; Lushnikov, D. S.; Ruchkina, M. A.; Zablotskiy, A. V.; Kuzin, A. A.; Smirnov, A. V.

    2015-05-01

    Method for the analysis of plasmonic gratings is developed. The mathematical research of the spectral-angular characteristics of plasmonic gratings is realized. The dependency of spectral-angular characteristics on geometric parameters of the plasmonic grating are disclosed. Samples of plasmonic gratings are obtained. The results of mathematical modeling and theoretical studies are confirmed by the experimental samples. Spectral-angular characteristics of the plasmonic gratings samples qualitatively repeat theoretically modeled characteristics.

  5. A Flexible and Modular Data Reduction Library for Fiber-fed Echelle Spectrographs

    NASA Astrophysics Data System (ADS)

    Sosnowska, D.; Lovis, C.; Figueira, P.; Modigliani, A.; Marcantonio, P. D.; Megevand, D.; Pepe, F.

    2015-09-01

    Within the ESPRESSO project a new flexible data reduction library is being built. ESPRESSO, the Echelle SPectrograph for Rocky Exoplanets and Stable Spectral Observations is a fiber-fed, high-resolution, cross-dispersed echelle spectrograph. One of its main scientific goals is to search for terrestrial exoplanets using the radial velocity technique. A dedicated pipeline is being developed. It is designed to be able to reduce data from different similar spectrographs: not only ESPRESSO, but also HARPS, HARPS-N and possibly others. Instrument specifics are configurable through an input static configuration table. The first written recipes are already tested on HARPS and HARPS-N real data and ESPRESSO simulated data. The final scientific products of the pipeline will be the extracted 1-dim and 2-dim spectra. Using these products the radial velocity of the observed object can be computed with high accuracy. The library is developed within the standard ESO pipeline environment. It is being written in ANSI C and makes use of the Common Pipeline Library (CPL). It can be used in conjunction with the ESO tools Esorex, Gasgano and Reflex in the usual way.

  6. Fiber Grating Environmental Sensing System

    DOEpatents

    Schulz, Whitten L. (Fairview, OR); Udd, Eric (Fairview, OR)

    2003-07-29

    Fiber grating environmental measurement systems are comprised of sensors that are configured to respond to changes in moisture or chemical content of the surrounding medium through the action of coatings and plates inducing strain that is measured. These sensors can also be used to monitor the interior of bonds for degradation due to aging, cracking, or chemical attack. Means to multiplex these sensors at high speed and with high sensitivity can be accomplished by using spectral filters placed to correspond to each fiber grating environmental sensor. By forming networks of spectral elements and using wavelength division multiplexing arrays of fiber grating sensors may be processed in a single fiber line allowing distributed high sensitivity, high bandwidth fiber optic grating environmental sensor systems to be realized.

  7. Bragg gratings: Optical microchip sensors

    NASA Astrophysics Data System (ADS)

    Watts, Sam

    2010-07-01

    A direct UV writing technique that can create multiple Bragg gratings and waveguides in a planar silica-on-silicon chip is enabling sensing applications ranging from individual disposable sensors for biotechnology through to multiplexed sensor networks in pharmaceutical manufacturing.

  8. First application close measurements applying the new hybrid integrated MEMS spectrometer

    NASA Astrophysics Data System (ADS)

    Grüger, Heinrich; Pügner, Tino; Knobbe, Jens; Schenk, Harald

    2013-05-01

    Grating spectrometers have been designed in many different configurations. Now potential high volume applications ask for extremely miniaturized and low cost systems. By the use of integrated MEMS (micro electro mechanical systems) scanning grating devices a less expensive single detector can be used in the NIR instead of the array detectors required for fixed grating systems. Meanwhile the design of a hybrid integrated MEMS scanning grating spectrometer has been drawn. The MEMS device was fabricated in the Fraunhofer IPMS own clean room facility. This chip is mounted on a small circuit board together with the detector and then stacked with spacer and mirror substrate. The spectrometer has been realized by stacking several planar substrates by sophisticated mounting technologies. The spectrometer has been designed for the 950nm - 1900nm spectral range and 9nm spectral resolution with organic matter analysis in mind. First applications are considered in the food quality analysis and food processing technology. As example for the use of a spectrometer with this performance the grill process of steak was analyzed. Similar measurement would be possible on dairy products, vegetables or fruit. The idea is a mobile spectrometer for in situ and on site analysis applications in or attached to a host system providing processing, data access and input-output capabilities, disregarding this would be a laptop, tablet, smart phone or embedded platform.

  9. Synchrotron radiation calibration of the EUVE variable line-spaced diffraction gratings at the NBS SURF II facility

    NASA Technical Reports Server (NTRS)

    Jelinsky, P.; Jelinsky, S. R.; Miller, A.; Vallerga, J.; Malina, R. F.

    1988-01-01

    The Extreme Ultraviolet Explorer (EUVE) has a spectrometer which utilizes variable line-spaced, plane diffraction gratings in the converging beam of a Wolter-Schwarzschild type II mirror. The gratings, microchannel plate detector, and thin film filters have been calibrated with continuum radiation provided by the NBS SURF II facility. These were calibrated in a continuum beam to find edges or other sharp spectral features in the transmission of the filters, quantum efficiency of the microchannel plate detector, and efficiency of the gratings. The details of the calibration procedure and the results of the calibration are presented.

  10. Lateral-Grating DFB Laser

    NASA Technical Reports Server (NTRS)

    Andrews, James T.; Ladany, Ivan

    1991-01-01

    Novel distributed-feedback (DFB) laser design achieves improved wavelength discrimination and increased coupling. Structure offers several significant advantages; greatly improved spectrum discrimination achieved, making it possible to obtain narrow beam, even from relatively wide laser structure. Different effects obtained, depending on whether grating interacts with mode of lowest or higher order. Such improved performance characteristics as better wavelength discrimination and increased coupling achieved because grating interacts with both sides of wave.

  11. Waveguide infrared spectrometer platform for point and standoff chemical sensing

    NASA Astrophysics Data System (ADS)

    Chadha, Suneet; Henning, Pat; Landers, Frank; Weling, Ani

    2004-03-01

    Advanced autonomous detection of chemical warfare agents and toxic industrial chemicals has long been a major military concern. At present, our capability to rapidly assess the immediate environment is severely limited and our domestic infrastructure is burdened by the meticulous procedures required to rule out false threats. While significant advances have recently been accomplished in remote spectral sensing using rugged FTIRs and point detectors, efforts towards low cost chemical discrimination have been lacking. Foster-Miller has developed a unique waveguide spectrometer which is a paradigm shift from the conventional FTIR approach. The spectrometer provides spectral discrimination over the 3-14 ?m range and will be the spectrometer platform for both active and passive detection. Foster-Miller has leveraged its innovations in infrared fiber-optic probes and the recent development of a waveguide spectrometer to build a novel infrared sensor platform for both point and stand-off chemical sensing. A monolithic wedge-grating optic provides the spectral dispersion with low cost thermopile point or array detectors picking off the diffracted wavelengths from the optic. The integrated optic provides spectral discrimination between 3-12 ?m with resolution at 16 cm-1 or better and overall optical throughput approaching 35%. The device has a fixed cylindrical grating bonded to the edge of a ZnSe conditioning "wedge". The conditioning optic overcomes limitations of concave gratings as it accepts high angle (large FOV) light at the narrow end of the wedge and progressively conditions it to be near normal to the grating. On return, the diffracted wavelengths are concentrated on the discrete or array detector (pixel) elements by the wedge, providing throughput comparable to that of an FTIR. The waveguide spectrometer coupled to ATR probes, flow through liquid cells or multipass gas cells provides significant cost advantage over conventional sampling methodologies. We will present the enabling innovations along with present performance, sensitivity expectations and discrimination algorithm strategy.

  12. Characterization of an InGaAs/InP-based Echelle mirror multiplexer for widely-tunable mid-IR sources based on quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Orbe, L. J.; Carpintero, G.; Gilles, C.; Boulila, F.; Maisons, G.; Carras, M.

    2015-03-01

    We present the experimental characterization results of a 15-to-1 wavelength multiplexer for a Distributed Feedback Quantum Cascade Laser (DFB QCL) array operating in the 7-8.5 μm (mid-long) infrared (IR) range. This design is customized for its use to combine the output from a DFB QCL array with a 0.1 μm wavelength channel spacing for spectroscopy applications, and it is proposed in order to achieve a continuous tuning range overcoming the limited tunability of a single QCLs, required for multi-gas or complex molecule detection. This multiplexer is based on an Echelle diffraction mirror grating scheme, in which multiple output waveguides are deliberately implemented in the design to de-risk for wavelength deviations in the fabrication process. We optimized the location of the input and output guides in order to allow for monolithic integration of the DFB QCL arrays, which would provide for a number of advantages such as a higher stability, less complexity and lower cost over other technologies such as external cavities. We discuss the effects over the device performance of the design, such as the diffraction effects, input channel width overlapping/crosstalk and input channel profile, which are very important to address in order to avoid unaccounted transmission losses. Other parameters such as the profile of the input and output waveguides and fabrication limitations are also discussed as their effect on the device is observed. A series of characterization tests are presented in order to compare the simulation results to the experimental data, which suggests that these multiplexers are a suitable option compared to other IR multiplexer schemes in terms of size and power transmission.

  13. Durable silver thin film coating for diffraction gratings

    DOEpatents

    Wolfe, Jesse D. (Discovery Bay, CA); Britten, Jerald A. (Oakley, CA); Komashko, Aleksey M. (San Diego, CA)

    2006-05-30

    A durable silver film thin film coated non-planar optical element has been developed to replace Gold as a material for fabricating such devices. Such a coating and resultant optical element has an increased efficiency and is resistant to tarnishing, can be easily stripped and re-deposited without modifying underlying grating structure, improves the throughput and power loading of short pulse compressor designs for ultra-fast laser systems, and can be utilized in variety of optical and spectrophotometric systems, particularly high-end spectrometers that require maximized efficiency.

  14. Dds-Based Fast Scan Spectrometer

    NASA Astrophysics Data System (ADS)

    Alekseev, E. A.; Motiyenko, R. A.; Margulès, L.

    2010-06-01

    The technique of direct digital synthesis (DDS) has two important features which enable its application in microwave spectroscopy: micro-Hz tuning resolution and extremely fast frequency switching with continuous phase. We have applied a direct digital synthesizer in a PLL-spectrometer based on backward-wave oscillator (BWO). As result we have obtained an instrument that can cover a 100 GHz bandwidth in less than one hour with high spectral resolution and high precision of frequency measurement. The application of the spectrometer to sub-millimeter wave survey spectra records of several isotopic species of astrophysical molecules (methanol, formamide, methyl formate, aziridine) will be discussed. The support of Université de Lille 1 and le Programme National de Physique Chimie du Milieu Interstellaire is gratefully acknowledged.

  15. A new spectrometer concept for Mars exploration

    NASA Astrophysics Data System (ADS)

    Rull, F.; Sansano, A.; Daz, E.; Colombo, M.; Belenguer, T.; Fernndez, M.; Guembe, V.; Canchal, R.; Dvila, B.; Snchez, A.; Laguna, H.; Ramos, G.; Gonzlez, C.; Fraga, D.; Gallego, P.; Hutchinson, I.; Ingley, R.; Snchez, J.; Canora, C. P.; Moral, A. G.; Ibarmia, S.; Prieto, J. A. R.; Manfredi, J. A. R.; Cabo, P.; Daz, C.; Jimnez, A.; Pla, J.; Margoills, R.

    2011-10-01

    The Raman Laser Spectrometer instrument is included in ExoMars program Pasteur payload and it is focused on the Mars samples analytical analysis of the geochemistry content and elemental composition of the observed crushed samples obtained by the Rover. One of the most critical Units of the RLS is the Spectrometer unit (SPU) that performs Raman spectroscopy technique and operates in a very demanding environment (operative temperature: from -40 C to 6 C) with very restrictive design constraints. It is a very small optical instrument capable to cope with 0.09 nm/pixel of resolution. The selected solution is based on a single transmisive holographic grating. At this stage of the project SPU Team is preparing the Conceptual Design Review that will take place at the end of October 2011.

  16. A new compact soft x-ray spectrometer for resonant inelastic x-ray scattering studies at PETRA III.

    PubMed

    Yin, Z; Peters, H B; Hahn, U; Agker, M; Hage, A; Reininger, R; Siewert, F; Nordgren, J; Viefhaus, J; Techert, S

    2015-09-01

    We present a newly designed compact grating spectrometer for the energy range from 210 eV to 1250 eV, which would include the K?1,2 emission lines of vital elements like C, N, and O. The spectrometer is based on a grazing incidence spherical varied line spacing grating with 2400 l/mm at its center and a radius of curvature of 58 542 mm. First, results show a resolving power of around 1000 at an energy of 550 eV and a working spectrometer for high vacuum (10(-4) mbar) environment without losing photon intensity. PMID:26429431

  17. A new compact soft x-ray spectrometer for resonant inelastic x-ray scattering studies at PETRA III

    NASA Astrophysics Data System (ADS)

    Yin, Z.; Peters, H. B.; Hahn, U.; Agker, M.; Hage, A.; Reininger, R.; Siewert, F.; Nordgren, J.; Viefhaus, J.; Techert, S.

    2015-09-01

    We present a newly designed compact grating spectrometer for the energy range from 210 eV to 1250 eV, which would include the K?1,2 emission lines of vital elements like C, N, and O. The spectrometer is based on a grazing incidence spherical varied line spacing grating with 2400 l/mm at its center and a radius of curvature of 58 542 mm. First, results show a resolving power of around 1000 at an energy of 550 eV and a working spectrometer for high vacuum (10-4 mbar) environment without losing photon intensity.

  18. Development of an ultra-high resolution diffraction grating forsoft x-rays

    SciTech Connect

    Voronov, Dmitriy L.; Cambie, Rossana; Feshchenko, Ruslan M.; Gullikson, Eric M.; Padmore, Howard A.; Vinogradov, Alexander V.; Yashchuk, Valeriy V.

    2007-08-21

    Resonant Inelastic X-ray Scattering (RIXS) is the one of themost powerful methods for investigation of the electronic structure ofmaterials, specifically of excitations in correlated electron systems.However the potential of the RIXS technique has not been fully exploitedbecause conventional grating spectrometers have not been capable ofachieving the extreme resolving powers that RIXS can utilize. State ofthe art spectrometers in the soft x-ray energy range achieve ~;0.25 eVresolution, compared to the energy scales of soft excitations andsuperconducting gap openings down to a few meV. Development ofdiffraction gratings with super high resolving power is necessary tosolve this problem. In this paper we study the possibilities offabrication of gratings of resolving power of up to 106 for the 0.5 1.5KeV energy range. This energy range corresponds to all or most of theuseful dipole transitions for elements of interest in most correlatedelectronic systems, i.e., oxygen K-edge of relevance to all oxides, thetransition metal L2,3 edges, and the M4,5 edges of the rare earths.Various approaches based on different kinds of diffraction gratings suchas deep-etched multilayer gratings, and multilayer coated echelettes arediscussed. We also present simulations of diffraction efficiency for suchgratings, and investigate the necessary fabricationtolerances.

  19. Cinematique a grande et moyenne echelles du milieu interstellaire ionise de la galaxie M33

    NASA Astrophysics Data System (ADS)

    Godbout, Steve

    Des observations Fabry-Perot Halpha, en mode balayage, ont ete faites sur deux champs dans le kiloparsec central de la galaxie Messier 33. Ces donnees ont permis d'investiguer le comportement cinematique a grande et a moyenne echelles des complexes gazeux de cette galaxie, menant a plusieurs resultats interessants. Premierement, les effets de la propagation d'une onde de densite sur la morphologie et la cinematique des complexes gazeux affectes ont ete mis en evidence. Un examen morphologique des structures, et des gradients cinematiques perpendi-culaires au bras, a grande echelle, suggere la presence de l'onde de densite. De plus, la deprojection du champ de vitesses permet de devoiler une variation azimutale moyenne de 15 km s-1 pour la composante rotative dans la region du bras sud. Deuxiemement, une verification est faite sur la relation entre la dispersion de vitesses globale et le diametre geometrique des complexes gazeux de dimensions intermediaires, montrant que cette relation n'est pas exclusive aux regions H II geantes. La relation determinee ici est similaire a celle des petites regions H II galactiques ainsi qu'a celle d'un echantillon de region H II geantes extragalactiques. La pente de cette relation est de 1.5 +/- 0.6, en accord avec ces deux autres etudes. Ensuite, un echantillon de bulles Wolf-Rayet en expansion est etudie et une comparaison est faite entre celui-ci et certaines etudes precedentes portant sur des bulles galactiques ainsi que dans le Grand Nuage de Magellan. Ceci mene a une critique de la determination d'ages cinematiques et de la sequence evolutive proposee en fonction des types spectraux des etoiles responsables. Finalement, les regions H II classiques de M33 sont investiguees pour reveler deux nouvelles relations entre les parametres cinematiques des distributions de vitesses et de dispersions de vitesses. Ces relations sont: si=7.86+/-1.69+1.62+/- 0.43sc et sc=1.22+/-0.49+0.70+/- 0.12ssi , ou si est la moyenne de la distribution de largeurs de raies, ssi en est la dispersion et sc est la dispersion de la distribution des vitesses radiales, pour un complexe gazeux donne. Ces relations mettent a jour la nature bimodale des mouvements a meme ces objets, consistant de gradients a grande echelle et de turbulence. Deux nouvelles methodes sont proposees pour evaluer la moyenne de la composante turbulente et la valeur maximale de cette derniere. Un catalogue cinematique des grands complexes gazeux de notre etude, et des restes de supernova cinematiquement interessants sont donnes en appendice.

  20. Tropospheric Emission Spectrometer and Airborne Emission Spectrometer

    NASA Technical Reports Server (NTRS)

    Glavich, T.; Beer, R.

    1996-01-01

    The Tropospheric Emission Spectrometer (TES) is an instrument being developed for the NASA Earth Observing System Chemistry Platform. TES will measure the distribution of ozone and its precursors in the lower atmosphere. The Airborne Emission Spectrometer (AES) is an aircraft precursor to TES. Applicable descriptions are given of instrument design, technology challenges, implementation and operations for both.

  1. Coherent emission of light using stacked gratings

    NASA Astrophysics Data System (ADS)

    Gong, Yongkang; Liu, Xianliang; Li, Kang; Huang, Jungang; Martinez, J. J.; Rees-Whippey, Daniel; Carver, Sara; Wang, Leiran; Zhang, Wenfu; Duan, Tao; Copner, Nigel

    2013-05-01

    The possibility of temporally and spatially coherent thermal emission has been demonstrated utilizing stacked gratings. We demonstrate that the metallic grating with narrow air slit behaves like a homogeneous slab with large permittivity and small permeability and find that the interaction between the metallic grating and the Bragg grating gives rise to impendence matching at wavelengths located in the photonic band gap of the Bragg grating, which enables the stacked gratings to perform high emission with ultranarrow spectrum and antenna-like spatial response. This paves the way towards the design of a novel infrared source platform for applications such as thermal analysis, imaging, security, biosensing, and medical diagnoses.

  2. The Coude spectrograph and echelle scanner of the 2.7 m telescope at McDonald observatory

    NASA Technical Reports Server (NTRS)

    Tull, R. G.

    1972-01-01

    The design of the Coude spectrograph of the 2.7 m McDonald telescope is discussed. A description is given of the Coude scanner which uses the spectrograph optics, the configuration of the large echelle and the computer scanner control and data systems.

  3. Coastal Research Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Lucey, Paul G.; Williams, Timothy; Horton, Keith A.

    2004-01-01

    The Coastal Research Imaging Spectrometer (CRIS) is an airborne remote sensing system designed specifically for research on the physical, chemical, and biological characteristics of coastal waters. The CRIS includes a visible-light hyperspectral imaging subsystem for measuring the color of water, which contains information on the biota, sediment, and nutrient contents of the water. The CRIS also includes an infrared imaging subsystem, which provides information on the temperature of the water. The combination of measurements enables investigation of biological effects of both natural and artificial flows of water from land into the ocean, including diffuse and point-source flows that may contain biological and/or chemical pollutants. Temperature is an important element of such measurements because temperature contrasts can often be used to distinguish among flows from different sources: for example, a sewage outflow could manifest itself in spectral images as a local high-temperature anomaly. Both the visible and infrared subsystems scan in pushbroom mode: that is, an aircraft carrying the system moves along a ground track, the system is aimed downward, and image data are acquired in across-track linear arrays of pixels. Both subsystems operate at a frame rate of 30 Hz. The infrared and visible-light optics are adjusted so that both subsystems are aimed at the same moving swath, which has across-track angular width of 15 . Data from the infrared and visible imaging subsystems are stored in the same file along with aircraft- position data acquired by a Global Positioning System receiver. The combination of the three sets of data is used to construct infrared and hyperspectral maps of scanned areas (see figure). The visible subsystem is based on a grating spectrograph and a rapid-readout charge-coupled-device camera. Images of the swatch are acquired in 256 spectral bands at wavelengths from 400 to 800 nm. The infrared subsystem, which is sensitive in a single wavelength band of 8 to 10 m, is based on a focal-plane array of HgCdTe photodetectors that are cooled to an operating temperature of 77 K by use of a closed-Stirling-cycle mechanical cooler. The nonuniformities of the HgCdTe photodetector array are small enough that the raw pixel data from the infrared subsystem can be used to recognize temperature differences on the order of 1 C. By use of a built-in blackbody calibration source that can be switched into the field of view, one can obtain bias and gain offset terms for individual pixels, making it possible to offset the effects of nonuniformities sufficiently to enable the measurement of temperature differences as small as 0.1 C.

  4. A reduction package for cross-dispersed echelle spectrograph data in IDL

    NASA Astrophysics Data System (ADS)

    Hall, Jeffrey C.; Neff, James E.

    1992-12-01

    We have written in IDL a data reduction package that performs reduction and extraction of cross-dispersed echelle spectrograph data. The present package includes a complete set of tools for extracting data from any number of spectral orders with arbitrary tilt and curvature. Essential elements include debiasing and flatfielding of the raw CCD image, removal of scattered light background, either nonoptimal or optimal extraction of data, and wavelength calibration and continuum normalization of the extracted orders. A growing set of support routines permits examination of the frame being processed to provide continuing checks on the statistical properties of the data and on the accuracy of the extraction. We will display some sample reductions and discuss the algorithms used. The inherent simplicity and user-friendliness of the IDL interface make this package a useful tool for spectroscopists. We will provide an email distribution list for those interested in receiving the package, and further documentation will be distributed at the meeting.

  5. First Studies with the Compact Echelle Spectrograph for Aeronomical Research (CESAR)

    NASA Astrophysics Data System (ADS)

    Slanger, T. G.; Hedin, J.; Matsiev, D.

    2014-12-01

    The CESAR echelle spectrograph has been in operation at Poker Flat Research Range since November 2013. High-resolution spectra (R ~ 5000) of both the nightglow and the aurorae have been obtained, and the data overlap the time period in which measurements from the PINOT campaign were made. It has been of particular interest to search for regions in which the O2(b-X) Atmospheric band system could be studied with minimal interference from auroral N2/N2+ features. The b-X 2-1 band at 697 nm is such a feature. At longer wavelengths we have ascertained that CESAR is capable of making measurements on the N(2P-2D) lines near 1040 nm, an extremely strong multiplet where the wavelength region has prevented systematic measurements. Controversially, earlier studies had indicated that these lines suffered interference from the N2 First Positive 0-0 band, which we do not find in our limited sample.

  6. Circumstellar discs in X/γ-ray binaries: first results from the Echelle spectrograph

    NASA Astrophysics Data System (ADS)

    Zamanov, R.; Stoyanov, K.; Martí, J. AA(Institute of Astronomy; National Astronomical Observatory, Bulgarian Academy of Sciences, Tsarighradsko Shose 72, BG-1784 Sofia, Bulgaria), AB(Institute of Astronomy; National Astronomical Observatory, Bulgarian Academy of Sciences, Tsarighradsko Shose 72, BG-1784 Sofia, Bulgaria), AC(Departamento de Física (EPSJ), Universidad de Jaén, Campus Las Lagunillas, A3-420, 23071, Jaén, Spain)

    2016-01-01

    Here we report our first spectral observations of Be/X-ray and γ-ray binaries obtained with the new Echelle spectrograph of the National Astronomical Observatory Rozhen. For four objects (LSI+61°303, γ Cas, MWC 148, 4U 2206+54), we report the parameters and estimate the sizes of their circumstellar discs using different emission lines (Hα, Hβ, Hγ, HeI and FeII). For MWC 148, we find that the compact object goes deeply through the disc. The flank inflections of H&alpha& can be connected with inner ring formed at the periastron passage or radiation transfer effects. We point out an intriguing similarity between the optical emission lines of the γ-ray binary MWC 148 and the well known Be star γ Cas.

  7. A Laser Frequency Comb System for Absolute Calibration of the VTT Echelle Spectrograph

    NASA Astrophysics Data System (ADS)

    Doerr, H.-P.; Steinmetz, T.; Holzwarth, R.; Kentischer, T.; Schmidt, W.

    2012-10-01

    A wavelength calibration system based on a laser frequency comb (LFC) was developed in a co-operation between the Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany and the Max-Planck-Institut für Quantenoptik, Garching, Germany for permanent installation at the German Vacuum Tower Telescope (VTT) on Tenerife, Canary Islands. The system was installed successfully in October 2011. By simultaneously recording the spectra from the Sun and the LFC, for each exposure a calibration curve can be derived from the known frequencies of the comb modes that is suitable for absolute calibration at the meters per second level. We briefly summarize some topics in solar physics that benefit from absolute spectroscopy and point out the advantages of LFC compared to traditional calibration techniques. We also sketch the basic setup of the VTT calibration system and its integration with the existing echelle spectrograph.

  8. ESPRESSO An Echelle SPectrograph for Rocky Exoplanets Search and Stable Spectroscopic Observations

    NASA Astrophysics Data System (ADS)

    Pepe, F.; Cristiani, S.; Rebolo, R.; Santos, N. C.; Dekker, H.; Mgevand, D.; Zerbi, F. M.; Cabral, A.; Molaro, P.; Di Marcantonio, P.; Abreu, M.; Affolter, M.; Aliverti, M.; Allende Prieto, C.; Amate, M.; Avila, G.; Baldini, V.; Bristow, P.; Broeg, C.; Cirami, R.; Coelho, J.; Conconi, P.; Coretti, I.; Cupani, G.; D'Odorico, V.; De Caprio, V.; Delabre, B.; Dorn, R.; Figueira, P.; Fragoso, A.; Galeotta, S.; Genolet, L.; Gomes, R.; Gonzlez Hernndez, J. I.; Hughes, I.; Iwert, O.; Kerber, F.; Landoni, M.; Lizon, J.-L.; Lovis, C.; Maire, C.; Mannetta, M.; Martins, C.; Monteiro, M. A.; Oliveira, A.; Poretti, E.; Rasilla, J. L.; Riva, M.; Santana Tschudi, S.; Santos, P.; Sosnowska, D.; Sousa, S.; Span, P.; Tenegi, F.; Toso, G.; Vanzella, E.; Viel, M.; Zapatero Osorio, M. R.

    2013-09-01

    ESPRESSO is the next generation European exoplanet hunter, combining the efficiency of a modern echelle spectrograph with extreme radial velocity and spectroscopic precision. ESPRESSO will be installed in the Combined Coud Laboratory of the VLT and linked to the four Unit Telescopes (UT) through optical coud trains, operated either with a single UT or with up to four UTs for 1.5 magnitude gain. The instrumental radial velocity precision will reach the 10 cm s-1 level and ESPRESSO will achieve a gain of two magnitudes with respect to its predecessor HARPS. This is the first VLT instrument using the incoherent combination of light from four telescopes and, together with the extreme precision requirements, calls for many innovative design solutions while ensuring the technical heritage of HARPS.

  9. A list of tantalum lines for the wavelength calibration of the Hamilton echelle spectrograph

    NASA Astrophysics Data System (ADS)

    Pakhomov, Yu. V.

    2015-10-01

    A solution to the problem of wavelength calibration for Hamilton echelle spectrographs using a hollow cathode lamp operating at the Lick Observatory Shane telescope until June 9, 2011 is presented. The spectrum of the nominally thoriumargon lamp also contains, in addition to lines of thorium and argon, a number of unknown lines identified with tantalum. Atomic data for measured lines of tantalum and thorium are used to estimate the temperature of the gas in the lamp, T = 3120 60 K. All all lines of TaI and TaII visible in the lamp spectrum have been selected from the VALD3 atomic line database, and a list compiled for use in the processing of spectral observations. The accuracy of this calibration approach is limited by the influence of hyperfine line splitting.

  10. Digital TV-echelle spectrograph for simultaneous multielemental analysis using microcomputer control

    SciTech Connect

    Davidson, J.B.; Case, A.L.

    1980-12-01

    A digital TV-echelle spectrograph with microcomputer control was developed for simultaneous multielemental analysis. The optical system is a commercially available unit originally equipped for film and photomultiplier (single element) readout. The film port was adapted for the intensifier camera. The camera output is digitized and stored in a microcomputer-controlled, 512 x 512 x 12 bit memory and image processor. Multiple spectra over the range of 200 to 800 nm are recorded in a single exposure. Spectra lasting from nanoseconds to seconds are digitized and stored in 0.033 s and displayed on a TV monitor. An inexpensive microcomputer controls the exposure, reads and displays the intensity of predetermined spectral lines, and calculates wavelengths of unknown lines. The digital addresses of unknown lines are determined by superimposing a cursor on the TV display. The microcomputer also writes into memory wavelength fiducial marks for alignment of the TV camera.

  11. High Accuracy Wavelength Calibration For A Scanning Visible Spectrometer

    SciTech Connect

    Filippo Scotti and Ronald Bell

    2010-07-29

    Spectroscopic applications for plasma velocity measurements often require wavelength accuracies ? 0.2. An automated calibration for a scanning spectrometer has been developed to achieve a high wavelength accuracy overr the visible spectrum, stable over time and environmental conditions, without the need to recalibrate after each grating movement. The method fits all relevant spectrometer paraameters using multiple calibration spectra. With a steping-motor controlled sine-drive, accuracies of ~0.025 have been demonstrated. With the addition of high resolution (0.075 aresec) optical encoder on the grading stage, greater precision (~0.005 ) is possible, allowing absolute velocity measurements with ~0.3 km/s. This level of precision requires monitoring of atmospheric temperature and pressure and of grating bulk temperature to correct for changes in the refractive index of air and the groove density, respectively.

  12. A visible-infrared imaging spectrometer for planetary missions

    NASA Technical Reports Server (NTRS)

    McCord, Thomas (Principal Investigator); Voelker, Mark; Owensby, Pam; Warren, Cris; Mooradian, Greg

    1996-01-01

    This final report summarizes the design effort for the construction of a visible-infrared imaging spectrometer for planetary missions, funded by NASA under the Planetary Instrument Definition and Development Program. The goal was to design and develop a prototype brassboard pushbroom imaging spectrometer covering the 0.35 gm to 2.5 gm spectral region using a simplified optical layout that would minimize the size, mass and parts count of the instrument by using a single holographic grating to disperse and focus light from a single slit onto both the infrared and visible focal plane arrays. Design approaches are presented and analyzed, along with problems encountered and recommended solutions to those problems. In particular, a new type of grating, incorporating two sets of rulings and a filter in a layered structure, is presented for further development.

  13. Compact Infrared Spectrometers

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis

    2009-01-01

    Concentric spectrometer forms are advantageous for constructing a variety of systems spanning the entire visible to infrared range. Spectrometer examples are given, including broadband or high resolution forms. Some issues associated with the Dyson catadioptric type are also discussed.

  14. Compact infrared spectrometers

    NASA Astrophysics Data System (ADS)

    Mouroulis, Pantazis

    2009-05-01

    Concentric spectrometer forms are advantageous for constructing a variety of systems spanning the entire visible to infrared range. Spectrometer examples are given, including broadband or high resolution forms. Some issues associated with the Dyson catadioptric type are also discussed.

  15. Rainbow trapping of surface plasmon polariton waves in metal-insulator-metal graded grating waveguide

    NASA Astrophysics Data System (ADS)

    Zeng, Chao; Cui, Yudong

    2013-03-01

    A new metal-insulator-metal (MIM) graded grating waveguide, based on surface plasmon polaritons (SPPs), is proposed and numerically investigated to realize the rainbow trapping of SPP waves. We find that the localized positions of SPP waves depend on the frequencies of the incident light. The theoretical results show that the trapping time of SPP waves can be up to 83.4 fs and the proposed compact configuration can be operated in a broad bandwidth of 90 THz. Our MIM graded grating waveguide may find significant applications on plasmonic slow-light systems, especially chip-based optical buffers and spectrometers.

  16. The Very precise Echelle SpectroPolarimeter on the Araki telescope (VESPolA)

    NASA Astrophysics Data System (ADS)

    Arasaki, Takayuki; Ikeda, Yuji; Shinnaka, Yoshiharu; Itose, Chisato; Nakamichi, Akika; Kawakita, Hideyo

    2015-06-01

    We report on the construction of a high-resolution spectropolarimeter, the Very precise Echelle SpectroPolarimeter on the Araki telescope (VESPolA). The instrument operates in the visible spectral range, i.e., 400-850 nm, and is mounted on the 1.3 m Araki telescope at the Koyama Astronomical Observatory of Kyoto Sangyo University (Kyoto, Japan). It employs an echelle-type spectrograph and a non-ripple super-achromatic half-wave plate, resulting in high polarimetric accuracy of ?P < 0.1% for linear polarization with a spectral resolution of R = 8000 at the central wavelengths and a wide wavelength coverage of ?? = 150-250 nm in a single exposure. VESPolA is designed for 1-2 m telescopes that have a Cassegrain focus. This configuration provides a dozen polarization line profiles of various nuclear species from the target spectra simultaneously, and we can therefore obtain complementary information on both the geometry and the velocity field of the nebular emission lines from the circumstellar envelopes. We evaluated the performance of our system by observing a spectroscopic standard star and several polarization standard stars during 2012-2013. VESPolA achieved a spectral resolution 7750 < R < 8250, with a polarimetric accuracy of ?P < 0.1% for linear polarization and a limiting magnitude of mv = 7.8 mag with ?P < 0.1% and an integration time of 4 hr. We show preliminary results of variable stars P Cyg, ? Lyr, and VY CMa. We observed polarization profiles across the H? and He lines, as well as the TiO absorption bands, which indicate a complex spatial distribution and velocity field of the surrounding gaseous nebulae.

  17. Transformation a Echelle Fixe et Groupe de Renormalisation pour les Objets Fractals et Multifractals

    NASA Astrophysics Data System (ADS)

    Tremblay, Real

    Dans un premier temps, la description mathematique des fractals et des multifractais est resumee. Une description de quelques-uns des principaux systemes ou apparaissent des spectres d'exposants multifractals est presentee. L'accent est mis sur deux archetypes, le modele de percolation et le modele de rupture dielectrique. Un modele original de cascade multifractale avec interactions inspire des modeles phenomenologiques de la turbulence est presente et son spectre d'exposants calcule analytiquement. Ce travail elargit la classe de modeles pour lesquels on connait le spectre d'exposants exactement. Dans la seconde partie, on trouve une analyse critique de la transformation a echelle fixe. Sont discutees plus particulierement les proprietes que doivent posseder les diagrammes de base pour obtenir une transformation invariante d'echelle. Les differentes hypotheses arbitraires de la theorie sont mises en evidence. L'une de ces hypotheses concerne le traitement auto-coherent des conditions aux frontieres. Considerant cette hypothese comme valable, la theorie utilise la distribution de trous dans un ensemble de Cantor aleatoire. Un calcul exact de cette distribution est donne ici. Enfin, en troisieme et dernier lieu, on retrouve une analyse exhaustive du probleme du crossover dans le modele de percolation avec une resistance non-nulle pour les liens normalement isolants. A l'aide du groupe de renormalisation de Migdal-Kadanoff, on montre qu'il existe un seul exposant de crossover et une seule longueur de coherence. D'autres longueurs de correlation peuvent etre definies, mais elles demeurent dans un rapport fixe le long des axes propres du groupe de renormalisation. La multifractalite est donc, pour ce modele et ceux qui peuvent etre formules de facon analogue, compatible avec l'existence d'une seule longueur de coherence. Ces resultats sont d'application directe pour les proprietes electriques des milieux desordonnes.

  18. Large aperture spatial heterodyne imaging spectrometer: Principle and experimental results

    NASA Astrophysics Data System (ADS)

    Xiangli, Bin; Cai, Qisheng; Du, Shusong

    2015-12-01

    A large aperture spatial heterodyne imaging spectrometer (LASHIS) is proposed. It is a kind of pushbroom Fourier transform ultraspectral imager with no moving parts. This imaging spectrometer, based on a Sagnac lateral shearing interferometer combined with a pair of gratings, has the advantages of high spectral resolution, high throughput and robustness. The principle of LASHIS and its spectral retrieval method are introduced. The processing chain to convert raw images to ultraspectral datacube is also described. Experimental results demonstrate the high resolving power of LASHIS with the emission spectrum of a low pressure sodium lamp.

  19. Optical design of a coastal ocean imaging spectrometer.

    PubMed

    Mouroulis, Pantazis; Green, Robert O; Wilson, Daniel W

    2008-06-01

    We present an optical design for an airborne imaging spectrometer that addresses the unique constraints imposed by imaging the coastal ocean region. A fast (F/1.8) wide field system (36 degrees) with minimum polarization dependence and high response uniformity is required, that covers the spectral range 350-1050 nm with 3 nm sampling. We show how these requirements can be achieved with a two-mirror telescope and a compact Dyson spectrometer utilizing a polarization-insensitive diffraction grating. PMID:18545620

  20. Design of airborne imaging spectrometer based on curved prism

    NASA Astrophysics Data System (ADS)

    Nie, Yunfeng; Xiangli, Bin; Zhou, Jinsong; Wei, Xiaoxiao

    2011-11-01

    A novel moderate-resolution imaging spectrometer spreading from visible wavelength to near infrared wavelength range with a spectral resolution of 10 nm, which combines curved prisms with the Offner configuration, is introduced. Compared to conventional imaging spectrometers based on dispersive prism or diffractive grating, this design possesses characteristics of small size, compact structure, low mass as well as little spectral line curve (smile) and spectral band curve (keystone or frown). Besides, the usage of compound curved prisms with two or more different materials can greatly reduce the nonlinearity inevitably brought by prismatic dispersion. The utilization ratio of light radiation is much higher than imaging spectrometer of the same type based on combination of diffractive grating and concentric optics. In this paper, the Seidel aberration theory of curved prism and the optical principles of Offner configuration are illuminated firstly. Then the optical design layout of the spectrometer is presented, and the performance evaluation of this design, including spot diagram and MTF, is analyzed. To step further, several types of telescope matching this system are provided. This work provides an innovational perspective upon optical system design of airborne spectral imagers; therefore, it can offer theoretic guide for imaging spectrometer of the same kind.

  1. A Compact, Fast, Wide-Field Imaging Spectrometer System

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis; VanGorp, Byron E.; White, Victor E.; Mumolo, Jason M.; Hebert, Daniel; Feldman, Martin

    2011-01-01

    We present test results from a compact, fast (F/1.4) imaging spectrometer system with a 33 degree field of view, operating in the 450-1650 nm wavelength region with an extended response InGaAs detector array. The system incorporates a simple two-mirror telescope and a steeply concave bilinear groove diffraction grating made with gray scale x-ray lithography techniques. High degree of spectral and spatial uniformity (97%) is achieved.

  2. Equivalent networks for SAW gratings.

    PubMed

    Koshiba, M; Mitobe, S

    1988-01-01

    An equivalent-network approach is described for the analysis of surface-acoustic-wave gratings. Circuit parameters can be theoretically determined by applying the finite-element method to an infinite array. In this approach, all of the effects of piezoelectric perturbation, mechanical perturbation, and energy storage are taken into account. To show the validity and usefulness of this approach, examples are computed for groove and metallic gratings. Both short and open circuited metallic gratings are treated. For grooves on isotropic and Y-Z LiNbO(3) substrates, the dependence of reflection characteristics on groove depth is investigated. For aluminum strips on X-112 degrees Y LiTaO(3) 34 degrees Y-X quartz, Y-Z LiNbO(3), and 128 degrees Y -X LiNbO(3) substrates, the dependence on metallization ratio is investigated in detail. PMID:18290184

  3. First results from a next-generation off-plane X-ray diffraction grating

    NASA Astrophysics Data System (ADS)

    McEntaffer, Randall; DeRoo, Casey; Schultz, Ted; Gantner, Brennan; Tutt, James; Holland, Andrew; O'Dell, Stephen; Gaskin, Jessica; Kolodziejczak, Jeffrey; Zhang, William W.; Chan, Kai-Wing; Biskach, Michael; McClelland, Ryan; Iazikov, Dmitri; Wang, Xinpeng; Koecher, Larry

    2013-08-01

    Future NASA X-ray spectroscopy missions will require high throughput, high resolving power grating spectrometers. Off-plane reflection gratings are capable of meeting the performance requirements needed to realize the scientific goals of these missions. We have identified a novel grating fabrication method that utilizes common lithographic and microfabrication techniques to produce the high fidelity groove profile necessary to achieve this performance. Application of this process has produced an initial pre-master that exhibits a radial (variable line spacing along the groove dimension), high density (> 6000 grooves/mm), laminar profile. This pre-master has been tested for diffraction efficiency at the BESSY II synchrotron light facility and diffracts up to 55 % of incident light into usable spectral orders. Furthermore, tests of spectral resolving power show that these gratings are capable of obtaining resolving powers well above 1300 ( ?/? ?) with limitations due to the test apparatus, not the gratings. Obtaining these results has provided confidence that this fabrication process is capable of producing off-plane reflection gratings for the next generation of X-ray observatories.

  4. Spectrometer for monitoring of atmospheric ozone (ozonometer)

    NASA Astrophysics Data System (ADS)

    Dobrolenskiy, Yury; Korablev, Oleg; Ionov, Dmitry; Viazovetskiy, Nikita; Tchikov, Konstantin; Krasavtsev, Valery; Moiseev, Pavel; Belyaev, Denis; Fedorova, Anna; Mantsevich, Sergey; Zhirnova, Yulia; Rumyantsev, Dmitry; Kananykhin, Igor; Viktorov, Alexey; Shatalov, Andrey; Zherebtsov, Evgeny; Kozyura, Alexey; Moryakin, Sergey

    2013-04-01

    The spectrometer for the monitoring of Earth atmospheric ozone from the board of spacecraft is being designed. The aim of the spectrometer called "Ozonometer" is global and permanent monitoring of total ozone by means of measuring spectra of scattered solar radiation in near-UV and visible range of spectrum (300 - 500 nm). This range includes Huggins absorption band of ozone in near-UV (300 - 360 nm) and nitrogen dioxide NO2 absorption bands in visible light (400 - 500 nm). The optical design of the spectrometer is based on the Rowland circle scheme with holographic concave diffractive grating. An off-axis parabolic mirror is used as an entrance objective. The CCD detector is linear with 2048 pixels. The spectral resolution is up to 0.3 nm. The spectrometer is supposed to provide nadir observations but there is also an additional optical entrance orientated to Sun hemisphere in order to measure pure solar spectra. The spectrometer is being designed within Russian special federal program "Geophysics". Among the program, a group of 4 spacecrafts "Ionosphere" is to be launched in 2014-2015. They are planned to operate at a pair of circle solar-synchronous near-polar orbits (2 spacecrafts at each orbit). Up to the present moment, the qualification model of the spectrometer has been manufactured and tested. The first performance tests were completed at optical laboratories in St. Petersburg and Moscow with the help of Hg lamps and other light sources. After that, the field atmospheric measurements have been carried out in Moscow, Orel and at Kislovodsk high-altitude atmospheric station at Caucasus. The observations have been provided at zenith direction (scattered radiation) as well as solar direct measurements. The obtained results are presented.

  5. Surface-core fiber gratings

    NASA Astrophysics Data System (ADS)

    Osório, Jonas H.; Oliveira, Ricardo; Mosquera, L.; Franco, Marcos A. R.; Heidarialamdarloo, Jamshid; Bilro, Lúcia; Nogueira, Rogério N.; Cordeiro, Cristiano M. B.

    2015-09-01

    In this paper, we report, to our knowledge, the first demonstration of the induction of long-period and Bragg gratings on surface-core optical fibers. Surface-core fibers described herein were fabricated from commercial silica tubes and germanium-doped silica rods by employing a very simple procedure. Being the core on the fiber surface, it can be sensitive to refractive index variations in the environment in which the fiber is immersed. Thus, results concerning the sensitivity of these gratings to environmental refractive index variations are presented. Besides, simulation data are presented for comparison to the experimental behavior and for projecting future steps in this research.

  6. Quartz crystal microbalance with integrated surface plasmon grating coupler.

    PubMed

    Zong, Yun; Xu, Fei; Su, Xiaodi; Knoll, Wolfgang

    2008-07-01

    We have integrated a surface plasmon grating coupler into a quartz crystal microbalance (QCM) for studying surface association/dissociation reactions. In the integrated system only QCM measurement is needed to record both the optical and the acoustic signals in the same association/dissociation reaction. This integration considerably simplifies a conventional combination instrument of a grating-coupled surface plasmon resonance (SPR) spectrometer and a quartz crystal microbalance by eliminating a number of SPR components. Moreover, in the integrated system detection of the light reflections is not needed by which one bypasses the interference problem caused by two coherent light reflections off the glass window used to seal the fluid sample and off the sensor surface. The utility of the integrated system is demonstrated using a layer-by-layer polyelectrolyte multilayer deposition protocol, in which the complete features of a conventional grating-coupled SPR/QCM combination instrument are retained, including detection of optical and acoustic changes, as well as monitoring of adsorption kinetics. PMID:18512946

  7. Advanced Fibre Bragg Grating and Microfibre Bragg Grating Fabrication Techniques

    NASA Astrophysics Data System (ADS)

    Chung, Kit Man

    Fibre Bragg gratings (FBGs) have become a very important technology for communication systems and fibre optic sensing. Typically, FBGs are less than 10-mm long and are fabricated using fused silica uniform phase masks which become more expensive for longer length or non-uniform pitch. Generally, interference UV laser beams are employed to make long or complex FBGs, and this technique introduces critical precision and control issues. In this work, we demonstrate an advanced FBG fabrication system that enables the writing of long and complex gratings in optical fibres with virtually any apodisation profile, local phase and Bragg wavelength using a novel optical design in which the incident angles of two UV beams onto an optical fibre can be adjusted simultaneously by moving just one optical component, instead of two optics employed in earlier configurations, to vary the grating pitch. The key advantage of the grating fabrication system is that complex gratings can be fabricated by controlling the linear movements of two translation stages. In addition to the study of advanced grating fabrication technique, we also focus on the inscription of FBGs written in optical fibres with a cladding diameter of several ten's of microns. Fabrication of microfibres was investigated using a sophisticated tapering method. We also proposed a simple but practical technique to filter out the higher order modes reflected from the FBG written in microfibres via a linear taper region while the fundamental mode re-couples to the core. By using this technique, reflection from the microfibre Bragg grating (MFBG) can be effectively single mode, simplifying the demultiplexing and demodulation processes. MFBG exhibits high sensitivity to contact force and an MFBG-based force sensor was also constructed and tested to investigate their suitability for use as an invasive surgery device. Performance of the contact force sensor packaged in a conforming elastomer material compares favourably to one of the best-performing commercial contact force sensors in catheterization applications. The proposed sensor features extremely high sensitivity up to 1.37-mN, miniature size (2.4-mm) that meets standard specification, excellent linearity, low hysteresis, and magnetic resonance imaging compatibility.

  8. Enhancement of detection accuracy of fiber Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Zeh, Thomas; Schweizer, Hans; Meixner, Andreas; Purde, Andreas; Koch, Alexander W.

    2004-06-01

    Over the course of the last few years, several readout techniques for fiber Bragg grating (FBG) sensors have been proposed. However, all of them suffer from specific restrictions concerning response speed, accuracy, sensor multiplexibility and cost. In the past, it was often assumed that diffraction grating spectrometers were suitable only for FBG applications with modest resolution. The achievable pixel resolution is nowadays in the range of several tens of pm. For FBG sensors with typical temperature coefficients of 5 pm/K and strain coefficients of 0.7 pm/?? this resolution is not sufficient for the majority of applications. We present a discussion on different methods for the subpixel registration of FBG spectra and we introduce a novel detection algorithm: the linear phase operator technique (LPO). Even under extreme noisy conditions LPO ensures a significant resolution enhancement by a factor of three compared to conventional algorithms and is shown to be very efficient in its implementation. The efficiencies of several conventional algorithms and LPO is compared by simulations and by means of a test bench. With slight efforts LPO is adaptable to further applications like spectrometer based Fabry-Perot sensors and other sensors with CCD detectors.

  9. Diffraction gratings used as identifying markers

    DOEpatents

    Deason, Vance A. (Idaho Falls, ID); Ward, Michael B. (Idaho Falls, ID)

    1991-01-01

    A finely detailed defraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the defraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating.

  10. Embedded high-contrast distributed grating structures

    DOEpatents

    Zubrzycki, Walter J.; Vawter, Gregory A.; Allerman, Andrew A.

    2002-01-01

    A new class of fabrication methods for embedded distributed grating structures is claimed, together with optical devices which include such structures. These new methods are the only known approach to making defect-free high-dielectric contrast grating structures, which are smaller and more efficient than are conventional grating structures.

  11. A colloidal quantum dot spectrometer.

    PubMed

    Bao, Jie; Bawendi, Moungi G

    2015-07-01

    Spectroscopy is carried out in almost every field of science, whenever light interacts with matter. Although sophisticated instruments with impressive performance characteristics are available, much effort continues to be invested in the development of miniaturized, cheap and easy-to-use systems. Current microspectrometer designs mostly use interference filters and interferometric optics that limit their photon efficiency, resolution and spectral range. Here we show that many of these limitations can be overcome by replacing interferometric optics with a two-dimensional absorptive filter array composed of colloidal quantum dots. Instead of measuring different bands of a spectrum individually after introducing temporal or spatial separations with gratings or interference-based narrowband filters, a colloidal quantum dot spectrometer measures a light spectrum based on the wavelength multiplexing principle: multiple spectral bands are encoded and detected simultaneously with one filter and one detector, respectively, with the array format allowing the process to be efficiently repeated many times using different filters with different encoding so that sufficient information is obtained to enable computational reconstruction of the target spectrum. We illustrate the performance of such a quantum dot microspectrometer, made from 195 different types of quantum dots with absorption features that cover a spectral range of 300 nanometres, by measuring shifts in spectral peak positions as small as one nanometre. Given this performance, demonstrable avenues for further improvement, the ease with which quantum dots can be processed and integrated, and their numerous finely tuneable bandgaps that cover a broad spectral range, we expect that quantum dot microspectrometers will be useful in applications where minimizing size, weight, cost and complexity of the spectrometer are critical. PMID:26135449

  12. Fluorescence imaging spectrometer optical design

    NASA Astrophysics Data System (ADS)

    Taiti, A.; Coppo, P.; Battistelli, E.

    2015-09-01

    The optical design of the FLuORescence Imaging Spectrometer (FLORIS) studied for the Fluorescence Explorer (FLEX) mission is discussed. FLEX is a candidate for the ESA's 8th Earth Explorer opportunity mission. FLORIS is a pushbroom hyperspectral imager foreseen to be embarked on board of a medium size satellite, flying in tandem with Sentinel-3 in a Sun synchronous orbit at a height of about 815 km. FLORIS will observe the vegetation fluorescence and reflectance within a spectral range between 500 and 780 nm. Multi-frames acquisitions on matrix detectors during the satellite movement will allow the production of 2D Earth scene images in two different spectral channels, called HR and LR with spectral resolution of 0.3 and 2 nm respectively. A common fore optics is foreseen to enhance by design the spatial co-registration between the two spectral channels, which have the same ground spatial sampling (300 m) and swath (150 km). An overlapped spectral range between the two channels is also introduced to simplify the spectral coregistration. A compact opto-mechanical solution with all spherical and plane optical elements is proposed, and the most significant design rationales are described. The instrument optical architecture foresees a dual Babinet scrambler, a dioptric telescope and two grating spectrometers (HR and LR), each consisting of a modified Offner configuration. The developed design is robust, stable vs temperature, easy to align, showing very high optical quality along the whole field of view. The system gives also excellent correction for transverse chromatic aberration and distortions (keystone and smile).

  13. A colloidal quantum dot spectrometer

    NASA Astrophysics Data System (ADS)

    Bao, Jie; Bawendi, Moungi G.

    2015-07-01

    Spectroscopy is carried out in almost every field of science, whenever light interacts with matter. Although sophisticated instruments with impressive performance characteristics are available, much effort continues to be invested in the development of miniaturized, cheap and easy-to-use systems. Current microspectrometer designs mostly use interference filters and interferometric optics that limit their photon efficiency, resolution and spectral range. Here we show that many of these limitations can be overcome by replacing interferometric optics with a two-dimensional absorptive filter array composed of colloidal quantum dots. Instead of measuring different bands of a spectrum individually after introducing temporal or spatial separations with gratings or interference-based narrowband filters, a colloidal quantum dot spectrometer measures a light spectrum based on the wavelength multiplexing principle: multiple spectral bands are encoded and detected simultaneously with one filter and one detector, respectively, with the array format allowing the process to be efficiently repeated many times using different filters with different encoding so that sufficient information is obtained to enable computational reconstruction of the target spectrum. We illustrate the performance of such a quantum dot microspectrometer, made from 195 different types of quantum dots with absorption features that cover a spectral range of 300 nanometres, by measuring shifts in spectral peak positions as small as one nanometre. Given this performance, demonstrable avenues for further improvement, the ease with which quantum dots can be processed and integrated, and their numerous finely tuneable bandgaps that cover a broad spectral range, we expect that quantum dot microspectrometers will be useful in applications where minimizing size, weight, cost and complexity of the spectrometer are critical.

  14. Monitoring of Laser Material Welding Process Using UV-Visible Spectrometer

    SciTech Connect

    Genc, B.; Kacar, E.; Akman, E.; Demir, A.

    2007-04-23

    UV-Visible spectrometer is used to record emission from magnesium and titanium metal plates during laser welding processing. Geometrically corrected Czerny-Turner configurations nearly eliminate defocusing problem. The Optikwerks software is used to find the optimum Czerny-Turner configuration and to choose optical elements such as grating types, mirrors focal length and diameter, and slit width. The design parameters of the uv-visible spectrometer in the wavelength range 200-1100 nm for monitoring laser material welding processing.

  15. The grating as an accelerating structure

    SciTech Connect

    Fernow, R.C.

    1991-02-01

    This report considers the use of a diffraction grating as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of a grating. Calculations are made of the strength of the accelerating modes for structures with {pi} and 2{pi} phase advance per period and for incident waves polarized with either the E or H vector along the grooves of the grating. We consider examples of using gratings in a laser linac and in a grating lens. We also briefly examine previous results published about this subject. 36 refs.

  16. Electromagnetically induced grating with maximal atomic coherence

    SciTech Connect

    Carvalho, Silvania A.; Araujo, Luis E. E. de

    2011-10-15

    We describe theoretically an atomic diffraction grating that combines an electromagnetically induced grating with a coherence grating in a double-{Lambda} atomic system. With the atom in a condition of maximal coherence between its lower levels, the combined gratings simultaneously diffract both the incident probe beam as well as the signal beam generated through four-wave mixing. A special feature of the atomic grating is that it will diffract any beam resonantly tuned to any excited state of the atom accessible by a dipole transition from its ground state.

  17. Dual transmission grating based imaging radiometer for tokamak edge and divertor plasmas

    SciTech Connect

    Kumar, Deepak; Clayton, Daniel J.; Parman, Matthew; Stutman, Dan; Tritz, Kevin; Finkenthal, Michael

    2012-10-15

    The designs of single transmission grating based extreme ultraviolet (XUV) and vacuum ultraviolet (VUV) imaging spectrometers can be adapted to build an imaging radiometer for simultaneous measurement of both spectral ranges. This paper describes the design of such an imaging radiometer with dual transmission gratings. The radiometer will have an XUV coverage of 20-200 A with a {approx}10 A resolution and a VUV coverage of 200-2000 A with a {approx}50 A resolution. The radiometer is designed to have a spatial view of 16 Degree-Sign , with a 0.33 Degree-Sign resolution and a time resolution of {approx}10 ms. The applications for such a radiometer include spatially resolved impurity monitoring and electron temperature measurements in the tokamak edge and the divertor. As a proof of principle, the single grating instruments were used to diagnose a low temperature reflex discharge and the relevant data is also included in this paper.

  18. Dual transmission grating based imaging radiometer for tokamak edge and divertor plasmas.

    PubMed

    Kumar, Deepak; Clayton, Daniel J; Parman, Matthew; Stutman, Dan; Tritz, Kevin; Finkenthal, Michael

    2012-10-01

    The designs of single transmission grating based extreme ultraviolet (XUV) and vacuum ultraviolet (VUV) imaging spectrometers can be adapted to build an imaging radiometer for simultaneous measurement of both spectral ranges. This paper describes the design of such an imaging radiometer with dual transmission gratings. The radiometer will have an XUV coverage of 20-200 A? with a ?10 A? resolution and a VUV coverage of 200-2000 A? with a ~50 A? resolution. The radiometer is designed to have a spatial view of 16, with a 0.33 resolution and a time resolution of ~10 ms. The applications for such a radiometer include spatially resolved impurity monitoring and electron temperature measurements in the tokamak edge and the divertor. As a proof of principle, the single grating instruments were used to diagnose a low temperature reflex discharge and the relevant data is also included in this paper. PMID:23127018

  19. Curved VPH gratings for novel spectrographs

    NASA Astrophysics Data System (ADS)

    Clemens, J. Christopher; O'Donoghue, Darragh; Dunlap, Bart H.

    2014-07-01

    The introduction of volume phase holographic (VPH) gratings into astronomy over a decade ago opened new possibilities for instrument designers. In this paper we describe an extension of VPH grating technology that will have applications in astronomy and beyond: curved VPH gratings. These devices can disperse light while simultaneously correcting aberrations. We have designed and manufactured two different kinds of convex VPH grating prototypes for use in off-axis reflecting spectrographs. One type functions in transmission and the other in reflection, enabling Offnerstyle spectrographs with the high-efficiency and low-cost advantages of VPH gratings. We will discuss the design process and the tools required for modelling these gratings along with the recording layout and process steps required to fabricate them. We will present performance data for the first convex VPH grating produced for an astronomical spectrograph.

  20. Bulk regeneration of optical fiber Bragg gratings.

    PubMed

    Shao, Li-Yang; Wang, Tao; Canning, John; Cook, Kevin; Tam, Hwa-Yaw

    2012-10-20

    The reliability and reproducibility of regenerated gratings for mass production is assessed through simultaneous bulk regeneration of 10 gratings. The gratings are characterized and variations are compared after each stage of fabrication, including seed (room-temperature UV fabrication), regeneration (annealing at 850C), and postannealing (annealing at 1100C). In terms of Bragg wavelength (?(B)), the seed grating variation lies within ??(B)=0.16 nm, the regenerated grating within ??(B)=0.41 nm, and the postannealed grating within ??(B)=1.42 nm. All the results are within reasonable error, indicating that mass production is feasible. The observable spread in parameters from seed to regenerated grating is clearly systematic. The postannealed spread arises from the small tension on the fiber during postannealing and can be explained by the softening of the glass when the strain temperature of silica is reached. PMID:23089767

  1. Optimal implementation of a microspectrometer based on a single flat diffraction grating.

    PubMed

    Grabarnik, Semen; Emadi, Arvin; Sokolova, Elena; Vdovin, Gleb; Wolffenbuttel, Reinoud F

    2008-04-20

    An analytical model has been developed and applied to explore the limits in the design of a highly miniaturized planar optical microspectrometer based on an imaging diffraction grating. This design tool has been validated as providing the smallest possible dimensions while maintaining acceptable spectral resolution. The resulting planar spectrometer is composed of two parallel glass plates, which contain all components of the device, including a reflective slit and an imaging diffraction grating. Fabrication is based on microelectromechanical system technology and starts with a single glass wafer; IC-compatible deposition and lithography are applied to realize the parts in aluminum, which makes the microspectrometer highly tolerant for component mismatch. The fabricated spectrometer was mounted directly on top of an image sensor and takes up a volume of only 50 mm(3). The measured spectral resolution of 6 nm (FWHM) in the 100 nm operating wavelength range (600-700 nm) is in agreement with a model calculation. PMID:18425182

  2. Calibration and characterization protocol for spectral-domain optical coherence tomography using fiber Bragg gratings.

    PubMed

    Eom, Tae Joong; Ahn, Yeh-Chan; Kim, Chang-Seok; Chen, Zhongping

    2011-03-01

    We present a calibration protocol to obtain the alignment factors of a custom-made spectrometer and the nonlinear fitting function between the measured CCD pixel domain and the wavelength domain to apply to the spectral-domain optical coherence tomography (SD-OCT) using fiber Bragg gratings. We have used five gratings with different center wavelengths covering the broadband source spectral range. All have a narrow spectral bandwidth (0.05 nm) and the same reflectivity (92%) to calibrate and align the custom-made spectrometer. The implemented SD-OCT system following the proposed protocol showed the alignment factors as 44.37 deg incident angle, 53.11 deg diffraction angle, and 70.0-mm focal length. The spectral resolution of 0.187 nm was recalculated from the alignment factors. PMID:21456856

  3. Point-by-point written fiber-Bragg gratings and their application in complex grating designs.

    PubMed

    Marshall, Graham D; Williams, Robert J; Jovanovic, Nemanja; Steel, M J; Withford, Michael J

    2010-09-13

    The point-by-point technique of fabricating fibre-Bragg gratings using an ultrafast laser enables complete control of the position of each index modification that comprises the grating. By tailoring the local phase, amplitude and spacing of the grating's refractive index modulations it is possible to create gratings with complex transmission and reflection spectra. We report a series of grating structures that were realized by exploiting these flexibilities. Such structures include gratings with controlled bandwidth, and amplitude- and phase-modulated sampled (or superstructured) gratings. A model based on coupled-mode theory provides important insights into the manufacture of such gratings. Our approach offers a quick and easy method of producing complex, non-uniform grating structures in both fibres and other mono-mode waveguiding structures. PMID:20940876

  4. [Study on an optical system of small ultraviolet imaging spectrometer with high resolution in broadband].

    PubMed

    Cong, Hai-Fang; Wang, Chun-Hui; Wang, Yu

    2013-02-01

    An ultraviolet imaging spectrometer was studied based on the principle of the small scale ultraviolet spectral instrument. The scheme composed of an off-axis parabolic mirror telescope and a single toroidal grating spectral imaging system was designed. The optimization of the optical system is the optimum processing for the parameters of the toroidal grating. The optical path function and the aberration equations of the grating were analyzed. The perfect anastigmatism conditions and imaging conditions of the single toroidal grating system were obtained. These two conditions that cannot be satisfied by the algebra calculation method limit the field of view and waveband of the spectrometer. The genetic algorithm was introduced to solve the problem. A solar-blind ultraviolet imaging spectrometer for 200-280 nm was designed to verify the design method. The optimum initial configuration was calculated and simulated. A system with F/# 5.7, focal length 102 mm and high spatial resolution was designed. The modulation transfer functions (MTF) of all fields of view are more than 0.65 in the waveband in the required Nyquist frequency (20 1p x mm(-1)). The design results indicate that the optical system theory can be applied to the small scale ultraviolet imaging spectrometer with high resolution and spectral broadband. PMID:23697155

  5. ComIXS on BACH: a compact soft x-ray spectrometer operating at Elettra

    SciTech Connect

    Cocco, Daniele; Matteucci, Maurizio; Zangrando, Marco; Bondino, Federica; Zacchigna, Michele; Plate, Mauro; Parmigiani, Fulvio; Nelles, Bruno; Prince, Kevin C.

    2004-05-12

    To accommodate increasing interest in soft x-ray inelastic scattering, a new spectrometer has been designed, constructed and commissioned at Elettra. This instrument uses as the dispersive element one of two interchangeable Variable Line Spacing (VLS) spherical gratings. The energy scan is performed by a 7 cm linear translation of a back illuminated CCD which also collects the zero order light, facilitating alignment and calibration. The two gratings have the same radius of curvature while the groove densities and the groove density variations differ by a factor four. Thus the energies focused by the gratings at a particular position differ by a factor of four. The total length of the instrument is 60 cm, the energy range covered is roughly 25-1000 eV and the expected resolving power ranges from 1000 to 5000. The spectrometer is now operating on the beamline Bach. It takes advantage of the small size of the photon spot in the experimental chamber and of the possibility to control the polarization of the incoming radiation. The small spot constitutes the virtual entrance slit, and the spectrometer collects the photons emitted in a solid angle of about 30x10 mrad2. The instrument, named ComIXS (Compact Inelastic X-ray Spectrometer), has been routinely operating since October 2002. Several experiments have already been carried out, and some results illustrating the characteristics of the instrument are described. The manufacture and testing of the blaze gratings are also discussed.

  6. A search for lithium in Pleiades brown dwarf candidates using the Keck hires echelle

    NASA Technical Reports Server (NTRS)

    Marcy, Geoffrey W.; Basri, Gibor; Graham, James R.

    1994-01-01

    We report Keck Observatory high-resolution echelle spectra of lithium at 670.8 nm in two of the lowest luminosity brown dwarf candidates in the Pleiades. These objects have estimated masses of 0.055 to 0.059 solar mass from their location on a color-magnitude diagram relative to theoretical isochrones. Stellar interior models predict that Li has not burned in them. However, we find no evidence of the Li line, at limits 100 to 1000 times below the initial abundance. This indicates that Li has in fact been depleted, presumably by nuclear processing as occurs in Pleiades stars. Interior models suggest that such large Li depletion occurs only for objects with M greater than 0.09 solar mass at the age of the Pleiades. Thus, it is unlikely that the candidates are brown dwarfs. The brown dwarf candidates present a conflict: either they have masses greater than suggested from their placement on the H-R diagram, or they do have the very low suggested masses but are nonetheless capable of destroying Li, in only 70 Myr. Until this dilemma is resolved, the photometric identification of brown dwarfs will remain difficult. Resolution may reside in higher T(sub eff) derived from optical and IR colors or in lower T(sub eff) in the interior models.

  7. An Optical Ultrahigh-Resolution Cross-dispersed Echelle Spectrograph with Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Angel, J. R. P.; Jacobsen, B.; Woolf, N.; Fugate, R. Q.; Black, J. H.; Lloyd-Hart, M.

    2002-08-01

    A prototype cross-dispersed optical echelle spectrograph of very high resolution has been designed and built at Steward Observatory and tested at the Starfire Optical Range 1.5 m telescope. It is the first spectrograph to take advantage of diffraction-limited images provided by adaptive optics in order to achieve a potential resolving power of R~600,000. The wavelength coverage in a single exposure is about 300 Å, which is approximately 100 times that of conventional spectrographs operating at comparable resolution. This was achieved by recording 60 cross-dispersed orders across the 18×18 mm2 area of the CCD detector. The total efficiency of the system, including the sky and telescope transmission, spectrograph, and CCD detector, is measured to be 1.3% at peak, much higher than that of other ultrahigh-resolution spectrographs. Sample stellar spectra with R~250,000 are presented. Observations here were made at the Starfire Optical Range 1.5 m telescope, operated by the Directed Energy Directorate, Air Force Research Laboratory.

  8. ORFEUS II echelle spectra: Absorption by H_2 in the LMC

    NASA Astrophysics Data System (ADS)

    de Boer, K. S.; Richter, P.; Bomans, D. J.; Heithausen, A.; Koornneef, J.

    We present the first detection of H_2 UV absorption profiles on the line of sight to the LMC. The star LH 10:3120 in the LMC was measured with the ORFEUS telescope and the Tue/HD echelle spectrograph during the space shuttle mission of Nov./Dec. 1996. 16 absorption lines from the Lyman band are used to derive the column densities of H_2 for the lowest 5 rotational states in the LMC gas. For these states we find a total column density of N(H_2)total=6.6 x 1018 cm^{-2} on this individual line of sight. We obtain equivalent excitation temperatures of Tex <= 50 K for the rotational ground state and Tex ~= 470 K for 1 <= J <= 5 by fitting the population densities of the rotational states to theoretical Boltzmann distributions. We conclude that UV pumping dominates the population of the higher rotational levels, as known from the H_2 gas in the Milky Way. (Research supported in part by the DARA)

  9. Extreme ultraviolet imaging spectrometer for thermospheric emissions.

    PubMed

    Torr, M R; Vitz, R C

    1982-09-01

    One of the instruments that has been developed to fly on the Space Shuttle is the Imaging Spectrometric Observatory, an array of five imaging spectrometers to cover the 300-12,000-A wavelength range. In this paper we describe the spectrometer designed to operate in the extreme ultraviolet (300-1200 A). The instrument is intended for studies of the thermosphere and magnetosphere and support of various plasma experiments to be performed from the Shuttle. The design is modular so that various components such as gratings and detectors can be changed and optimized for a range of specific studies following the first survey mission. The detector is an intensified 2-D CCD which permits simultaneous spectral and spatial imaging. The spectral multiplexing gives the spectrometer a considerable speed advantage. The instrument has a small field of view (0.65 degrees ) and is thus capable of obtaining much needed scale height information on the atmospheric EUV emissions. Operating from the Shuttle, global and temporal coverage will be obtained, and the EUV data will be enhanced by the simultaneously acquired UV, visible, and near-IR observations. PMID:20396183

  10. The Dawn Mapping Spectrometer: A Virtis-m Heritage

    NASA Astrophysics Data System (ADS)

    Coradini, A.; de Sanctis, M. C.; Capaccioni, F.; Suetta, E.; Barucci, M. A.; Drossart, P.; Jaumann, R.; McCord, T.; Russell, C. T.; Dawn Team

    The Dawn mapping spectrometer (MS) is a rebuild of the VIRTIS mapping spectrom- eter on board the ESA Rosetta mission with an operational duration of more than 2 years and flight time of more than 13 years. VIRTIS is composed of two subsystems: VIRTIS-Mapper (-M) and VIRTIS-High- resolution (-H). -M is characterised by a single optical head consisting of a Shafer telescope combined with an Offner imaging spectrometer and by two bidimensional FPAs: the VIS (0.25-1 µm) and IR (0.95-5 µm). -H is a high-resolution infrared cross-dispersed spectrometer using a prism and a grating. The 2-5 µm spectrum is dispersed in 9 orders on a focal-plane detector ma- trix. The DAWN MS spectrometer will be using only the - M channel of VIRTIS. This will permit a great mass reduction. The design uses a dual channel optical and focal design with mapping ability to 5 µm. The spectrometer consists of only three modules: optical system, 5.0 kg mass; proximity electronics, 3.0 kg and 5 W; cryocooler includ- ing driving electronics, 1.3 kg and 14 W. A 5.0 kg mechanical and thermal mounting, including the cover mechanism for the optics, accommodates the spectrometer subsys- tems. The optical system, which includes foreoptics, dispersive element, filters, focal plane assemblies as well as the cryocooler and proximity electronics is a complete re-build of the VIRTIS-M instrument. As -M, MS does not use beam-splitters. Two different groove densities are ruled on a single grating. The central part of the grating (about 30% of the pupil) is ruled with a higher groove density, which generates the higher spectral resolution needed in the visible channel. The infrared channel utilizes the outer 70% of the grating, which is ruled with a lower dual-shape groove density. The larger collecting area in the IR compensates for the lower solar irradiance in this region. The visible detector array is based on the ATMEL (former Thomson-CSF) type TH 7896 CCD detector. The IR detector used in the MS is based on a bidimen- sional array of IR-sensitive photovoltaic Mercury Cadmium Telluride coupled to sili- con CMOS multiplexer. This detector can operate at temperatures of the order of 75 K. For this reason cryocoolers have to be used.The design fully accomplishes DAWN's scientific and measurement objectives with a simple space-qualified low risk approach and high performance, reliability, heritage and cost effectiveness.

  11. Cross-fiber Bragg grating transducer

    NASA Technical Reports Server (NTRS)

    Albin, Sacharia (Inventor); Zheng, Jianli (Inventor); Lavarias, Arnel (Inventor)

    2000-01-01

    A transducer has been invented that uses specially-oriented gratings in waveguide a manner that allows the simultaneous measurement of physical phenomena (such as shear force, strain and temperature) in a single sensing element. The invention has a highly sensitive, linear response and also has directional sensitivity with regard to strain. The transducer has a waveguide with a longitudinal axis as well as two Bragg gratings. The transducer has a first Bragg grating associated with the waveguide that has an angular orientation .theta..sub.a relative to a perpendicular to the longitudinal axis such that 0.degree.<.theta..sub.a <.theta..sub.max. The second Bragg grating is associated with the waveguide in such a way that the angular orientation .theta..sub.b of the grating relative to a perpendicular to the longitudinal axis is (360.degree.-.theta..sub.max)<.theta..sub.b <360.degree.. The first Bragg grating can have a periodicity .LAMBDA..sub.a and the second Bragg grating can have a periodicity .LAMBDA..sub.b such that the periodicity .LAMBDA..sub.a of the first Bragg grating does not equal the periodicity .LAMBDA..sub.b of the second Bragg grating. The angle of the gratings can be such that .theta..sub.a =360.degree.-.theta..sub.b. The waveguide can assume a variety of configurations, including an optical fiber, a rectangular waveguide and a planar waveguide. The waveguide can be fabricated of a variety of materials, including silica and polymer material.

  12. Fixational saccades during grating detection and discrimination.

    PubMed

    Spotorno, Sara; Masson, Guillaume S; Montagnini, Anna

    2016-01-01

    We investigated the patterns of fixational saccades in human observers performing two classical perceptual tasks: grating detection and discrimination. First, participants were asked to detect a vertical or tilted grating with one of three spatial frequencies and one of four luminance contrast levels. In the second experiment, participants had to discriminate the spatial frequency of two supra-threshold gratings. The gratings were always embedded in additive, high- or low-contrast pink noise. We observed that the patterns of fixational saccades were highly idiosyncratic among participants. Moreover, during the grating detection task, the amplitude and the number of saccades were inversely correlated with stimulus visibility. We did not find a systematic relationship between saccade parameters and grating frequency, apart from a slight decrease of saccade amplitude during grating discrimination with higher spatial frequencies. No consistent changes in the number and amplitude of fixational saccades with performance accuracy were reported. Surprisingly, during grating detection, saccade number and amplitude were similar in grating-with-noise and noise-only displays. Grating orientation did not affect substantially saccade direction in either task. The results challenge the idea that, when analyzing low-level spatial properties of visual stimuli, fixational saccades can be adapted in order to extract task-relevant information optimally. Rather, saccadic patterns seem to be overall modulated by task context, stimulus visibility and individual variability. PMID:25849759

  13. High Efficiency Germanium Immersion Gratings

    SciTech Connect

    Kuzmenko, P J; Davis, P J; Little, S L; Little, L M; Bixler, J V

    2006-05-01

    We have fabricated several germanium immersion gratings by single crystal, single point diamond flycutting on an ultra-precision lathe. Use of a dead sharp tool produces groove corners less than 0.1 micron in radius and consequently high diffraction efficiency. We measured first order efficiencies in immersion of over 80% at 10.6 micron wavelength. Wavefront error was low averaging 0.06 wave rms (at 633 nm) across the full aperture. The grating spectral response was free of ghosts down to our detection limit of 1 part in 10{sup 4}. Scatter should be low based upon the surface roughness. Measurement of the spectral line profile of a CO{sub 2} laser sets an upper bound on total integrated scatter of 0.5%.

  14. Optical Design of a Compact Imaging Spectrometer for Planetary Mineralogy

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis; Sellar, R. Glenn; Wilson, Daniel W.; Shea, James J.; Green, Robert O.

    2007-01-01

    We present the design of a compact, wide-angle pushbroom imaging spectrometer suitable for exploration of solar system bodies from low orbit. The spectrometer is based on a single detector array with a broadband response that covers the range 400 to 3000 nm and provides a spectral sampling of 10 nm. The telescope has a 24-deg field of view with 600 spatially resolved elements (detector pixels). A specially designed convex diffraction grating permits optimization of the signal-to-noise ratio through the entire spectral band. Tolerances and design parameters permit the achievement of high uniformity of response through field and wavelength. The spectrometer performance is evaluated in terms of predicted spectral and spatial response functions and from the point of view of minimizing their variation through field and wavelength. The design serves as an example for illustrating the design principles specific to this type of system.

  15. Conformal carpet and grating cloaks

    NASA Astrophysics Data System (ADS)

    Schmied, Roman; Halimeh, Jad C.; Wegener, Martin

    2010-11-01

    We introduce a class of conformal versions of the previously introduced quasi-conformal carpet cloak, and show how to construct such conformal cloaks for different cloak shapes. Our method provides exact refractive-index profiles in closed mathematical form for the usual carpet cloak as well as for other shapes. By analyzing their asymptotic behavior, we find that the performance of finite-size cloaks becomes much better for metal shapes with zero average value, e.g., for gratings.

  16. HiJaK: the high-resolution J, H and K spectrometer

    NASA Astrophysics Data System (ADS)

    Muirhead, Philip S.; Hall, Zachary J.; Veyette, Mark J.

    2014-08-01

    We present the science drivers, design requirements and a preliminary design for a high-resolution, broad- bandwidth, slit-fed cross-dispersed near-infrared spectrometer for 5-meter-class telescopes. Our concept, called the High-Resolution J, H and K Spectrometer, or HiJaK, utilizes an R6 echelle in a white-pupil design to achieve high resolution in a compact configuration with a 2048 x 2048 pixel infrared detector. We present a preliminary ray-traced optical design matched to the new 4.3-meter Discovery Channel Telescope in Happy Jack, Arizona. We also discuss mechanical and cryogenic options to house our optical design.

  17. Stationary Fourier spectrometer

    NASA Astrophysics Data System (ADS)

    Junttila, M. L.

    1993-02-01

    Theoretical performances of stationary Fourier spectrometers without mechanical scanning are compared with the performance of a scanning Fourier spectrometer. In spectrometers employing amplitude-splitting interferometers the reduction of fringe visibility, due to the extended source, can be avoided resulting in high optical throughput. In a wave-front-splitting interferometer the fringe contrast depends on the size of the source. However, the wave-front-splitting double-mirror spectrometer avoids the use of a beam splitter and forms an instrument especially suited for the detection of broad band radiation. Noise characteristics, spectral response, and resolving power of the double-mirror spectrometer are theoretically considered and measured. Due to the charge coupled device based detection the sensor characteristics affect the performance of stationary spectrometers. By background subtraction the effect of detection non-uniformity can be radically reduced increasing the signal-to-noise ratio and resolution of the spectrometer. The maximum resolving power reached in measuring the spectra of two lasers was 1600.The stationary spectrometer is applicable to a wide range of measurements ranging from recording temporally variant wide-band radiation to monitoring the wavelength of lasers.

  18. Standing wave integrated Fourier transform spectrometer for imaging spectrometry in the near infrared

    NASA Astrophysics Data System (ADS)

    Osowiecki, Gal. D.; Madi, Mohammad; Shorubalko, Ivan; Philipoussis, Irne; Alberti, Edoardo; Scharf, Toralf; Herzig, Hans P.

    2015-09-01

    We show the miniaturization and parallelization of a scanning standing wave spectrometer with a long term goal of creating a compact imaging spectrometer. In our standing wave integrated Fourier transform spectrometer, light is injected with micro-lenses into several optical polymer waveguides. A piezo actuated mirror located at the waveguide end-facet can shift the interferogram to increase its sampling frequency. The spatial distribution of the standing wave intensity inside the waveguide is partially scattered out of the plane by a periodic metallic grating and recorded by a CCD camera. We present spectra acquisition for six adjacent waveguides simultaneously at a wavelength of 632.8 nm.

  19. A Fourier transform spectrometer for visible and near ultra-violet measurements of atmospheric absorption

    NASA Technical Reports Server (NTRS)

    Parsons, C. L.; Gerlach, J. C.; Whitehurst, M.

    1982-01-01

    The development of a prototype, ground-based, Sun-pointed Michelson interferometric spectrometer is described. Its intended use is to measure the atmospheric amount of various gases which absorb in the near-infrared, visible, and near-ultraviolet portions of the electromagnetic spectrum. Preliminary spectra which contain the alpha, 0.8 micrometer, and rho sigma tau water vapor absorption bands in the near-infrared are presented to indicate the present capability of the system. Ultimately, the spectrometer can be used to explore the feasible applications of Fourier transform spectroscopy in the ultraviolet where grating spectrometers were used exclusively.

  20. A Fourier transform spectrometer for visible and near ultra-violet measurements of atmospheric absorption

    NASA Astrophysics Data System (ADS)

    Parsons, C. L.; Gerlach, J. C.; Whitehurst, M.

    1982-06-01

    The development of a prototype, ground-based, Sun-pointed Michelson interferometric spectrometer is described. Its intended use is to measure the atmospheric amount of various gases which absorb in the near-infrared, visible, and near-ultraviolet portions of the electromagnetic spectrum. Preliminary spectra which contain the alpha, 0.8 micrometer, and rho sigma tau water vapor absorption bands in the near-infrared are presented to indicate the present capability of the system. Ultimately, the spectrometer can be used to explore the feasible applications of Fourier transform spectroscopy in the ultraviolet where grating spectrometers were used exclusively.

  1. A plasmonic metal grating wavelength splitter

    NASA Astrophysics Data System (ADS)

    Yu, Yue; Sun, Chen; Li, Junhao; Deng, Xiaoxu

    2015-01-01

    A plasmonic metal grating wavelength splitter is theoretically investigated and experimentally demonstrated. Based on the periodical waveguide theories, the negative real part of the propagation constant of surface plasmon polaritons (SPPs) (\\text{Re}≤ft[β \\right]<0 ) in metal grating is derived in a wavelength range which is determined by the grating parameters. The transmission prohibition at the negative \\text{Re}≤ft[β \\right] is utilized to realize the wavelength splitting by the metal grating with different grating periods and fill factors on the left and right half. The metal grating plasmonic splitter is simulated by the finite difference time domain simulation method, the characteristics of which are consistent well with theoretical predictions. The plasmonic wavelength splitter is fabricated by electron beam lithography and the ion beam etching process. The SPPs excited by an incident wavelength of 532 and 650 nm are experimentally split and observed under an optical microscope using a charge-coupled device camera.

  2. Optical gratings and grisms: developments on straylight and polarization sensitivity improved microstructures

    NASA Astrophysics Data System (ADS)

    Diehl, Torsten; Triebel, Peter; Moeller, Tobias; Gatto, Alexandre; Pesch, Alexander; Erdmann, Lars H.; Burkhardt, Matthias; Kalies, Alexander

    2015-09-01

    Spectral imaging systems lead to enhanced sensing properties when the sensing system provides sufficient spectral resolution to identify materials from its spectral reflectance signature. The performance of diffraction gratings provides an initial way to improve instrumental resolution. Thus, subsequent manufacturing techniques of high quality gratings are essential to significantly improve the spectral performance. The ZEISS unique technology of manufacturing real-blazed profiles comprising transparent substrates is well suited for the production of transmission gratings. In order to reduce high order aberrations, aspherical and free-form surfaces can be alternatively processed to allow more degrees of freedom in the optical design of spectroscopic instruments with less optical elements and therefore size and weight advantages. Prism substrates were used to manufacture monolithic GRISM elements for UV to IR spectral range. Many years of expertise in the research and development of optical coatings enable high transmission anti-reflection coatings from the DUV to the NIR. ZEISS has developed specially adapted coating processes (Ion beam sputtering, ion-assisted deposition and so on) for maintaining the micro-structure of blazed gratings in particular. Besides of transmission gratings, numerous spectrometer setups (e.g. Offner, Rowland circle, Czerny-Turner system layout) working on the optical design principles of reflection gratings. This technology steps can be applied to manufacture high quality reflection gratings from the EUV to the IR applications with an outstanding level of low stray light and ghost diffraction order by employing a combination of holography and reactive ion beam etching together with the in-house coating capabilities. We report on results of transmission, reflection gratings on plane and curved substrates and GRISM elements with enhanced efficiency of the grating itself combined with low scattered light in the angular distribution. Focusing on the straylight characteristic a measurement of the actual straylight level, preferably with extremely high precision, was performed and will be discussed in this paper. Beside of the results of straylight measurement the actual results on improving efficiency for transmission and reflection gratings will be discussed on theoretical simulations compared to measured data over the entire wavelength range.

  3. A cryogenically cooled, multidetector spectrometer for infrared astronomy

    NASA Technical Reports Server (NTRS)

    Witteborn, F. C.; Bregman, J. D.

    1984-01-01

    A liquid helium-cooled, 24 detector grating spectrometer was developed and used for low resolution astronomical observations in the 5 to 14 micron spectral range. The instrument operated on the 91 cm Kuiper Airborne Observatory, the 3 m IRTF (Mauna Kea), the 3 m Shane telescope Observatory, the 3 m Shane telescope (Lick Observatory), and the 152 cm NASA and University of Arizona telescope. The detectors are discrete Si:Bi photoconductors with individual metal oxide semiconductor field effect transistor preamplifiers operating at 4 K. The system uses a liquid helium-cooled slit, order-sorter filter, collimator mirror, grating, and camera mirror arranged in a Czerny-Turner configuration with a cold stop added between the collimator mirror and the grating. The distances between components are chosen so that the collimator mirror images the secondary mirror of the telescope onto the cold stop, thus providing a very effective baffle. Scattered radiation is effectively reduced by using liquid helium-cooled, black baffles to divide the spectrometer into three separate compartments. The system noise-equivalent flux density, when used on the 152 cm telescope from 8 to 13 microns with a resolving power of 50, is 4.4 x 10 to the minus 17th power W/sq cm micron square root of Hz. The main applications are for measuring continuum radiation levels and solid state emission and absorption features in regions of star and planet formation.

  4. Optical apparatus for forming correlation spectrometers and optical processors

    DOEpatents

    Butler, M.A.; Ricco, A.J.; Sinclair, M.B.; Senturia, S.D.

    1999-05-18

    Optical apparatus is disclosed for forming correlation spectrometers and optical processors. The optical apparatus comprises one or more diffractive optical elements formed on a substrate for receiving light from a source and processing the incident light. The optical apparatus includes an addressing element for alternately addressing each diffractive optical element thereof to produce for one unit of time a first correlation with the incident light, and to produce for a different unit of time a second correlation with the incident light that is different from the first correlation. In preferred embodiments of the invention, the optical apparatus is in the form of a correlation spectrometer; and in other embodiments, the apparatus is in the form of an optical processor. In some embodiments, the optical apparatus comprises a plurality of diffractive optical elements on a common substrate for forming first and second gratings that alternately intercept the incident light for different units of time. In other embodiments, the optical apparatus includes an electrically-programmable diffraction grating that may be alternately switched between a plurality of grating states thereof for processing the incident light. The optical apparatus may be formed, at least in part, by a micromachining process. 24 figs.

  5. Asymmetric three-beam binary optic grating

    NASA Technical Reports Server (NTRS)

    Kathman, Alan D.; Johnson, Eric G.; Scott, Miles L.

    1993-01-01

    Binary and diffractive optical components are finding many applications in optical systems and integrated optical devices. A recent application required the development of a two-dimensional diffraction grating to perform an asymmetric, three-beam fanout. In this paper, techniques are presented for the design of arbitrary fanout grating devices. Modeling and optimization processes are demonstrated for the three-beam grating. The counter-intuitive results of the initial design are discussed, and experimental data verifying performance are presented.

  6. Diffraction gratings used as identifying markers

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1991-03-26

    A finely detailed diffraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the diffraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating. 7 figures.

  7. Designing Plasmonic Gratings with Transformation Optics

    NASA Astrophysics Data System (ADS)

    Kraft, Matthias; Luo, Yu; Maier, S. A.; Pendry, J. B.

    2015-07-01

    Plasmonic gratings that support both localized and propagating plasmons have wide applications in solar cells and optical biosensing. In this paper, we report on a most unusual grating designed to capture light efficiently into surface plasmons and concentrate their energy at hot spots where the field is resonantly enhanced. The dispersion of the surface plasmons shows degeneracy points at k =0 , where, despite a strongly modulated grating, hidden symmetries forbid hybridization of plasmons traveling in opposite directions.

  8. Instrument design and test results of the new all-reflection spatial heterodyne spectrometer

    NASA Technical Reports Server (NTRS)

    Bush, Brett C.; Cotton, Daniel M.; Vickers, James C.; Chakrabarti, Supriya

    1991-01-01

    An all-reflection spatial heterodyne spectrometer (SHS) has been recently developed. The advantages over conventional high-resolution grating spectrometers are that the SHS requires no mechanical scanning, a self-compensating optical design permits easy alignment, and it is much smaller than other spectrometers of comparable resolution. Since all beam-splits and recombinations occur by reflection off of a diffraction grating, the interferometer is capable of operating well into the extreme ultraviolet (EUV) and possibly into the soft X-ray region. A description of the design and the characteristics of the instrument is presented. Also, test results, including sample interferograms as well as their Fourier-transformed spectra, at both visible and UV wavelengths are shown. Finally, we report on future developments and possible applications.

  9. Calibration of a microchannel plate based extreme ultraviolet grazing incident spectrometer at the Advanced Light Source

    SciTech Connect

    Bakeman, M. S.; Tilborg, J. van; Sokollik, T.; Baum, D.; Ybarrolaza, N.; Duarte, R.; Toth, C.; Leemans, W. P.

    2010-10-15

    We present the design and calibration of a microchannel plate based extreme ultraviolet spectrometer. Calibration was performed at the Advance Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL). This spectrometer will be used to record the single shot spectrum of radiation emitted by the tapered hybrid undulator (THUNDER) undulator installed at the LOASIS GeV-class laser-plasma-accelerator. The spectrometer uses an aberration-corrected concave grating with 1200 lines/mm covering 11-62 nm and a microchannel plate detector with a CsI coated photocathode for increased quantum efficiency in the extreme ultraviolet. A touch screen interface controls the grating angle, aperture size, and placement of the detector in vacuum, allowing for high-resolution measurements over the entire spectral range.

  10. Volume holographic gratings: fabrication and characterization

    NASA Astrophysics Data System (ADS)

    Bianco, G.; Ferrara, M. A.; Borbone, F.; Roviello, A.; Pagliarulo, V.; Grilli, S.; Ferraro, P.; Striano, V.; Coppola, G.

    2015-05-01

    Volume Holographic Gratings is designed and fabricated to obtain a simple, lightweight and cheap light deflector. The entire process, starting from the chemical preparation of the photosensitive material, to the recording of Volume Holographic Gratings and their appropriate characterization, is reported. The recording material was a new photopolymer sensitive to light at 532nm. Results showed that the recorded Volume Holographic Grating presents a very high value of the diffraction efficiency, up to 94%. In addition, a flexible material is used to write Volume Holographic Gratings.

  11. The diffraction grating - An opinionated appraisal.

    NASA Technical Reports Server (NTRS)

    Harrison, G. R.

    1973-01-01

    As a dispersing device for spectroscopy, the prism was by 1950 being supplanted by the diffraction grating, which provided broader spectrum coverage, gave higher intrinsic dispersion, and was more flexible to use. Today most gratings are three-dimensional and blazed, being embossed with thousands of identical mirrors. The relative merits of gratings in comparison with new interferometric scanning devices are examined, taking into account Fourier spectroscopy. Problems of grating ruling are discussed together with the status of ruling engines, and questions of ruling with mechanical engines.

  12. Submicron grating fabrication on GaAs

    NASA Astrophysics Data System (ADS)

    Heflinger, D.; Kirk, J.; Cordero, R.; Evans, G.

    1981-01-01

    The laboratory techniques used for the fabrication of submicron gratings in GaAs are presented. A thin (about 1250 A) film of Shipley AZ1450B photoresist on GaAs is exposed holographically with the use of the 4579 A line of argon ion laser to produce gratings with a period of approximately 0.35 micron. Data are presented that demonstrate the effects of variation of the following parameters: developer type, developer time, laser intensity, exposure time, photoresist thickness, and ion beam etching parameters. Relative grating efficiency measurements as a function of parameter variations indicate an optimum set of parameters for grating fabrication.

  13. Polarization Measurements on SUMI's TVLS Gratings

    NASA Technical Reports Server (NTRS)

    Kobayashi, K.; West, E. A.; Davis, J. M.; Gary, G. A.

    2007-01-01

    We present measurements of toroidal variable-line-space (TVLS) gratings for the Solar Ultraviolet Magnetograph Investigation (SUMI), currently being developed at the National Space Science and Technology Center (NSSTC). SUMI is a spectro-polarimeter designed to measure magnetic fields in the solar chromosphere by observing two UV emission lines sensitive to magnetic fields, the CIY line at 155nm and the MgII line at 280nm. The instrument uses a pair of TVLS gratings, to observe both linear polarizations simultaneously. Efficiency measurements were done on bare aluminum gratings and aluminum/MgF2 coated gratings, at both linear polarizations.

  14. Precise Radial Velocities with an Upgraded Advanced Fiber Optic Echelle (AFOE)

    NASA Astrophysics Data System (ADS)

    Walters, M. A.; Korzennik, S. G.; Nisenson, P.; Henry, G. W.

    2006-06-01

    The Advanced Fiber Optic Echelle (AFOE) has been used to make precise radial velocity (PRV) observations for some 12 years. The AFOE spectrograph was initially designed as a test-bed for PRV techniques for astroseismology and planet detection, and tried to provide both short term and long term stability. The resulting trade-offs between spectral resolution, range, and coverage led to a low efficiency design. In order to optimize PRVs obtained with the iodine cell technique, the spectrograph was recently upgraded, increasing the throughput and spectral coverage while reducing the maximum resolution and range. The instrument was also moved from the 60" Tillinghast telescope at the Fred Lawrence Whipple Observatory, located at Mt. Hopkins (AZ), to the 100" Hooker telescope, located at Mt. Wilson (CA). We describe the instrumental changes required for the spectrograph upgrade as well as those needed to accommodate the 100" telescope. As a result of the instrumental changes, the data configuration has changed significantly. One would like to be able to combine radial velocities obtained before the upgrade with those obtained after, but one must take care in doing so. We describe the methodology developed to allow us to use all of the PRVs together. We also detail the precision achieved for this technique, along with the inherent precision of the upgraded configuration. Finally, we present the radial velocities we have obtained for HD 185395 as an interesting example of our studies. This triple system shows large radial velocity variations. We compare the RV variations with observed photometric changes, and present period analyses for both data sets. This work is funded by NASA/JPL/SIM (subcontract no. 1259554).

  15. Cool stars: spectral library of high-resolution echelle spectra and database of stellar parameters

    NASA Astrophysics Data System (ADS)

    Montes, D.

    2013-05-01

    During the last years our group have undertake several high resolution spectroscopic surveys of nearby FGKM stars with different spectrographs (FOCES, SARG, SOFIN, FIES, HERMES). A large number of stars have been already observed and we have already determined spectral types, rotational velocities as well as radial velocities, Lithium abundance and several chromospheric activity indicators. We are working now in a homogeneous determination of the fundamental stellar parameters (T_{eff}, log{g}, ? and [Fe/H]) and chemical abundances of many elements of all these stars. Some fully reduced spectra in FITS format have been available via ftp and in the {http://www.ucm.es/info/Astrof/invest/actividad/spectra.html}{Worl Wide Web} (Montes et al. 1997, A&AS, 123, 473; Montes et al. 1998, A&AS, 128, 485; and Montes et al. 1999, ApJS, 123, 283) and some particular spectral regions of the echelle spectra are available at VizieR by Lpez-Santiago et al. 2010, A&A, 514, A97. We are now working in made accessible all the spectra of our different surveys in a Virtual Observatory ({http://svo.cab.inta-csic.es/}{VO}) compliant library and database accessible using a common web interface following the standards of the International Virtual Observatory Alliance ({http://www.ivoa.net/}{IVOA}). The spectral library includes F, G, K and M field stars, from dwarfs to giants. The spectral coverage is from 3800 to 10000 , with spectral resolution ranging from 40000 to 80000. The database will provide in addition the stellar parameters determined for these spectra using {http://cdsads.u-strasbg.fr/abs/2012arXiv1205.4879T}{StePar} (Tabernero et al. 2012, A&A, 547, A13).

  16. The science case of the PEPSI high-resolution echelle spectrograph and polarimeter for the LBT

    NASA Astrophysics Data System (ADS)

    Strassmeier, K. G.; Pallavicini, R.; Rice, J. B.; Andersen, M. I.

    2004-05-01

    We lay out the scientific rationale for and present the instrumental requirements of a high-resolution adaptive-optics Echelle spectrograph with two full-Stokes polarimeters for the Large Binocular Telescope (LBT) in Arizona. Magnetic processes just like those seen on the Sun and in the space environment of the Earth are now well recognized in many astrophysical areas. The application to other stars opened up a new field of research that became widely known as the solar-stellar connection. Late-type stars with convective envelopes are all affected by magnetic processes which give rise to a rich variety of phenomena on their surface and are largely responsible for the heating of their outer atmospheres. Magnetic fields are likely to play a crucial role in the accretion process of T-Tauri stars as well as in the acceleration and collimation of jet-like flows in young stellar objects (YSOs). Another area is the physics of active galactic nucleii (AGNs) , where the magnetic activity of the accreting black hole is now believed to be responsible for most of the behavior of these objects, including their X-ray spectrum, their notoriously dramatic variability, and the powerful relativistic jets they produce. Another is the physics of the central engines of cosmic gamma-ray bursts, the most powerful explosions in the universe, for which the extreme apparent energy release are explained through the collimation of the released energy by magnetic fields. Virtually all the physics of magnetic fields exploited in astrophysics is somehow linked to our understanding of the Sun's and the star's magnetic fields.

  17. Study of Extra-Solar Planets with the Advanced Fiber Optic Echelle

    NASA Technical Reports Server (NTRS)

    Noyes, Robert W.; Boyce, Joseph M. (Technical Monitor)

    2002-01-01

    This is the final report of NASA Grant NAG5-7505, for 'Study of Extra-solar Planets with the Advanced Fiber Optic Echelle'. This program was funded in response to our proposal submitted under NASA NRA 97-OSS-06, with a total period of performance from June 1, 1998 through Feb 28 2002. Principal Investigator is Robert W. Noyes; co-Investigators are Sylvain G. Korzennik (SAO), Peter Niserison (SAO), and Timothy M. Brown (High Altitude Observatory). Since the start of this program we have carried out more than 30 observing runs, typically of 5 to 7 days duration. We obtained a total of around 2000 usable observations of about 150 stars, where a typical observation consists of 3 exposures of 10 minutes each. Using this data base we detected thc two additional planetary companions to the star Upsilon Andromedae. This detection was made independently of, and essentially simultaneously with, a similar detection by the Berkeley group (Marcy et al): the fact that two data sets were completely independent and gave essentially the same orbital parameters for this three-planet system gave a strong confirmation of this important result. We also extended our previous detection of the planet orbiting Rho Coronae Borealis to get a better determination of its orbital eccentricity: e=0.13 +/- 0.05. We detected a new planet in orbit around the star HD 89744, with orbital period 256 days, semi-major axis 0.88 AU, eccentricity 0.70, and minimum mass m sini = 7.2 m(sub Jup). This discovery is significant because of the very high orbital eccentricity, arid also because HD 89744 has both high metallicity [Fe/H] and at the same time a low [C/Fe] abundance ratio.

  18. [Study and design on Dyson imaging spectrometer in spectral broadband with high resolution].

    PubMed

    Yan, Ling-Wei

    2014-04-01

    The paper designs and improves a telecentric imaging spectrometer, the Dyson imaging spectrometer. The optical structure of the imaging spectrometer is simple and compact, which is only composed of a hemispherical lens and a concave grating. Based on the Rowland circle and refraction theory, the broadband anastigmatic imaging condition of Dyson imaging spectrometer which is the ratio of the grating radius and hemispherical lens radius has been analyzed. By imposing this condition for two different wavelengths, the parameters of the optical system presenting low aberrations and excellent imaging quality are obtained. To make the design spectrometer more suitable for the engineering application, the paper studies the method making the detector not to attach the surface of the hemispherical lens. A design example using optimal conditions was designed to prove our theory. The Dyson imaging spectrometer of which the imaging RMS radii are less than 2.5 microm and the advanced spectrometer of which the imaging RMS radii are less than 8 microm, with NA 0.33, waveband 0.38-1.7 microm and the slit length 15 mm, have been obtained. The design method and results are more feasible and predominant, and can be applied in the areas of the industry and remote sensing. PMID:25007644

  19. Ultraviolet-Infrared Mapping Interferometic Spectrometer

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Prism and grating spectrometers have been the defacto devices for spectral mapping and imaging (hereafter referred to as hyperspectra). We have developed a new, hybrid instrument with many superior capabilities, the Digital Array Scanned Interferometer, DASI. The DASI performs the hyperspectral data acquisition in the same way as a grating or prism spectrograph, but retains the substantial advantages of the two-beam (Michelson) interferometer with additional capabilities not possessed by either of the other devices. The DASI is capable of hyperspectral studies in virtually any space or surface environment at any wavelength from below 50 nm to beyond 12 microns with available array detectors. By our efforts, we have defined simple, low cost, no-moving parts DASI's capable of carrying out hyperspectral science measurements for solar system exploration missions, e.g. for martian, asteroid, lunar, or cometary surveys. DASI capabilities can be utilized to minimize cost, weight, power, pointing, and other physical requirements while maximizing the science data return for spectral mapping missions. Our success in the development of DASI's has become and continues to be an important influence on the efforts of the best research groups developing remote sensing instruments for space and other applications.

  20. Development, characterization and application of compact spectrometers based on MEMS with in-plane capacitive drives

    NASA Astrophysics Data System (ADS)

    Kenda, A.; Kraft, M.; Tortschanoff, A.; Scherf, Werner; Sandner, T.; Schenk, Harald; Luettjohann, Stephan; Simon, A.

    2014-05-01

    With a trend towards the use of spectroscopic systems in various fields of science and industry, there is an increasing demand for compact spectrometers. For UV/VIS to the shortwave near-infrared spectral range, compact hand-held polychromator type devices are widely used and have replaced larger conventional instruments in many applications. Still, for longer wavelengths this type of compact spectrometers is lacking suitable and affordable detector arrays. In perennial development Carinthian Tech Research AG together with the Fraunhofer Institute for Photonic Microsystems endeavor to close this gap by developing spectrometer systems based on photonic MEMS. Here, we review on two different spectrometer developments, a scanning grating spectrometer working in the NIR and a FT-spectrometer accessing the mid-IR range up to 14 μm. Both systems are using photonic MEMS devices actuated by in-plane comb drive structures. This principle allows for high mechanical amplitudes at low driving voltages but results in gratings respectively mirrors oscillating harmonically. Both systems feature special MEMS structures as well as aspects in terms of system integration which shall tease out the best possible overall performance on the basis of this technology. However, the advantages of MEMS as enabling technology for high scanning speed, miniaturization, energy efficiency, etc. are pointed out. Whereas the scanning grating spectrometer has already evolved to a product for the point of sale analysis of traditional Chinese medicine products, the purpose of the FT-spectrometer as presented is to demonstrate what is achievable in terms of performance. Current developments topics address MEMS packaging issues towards long term stability, further miniaturization and usability.

  1. Optomechanical Alignment of the Grating Wheel Mechanism for a Ground-based, Cryogenic, Near-Infrared Astronomy Instrument

    NASA Technical Reports Server (NTRS)

    Gutkowski, Sharon M.; Ohl, Raymond G.; Hagopian, John G.; Kraft, Stephen E.; Mentzell, J. Eric; Schepis, Joseph P.; Sparr, Leroy M.; Greenhouse, Matthew A.; Hyland, Jason; Mackenty, John W.

    2003-01-01

    We describe the population, optomechanical alignment, and alignment verification of near-infrared gratings on the grating wheel mechanism (GWM) for the Infrared Multi- Object Spectrometer (IRMOS). IRMOS is a cryogenic (80 K) facility instrument for the Mayall Telescope (3.8 m) at Kitt Peak National Observatory and a MEMS spectrometer concept demonstrator for NASA's James Webb Space Telescope. The IRMOS optics, bench, and mechanisms are predominantly made of Al 6061 -T651. The GWM consists of 13 planar diffraction gratings and one flat imaging mirror (58 x 57 mm), each mounted at a unique compound angle on a 31.8 cm diameter gear. The Al 6061 grating substrates are stress relieved for enhanced cryogenic performance and the optical surface is replicated from an off-the-shelf master. The imaging mirror is diamond turned and post-polished. The grating mechanism spans a projected diameter of approximately 48cm when fully assembled, utilizes several flexure designs throughout the system to accommodate thermal gradient situations, and is controlled using custom software with an off-the-shelf controller. Each optic is aligned in six degrees of freedom relative to the GWM coordinate system, which is defined relative to an optical alignment cube mounted at the center of the gear. The tip/tilt (Rx, Ry) orientation of a given grating is measured using the zero-order return from an autocollimating theodolite. Each optic's mount includes a one-piece shim located between the optic and the gear. The shim is machined to fine align each optic. We also describe alignment verification, where grating diffractive properties are compared to model predictions.

  2. Ultra efficient silicon nitride grating coupler with bottom grating reflector.

    PubMed

    Zou, Jinghui; Yu, Yu; Ye, Mengyuan; Liu, Lei; Deng, Shupeng; Zhang, Xinliang

    2015-10-01

    We theoretically propose a silicon nitride (Si(3)N(4)) grating coupler (GC) with both ultrahigh efficiency and simplified fabrication processes. Instead of using a bottom distributed Bragg reflector (DBR) or metal reflector, a bottom Si grating reflector (GR) with comparable reflectivity is utilized to improve the coupling efficiency. The fully etched Si GR is designed based on an industrially standard silicon-on-insulator (SOI) wafer with 220 nm top Si layer. By properly adjusting the trench width and period length of the Si GR, a high reflectivity over 90% is obtained. The Si(3)N(4) GC is optimized based on a common 400 nm Si(3)N(4) layer sitting on the Si GR with a SiO(2) separation layer. With an appropriate distance between the Si(3)N(4) GC and bottom Si GR, a low coupling loss of -1.47 dB is theoretically obtained using uniform GC structure. A further record ultralow loss of -0.88 dB is predicted by apodizing the Si(3)N(4) GC. The specific fabrication processes and tolerance are also investigated. Compared with DBR, the bottom Si GR can be easily fabricated by single step of patterning and etching, simplifying the fabrication processes. PMID:26480144

  3. Volume Bragg grating stabilized spectrally narrow Tm fiber laser.

    PubMed

    McComb, Timothy; Sudesh, Vikas; Richardson, Martin

    2008-04-15

    A Tm-doped large mode area (LMA) silica fiber laser has been locked to a stable wavelength of 2,053.9 nm using a volume Bragg grating (VBG). The measured spectral width of the laser output was <300 pm, limited by the spectrometer resolution. Although this laser had modest output (approximately 5W) and slope efficiency (41%), this new approach to spectrally limiting the output of LMA fiber lasers is inherently extendable to kilowatt powers, opening up several applications including high-power pulsed fiber lasers and spectral beam combining. Performance characteristics of the laser compared to one using a dielectric mirror as a high reflector are described, and the results imply low VBG losses. PMID:18414564

  4. Fiber optic diffraction grating maker

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1991-05-21

    A compact and portable diffraction grating maker is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate. 4 figures.

  5. Fiber optic diffraction grating maker

    DOEpatents

    Deason, Vance A.; Ward, Michael B.

    1991-01-01

    A compact and portable diffraction grating maker comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate.

  6. Grating Observation of GRB020813

    NASA Astrophysics Data System (ADS)

    Ricker, George

    2001-09-01

    The SXC on HETE has just localized a very bright (>10 Crab) GRB to an accuracy of 1 arcmin. Within minutes of the burst location being disseminated, an optical transient was discovered in the SXC error box. HETE is expected to detect only 2-3 such events per year with the SXC. Since this burst has some X-ray characteristics reminescent of GRB011121 (Reeves et al 2002), a grating observation with Chandra could establish definitively whether hydrogen-like emission lines from non-iron metals are characteristic of bright GRBs, as is predicted by the "supranova" model (Vietri and Stella 1999).

  7. Nanoporous polymeric transmission gratings for high-speed humidity sensing.

    PubMed

    Shi, Jinjie; Hsiao, Vincent K S; Huang, Tony Jun

    2007-11-21

    Nanoporous polymeric transmission gratings are demonstrated to be an excellent platform for high-speed optical humidity sensing. The grating structures were fabricated with a modified holographic, polymer-dispersed liquid crystal (H-PDLC) system. The sensing mechanism was based on changes in the relative transmission associated with the adsorption and desorption of water vapour by nanopores. The spectral changes due to varying humidity levels were measured by a spectrometer and compared with the calculated results based on the coupled wave theory. When the relative humidity (RH) changed from 40% to 95%, the relative transmission at 475 nm increased from 6.3% to 46.6% and that at 702 nm increased from 4% to 64%; these results indicate the sensor's high sensitivity. In addition, the sensor demonstrated excellent reversibility and reproducibility over a large RH range (from 20% to 100% RH). Moreover, the response time of the sensor was measured to be less than 350 ms, making it suitable for many high-speed humidity-sensing applications. PMID:21730475

  8. Composite Spectrometer Prisms

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Page, N. A.; Rodgers, J. M.

    1985-01-01

    Efficient linear dispersive element for spectrometer instruments achieved using several different glasses in multiple-element prism. Good results obtained in both two-and three-element prisms using variety of different glass materials.

  9. A Simple Raman Spectrometer.

    ERIC Educational Resources Information Center

    Blond, J. P.; Boggett, D. M.

    1980-01-01

    Discusses some basic physical ideas about light scattering and describes a simple Raman spectrometer, a single prism monochromator and a multiplier detector. This discussion is intended for British undergraduate physics students. (HM)

  10. Fourier Transform Spectrometer System

    NASA Technical Reports Server (NTRS)

    Campbell, Joel F. (Inventor)

    2014-01-01

    A Fourier transform spectrometer (FTS) data acquisition system includes an FTS spectrometer that receives a spectral signal and a laser signal. The system further includes a wideband detector, which is in communication with the FTS spectrometer and receives the spectral signal and laser signal from the FTS spectrometer. The wideband detector produces a composite signal comprising the laser signal and the spectral signal. The system further comprises a converter in communication with the wideband detector to receive and digitize the composite signal. The system further includes a signal processing unit that receives the composite signal from the converter. The signal processing unit further filters the laser signal and the spectral signal from the composite signal and demodulates the laser signal, to produce velocity corrected spectral data.

  11. Microbolometer imaging spectrometer.

    PubMed

    Johnson, William R; Hook, Simon J; Shoen, Steven M

    2012-03-01

    Newly developed, high-performance, long-wave- and mid-wave-IR Dyson spectrometers offer a compact, low-distortion, broadband, imaging spectrometer design. The design is further accentuated when coupled to microbolometer array technology. This novel coupling allows radiometric and spectral measurements of high-temperature targets. It also serves to be unique since it allows for the system to be aligned warm. This eliminates the need for cryogenic temperature cycling. Proof of concept results are shown for a spectrometer with a 7.5 to 12.0 ?m spectral range and approximately 20 nm per spectral band (~200 bands). Results presented in this Letter show performance for remote hot targets (>200 C) using an engineering grade spectrometer and IR commercial lens assembly. PMID:22378399

  12. Tilt sensitivity of the two-grating interferometer

    SciTech Connect

    Anderson, Christopher N.; Naulleau, Patrick P.

    2008-01-30

    Fringe formation in the two-grating interferometer is analyzed in the presence of a small parallelism error between the diffraction gratings assumed in the direction of grating shear. Our analysis shows that with partially coherent illumination, fringe contrast in the interference plane is reduced in the presence of nonzero grating tilt with the effect proportional to the grating tilt angle and the grating spatial frequencies. Our analysis also shows that for a given angle between the gratings there is an angle between the final grating and the interference plane that optimizes fringe contrast across the field.

  13. Advanced astigmatism-corrected tandem Wadsworth mounting for small-scale spectral broadband imaging spectrometer.

    PubMed

    Lei, Yu; Lin, Guan-yu

    2013-01-01

    Tandem gratings of double-dispersion mount make it possible to design an imaging spectrometer for the weak light observation with high spatial resolution, high spectral resolution, and high optical transmission efficiency. The traditional tandem Wadsworth mounting is originally designed to match the coaxial telescope and large-scale imaging spectrometer. When it is used to connect the off-axis telescope such as off-axis parabolic mirror, it presents lower imaging quality than to connect the coaxial telescope. It may also introduce interference among the detector and the optical elements as it is applied to the short focal length and small-scale spectrometer in a close volume by satellite. An advanced tandem Wadsworth mounting has been investigated to deal with the situation. The Wadsworth astigmatism-corrected mounting condition for which is expressed as the distance between the second concave grating and the imaging plane is calculated. Then the optimum arrangement for the first plane grating and the second concave grating, which make the anterior Wadsworth condition fulfilling each wavelength, is analyzed by the geometric and first order differential calculation. These two arrangements comprise the advanced Wadsworth mounting condition. The spectral resolution has also been calculated by these conditions. An example designed by the optimum theory proves that the advanced tandem Wadsworth mounting performs excellently in spectral broadband. PMID:23292378

  14. Designing the acousto-optical cell for optical spectrometer incorporated into the Guillermo Haro Astrophysical Observatory

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Arellanes Bernabe, Adan Omar; Chavushyan, Vahram

    2013-09-01

    Optical spectrometer of the Guillermo Haro astrophysical observatory (Mexico) exploits mechanically removable traditional static diffraction gratings as dispersive elements. There is a set of the static gratings with the slit-density 50 - 600 lines/mm and optical apertures 9 cm x 9 cm that provide the first order spectral resolution from 9.6 to 0.8 A/pixel, respectively, in the range 400 - 1000 nm. However, the needed mechanical manipulations, namely, replacing the static diffraction gratings with various resolutions and following recalibration of spectrometer within studying even the same object are inconvenient and lead to losing rather expensive observation time. We suggest exploiting an acousto-optical cell, i.e. the dynamic diffraction grating tunable electronically, as dispersive element in that spectrometer. Involving the acousto-optical technique, which can potentially provide electronic control over the spectral resolution and the range of observations, leads to possible eliminating the above-mentioned demerits and to improving the efficiency of analysis.

  15. Integrated Bragg gratings in spiral waveguides.

    PubMed

    Simard, Alexandre D; Painchaud, Yves; LaRochelle, Sophie

    2013-04-01

    Over the last two decades, many filters requiring custom spectral responses were obtained from photo-inscribed fiber Bragg gratings because of the flexibility inherent to this technology. However, Bragg gratings in silicon waveguides have the potential to provide faster and more efficient tuning capabilities when compared to optical fiber devices. One drawback is that Bragg gratings filters with elaborate spectral amplitude and phase responses often require a long interaction length, which is not compatible with current integration trends in CMOS compatible photonic circuits. In this paper, we propose to make Bragg gratings in spiral-shaped waveguides in order to increase their lengths while making them more compact. The approach preserves the flexibility of regular straight grating structures. More specifically, we demonstrate 2-mm long gratings wrapped in an area of 200 m x 190 m without any spectral degradation due to waveguide curvature. Furthermore, we interleave three spiral waveguides with integrated gratings thereby tripling the density and demonstrate good phase compensation for each of them. Finally, we show that this approach is compatible with phase-apodization of the grating coupling coefficient. PMID:23571986

  16. Inquiry with Laser Printer Diffraction Gratings

    ERIC Educational Resources Information Center

    Van Hook, Stephen J.

    2007-01-01

    The pages of "The Physics Teacher" have featured several clever designs for homemade diffraction gratings using a variety of materials--cloth, lithographic film, wire, compact discs, parts of aerosol spray cans, and pseudoliquids and pseudosolids. A different and inexpensive method I use to make low-resolution diffraction gratings takes advantage

  17. Inquiry with Laser Printer Diffraction Gratings

    ERIC Educational Resources Information Center

    Van Hook, Stephen J.

    2007-01-01

    The pages of "The Physics Teacher" have featured several clever designs for homemade diffraction gratings using a variety of materials--cloth, lithographic film, wire, compact discs, parts of aerosol spray cans, and pseudoliquids and pseudosolids. A different and inexpensive method I use to make low-resolution diffraction gratings takes advantage…

  18. Scatterometry measurement of asymmetric gratings

    NASA Astrophysics Data System (ADS)

    Li, Jie; Hwu, Justin J.; Liu, Yongdong; Rabello, Silvio; Liu, Zhuan; Hu, Jiangtao

    2009-12-01

    Scatterometry has been used extensively for the characterization of critical dimensions (CD) and detailed sidewall profiles of periodic structures in microelectronics fabrication processes. So far the majority of applications are for symmetric gratings. In most cases devices are designed to be symmetric although errors could occur during fabrication process and result in undesired asymmetry. The problem with conventional optical scatterometry techniques lies in the lack of capability to distinguish between left and right asymmetries. In this work we investigate the possibility of measuring grating asymmetry using Mueller matrix spectroscopic ellipsometry (MM-SE). A patterned hard disk prepared by nano-imprint technique is used for the study. The relief image on the disk sometimes has asymmetrical sidewall profile, presumably due to the uneven separation of the template from the disk. The undesired tilting resist profile causes difficulties to the downstream processes or even makes them fail. Cross-section SEM reveals that the asymmetrical resist lines are typically tilted towards the outer diameter direction. The simulation and experimental data show that certain Mueller matrix elements are proportional to the direction and amplitude of profile asymmetry, providing a direct indication to the sidewall tilting. The tilting parameter can be extracted using rigorous optical critical dimension (OCD) modeling or calibration method. We demonstrate that this technique has good sensitivity for measuring and distinguishing left and right asymmetry caused by sidewall tilting, and can therefore be used for monitoring processes, such as lithography and etch processing, for which symmetric structures are desired.

  19. s-process enrichment in the planetary nebula NGC 3918. Results from deep echelle spectrophotometry

    NASA Astrophysics Data System (ADS)

    García-Rojas, J.; Madonna, S.; Luridiana, V.; Sterling, N. C.; Morisset, C.; Delgado-Inglada, G.; Toribio San Cipriano, L.

    2015-09-01

    The chemical content of the planetary nebula NGC 3918 is investigated through deep, high-resolution (R ˜ 40 000) UVES (Ultraviolet-Visual Echelle Spectrograph) at VLT (Very Large Telescope) spectrophotometric data. We identify and measure more than 750 emission lines, making ours one of the deepest spectra ever taken for a planetary nebula. Among these lines we detect very faint lines of several neutron-capture elements (Se, Kr, Rb, and Xe), which enable us to compute their chemical abundances with unprecedented accuracy, thus constraining the efficiency of the s-process and convective dredge-up in NGC 3918 progenitor star. We find that Kr is strongly enriched in NGC 3918 and that Se is less enriched than Kr, in agreement with the results of previous papers and with predicted s-process nucleosynthesis. We also find that Xe is not as enriched by the s-process in NGC 3918 as is Kr and, therefore, that neutron exposure is typical of modestly subsolar metallicity asymptotic giant branch (AGB) stars. A clear correlation is found when representing [Kr/O] versus log(C/O) for NGC 3918 and other objects with detection of multiple ions of Kr in optical data, confirming that carbon is brought to the surface of AGB stars along with s-processed material during third dredge-up episodes, as predicted by nucleosynthesis models. We also detect numerous refractory element lines (Ca, K, Cr, Mn, Fe, Co, Ni, and Cu) and a large number of metal recombination lines of C, N, O, and Ne. We compute physical conditions from a large number of diagnostics, which are highly consistent among themselves assuming a three-zone ionization scheme. Thanks to the high ionization of NGC 3918 we detect a large number of recombination lines of multiple ionization stages of C, N, O and Ne. The abundances obtained for these elements by using recently determined state-of-the-art ionization correction factor (ICF) schemes or simply adding ionic abundances are in very good agreement, demonstrating the quality of the recent ICF scheme for high-ionization planetary nebulae.

  20. Heavy Element Abundances in Planetary Nebulae from Deep Optical Echelle Spectroscopy

    NASA Astrophysics Data System (ADS)

    Mashburn, Amanda; Sterling, Nicholas C.; Dinerstein, Harriet L.; Garofali, Kristen; Jensema, Rachael; Turbyfill, Amanda; Wieser, Hannah-Marie N.; Reed, Evan C.; Redfield, Seth

    2016-01-01

    We present the abundances of neutron(n)-capture elements (atomic number Z > 30) and iron determined from deep optical echelle spectroscopy of 14 Galactic planetary nebulae (PNe). The spectra were obtained with the 2D-coudé spectrograph on the 2.7-m Harlan J. Smith telescope at McDonald Observatory. The abundances of n-capture elements can be enhanced in PNe due to slow n-capture nucleosynthesis in the progenitor asymptotic giant branch (AGB) stars. The high spectral resolution of these data (R = 36,700) allow most n-capture element emission lines to be resolved from other nebular and telluric features. We detect Kr in all of the observed PNe (with multiple ions detected in several objects), while Br, Rb, and Xe were each detected in 4--5 objects. Using the new Kr ionization correction factors (ICFs) of Sterling et al. (2015, ApJS, 218, 25), we find [Kr/O] abundances ranging from 0.05 to 1.1 dex. We utilize approximate ICFs for the other n-capture elements, and find slightly lower enrichments for Br and Rb (-0.1 to 0.7 dex), while Xe is enhanced relative to solar by factors of two to 30. The [Xe/Kr] ratios range from -0.3 to 1.4 dex, indicating a significant range in neutron exposures in PN progenitor stars. Interestingly, the largest [Xe/Kr] ratio is found in the thick-disk PN NGC 6644, which has a lower metallicity than the other observed PNe. We detect iron emission lines in all but one target. Fe can be depleted into dust grains in ionized nebulae, and its abundance thus provides key information regarding dust-to-gas ratios and grain destruction processes. We find that [Fe/O] ranges from -1.3 to -0.7 dex in the observed PNe, a smaller spread of depletion factors than found in recent studies (Delgado-Inglada & Rodriguez 2014, ApJ, 784, 173) though this may be due in part to our smaller sample. These data are part of a larger study of heavy elements in PNe, which will provide more accurate determinations of n-capture element abundances than previous estimates in several PNe, thereby providing key new constraints to models of AGB nucleosynthesis and Galactic chemical evolution. This work was supported by NSF awards AST-0708245 and AST-901432.

  1. Single-lens computed tomography imaging spectrometer and method of capturing spatial and spectral information

    NASA Technical Reports Server (NTRS)

    Wilson, Daniel W. (Inventor); Johnson, William R. (Inventor); Bearman, Gregory H. (Inventor)

    2011-01-01

    Computed tomography imaging spectrometers ("CTISs") employing a single lens are provided. The CTISs may be either transmissive or reflective, and the single lens is either configured to transmit and receive uncollimated light (in transmissive systems), or is configured to reflect and receive uncollimated light (in reflective systems). An exemplary transmissive CTIS includes a focal plane array detector, a single lens configured to transmit and receive uncollimated light, a two-dimensional grating, and a field stop aperture. An exemplary reflective CTIS includes a focal plane array detector, a single mirror configured to reflect and receive uncollimated light, a two-dimensional grating, and a field stop aperture.

  2. SPRED: a multichannel grazing-incidence spectrometer for plasma impurity diagnosis

    SciTech Connect

    Fonck, R.J.; Ramsey, A.T.; Yelle, R.V.

    1982-03-01

    A compact vacuum ultraviolet spectrometer system has been developed to provide time-resolved impurity spectra from tokamak plasmas. Two interchangeable aberration-corrected toroidal diffraction gratings with flat focal fields provide simultaneous coverage over the ranges 100 to 1100 A or 160 to 1700 A. The detector is an intensified self-scanning photodiode array. Spectral resolution is 2 A with the higher dispersion grating. Minimum readout time for a full spectrum is 20 ms, but up to 7 individual spectral lines can be measured with a 1 ms time resolution. The sensitivity of the system is comparable to that of a conventional grazing incidence monochromator.

  3. Application of imaging spectrometer in gas analysis by Raman scattering

    NASA Astrophysics Data System (ADS)

    Zuo, Duluo; Yu, Anlan; Li, Zhe; Wang, Xingbing; Xiong, Youhui

    2015-09-01

    Spontaneous Raman scattering is an effective technique in gas analysis, but the detection of minor constituents is difficult because of the low signal level and the usually existed background. Imaging spectrometer can provide highly spatial resolved spectra, so it should be much easier to pick up Raman signal of minor constituents from the Raman/fluorescence background of the sample cell and transporting optics compared with the widely used fiber-coupled spectrometers. For this reason, an imaging spectrometer was constructed from transmitting volume phase holographic grating, camera lenses and CCD detector. When it was used to analyze the gas sample in metal-lined capillary, which is a sample cell believed with great enhancement of Raman signal, the background was compressed obviously. When it was used to analyze the gas in a sample cell including a parabolic reflector, only weak background signal was observed, as the wide separation between the collecting zone (the focus point of the parabolic surface) and the wall of sample cell benefitted to the analysis by imaging spectrometer. By using the last sample cell, the signal from CO2 in ambient air was able to be found by an exposure time about 20 sec, and limits of detection for H2, CO2 and CO were estimated as 60 ppm, 100 ppm and 300 ppm respectively by the results of a longer exposure time. These results show that an imaging spectrometer paired with a well-arranged sample cell will lower the detecting limit effectively.

  4. Calibration facility for airborne imaging spectrometers

    NASA Astrophysics Data System (ADS)

    Gege, Peter; Fries, Jochen; Haschberger, Peter; Schtz, Paul; Schwarzer, Horst; Strobl, Peter; Suhr, Birgit; Ulbrich, Gerd; Jan Vreeling, Willem

    A new facility designed to perform calibration measurements of airborne imaging spectrometers was established at the German Aerospace Center (DLR) in Oberpfaffenhofen. This Calibration Home Base (CHB) is optimized to characterize radiometrically, spectrally, and geometrically the APEX (Airborne Prism Experiment) imaging spectrometer, which is currently being developed under the authority of the European Space Agency (ESA). It however can be used for other optical sensors as well. Computer control of major laboratory equipment allows automation of time consuming measurements. In APEX configuration (wavelength range: 380 to 2500 nm, instantaneous field of view: 0.48 mrad, field of view: 14 ?) spectral measurements can be performed to a wavelength uncertainty of 0.15 nm, geometric measurements at increments of 0.0017 mrad across track and 0.0076 mrad along track, and radiometric measurements to an uncertainty of 3% relative to national standard. The CHB can be adapted to similar sensors (including those with thermal infrared detectors) by exchanging the monochromator's lamp, the gratings and the filters, and by adjusting the distance between the sensor and folding mirror.

  5. Hadamard spectrometer for passive LWIR standoff surveillance

    NASA Astrophysics Data System (ADS)

    Kruzelecky, Roman V.; Wong, Brian; Zou, Jing; Mohammad, Najeeb; Jamroz, Wes; Soltani, Mohammed; Chaker, Mohamed; Haddad, Emile; Laou, Philips; Paradis, Suzanne

    2007-06-01

    Based on the principle of the Integrated Optical Spectrometer (IOSPEC), a waveguide-based, longwave infrared (LWIR) dispersive spectrometer with multiple input slits for Hadamard spectroscopy was designed and built intended for passive standoff chemical agent detection in 8 to 12μm spectral range. This prototype unit equips with a three-inch input telescope providing a field-of-view of 1.2 degrees, a 16-microslit array (each slit 60 μm by 1.8 mm) module for Hadamard binary coding, a 2-mm core ZnS/ZnSe/ZnS slab waveguide with a 2 by 2 mm2 optical input and micro-machined integrated optical output condensor, a Si micro-machined blazing grating, a customized 128-pixel LWIR mercury-cadmium-telluride (MCT) LN2 cooled detector array, proprietary signal processing technique, software and electronics. According to the current configuration, it was estimated that the total system weight to be ~4 kg, spectral resolution <4cm -1 and Noise Equivalent Spectral Radiance (NESR) <10 -8 Wcm -2 sr -1cm -1 in 8 to 12 μm. System design and preliminary test results of some components will be presented. Upon the arrival of the MCT detector array, the prototype unit will be further tested and its performance validated in fall of 2007.

  6. Spectrometer technology recommendations

    NASA Technical Reports Server (NTRS)

    Wilson, William J.

    1988-01-01

    A typical heterodyne remote sensing system contains three major elements: the antenna, the radiometer, and the spectrometer. The radiometer consists of the local oscillator, the mixer, and the intermediate frequency amplifiers. This subsystem performs the function of down converting the high frequency incident thermal emission signal to a lower intermediate frequency. The spectrometer measures the power spectrum of the down-converted signal simultaneously in many contiguous frequency channels. Typical spectrum analysis requirements involve measurement of signal bandwidths of 100 to 1000 MHz with a channel resolution of 0.5 to 10 MHz. Three general approaches are used for spectrometers: (1) filter banks, (2) Acousto-Optic Spectrometers (AOS's), and (3) digital autocorrelators. In contrast to the two frequency domain techniques, an autocorrelator works in the time domain. The autocorrelation function (ACF) of the incoming signal is computed and averaged over the integration time. The averaged ACF is then Fourier transformed to obtain the signal power spectrum. Significant progress was made in the development of sub mm antennas and radiometers. It is now time to begin research in the development of low power spaceborne spectrometers and to reduce their size and weight. The near-term research goal will be to develop a prototype digital autocorrelation spectrometer, using VLSI gate array technology, which will have a small size, low power requirements, and can be used in spacecraft mm and sub mm radiometer systems. The long-range objective of this technology development is to make extremely low power, less than 10 mW/channel, small and stable wideband spectrometers which can be used in future mm and sub mm wavelength space missions such as the Large Deployable Reflector.

  7. X-Ray Grating Spectroscopy of the T Tauri Star RY Tau

    NASA Astrophysics Data System (ADS)

    Skinner, Steve L.; Audard, Marc; Guedel, Manuel

    2016-01-01

    We present new results of X-ray observations of RY Tau, an accreting T Tauri star that drives a striking optically-revealed bipolar jet. We obtained sensitive X-ray grating observations with the Chandra High Energy Transmission Grating spectrometer (HETG) and the XMM-Newton Reflection Grating Spectrometer (RGS) in 2013-2014. These observations provide information on the temperature and emission measure distribution of the X-ray emitting plasma, a prerequisite for distinguishing between very hot plasma arising in magnetically-confined regions (e.g. the corona) and much cooler plasma that could originate in accretion shocks or the shocked jet. The emission measure distribution is dominated by hot plasma with a characteristic temperature T ~ 50 MK (kT ~ 4 - 5 keV), but higher temperatures were recorded during flares. Emission from the Fe K complex (Fe XXV; 6.7 keV) arising in very hot plasma was detected, as well as fluorescent Fe emission at 6.4 keV from cold surrounding material irradiated by the hard X-ray source. Spectral lines tracing cool plasma at temperatures of a few MK such as O VIII (0.654 keV) are also present in the RGS spectrum. We will summarize the X-ray spectral and variability properties of RY Tau and discuss possible origins of the cool plasma.

  8. Fabricating Radial Groove Gratings Using Projection Photolithography

    NASA Technical Reports Server (NTRS)

    Iazikov, Dmitri; Mossberg, Thomas W.

    2009-01-01

    Projection photolithography has been used as a fabrication method for radial grove gratings. Use of photolithographic method for diffraction grating fabrication represents the most significant breakthrough in grating technology in the last 60 years, since the introduction of holographic written gratings. Unlike traditional methods utilized for grating fabrication, this method has the advantage of producing complex diffractive groove contours that can be designed at pixel-by-pixel level, with pixel size currently at the level of 45 45 nm. Typical placement accuracy of the grating pixels is 10 nm over 30 nm. It is far superior to holographic, mechanically ruled or direct e-beam written gratings and results in high spatial coherence and low spectral cross-talk. Due to the smooth surface produced by reactive ion etch, such gratings have a low level of randomly scattered light. Also, due to high fidelity and good surface roughness, this method is ideally suited for fabrication of radial groove gratings. The projection mask is created using a laser writer. A single crystal silicon wafer is coated with photoresist, and then the projection mask, with its layer of photoresist, is exposed for patterning in a stepper or scanner. To develop the photoresist, the fabricator either removes the exposed areas (positive resist) of the unexposed areas (negative resist). Next, the patterned and developed photoresist silicon substrate is subjected to reactive ion etching. After this step, the substrate is cleaned. The projection mask is fabricated according to electronic design files that may be generated in GDS file format using any suitable CAD (computer-aided design) or other software program. Radial groove gratings in off-axis grazing angle of incidence mount are of special interest for x-ray spectroscopy, as they allow achieving higher spectral resolution for the same grating area and have lower alignment tolerances than traditional in-plane grating scheme. This is especially critical for NASA Constellation- X project that will utilize hundreds of gratings all of which need to be precisely aligned for x-ray observation of space.

  9. 1-m normal incidence UV spectrometer for plasma measurements

    SciTech Connect

    Register, D.F.; Jackson, G.L.; Walker, S.E.

    1985-05-01

    An Acton Research VM 521-SG UV monochromator has been equipped with an intensified diode array detector for use as a mid-UV spectrometer. 600 and 2400 gr/mm gratings are used in a turret assembly for either low-resolution surveys or high-resolution Doppler ion studies. The detector is a CsI coated MCP with a P-11 output phosphor. The 1024 diode array is scanned at a 1-MHZ video rate allowing a complete spectra to be obtained in 1.0 ms. System performance and preliminary operation on the OHTE plasma will be presented.

  10. A miniture spectrometer using color CCD and frame calculus technique

    NASA Astrophysics Data System (ADS)

    Wan, Wei; Zhang, Guoping; Chen, Minghong; Liu, Minmin

    2005-01-01

    A design of spectrometer is presented, which uses a holographic grating and a two-dimensional color CCD camera connected with PC via video format port. And in the image post-procession, a real-time frame calculus technique and a non-linear filter were applied to provider higher image quality and better resistant to background noise. With improved designed zoom mechanics, the device has a wide resolution dynamic range and high frequency, since it can gather more spectrum information than linear black-white CCD. The spectrum analysis experiments for water quality detection indicate that the device can meet variant requirements of analysis at low cost.

  11. Diffraction Grating Structures in Solar Cells

    SciTech Connect

    ZAIDI,SALEEM H.; GEE,JAMES M.; RUBY,DOUGLAS S.

    2000-12-01

    Sub-wavelength periodic texturing (gratings) of crystalline-silicon (c-Si) surfaces for solar cell applications can be designed for maximizing optical absorption in thin c-Si films. We have investigated c-Si grating structures using rigorous modeling, hemispherical reflectance, and internal quantum efficiency measurements. Model calculations predict almost {approximately}100% energy coupling into obliquely propagating diffraction orders. By fabrication and optical characterization of a wide range of 1D & 2D c-Si grating structures, we have achieved broad-band, low ({approximately} 5%) reflectance without an anti-reflection film. By integrating grating structures into conventional solar cell designs, we have demonstrated short-circuit current density enhancements of 3.4 and 4.1 mA/cm{sup 2} for rectangular and triangular 1D grating structures compared to planar controls. The effective path length enhancements due to these gratings were 2.2 and 1.7, respectively. Optimized 2D gratings are expected to have even better performance.

  12. Mixed metal dielectric pulse compression gratings

    NASA Astrophysics Data System (ADS)

    Nauport, J.; Bonod, N.; Hocquet, S.; Palmier, S.; Lavastre, E.; Baclet, N.; Dupuy, G.

    2010-11-01

    A Petawatt facility called PETAL (PETawatt Aquitaine Laser) is under development near the LIL (Ligne d'Integration Laser) at CEA Cesta, France. PETAL facility uses chirped pulse amplification (CPA) technique. This system needs large pulse compression grating exhibiting damage threshold of more than 4 J/cm2 normal beam at 1.053?m and for 500fs pulses. In this paper, we study an alternative design to the classic multilayer dielectric (MLD) grating called "mixed metal-multilayer dielectric grating" (MMLD). This design consists in a gold reflective layer coated with a few pairs of HfO2/SiO2. The top low index SiO2 layer of the stack is then engraved to receive the grating. We evidenced in a previous work that leads to high efficient pulse compression gratings. We have shown in last Boulder Damage Symposium that mixed mirror is equivalent to a "classic" MLD mirror. We herein detail the damage performances obtained on the MMLD gratings and compare them with these of MLD gratings.

  13. Soft x-ray transmission gratings

    SciTech Connect

    Arakawa, E.T.; Caldwell, P.J.; Williams, M.W.

    1980-01-01

    A technique was developed for producing transmission diffraction gratings suitable for use in the soft x-ray region. Thin self-supporting films of a transparent material are overlaid with several thousand opaque metallic strips per mm. Gratings with 2100, 2400, and 5600 1/mm have been produced and tested. Representative spectra over the wavelength range from 17.2 to 40.0 nm are given for a grating consisting of a 120-nm-thick Al support layer overlaid with 2400, 34-nm-thick, Ag strips/mm. The absolute transmittance is approx. 13% at 30 nm, and the efficiency in the first order is approx. 16%. The observed resolution of approx. 2A is acceptable for many of the potential applications. These gratings have several advantages over the two presently available alternatives in the soft x-ray region (i.e., reflection gratings used at grazing incidence and free-standing metallic wire transmission gratings). Fabrication is relatively quick, simple, and cheap. The support layer can also serve as a filter and help conduct excessive heat away. Higher line densities and hence higher resolutions are possible, and when used at normal incidence the spectra are aberration free. Suitable materials, component thicknesses, and line densities can be chosen to produce a grating of optimum characteristics for a particular application.

  14. Schlmilch series and grating sums

    NASA Astrophysics Data System (ADS)

    McPhedran, R. C.; Nicorovici, N. A.; Botten, L. C.

    2005-09-01

    We consider sums over the set of positive integers relevant to construction of periodic Green's functions for diffraction gratings and similar problems, and provide a general formula for a combination of Bessel functions of complex order and complex powers of distance from the origin. This general formula is investigated in a number of particular cases, and in particular we provide expressions which enable sums of functions with Neumann series to be re-expressed as combinations of hypergeometric series. We also investigate sums of Neumann functions of integer order, using analytic continuation techniques to provide formulae for their evaluation which we demonstrate are accurate and efficient in both the high and low frequency regions. We also exhibit sums which may be evaluated analytically, and recurrence formulae linking sums.

  15. Absorbing polarization selective resonant gratings.

    PubMed

    Lehmuskero, Anni; Vartiainen, Ismo; Saastamoinen, Toni; Alasaarela, Tapani; Kuittinen, Markku

    2010-12-20

    We introduce resonant absorbers that consist of linear metal wires embedded inside of a titanium dioxide grating. We show that in these structures the guided-mode resonance may lead to the almost total absorption of one polarization component and greatly enhance the absorption in localized surface plasma resonance. In addition, we show that the structures have potential to function as filters or polarizing beamsplitters. Absorption of 99.67 % has been obtained together with the contrast of 6600 at the wavelength of 532 nm. This corresponds the extinction of 8.8597. The results have been verified experimentally by fabricating an absorbing filter with electron beam lithography and atomic layer deposition technique. The absorption is remarkably high considering the thickness of the structures which is only 219-333 nm. PMID:21197005

  16. Electron-proton spectrometer

    NASA Technical Reports Server (NTRS)

    Winckler, J. R.

    1973-01-01

    An electron-proton spectrometer was designed to measure the geomagnetically trapped radiation in a geostationary orbit at 6.6 earth radii in the outer radiation belt. This instrument is to be flown on the Applications Technology Satellite-F (ATS-F). The electron-proton spectrometer consists of two permanent magnet surface barrier detector arrays and associated electronics capable of selecting and detecting electrons in three energy ranges: (1) 30-50 keV, (2) 150-200 keV, and (3) 500 keV and protons in three energy ranges. The electron-proton spectrometer has the capability of measuring the fluxes of electrons and protons in various directions with respect to the magnetic field lines running through the satellite. One magnet detector array system is implemented to scan between EME north and south through west, sampling the directional flux in 15 steps. The other magnet-detector array system is fixed looking toward EME east.

  17. Phasor Analysis of Binary Diffraction Gratings with Different Fill Factors

    ERIC Educational Resources Information Center

    Martinez, Antonio; Sanchez-Lopez, Ma del Mar; Moreno, Ignacio

    2007-01-01

    In this work, we present a simple analysis of binary diffraction gratings with different slit widths relative to the grating period. The analysis is based on a simple phasor technique directly derived from the Huygens principle. By introducing a slit phasor and a grating phasor, the intensity of the diffracted orders and the grating's resolving

  18. Shuttle imaging spectrometer optics

    NASA Technical Reports Server (NTRS)

    Page, N. A.; Smith, S. T.; Sepulveda, C. A.; White, M. L.

    1987-01-01

    This paper discusses the optical design and performance of the Shuttle Imaging Spectrometer (SISEX) optical system, which is being planned for the next generation of Earth remote sensing instruments. This optical system represents a new approach to remote sensing in which wide-field optics, dispersing elements, and area detector arrays are used in place of mechanical scanners, filters, and discrete detector elements or linear arrays. While the SISEX optical system is designed specifically for flight on Shuttle, the same optical approach is being used in the design of other remote sensing instruments, such as the High Resolution Imaging Spectrometer, which is expected to fly on the Earth Observing System.

  19. The Apollo Alpha Spectrometer.

    NASA Technical Reports Server (NTRS)

    Jagoda, N.; Kubierschky, K.; Frank, R.; Carroll, J.

    1973-01-01

    Located in the Science Instrument Module of Apollo 15 and 16, the Alpha Particle Spectrometer was designed to detect and measure the energy of alpha particles emitted by the radon isotopes and their daughter products. The spectrometer sensor consisted of an array of totally depleted silicon surface barrier detectors. Biased amplifier and linear gate techniques were utilized to reduce resolution degradation, thereby permitting the use of a single 512 channel PHA. Sensor identification and in-flight radioactive calibration were incorporated to enhance data reduction.

  20. Broad band waveguide spectrometer

    DOEpatents

    Goldman, Don S. (Folsom, CA)

    1995-01-01

    A spectrometer for analyzing a sample of material utilizing a broad band source of electromagnetic radiation and a detector. The spectrometer employs a waveguide possessing an entry and an exit for the electromagnetic radiation emanating from the source. The waveguide further includes a surface between the entry and exit portions which permits interaction between the electromagnetic radiation passing through the wave guide and a sample material. A tapered portion forms a part of the entry of the wave guide and couples the electromagnetic radiation emanating from the source to the waveguide. The electromagnetic radiation passing from the exit of the waveguide is captured and directed to a detector for analysis.

  1. Sensitive visual test for concave diffraction gratings.

    NASA Technical Reports Server (NTRS)

    Bruner, E. C., Jr.

    1972-01-01

    A simple visual test for the evaluation of concave diffraction gratings is described. It is twice as sensitive as the Foucault knife edge test, from which it is derived, and has the advantage that the images are straight and free of astigmatism. It is particularly useful for grating with high ruling frequency where the above image faults limit the utility of the Foucault test. The test can be interpreted quantitatively and can detect zonal grating space errors of as little as 0.1 A.

  2. Regeneration of fiber Bragg gratings under strain.

    PubMed

    Wang, Tao; Shao, Li-Yang; Canning, John; Cook, Kevin

    2013-04-01

    The effect of strain on both the index modulation, Δn(mod), and average index, Δn, during grating regeneration within two types of fibers is studied. Significant tunability of the Bragg wavelength (λ(B)>48 nm) is observed during postannealing at or above the strain temperature of the glass. The main reason for the grating wavelength shift during annealing with load is the elongation of the fiber. As well, the observed Moiré interference cycling through regeneration indicates the presence of two gratings. PMID:23545963

  3. Aberrations of holographic toroidal grating systems

    NASA Technical Reports Server (NTRS)

    Chrisp, M. P.

    1983-01-01

    Expressions are derived for the sixteen wave front aberration coefficients of a single grating. These give the wave aberrations to the fourth order for a plane symmetric grating system. The contributions from each mirror and grating can be added to give the aberrations in the final image. Problems encountered with intermediate astigmatic images are overcome by defining the wave front aberration with respect to an astigmatic reference surface. There is one field variable describing displacement of the object point from the symmetry plane. The aperture stop may be placed anywhere in the system, and equations are given for the aberration changes produced by sifting this position.

  4. Diffraction by m-bonacci gratings

    NASA Astrophysics Data System (ADS)

    Monsoriu, Juan A.; Gimnez, Marcos H.; Furlan, Walter D.; Barreiro, Juan C.; Saavedra, Genaro

    2015-11-01

    We present a simple diffraction experiment with m-bonacci gratings as a new interesting generalization of the Fibonacci ones. Diffraction by these non-conventional structures is proposed as a motivational strategy to introduce students to basic research activities. The Fraunhofer diffraction patterns are obtained with the standard equipment present in most undergraduate physics labs and are compared with those obtained with regular periodic gratings. We show that m-bonacci gratings produce discrete Fraunhofer patterns characterized by a set of diffraction peaks which positions are related to the concept of a generalized golden mean. A very good agreement is obtained between experimental and numerical results and the students feedback is discussed.

  5. Aplanatic and quasi-aplanatic diffraction gratings

    DOEpatents

    Hettrick, Michael C. (Berkeley, CA)

    1989-01-01

    A reflection diffraction grating having a series of transverse minute grooves of progressively varying spacing along a concave surface enables use of such gratings for X-ray or longer wavelength imaging of objects. The variable groove spacing establishes aplanatism or substantially uniform magnification across the optical aperture. The grating may be used, for example, in X-ray microscopes or telescopes of the imaging type and in X-ray microprobes. Increased spatial resolution and field of view may be realized in X-ray imaging.

  6. Aplanatic and quasi-aplanatic diffraction gratings

    DOEpatents

    Hettrick, M.C.

    1987-09-14

    A reflection diffraction grating having a series of transverse minute grooves of progressively varying spacing along a concave surface enables use of such gratings for x-ray or longer wavelength imaging of objects. The variable groove spacing establishes aplanatism or substantially uniform magnetification across the optical aperture. The grating may be sued, for example, in x-ray microscopes or telescopes of the imaging type and in x-ray microprobed. Increased spatial resolution and field of view may be realized in x-ray imaging. 5 figs.

  7. Fiber Bragg Grating Sensors for Harsh Environments

    PubMed Central

    Mihailov, Stephen J.

    2012-01-01

    Because of their small size, passive nature, immunity to electromagnetic interference, and capability to directly measure physical parameters such as temperature and strain, fiber Bragg grating sensors have developed beyond a laboratory curiosity and are becoming a mainstream sensing technology. Recently, high temperature stable gratings based on regeneration techniques and femtosecond infrared laser processing have shown promise for use in extreme environments such as high temperature, pressure or ionizing radiation. Such gratings are ideally suited for energy production applications where there is a requirement for advanced energy system instrumentation and controls that are operable in harsh environments. This paper will present a review of some of the more recent developments. PMID:22438744

  8. Analysis and System Design Framework for Infrared Spatial Heterodyne Spectrometers

    SciTech Connect

    Cooke, B.J.; Smith, B.W.; Laubscher, B.E.; Villeneuve, P.V.; Briles, S.D.

    1999-04-05

    The authors present a preliminary analysis and design framework developed for the evaluation and optimization of infrared, Imaging Spatial Heterodyne Spectrometer (SHS) electro-optic systems. Commensurate with conventional interferometric spectrometers, SHS modeling requires an integrated analysis environment for rigorous evaluation of system error propagation due to detection process, detection noise, system motion, retrieval algorithm and calibration algorithm. The analysis tools provide for optimization of critical system parameters and components including : (1) optical aperture, f-number, and spectral transmission, (2) SHS interferometer grating and Littrow parameters, and (3) image plane requirements as well as cold shield, optical filtering, and focal-plane dimensions, pixel dimensions and quantum efficiency, (4) SHS spatial and temporal sampling parameters, and (5) retrieval and calibration algorithm issues.

  9. Tunable External Cavity Quantum Cascade Lasers (EC-QCL): an application field for MOEMS based scanning gratings

    NASA Astrophysics Data System (ADS)

    Grahmann, Jan; Merten, André; Ostendorf, Ralf; Fontenot, Michael; Bleh, Daniela; Schenk, Harald; Wagner, Hans-Joachim

    2014-03-01

    In situ process information in the chemical, pharmaceutical or food industry as well as emission monitoring, sensitive trace detection and biological sensing applications would increasingly rely on MIR-spectroscopic anal­ysis in the 3 μm - 12 μm wavelength range. However, cost effective, portable, low power consuming and fast spectrometers with a wide tuning range are not available so far. To provide these MIR-spectrometer properties, the combination of quantum cascade lasers with a MOEMS scanning grating as wavelength selective element in the external cavity is addressed to provide a very compact and fast tunable laser source for spectroscopic analysis.

  10. Design and fabrication of a MEMS high-efficiency NIR-scanning grating based on tilted (1 1 1) silicon wafer

    NASA Astrophysics Data System (ADS)

    Nie, Qiuyu; Wen, Zhiyu; Huang, Jian

    2015-10-01

    A MEMS high-efficiency scanning grating for near infrared micro spectrometers has been successfully developed. This paper presents its design, fabrication, and measurement results. Compared with previously reported rectangular and V-shaped groove grating scanners, the presented blazed grating scanner - in which the blazed grating can be obtained by wet anisotropic etching a tilted (1 1 1) silicon substrate, and the desired blaze angle can be easily realized by choosing the appropriate tilt angle of device silicon - has the potential to scan at higher diffraction efficiency. Moreover, an electromagnetic angle sensor is designed to detect the state of the scanning grating and supply the feedback signal for close loop control. We have demonstrated a prototype with grating constants of 4 ?m and blazed angle of 7.54. Experimental results have showed that the diffraction efficiencies of the -1st order can reach 70% at the wavelength of 1392 nm. The output voltages of angle sensor have a good linear relationship with optical scan angle of the grating scanner, and the sensitivity of the angle sensor is 0.54 mV/ without amplifying.

  11. Arcus: The next generation of high-resolution X-ray grating spectra

    NASA Astrophysics Data System (ADS)

    Smith, Randall

    2014-11-01

    We present the design and scientific motivation for Arcus, an X-ray grating spectrometer mission to be deployed on the International Space Station. This mission will observe structure formation at and beyond the edges of clusters and galaxies, feedback from supermassive black holes, the structure of the interstellar medium and the formation and evolution of stars. Key mission requirements will be R>2500 and >600 cm^2 of effective area at the crucial O VII and O VIII lines, with the full bandpass going from 8-52, with an overall minimum resolution of 1300 and effective area >150 cm^2. We will use the silicon pore optics proposed for ESA's Athena mission, paired with off-plane gratings being developed at the University of Iowa and combined with MIT/Lincoln Labs CCDs.

  12. On-chip broadband spectral filtering using planar double high-contrast grating reflectors

    NASA Astrophysics Data System (ADS)

    Horie, Yu; Arbabi, Amir; Faraon, Andrei

    2015-02-01

    We propose a broadband free-space on-chip spectrometer based on an array of integrated narrowband filters consisting of Fabry-Perot resonators formed by two high-contrast grating (HCG) based reflectors separated by a low-index thin layer with a fixed cavity thickness. Using numerical simulations, broadband tunability of resonance wavelengths was achieved only by changing the in-plane grating parameters such as period or duty cycle of HCGs while the substrate geometry was kept fixed. Experimentally, the HCG reflectors were fabricated on silicon on insulator (SOI) substrates and high reflectivity was measured, fabrication process for the proposed double HCG-based narrowband filter array was developed. The filtering function that can be spanned over a wide range of wavelengths was measured.

  13. The development and test of a deformable diffraction grating for a stigmatic EUV spectroheliometer

    NASA Technical Reports Server (NTRS)

    Timothy, J. Gethyn; Walker, A. B. C., Jr.; Morgan, J. S.; Huber, M. C. E.; Tondello, G.

    1992-01-01

    The objectives were to address currently unanswered fundamental questions concerning the fine scale structure of the chromosphere, transition region, and corona. The unique characteristics of the spectroheliometer was used in combination with plasma diagnostic techniques to study the temperature, density, and velocity structures of specific features in the solar outer atmosphere. A unified understanding was sought of the interplay between the time dependent geometry of the magnetic field structure and the associated flows of mass and energy, the key to which lies in the smallest spatial scales that are unobservable with current EUV instruments. Toroidal diffraction gratings were fabricated and tested by a new technique using an elastically deformable substrate. The toroidal diffraction gratings was procured and tested to be used for the evaluation of the Multi-Anode Microchannel Array (MAMA) detector systems for the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) and UV Coronagraph Spectrometer (UVCS) instruments on the SOHO mission.

  14. Boosting phase contrast with a grating Bonse-Hart interferometer of 200 nanometre grating period.

    PubMed

    Wen, Han; Gomella, Andrew A; Patel, Ajay; Wolfe, Douglas E; Lynch, Susanna K; Xiao, Xianghui; Morgan, Nicole

    2014-03-01

    We report on a grating Bonse-Hart interferometer for phase-contrast imaging with hard X-rays. The method overcomes limitations in the level of sensitivity that can be achieved with the well-known Talbot grating interferometer, and without the stringent spectral filtering at any given incident angle imposed by the classic Bonse-Hart interferometer. The device operates in the far-field regime, where an incident beam is split by a diffraction grating into two widely separated beams, which are redirected by a second diffraction grating to merge at a third grating, where they coherently interfere. The wide separation of the interfering beams results in large phase contrast, and in some cases absolute phase images are obtained. Imaging experiments were performed using diffraction gratings of 200 nm period, at 22.5 keV and 1.5% spectral bandwidth on a bending-magnetic beamline. Novel design and fabrication process were used to achieve the small grating period. Using a slitted incident beam, we acquired absolute and differential phase images of lightly absorbing samples. An advantage of this method is that it uses only phase modulating gratings, which are easier to fabricate than absorption gratings of the same periods. PMID:24470412

  15. Boosting phase contrast with a grating Bonse–Hart interferometer of 200 nanometre grating period

    PubMed Central

    Wen, Han; Gomella, Andrew A.; Patel, Ajay; Wolfe, Douglas E.; Lynch, Susanna K.; Xiao, Xianghui; Morgan, Nicole

    2014-01-01

    We report on a grating Bonse–Hart interferometer for phase-contrast imaging with hard X-rays. The method overcomes limitations in the level of sensitivity that can be achieved with the well-known Talbot grating interferometer, and without the stringent spectral filtering at any given incident angle imposed by the classic Bonse–Hart interferometer. The device operates in the far-field regime, where an incident beam is split by a diffraction grating into two widely separated beams, which are redirected by a second diffraction grating to merge at a third grating, where they coherently interfere. The wide separation of the interfering beams results in large phase contrast, and in some cases absolute phase images are obtained. Imaging experiments were performed using diffraction gratings of 200 nm period, at 22.5 keV and 1.5% spectral bandwidth on a bending-magnetic beamline. Novel design and fabrication process were used to achieve the small grating period. Using a slitted incident beam, we acquired absolute and differential phase images of lightly absorbing samples. An advantage of this method is that it uses only phase modulating gratings, which are easier to fabricate than absorption gratings of the same periods. PMID:24470412

  16. Cyclotrons as mass spectrometers

    SciTech Connect

    Clark, D.J.

    1984-04-01

    The principles and design choices for cyclotrons as mass spectrometers are described. They are illustrated by examples of cyclotrons developed by various groups for this purpose. The use of present high energy cyclotrons for mass spectrometry is also described. 28 references, 12 figures.

  17. Experience with spreader/travelling grate combustion

    SciTech Connect

    Schroth, G. )

    1990-01-01

    Travelling grate spreader stokers were not very popular in the Federal Republic of Germany, since for grate firings classified bituminous coals were in unlimited and inexpensive supply which could be burnt successfully on grates with hopper feeding. The steam generator outputs were varying between 1o and 28 kg/s (40 - 100 t/h). Due to the increased supply of unclassified bituminous coals with higher fine grain portions - mainly imported coals - on the market and required steam generator outputs greater than 28 kg/s the travelling grate firing with spreader stokers became attractive and necessary. As an example of the steam generator with 41.6 kg/s the plant set-up and operational experiences shall be described in the following. This plant has been constructed in a thermal power station in the South of Germany as an auxiliary steam generator for 740 MW unit fired with pulverized bituminous coal and for remote heating supply.

  18. Liquid crystal on subwavelength metal gratings

    SciTech Connect

    Palto, S. P.; Barnik, M. I.; Artemov, V. V.; Shtykov, N. M.; Geivandov, A. R.; Yudin, S. G.; Gorkunov, M. V.

    2015-06-14

    Optical and electrooptical properties of a system consisting of subwavelength metal gratings and nematic liquid crystal layer are studied. Aluminium gratings that also act as interdigitated electrodes are produced by focused ion beam lithography. It is found that a liquid crystal layer strongly influences both the resonance and light polarization properties characteristic of the gratings. Enhanced transmittance is observed not only for the TM-polarized light in the near infrared spectral range but also for the TE-polarized light in the visible range. Although the electrodes are separated by nanosized slits, and the electric field is strongly localized near the surface, a pronounced electrooptical effect is registered. The effect is explained in terms of local reorientation of liquid crystal molecules at the grating surface and propagation of the orientational deformation from the surface into the bulk of the liquid crystal layer.

  19. Multiperiod-grating surface-emitting lasers

    NASA Technical Reports Server (NTRS)

    Lang, Robert J. (Inventor)

    1992-01-01

    Surface-emitting distributed feedback (DFB) lasers are disclosed with hybrid gratings. A first-order grating is provided at one or both ends of the active region of the laser for retroreflection of light back into the active region, and a second-order or nonresonant grating is provided at the opposite end for coupling light out perpendicular to the surfaces of the laser or in some other selected direction. The gratings may be curved to focus light retroreflected into the active region and to focus light coupled out to a point. When so focused to a point, the DFB laser may be part of a monolithic read head for a laser recorded disk, or an optical coupler into an optical fiber.

  20. Electromagnetic diffraction by plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Bocker, R. P.; Marathay, A. S.

    1972-01-01

    A plane wave theory was developed to study electromagnetic diffraction by plane reflection diffraction gratings of infinite extent. A computer program was written to calculate the energy distribution in the various orders of diffraction for the cases when the electric or magnetic field vectors are parallel to the grating grooves. Within the region of validity of this theory, results were in excellent agreement with those in the literature. Energy conservation checks were also made to determine the region of validity of the plane wave theory. The computer program was flexible enough to analyze any grating profile that could be described by a single value function f(x). Within the region of validity the program could be used with confidence. The computer program was used to investigate the polarization and blaze properties of the diffraction grating.

  1. Grating based plasmonic band gap cavities.

    PubMed

    Senlik, S Seckin; Kocabas, Askin; Aydinli, Atilla

    2009-08-31

    We report on a comparative study of grating based plasmonic band gap cavities. Numerically, we calculate the quality factors of the cavities based on three types of grating surfaces; uniform, biharmonic and Moir surfaces. We show that for biharmonic band gap cavities, the radiation loss can be suppressed by removing the additional grating component in the cavity region. Due to the gradual change of the surface profile in the cavity region, Moir type surfaces support cavity modes with higher quality factors. Experimentally, we demonstrate the existence of plasmonic cavities based on uniform gratings. Effective index perturbation and cavity geometries are obtained by additional dielectric loading. Quality factor of 85 is obtained from the measured band structure of the cavity. PMID:19724552

  2. Hydraulic Capacity of an ADA Compliant Street Drain Grate

    SciTech Connect

    Lottes, Steven A.; Bojanowski, Cezary

    2015-09-01

    Resurfacing of urban roads with concurrent repairs and replacement of sections of curb and sidewalk may require pedestrian ramps that are compliant with the American Disabilities Act (ADA), and when street drains are in close proximity to the walkway, ADA compliant street grates may also be required. The Minnesota Department of Transportation ADA Operations Unit identified a foundry with an available grate that meets ADA requirements. Argonne National Laboratory’s Transportation Research and Analysis Computing Center used full scale three dimensional computational fluid dynamics to determine the performance of the ADA compliant grate and compared it to that of a standard vane grate. Analysis of a parametric set of cases was carried out, including variation in longitudinal, gutter, and cross street slopes and the water spread from the curb. The performance of the grates was characterized by the fraction of the total volume flow approaching the grate from the upstream that was captured by the grate and diverted into the catch basin. The fraction of the total flow entering over the grate from the side and the fraction of flow directly over a grate diverted into the catch basin were also quantities of interest that aid in understanding the differences in performance of the grates. The ADA compliant grate performance lagged that of the vane grate, increasingly so as upstream Reynolds number increased. The major factor leading to the performance difference between the two grates was the fraction of flow directly over the grates that is captured by the grates.

  3. Grating enhanced solid-state laser amplifiers

    DOEpatents

    Erlandson, Alvin C.; Britten, Jerald A.

    2010-11-09

    A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. Such an invention, as disclosed herein, uses diffraction gratings to increase gain, stored energy density, and pumping efficiency of solid-state laser gain media, such as, but not limited to rods, disks and slabs. By coupling predetermined gratings to solid-state gain media, such as crystal or ceramic laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.

  4. Spatial heterodyne interferometry with polarization gratings.

    PubMed

    Kudenov, Michael W; Miskiewicz, Matthew N; Escuti, Michael J; Dereniak, Eustace L

    2012-11-01

    The implementation of a polarization-based spatial heterodyne interferometer (SHI) is described. While a conventional SHI uses a Michelson interferometer and diffraction gratings, our SHI exploits mechanically robust Wollaston prisms and polarization gratings. A theoretical model for the polarization SHI is provided and validated with data from our proof of concept experiments. This device is expected to provide a compact monolithic sensor for subangstrom resolution spectroscopy in remote sensing, biomedical imaging, and machine vision applications. PMID:23114313

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  8. Analysis of grating surface emitting lasers

    SciTech Connect

    Noll, R.J.; Macomber, S.H. )

    1990-05-01

    A new approach to the analysis of grating-coupled semiconductor lasers is presented. The authors show that there are only two resonant solutions when the grating has infinite extent. The solutions are either symmetric or antisymmetric about the center of the longitudinal coordinate system where the antisymmetric solution is nonradiating. The field in the grating layer is expressed in terms of grating eigenfunctions and rigorously matched to the boundary conditions at the waveguide interface. Solutions to the finite length grating problem are expressed as linear combinations of the infinite length solution. The authors show that the two diffraction parameters in the coupled-wave equations are composed of sums and differences of the eigenvalues from the infinite length problem. In particular, they consider structures with symmetric second order gratings composed of gold. The surface emission coefficient is shown to be very large whereas the absorption loss in the gold is small. The slope efficiency of finite length distributed feedback lasers is found to be a strong function of stripe length.

  9. Optical system design for a short-wave infrared imaging spectrometer

    NASA Astrophysics Data System (ADS)

    Huang, Han; Li, Xiaotong; Cen, Zhaofeng

    2012-11-01

    A short-wave infrared (SWIR) imaging spectrometer with all reflective elements was designed, covering the spectral range 1000-2500nm with a spectral resolution of 10nm. The imaging spectrometer is composed of an off-axis three-mirror anastigmatic (TMA) telescope and an Offner spectral imaging system with convex grating. The design result shows that the system has compact structure, light weight, wide field of view, small smile and keystone, excellent image quality and practical feasibility. The design method is simple and easy-operating.

  10. Elemental abundance analyses with Complejo Astronomico El Leoncito REOSC echelle spectrograms. IV. Extensions of nine previous analyses

    NASA Astrophysics Data System (ADS)

    Adelman, S. J.; Pintado, O. I.

    2000-02-01

    Using new CASLEO echelle spectrograms, we extended our elemental abundances of the sharp-lined Mercury-Manganese stars mu Lep, 14 Hya, kappa Cnc, HR 4487, HR 4817, 28 Her, and HR 7245, the closely related star 3 Cen A, and 7 Sex an A0 V star with Population I abundances, but with Population II star space motions. The lambda lambda 4500-6200 region contains a sufficient number of lines to derive high-quality abundances of these stars. For most stars, the new spectra provide additional lines for the analyses which improve their quality as well as help fill in the periodic table. Table~5 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsweb.u-strabg.fr/Abstract.html}

  11. Simulation of the SAGE spectrometer

    NASA Astrophysics Data System (ADS)

    Cox, D. M.; Konki, J.; Greenlees, P. T.; Hauschild, K.; Herzberg, R.-D.; Pakarinen, J.; Papadakis, P.; Rahkila, P.; Sandzelius, M.; Sorri, J.

    2015-06-01

    The SAGE spectrometer combines a Ge-detector array with a Si detector to allow simultaneous detection of γ-rays and electrons. A comprehensive GEANT4 simulation package of the SAGE spectrometer has been developed with the ability to simulate the expected datasets based on user input files. The measured performance of the spectrometer is compared to the results obtained from the simulations.

  12. Tropospheric and Airborne Emission Spectrometers

    NASA Technical Reports Server (NTRS)

    Glavich, Thomas; Beer, Reinhard

    1996-01-01

    X This paper describes the development of two related instruments, the Tropospheric Emission Spectrometer (TES) and the Airborne Emission Spectrometer (AES). Both instruments are infrared imaging Fourier Transform Spectrometers, used for measuring the state of the lower atmosphere, and in particular the measurement of ozone and ozone sources and sinks.

  13. Astigmatism-corrected Czerny-Turner imaging spectrometer for broadband spectral simultaneity

    SciTech Connect

    Xue Qingsheng

    2011-04-01

    A low-cost, broadband, astigmatism-corrected Czerny-Turner arrangement with a fixed plane grating is proposed. A wedge cylindrical lens is used to correct astigmatism over a broadband spectral range. The principle and method of astigmatism correction are described in detail. We compare the performance of this modified Czerny-Turner arrangement with that of the traditional Czerny-Turner arrangement by using a practical Czerny-Turner imaging spectrometer example.

  14. Aberration-corrected Czerny-Turner imaging spectrometer with a wide spectral region

    SciTech Connect

    Xue Qingsheng; Wang Shurong; Lu Fengqin

    2009-01-01

    A modified asymmetrical Czerny-Turner arrangement with a fixed plane grating is proposed to correct aberrations over a wide spectral region by analysis of the dependence of aberration correction for different wavelengths. The principle and method of aberration correction are described in detail. We compare the performance of this modified Czerny-Turner arrangement with that of the existing Czerny-Turner arrangement by using a practical Czerny-Turner imaging spectrometer example.

  15. FAST NEUTRON SPECTROMETER

    DOEpatents

    Davis, F.J.; Hurst, G.S.; Reinhardt, P.W.

    1959-08-18

    An improved proton recoil spectrometer for determining the energy spectrum of a fast neutron beam is described. Instead of discriminating against and thereby"throwing away" the many recoil protons other than those traveling parallel to the neutron beam axis as do conventional spectrometers, this device utilizes protons scattered over a very wide solid angle. An ovoidal gas-filled recoil chamber is coated on the inside with a scintillator. The ovoidal shape of the sensitive portion of the wall defining the chamber conforms to the envelope of the range of the proton recoils from the radiator disposed within the chamber. A photomultiplier monitors the output of the scintillator, and a counter counts the pulses caused by protons of energy just sufficient to reach the scintillator.

  16. Alpha Magnetic Spectrometer

    NASA Astrophysics Data System (ADS)

    Ting, Samuel

    2012-07-01

    The Alpha Magnetic Spectrometer (AMS) is a precision particle physics magnetic spectrometer designed to measure electrons, positrons, gamma rays and various nuclei and anti-nuclei from the cosmos up to TeV energy ranges. AMS weighs 7.5 tons and measures 5 meters by 4 meters by 3 meters. It contains 300,000 channels of electronics and 650 onboard microprocessors. It was delivered to the International Space Station onboard space shuttle Endeavour and installed on May 19, 2011. Since that time, more than 14 billion cosmic ray events have been collected. All the detectors function properly. At this moment, we are actively engaged in data analysis. AMS is an international collaboration involving 16 countries and 60 institutes. It took 16 years to construct and test. AMS is the only major physical science experiment on the International Space Station and will continue to collect data over the entire lifetime of the Space Station (10-20 years).

  17. Grille spectrometer (grille)

    NASA Technical Reports Server (NTRS)

    Ackerman, M.; Besson, J.

    1988-01-01

    The Grille spectrometer was designed and flown on Spaceklab 1 by two organizations: The Office National d'Etudes et de Recherches Aerospatiales in France and the Belgian Institute for Space Aeronomy in Belgium. Its purpose is to study, on a global scale, atmospheric parameters between 15 and 150 km altitude. The investigation uses high-resolution (better than 0.1/cm) spectroscopic observations of the earth's limb in the wavelength range characteristic of the vibrational-rotational lines of the relevant atmospheric constituents. Characteristics and proposed modifications of the grille spectrometer are described. This instrument will be part of the atmospheric science research payload flown on the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission planned for late 1990.

  18. Ion mass spectrometer

    NASA Technical Reports Server (NTRS)

    Neugebauer, M. (inventor); Clay, D. R.; Goldstein, B. E.; Goldstein, R.

    1984-01-01

    An ion mass spectrometer is described which detects and indicates the characteristics of ions received over a wide angle, and which indicates the mass to charge ratio, the energy, and the direction of each detected ion. The spectrometer includes a magnetic analyzer having a sector magnet that passes ions received over a wide angle, and an electrostatic analyzer positioned to receive ions passing through the magnetic analyzer. The electrostatic analyzer includes a two dimensional ion sensor at one wall of the analyzer chamber, that senses not only the lengthwise position of the detected ion to indicate its mass to charge ratio, but also detects the ion position along the width of the chamber to indicate the direction in which the ion was traveling.

  19. Imaging Fourier Transform Spectrometer

    SciTech Connect

    Bennett, C.L.; Carter, M.R.; Fields, D.J.; Hernandez, J.

    1993-04-14

    The operating principles of an Imaging Fourier Transform Spectrometer (IFTS) are discussed. The advantages and disadvantages of such instruments with respect to alternative imaging spectrometers are discussed. The primary advantages of the IFTS are the capacity to acquire more than an order of magnitude more spectral channels than alternative systems with more than an order of magnitude greater etendue than for alternative systems. The primary disadvantage of IFTS, or FTS in general, is the sensitivity to temporal fluctuations, either random or periodic. Data from the IRIFTS (ir IFTS) prototype instrument, sensitive in the infrared, are presented having a spectral sensitivity of 0.01 absorbance units, a spectral resolution of 6 cm{sup {minus}1} over the range 0 to 7899 cm{sup {minus}1}, and a spatial resolution of 2.5 mr.

  20. Miniaturized Ion Mobility Spectrometer

    NASA Technical Reports Server (NTRS)

    Kaye, William J. (Inventor); Stimac, Robert M. (Inventor)

    2015-01-01

    By utilizing the combination of a unique electronic ion injection control circuit in conjunction with a particularly designed drift cell construction, the instantly disclosed ion mobility spectrometer achieves increased levels of sensitivity, while achieving significant reductions in size and weight. The instant IMS is of a much simpler and easy to manufacture design, rugged and hermetically sealed, capable of operation at high temperatures to at least 250.degree. C., and is uniquely sensitive, particularly to explosive chemicals.

  1. Rapid scanning mass spectrometer

    SciTech Connect

    Leckey, J.H.; Boeckmann, M.D.

    1996-11-25

    Mass spectrometers and residual gas analyzers (RGA) are used in a variety of applications for analysis of volatile and semi-volatile materials. Analysis is performed by detecting fragments of gas molecules, based on their mass to charge ratio, which are generated in the mass spectrometer. When used as a detector for a gas chromatograph, they function as a means to quantitatively identify isolated volatile species which have been separated from other species via the gas chromatograph. Vacuum Technology, Inc., (VTI) produces a magnetic sector mass spectrometer/RGA which is used in many industrial and laboratory environments. In order to increase the utility of this instrument, it is desirable to increase the mass scanning speed, thereby increasing the number of applications for which it is suited. This project performed the following three upgrades on the computer interface. (1) A new electrometer was designed and built to process the signal from the detector. This new electrometer is more sensitive, over 10 times faster, and over 100 times more stable than the electrometer it will replace. (2) The controller EPROM was reprogrammed with new firmware. This firmware acts as an operating system for the interface and is used to shuttle communications between the PC and the AEROVAC mass spectrometer. (3) The voltage regulator which causes the ion selector voltage to ramp to allow ions of selected mass to be sequentially detected was redesigned and prototyped. The redesigned voltage regulator can be ramped up or down more than 100 times faster than the existing regulator. These changes were incorporated into a prototype unit and preliminary performance testing conducted. Results indicated that scanning speed was significantly increased over the unmodified version.

  2. Energetic ion mass spectrometer

    NASA Technical Reports Server (NTRS)

    Neugebauer, M.; Clay, D. R.; Goldstein, B. E.; Goldstein, R.

    1982-01-01

    A new type of spectrometer for space application has been developed to measure separately mass/charge and the three-dimensional velocity distribution of incident ions. The instrument has relatively high resolution and allows rapid measurement of the four-dimensional set of mass/charge, speed, elevation angle, and azimuth angle. The instrument includes a sector magnet, an electrostatic deflector, microchannel plate detectors with position sensitive readout, and a set of grids with variable applied voltage.

  3. X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2004-01-01

    The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare X R S microcalorimeter spectrometer at the EBIT-I facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolution. The X R S microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high energy resolution by operating at 0.06K and by carefully controlling the heat capacity and thermal conductance. The XRS/EBIT instrument has 32 pixels in a square geometry and achieves an energy resolution of 6 eV at 6 keV, with a bandpass from 0.1 to 12 keV (or more at higher operating temperature). The instrument allows detailed studies of the x-ray line emission of laboratory plasmas. The XRS/EBIT also provides an extensive calibration "library" for the Astro-E2 observatory.

  4. Design and demonstration of phase gratings for 2D single grating interferometer.

    PubMed

    Morimoto, Naoki; Fujino, Sho; Ito, Yasuhiro; Yamazaki, Amane; Sano, Issei; Hosoi, Takuji; Watanabe, Heiji; Shimura, Takayoshi

    2015-11-16

    In this study, we examined five types of phase gratings in a two-dimensional (2D) single grating interferometer with multidot metal targets embedded in a diamond substrate. For a phase grating consisting of two stacked 1D ?/2-phase gratings and a checkerboard ?-phase grating the multidot-pattern self-images with high visibility (40%) were obtained as expected from simulations. In addition to an absorption image, differential phase contrast and dark-field images in both x and y directions were derived from a single image. We also examined face-centered-square multidot metal targets, which doubled the x-ray intensity, and obtained differential phase contrast images in both x and y directions. PMID:26698424

  5. Case study of grate-chain degradation in a Grate-Kiln process

    NASA Astrophysics Data System (ADS)

    Nilsson, Erik A. A.; Pettersson, L.; Antti, M.-L.

    2013-12-01

    Austenitic stainless steels are often used in high temperature applications due to their resistance to corrosion. Grate-Kiln processes that sinter iron ore pellets use grate-chains which are made of austenitic stainless steel to withstand the severe environment. It has been shown, however, that the grate-chain is affected by several degrading mechanisms in the harsh environment of the sintering process. A grate-chain that has been in service for 8 months was investigated in order to find the mechanisms of degradation. Results show that slag products are accumulated on the grate-chain and interact with the steel as hot corrosion. The stainless steel is believed to be sensitized against inter-granular attack by carburization followed by inter-granular attack. The resistance towards degradation seems to decrease with time which is suggested to be caused by depletion of chromium.

  6. Trends and future of fiber Bragg grating sensing technologies: tailored draw tower gratings (DTGs)

    NASA Astrophysics Data System (ADS)

    Lindner, E.; Hartung, A.; Hoh, D.; Chojetzki, C.; Schuster, K.; Bierlich, J.; Rothhardt, M.

    2014-05-01

    Today fiber Bragg gratings are commonly used in sensing technology as well as in telecommunications. Numerous requirements must be satisfied for their application as a sensor such as the number of sensors per system, the measurement resolution and repeatability, the sensor reusability as well as the sensor costs. In addition current challenges need to be met in the near future for sensing fibers to keep and extend their marketability such as the suitability for sterilization, hydrogen darkening or the separation of strain and temperature (or pressure and temperature). In this contribution we will give an outlook about trends and future of the fiber Bragg gratings in sensing technologies. Specifically, we will discuss how the use of draw tower grating technology enables the production of tailored Bragg grating sensing fibers, and we will present a method of separating strain and temperature by the use of a single Bragg grating only, avoiding the need for additional sensors to realize the commonly applied temperature compensation.

  7. Polymer planar Bragg grating for sensing applications

    NASA Astrophysics Data System (ADS)

    Rosenberger, M.; Hartlaub, N.; Koller, G.; Belle, S.; Schmauss, B.; Hellmann, R.

    2013-05-01

    Bragg gratings have become indispensable as optical sensing elements and are already used for a variety of technical applications. Mainly silica fiber Bragg gratings (FBGs) have been extensively studied over the last decades and are nowadays commercially available. Bragg grating sensors consisting of other materials like polymers, however, have only recently come into the focus of fundamental and applied research. Polymers exhibit significantly different properties advantageous for many sensing applications and therefore provide a good alternative to silica based devices. In addition, polymer materials are inexpensive, simple to handle as well as available in various forms like liquid resists or bulk material. Accordingly, polymer integrated optics attract increasing interest and can serve as a substitute for optical fibers. We report on the fabrication of a planar Bragg grating sensor in bulk Polymethylmethacrylate (PMMA). The sensor consists of an optical waveguide and a Bragg grating, both written simultaneously into a PMMA chip by a single writing step, for which a phase mask covered by an amplitude mask is placed on top of the PMMA and exposed to the UV radiation of a KrF excimer laser. Depending on the phase mask period, different Bragg gratings reflecting in the telecommunication wavelength range are fabricated and characterized. Reflection and transmission measurements show a narrow reflection band and a high reflectivity of the polymer planar Bragg grating (PPBG). After connecting to a single mode fiber, the portable PPBG based sensor was evaluated for different measurands like humidity and strain. The sensor performance was compared to already existing sensing systems. Due to the obtained results as well as the rapid and cheap fabrication of the sensor chip, the PPBG qualifies for a low cost sensing element.

  8. Mass spectrometers: instrumentation

    NASA Astrophysics Data System (ADS)

    Cooks, R. G.; Hoke, S. H., II; Morand, K. L.; Lammert, S. A.

    1992-09-01

    Developments in mass spectrometry instrumentation over the past three years are reviewed. The subject is characterized by an enormous diversity of designs, a high degree of competition between different laboratories working with either different or similar techniques and by extremely rapid progress in improving analytical performance. Instruments can be grouped into genealogical charts based on their physical and conceptual interrelationships. This is illustrated using mass analyzers of different types. The time course of development of particular instrumental concepts is illustrated in terms of the s-curves typical of cell growth. Examples are given of instruments which are at the exponential, linear and mature growth stages. The prime examples used are respectively: (i) hybrid instruments designed to study reactive collisions of ions with surfaces: (ii) the Paul ion trap; and (iii) the triple quadrupole mass spectrometer. In the area of ion/surface collisions, reactive collisions such as hydrogen radical abstraction from the surface by the impinging ion are studied. They are shown to depend upon the chemical nature of the surface through the use of experiments which utilize self-assembled monolayers as surfaces. The internal energy deposited during surface-induced dissociation upon collision with different surfaces in a BEEQ instrument is also discussed. Attention is also given to a second area of emerging instrumentation, namely technology which allows mass spectrometers to be used for on-line monitoring of fluid streams. A summary of recent improvements in the performance of the rapidly developing quadrupole ion trap instrument illustrates this stage of instrument development. Improvements in resolution and mass range and their application to the characterization of biomolecules are described. The interaction of theory with experiment is illustrated through the role of simulations of ion motion in the ion trap. It is emphasized that mature instruments play a dominant role in most work using mass spectrometers. This is illustrated with recent results on the chemistry of C+.60 including the formation of covalent adducts with aromatic compounds. Quantitative analysis of methylated nucleosides and structural studies of the anti-cancer drug taxol are also discussed. A compendium of mass spectrometers constructed over the past three years is provided. This includes a variety of hybrid instruments, combinations of sector mass spectrometers with traps, instruments designed to study collision dynamics, and many more.

  9. Discrimination of auditory gratings in birds

    PubMed Central

    Osmanski, Michael S.; Marvit, Peter; Depireux, Didier; Dooling, Robert

    2009-01-01

    Auditory gratings (also called auditory ripples) are a family of complex, broadband sounds with sinusoidally-modulated logarithmic amplitudes and a drifting spectral envelope. These stimuli have been studied both physiologically in mammals and psychophysically in humans. Auditory gratings share spectro-temporal properties with many natural sounds, including species-specific vocalizations and the formant transitions of human speech (Versnel and Shamma, 1998). We successfully trained zebra finches and budgerigars, using operant conditioning methods, to discriminate between flat-spectrum broadband noise and noises with ripple spectra of different densities that moved up or down in frequency at various rates. Results show that discrimination thresholds (minimum modulation depth) increased as a function of increasing grating periodicity and density across all species. Results also show that discrimination in the two species of birds was better at those grating densities and periodicities that are prominent in their species-specific vocalizations. Budgerigars were generally more sensitive than both zebra finches and humans. Both bird species showed greater sensitivity to descending auditory gratings, which mirrors the main direction in their vocalizations. Humans, on the other hand, showed no directional preference even though speech is somewhat downward directional. Overall, our results are suggestive of both common strategies in the processing of complex sounds between birds and mammals and specialized, species–specific variations on that processing in birds. PMID:19427374

  10. Discrimination of auditory gratings in birds.

    PubMed

    Osmanski, Michael S; Marvit, Peter; Depireux, Didier A; Dooling, Robert J

    2009-10-01

    Auditory gratings (also called auditory ripples) are a family of complex, broadband sounds with sinusoidally modulated logarithmic amplitudes and a drifting spectral envelope. These stimuli have been studied both physiologically in mammals and psychophysically in humans. Auditory gratings share spectro-temporal properties with many natural sounds, including species-specific vocalizations and the formant transitions of human speech. We successfully trained zebra finches and budgerigars, using operant conditioning methods, to discriminate between flat-spectrum broadband noise and noises with ripple spectra of different densities that moved up or down in frequency at various rates. Results show that discrimination thresholds (minimum modulation depth) increased as a function of increasing grating periodicity and density across all species. Results also show that discrimination in the two species of birds was better at those grating periodicities and densities that are prominent in their species-specific vocalizations. Budgerigars were generally more sensitive than both zebra finches and humans. Both bird species showed greater sensitivity to descending auditory gratings, which mirrors the main direction in their vocalizations. Humans, on the other hand, showed no directional preference even though speech is somewhat downward directional. Overall, our results are suggestive of both common strategies in the processing of complex sounds between birds and mammals and specialized, species-specific variations on that processing in birds. PMID:19427374

  11. Spectral response characteristics of concave grating demultiplexer

    NASA Astrophysics Data System (ADS)

    Guo, Fuyuan; Wang, Minghua

    2006-09-01

    Based on the characteristic of vector waves which taken part in the multiple beams interference in the focal field of concave grating demultiplexer, the reversibility between emission efficiency and receiving efficiency of the optical waveguides, and the amplitude superposition theorem of multiple beams interference, an original analytic expression of simple spectral response efficiency of concave grating demultiplexer is derived. As the spectral distribution of the actual input optical signal is considered, the Gaussian function spectral distribution for example, the actual responsibility and crosstalk of the concave grating demultiplexer for this input optical signal are introduced. Several analytic expressions offer some useful foundation and novel method for analyzing the responsibility and crosstalk of concave grating demultiplexer. A computing instance of concave grating demultiplexer is given, this instance shows that the actual response efficiency characteristic curve which engaged the Gaussian function spectral distribution of input optical signal is smoother than the simple spectral response efficiency characteristic curve which ignored input optical signal spectral width, the smoothness of actual response efficiency characteristic curve and the actual responsibility are dependent on the spectral half width at one of e square of the maximal intensity of actual input optical signal.

  12. An optical fiber Bragg grating tactile sensor

    NASA Astrophysics Data System (ADS)

    Cowie, Barbara; Allsop, Thomas; Williams, John; Webb, David; Bennion, Ian; Fisher, Matthew

    2007-05-01

    Tactile sensors are needed for many emerging robotic and telepresence applications such as keyhole surgery and robot operation in unstructured environments. We have proposed and demonstrated a tactile sensor consisting of a fibre Bragg grating embedded in a polymer "finger". When the sensor is placed in contact with a surface and translated tangentially across it measurements on the changes in the reflectivity spectrum of the grating provide a measurement of the spatial distribution of forces perpendicular to the surface and thus, through the elasticity of the polymer material, to the surface roughness. Using a sensor fabricated from a Poly Siloxane polymer (Methyl Vinyl Silicone rubber) spherical cap 50 mm in diameter, 6 mm deep with an embedded 10 mm long Bragg grating we have characterised the first and second moment of the grating spectral response when scanned across triangular and semicircular periodic structures both with a modulation depth of 1 mm and a period of 2 mm. The results clearly distinguish the periodicity of the surface structure and the differences between the two different surface profiles. For the triangular structure a central wavelength modulation of 4 pm is observed and includes a fourth harmonic component, the spectral width is modulated by 25 pm. Although crude in comparison to human senses these results clearly shown the potential of such a sensor for tactile imaging and we expect that with further development in optimising both the grating and polymer "finger" properties a much increased sensitivity and spatial resolution is achievable.

  13. Gold coated nano gratings for atom optics

    NASA Astrophysics Data System (ADS)

    Lonij, Vincent; Perreault, John; Kornilov, Oleg; Cronin, Alex

    2007-06-01

    The Van der Waals (VdW) interaction between neutral atoms is important to the dynamics of mechanical systems on nanometer scales. We used diffraction of sodium atoms from nano gratings to measure the Van der Waals potentials for atoms and different surfaces with improved precision. Atoms passing through the grating acquire an additional phase shift due to the attractive potential between the atoms and the grating bars, causing the diffraction pattern to be modified [1]. Previous measurements reported the VdW coefficient for sodium atoms and a silicon-nitride(SiNx) surface [2]. In our experiment we used a SiNx grating coated with a 2 nm layer of gold and we were able to measure a 40% increase in the VdW coefficient due to the gold. We also improved precision by combing results from the sodium diffraction experiment with results from a diffraction experiment with helium atoms on the same gratings. [1] R. E. Grisenti, W. Schollkopf, J. P. Toennies, G. C. Hegerfeldt, and T. Kohler. Phys. Rev. Lett., 83(9):1755, 1999. [2] J. D. Perreault, A. D. Cronin, and T. A. Savas. Phys. Rev. A, 71(5):053612, 2005.

  14. Hyperspectral grating optimization and manufacturing considerations

    NASA Astrophysics Data System (ADS)

    Ziph-Schatzberg, Leah; Swartz, Barry; Warren, Chris; Santman, Jeff; Saleh, Mohammad; Wiggins, Richard; Crifasi, Joe; Comstock, Lovell; Taylor, Kevan

    2015-06-01

    Hyperspectral imaging systems are finding broader applications in both the commercial and aerospace markets. It is becoming clear that to optimize the performance of these systems, their instrument transfer function needs to be tailored for each application. Vis-SWIR systems in the full 400nm to 2500nm waveband present particular design and manufacturing challenges. A single blazed grating is inadequate for a system operating in the full vis-SWIR wavelength range. In addition, optical materials and broad band coatings present a challenge for non-reflective systems. An understanding of the application and wavelengths of interest, combined with a judicious choice of a focal plane array, can then lead to an optimized system for the specific application. The ability to tailor the grating and manufacture a wide variety of grating profiles and substrate shapes becomes a significant performance enabler. This paper will discuss how the use of optical, coating, and grating design/analysis software, combined with grating manufacturing techniques assure meeting high performance requirements for different applications.

  15. Grating tuned unstable resonator laser cavity

    DOEpatents

    Johnson, Larry C.

    1982-01-01

    An unstable resonator to be used in high power, narrow line CO.sub.2 pump lasers comprises an array of four reflectors in a ring configuration wherein spherical and planar wavefronts are separated from each other along separate optical paths and only the planar wavefronts are impinged on a plane grating for line tuning. The reflector array comprises a concave mirror for reflecting incident spherical waves as plane waves along an output axis to form an output beam. A plane grating on the output axis is oriented to reflect a portion of the output beam off axis onto a planar relay mirror spaced apart from the output axis in proximity to the concave mirror. The relay mirror reflects plane waves from the grating to impinge on a convex expanding mirror spaced apart from the output axis in proximity to the grating. The expanding mirror reflects the incident planar waves as spherical waves to illuminate the concave mirror. Tuning is provided by rotating the plane grating about an axis normal to the output axis.

  16. Sampled chirped fiber gratings as distributed pressure sensors

    NASA Astrophysics Data System (ADS)

    Tjin, Swee Chuan; Mohanty, Lipi; Ngo, Nam Quoc

    2004-09-01

    Fiber gratings have been studied for their applications in sensing and communications. Many sensing applications of the uniform fiber Bragg grating, chirped fiber grating and long period grating have been studied, proposed and commercialized. Sampled chirped gratings have been studied for multichannel dispersion compensation in DWDM systems. In this paper, we show that the sampled chirped fiber grating can be used as a distributed pressure sensor. The chirp provides ease of manufacture of many gratings. The sampling results in many small, uniform grating-like structures. This fact can be used to simulate a distributed sensor over the length of the sampled chirped grating. When a surface comes into contact with the sensor, the distribution of the pressure determines the shift in central wavelength of the various sub-gratings. The sub-grating that experiences the maximum pressure will show maximum wavelength shift whereas adjacent sub-gratings will show less shift. This can also give the location of the pressure. The sensor design comprises of a sampled chirped grating embedded in unidirectional fiber-reinforced composite prepreg. The prepreg enhances the mechanical strength and the unidirectional embedding reduces birefringence. The number of layers in the prepreg stack varies the sensitivity. Such distributed pressure sensors can be applied in robotics, ergonomics, and in the biomedical field.

  17. High-resolution imaging spectrometer for recording absolutely calibrated far ultraviolet spectra from laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Brown, Charles M.; Seely, John F.; Feldman, Uri; Holland, Glenn E.; Weaver, James L.; Obenschain, Steven P.; Kjornrattanawanich, Benjawan; Fielding, Drew

    2008-10-01

    An imaging spectrometer was designed and fabricated for recording far ultraviolet spectra from laser-produced plasmas with wavelengths as short as 155 nm. The spectrometer implements a Cassegrain telescope and two gratings in a tandem Wadsworth optical configuration that provides diffraction limited resolution. Spectral images were recorded from plasmas produced by the irradiation of various target materials by intense KrF laser radiation with 248 nm wavelength. Two pairs of high-resolution gratings can be selected for the coverage of two wavebands, one grating pair with 1800 grooves/mm and covering approximately 155-175 nm and another grating pair with 1200 grooves/mm covering 230-260 nm. The latter waveband includes the 248 nm KrF laser wavelength, and the former waveband includes the wavelength of the two-plasmon decay instability at 23 the KrF laser wavelength (165 nm). The detection media consist of a complementary metal oxide semiconductor imager, photostimulable phosphor image plates, and a linear array of 1 mm2 square silicon photodiodes with 0.4 ns rise time. The telescope mirrors, spectrometer gratings, and 1 mm2 photodiode were calibrated using synchrotron radiation, and this enables the measurement of the absolute emission from the laser-produced plasmas with temporal, spatial, and spectral resolutions. The spectrometer is capable of measuring absolute spectral emissions at 165 nm wavelength as small as 510-7 J/nm from a plasma source area of 0.37 mm2 and with 0.4 ns time resolution.

  18. High-resolution imaging spectrometer for recording absolutely calibrated far ultraviolet spectra from laser-produced plasmas

    SciTech Connect

    Brown, Charles M.; Seely, John F.; Feldman, Uri; Holland, Glenn E.; Weaver, James L.; Obenschain, Steven P.; Kjornrattanawanich, Benjawan; Fielding, Drew

    2008-10-15

    An imaging spectrometer was designed and fabricated for recording far ultraviolet spectra from laser-produced plasmas with wavelengths as short as 155 nm. The spectrometer implements a Cassegrain telescope and two gratings in a tandem Wadsworth optical configuration that provides diffraction limited resolution. Spectral images were recorded from plasmas produced by the irradiation of various target materials by intense KrF laser radiation with 248 nm wavelength. Two pairs of high-resolution gratings can be selected for the coverage of two wavebands, one grating pair with 1800 grooves/mm and covering approximately 155-175 nm and another grating pair with 1200 grooves/mm covering 230-260 nm. The latter waveband includes the 248 nm KrF laser wavelength, and the former waveband includes the wavelength of the two-plasmon decay instability at (2/3) the KrF laser wavelength (165 nm). The detection media consist of a complementary metal oxide semiconductor imager, photostimulable phosphor image plates, and a linear array of 1 mm{sup 2} square silicon photodiodes with 0.4 ns rise time. The telescope mirrors, spectrometer gratings, and 1 mm{sup 2} photodiode were calibrated using synchrotron radiation, and this enables the measurement of the absolute emission from the laser-produced plasmas with temporal, spatial, and spectral resolutions. The spectrometer is capable of measuring absolute spectral emissions at 165 nm wavelength as small as 5x10{sup -7} J/nm from a plasma source area of 0.37 mm{sup 2} and with 0.4 ns time resolution.

  19. IR Spectrometer Using 90-Degree Off-Axis Parabolic Mirrors

    SciTech Connect

    Robert M. Malone, Ian J. McKenna

    2008-03-01

    A gated spectrometer has been designed for real-time, pulsed infrared (IR) studies at the National Synchrotron Light Source at the Brookhaven National Laboratory. A pair of 90-degree, off-axis parabolic mirrors are used to relay the light from an entrance slit to an output recording camera. With an initial wavelength range of 1500–4500 nm required, gratings could not be used in the spectrometer because grating orders would overlap. A magnesium oxide prism, placed between these parabolic mirrors, serves as the dispersion element. The spectrometer is doubly telecentric. With proper choice of the air spacing between the prism and the second parabolic mirror, any spectral region of interest within the InSb camera array’s sensitivity region can be recorded. The wavelengths leaving the second parabolic mirror are collimated, thereby relaxing the camera positioning tolerance. To set up the instrument, two different wavelength (visible) lasers are introduced at the entrance slit and made collinear with the optical axis via flip mirrors. After dispersion by the prism, these two laser beams are directed to tick marks located on the outside housing of the gated IR camera. This provides first-order wavelength calibration for the instrument. Light that is reflected off the front prism face is coupled into a high-speed detector to verify steady radiance during the gated spectral imaging. Alignment features include tick marks on the prism and parabolic mirrors. This instrument was designed to complement single-point pyrometry, which provides continuous time histories of a small collection of spots from shock-heated targets.

  20. IR Spectrometer Using 90-degree Off-axis Parabolic Mirrors

    SciTech Connect

    Robert M. Malone, Richard, G. Hacking, Ian J. McKenna, and Daniel H. Dolan

    2008-09-02

    A gated spectrometer has been designed for real-time, pulsed infrared (IR) studies at the National Synchrotron Light ource at the Brookhaven National Laboratory. A pair of 90-degree, off-axis parabolic mirrors are used to relay the light from an entrance slit to an output IR recording camera. With an initial wavelength range of 1500–4500 nm required, gratings could not be used in the spectrometer because grating orders would overlap. A magnesium oxide prism, placed between these parabolic mirrors, serves as the dispersion element. The spectrometer is doubly telecentric. With proper choice of the air spacing between the prism and the second parabolic mirror, any spectral region of interest within the InSb camera array’s sensitivity region can be recorded. The wavelengths leaving the second parabolic mirror are collimated, thereby relaxing the camera positioning tolerance. To set up the instrument, two different wavelength (visible) lasers are introduced at the entrance slit and made collinear with the optical axis via flip mirrors. After dispersion by the prism, these two laser beams are directed to tick marks located on the outside housing of the gated IR camera. This provides first-order wavelength calibration for the instrument. Light that is reflected off the front prism face is coupled into a high-speed detector to verify steady radiance during the gated spectral imaging. Alignment features include tick marks on the prism and parabolic mirrors. This instrument was designed to complement singlepoint pyrometry, which provides continuous time histories of a small collection of spots from shock-heated targets.