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1

Echelle grating multi-order imaging spectrometer utilizing a catadioptric lens  

DOEpatents

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.

Chrisp, Michael P; Bowers, Joel M

2014-05-27

2

Echelle gratings for the near-infrared  

NASA Astrophysics Data System (ADS)

We report on echelle gratings produced by diamond turning with groove spacings coarser than 20 lines per mm. Increasing the groove spacing of an echelle reduces the free spectral range allowing infrared orders to be matched to the detector size. Reflection echelle gratings designed for the near-infrared have potential wide application in both ambient temperature as well as cryogenic astronomical spectrographs. Diamond turned reflection echelle gratings are currently employed in space-based high-resolution spectrographs for 2 - 4 ?m planetary spectroscopy. Using a sample diamond turned grating we investigate the suitability of a 15 line/mm R3 echelle for use in ground-based 1 - 5 ?m spectroscopy. We find this grating suitable for 3 - 5 ?m high signal-to-noise, high-resolution applications. Controlling wavefront errors by an additional factor of two would permit use at high-resolution in the 1.5 - 2.5 ?m region.

Hinkle, Kenneth H.; Joyce, Richard R.; Bach, Bernhard W.; Bach, Erich; Bach, Kirk G.; Beam, Brooke M.; Poczulp, Gary; Smith, Verne V.; Wallace, Lloyd

2012-09-01

3

Astronomical near-infrared echelle gratings  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

4

A Far Infrared Echelle Spectrometer for the Kuiper Airborne Observatory  

NASA Technical Reports Server (NTRS)

A liquid-helium-cooled grating spectrometer (CGS) is being developed as a facility instrument for the Kuiper Airborne Observatory (KAO), primarily to study for infrared lines originating in the interstellar medium. A maximum resolving power of approximately 6000 is achieved by means of a 45 cm long Echelle grating and is optically capable of operating in the spectral range from 25 to 300 microns. An array of detectors is used to simultaneously measure a line and the adjacent continuum from astronomical sources. Currently six detectors allow measurements in the 30 to 120 micron spectral band. The instrument, its operation, and its performance are described.

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

1984-01-01

5

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

6

Coudé echelle spectrometer for the Terskol 2-meter telescope.  

NASA Astrophysics Data System (ADS)

A new echelle spectrometer has been designed for the coudé focus of the 2-meter telescope mounted at the Terskol High-Altitude Station. Three Schmidt cameras used in the spectrometer afford spectral resolutions of 45000, 90000, and 190000 with entrance slit widths of 2? 1?and 0.5? respectively.

Musaev, F. A.; Galazutdinov, G. A.; Sergeev, A. V.; Karpov, N. V.; Pod'Yachev, Yu. V.

7

Diffraction Effects in a Grating Spectrometer  

NASA Technical Reports Server (NTRS)

This paper describes a numerical study of diffraction effects in the AIRES optical system using GLAD by Applied Optics Research. AIRES (or Airborne Infrared Echelle Spectrometer) employs two gratings in series. The small, first-order (i.e., predisperser) grating sorts orders for the large, high-order echelle grating, thus providing moderately high spectral resolution over 3.6 octaves in wavelength. The AIRES' optical design includes three field stops (i.e., a circular aperture and two long, narrow slits) and four pupil stops. A detailed diffraction analysis is required to evaluate critical trade-offs between spectral resolution, optical throughput, detector background, scattered light, and system size and weight. Such an analysis must consider diffraction effects at the pupil stops (edge diffraction), at the field stops (spatial filtering), and at intermediate positions where other optical elements are located. The effects of slit width, slit length, oversizing of the second slit relative to the first, baffling at the Lyot stop and subsequent pupil stops, and the necessity for oversizing other optical elements are presented and discussed. It is found that for narrow slits, the downstream energy distribution is significantly broadened relative to that for large slits, where telescope diffraction dominates, leading to significantly more light loss than anticipated, unless other key optical elements are oversized. The importance of performing a proper diffraction analysis is emphasized and the suitability of GLAD for this task is discussed.

Haas, Michael R.; DeVincenzi, D. (Technical Monitor)

2002-01-01

8

First: Florida Ir Silicon Immersion Grating Spectrometer  

NASA Astrophysics Data System (ADS)

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.

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

2012-01-01

9

Actual blaze angle of the Bausch & Lomb R4 echelle grating  

NASA Technical Reports Server (NTRS)

An innovative procedure is described for measuring blaze angle that is free of systematic effects associated with an alternative approach. The method uses the effect of facet diffraction on the blaze function when an echelle grating is used off-Littrow. The angle measurement in the Littrow condition is wavelength independent and locates the actual direction of the grating facet normal.

Brown, R. A.; Hilliard, R. L.; Phillips, A. L.

1982-01-01

10

AIRES: An Airborne Infra-Red Echelle Spectrometer for SOFIA  

NASA Technical Reports Server (NTRS)

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.

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

11

Exploiting a Transmission Grating Spectrometer  

SciTech Connect

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.

Ronald E. Bell

2004-12-08

12

Convex Diffraction Grating Imaging Spectrometer  

NASA Technical Reports Server (NTRS)

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.

Chrisp, Michael P. (Inventor)

1999-01-01

13

Micro IR Spectrometer Based on Blaze Grating  

Microsoft Academic Search

An infrared spectrometer which employs a blaze grating as well as an 8-element thermopile array is designed, fabricated and tested in this paper. The grating which has 80 grooves of 19.2deg blazing angle and 5 mum grating constant is precisely defined by an anisotropic etching in KOH solution from a carefully cut silicon wafer. After bonded to wafers consisting of

Hong Zhou; Tie Li; Yi Wang; Xinxin Li; Yuelin Wang

2007-01-01

14

Compact Imaging Spectrometer Utilizing Immersed Gratings  

DOEpatents

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.

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

2006-03-21

15

Using a retro-reflecting echelle grating to improve WDM demux efficiency  

Microsoft Academic Search

The use of uncoated facets on the echelle grating in a monolithic InP WDM demux leads to a reflection loss of 5.65 dB for an index of refraction of approximately 3.18. This loss can be largely eliminated by coating the out of plane facet with gold, but it involves another processing step. An alternative is to use total internal reflecting

L. Erickson; B. Lamontagne; J. J. He; A. Delage; M. Davies; E. Koteles

1997-01-01

16

Design of a mid-IR immersion echelle grating spectrograph for remote sensing  

SciTech Connect

We describe the design of a silicon immersion grating spectrograph for the remote detection of chemicals in the atmosphere. The instrument is designed to operate in the two atmospheric windows from 2.3 to 2.5 and 2.8 and 4.2 microns at a resolution of 0.1 cm{sup {minus}1}. This is achieved by cross dispersing a high order silicon immersion echelle (13.5 grooves/mm) and a first order concave grating operating in a reflective configuration to generate a two-dimensional spectrum in the image plane with diffraction limited performance.

Thomas, N.L.; Lewis, I.T.; Stevens, C.G.

1995-05-09

17

An FIR cooled grating spectrometer for the Kuiper Airborne Observatory  

NASA Technical Reports Server (NTRS)

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.

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

18

Compact imaging spectrometer utilizing immersed gratings  

DOEpatents

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.

Lerner, Scott A.

2005-12-20

19

Compact imaging spectrometer utilizing immersed gratings  

DOEpatents

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.

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

2007-07-03

20

Compact reflective imaging spectrometer utilizing immersed gratings  

DOEpatents

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.

Chrisp, Michael P. (Danville, CA)

2006-05-09

21

Micro Ring Grating Spectrometer with Adjustable Aperture  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

22

New Convex Grating Types for Concentric Imaging Spectrometers  

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

23

Electro-optic Phase Grating Streak Spectrometer  

SciTech Connect

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.

Goldin, F. J.

2012-08-02

24

The Constellation-X reflection grating spectrometer Jean Cottama  

E-print Network

The Constellation-X reflection grating spectrometer Jean Cottama , Webster Cashb , Kathryn A University, SLAC, Menlo Park, CA USA 94025 ABSTRACT The Constellation-X Reflection Grating Spectrometer (RGS. Keywords: X-ray, spectrometer, grating, CCD, Constellation-X 1. INTRODUCTION Constellation-X1 is one

25

Imaging Spectrometers Using Concave Holographic Gratings  

NASA Technical Reports Server (NTRS)

Imaging spectroscopy combines the spatial attributes of imaging with the compositionally diagnostic attributes of spectroscopy. For spacebased remote sensing applications, mass, size, power, data rate, and application constrain the scanning approach. For the first three approaches, substantial savings in mass and size of the spectrometer can be achieved in some cases with a concave holographic grating and careful placement of an order-sorting filter. A hologram etched on the single concave surface contains the equivalent of the collimating, dispersing, and camera optics of a conventional grating spectrometer and provides substantial wavelength dependent corrections for spherical aberrations and a flat focal field. These gratings can be blazed to improve efficiency when used over a small wavelength range or left unblazed for broadband uniform efficiency when used over a wavelength range of up to 2 orders. More than 1 order can be imaged along the dispersion axis by placing an appropriately designed step order-sorting filter in front of the one- or two-dimensional detector. This filter can be shaped for additional aberration corrections. The VIRIS imaging spectrometer based on the broadband design provides simultaneous imaging of the entrance slit from lambda = 0.9 to 2.6 microns (1.5 orders) onto a 128 x 128 HgCdTe detector (at 77 K). The VIRIS spectrometer was used for lunar mapping with the UH 24.in telescope at Mauna Kea Observatory. The design is adaptable for small, low mass, space based imaging spectrometers.

Gradie, J.; Wang, S.

1993-01-01

26

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)

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.

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

2014-08-01

27

Single-detector micro-electro-mechanical scanning grating spectrometer  

Microsoft Academic Search

A compact, robust grating spectrometer based on an optimised micro-electro-mechanical grating mirror component has been developed,\\u000a built, and characterised. The application of an oscillating reflection grating micro-mirror component as scanning dispersive\\u000a element in a modified Czerny–Turner monochromator layout enables the design of compact grating spectrometers capable of acquiring\\u000a full spectra using a single detector element. Designed for a wavelength range

M. Kraft; A. Kenda; A. Frank; W. Scherf; A. Heberer; T. Sandner; H. Schenk; F. Zimmer

2006-01-01

28

Cooled grating infrared spectrometer for astronomical observations  

NASA Technical Reports Server (NTRS)

A liquid helium-cooled infrared spectrometer for the 16 to 50 micron range is described. The instrument has six detectors, three each of Si:Sb and Ge:Ga and two diffraction gratings mounted back-to-back. Cold preoptics are used to match the spectrometer to the telescope. In its nominal configuration the system resolution is 0.03 micron from 16 to 30 microns and 0.07 micron from 28 to 50 microns. A cooled filter wheel is used to change order sorting filters. The gratings are driven by a steel band and gear train operating at 4 K. The detector outputs are amplified by a TIA, employing a matched pair of JFETs operating at 70 K inside the dewar. The external warm electronics include a gain stage for the TIA and dc-coupled gating circuit to remove charged-particle (cosmic-ray secondary)-induced noise spikes. The gating circuit reduces the overall system noise by a factor of two when the spectrometer is used on NASA's Kuiper Airborne Observatory. Sample spectra are presented and the deglitcher performance is illustrated.

Houck, J. R.; Gull, G. E.

1983-01-01

29

Compact catadioptric imaging spectrometer utilizing reflective grating  

DOEpatents

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.

Lerner, Scott A.

2005-12-27

30

A transmission grating spectrometer for plasma diagnostics  

SciTech Connect

Radiation temperature is an important parameter in characterizing the properties of hot plasmas. In most cases this temperature is time varying caused by the short lived and/or time dependent nature of the plasma. Thus, a measurement of the radiation flux as a function of time is quite valuable. To this end the authors have developed a spectrometer that can acquire spectra with a time resolution of less than 1 ns and covers the spectral energy range from {approximately} 60 to 1,000 eV. The spectrometer consists of an entrance slit placed relatively near the plasma, a thin gold film transmission grating with aperture, a micro channel plate (MCP) detector with a gold cathode placed at the dispersion plane and an electron lens to focus the electrons from the MCP onto a phosphor coated fiber optic plug. The phosphor (In:CdS) has a response time of {approximately} 500 ps. This detector system, including the fast phosphor is similar to one that has been previously described. The spectrometer is in a vacuum chamber that is turbo pumped to a base pressure of {approximately} 5 x 10{sup 7} torr. The light from the phosphor is coupled to two streak cameras through 100 m long fiber optic cables. The streak cameras with their CCD readouts provide the time resolution of the spectrum. The spectrometer has a built in alignment system that uses an alignment telescope and retractable prism.

Bartlett, R.J.; Hockaday, R.G. [Los Alamos National Lab., NM (United States); Gallegos, C.H.; Gonzales, J.M.; Mitton, V. [EG and G Energy Measurements, Los Alamos, NM (United States)

1995-09-01

31

Angle Transmission Grating Spectrometer for the International X Spectrometer for the International X- Ray Observatory  

Microsoft Academic Search

We have developed a new type of soft x-ray diffraction grating. This critical-angle transmission (CAT) grating (1-4) combines the advantages of traditional transmission gratings (very low mass, extremely relaxed alignment and flatness tolerances) with those of x-ray reflection gratings (high efficiency due to blazing in the direction of grazing-incidence reflection). In addition, grating spectrometers based on CAT gratings are well-suited

Ralf K. Heilmann; Minseung Ahn; Kathryn A. Flanagan; David P. Huenemoerder; M. L. Schattenburg

32

Faceted grating prism for a computed tomographic imaging spectrometer  

E-print Network

Faceted grating prism for a computed tomographic imaging spectrometer Michael W. Kudenov Julia://opticalengineering.spiedigitallibrary.org/ on 02/04/2013 Terms of Use: http://spiedl.org/terms #12;Faceted grating prism for a computed tomographic disperser based on a 2-D grating prism and a division of aperture approach. Included is an optical design

Dereniak, Eustace L.

33

Quantitative analysis of mercury in silver dental amalgam alloy using laser induced breakdown spectroscopy with a portable Echelle spectrometer  

Microsoft Academic Search

Nowadays it is commonly ascertained that, Laser- induced breakdown spectroscopy (LIBS) was investigated to evaluate the feasibility as a fast, accurate, non contact and simple technique used in both qualitative and quantitative elemental analysis of metals in various environments. The used portable Echelle spectrometer (Mechelle 7500 - Multichannel Instruments, Stockholm, Sweden) permit real simultaneous multi-elemental analysis in rang of 200-900

Walid Tawfik; Ali Saafan

34

Immersion echelle spectrograph  

DOEpatents

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.

Stevens, Charles G. (Danville, CA); Thomas, Norman L. (Livermore, CA)

2000-01-01

35

Spectral calibration for convex grating imaging spectrometer  

NASA Astrophysics Data System (ADS)

Spectral calibration of imaging spectrometer plays an important role for acquiring target accurate spectrum. There are two spectral calibration types in essence, the wavelength scanning and characteristic line sampling. Only the calibrated pixel is used for the wavelength scanning methods and he spectral response function (SRF) is constructed by the calibrated pixel itself. The different wavelength can be generated by the monochromator. The SRF is constructed by adjacent pixels of the calibrated one for the characteristic line sampling methods. And the pixels are illuminated by the narrow spectrum line and the center wavelength of the spectral line is exactly known. The calibration result comes from scanning method is precise, but it takes much time and data to deal with. The wavelength scanning method cannot be used in field or space environment. The characteristic line sampling method is simple, but the calibration precision is not easy to confirm. The standard spectroscopic lamp is used to calibrate our manufactured convex grating imaging spectrometer which has Offner concentric structure and can supply high resolution and uniform spectral signal. Gaussian fitting algorithm is used to determine the center position and the Full-Width-Half-Maximum?FWHM?of the characteristic spectrum line. The central wavelengths and FWHMs of spectral pixels are calibrated by cubic polynomial fitting. By setting a fitting error thresh hold and abandoning the maximum deviation point, an optimization calculation is achieved. The integrated calibration experiment equipment for spectral calibration is developed to enhance calibration efficiency. The spectral calibration result comes from spectral lamp method are verified by monochromator wavelength scanning calibration technique. The result shows that spectral calibration uncertainty of FWHM and center wavelength are both less than 0.08nm, or 5.2% of spectral FWHM.

Zhou, Jiankang; Chen, Xinhua; Ji, Yiqun; Chen, Yuheng; Shen, Weimin

2013-12-01

36

Accurate wavelength calibration method using system parameters for grating spectrometers  

NASA Astrophysics Data System (ADS)

In this paper, an accurate method is proposed for wavelength calibration in grating spectrometers. The analytical calibration model of the Czerny-Turner optical system, which describes the relationship between the wavelengths and the pixel numbers with function of the system parameters, is established on the basis of the grating equation and geometric optics. An optimization fitting algorithm is introduced to calculate the practical system parameter values in this model. Experimental tests are conducted in our manufactured spectrometer. The results show that this method has higher calibration accuracy in a broadband spectrometer system and less dependence on the spectral lines chosen compared to the traditional polynomial method. This novel wavelength calibration method also can be applied to other plane-grating or concave-grating spectrometers.

Liu, Kang; Yu, Feihong

2013-01-01

37

Imaging Spectrometer Designs Utilizing Immersed Gratings With Accessible Entrance Slit  

DOEpatents

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.

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

2006-03-21

38

Infrared micro-spectrometer based on a diffraction grating  

Microsoft Academic Search

The optical properties of crystalline silicon in the IR spectral range have been used for the realisation of a grating type micro-spectrometer. An aluminium metallisation on a double side polished silicon wafer is used for fabrication of the multi-slit gratings. The dispersed spectrum propagates through this silicon wafer and is projected on an array of polysilicon thermopiles, integrated in a

S. H. Kong; D. D. L. Wijngaards; R. F. Wolffenbuttel

2001-01-01

39

Compact Catadioptric Imaging Spectrometer Designs Utilizing Immersed Gratings  

DOEpatents

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.

Lerner, Scott A. (Livermore, CA)

2006-02-28

40

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

NASA Astrophysics Data System (ADS)

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.

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

41

Micro-sized spectrometer based on a lamellar grating interferometer  

Microsoft Academic Search

A lamellar grating interferometer (LGI) realized by silicon micro-machining is presented. The LGI is a binary grating with a variable depth. The motion is carried out by an electrostatic comb drive actuator fabricated by silicon-on-insulator (SOI) technology. It is used as Fourier transform spectrometer (FTS). We have measured an optical path difference maximum of 82 ?m. The measured resolution of

O. Manzardo; R. Michaely; F. Schadelin; H. P. Herzig

2003-01-01

42

Compact Refractive Imaging Spectrometer Designs Utilizing Immersed Gratings  

DOEpatents

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

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

43

The polarisation correction for space-borne grating spectrometers  

NASA Astrophysics Data System (ADS)

Satellite measurements of backscattered sunlight contain essential information about the global distribution of atmospheric constituents. Light reflected from the Earth's atmosphere is linearly or partially linearly polarized because of scattering of unpolarized sunlight by air molecules and aerosols. In the ultraviolet and visible part of the spectrum, measurements of space-borne grating spectrometers are in general sensitive to the state of polarization of the observed light. The interaction of polarized light with polarization-sensitive optical devices yields a different radiance that is measured by the detectors than the radiance that enters the instrument. In the OMI and the SBUV/2 instruments the problem of instrument polarization sensitivity is avoided because the polarized backscattered sunlight is depolarized before it interacts with the polarization-sensitive optical components. For GOME, SCIAMACHY, and GOME-2 it is intended to eliminate the polarization response of the instrument from the polarization-sensitive measurement. This paper discusses the basic concept of the polarisation correction of the space-borne grating spectrometers by using Mueller matrix calculus. A model was developed using the Mueller Matrices formulation to evaluate the polarization sensitivity of the space-borne grating spectrometers. The optical components are treated as general diattenuators with phase retardance. The correction for this polarization sensitivity is based on broadband polarization measurements. Accurate preflight polarisation calibration of space-borne grating spectrometers is essential for the observational objectives of the instrument, and a special facility has been developed in order to allow the instrument to be calibrated.

Zhao, Fa-cai; Sun, Quan-she; Chen, Kun-feng; Zhu, Xing-bang; Wang, Shao-shui; Wang, Guo-quan; Zheng, Xiang-liang; Han, Zhong

2014-02-01

44

A transmission grating spectrometer for plasma diagnostics  

Microsoft Academic Search

Radiation temperature is an important parameter in characterizing the properties of hot plasmas. In most cases this temperature is time varying caused by the short lived and\\/or time dependent nature of the plasma. Thus, a measurement of the radiation flux as a function of time is quite valuable. To this end we have developed a spectrometer that can acquire spectra

R. J. Bartlett; R. G. Hockaday; C. H. Gallegos; J. M. Gonzales; V. Mitton

1995-01-01

45

A transmission grating spectrometer for plasma diagnostics  

Microsoft Academic Search

Radiation temperature is an important parameter in characterizing the properties of hot plasmas. In most cases this temperature is time varying caused by the short lived and\\/or time dependent nature of the plasma. Thus, a measurement of the radiation flux as a function of time is quite valuable. To this end the authors have developed a spectrometer that can acquire

Roger J. Bartlett; Robert G. Hockaday; Cenobio H. Gallegos; Joseph M. Gonzales; Vance Mitton

1995-01-01

46

The Reflection Grating Spectrometer on board XMM-Newton  

Microsoft Academic Search

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 Å, or 2.1 to 0.3 keV) with a maximum effective area of about 140 cm2

J. W. den Herder; A. C. Brinkman; S. M. Kahn; G. Branduardi-Raymont; K. Thomsen; H. Aarts; M. Audard; J. V. Bixler; A. J. den Boggende; J. Cottam; T. Decker; L. Dubbeldam; C. Erd; H. Goulooze; M. Güdel; P. Guttridge; C. J. Hailey; K. Al Janabi; J. S. Kaastra; P. A. J. de Korte; B. J. van Leeuwen; C. Mauche; A. J. McCalden; R. Mewe; A. Naber; F. B. Paerels; J. R. Peterson; A. P. Rasmussen; K. Rees; I. Sakelliou; M. Sako; J. Spodek; M. Stern; T. Tamura; J. Tandy; C. P. de Vries; S. Welch; A. Zehnder

2001-01-01

47

Solar Imaging UV/EUV Spectrometers Using TVLS Gratings  

NASA Technical Reports Server (NTRS)

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.

Thomas, Roger J.

2003-01-01

48

System design of multi-function grating spectrometer  

NASA Astrophysics Data System (ADS)

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.

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

2010-10-01

49

Development of a Submillimeter-Wavelength Immersion Grating Spectrometer  

NASA Technical Reports Server (NTRS)

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.

Phillips, T. G.

2001-01-01

50

Laboratory radiometric calibration for the convex grating imaging spectrometer  

NASA Astrophysics Data System (ADS)

The radiometric calibration of imaging spectrometer plays an import role for scientific application of spectral data. The radiometric calibration accuracy is influenced by many factors, such as the stability and uniformity of light source, the transfer precision of radiation standard and so on. But the deviation from the linear response mode and the polarization effect of the imaging spectrometer are always neglected. In this paper, the linear radiometric calibration model is constructed and the radiometric linear response capacity is test by adjusting electric gain, exposure time and radiance level. The linear polarizer and the sine function fitting algorithm are utilized to measure polarization effect. The integrating sphere calibration system is constructed in our Lab and its spectral radiance is calibrated by a well-characterized and extremely stable NIST traceable transfer spectroradiometer. Our manufactured convex grating imaging spectrometer is relative and absolute calibrated based on the integrating sphere calibration system. The relative radiometric calibration data is used to remove or reduce the radiometric response non-uniformity every pixel of imaging spectrometer while the absolute radiometric calibration is used to construct the relationship between the physical radiant of the scene and the digital number of the image. The calibration coefficients are acquired at ten radiance levels. The diffraction noise in the images can be corrected by the calibration coefficients and the uniform radiance image can be got. The calibration result shows that our manufactured imaging spectrometer with convex grating has 3.0% degree of polarization and the uncertainties of the relative and absolute radiometric calibrations are 2.4% and 5.6% respectively.

Zhou, Jiankang; Chen, Xinhua; Chen, Yuheng; Ji, Yiqun; Shen, Weimin

2014-09-01

51

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

NASA Astrophysics Data System (ADS)

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 2.45?m 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 1? x 15? and the plate scale is 0.27? 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.

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

52

All-aluminum optical system for a large cryogenically cooled far infrared echelle spectrometer  

NASA Technical Reports Server (NTRS)

In the past few years, NASA's Kuiper Airborne Observatory (KAO) has made it possible to conduct pioneering observations of far infrared lines from astronomical sources. Such observations, in the case of wavelengths in the approximate range from 20 to 350 microns, cannot be performed from ground-based sites, because of telluric water absorption effects. Lines in the considered range provide information about the interstellar gas in molecular, neutral atomic, and ionized form of occurrence. The present paper provides a description of the development of the cryogenic optical system of a spectrometer designed to exploit the potential of the KAO for observing the far infrared lines. Attention is given to design goals and considerations, details of optical design, the fabrication of the optical system, the cryostat, and performance.

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

1985-01-01

53

Design and fabrication of a Fourier transform spectrometer by means of thermally actuated tunable grating  

Microsoft Academic Search

In this article, the design and fabrication of a Fourier transform spectrometer, based on a thermally actuated tunable grating, are presented. Grooves of a binary grating are filled with nitrobenzene, the refractive index of which highly depends on temperature. Through the application of heat, the temperature of the nitrobenzene is changed, which in turn changes the efficiency of the grating.

Mohammadreza Riahi

54

Next Generation Grating Spectrometer Sounders for LEO and GEO  

NASA Technical Reports Server (NTRS)

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

Pagano, Thomas S.

2011-01-01

55

The Reflection Grating Spectrometer on Board XMM-Newton  

NASA Technical Reports Server (NTRS)

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.

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

56

A simple scanning spectrometer based on a stretchable elastomeric reflective grating  

SciTech Connect

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.

Ghisleri, C.; Milani, P., E-mail: paolo.milani@mi.infn.it [CIMAINA and Dipartimento di Fisica, Università di Milano, via Celoria 16, 20133 Milano (Italy); WISE srl, Piazza Duse 2, 20122 Milano (Italy); Potenza, M. A. C.; Bellacicca, A. [CIMAINA and Dipartimento di Fisica, Università di Milano, via Celoria 16, 20133 Milano (Italy); Ravagnan, L. [WISE srl, Piazza Duse 2, 20122 Milano (Italy)

2014-02-10

57

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)

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.

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

2014-02-01

58

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

SciTech Connect

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.

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

2010-01-31

59

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

NASA Technical Reports Server (NTRS)

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.

Schattenburg, Mark L.

2003-01-01

60

Analysis of a Hadamard transform near-infrared spectrometer based on grating light modulator  

Microsoft Academic Search

This paper proposes a novel Hadamard Transform near-infrared spectrometer based on MOEMS(Optical micro-electro-mechanical system ) grating light modulator. A new method that grating light modulator combined with a single near -infrared detector to detect spectrum is applied. The programmability of the grating light modulator linear array is used to implement a Hadamard Transform encoding masks. Firstly, optics theory has been

Wei Wei; Shanglian Huang; Yong Zhu; Ning Wang; Jie Zhang; Zhu Jin

2008-01-01

61

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

DOEpatents

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.

Lerner, Scott A. (Corvalis, OR)

2006-01-10

62

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

NASA Astrophysics Data System (ADS)

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.

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

2012-09-01

63

X-ray and extended UV spectrometer designs based on off-plane grating mountings  

Microsoft Academic Search

In this contribution a spectrometer design is presented with which it is possible to cover the entire wavelength range of GRIST by one focal plane instrument. This design is based on an off-plane grating mounting, by some other authors indicated with conical diffraction. In contrast with classical grating mountings object and spectral images are located out of the plane perpendicular

W. Werner

1981-01-01

64

Spectrometer concept and design for X-ray astronomy using a blazed transmission grating  

E-print Network

-8084 Optics for EUV, X-Ray, and Gamma-Ray Astronomy III, edited by Stephen L. O'Dell, Giovanni Pareschi ProcSpectrometer concept and design for X-ray astronomy using a blazed transmission grating Kathryn nanofabricated blazed X-ray transmission grating which is modeled to have superior efficiency. Here we outline

65

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

NASA Astrophysics Data System (ADS)

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.

Biao, Luo; Wen, Zhi-yu

2014-01-01

66

Soft X-Ray Critical-Angle Transmission Grating Spectrometer for the International X-Ray Observatory  

Microsoft Academic Search

We have developed a new type of soft x-ray diffraction grating. This critical-angle transmission (CAT) grating [1-4] combines the advantages of traditional transmission gratings (very low mass, extremely relaxed alignment and flatness tolerances) with those of x-ray reflection gratings (high efficiency due to blazing in the direction of grazing-incidence reflection). In addition, grating spectrometers based on CAT gratings are well-suited

Ralf K. Heilmann; M. Ahn; K. A. Flanagan; D. P. Huenemoerder; M. L. Schattenburg

2009-01-01

67

Development of a critical-angle transmission grating spectrometer for the International X-Ray Observatory  

NASA Astrophysics Data System (ADS)

We present a high-resolution soft x-ray grating spectrometer concept for the International X-Ray Observatory (IXO) that meets or exceeds the minimum requirements for effective area (> 1, 000 cm2 for E < 1 keV) and spectral resolution (E/?E > 3, 000). At the heart of the spectrometer is an array of recently developed highefficiency blazed transmission gratings, the so-called critical-angle transmission (CAT) gratings. They combine the advantages of traditional transmission gratings (very low mass, extremely relaxed alignment and flatness tolerances) with those of x-ray reflection gratings (high efficiency due to blazing in the direction of grazing-incidence reflection). In addition, a CAT grating spectrometer is well-suited for co-existence with energy-dispersive highenergy focal plane detectors, since most high-energy x rays are neither absorbed, nor diffracted, and contribute to the effective area at the telescope focus. Since our initial successful x-ray demonstrations of the CAT grating concept with large-period and lower aspect-ratio prototypes, we have now microfabricated 200 nm-period silicon CAT gratings comprised of grating bars with the required dimensions (6 micron tall, 40 nm wide, aspect ratio 150), optimized for the 0.3 to 1.0 keV energy band. Preliminary analysis of recent x-ray tests show blazing behavior up to 1.28 keV in accordance with predictions.

Heilmann, Ralf K.; Ahn, Minseung; Bautz, Marshall W.; Foster, Richard; Huenemoerder, David P.; Marshall, Herman L.; Mukherjee, Pran; Schattenburg, Mark L.; Schulz, Norbert S.; Smith, Matthew

2009-08-01

68

Passive Spectroscopy Bolometers, Grating- And X-ray Imaging Crystal Spectrometers  

SciTech Connect

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 also of particular interest for profile measurements of the ion temperature and plasma rotation velocity on ITER and future burning plasma experiments.

Bitter, M.; Hill, K. W.; Scott, S.; Paul, S. [Princeton Plasma Physics Laboratory, Princeton, NJ, 08543 (United States); Ince-Cushman, A.; Reinke, M.; Rice, J. E. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Beiersdorfer, P.; Gu, M. F. [Lawrence Livermore national Laboratory, Livermore, CA 94550-9234 (United States); Lee, S. G. [Korea Basic Science Institute, Taejeon 305-333 (Korea, Republic of); Broennimann, Ch.; Eikenberry, E. F. [Paul Scherrer Institut, CH5232 Villigen-PSI (Switzerland)

2008-03-12

69

Portable NIR\\/MIR Fouriertransform spectrometer based on a common path lamellar grating interferometer  

Microsoft Academic Search

We present a recently developed miniature scanning Fourier-Transform spectrometer (ARCspectro ANIR), which is based on a lamellar grating interferometer and uses a micro-mechanical actuator. The small dimensions of the interferometer (35 mm x 35 mm x 65 mm) and its low weight makes this device a truly portable Fourier-Transform spectrometer. Two different versions of this new spectrometer are presented: one

F. Merenda; S. Bühler; H. Farah; G. Boer; T. Scharf

2010-01-01

70

Development of two-grating spectrometer for the charge exchange spectroscopy system on KSTAR  

SciTech Connect

The charge exchange spectroscopy (CES) system on Korea Superconducting Tokamak Advanced Research (KSTAR) was installed last year and had been applied to measure the C VI ion temperature and rotation velocity profiles. The ion temperature and rotation velocity profiles had been estimated from the C VI 5290.5 A (n = 8-7) charge-exchange spectrum signal measured by a Czerny-Turner type spectrometer and a thinned back-illuminated charge coupled device (CCD) camera. However, the Czerny-Turner type spectrometer used for the KSTAR CES system showed so low signal to noise ratio for KSTAR plasmas in the 2010 experimental campaign that the time resolution of the CES system had been limited to 100 ms due to the increased exposure time of the attached CCD camera. Then, new two-grating spectrometer had been developed in order to improve the time resolution of the CES system. The spectrometer consists of two gratings (1200 g/mm and 1800 g/mm each) with additive configuration, concave mirrors (f = 50 cm), and a cylindrical lens (f = 50 cm). The time resolution of the CES system increases by a factor of 2-4 with the two-grating spectrometer. The C VI ion temperature and rotation velocity profiles obtained by the two-grating spectrometer are compared to those by Czerny-Turner type spectrometer in this paper.

Lee, Hyungho [Department of Nuclear Fusion and Plasma Science, University of Science and Technology (UST), Gajungro 217, Daejeon 305-350 (Korea, Republic of); National Fusion Research Institute (NFRI), Gwahangno113, Daejeon 305-333 (Korea, Republic of); Song, Eun-ji; Oh, Soo-ghee [Division of Energy Systems Research, Ajou University, Suwon 443-749 (Korea, Republic of); Park, Young-dong [Department of Chemistry, Ajou University, Suwon 443-749 (Korea, Republic of); Ko, Won-Ha [National Fusion Research Institute (NFRI), Gwahangno113, Daejeon 305-333 (Korea, Republic of)

2011-06-15

71

Design and optimization of optical system for a spectrometer based on VPHT grating  

NASA Astrophysics Data System (ADS)

To overcome some drawbacks of optical system for plane and concave grating typed spectrometer, including serious aberration, worse spectral fatness and low diffraction efficiency etc, a novel optical system based on volume phase holographic transmission (VPHT) grating was designed in this paper. For this grating, its manufacture and theories were investigated, and its diffraction efficiency was numerically simulated. In order to validate this designed optical system, the spectral scaling experiment was performed and the spectral resolution reached 2nm, the calibration equation between the scaling wavelength and corresponding pixels was gotten via linear least square fitting algorithm. It was proved that the wavelength absolute value reach 1.7nm on the wavelength of 635nm, the root-mean-square error (RMSE) of full scaling wavelengths was 0.3nm. These experimental results illustrated that the design of the optical system for spectrometer based on VPHT grating is good.

Ren, Zhong; Liu, Guodong; Huang, Zhen; Xiong, Zhihua

2014-11-01

72

Development of a novel spectrometer for tongue coating analyzer based on volume holography transmissive grating  

NASA Astrophysics Data System (ADS)

Tongue diagnosis (TD) is an important diagnostic methods in the traditional Chinese medicine (TCM). According to the viewpoint of TCM, the changes of the tongue coating (TC) can reflect the pathological state of the patient. And the nature or severity of diseasec can be determined by observing the TC. Over the years, TD is mostly depended on the subjective experience of the Chinese physician. And the diagnostic results will be impacted by.some factors, e.g. the different light sources or environmental brightness. Recently years, the method of digital image processing has been used into the TD. But its application is limited by the complicated algorithm, time-consuming and big error, etc. Therefore, a novel tongue coating analyzer(TCA) is designed in this paper. Meanwhile, a novel spectrometer for TCA based on the volume holography transmissive (VHT) grating is developed. In this spectrometer, since the VHT grating doesn't produce the stray-light due to the absence of the grooves of classical surface-embossed gratings, the VHT grating is used as the diffraction grating instead of the classical plane or concave grating. Experimental results show that the performances of the spectrometer for TCA have been improved by using the VHT grating, optimizing the light-path structure and software algorithm, etc. Compared with the others, this spectrometer for TCA has many advantages, such as, less diffraction, wider spectrum range, higher efficiency and resolution, etc. The spectrum range of the spectrometer for TCA can reach 300-1000nm, its resolution can reach 1nm and the optical density is larger than 3.

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

2010-11-01

73

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

PubMed

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

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

1988-08-15

74

Transmission Grating Spectrometer for Constellation-X White paper response to NASA solicitation 210S-GBG-06-001  

E-print Network

1 Transmission Grating Spectrometer for Constellation-X White paper response to NASA solicitation several advantages over reflection grating spectrometers considered for Constellation-X: lower mass The TGS will recover critical science areas for Constellation-X that cannot be achieved with the basic

Heilmann, Ralf

75

Z-Spec: a broadband millimeter-wave grating spectrometer: design, construction, and first cryogenic measurements  

Microsoft Academic Search

We present the design, integration, and first ryogenic testing of our new broad-band millimeter-wave spectrometer, Z-Spec. Z-Spec uses a novel architecture called WaFIRS (Waveguide Far-IR Spectrometer), which employs a curved diffraction grating in a parallel-plate waveguide propagation medium. The instrument will provide a resolving power betwee 200 and 350 across an instantaneous bandwidth of 190-310 GHz, all packaged within a

C. Matt Bradford; Peter A. R. Ade; James E. Aguirre; James J. Bock; Mark Dragovan; Lionel Duband; Lieko Earle; Jason Glenn; Hideo Matsuhara; Bret J. Naylor; Hien T. Nguyen; Minhee Yun; Jonas Zmuidzinas

2004-01-01

76

Micro-Electro-Mechanical-Systems-Based Infrared Spectrometer Composed of Multi-Slit Grating and Bolometer Array  

Microsoft Academic Search

A micro-electro-mechanical-systems (MEMS)-based IR spectrometer has been designed and fabricated. The proposed micro-spectrometer consists of multi-slit grating and bolometric IR detector array. The grating is used for dispersion of an incident optical radiation into different wavelength components. The grating structure is patterned by reactive ion etching (RIE) of aluminum deposited on dielectric membrane, which is fabricated over silicon wafer. The

Jae Chang Yang; Ho Jung; Gwang Jun Lee; Jin-Yeong Kang; Jin-Gun Koo; Jong-Moon Park; Kun-Sik Park; Seong Ho Kong

2008-01-01

77

Design of a hybrid-integrated MEMS scanning grating spectrometer  

Microsoft Academic Search

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

Tino Pügner; Jens Knobbe; Heinrich Grüger; Harald Schenk

2011-01-01

78

Design of highly reflective subwavelength diffraction gratings for use in a tunable spectrometer  

Microsoft Academic Search

The design of highly reflective subwavelength gratings (SWGs) for use in a micro-electromechanical system (MEMS) tunable spectrometer is presented. The SWGs are designed to be polarization independent at an incident wavelength of 1.5 ¿m with high reflectivity over a 200 nm bandwidth. Two designs are considered; Model 1: a silicon layer with periodic air holes and Model 2: a stacked

Maxwell Kerber; Brian Dick; Mark Fralick; Hugo Jazo; Richard Waters

2009-01-01

79

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

ERIC Educational Resources Information Center

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…

Navratil, Zdenek; Dosoudilova, Lenka; Jurmanova, Jana

2013-01-01

80

Performance and applications of a spectrometer with micromachined scanning grating  

Microsoft Academic Search

Micro Optical Electro Mechanical Systems (MOEMS) gain more and more importance in technical applications. The combination of optical actuators and micromachined silicon technology arise possibilities to realize equipment in high volumes for reasonable prices, that have formerly been expensive laboratory equipment. This paper reports on the performance and applications of a spectrometer in MOEMS technology. It is based on a

Heinrich Grüger; Alexander Wolter; Tobias Schuster; Harald Schenk; Hubert K. Lakner

2003-01-01

81

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

NASA Astrophysics Data System (ADS)

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.

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

2001-07-01

82

Varied-space grazing incidence gratings in high resolution scanning spectrometers  

SciTech Connect

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.

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

1986-10-01

83

Advanced statistical analysis of laser-induced breakdown spectroscopy data to discriminate sedimentary rocks based on Czerny-Turner and Echelle spectrometers  

NASA Astrophysics Data System (ADS)

The correct identification of rock types is critical for understanding the origins and history of any particular rock body. Laser-induced breakdown spectroscopy (LIBS) has developed into an excellent analytical tool for geological materials research because of its numerous technical advantages compared with traditional methods. The coupling of LIBS with advanced multivariate analysis has received increasing attention because it facilitates the rapid processing of spectral information to differentiate and classify samples. In this study, we collected LIBS datasets for 16 sedimentary rocks from Triassic strata in Sichuan Basin. We compared the performance of two types of spectrometers (Czerny-Turner and Echelle) for classification of rocks using two advanced multivariate statistical techniques, i.e., partial least squares discriminant analysis (PLS-DA) and support vector machines (SVMs). Comparable levels of performance were achievable when using the two systems in the best signal reception conditions. Our results also suggest that SVM outperformed PLS-DA in classification performance. Then, we compared the results obtained when using pre-selected wavelength variables and broadband LIBS spectra as variable inputs. They provided approximately equivalent levels of performance. In addition, the rock slab samples were also analyzed directly after being polished. This minimized the analysis time greatly and showed improvement of classification performance compared with the pressed pellets.

Zhu, Xiaoqin; Xu, Tao; Lin, Qingyu; Liang, Long; Niu, Guanghui; Lai, Hongjun; Xu, Mingjun; Wang, Xu; Li, Hua; Duan, Yixiang

84

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

NASA Astrophysics Data System (ADS)

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).

Smith, Randall K.

2014-08-01

85

An infrared high resolution silicon immersion grating spectrometer for airborne and space missions  

NASA Astrophysics Data System (ADS)

Broad-band infrared (IR) spectroscopy, especially at high spectral resolution, is a largely unexplored area for the far IR (FIR) and submm wavelength region due to the lack of proper grating technology to produce high resolution within the very constrained volume and weight required for space mission instruments. High resolution FIR spectroscopy is an essential tool to resolve many atomic and molecular lines to measure physical and chemical conditions and processes in the environments where galaxy, star and planets form. A silicon immersion grating (SIG), 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 for space missions. A prototype SIG high resolution spectrograph, called Florida IR Silicon immersion grating spectromeTer (FIRST), has been developed at UF and was commissioned at a 2 meter robotic telescope at Fairborn Observatory in Arizona. The SIG with 54.74 degree blaze angle, 16.1 l/mm groove density, and 50x86 mm2 grating area has produced R=50,000 in FIRST. The 1.4-1.8 um wavelength region is completely covered in a single exposure with a 2kx2k H2RG IR array. The on-sky performance meets the science requirements for ground-based high resolution spectroscopy. Further studies show that this kind of SIG spectrometer with an airborne 2m class telescope such as SOFIA can offer highly sensitive spectroscopy with R~20,000-30,000 at 20 to 55 microns. Details about the on-sky measurement performance of the FIRST prototype SIG spectrometer and its predicted performance with the SOFIA 2.4m telescope are introduced.

Ge, Jian; Zhao, Bo; Powell, Scott; Jiang, Peng; Uzakbaiuly, Berik; Tanner, David

2014-08-01

86

Concave reflective SU8 photoresist gratings for flat-field integrated spectrometers  

Microsoft Academic Search

On-chip spectrometry will play a leading role in the development of micro-optofluidic systems for analytical chemistry. Integrated spectrometers fabricated using a polymer-on-silicon platform have been designed, fabricated, and characterized. Reflective grating designs have been implemented using a recursive algorithm to calculate the facet positions as described by McGreer [Appl. Opt. 35, 5904 (1996)]. It is shown that the free spectral

Dan A. Zauner; Anders M. Jorgensen; Thomas A. Anhoj; Jörg Hübner

2006-01-01

87

High resolution hadamard transform spectrometer.  

PubMed

The ir spectrometer described employs alkaline halide lenses, an echelle grating, and a cryogenically cooled doped germanium bolometer as a detector. It is provided for two possible modes of operation: one is a single slit or conventional scan, the other is a multiplex or Hadamard scan. Signal strength, noise characteristics, scanning time, and available computer facilities determine the mode of operation. Sample spectra are presented. PMID:20111540

Hansen, P; Strong, J

1972-03-01

88

Aberration analysis of a concentric imaging spectrometer with a convex grating  

NASA Astrophysics Data System (ADS)

We analyze the ray-optical aberrations in a concentric imaging spectrometer composed of one convex grating and two concave mirrors of different radii. We assume that the system is generally not telecentric. First we derive aberration functions of Seidel and Buchdahl types for a bundle of rays converging to dispersed Gaussian images. Next we discuss the conditions in which the third and fifth-order ray aberrations are balanced. Finally we show that a concentric imaging spectrometer for use with a CCD detector can be optimized effectively in the neighborhood of a stigmatic condition. The stigmatic condition derived here can be useful in rapidly creating an initial design of a concentric imaging spectrometer with minimal aberrations.

Kim, Seo Hyun; Kong, Hong Jin; Chang, Soo

2014-12-01

89

Optimizing and characterizing grating efficiency for a soft X-ray emission spectrometer.  

PubMed

The efficiency of soft X-ray diffraction gratings is studied using measurements and calculations based on the differential method with the S-matrix propagation algorithm. New open-source software is introduced for efficiency modelling that accounts for arbitrary groove profiles, such as those based on atomic force microscopy (AFM) measurements; the software also exploits multi-core processors and high-performance computing resources for faster calculations. Insights from these calculations, including a new principle of optimal incidence angle, are used to design a soft X-ray emission spectrometer with high efficiency and high resolution for the REIXS beamline at the Canadian Light Source: a theoretical grating efficiency above 10% and resolving power E/?E > 2500 over the energy range from 100 eV to 1000 eV are achieved. The design also exploits an efficiency peak in the third diffraction order to provide a high-resolution mode offering E/?E > 14000 at 280 eV, and E/?E > 10000 at 710 eV, with theoretical grating efficiencies from 2% to 5%. The manufactured gratings are characterized using AFM measurements of the grooves and diffractometer measurements of the efficiency as a function of wavelength. The measured and theoretical efficiency spectra are compared, and the discrepancies are explained by accounting for real-world effects: groove geometry errors, oxidation and surface roughness. A curve-fitting process is used to invert the calculations to predict grating parameters that match the calculated and measured efficiency spectra; the predicted blaze angles are found to agree closely with the AFM estimates, and a method of characterizing grating parameters that are difficult or impossible to measure directly is suggested. PMID:23412484

Boots, Mark; Muir, David; Moewes, Alexander

2013-03-01

90

Arcus:An X-ray Grating Spectrometer on the ISS: Mission Overview  

NASA Astrophysics Data System (ADS)

Arcus is an X-ray grating spectrometer mission to be deployed on the International Space Station in response to NASA’s Astrophysics Division plan to announce a SMEX call in Fall 2014 with a cost cap of $125M (FY15). The baseline design uses sub-apertured X-ray silicon pore optics feeding into off-plane gratings to achieve both high spectral resolution with a large effective area. The detector focal plane uses Suzaku-type CCDs. The mission would be ready to be launched and mounted on the ISS in 2020. The mission parameters are R=2800 and ~800 sq. cm at the critical O VII wavelength near 21Å 0.5 keV), with an overall bandpass from 8-52Å (0.25-1.5 keV), enabling a wide range of science objectives. These values are similar to those of the grating spectrometers considered as part of the proposed Constellation-X and IXO missions, which were highly ranked by two Decadal surveys.

Bookbinder, Jay A.

2014-08-01

91

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

NASA Astrophysics Data System (ADS)

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 8-52Å (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).

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

92

Development of a Novel Breast Cancer Detector based on Improved Holography Concave Grating Imaging Spectrometer  

NASA Astrophysics Data System (ADS)

Breast cancer can be detected by B-mode ultrasonic imaging, X-mammography, CT imaging, and MRI. But some drawbacks existed in these methods, their applications was limited in some certain. So, a novel high resolution breast cancer detector (BCD) is developed in this paper. Meanwhile, an improved holography concave grating imaging spectrometer (HCGIS) is designed. In this HCGIS, the holography concave grating is used as the diffraction grating. Additionally, CCD with combined image acquisition (IAQ) card and the 3D scan platform are used as the spectral image acquisition component. This BCD consists of the light source unit, light-path unit, check cavity, splitting-light unit, spectrum acquisition and imaging unit, signal processing unit, computer and data analysis software unit, etc. Experimental results show that the spectral range of the novel BCD can reach 300-1000 nm, its wavelength resolution can reach 1nm, and this system uses the back-split-light technology and the splitting-light structure of holography concave grating. Compared with the other instruments of breast cancer detection, this BCD has many advantages, such as, compacter volume, simpler algorithm, faster processing speed, higher accuracy, cheaper cost and higher resolution, etc. Therefore, this BCD will have the potential values in the detection of breast disease.

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

2011-01-01

93

Design of spherical varied line-space gratings for a high-resolution EUV spectrometer  

NASA Technical Reports Server (NTRS)

A highly efficient EUV spectrograph is designed for high-resolution spectroscopic observation. The spectrograph is designed for point source astronomy in a 40-120 nm bandpass and is to be ORFEUS (Orbiting Retrievable Far and Extreme Ultraviolet Spectrometer), scheduled for launch as the first payload of a German space platform Astro-SPAS (Astronomy Shuttle Pallet Satellite). The design uses spherical varied line-space (SVLS) grating to minimize astigmatism, coma, and spherical aberration. The effectiveness and practical feasibility of the design is proved by an SVLS grating for visible use. The image focusing properties of the SVLS grating for ORFEUS are compared to those with toroidal uniform line-space (TULS) design. The SVLS design is superior to the TULS, theoretically in resolution and image concentration, but also practically with not only fabrication ease. Four SVLS gratings with nominal groove densities of 6000, 4550, 3450, and 2616 gr./mm, and a 200 mm x 200 mm ruled area have been ruled using a numerically controlled ruling engine for use in ORFEUS.

Harada, Tatsuo; Kita, Toshiaki; Bowyer, Stuart; Hurwitz, Mark

1991-01-01

94

A compact immersion grating spectrometer with quantum capacitance detectors for space- borne far-IR spectroscopy  

NASA Astrophysics Data System (ADS)

We will develop a wafer-scale moderate-resolution (R~500) wideband immersion waveguide grating spectrometer with an integrated quantum capacitance detector (QCD) array to demonstrate a background-limited wideband spectrometer with detectors on a silicon wafer. Such a system is required for future cryogenic far-IR missions for which spectrometer scope is typically limited by cryogenic size and mass. This effort builds on the successes with the waveguide grating spectrometer technology (WaFIRS) as used in Z-Spec, as well as the recent demonstration of a world-record optical NEP in the far-IR of 2x10^-20W/Hz1/2 with the QCD. Here we will use silicon immersion to reduce the volume and mass by at least an order of magnitude. Unlike spectrometers based on superconducting transmission line or waveguide which are limited to frequencies below the 720 GHz niobium gap (e.g. SuperSpec and Microspec), the WaFIRS / QCD technology is applicable throughout the far-IR / THz. The Quantum Capacitance Detector is a small-volume superconducting device that exploits it s extreme susceptibility to the presence of quasiparticle excitations arising from pair-breaking radiation to enable background limited detection. With recent world-record NEP demonstrations, it is arguably the most promising device for low optical background loads 10^-22 through 10^-16W that are encountered in dispersed spectroscopy at space-borne and balloon-borne platforms. Our prototype will target the 200- 350 micron band, it will provide R~500 with a ~500 QCD pixel array. Optical characterization will verify system sensitivity, spectral performance, and beam characteristics.

Echternach, Pierre

95

Calibration and in orbit performance of the reflection grating spectrometer onboard XMM-Newton  

E-print Network

Context: XMM-Newton was launched on 10 December 1999 and has been operational since early 2000. One of the instruments onboard XMM-Newton is the reflection grating spectrometer (RGS). Two identical RGS instruments are available, with each RGS combining a reflection grating assembly (RGA) and a camera with CCDs to record the spectra. Aims: We describe the calibration and in-orbit performance of the RGS instrument. By combining the preflight calibration with appropriate inflight calibration data including the changes in detector performance over time, we aim at profound knowledge about the accuracy in the calibration. This will be crucial for any correct scientific interpretation of spectral features for a wide variety of objects. Methods: Ground calibrations alone are not able to fully characterize the instrument. Dedicated inflight measurements and constant monitoring are essential for a full understanding of the instrument and the variations of the instrument response over time. Physical models of the instru...

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

2014-01-01

96

High Resolution Transmission Grating Spectrometer for Edge Toroidal Rotation Measurements of Tokamak Plasmas  

SciTech Connect

We present a high throughput (f/3) visible (3500 - 7000 Angstrom) Doppler spectrometer for toroidal rotation velocity measurements of the Alcator C-Mod tokamak plasma. The spectrometer has a temporal response of 1 ms and a rotation velocity sensitivity of {approx}10{sup 5} cm/s. This diagnostic will have a tangential view and map out the plasma rotation at several locations along the outer half of the minor radius (r/a > 0.5). The plasma rotation will be determined from the Doppler shifted wavelengths of D{sub alpha} and magnetic and electric dipole transitions of highly ionized impurities in the plasma. The fast time resolution and high spectral resolving power are possible due to a 6' diameter circular transmission grating that is capable of {lambda}/{Delta}{lambda} {approx} 15500 at 5769 Angstrom in conjunction with a 50 {micro}m slit.

Graf, A; May, M; Beiersdorfer, P; Magee, E; Lawrence, M; Terry, J; Rice, J

2004-04-29

97

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

SciTech Connect

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.

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

98

Study of Planck’s law with a small USB grating spectrometer  

NASA Astrophysics Data System (ADS)

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 measurement techniques (e.g. with the measurement of filament temperature from the temperature dependence of filament resistance). We have shown that even spectrometers with a limited wavelength range may be successfully used to study the Planck distribution. The temperature obtained from the fit of Planck’s law to the measured spectra was, within the uncertainty, close to the results of comparative techniques.

Navrátil, Zden?k; Dosoudilová, Lenka; Jurmanová, Jana

2013-05-01

99

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

100

Reduction of polarization-induced artifacts in grating-based spectrometers.  

PubMed

An optical device that converts unpolarized light into a single polarization state is described. The device is based on a polarizing beam splitter that separates the two polarization directions. The beam splitter is combined with two pairs of equilateral prisms that are used to collimate the two beams in terms of both propagation and polarization directions. When it is used in combination with a blazed diffraction grating, this device is shown to effectively remove the polarization dependence of the first-order diffracted power. The device has an insertion loss of approximately 14% for purely s-polarized light. However, for unpolarized light incident upon the two gratings studied here, the increased throughput of the p-polarized component leads to an average relative gain in overall efficiency of 13%-19%, depending on the grating. In collimating the two polarization directions, the device may cause a reduction in spectral resolution for a rectangular entrance slit. As a result, the device is more likely to find use in spectrometers that have a circular aperture, such as that provided by an optical fiber. PMID:16237926

Kho, Kiang Wei; Stoddart, Paul R; Rosman, Gavan; Harris, Martin; Mazzolini, Alex

2005-10-10

101

Developments of the off-plane x-ray grating spectrometer for IXO  

NASA Astrophysics Data System (ADS)

The International X-ray Observatory (IXO) is a collaborative effort between NASA, ESA, and JAXA. The IXO science goals are heavily based on obtaining high quality X-ray spectra. In order to achieve this goal the science payload will incorporate an array of gratings for high resolution, high throughput spectroscopy at the lowest X-ray energies, 0.3 - 1.0 keV. The spectrometer will address a number of important astrophysical goals such as studying the dynamics of clusters of galaxies, determining how elements are created in the explosions of massive stars, and revealing most of the "normal" matter in the universe which is currently thought to be hidden in hot filaments of gas stretching between galaxies. We present here a mature design concept for an Off-Plane X-ray Grating Spectrometer (OP-XGS). This XGS concept has seen recent significant advancements in optical and mechanical design. We present here an analysis of how the baseline OP-XGS design fulfills the IXO science requirements for the XGS and the optical and mechanical details of this design.

McEntaffer, R. L.; Murray, N. J.; Holland, A. D.; Tutt, J.; Barber, S. J.; Harriss, R.; Schultz, T.; Casement, S.; Lillie, C.; Dailey, D.; Johnson, T.; Danner, R.; Cash, W.; Zeiger, B.; Shipley, A.; Page, M.; Walton, D.; Pool, P.; Endicott, J.; Willingale, D.

2010-07-01

102

[Development of spectrometer for tongue diagnosis based on plane holography concave grating].  

PubMed

The traditional tongue inspection method should be urgently improved due to the relative large diagnosis error probability caused by the excessive dependence on the Chinese physician's experience and judgment. But the application of tongue diagnosis based on image processing is limited by some factors including the performance of light source, image acquisition device and the low recognition rate of similar color for different diseases. In order to overcome these drawbacks, the spectroscopy method was employed to analyze the tongue by using the unique fingerprint effect of tongue spectrum. A spectrometer for tongue diagnosis (STD) was developed to achieve this goal in this paper. Meanwhile, to overcome the shortcomings of traditional light-splitting devices, a plane holographic concave grating was used as the diffractive grating, which not only can improve the luminous flux efficiency and miniaturize system, but also improve the spectral imaging quality and resolution. Experimental results demonstrated that the spectral range of STD reached 340-850 nm, and its spectral resolution is better than 2 nm. And the result of simulation experiment validated the feasibility of spectrometer's system. PMID:24369678

Ren, Zhong; Liu, Guo-dong; Huang, Zhen

2013-09-01

103

EGRAM- ECHELLE SPECTROGRAPH DESIGN AID  

NASA Technical Reports Server (NTRS)

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.

Dantzler, A. A.

1994-01-01

104

High-resolution spectroscopy using an echelle spectrometer with predisperser-II. Analytical optimization for inductively coupled plasma atomic emission spectrometry1  

NASA Astrophysics Data System (ADS)

This work is primarily concerned with the optimization of the slit width (and thus the practical resolving power) of a new type of echelle spectrometer coupled to a 50-MHz ICP operated with a pneumatic nebulizer, as described in Part I of this article series (Spectrochim. Acta39B, this issue (1984)). The optimization is carried out under "ICP compromise conditions" and uses detection power as criterion. With a "pure water" matrix, the effects of slit width on net line and background signals, signal-to-background ratio (SBR), relative standard deviation (RSD) of background signal and detection limit were evaluated for a set of prominent ICP lines spread over wavelengths between 190 and 500 nm. The detection limits eventually attained under optimum conditions were an order of magnitude better than "standard" values reported in the literature (winge et al., Appl. Spectrosc.33, 206 (1979)). The optimization was extended to a Ni-Co matrix, the latter serving as an example of samples that emit line-rich spectra. In this context, a detailed analysis was made of the background enhancements associated with the presence of major elements that emit line-rich spectra. Accordingly the effects of slit width on SBR, background RSD and detection limit were differentiated in dependence on whether the background enhancement was due to quasicontinuous background, due to complete coincidence of the analysis line with a line of the matrix, or due to partial line overlap. The quasi-continuous background was attributed to the wings of strong lines of the matrix, as described in Part III ( Spectrochim. Acta39B, this issue (1984)). It was established that with pure line wing interference the gain in detection power achieved by improving the practical spectral bandwidth from, say, 0.015-0.005 nm is approximately similar to that found for pure water, that is, a factor of 2-3. In the case of partial line overlap, larger improvements can be achieved depending on the physical widths of the lines involved and the wavelength distance between them. The paper includes a description of a computer technique for manipulating experimental spectral scans stored on floppy disks. This technique is used to simulate scans of solutions of matrices spiked with analytes using only the scans for the pure matrix, the pure analyte and the pure solvent. Various examples are detailed in connection with the question whether and to which extent high resolution does improve the accuracy of trace analysis in the case of partial line overlap. Preliminary tests led to the thesis that high resolution is capable of providing higher accuracy than medium resolution at the same ratio of the concentration present to the detection limit. If this thesis can be definitely substantiated in future work, this means that high resolution not only provides for better detection limits, but will also yield higher accuracy at lower concentrations than medium resolution, the latter advantage being associated in particular with samples than emit line-rich spectra.

Boumans, P. W. J. M.; Vrakking, J. J. A. M.

105

A MEMS-based resonant-scanning lamellar grating Fourier transform micro-spectrometer with laser reference system  

Microsoft Academic Search

A lamellar grating Fourier transform infra-red (FTIR) micro-spectrometer is presented in which the device is electromagnetically actuated in resonant mode so as to achieve larger displacements with a lower driving voltage. By actuating at resonance, we can also have a design with a higher spring stiffness design such that the micro-spectrometer will have little influence from external perturbation. A data

Feiwen Lee; Guangya Zhou; Hongbin Yu; Fook Siong Chau

2009-01-01

106

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

NASA Astrophysics Data System (ADS)

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. 539-540, 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).

Yoshida, Hiroyuki

2013-10-01

107

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

PubMed

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

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

2012-04-01

108

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

SciTech Connect

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.

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

109

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

SciTech Connect

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.

Moore, A. S.; Guymer, T. M.; Morton, J.; Bentley, C.; Stevenson, M. [Directorate Science and Technology, AWE Aldermaston, Reading, RG7 4PR (United Kingdom); Kline, J. L.; Taccetti, M.; Lanier, N. E.; Workman, J.; Peterson, B.; Mussack, K.; Cowan, J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Prasad, R.; Richardson, M.; Burns, S.; Kalantar, D. H.; Benedetti, L. R.; Bell, P.; Bradley, D.; Hsing, W. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States)

2012-10-15

110

Calibration and in-orbit performance of the reflection grating spectrometer onboard XMM-Newton  

NASA Astrophysics Data System (ADS)

Context. XMM-Newton was launched on 10 December 1999 and has been operational since early 2000. One of the instruments onboard XMM-Newton is the reflection grating spectrometer (RGS). Two identical RGS instruments are available, with each RGS combining a reflection grating assembly and a camera with charge-coupled devices to record the spectra. Aims: We describe the calibration and in-orbit performance of the RGS instrument. By combining the preflight calibration with appropriate inflight calibration data including the changes in detector performance over time, we aim at profound knowledge about the accuracy in the calibration. This will be crucial for any correct scientific interpretation of spectral features for a wide variety of objects. Methods: Ground calibrations alone are not able to fully characterize the instrument. Dedicated inflight measurements and constant monitoring are essential for a full understanding of the instrument and the variations of the instrument response over time. Physical models of the instrument are tuned to agree with calibration measurements and are the basis from which the actual instrument response can be interpolated over the full parameter space. Results: Uncertainties in the instrument response have been reduced to <10% for the effective area and <6 mÅ for the wavelength scale (in the range from 8 Å to 34 Å). The remaining systematic uncertainty in the detection of weak absorption features has been estimated to be 1.5%. Conclusions: Based on a large set of inflight calibration data and comparison with other instruments onboard XMM-Newton, the calibration accuracy of the RGS instrument has been improved considerably over the preflight calibrations.

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

2015-01-01

111

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

NASA Astrophysics Data System (ADS)

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.

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

112

A computer program for the collection, reduction and analysis of echelle spectra  

NASA Astrophysics Data System (ADS)

This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta Part B (SAB). The hardcopy text, comprising the main article and an appendix, is accompanied by a disk containing the compiled program, a manual, the source code and tutorial in ASCII format, and data files. The work presented is a result of the need to facilitate collection, calibration, and extraction of data from an echelle spectrometer employing charge coupled array detection (CCD). A computer program, written using Microsoft's BASIC Professional Development System version 7.1 under MS DOS, is explained and demonstrated. Wavelength calibration requires critical spectrometer dimensions, grating counter settings, and the identification of a single spectral line. Calibration accuracies are better than ± 1 pixel across a 576 × 384 pixel array. Extraction of intensity-normalized spectra for all detected orders requires less than 3 min on a 33 MHz 80386 personal computer with an 80387 math coprocessor.

Miller, Duane L.; Scheeline, Alexander

1993-07-01

113

Design of a novel multi-spectral imaging spectrometer for breast cancer detector based on VHT grating  

NASA Astrophysics Data System (ADS)

The ultrasonic imaging, X-mammography, CT imaging and MRI can be applied into the breast cancer diagnosis(BCD). But some factors such as the spatial resolution, contrast and price-performance ratio (PPR) limit their applications. So, a novel BCD technology, that is, multi-spectral imaging is adopted into this paper. It can get more information of the breast tumor and higher identity because it combines the advantages of the spectroscopy and the imaging technology. And in this paper, the multi-spectral light source induced the breast cancer imaging detector(BCID) is designed, the spectrum can cover from the UV to NIR. Meanwhile, a custom-built multi-spectral imaging spectrometer (MSIS) is also developed. And, in order to overcome the stray-light of the light-route system and improve the resolution and light-passing efficiency of the system, the novel volume holography transmissive (VHT) grating instead of the plane or concave grating is used as the diffraction grating in this MSIS. Experimental result show that the novel BCD technology is feasible, it can offer not only the spectral information but also the image of the tumor. The spectrum resolution of the MSIS for BCID based on VHT grating can reach 2nm. Compared with the others, this BCID has more compact structure, faster speed, higher PPR and higher resolution and accuracy. Therefore, this BCID has the potential value in the field of the BCD.

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

2011-06-01

114

Reflection grating spectrometer for the x-ray multi-mirror (XMM) space observatory: design and calculated performance  

SciTech Connect

A spectrometer design candidate is presented for the X-ray Multi-Mirror (XMM) observatory, being planned by the European Space Agency (ESA) as a long-lived large-area of telescopes. The science requirement of moderate resolution (E/..delta..E approx.100) spectroscopy in a two octave region (0.5 to 2 keV) with extremely high throughput (effective area > 500 cm/sup 2/) results in the use of grazing incidence reflection gratings. Due to the low image quality of the telescopes (approx. 1 minute of arc), the grating dispersion must be maximized by use of the classical grating mount in which the spectrum is dispersed within the plane of incident radiation. Due to the small field of view by the x-ray telescopes, the gratings must be situated in the converging beam at the exit of the telescope. A spectrometer module consists of a thin-foil conical mirror telescope, a stack of plane varied-space reflection gratings and an imaging proportional counter. This system is analyzed on the basis of dispersion, geometric aberrations and efficiency. At a spectral resolution of 0.15 A, a twenty module XMM would attain an average effective area of approx.900 cm/sup 2/, reaching twice this value at the peak wavelength (15 A). Similar throughput is obtained in second order centered at 7.5 A, the two spectral orders separated by the non-dispersive energy resolution of the proportional counter. Continuous spectra are obtained in the 6-25 A band (0.5 to 2 keV), and can be extended to 45 A if desired by tuning of the grating. The instrument sensitivity is sufficient to allow the first spectral detection of soft x-ray features in external galaxies, with access to an estimated population of several hundred active galactic nuclei. Such observations will expand vastly the roles feasible for spectroscopy in x-ray astrophysics, marking the beginning of a new era in space astronomy.

Hettrick, M.C.; Kahn, S.M.

1985-10-01

115

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

SciTech Connect

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.

Reverdin, Charles; Caillaud, T.; Gilleron, F.; Pain, J. C.; Silvert, V.; Soullie, G.; Villette, B. [CEA, DAM, DIF, 91297 Arpajon (France); Thais, Frederic; Loisel, Guillaume; Blenski, T.; Poirier, M. [CEA, DSM, IRAMIS, Service Photons, Atomes et Molecules, 91191 Gif-sur-Yvette (France); Busquet, M. [ARTEP Inc, Ellicott City, Maryland 21042 (United States); Bastiani-Ceccotti, S.; Serres, F. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France); Ducret, J. E. [CELIA, UMR5107, CEA, CNRS, Universite de Bordeaux, 33400 Talence (France); Foelsner, W. [Max Planck Instituet fuer Quantum Optik, 85748 Garching (Germany); Gilles, D.; Turck-Chieze, S. [CEA, DSM, IRFU, Service d'astrophysique, 91191 Gif-sur-Yvette (France)

2012-10-15

116

Grating arrays for high--throughput soft X-ray spectrometers A. Rasmussena A. Aquilab j BookbinderC C. Chang E. Gulliksonb R. Heilmanne  

E-print Network

Address: 550 West 120 Street, New York, NY 10027 Optics for EUV, X-Ray, and Gamma-Ray Astronomy, editedGrating arrays for high--throughput soft X-ray spectrometers A. Rasmussena A. Aquilab j BookbinderColumbja Astrophysics Lab, 550 West 120th Street, New York, New York, USA bCenter for X-ray Optics, Lawrence Berkeley

117

Post-SM4 Sensitivity Calibration of the STIS Echelle Modes  

NASA Astrophysics Data System (ADS)

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.

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

2012-01-01

118

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)

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.

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

2003-01-01

119

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)

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.

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

2003-01-01

120

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

SciTech Connect

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.

Kowalski, Michael P. [Naval Research Laboratory, Washington, D.C. 20375 (United States); Barbee, Troy W. Jr. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Heidemann, Klaus F. [Carl Zeiss, D-73446, Oberkochen, (Germany); Gursky, Herbert [Naval Research Laboratory, Washington, D.C. 20375 (United States); Rife, Jack C. [Naval Research Laboratory, Washington, D.C. 20375 (United States); Hunter, William R. [SFA Incorporated, 1401 McCormick Drive, Largo, Maryland 20774 (United States); Fritz, Gilbert G. [Naval Research Laboratory, Washington, D.C. 20375 (United States); Cruddace, Raymond G. [Naval Research Laboratory, Washington, D.C. 20375 (United States)

1999-11-01

121

Comparison lamps automation CTIO 60 inches Echelle  

E-print Network

Comparison lamps automation CTIO 60 inches Echelle ECH60S5.1 La Serena, December 09, 2009 #12)...............................................................................12 CTIO 60 inches Echelle / Comparison lamps automation, ECH60S5.1 2 #12;Introduction The present document is just a brief summary of the work done automating the 60 inches echelle comparison lamps

Tokovinin, Andrei A.

122

Silicon immersion gratings and their spectroscopic applications  

NASA Astrophysics Data System (ADS)

Silicon immersion gratings (SIGs) offer several advantages over the commercial echelle gratings for high resolution infrared (IR) spectroscopy: 3.4 times the gain in dispersion or ~10 times the reduction in the instrument volume, a multiplex gain for a large continuous wavelength coverage and low cost. We present results from lab characterization of a large format SIG of astronomical observation quality. This SIG, with a 54.74 degree blaze angle (R1.4), 16.1 l/mm groove density, and 50x86 mm2 grating area, was developed for high resolution IR spectroscopy (R~70,000) in the near IR (1.1-2.5 ?m). Its entrance surface was coated with a single layer of silicon nitride antireflection (AR) coating and its grating surface was coated with a thin layer of gold to increase its throughput at 1.1-2.5 ?m. The lab measurements have shown that the SIG delivered a spectral resolution of R=114,000 at 1.55 ?m with a lab testing spectrograph with a 20 mm diameter pupil. The measured peak grating efficiency is 72% at 1.55 ?m, which is consistent with the measurements in the optical wavelengths from the grating surface at the air side. This SIG is being implemented in a new generation cryogenic IR spectrograph, called the Florida IR Silicon immersion grating spectrometer (FIRST), to offer broad-band high resolution IR spectroscopy with R=72,000 at 1.4-1.8 um under a typical seeing condition in a single exposure with a 2kx2k H2RG IR array at the robotically controlled Tennessee State University 2-meter Automatic Spectroscopic Telescope (AST) at Fairborn Observatory in Arizona. FIRST is designed to provide high precision Doppler measurements (~4 m/s) for the identification and characterization of extrasolar planets, especially rocky planets in habitable zones, orbiting low mass M dwarf stars. It will also be used for other high resolution IR spectroscopic observations of such as young stars, brown dwarfs, magnetic fields, star formation and interstellar mediums. An optimally designed SIG of the similar size can be used in the Silicon Immersion Grating Spectrometer (SIGS) to fill the need for high resolution spectroscopy at mid IR to far IR (~25-300 ?m) for the NASA SOFIA airborne mission in the future.

Ge, Jian; Zhao, Bo; Powell, Scott; Fletcher, Adam; Wan, Xiaoke; Chang, Liang; Jakeman, Hali; Koukis, Dimitrios; Tanner, David B.; Ebbets, Dennis; Weinberg, Jonathan; Lipscy, Sarah; Nyquist, Rich; Bally, John

2012-09-01

123

Electrically-programmable diffraction grating  

DOEpatents

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).

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

1998-01-01

124

Path-folded infrared spectrometer consisting of 10 sub-gratings and a two-dimensional InGaAs detector.  

PubMed

A new compact infrared spectrometer without any mechanical moving elements has been designed and constructed using a two-dimensional InGaAs array detector and 10 sub-gratings. The instrument is compact, with a double-folded optical path configuration. The spectra are densely 10-folded to achieve 0.07-nm spectral resolution and a 2-ms data acquisition time in the 1450- to 1650-nm wavelength region, making the instrument useful for real-time spectroscopic data analyses in optical communication and many other fields. PMID:19687974

Liu, Ming-Hui; Pan, Su-Xing; Chen, Yu-Rui; Wu, Yun-Fei; Cai, Qing-Yuan; Mao, Peng-Hui; Zheng, Yu-Xiang; Chen, Liang-Yao

2009-08-17

125

Investigation and characterization of high-efficient NIR-scanning gratings used in NIR micro-spectrometer  

Microsoft Academic Search

Spectroscopy in the infrared region is today an important application to measure, control and investigate liquids or gases in industrial, medical or environmental applications. We have developed a small, transportable NIRspectrometer with a size of only 120 x 80 x 80 mm3, and a MOEMS-scanning-grating chip as main element. The scanning-grating chip is resonantly driven by a pulsed voltage of

F. Zimmer; A. Heberer; Th. Sandner; H. Grueger; H. Schenk; H. Lakner; A. Kenda; W. Scherf

2007-01-01

126

A radial velocity spectrometer for the Automated Planet Finder Telescope at Lick Observatory  

NASA Astrophysics Data System (ADS)

The Ken and Gloria Levy Spectrometer is being constructed at the Instrument Development Laboratory (Technical Facilities) of UCO/ Lick Observatory for use on the 2.4 meter Automated Planet Finder Telescope at Mt. Hamilton. The mechanical design of the instrument has been optimized for precision Doppler measurements. A key component of the design is the space-frame structure that contains passive thermal compensation. Determinate hexapod structures are used to mount the collimator, prism, and echelle grating. In this paper we describe the instrument mechanical design and some features that will help it detect rocky planets in the habitable zone.

Radovan, Matthew V.; Cabak, Gerald F.; Laiterman, Lee H.; Lockwood, Christopher T.; Vogt, Steven S.

2010-07-01

127

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

NASA Astrophysics Data System (ADS)

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.

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

2011-09-01

128

High-resolution spectrometer: solution to the axial resolution and ranging depth trade-off of SD-OCT  

NASA Astrophysics Data System (ADS)

We demonstrate a cross-dispersed spectrometer for Spectral Domain Optical Coherence Tomography (SD-OCT). The resolution of a conventional SD-OCT spectrometer is limited by the available sizes of the linear array detectors. The adverse consequences of this finite resolution is a trade-off between achieving practical field of view (i.e. ranging depth) and maintaining high axial resolution. Inspired by spectrometer designs for astronomy, we take advantage of very high pixel-density 2D CCD arrays to map a single-shot 2D spectrum to an OCT A-scan. The basic system can be implemented using a high-resolution Echelle grating crossed with a prism in a direction orthogonal to the dispersion axis. In this geometry, the interferometric light returning from the OCT system is dispersed in two dimensions; the resulting spectrum can achieve more pixels than a traditional OCT spectrometer (which increases the ranging depth) and maintains impressive axial resolution because of the broad bandwidth of the detected OCT light. To the best of our knowledge, we present the first demonstration of OCT data using an Echelle-based cross-dispersed spectrometer. Potential applications for such a system include high-resolution imaging of the retina or the anterior segment of the eye over extended imaging depths and small animal imaging.

Marvdashti, Tahereh; Lee, Hee Yoon; Ellerbee, Audrey K.

2013-03-01

129

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

130

Electrically-programmable diffraction grating  

DOEpatents

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.

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

1998-05-26

131

The Accretion Disk Corona and Disk Atmosphere of 4U 1624-490 as Viewed by the Chandra-High Energy Transmission Grating Spectrometer  

NASA Astrophysics Data System (ADS)

We present a detailed spectral study (photoionization modeling and variability) of the "Big Dipper" 4U 1624-490 based on a Chandra-High Energy Transmission Grating Spectrometer (HETGS) observation over the ~76 ks binary orbit of 4U 1624-490 . While the continuum spectrum can be modeled using a blackbody plus power law, a slightly better fit is obtained using a single ? = 2.25 power-law partially (71%) covered by a local absorber of column density N_H Local=8.1_{-0.6}^{+0.7}× 10^{22} cm^{-2}. The data show a possible quasi-sinusoidal modulation with period 43+13 -9 ks that might be due to changes in local obscuration. Photoionization modeling with the XSTAR code and variability studies of the observed strong Fe XXV and Fe XXVI absorption lines point to a two-temperature plasma for their origin: a highly ionized component of ionization parameter ?hot ? 104.3 erg cm s-1 (T ~ 3.0 × 106 K) associated with an extended accretion disk corona of radius R ~ 3 × 1010 cm, and a less-ionized more variable component of ? ? 103.4 erg cm s-1 (T ~ 1.0 × 106 K) and ? ? 10^{3.1} erg cm s^{-1} (T ~ 0.9 × 106 K) coincident with the accretion disk rim. We use this, with the observed Fe XXV and Fe XXVI absorption line variations (in wavelength, strength, and width) to construct a viewing geometry that is mapped to changes in plasma conditions over the 4U 1624-490 orbital period.

Xiang, Jingen; Lee, Julia C.; Nowak, Michael A.; Wilms, Jörn; Schulz, Norbert S.

2009-08-01

132

IR spectrometers for Venus and Mars measurements  

NASA Astrophysics Data System (ADS)

The SOIR spectrometer [1] is an infra-red spectrometer that has performed over 500 solar occultation measurements of the Venus atmosphere, profiling major and minor constituents and studying aerosol absorption, temperature and pressure effects. NOMAD is a 3-channel spectrometer for Mars occultation, limb and nadir measurements. 2 channels are infra-red, the other UV-visible. We will present the technology that enables SOIR and NOMAD to get to parts per billion mixing ratio sensitivities for trace atmospheric components and highlight the improvements made to the SOIR design to enable nadir viewing with NOMAD. Key components include the Acousto-Optical Tunable Filter with radio frequency driver that allows these spectrometers to select the wavelength domain under observation with no need for mechanical moving parts. It also allows background measurements because it is opaque when no RF is applied. The grating with 4 grooves/mm is a very hard to manufacture optical component, and suppliers were very difficult to find. The detector-cooler combination (working at 90K) is from Sofradir/Ricor and the model on board Venus Express is still working after 6 years in space (more on/off cycles that ON hour lifetime problem). The detector MCT mix is slightly altered for nadir observation, in order to reduce thermal background noise and the nadir channel spectrometer is cooled down to 173K by a large V-groove radiator. All the optical components have been enlarged to maximise signal throughput and the slit (that determines spatial and spectral resolution) has also been increased. The spacecraft attitude control system switches from yaw steering for nadir to inertial pointing for solar occultations. 1. Nevejans, D., E. Neefs, E. Van Ransbeeck, S. Berkenbosch, R. Clairquin, L. De Vos, W. Moelans, S. Glorieux, A. Baeke, O. Korablev, I. Vinogradov, Y. Kalinnikov, B. Bach, J.P. Dubois, and E. Villard, Compact high-resolution space-borne echelle grating spectrometer with AOTF based on order sorting for the infrared domain from 2.2 to 4.3 micrometer. Applied Optics, 45(21), 5191-5206 (2006)

Drummond, Rachel; Neefs, Eddy; Vandaele, Ann C.

2012-07-01

133

The FIRE infrared spectrometer at Magellan: construction and commissioning  

E-print Network

We describe the construction and commissioning of FIRE, a new 0.8-2.5?m echelle spectrometer for the Magellan/ Baade 6.5 meter telescope. FIRE delivers continuous spectra over its full bandpass with nominal spectral ...

Simcoe, Robert A.

134

The Spectrometer  

ERIC Educational Resources Information Center

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…

Greenslade, Thomas B., Jr.

2012-01-01

135

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

NASA Astrophysics Data System (ADS)

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 ?m 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.

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

2014-07-01

136

GHRS Cycle 5 Echelle Wavelength Monitor  

NASA Astrophysics Data System (ADS)

This proposal defines the spectral lamp test for Echelle A. It is an internal test which makes measurements of the wavelength lamp SC2. It calibrates the carrousel function, Y deflections, resolving power, sensitivity, and scattered light. The wavelength calibration dispersion constants will be updated in the PODPS calibration data base. This proposal defines the spectral lamp test for Echelle B. It is an internal test which makes measurements of the wavelength lamp SC2. It calibrates the carrousel function, Y deflections, resolving power, sensitivity, and scattered light. The wavelength calibration dispersion constants will be updated in the PODPS calibration data base. It will be run every 4 months. The wavelengths may be out of range according to PEPSI or TRANS. Please ignore the errors.

Soderblom, David

1995-07-01

137

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)

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.

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

138

Electromagnetic diffraction efficiencies for plane reflection diffraction gratings  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

139

Stretchable diffraction gratings for spectrometry.  

PubMed

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

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

2007-07-23

140

Stretchable diffraction gratings for spectrometry  

NASA Astrophysics Data System (ADS)

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.

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

2007-07-01

141

NRES: The Network of Robotic Echelle Spectrographs  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

142

Feasibility study into the use of a micro-machined grating spectrometer to measure fat and protein content in liquid milk products  

Microsoft Academic Search

A study was undertaken to determine the feasibility of building a system capable of measuring the protein and fat content in dairy based samples. The system would be based upon a micro-spectrometer. Using Beers–Lambert law, spectral absorption changes due to protein and fat variation in dairy samples are obtained, over the spectral region 800 to 1100 nm. Samples representing a

Desmond Brennan; John Alderman; Barry O'Connor

1999-01-01

143

EUV properties of two diffraction gratings  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

144

Design and simulation of microspectrometer based on torsional MEMS grating  

Microsoft Academic Search

Micro-opto-electro-mechanical systems (MOEMS) has prominent advantages over conventional optical devices, such as smaller, lighter, more stable, lower cost and power consumption. It has been widely applied in the last few years. This paper presents a micro spectrometer based on torsional MEMS grating with micromachining process. As a diffractive component in the micro spectrometer, the torsional MEMS grating is actuated by

Bin Yan; Weizheng Yuan; Ruikang Sun; Dayong Qiao; Yiting Yu; Taiping Li

2010-01-01

145

A variable-dispersion micro-spectrometer  

Microsoft Academic Search

A space-variant variable-dispersion micro-spectrometer has been designed, fabricated, and tested. This spectrometer allows the dispersion to be varied on a pixel-by-pixel basis across the one-dimensional entrance slit. Micro-electro-mechanical mirrors are located at the entrance slit and direct light to one of three different diffraction gratings. A standard grating spectrometer geometry is used to achieve diffraction-limited performance across the 500--1000 nm

Eric Arden Shields

2003-01-01

146

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

NASA Astrophysics Data System (ADS)

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.

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

147

Image quality with array spectrometers  

Microsoft Academic Search

We present data on the image quality achieved with the near IR array spectrometer cooled grating spectrometer 4 (CGS4) on the UK IR telescope (UKIRT) on Mauna Kea. A design spot size of 30 micrometers was specified for CGS4, to maintain acceptable image quality with both the 58 by 62 pixel array with which it is currently equipped and the

Suzanne K. Ramsay Howat; Gillian S. Wright; David Montgomery; Eli I. Atad-Ettedgui

1994-01-01

148

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

PubMed

We have constructed a high-resolution grazing-incidence spectrometer designed for measuring the ion temperature of low-Z elements, such as Li(+) or Li(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(+) and 65 eV for the 135 Å Li(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. PMID:25430206

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

2014-11-01

149

High-resolution grazing-incidence grating spectrometer for temperature measurements of low-Z ions emitting in the 100-300 Å spectral banda)  

NASA Astrophysics Data System (ADS)

We have constructed a high-resolution grazing-incidence spectrometer designed for measuring the ion temperature of low-Z elements, such as Li+ or Li2 +, 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+ and 65 eV for the 135 Å Li2 + 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.

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

2014-11-01

150

Nanostructure Diffraction Gratings for Integrated Spectroscopy and Sensing  

NASA Technical Reports Server (NTRS)

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.

Guo, Junpeng (Inventor)

2015-01-01

151

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

NASA Astrophysics Data System (ADS)

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 ?-doped CCD. The microchannel plate will deliver 30 ?m 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.

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

2012-09-01

152

Fiber grating sensors  

Microsoft Academic Search

We review the recent developments in the area of optical fiber grating sensors, including quasi-distributed strain sensing using Bragg gratings, systems based on chirped gratings, intragrating sensing concepts, long period-based grating sensors, fiber grating laser-based systems, and interferometric sensor systems based on grating reflectors

Alan D. Kersey; Michael A. Davis; Heather J. Patrick; Michel LeBlanc; K. P. Koo; C. G. Askins; M. A. Putnam; E. Joseph Friebele

1997-01-01

153

The Polychromator: A programmable MEMS diffraction grating for synthetic spectra  

SciTech Connect

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.

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

154

Development of Off-Plane Reflection Grating Alignment Fixtures  

NASA Astrophysics Data System (ADS)

Currently, grating spectrometers are used onboard the Chandra X-ray Observatory and XMM-Newton in orbit around the Earth. However, future goals of greater spectral resolving power and greater effective areas necessitate a new generation of high-quality spectrometers. Off-plane reflection gratings can be used to provide high throughput and spectral resolution in the 0.3-2.0 keV band, allowing for unprecedented diagnostics of energetic astrophysical processes. A grating spectrometer consists of multiple aligned gratings intersecting the converging beam of a Wolter-I telescope. Each grating will be aligned such that the diffracted spectra overlap at the focal plane. Misalignments will degrade both spectral resolution and effective area. With analytical alignment tolerances calculated, laboratory techniques to achieve these tolerances for flight-like optics must be developed. We present the results from our first and second generation alignment fixtures, as well as wavefront stitching methods.

Donovan, Benjamin D; Allured, Ryan; McEntaffer, Randall L.

2014-06-01

155

High-end spectroscopic diffraction gratings: design and manufacturing  

NASA Astrophysics Data System (ADS)

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.

Glaser, Tilman

2015-02-01

156

Microspectrometer based on flat field holographic concave grating  

Microsoft Academic Search

A micro-spectrometer which adopts the holographic concave grating as imaging and dispersing element is introduced in the paper. Using ZEMAX soft ware tools, the optimal design of aberration correction of the concave grating which retains the image quality without sacrificing the resolution is coming up with. The portable micro-spectrometer with F\\/#4 is developed. During 350nm to 800nm wavelength range, the

Chaoming Li; Xinrong Chen; Jianhong Wu; Zhuyuan Hu

2010-01-01

157

Super-smooth x-ray reflection grating fabrication  

Microsoft Academic Search

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

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

1997-01-01

158

Athermalized low-loss echelle-grating-based multimode dense wavelength division demultiplexer  

E-print Network

demultiplexer DEMUX capable of demultiplexing eight-channel 200-GHz optically spaced signals into a 62.5- m insertion loss of this DEMUX is 1.95 dB. Thermal analysis and temperature testing results are reported DEMUXs quite attractive for multimode DWDM applica- tions.9,10 Meanwhile, there is also an urgent need

Chen, Ray

159

Material identification employing a grating spectrometer  

DOEpatents

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.

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

2007-01-09

160

Design of a portable microfiber optic spectrometer  

Microsoft Academic Search

Spectrum examination is widely used in scientific research and production. With the development of scientific research and production, the trend of spectrum examination is from indoor to outdoor in situ examination and on-line monitor. So the spectrometer is required to be more minimal. A new type of portable micro fiber spectrometer, using CCD, blaze grating, and two spherical mirror, a

Jian-Ping Tong; Yang Yang; Cheng-Hua Sui; Dang-Yang Xu; Fei Wang

2010-01-01

161

Imaging spectrometer wide field catadioptric design  

DOEpatents

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.

Chrisp; Michael P. (Danville, CA)

2008-08-19

162

The Constellation-X RGS options: Raytrace Modeling of the Off-plane Gratings  

E-print Network

The Constellation-X RGS options: Raytrace Modeling of the Off-plane Gratings K.A. Flanagan, J The Reflection Grating Spectrometer of the Constellation-X mission has two strong candidate configurations-ray, spectrometer, high resolution, CCD 1. INTRODUCTION Constellation-X is a high-throughput high

163

Multiple order common path spectrometer  

NASA Technical Reports Server (NTRS)

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.

Newbury, Amy B. (Inventor)

2010-01-01

164

Mathematical Simulation for Integrated Linear Fresnel Spectrometer Chip  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

165

Analysis of the focal pattern distortion of a cylindrical concave micro-grating in a slab waveguide and the mechanism of spatial resolution recovery  

Microsoft Academic Search

With modern lithographic technology, a compact spectrometer is designed to include a blazed micro-grating with cylindrical concave grating profile. In order to restrict the sagittal beam divergence and to reduce the size of the spectrometer, the micro-grating is embedded inside a pair of planar mirrors used as a slab waveguide. In the simulations for the effect of the waveguide, we

Cheng-Hao Ko; Jian-Shian Lin; Nien-Po Chen; Chang-Tai Chen; Ji-Lin Shen

2010-01-01

166

Holographic optical grating and method for optimizing monochromator configuration  

DOEpatents

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.

Koike, Masato (Moraga, CA)

1999-01-01

167

Investigation and Progress of MicroSpectrometer's Light Splitting System  

Microsoft Academic Search

It becomes possible to micro spectrometers with the development of micromachining techniques such as MEMS (micro electro mechanical systems). According to different dispersive elements used by micro spectrometers, the paper mainly illuminates the principle and fabrication technology of typical micro spectrometers whose dispersive elements adopt silicon micro grating, filter and Febry-Perot resonant cavity. The paper briefly summarizes the advantages, disadvantages

Wang Yongqing; Li Chunli; Sun Rongxia; Wang Haizhou

2007-01-01

168

Advances in reflection grating technology for Constellation-X Ralf K. Heilmann, Mireille Akilian, Chih-Hao Chang, Carl G. Chen, Craig R. Forest, Chulmin  

E-print Network

Advances in reflection grating technology for Constellation-X Ralf K. Heilmann, Mireille Akilian The Reflection Grating Spectrometer (RGS) on Constellation-X will require thousands of large gratings with very submicron assembly repeatability. Keywords: x-ray optics, Constellation-X, in-plane gratings, off

169

High Resolution Coude Echelle Spectroscopy of IX Per  

NASA Astrophysics Data System (ADS)

High resolution (R = 45000) Coude-Echelle spectra of IX Per has been obtained at TÜB?TAK National Observatory (TUG) of Turkey. IX Per has been known to be a single lined (SB1) spectroscopic binary having chromospheric activity. However, analyzed spectra of IX Per by KOREL disentangling method indicated that the system is a double lined (SB2) spectroscopic binary. Weaker lines from the secondary are discovered on the decomposed spectra. A preliminary orbit indicates that the mass ratio of the system is 0.64. The light contribution of the secondary is up to 10% in investigated spectral region. Circular orbit is sufficient to explain radial velocity variations.

Ak, N. Filiz; Eker, Z.; Ak, H.; Küçük, I.

2009-02-01

170

Critical-Angle Transmission Grating Development for AXSIO  

NASA Astrophysics Data System (ADS)

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. 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). Since the demise of IXO there are no soft x-ray spectroscopy missions in the pipeline, but several new mission concepts containing CAT grating based spectrometers such as AXSIO promise to deliver unprecedented order-of-magnitude improvements in soft x-ray spectroscopy figures of merit. The CAT grating principle has previously been demonstrated with x rays using small wet-etched samples. We report the latest progress in the fabrication and testing of large (32x32 mm^2) CAT grating prototypes with an integrated hierarchy of low-obstruction support structures. The gratings are fabricated from silicon-on-insulator wafers using advanced lithography and highly anisotropic dry and wet etching techniques. We present our latest grating fabrication results.

Heilmann, Ralf K.; Bruccoleri, A.; Mukherjee, P.; Schattenburg, M. L.; Bautz, M. W.; Huenemoerder, D.; Davis, J. E.; Dewey, D.; Marshall, H. L.; Schulz, N. S.

2013-01-01

171

Critical-angle Transmission Grating Development for AXSIO  

NASA Astrophysics Data System (ADS)

Large area, high resolving power spectroscopy in the soft x-ray band can at present only be achieved with a state-of-the-art diffraction grating spectrometer. 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 such as AXSIO promise to deliver unprecedented order-of-magnitude improvements in soft x-ray spectroscopy figures of merit. The CAT grating principle has previously been demonstrated with x rays using small wet-etched samples. We report the latest progress in the fabrication and testing of large (32x32 mm2) CAT grating prototypes with an integrated hierarchy of low-obstruction support structures. The gratings are fabricated from silicon-on-insulator wafers using advanced lithography and highly anisotropic dry and wet etching techniques. We present our latest grating fabrication results.

Bautz, Mark W.; Heilmann, R. K.; Schattenburg, M.; Marshall, H. L.; Huenemoerder, D.; Dewey, D.; Schulz, N. S.; Davis, J. E.

2013-04-01

172

Research directed toward improved echelles for the ultraviolet  

NASA Technical Reports Server (NTRS)

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.

1977-01-01

173

PEPSI: the Potsdam Echelle Polarimetric and Spectroscopic Instrument for the LBT  

NASA Astrophysics Data System (ADS)

We present the status of PEPSI, the bench-mounted fibre-fed and stabilized "Potsdam Echelle Polarimetric and Spectroscopic Instrument" for the 2×8.4m Large Binocular Telescope in southern Arizona. PEPSI is under construction at AIP and is scheduled for first light in 2009/10. Its ultra-high-resolution mode will deliver an unprecedented spectral resolution of approximately R=310,000 at high efficiency throughout the entire optical/red wavelength range 390-1050nm without the need for adaptive optics. Besides its polarimetric Stokes IQUV mode, the capability to cover the entire optical range in three exposures at resolutions of 40,000, 130,000 and 310,000 will surpass all existing facilities in terms of light-gathering-power times spectral-coverage product. A solar feed will make use of the spectrograph also during day time. As such, we hope that PEPSI will be the most powerful spectrometer of its kind for the years to come.

Strassmeier, K. G.; Woche, M.; Ilyin, I.; Popow, E.; Bauer, S.-M.; Dionies, F.; Fechner, T.; Weber, M.; Hofmann, A.; Storm, J.; Materne, R.; Bittner, W.; Bartus, J.; Granzer, T.; Denker, C.; Carroll, T.; Kopf, M.; DiVarano, I.; Beckert, E.; Lesser, M.

2008-07-01

174

GOSPEC - The infrared spectrometer of TIRGO  

NASA Astrophysics Data System (ADS)

This paper describes the structure of the GOSPEC, a new instrument for the TIRGO observatory. It is a cryogenically cooled grating spectrometer equipped with a seven-element InSb array detector, which can be used both as a spectrometer with a resolution of 300-2600 between 1 and 5 microns and as a mapping photometer in the IR bands J-H-K-L-M. The optical system's grating is in Littrow configuration, with 300 grooves/mm and the blaze angle of 36 deg 52 min. The back of the grating is a plane mirror, so that when the grating is rotated 180 deg, the instrument works as a photometer with mapping capability in the band defined by the filters. The results of tests showed a good optical quality of the image (the image size at 80 percent of energy was about 0.04 mm) and a good mechanical stability of the optical system.

Gennari, S.

175

Multilayer diffraction grating  

DOEpatents

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. 2 figs.

Barbee, T.W. Jr.

1990-04-10

176

Water-cooled grate  

SciTech Connect

A description is given of a furnace for the combustion of solid fuel comprising: a first, inclined grate portion having an upper end and a lower end, the upper end adjacent to a side wall defining the furnace, said first grate portion extending outwardly below a combustion space; means for supplying fuel to the upper end of said inclined, first grate portion; an angular, second grate portion spaced apart from the lower end of said first grate portion and comprising a first, mainly upwardly part facing said first grate portion, and a second, mainly horizontal part extending backwards, below said first grate portion to receive fuel residues therefrom; means for suppyling combustion air to said first and said second grate portions; and a passageway for conducting combustion gases from said second part of said second portion to the upper end of said first grate portion.

Lis, P.; Olausson, K.

1980-07-22

177

Multilayer diffraction grating  

DOEpatents

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.

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

1990-01-01

178

Design Study of an Adaptive Optics Visual Echelle Spectrograph and Imager for the VLT  

E-print Network

Design Study of an Adaptive Optics Visual Echelle Spectrograph and Imager for the VLT R study for an adaptive optics visual echelle spectrograph and imager/coronograph for use as parallel instrument of the Nasmyth Adaptive Optics System (NAOS) on unit UT3 (Melipal) of the VLT. The spectrograph

179

Materials and Fabrication Issues for Large Machined Germanium Immersion Gratings  

SciTech Connect

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.

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

2006-05-22

180

Multilayer coated gratings for phase-contrast computed tomography (CT)  

NASA Astrophysics Data System (ADS)

By using the principle of grating interferometry, X-ray phase contrast imaging can now be performed with incoherent radiation from standard X-ray tube. This approach is in stark contrast with imaging methods using coherent synchrotron X-ray sources or micro-focus sources to improve contrast. The gratings interferometer imaging technique is capable of measuring the phase shift of hard X-rays travelling through a sample, which greatly enhances the contrast of low absorbing specimen compared to conventional amplitude contrast images. The key components in this approach are the gratings which consists of alternating layers of high and low Z (atomic number) materials fabricated with high aspect ratios. Here we report on a novel method of fabricating the grating structures using the technique of electron-beam (ebeam) thin film deposition. Alternating layers of silicon (Z=14) and tungsten (Z=74) were deposited, each measuring 100 nm each, on a specially designed echelle substrate, which resulted in an aspect ratio of ~100:1. Fabrication parameters related to the thin film deposition such as geometry, directionality, film adhesion, stress and the resulting scanning electron micrographs will be discussed in detail. Using e-beam method large-area gratings with precise multilayer coating thicknesses can be fabricated economically circumventing the expensive lithography steps.

Marton, Zsolt; Bhandari, Harish B.; Wen, Harold H.; Nagarkar, Vivek V.

2014-03-01

181

Progress of performance of MOEMS micro spectrometers through enhanced signal processing, detectors and system setup  

Microsoft Academic Search

Micro spectrometers have been realized by the use of MEMS based scanning grating chips several years ago. The main advantage is the requirement of a single detector instead of a detector array for micro spectrometers applying fixed gratings. Especially in the near infrared range beyond the detection limit of silicon detectors, this can help to reduce the system costs significantly.

Heinrich Grüger; Thomas Egloff; Matthias Messerschmidt; Michael Scholles

2008-01-01

182

Varied line-space gratings: past, present and future  

SciTech Connect

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.

Hettrick, M.C.

1985-08-01

183

Monolithic spectrometer  

DOEpatents

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.

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

184

Monolithic spectrometer  

DOEpatents

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.

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

185

Multi-Cantilever-Driven Rotational Micrograting for MOEMS Spectrometer  

Microsoft Academic Search

For the purpose of detecting biological fluorescence, a rotational actuator with integrated diffraction grating is designed as the central part of a MOEMS spectrometer. In order to produce scanning with a lithographically defined micrograting, angular displacement is produced with multiple balanced beams placed in opposition around a semi-floating pivot point. Piezoelectrically driven, the beams rotate a suspended micro grating linearly

J. F. Lo; Shih-Jui Chen; Hongyu Yu; D. Chi; Chuang-Yuan Lee; L. Marcu; Eun Sok Kim; M. Gundersen

2007-01-01

186

Michelle: a mid-infrared spectrometer for UKIRT and Gemini  

Microsoft Academic Search

Michelle is a long slit grating spectrometer which is being built at the Royal Observatory Edinburgh for the UKIRT and Gemini telescopes. It will incorporate five diffraction gratings and seven entrance slits to give spectral resolving powers ranging from a few dozen up to 3,000, with wavelength coverage from 5 to 28 mum. In addition, the same detector array can

A. C. H. Glasse; E. E. Atad-Ettedgui; I. R. Bryson; G. F. Morrison

1995-01-01

187

The Echelon-cross-Echelle Spectrograph for SOFIA  

NASA Astrophysics Data System (ADS)

The Echelon-cross-Echelle Spectrograph (EXES), one of the first generation instruments for the Statospheric Observatory for Infrared Astronomy (SOFIA) will provide a unique tool for examining the ISM and star formation. The EXES high spectral resolution mode, R ? 120 000 from 4.5 ?m to 28.3 ?m, is designed for line observations of gas-phase molecules. The improved atmospheric transmission guaranteed by SOFIA will make observations of molecules such as H2O and CH4 fairly routine. EXES will also have medium and low resolution modes to enable a wide range of science projects. EXES is a PI instrument open for collaborative proposals following the model of the successful TEXES instrument (Lacy et al. 2002). It is currently scheduled for first science flights on SOFIA in 2013.

Richter, M. J.; Seifahrt, A.; McKelvey, M.; Zell, P.

2011-11-01

188

Development of Multiple-Element Flame Emission Spectrometer Using CCD Detection  

ERIC Educational Resources Information Center

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,…

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

2005-01-01

189

The Off-plane Grating Rocket Experiment (OGRE)  

NASA Astrophysics Data System (ADS)

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.

McEntaffer, Randall L.; DeRoo, Casey; Tutt, James; Schultz, Ted; Zhang, William; McClelland, Ryan; Murray, Neil; Holland, Andrew

2014-08-01

190

Renewable liquid reflection grating  

DOEpatents

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.

Ryutov, Dmitri D.; Toor, Arthur

2003-10-07

191

Catwalk grate lifting tool  

DOEpatents

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.

Gunter, Larry W. (615 Sandpit Rd., Leesville, SC 29070)

1992-01-01

192

Catwalk grate lifting tool  

DOEpatents

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.

Gunter, L.W.

1992-08-11

193

Transmission Grating Measurements of Undulator K  

SciTech Connect

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.

Bionta, R. M.

2010-12-01

194

Multilayer dielectric diffraction gratings  

DOEpatents

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.

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

195

Multilayer dielectric diffraction gratings  

DOEpatents

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.

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

1999-05-25

196

Toroidal Varied-Line Space (TVLS) Gratings  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

197

Correlation spectrometer  

DOEpatents

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.

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

198

Multidimensional spectrometer  

DOEpatents

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.

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

2010-07-20

199

CD Spectrometer  

NSDL National Science Digital Library

In this activity, learners use a compact disc to make a spectrometer, an instrument used to measure properties of light. Learners use their spectrometer to view a continuous spectrum produced by fluorescent light. This lesson guide also includes instructions on how to build a spectroscope from a cereal box.

Paul Doherty

2000-01-01

200

High Resolution VUV Spectrometer at the INDUS-1 Synchrotron Source  

SciTech Connect

An indigenously developed high-resolution vacuum ultraviolet (VUV) spectrometer has recently been commissioned at the INDUS-1 Synchrotron Source, Indore, India for carrying out spectroscopic research of atomic and molecular gases. The spectrometer uses a 6.65-meter concave grating in off-plane Eagle mounting and a photomultiplier tube (PMT) for recording the intensity profile of various spectral lines. Experimental performance of the spectrometer has been tested using laboratory sources and 1200 grooves/mm and 4800 grooves/mm concave gratings. Wavelength resolutions of 0.08 Aa and 0.01 Aa have been achieved when 1200 grooves/mm and 4800 grooves/mm concave gratings have been mounted successfully in the spectrometer. The instrument has been integrated with the high resolution VUV beamline at INDUS-1 and its performance is being evaluated with synchrotron radiation.

Das, Nimai C.; Shukla, Ram P.; Udupa, Dinesh V.; Sahoo, Naba K.; Bhattacharyya, Dibyendu; Sunanda, K.; Saraswathy, P. [Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai -400 085 (India)

2007-01-19

201

Holographic spectrometer for astronomy: design and experiments--initial laboratory results  

NASA Astrophysics Data System (ADS)

In order to fulfill the need of high astronomical observation spectral resolution, we are developing a new stationary interferometric spectrometer: heterodyne holographic spectrometer (HHS). It utilizes the configuration of a Twyman- Green interferometer with two arms adjusted for zero path difference and with a plane diffraction grating replacing one of the arm mirrors. So, it combines the multi-advantages of traditional spectrometers: SGS and FTS (slit grating spectrometer and Fourier transform spectrometer), and avoids their disadvantages, especially in the observation with telescope. We get its experimental result in the laboratory and have a simple discussion on its application prospect in astronomy.

Zhou, Bifang; Wang, Haitao; Zhao, Peiqian

1997-05-01

202

Reflective diffraction grating  

DOEpatents

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.

Lamartine, Bruce C. (Los Alamos, NM)

2003-06-24

203

Deformed ellipsoidal diffraction grating blank  

NASA Technical Reports Server (NTRS)

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.

Decew, Alan E., Jr.

1994-01-01

204

Galileo Ultraviolet Spectrometer experiment  

NASA Technical Reports Server (NTRS)

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.

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

205

MEMS infrared gas spectrometer based on a porous silicon tunable filter  

Microsoft Academic Search

We present a MEMS infrared spectrometer for selective and quantitative chemical gas analysis. Infrared absorption spectroscopy can distinguish gases easily and also detect nonreactive molecules like CO 2, in contrast to e.g. metal oxide gas sensors. The following new spectrometer concept avoids expensive linear detectors as used for grating spectrometers: A tunable interference filter scans the desired part of the

Gerhard Lammel; Sandra Schweizer; Philippe Renaud

2001-01-01

206

All-optical fabrication of blazed grating on Pcyclic-azoMMA film  

NASA Astrophysics Data System (ADS)

Blazed grating is a key diffractive optical element in spectrometer. Different from the traditional holographic ion beam etching method, blazed grating has been fabricated on a novel polymer with cyclic-azobenzene pendants (Pcyclic-azoMMA) by all optical fabrication with two steps in this paper. Firstly, use two interfering Kr+ laser beams with the most efficient RCP+LCP polarization to inscribe symmetric surface relief gratings on polymer film. After that, make a single laser beam with polarization perpendicular to the grating grooves irradiate slantly to induce blazed asymmetric structure. The distribution of the near field of the grating while single linearly polarized beam irradiate slantly at different angles was simulated. The calculation demonstrates that -1st order diffraction efficiency of blazed gratings is similar to that of triangle blazed grating.

Xu, Lixiong; Wu, Jianhong; Wang, Jian; Chen, Xinrong

2014-11-01

207

Echelle Studies of the DB Degenerate GD358  

NASA Astrophysics Data System (ADS)

Our Tenth Episode high resolution SWP image of the first DB white dwarf (GD358) ever to be observed with the IUE echelle unexpectedly revealed the apparent presence of an Einstein-redshifted C II absorption line at the 200 mA level. If real, this detection is the first of carbon in a hot DB star and should lead to a major breakthrough in our understanding of DB evolution by providing a critical test of the role of convective dredge-up versus interstellar cloud accretion (or radiative levitation) in explaining the presence of carbon in hot DB stars and therefore in their cooler helium-rich, presumed descendants, the class of carbon band DQ degenerates. The resulting carbon abundance would be a direct test of the theoretical prediction of convective dredge-up of core carbon from its equilibrium diffusion tail by Fontaine et al (1984) and by Pelletier et al (1986). It would also provide a clear cut test of convective efficiency/mixing length theory in DB envelopes. Our scientific objective here is two-fold: (1) We must have a confirmatory second SWP image of this hottest (and pulsating prototype) DB in order to confirm this critically important feature and several other somewhat weaker possible photospheric candidates in SWP31432; (2) In order to search further for the presence of trace metals as a test of accretion versus dredge-up and to derive stringent upper limit metal abundances (or abundances from the mix of detected ions) we propose to obtain the first and only LWP high resolution image of a DB. In selecting GD358, we will therefore have complete high resolution IUE coverage of this object in our search for trace metals undetectable at low IUE resolution.

Sion, Edward M.

208

CAFE: Calar Alto Fiber-fed Echelle spectrograph  

NASA Astrophysics Data System (ADS)

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.

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

2011-11-01

209

Cascaded interferometric imaging spectrometer  

NASA Astrophysics Data System (ADS)

We present what we believe to be a novel method for order sorting a Fabry-Perot interferometer using a Fourier transform spectrometer (FTS) in tandem. We demonstrate how the order sorting is achieved using a model instrument response as an example of an instrument working in the 5-25 ?m band, although the method is generally applicable at all wavelengths. We show that an instrument of this type can be realized with a large bandwidth, a large field of view, and good transmission efficiency. These attributes make this instrument concept a useful technique in applications where true imaging spectroscopy is required, such as mapping large astronomical sources. We compare the performance of the new instrument to grating and standard FTS instruments in circumstances where the measurement is background and detector noise limited. We use a figure of merit based on the field of view and speed of detection and find that the new system has a speed advantage over a FTS with the same field of view in all circumstances. The instrument will be faster than a grating instrument with the same spectral resolution once the field of view is >13 times larger under high background conditions and >50 times larger with detector performances that match the photon noise from Zodiacal light.

Swinyard, Bruce; Ferlet, Marc

2007-09-01

210

The diffraction grating in the Ivory optomechanical modeling tools  

NASA Astrophysics Data System (ADS)

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.

Hatheway, Alson E.

2013-09-01

211

Water-cooled grate  

Microsoft Academic Search

A description is given of a furnace for the combustion of solid fuel comprising: a first, inclined grate portion having an upper end and a lower end, the upper end adjacent to a side wall defining the furnace, said first grate portion extending outwardly below a combustion space; means for supplying fuel to the upper end of said inclined, first

P. Lis; K. Olausson

1980-01-01

212

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

NASA Astrophysics Data System (ADS)

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.

Hu, Shao Ming; Gao, Dong Yang

2014-11-01

213

Dual waveband compact catadioptric imaging spectrometer  

DOEpatents

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.

Chrisp, Michael P.

2012-12-25

214

HyTES: Thermal Imaging Spectrometer Development  

NASA Technical Reports Server (NTRS)

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.

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

215

New family of reflective spectrometers  

NASA Astrophysics Data System (ADS)

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.

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

2011-01-01

216

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

NASA Technical Reports Server (NTRS)

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.

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

217

Spectrometer gun  

DOEpatents

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.

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

1985-01-01

218

Spectrometer gun  

DOEpatents

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.

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

1981-11-03

219

Color separation gratings  

NASA Technical Reports Server (NTRS)

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.

Farn, Michael W.; Knowlden, Robert E.

1993-01-01

220

Wire Diffraction Gratings  

NASA Astrophysics Data System (ADS)

In the summer of 1972, I attended the workshop on recreating classic experiments in physics at Barnard College. This was developed by Samuel Devons, and it was a defining experience that set me toward a research career involving early physics teaching apparatus. During the course of the workshop, I became curious about the original diffraction gratings developed by Fraunhofer and built a wire diffraction. A short note about the gratings was published in the American Journal of Physics the next year.2

Greenslade, Thomas B.

2004-02-01

221

Alignment of the grating wheel mechanism for a ground-based cryogenic near-infrared astronomy instrument  

Microsoft Academic Search

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), principle investigator-class instrument for the 2.1 m and Mayall 3.8 m telescopes at Kitt Peak National Observatory, and a MEMS spectrometer concept demonstrator for the James Webb Space Telescope. The

Sharon M. Gutkowski; Raymond G. Ohl; Jason E. Hylan; John G. Hagopian; Stephen E. Kraft; J. E. Mentzell; Joseph A. Connelly; Joseph P. Schepis; Leroy M. Sparr; Matthew A. Greenhouse; John W. MacKenty

2003-01-01

222

Grate for coal stove  

SciTech Connect

A stove grate for guiding fuel in two flows is described. The grate includes a stationary floor extending between opposed ends of the grate; spaced sidewalls extending along the sides of the floor between the ends of the grate. The floor includes an entrance section at one end of the gate, a fire support section at the other end of the grate above the entrance section and rise section means extending upwardly between the entrance section and the fire support section for guiding a lower fuel flow upwardly along the floor to the fire support section. It also guides an upper fuel flow located above the first flow up to fill a fuel reservoir located above the floor at the entrance section and at the lower part of the rise section means without overflowing the sidewalls. A plurality of combustion air openings in the floor of the grate extend along the upper part of the rise section means and along the fire support section, the entrance section and the lower part of the rise section being free of combustion air openings.

Harman, D.P.

1989-02-14

223

Signal processing for a single detector MOEMS based NIR micro spectrometer  

Microsoft Academic Search

The examination of spectra in the NIR range is necessary for applications like process control, element analysis or medical systems. Typically integrated NIR spectrometers are based on optical setups with diffraction grating and detector arrays. The main disadvantage is price and availability of NIR array InGaAs-based detectors. The implementation of a scanning grating chip realized in a MOEMS technology which

Andreas Heberer; Heinrich Grüger; Fabian Zimmer; Harald Schenk; Andreas Kenda; Albert Frank; Werner Scherf

2005-01-01

224

Imaging IR spectrometer, phase 2  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

225

Miniaturized MOEMS spectrometer for NIR applications  

NASA Astrophysics Data System (ADS)

Optical spectroscopy is a common tool for many applications. Micro systems most often use fixed gratings and array detectors. In the infrared wavelength range above the limit for Si-detectors (1100nm) and Ge-detectors (1700nm) respectively, this is either very expensive or almost impossible. Micro opto electro mechanical systems (MOEMS) offer very promising options. A movable grating can be realized by a silicon chip, using the technology of a well established scanner mirror chips in combination with the realization of a reflective grating either through etching of the aluminium mirror layer or even a more sophisticated technology. The patented resonant drive realizes a mechanical angle of +/-7° with CMOS compatible voltages of approximately 20V. This technology leads to the realization of a set up close to a classical Czerny-Turner spectrometer using a single detector only. The device offers the capability to be scaled down to the size of a cigarette box. The spectrometer presented here was adjusted to 900...2500nm range. The scanning grating chip has either 500, 625 or 714 lines/mm. As detector serves a fast InGaAs photodiode, read out through a 12 Bit AD converter. The sinusoidal movement is unfolded by a signal processor (TI TMS320F2812) which also computes the spectrum. Acquired data can be shown by a display or transmitted to a host PC. System tests have been performed using infrared LEDs. Wavelengths have been 1300, 1400 or 1550nm for example. The spectrometer is working accurately. First result of micro shaped grating structures to enhance the sensitivity are presented.

Grueger, Heinrich; Heberer, Andreas; Zimmer, Fabian; Wolter, Alexander; Schenk, Harald

2005-08-01

226

Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra  

NASA Astrophysics Data System (ADS)

We present a technique to extract radial velocity (RV) measurements from echelle spectrograph observations of rapidly rotating stars (V sin i? 50 km s?1). This type of measurement is difficult because the line widths of such stars are often comparable to the width of a single echelle order. To compensate for the scarcity of lines and Doppler information content, we have developed a process that forward-models the observations, fitting the RV shift of the star for all echelle orders simultaneously with the echelle blaze function. We use our technique to extract RV measurements from a sample of rapidly rotating A- and B-type stars used as calibrator stars observed by the California Planet Survey observations. We measure absolute RVs with a precision ranging from 0.5–2.0 km s?1 per epoch for more than 100 A- and B-type stars. In our sample of 10 well-sampled stars with RV scatter in excess of their measurement uncertainties, three of these are single-lined binaries with long observational baselines. From this subsample, we present detections of two previously unknown spectroscopic binaries and one known astrometric system. Our technique will be useful in measuring or placing upper limits on the masses of sub-stellar companions discovered by wide-field transit surveys, and conducting future spectroscopic binarity surveys and Galactic space-motion studies of massive and/or young, rapidly rotating stars.

Becker, Juliette C.; Johnson, John Asher; Vanderburg, Andrew; Morton, Timothy D.

2015-04-01

227

ORIENTATION RELATIONNELLE VERSUS TRANSACTIONNELLE DU CLIENT : DEVELOPPEMENT D'UNE ECHELLE DANS LE  

E-print Network

1 ORIENTATION RELATIONNELLE VERSUS TRANSACTIONNELLE DU CLIENT : DEVELOPPEMENT D'UNE ECHELLE DANS LE SECTEUR BANCAIRE FRANÇAIS. UNE ETUDE EXPLORATOIRE Benamour Y. & Prim I. (2000), Orientation relationnelle étude exploratoire dans le but de développer une échelle de mesure de l'orientation transactionnelle

Paris-Sud XI, Université de

228

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

NASA Technical Reports Server (NTRS)

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.

Morrison, Nancy D.; Zimba, Jason R.

1990-01-01

229

Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra  

E-print Network

We present a technique to extract radial velocity measurements from echelle spectrograph observations of rapidly rotating stars ($V\\sin{i} \\gtrsim 50$ km s$^{-1}$). This type of measurement is difficult because the line widths of such stars are often comparable to the width of a single echelle order. To compensate for the scarcity of lines and Doppler information content, we have developed a process that forward-models the observations, fitting the radial velocity shift of the star for all echelle orders simultaneously with the echelle blaze function. We use our technique to extract radial velocity measurements from a sample of rapidly rotating A- and B-type stars used as calibrator stars observed by the California Planet Survey observations. We measure absolute radial velocities with a precision ranging from 0.5-2.0 km s$^{-1}$ per epoch for more than 100 A- and B-type stars. In our sample of 10 well-sampled stars with radial velocity scatter in excess of their measurement uncertainties, three of these are s...

Becker, Juliette C; Vanderburg, Andrew; Morton, Timothy D

2015-01-01

230

Guider camera and software for 1.5m echelle A. Tokovinin  

E-print Network

on the entrance hole (analogue of a spectrograph slit) is done with an analogue TV camera WAT902HS by observing written by R.Cantarutti in C is driven by a GUI, it sends the correction commands to the TCS computer (Vx on the echelle has to fulfill the following requirements: · Digital CCD camera of VGA resolution (640x480 pixels

Tokovinin, Andrei A.

231

Scanning imaging absorption spectrometer for atmospheric chartography  

NASA Technical Reports Server (NTRS)

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.

Burrows, John P.; Chance, Kelly V.

1991-01-01

232

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

NASA Technical Reports Server (NTRS)

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.

Schattenburg, Mark L.

2005-01-01

233

Calibration of a High Resolution Soft X-ray Spectrometer  

SciTech Connect

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).

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

2010-01-26

234

Imaging micro-spectrometer with adaptive space-variant dispersion  

Microsoft Academic Search

A space-variant variable-dispersion imaging micro-spectrometer is described. An array of MEMs mirrors is used to select different optical paths through the spectrometer, permitting dynamically adjustable grating dispersion on a pixel-by-pixel basis across the image. Diffraction-limited performance is achieved across the 500-1000 nm wavelength range; and spectral resolutions ranging from 5 to 20 nm

W. Zhou; E. Shield; W. Liu; J. Leger; J. Talghader

2005-01-01

235

Fiber laser FBG sensor system by using a spectrometer demodulation  

NASA Astrophysics Data System (ADS)

We suggest a spectrometer demodulation method of FBG sensors for the possible uses in wind power generator's blade monitoring. High signal-to-noise ratio outputs and linear demodulation were obtained by combining a fiber laser light source and a spectrometer which used a holographic volume grating and a 512-pixel PD array. Preliminary experimental results are presented to show the feasibility of the suggested FBG demodulation system.

Kim, Hyunjin; Song, Minho

2011-05-01

236

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

237

Charged particle accelerator grating  

DOEpatents

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.

Palmer, Robert B. (Shoreham, NY)

1986-01-01

238

Nanofabrication advances for high efficiency critical-angle transmission gratings  

NASA Astrophysics Data System (ADS)

We report several break-through nanofabrication developments enabling high efficiency and high resolving power spectrometers in the soft x-ray band. The device is the critical-angle transmission (CAT) grating, which combines the low mass and relaxed alignment tolerances of a transmission grating with the high broad-band efficiency and high diffraction orders of a blazed reflection grating. Past work successfully demonstrated the CAT grating concept; however, the open-area fraction was often less than 20% whilst more than 50% is desired. This presents numerous nanofabrication challenges including a requirement for a freestanding silicon membrane of ultra high-aspect ratio bars at a period of 200 nanometers with minimal cross support blockage. Furthermore, the sidewalls must be smooth to a few nanometers to efficiently reflect soft x-rays. We have developed a complete nanofabrication process for creating freestanding CAT gratings via plasma-etching silicon wafers with a buried layer of SiO2. This removable buried layer enables combining a record-performance plasma etch for the CAT grating with a millimeter-scale honeycomb structural support to create a large-area freestanding membrane. We have also developed a process for polishing sidewalls of plasma-etched ultra-high aspect ratio nanoscale silicon structures via potassium hydroxide (KOH). This process utilizes the anisotropic etch nature of single crystal silicon in KOH. We developed a novel alignment technique to align the CAT grating bars to the {111} planes of silicon within 0.2 degrees, which enables KOH to etch away sidewall roughness without destroying the structure, since the {111} planes etch approximately 100 times slower than the non-{111} planes. Preliminary results of a combined freestanding grating with polishing are presented to enable efficient diffraction of soft x-rays.

Bruccoleri, Alexander R.; Guan, Dong; Heilmann, Ralf K.; Vargo, Steve; DiPiazza, Frank; Schattenburg, Mark L.

2013-09-01

239

High Velocity Outflows in AGNs Observed with Gratings  

NASA Astrophysics Data System (ADS)

Several Active Galactic Nuclei (AGNs) have been reported to harbor fast outflows exceeding 10,000 km s-1, which are detected mostly in their low-resolution CCD X-ray spectra. Only few, however, were detected with high-resolution grating spectrometers. Most of the grating detected outflows have been observed multiple times. In these cases, the absorption spectrum changes are indicating that variability is common among these high-velocity winds. In this paper we revisit the grating observations of PG 1211+143, and PDS 456, and report preliminary results on 4C 74.26. We discuss the spectral variability of the first two sources and its implications to the outflows.

Kaspi, Shai; Behar, Ehud

2010-12-01

240

Monolithic micro-spectrometer for low-cost sensing in materials processing  

Microsoft Academic Search

We have developed a monolithic micro-spectrometer suitable for a variety of sensing applications including industrial process monitoring. The device consists of a solid structure with a volume less than 6 cubic centimeters. All optical components of the spectrometer including two aspheric mirrors, a diffraction grating, and entrance and exit surfaces are fabricated onto the surface of the structure. All light

C. M. Egert; S. Rajic

1997-01-01

241

Gas Detection with a Micro FTIR Spectrometer in the MIR Region  

Microsoft Academic Search

We report on the application of a silicon micromachined lamellar grating interferometer in a Fourier Transform Infrared (FTIR) spectrometer for the detection of gases in the mid-infrared (MIR) region. The FTIR spectrometer was equipped with MIR optical fibers for light coupling. Gas measurements in the MIR region were focused on specific gases (CO2, CH4) in order to determine the limit

T. Scharf; D. Briand; S. Bühler; O. Manzardo; H. P. Herzig; N. F. de Rooij

2009-01-01

242

In-orbit performance of the spectrometers of the Extreme Ultraviolet Explorer  

Microsoft Academic Search

The Extreme Ultraviolet Explorer (EUVE), launched on June 7, 1992, is an extremely successful NASA astrophysics mission that contains three extreme ultraviolet (EUV) spectrometers designed to be used in pointed spectroscopic observations of astrophysical sources in the 70-760 angstrom wavelength region. The spectrometers utilize a slitless design based on grazing- incidence optics and variable line-space gratings. Detailed wavelength scales determined

William T. Boyd; Patrick N. Jelinsky; David S. Finley; J. Dupuis; M. Abbott; C. Christian; Roger F. Malina

1994-01-01

243

Calibration of a VUV spectrometer-detector system using synchrotron radiation  

Microsoft Academic Search

Synchrotron light is presently used as the primary intensity standard for the calibration of the detection efficiency of a VUV spectrometer detector system, in a novel apparatus for the measurement of absolute electron impact photoemission cross sections in the 30-150 nm range. By scanning the beam of synchrotron radiation across the surface of the spectrometer grating, a precise simulation of

A. McPherson; N. Rouze; W. B. Westerveld; J. S. Risley

1986-01-01

244

Tactile discrimination of gratings  

Microsoft Academic Search

Human subjects were required to differentiate grating surfaces of alternating grooves and ridges by moving a finger back and forth across the surface. Their discriminative capacities were measured, as well as the movement and force profiles that they selected. To measure discrimination, a forced choice paradigm was used in which three surfaces were presented on each trial. Two surfaces were

J. W. Morley; A. W. Goodwin; I. Darian-Smith

1983-01-01

245

Bragg grating rogue wave  

E-print Network

We derive the rogue wave solution of the classical massive Thirring model, that describes nonlinear optical pulse propagation in Bragg gratings. Combining electromagnetically induced transparency with Bragg scattering four-wave mixing, may lead to extreme waves at extremely low powers.

Degasperis, Antonio; Aceves, Alejandro B

2015-01-01

246

A Rowland Circle, multielement graphite furnace atomic absorption spectrometer  

Microsoft Academic Search

A simultaneous, multielement atomic absorption spectrometer utilizing a graphite furnace atomizer was constructed and evaluated. The optical arrangement employs a concave grating to combine the spectral output from a deuterium lamp and four hollow cathode lamps that are placed on the perimeter of a Rowland Circle. A graphite furnace atomizer is positioned on the circle at the point of convergence

Karl A. Wagner; James D. Batchelor; Bradley T. Jones

1998-01-01

247

Optical system for high resolution spectrometer/monochromator  

DOEpatents

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.

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

1988-01-01

248

Developing Tools for Undergraduate Spectroscopy: An Inexpensive Visible Light Spectrometer  

ERIC Educational Resources Information Center

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…

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

2013-01-01

249

Miniature lamellar grating interferometer based on silicon technology  

Microsoft Academic Search

We present a lamellar grating interferometer realized with microelectromechanical system technology. It is used as a time-scanning Fourier-transform spectrometer. The motion is carried out by an electrostatic comb drive actuator fabricated by silicon micromachining, particularly by silicon-on-insulator technology. For the first time to our knowledge, we measure the spectrum of an extended white-light source with a resolution of 1.6 nm

Omar Manzardo; Roland Michaely; Felix Schädelin; Wilfried Noell; Thomas Overstolz; Nico de Rooij; Hans Peter Herzig

2004-01-01

250

Optical properties of light emitting diodes with a cascading plasmonic grating.  

PubMed

In this paper, the polarization dependent optical properties of InGaN/GaN multi-quantum wells (MQWs) LED with cascading plasmonic gratings are investigated using an angle-resolved photoluminescence (ARPL) spectrometer. The plasmonic gratings consist of two Ag gratings with a half-pitch displacement. The ARPL spectra of the TE-TM state present a broadband emission with resonance dips occasioned by the SP resonance while the TM-TE state presents resonance peaks with low sideband emission. The resonance properties can be tuned by modifying the geometric parameters of the plasmonic grating. The ARPL spectrum of the LED sample with pure GaN 1D grating is also measured and discussed. The investigated plasmonics LED represents resonance optical properties different from the conventional surface relief LED, which can be used in special applications. PMID:21164906

Wang, Chih-Ming; Tsai, Yao-Lin; Tu, Sheng-Han; Lee, Chien-Chieh; Kuo, Cheng-Huang; Chang, Jenq-Yang

2010-12-01

251

The science case of the PEPSI high-resolution echelle spectrograph and polarimeter for the LBT  

Microsoft Academic Search

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

K. G. Strassmeier; R. Pallavicini; J. B. Rice; M. I. Andersen

2004-01-01

252

The Chandra High Energy Transmission Grating: Design, Fabrication, Ground Calibration and Five Years in Flight  

E-print Network

Details of the design, fabrication, ground and flight calibration of the High Energy Transmission Grating, HETG, on the Chandra X-ray Observatory are presented after five years of flight experience. Specifics include the theory of phased transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly six years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.

Claude R. Canizares; John E. Davis; Daniel Dewey; Kathryn A. Flanagan; Eugene B. Galton; David P. Huenemoerder; Kazunori Ishibashi; Thomas H. Markert; Herman L. Marshall; Michael McGuirk; Mark L. Schattenburg; Norbert S. Schulz; Henry I. Smith; Michael Wise

2005-07-01

253

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

254

Degradation Free Spectrometers for Solar EUV Measurements  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

255

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

256

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

257

Small angle spectrometers: Summary  

SciTech Connect

Aspects of experiments at small angles at the Superconducting Super Collider are considered. Topics summarized include a small angle spectrometer, a high contingency spectrometer, dipole and toroid spectrometers, and magnet choices. (LEW)

Courant, E.; Foley, K.J.; Schlein, P.E.; Rosner, J.; Slaughter, J.; Bromberg, C.; Jones, L.; Garren, A.; Groom, D.; Johnson, D.E.

1986-01-01

258

Water cooled rolling grate incinerator  

SciTech Connect

This patent describes a water cooled roller grate incinerator cooperatively associated with a boiler. It comprises cylindrical shaped roller grates, each having a plurality of circular arrays of spaced apart cooling tubes separated by perforated webs and connected at each end to a ring header; a rotary joint associated with each cylindrical roller grate for supplying cooling fluid to the circular array of tubes to keep them cool and returning heated fluid to the boiler; each roller grate being disposed to rotate about a centrally disposed axis; the axes of the roller grates being disposed in an inclined plane generally parallel to each other so as to form an undulating surface; a waster hopper with a waste feed ram disposed on the lower end of the hopper for feeding waste to the undulating surface; a combustion air system for supplying combustion air through the perforated webs to the waste pushed on the undulating surface by the waste feed ram to burn the waste; a separate drive system for each grate, the drive system regulating the rate at which the burning waste progresses across the undulating surface portion of each grate as the grates rotate transferring the waste from one roller grate to the next lower roller grate as the waste burns.

Ettehadieh, B.

1991-08-27

259

High Efficiency Binary Blazed Grating Waveguide Couplers  

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

260

Lipid multilayer gratings  

NASA Astrophysics Data System (ADS)

The interaction of electromagnetic waves with matter can be controlled by structuring the matter on the scale of the wavelength of light, and various photonic components have been made by structuring materials using top-down or bottom-up approaches. Dip-pen nanolithography is a scanning-probe-based fabrication technique that can be used to deposit materials on surfaces with high resolution and, when carried out in parallel, with high throughput. Here, we show that lyotropic optical diffraction gratings-composed of biofunctional lipid multilayers with controllable heights between ~5 and 100 nm-can be fabricated by lipid dip-pen nanolithography. Multiple materials can be simultaneously written into arbitrary patterns on pre-structured surfaces to generate complex structures and devices, allowing nanostructures to be interfaced by combinations of top-down and bottom-up fabrication methods. We also show that fluid and biocompatible lipid multilayer gratings allow label-free and specific detection of lipid-protein interactions in solution. This biosensing capability takes advantage of the adhesion properties of the phospholipid superstructures and the changes in the size and shape of the grating elements that take place in response to analyte binding.

Lenhert, Steven; Brinkmann, Falko; Laue, Thomas; Walheim, Stefan; Vannahme, Christoph; Klinkhammer, Soenke; Xu, Miao; Sekula, Sylwia; Mappes, Timo; Schimmel, Thomas; Fuchs, Harald

2010-04-01

261

High resolution instrumentation system for fibre-Bragg grating aerospace sensors  

Microsoft Academic Search

A passive technique for high-resolution detection of the wavelength of peak reflection from fibre Bragg grating (FBG) sensors is presented. The approach, based on a de-convolution of the FBG spectrum and the spectrometer resolution, essentially overcomes the low spectral resolution (?0.1 nm) associated with commercial spectrometers employing CCD detection. The performance of two algorithms, the Centroid Detection algorithm (CDA) and

A Ezbiri; S. E Kanellopoulos; V. A Handerek

1998-01-01

262

Surface plasmon resonance based integrable micro spectrometer  

NASA Astrophysics Data System (ADS)

We propose and realize the concept of a surface plasmon resonance based integrable and planar micro spectrometer that is suitable to determine the wavelength of incident light with sub-nanometer resolution over a broad range of frequencies in the infrared, visible, and ultraviolet regime. A dielectric grating structure with an ascending effective refractive index in the direction perpendicular to the periodicity is applied on top of a 20 nm thick gold film. Monochromatic light in normal incidence excites surface plasmons at confined areas on the sample so that the transmission is reduced locally. Depending on the wavelength, this area of low transmission shifts along the grating. The spatial transmission pattern provides information on the wavelength of the incident light.

Ehlermann, Jens; Siebels, Jan; Fohrmann, Simone; Mendach, Stefan

2015-03-01

263

21 CFR 133.146 - Grated cheeses.  

Code of Federal Regulations, 2010 CFR

...133.146 Grated cheeses. (a) Description. Grated cheeses is the class of foods prepared by grinding, grating, shredding, or otherwise comminuting cheese of one variety or a mixture of two or more varieties. The cheese varieties...

2010-04-01

264

Interfacing a Two-Stage Image Intensifier Tube to an Echelle Spectrograph  

NASA Technical Reports Server (NTRS)

An Echelle spectrograph has been in use at the Marshall Space Flight Center for a number of years. Research has been carried out in the study of the internal motions of ionized gas clouds in the interstellar medium. In order to extend the ability of the spectrograph to allow investigations of the faint outer regions of the gas clouds and to make possible the initiatiion of new research programs dealing with the study of sunspots and the zodiacal light, a two-stage image intensifier tube was incorporated into the instrument. The objective of this work was to interface the image tube with the spectrograph.

Flesch, T. R.

1983-01-01

265

Supersymmetric Bragg gratings  

NASA Astrophysics Data System (ADS)

The supersymmetric (SUSY) structure of coupled-mode equations that describe scattering of optical waves in one-dimensional Bragg gratings is highlighted. This property can find applications to the synthesis of special Bragg filters and distributed-feedback (DFB) optical cavities. In particular, multiple SUSY (Darboux–Crum) transformations can be used to synthesize DFB filters with any desired number of resonances at target frequencies. As an example, we describe the design of a DFB structure with a set of equally-spaced resonances, i.e. a frequency comb transmission filter.

Longhi, Stefano

2015-04-01

266

First application close measurements applying the new hybrid integrated MEMS spectrometer  

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

267

The Berkeley EUV spectrometer for ORFEUS  

NASA Technical Reports Server (NTRS)

A novel EUV spectrometer is presented for the ORFEUS-SPAS mission. It uses a set of four varied line-space spherical diffraction gratings to obtain high-resolution spectra of point sources at wavelengths between 390 and 1200 A. The spectra are recorded with two detector units, each containing curved-surface microchannel plates and a delay-line anode-readout system. An independent optical system detects the image of the source in the entrance aperture and tracks the source as it drifts during an observation, enabling a reconstruction of the spectra postflight. The overall system performance is discussed and illustrated by synthetic spectra.

Hurwitz, M.; Bowyer, S.

1991-01-01

268

Fiber gratings for WDM devices  

Microsoft Academic Search

Fiber gratings have many applications in the telecommunications industry, especially in components for WDM systems. These include among others wavelength stabilizers for pump lasers, gain flatteners, add-drop modules, multiplexers, demultiplexers, dispersion compensators, ASE filters, Raman amplifiers and fiber laser sources. The many different applications require careful design and control of the fiber grating spectral response along with the use of

William W. Morey; Yaowen Li

2000-01-01

269

Fibre gratings and their applications  

SciTech Connect

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)

Vasil'ev, Sergei A; Medvedkov, O I; Korolev, I G; Bozhkov, A S; Kurkov, Andrei S; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2005-12-31

270

Grating Coupled Emission Processes  

NASA Astrophysics Data System (ADS)

The uncorrelated emission from individual electrons in a beam moving over a diffraction grating is a spontaneous emission, or shot noise, process. When spontaneous emission is the dominant mechanism, the total power is given by the product of the electron charge, the beam current, and a radiation resistance. However, beams with current density above a certain threshold, or beams with pulsed structure may yield power levels which exceed the shot noise limit by orders of magnitude.(J. Urata et al., Phys. Rev. Lett. 80(3), 516 (1998).) Although a detailed theoretical description of these processes is expected to be quite complex, it is possible to capture the essential details of grating coupled emission with a simple but fundamentally based set of scaling relations. These constraints relate the beam voltage, current, and ``quality'' parameters (energy spread and emittance) with the operating wavelength limit and gain threshold conditions. This talk will compare scaling law predictions with results from ongoing experiments with high brightness beams of both low energy and highly relativistic electrons.

Walsh, J. E.; Brownell, J. H.; Kimmitt, M. F.; Swartz, J. C.; Trotz, S. R.; Fernow, R.; Kirk, H.

1998-11-01

271

Process monitor gratings  

NASA Astrophysics Data System (ADS)

Despite the increasing use of advanced imaging methods to pattern chip features, process windows continue to shrink with decreasing critical dimensions. Controlling the manufacturing process within these shrinking windows requires monitor structures designed to maximize both sensitivity and robustness. In particular, monitor structures must exhibit a large, measurable response to dose and focus changes over the entire range of the critical features process window. Any process variations present fundamental challenges to the effectiveness of OPC methods, since the shape compensation assumes a repeatable process. One particular process parameter which is under increasing scrutiny is focus blur, e.g. from finite laser bandwidth, which can cause such OPC instability, and thereby damage pattern fidelity. We introduce a new type of test target called the Process Monitor Grating (PMG) which is designed for extreme sensitivity to process variation. The PMG design principle is to use assist features to zero out higher diffraction orders. We show via simulation and experiment that such structures are indeed very sensitive to process variation. In addition, PMG targets have other desirable attributes such as mask manufacturability, robustness to pattern collapse, and compatibility with standard CD metrology methods such as scatterometry. PMG targets are applicable to the accurate determination of dose and focus deviations, and in combination with an isofocal grating target, allow the accurate determination of focus blur. The methods shown in this paper are broadly applicable to the characterization of process deviations using test wafers or to the control of product using kerf structures.

Brunner, T. A.; Ausschnitt, C. P.

2007-03-01

272

Replicated arrays of hybrid elements for application in a low-cost micro-spectrometer array  

Microsoft Academic Search

We report on the fabrication and characterization of replicated hybrid elements for low-cost micro-spectrometer array applications. An array of hybrid elements, where one surface combines the fairly large dimensions of refractive microlenses with the submicron features of a diffraction grating, was successfully replicated by hot embossing. The parameters are: lens diameter=990 ?m, height=60 ?m, grating period=1 ?m, linewidth=300 nm and

S. Traut; M. Rossi; H. P. Herzig

2000-01-01

273

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

NASA Astrophysics Data System (ADS)

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.

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

2000-01-01

274

Dds-Based Fast Scan Spectrometer  

NASA Astrophysics Data System (ADS)

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.

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

2010-06-01

275

Tropospheric Emission Spectrometer and Airborne Emission Spectrometer  

NASA Technical Reports Server (NTRS)

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.

Glavich, T.; Beer, R.

1996-01-01

276

Reflectance colorimetry measurement system using scanning spectrometer with array detector  

NASA Astrophysics Data System (ADS)

A reflectance colorimetry measurement system is constructed using scanning spectrometer with array detector, and the color measurement can be achieved under 45:0 and 0:45 geometry conditions. Typically, there are two types of spectrometer for colorimetry measurement: the scanning spectrometer with single-channel detector requires point-by-point spectral reading, and the measurement is time consuming; array sensor spectrometer (multichannel spectrometer) can completes the measurement in a few milliseconds, but its spectral resolution and range are limited by the array sensor and the optical elements. This colorimetry measurement system is designed for color calibration service, it using a scanning spectrometer with array detector, which divides the board spectral measurement range into sections, and uses the array detector to measure each section respectively, thus achieving the rapid measurement of spectral data with high resolution and wide wavelength range, so as to realized fast color measurement with high precision. The array sensor of the system using a photo diode array (PDA) with 1024 pixel, having a larger dynamic range and better linearity compared to CCD. The grating is rotated with a precision rotation stage, and the rotation angle is calculated basing the parameters of grating and collimator lens, so as to stitch the spectral data of each measurement section., the measurement signal is mutated at the junction point between measurement sections, due to the rotation angle and the shape of grating efficiency curve. The theoretical analysis and experiment shows that the signal mutation at the junction point can be eliminated by comparison measurement of reflectance.

Sun, Ruoduan; Ma, Yu; Dai, Caihong; Chen, Xiaju

2013-08-01

277

Coastal Research Imaging Spectrometer  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

278

Compact transform spectrometer based on sampling a standing wave H. L. Kung, S. R. Bhalotra, J. D. Mansell and D. A. B. Miller  

E-print Network

, including Fabry-Perot interferometers,1 grating based spectrometers2 and Michelson Fourier to Fabry-Perot and grating designs. The use of a standing wave to generate the interferogram eliminates the outer border to the center. The mirror has a mechanical resonance at approximately 700 Hz. When t

Miller, David A. B.

279

COS NUV Grating Efficiency Test  

NASA Astrophysics Data System (ADS)

We will perform two more grating efficiency tests to enable better comparison of results of grating efficiency tests done on the ground with external target spectroscopic sensitivity monitoring on orbit.The GETS contains 10 NUV exposures designed to get the same S/N of various emission lines throughout the NUV band. The sequence and duration of exposures in this NUV GET are the same as used by the IDT on the ground from 2004-2009 to monitor the relative efficiencies of the NUV gratings. The sequence starts with a 20-minute wait, to ensure that the lamp has cooled from any usage in a previous visit.

Osten, Rachel

2009-07-01

280

Galileo Ultraviolet Spectrometer experiment  

Microsoft Academic Search

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

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

1992-01-01

281

Galileo Ultraviolet Spectrometer experiment  

Microsoft Academic Search

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

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

1992-01-01

282

High Accuracy Wavelength Calibration For A Scanning Visible Spectrometer  

SciTech Connect

Spectroscopic applications for plasma velocity measurements often require wavelength accuracies ? 0.2Â. 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 Â have been demonstrated. With the addition of high resolution (0.075 aresec) optical encoder on the grading stage, greater precision (~0.005 Â) 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.

Filippo Scotti and Ronald Bell

2010-07-29

283

A visible-infrared imaging spectrometer for planetary missions  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

284

Design of airborne imaging spectrometer based on curved prism  

NASA Astrophysics Data System (ADS)

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.

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

2011-11-01

285

The ACE Echelle Spectrograph - A Medium Resolution (R19,333) Fiber-fed Instrument for Meter-class and Smaller Telescopes  

NASA Astrophysics Data System (ADS)

We have designed and implemented two echelle spectrographs for a use on a 0.9-m f/7.5 and a 0.6m f/13.5 Boller & Chivens telescope. The design is readily adaptable to other optical systems. The instruments are used in a remote / robotic environment and it is easily possible to switch between spectroscopy and direct imaging in less than 10 seconds. The spectrograph is divided into three major components. The “Front End” is a module which inserts into a purpose-built filter-box / guider and is responsible for target acquisition and fiber-plate guiding as well as injection of calibration light into the fiber. The “Calibration Module” allows selection of a flat lamp, Thorium-Argon arc or a solar reference fiber. The “Optical Bench” is the actual spectrograph which is fed by a single 50 micron core diameter Polymicro fiber. We have used commercial off-the-shelf optics wherever possible. The optical path is a double-pass system. Light from the fiber passes through a Canon 200mm f/2 lens, through a cross-dispersion prism and to a 70 lines/mm reflection grating. It then returns through the prism and same lens to reach a Hamamatsu thinned back-illuminated 2048 x 512 12 micron CCD. The resulting echellogram has a total of 35 spectral orders covering the wavelength range 3800-9000A with a FWHM of 3.38A/pixel. The total efficiency of the system is around 23%. We discuss further design details and show results from both telescopes.

Mack, Peter

2013-01-01

286

Fiber Grating Environmental Sensing System  

DOEpatents

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.

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

2003-07-29

287

A Compact, Fast, Wide-Field Imaging Spectrometer System  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

288

Design of a novel noninvasive spectrometer for pesticide residues monitor  

NASA Astrophysics Data System (ADS)

Although the gas or liquid chromatography had been widely used into pesticide residues monitoring, some drawbacks such as time-consuming, complicated operation and especially the destructivity for samples were existed. To overcome the limits of destructive detection methods, the noninvasive detection method based on spectroscopy was used to detect the pesticide residues in this paper. To overcome low resolution and light-efficiency due to the drawbacks of the classical plane and holography concave gratings, a novel noninvasive spectrometer for pesticide residues monitor (PRM) based on volume holography transmission (VHT) grating was designed. Meanwhile, a custom-built splitting light system for PRM based on the VHT grating was developed. In addition, the linear charge coupled device (CCD) with combined data acquisition (DAQ) card and the virtual-PRM based on LabVIEW were respectively used as the spectral acquisition hardware and software-platform. Experimental results showed that the spectral resolution of this spectrometer reached 2nm, and the VHT grating's diffraction efficiency was gotten via the simulation experiment.

Ren, Zhong; Liu, Guodong; Huang, Zhen

2014-11-01

289

Stabilization of fiber Bragg grating laser sensor with polarization scrambling  

NASA Astrophysics Data System (ADS)

We propose a fiber Bragg grating laser sensor system for possible uses in large scale wind turbine blades' condition monitoring. The measurement instability due to the sensitive multi-wavelength lasing has been greatly improved by employing a polarization scrambling in the lasing cavity and a spectrometer demodulator. With suggested technique, we obtained 100% of data acquisition rate from all the 4 FBG laser sensors along single fiber-optic cable. Also the noise characteristics of the sensor outputs have improved 4 times more than the previous system.

Kim, Hyunjin; Kim, Dae-gil; Song, Minho

2014-05-01

290

Durable silver thin film coating for diffraction gratings  

DOEpatents

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.

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

2006-05-30

291

Lateral-Grating DFB Laser  

NASA Technical Reports Server (NTRS)

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.

Andrews, James T.; Ladany, Ivan

1991-01-01

292

High Resolution Echelle Spectroscopy of Two High Proper Motion Stars: HD 102870 and BD+20 3603  

E-print Network

In this study performed as a part of an on-going project: chemical abundance analysis of F type high proper motion (HPM) stars selected from the {\\sc ELODIE} archive. High resolution (R=42\\,000) and high signal to noise ratio (S/N=103, 36 $-$per$-$pixel) \\'{e}chelle spectra from the {\\sc ELODIE} archive for HD\\,102870 and BD\\,+20\\,3603, two representative F type HPM stars, are used to determine the fundamental parameters and photospheric abundances of 16 chemical elements including Fe and heavy slow (s)$-$ and rapid (r)$-$process elements from Y to Ba. The chemical composition and kinematic parameters of the stars imply that they belong to different Galactic populations: we report HD\\,102870, an IAU standard radial velocity star, to be a thin disk star and BD\\,+20\\,3603, a metal-poor high proper motion star, to be a halo star.

Solakci, S Oktay; Flynn, Christopher; Dervisoglu, Ahmet

2014-01-01

293

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

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

294

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

NASA Astrophysics Data System (ADS)

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.

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

2015-04-01

295

Design and applications of digital diffractive gratings  

NASA Astrophysics Data System (ADS)

This paper will report our recent works on fabrication, evaluation, and applications of gratings. We are using the Dammann parallel laser writing facility for fabrication of gratings. High-efficiency reflective gratings and large-sized grating are fabricated. We have fabricated high-power reflective laser vortex grating with expectation of a new laser drilling effect for laser fusion in the future, which is just evaluated by our developed method. These gratings are essential elements for high-power laser systems and other high-demanding metrology applications.

Zhou, Changhe; Ma, Jianyong; Wang, Jin; Yu, Junjie; Jia, Wei; Cao, Hongchao; Wu, Jun

2014-11-01

296

Near-perfect diffraction grating rhomb  

DOEpatents

A near-perfect grating rhomb enables an output beam to be diffracted to an angle offset from the input beam. The correcting grating is tipped relative to the dispersing grating to provide the offset angle. The correcting grating is further provided with a groove spacing which differs from the dispersing grating groove space by an amount effective to substantially remove angular dispersion in the output beam. A near-perfect grating rhomb has the capability for selective placement in a FEL to suppress sideband instabilities arising from the FEL.

Wantuck, Paul J. (Santa Fe, NM)

1990-01-01

297

Alignment of the Grating Wheel Mechanism for a Ground-Based, Cryogenic, Near-Infrared Astronomy Instrument  

NASA Technical Reports Server (NTRS)

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), principle investigator-class instrument for the 2.1 m and Mayall 3.8 m telescopes at Kitt Peak National Observatory, and a MEMS spectrometer concept demonstrator for the James Webb Space Telescope. 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 32 cm diameter gear. The mechanism is predominantly made of Al 6061. The grating substrates are stress relieved for enhanced cryogenic performance. The optical surfaces are replicated from off-the-shelf masters. The imaging mirror is diamond turned. The GWM spans a projected diameter of approx. 48 cm when fully assembled, utilizes several flexure designs to accommodate potential thermal gradients, and is controlled using custom software with an off-the-shelf controller. Under ambient conditions, each grating is aligned in six degrees of freedom relative to a coordinate system that is referenced to an optical alignment cube mounted at the center of the gear. The local tip/tilt (Rx/Ry) orientation of a given grating is measured using the zero-order return from an autocollimating theodolite. The other degrees of freedom are measured using a two-axis cathetometer and rotary table. Each grating's mount includes a one-piece shim located between the optic and the gear. The shim is machined to fine align each grating. We verify ambient alignment by comparing grating difractive properties to model predictions.

Gutkowski, Sharon M.; Ohl, Raymond G.; Hylan, Jason E.; Hagopian, John G.; Kraft, Stephen E.; Mentzell, J. Eric; Connelly, Joseph A.; Schepis, Joseph P.; Sparr, Leroy M.; Greenhouse, Matthew A.

2003-01-01

298

Study on the feasibility of measuring relief grating parameters through the transmission spectrum  

NASA Astrophysics Data System (ADS)

A nondestructive, accurate and fast method for measuring the grating parameters of relief gratings is proposed in this paper. At first, the 0th diffractive transmission efficiency spectrum from 600nm to 700nm is obtained according to a certain relief grating model with the rigorous coupled-wave analysis (RCWA). Under the condition of normal incidence, the 0th diffractive transmission efficiency will behave as a function of duty cycles, depths and profiles of grooves for both TE and TM polarization. Then the data of the 0th diffractive transmission efficiency spectrum for TE polarization is regarded as measured values of simulation. Finally, grating parameters are obtained with the library matching method. Theoretical analysis and numerical simulation results demonstrate the feasibility and validity of the proposed method. Being accurate, repeatable and nondestructive, this kind of method will obtain the grating parameters quickly in practice without comprehensive and expensive but only commonly spectrometer that will be convenient for measurement of grating parameters in situ.

Liu, Linyue; Chen, Xinrong; Li, Lin; Li, Chaoming; Wu, Jianhong

2014-12-01

299

Osmium coated diffraction grating in the Space Shuttle environment - Performance  

NASA Technical Reports Server (NTRS)

Samples coated with osmium were flown on the early Shuttle test flights, and on the return of these samples, the osmium coating was found to have disappeared, evidently due to the oxidation of the material in the atomic oxygen atmosphere. An instrument flown on the Spacelab 1 mission comprised an array of five spectrometers covering the extreme ultraviolet (EUV) to near-IR wavelengths. The EUV spectrometer contained an osmium-coated reflective grating located fairly deep within the instruments. Here, results of an assessment of the reflectivity and stability of the osmium surface over the course of the ten-day mission are reported. It is concluded that the osmium reflective coating remained stable relative to the spectrometer coated with MgF2 over the course of the mission. In addition, the ratio of sensitivity of these two spectrometers did not change in any major way from the time of the laboratory calibration until the time of flight two years later. Any changes are within the 50-percent calibration uncertainty.

Torr, M. R.

1985-01-01

300

Tunable optical filter of porous silicon as key component for a MEMS spectrometer  

Microsoft Academic Search

We present a microspectrometer based on a tunable interference filter for infrared or visible light that scans the desired part of the spectrum within milliseconds. A single pixel detector measures serially the intensity at selected wavelengths. This concept avoids expensive linear detectors as used for grating spectrometers. The tunable filter is fabricated by a new porous silicon technology using only

Gerhard Lammel; Sandra Schweizer; Sébastien Schiesser; Philippe Renaud

2002-01-01

301

Analysis and Experiment of Encoding Errors for MOEMS Micro Mirror Spectrometer  

Microsoft Academic Search

Micro mirror arrays used in the novel spectrometer to achieve the modulation of Hadamard transformation (HT) and spectrum detection by a single detector can also be considered as a blazed grating. During the modulation, spectrum can not be completely reflected by micro mirror array s on the “on” state. While on the “off” state, there will be still light incidence

MO Xiang-xia; WEN Zhi-yu; ZHANG Zhi-hai; GUO Yuanjun

2011-01-01

302

Contamination control and material screening for the extreme ultraviolet coronal diagnostic spectrometer on SOHO  

Microsoft Academic Search

The Coronal Diagnostic Spectrometer (CDS) to be flown on the Solar Heliospheric Observatory (SOHO) satellite makes use of both grazing and normal incidence optics operating in the extreme ultraviolet wavelength range from 15 to 80 nm. Its optical components include a Wolter Schwartzschild type 2 telescope and grazing and normal incidence reflective diffraction gratings. The instrument is thus highly sensitive

Barry J. Kent; Bruce M. Swinyard; Elizabeth L. Martin

1994-01-01

303

Equivalent networks for SAW gratings.  

PubMed

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

Koshiba, M; Mitobe, S

1988-01-01

304

Fabrication of extremely smooth blazed diffraction gratings  

E-print Network

High efficiency diffraction gratings are important in a variety of applications, such as optical telecommunications, lithography, and spectroscopy. Special interest has been placed on blazed diffraction gratings for their ...

Chang, Chih-Hao, 1980-

2004-01-01

305

A new beam steering concept: Risley gratings  

NASA Astrophysics Data System (ADS)

We introduce a new beam steering concept of the "Risley grating" that consists of independently rotating inline polarization gratings (PGs). The Risley grating concept replaces the bulky prismatic elements of the Risley prisms with thin plates containing polarization gratings, and employs their highly polarization-sensitive diffraction. As rotating two PGs, the output beam tracks within a field-of-regard (FOR), which is determined by the grating period and their relative orientations. Since PGs are typically patterned in thin liquid crystal layers (a few ?m thick), the system can be implemented with far less thickness and weight. In addition, these thin gratings can be placed with virtually zero proximity and the beam walk-off becomes negligible. We demonstrate the Risley grating that performs continuous steering with 62° FOR and 89-92% transmittance at 1550 nm wavelength. The governing equations for the steering angles of the Risley grating in the direction cosine space are also presented.

Oh, Chulwoo; Kim, Jihwan; Muth, John F.; Escuti, Michael J.

2009-08-01

306

Gratings mask bars and bars mask gratings: visual frequency response to aperiodic stimuli.  

PubMed

Gratings and bars produce unexpected mutual visual masking. A grating masks a bar much less than a bar masks a bar; and a bar masks a grating uniformly over the grating field. These effects suggest that neural populations selective for size and orientation may be involved in frequency analysis rather than in simple feature detection. PMID:5033184

Weisstein, N; Bisaha, J

1972-06-01

307

Apparatus for the carbonization of coal. [travelling grate furnace with hot gas inlets below the grate  

Microsoft Academic Search

Carbonization of coal occurs in a traveling grate furnace with hot gas inlets below the grate. A refractory screen is provided above the grate to provide a flame propagation base for the volatile gases withdrawn from the coal on the grate. The combustion zone above the refractory screen provides radiant heat to vaporize volatiles present in the coal on the

Hinkley

1976-01-01

308

Analysis of the focal pattern distortion of a cylindrical concave micro-grating in a slab waveguide and the mechanism of spatial resolution recovery  

NASA Astrophysics Data System (ADS)

With modern lithographic technology, a compact spectrometer is designed to include a blazed micro-grating with cylindrical concave grating profile. In order to restrict the sagittal beam divergence and to reduce the size of the spectrometer, the micro-grating is embedded inside a pair of planar mirrors used as a slab waveguide. In the simulations for the effect of the waveguide, we discover that the focal pattern distortion introduced by the waveguide causes a blunted and side-tailed peak in the spectrum. The distortion can be managed by allowing some gap between the edge of the waveguide and the image sensor. Such a configuration has greatly improved the resolving power of the micro-grating in this compact system.

Ko, Cheng-Hao; Lin, Jian-Shian; Chen, Nien-Po; Chen, Chang-Tai; Shen, Ji-Lin

2010-01-01

309

Optical Design of a Compact Imaging Spectrometer for Planetary Mineralogy  

NASA Technical Reports Server (NTRS)

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.

Mouroulis, Pantazis; Sellar, R. Glenn; Wilson, Daniel W.; Shea, James J.; Green, Robert O.

2007-01-01

310

Polymer Bragg gratings for wavelength division multiplexers  

Microsoft Academic Search

An advanced versatile, low-cost polymeric waveguide technology with Bragg gratings has been developed for filter applications in optical communications. Bragg gratings are photochemically formed in single mode polymeric waveguides using holographic techniques. The resulting gratings exhibit excellent filter characteristics; 99.997% reflectivity in a 2 cm grating, which corresponds to refractive index modulation of the order of 10-3, 0.2 nm width

Constantina Poga; Robert Blomquist; Louay A. Eldada; Robert A. Norwood

1999-01-01

311

Micromachined mass spectrometer  

Microsoft Academic Search

The general purpose of the present study is the realisation with silicon microtechnologies of a low cost miniature mass spectrometer working at high pressure (>1Pa). For this, two kinds of filter have been developed in our laboratory: a quadrupole mass spectrometer and a Wien filter, which is presented in this paper. The micromachined device contains on one single chip the

Nicolas Sillon; Robert Baptist

2002-01-01

312

Embedded high-contrast distributed grating structures  

DOEpatents

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.

Zubrzycki, Walter J. (Albuquerque, NM); Vawter, Gregory A. (Albuquerque, NM); Allerman, Andrew A. (Albuquerque, NM)

2002-01-01

313

Experience with spreader\\/travelling grate combustion  

Microsoft Academic Search

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

Schroth

1990-01-01

314

Advanced Fibre Bragg Grating and Microfibre Bragg Grating Fabrication Techniques  

NASA Astrophysics Data System (ADS)

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.

Chung, Kit Man

315

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

SciTech Connect

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.

Kumar, Deepak; Clayton, Daniel J.; Parman, Matthew; Stutman, Dan; Tritz, Kevin; Finkenthal, Michael [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

2012-10-15

316

Dual transmission grating based imaging radiometer for tokamak edge and divertor plasmasa)  

NASA Astrophysics Data System (ADS)

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 Å with a ˜10 Å resolution and a VUV coverage of 200-2000 Å with a ˜50 Å 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.

Kumar, Deepak; Clayton, Daniel J.; Parman, Matthew; Stutman, Dan; Tritz, Kevin; Finkenthal, Michael

2012-10-01

317

A Fourier transform spectrometer for visible and near ultra-violet measurements of atmospheric absorption  

NASA Technical Reports Server (NTRS)

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.

Parsons, C. L.; Gerlach, J. C.; Whitehurst, M.

1982-01-01

318

HiJaK: the high-resolution J, H and K spectrometer  

NASA Astrophysics Data System (ADS)

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.

Muirhead, Philip S.; Hall, Zachary J.; Veyette, Mark J.

2014-08-01

319

Electromagnetically induced grating with maximal atomic coherence  

SciTech Connect

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.

Carvalho, Silvania A.; Araujo, Luis E. E. de [Instituto de Fisica ''Gleb Wataghin'', Universidade Estadual de Campinas, Campinas-SP, 13083-859 Sao Paulo (Brazil)

2011-10-15

320

Sound energy harvesting using an acoustic grating  

NASA Astrophysics Data System (ADS)

A sound energy harvester with an acoustic grating and a piezoelectric plate has been demonstrated. The acoustic grating consists of a metal slit grating and a thin flat metal screen. The metal slit grating can squeeze an incident acoustic wave into the air gap between the slit grating and metal screen, thus giving rise to high sound pressure and causing the metal screen to vibrate. Using the direct piezoelectric effect, the "squeezed" acoustic energy is harvested efficiently by a piezoelectric component that is mounted on the back of the metal screen.

Cui, Xiao-Bin; Huang, Cheng-Ping; Hu, Jun-Hui

2015-03-01

321

The grating as an accelerating structure  

SciTech Connect

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.

Fernow, R.C.

1991-02-01

322

[Study and design on Dyson imaging spectrometer in spectral broadband with high resolution].  

PubMed

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

Yan, Ling-Wei

2014-04-01

323

Optical apparatus for forming correlation spectrometers and optical processors  

DOEpatents

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.

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

1999-05-18

324

Optical apparatus for forming correlation spectrometers and optical processors  

DOEpatents

Optical apparatus 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.

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

1999-01-01

325

A cryogenically cooled, multidetector spectrometer for infrared astronomy  

NASA Technical Reports Server (NTRS)

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.

Witteborn, F. C.; Bregman, J. D.

1984-01-01

326

Design of a portable microfiber optic spectrometer  

NASA Astrophysics Data System (ADS)

Spectrum examination is widely used in scientific research and production. With the development of scientific research and production, the trend of spectrum examination is from indoor to outdoor in situ examination and on-line monitor. So the spectrometer is required to be more minimal. A new type of portable micro fiber spectrometer, using CCD, blaze grating, and two spherical mirror, a small dispersing system based on crossing Czerny-Turner structure, is designed based on this kind of requirement. By analyzing optical system structure, the relation among parameters of these components has been found out in order to fix basic parameters for miniaturized spectrometer; its working wavelength is 200-910nm. The entire spectrum is detected by a CCD for one time, the selection of CCD is product of Toshiba Corporation, linear charge coupled device (L.CCD) TCD1304AP, then received light signal is converted to an electrical signal. The system's hardware circuit includes CPLD, MCU, the CCD driving timing circuit, signal conditioning circuits, high-speed A/D sampling and transform timing circuit. A new kind of driving and sampling system which is high integrated for multi-channel has been designed by using CPLD (complex programmable logical device) and MCU. In this system, many function modules can be generated by logic cells inside of the CPLD chip, such as the driving pulse of CCD, the driving timing of high-speed A/D sampling converter and storage system and so on. In the end, the A/D results can be transmitted to computer by MCU for storage, processing and analysis. The CPLD is programmed in VHDL and compiled, synthesized, simulated and burned with the helping of the environment of Quartus II. The design of portable micro fiber spectrometer has the feature of wide spectrum range and high resolving power, so the system is especially suitable in the application of portable filed examination.

Tong, Jian-ping; Yang, Yang; Sui, Cheng-hua; Xu, Dang-yang; Wang, fei

2010-10-01

327

Instrument design and test results of the new all-reflection spatial heterodyne spectrometer  

NASA Technical Reports Server (NTRS)

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.

Bush, Brett C.; Cotton, Daniel M.; Vickers, James C.; Chakrabarti, Supriya

1991-01-01

328

The SAGE spectrometer  

NASA Astrophysics Data System (ADS)

The SAGE spectrometer has been constructed for in-beam nuclear structure studies. SAGE combines a Ge-detector array and an electron spectrometer for detection of -rays and internal conversion electrons, respectively, and allows simultaneous observation of both electrons and -rays emitted from excited nuclei. SAGE is set up in the Accelerator Laboratory of the University of Jyväskylä and works in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer allowing the use of the recoil-decay tagging method.

Pakarinen, J.; Papadakis, P.; Sorri, J.; Herzberg, R.-D.; Greenlees, P. T.; Butler, P. A.; Coleman-Smith, P. J.; Cox, D. M.; Cresswell, J. R.; Jones, P.; Julin, R.; Konki, J.; Lazarus, I. H.; Letts, S. C.; Mistry, A.; Page, R. D.; Parr, E.; Pucknell, V. F. E.; Rahkila, P.; Sampson, J.; Sandzelius, M.; Seddon, D. A.; Simpson, J.; Thornhill, J.; Wells, D.

2014-03-01

329

Crossed phase gratings using diffractive optical elements  

NASA Astrophysics Data System (ADS)

Diffractive optics represents a new field of optics that can extend the efficiency and design of classical optics and create a new class of optical components. It is possible to make phase gratings with very elaborate profiles. If one of these grating surfaces is laid on top of another and the gratings rotated at slight angles to each other, a new grating is created with an effective profile that varies locally. To understand the affects of this variation and the diffraction efficiency of the gratings, a determination of the location and description of the local profiles was correlated to the moire period of the crossed grating system using various techniques in conjunction with the grating models. Also, the gap between the gratings and its effects on the diffraction efficiency was determined and measured. Asymmetric intensity behavior in the first order of the crossed gratings was seen. Effectively, the diffraction efficiency of the crossed gratings yielded a response of a grating with variable blaze. Some models are proposed that create a greater asymmetric behavior. They may be useful in the area of optical computing and photonics as passive optical switching devices.

Rockward, Willie Samuel

1997-09-01

330

Development, characterization and application of compact spectrometers based on MEMS with in-plane capacitive drives  

NASA Astrophysics Data System (ADS)

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 ?m. 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.

Kenda, A.; Kraft, M.; Tortschanoff, A.; Scherf, Werner; Sandner, T.; Schenk, Harald; Luettjohann, Stephan; Simon, A.

2014-05-01

331

A novel method for fabricating an optical grating element with a fine grating pitch  

NASA Astrophysics Data System (ADS)

Optical encoders are widely used to detect the position, angle or speed in precise control systems. A rotary optical encoder mainly comprises an optical sensor and an optical grating element with a fine grating pitch. In order to improve the resolution of rotary optical encoders, the grating pitch in the optical grating element should be reduced as small as possible. That is, the pulse per revolution (ppr) in the optical grating element must be increased markedly. However, an optical grating element having over 10,000 ppr is difficult to achieve by traditional methods. In this paper, a novel method is proposed and demonstrated to replicate an optical grating element with a high ppr. Furthermore, the tiny signals generated from fine grating pitches in the optical grating element have been also measured by using a conventional optical pickup head.

Chiu, Kuo-Chi; Chang, Sheng-Li; Hsu, Ming-Fang

2008-04-01

332

The SLIM spectrometer.  

PubMed

A new spectrometer, here denoted the SLIM (simple, low-power, inexpensive, microcontroller-based) spectrometer, was developed that exploits the small size and low cost of solid-state electronic devices. In this device, light-emitting diodes (LED), single-chip integrated circuit photodetectors, embedded microcontrollers, and batteries replace traditional optoelectronic components, computers, and power supplies. This approach results in complete customizable spectrometers that are considerably less expensive and smaller than traditional instrumentation. The performance of the SLIM spectrometer, configured with a flow cell, was evaluated and compared to that of a commercial spectrophotometer. Thionine was the analyte, and the detection limit was approximately 0.2 microM with a 1.5-mm-path length flow cell. Nonlinearity due to the broad emission profile of the LED light sources is discussed. PMID:12530815

Cantrell, Kevin M; Ingle, James D

2003-01-01

333

Composite Spectrometer Prisms  

NASA Technical Reports Server (NTRS)

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.

Breckinridge, J. B.; Page, N. A.; Rodgers, J. M.

1985-01-01

334

The VIR Spectrometer  

Microsoft Academic Search

The Dawn spectrometer (VIR) is a hyperspectral spectrometer with imaging capability. The design fully accomplishes Dawn’s\\u000a scientific and measurement objectives. Determination of the mineral composition of surface materials in their geologic context\\u000a is a primary Dawn objective. The nature of the solid compounds of the asteroid (silicates, oxides, salts, organics and ices)\\u000a can be identified by visual and infrared spectroscopy

M. C. De Sanctis; A. Coradini; E. Ammannito; G. Filacchione; M. T. Capria; S. Fonte; G. Magni; A. Barbis; A. Bini; M. Dami; I. Ficai-Veltroni; G. Preti

2010-01-01

335

Study of Extra-Solar Planets with the Advanced Fiber Optic Echelle  

NASA Technical Reports Server (NTRS)

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.

Noyes, Robert W.; Boyce, Joseph M. (Technical Monitor)

2002-01-01

336

The science case of the PEPSI high-resolution echelle spectrograph and polarimeter for the LBT  

NASA Astrophysics Data System (ADS)

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.

Strassmeier, K. G.; Pallavicini, R.; Rice, J. B.; Andersen, M. I.

2004-05-01

337

The characteristics of grating structure in magnetic field measurements based on polarization properties of fiber gratings  

NASA Astrophysics Data System (ADS)

In this paper the characteristics of grating structure in magnetic field measurements based on differential group delay of fiber gratings are analyzed. Theoretical simulations are realized using the coupled-mode theory and transfer matrix method. The effects of grating parameters of uniform Bragg grating on measurement range and sensitivity are analyzed. The impacts of chirped, phase-shifted and apodized gratings on DGD peak values are also monitored. FBG transmitted spectrums and DGD spectrums are recorded by means of an optical vector analyzer (OVA). Both the simulations and experiments demonstrate that the phase-shifted gratings can obviously improve the sensitivity.

Su, Yang; Peng, Hui; Feng, Kui; Li, Yu-quan

2009-11-01

338

Cross-fiber Bragg grating transducer  

NASA Technical Reports Server (NTRS)

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.

Albin, Sacharia (Inventor); Zheng, Jianli (Inventor); Lavarias, Arnel (Inventor)

2000-01-01

339

Panel Discussion On Grating Technology  

NASA Astrophysics Data System (ADS)

CC: I would like to ask the panel four questions of general interest, and since our time is rather limited, I would like to ask you to try to limit your comments to three or four minutes. The questions are the following: 1. How would you characterize the progress of grating technology over the past 5 years, particularly in the area of theoretical analysis, experimental applications, and diagnostics? 2. What are the areas that need innovative ideas and technical break-throughs. This question is addressed more for the benefit of younger people. Suppose we have, for example, a Ph.D. student wanting to do a thesis; in what areas would you like to suggest they put their study time in? 3. What are the major problems in the grating technology community? Do they include funding, work force (are we educating enough talent in the Universities?), industrial secrecy, government assistance, international cooperation, patent protection, or any other items? 4. What actions can you suggest to promote the welfare of the grating technology community? Has it been worthwhile to come to this conference? Are there some things that we can change? What recommendations do von feel we should make?

Chi, Chang H.; Garvin, Hugh L.; Loewen, Erwin G.; Hunter, William R.; Lerner, Jeremy M.; Hutley, Michael C.

1981-02-01

340

Interlaced spin grating for optical wave filtering  

NASA Astrophysics Data System (ADS)

Interlaced spin grating is a scheme for the preparation of spectrospatial periodic absorption gratings in an inhomogeneously broadened absorption profile. It relies on the optical pumping of atoms in a nearby long-lived ground state sublevel. The scheme takes advantage of the sublevel proximity to build large contrast gratings with unlimited bandwidth and preserved average optical depth. It is particularly suited to Tm-doped crystals in the context of classical and quantum signal processing. In this paper, we study the optical pumping dynamics at play in an interlaced spin grating and describe the corresponding absorption profile shape in an optically thick atomic ensemble. We show that, in Tm:YAG, the diffraction efficiency of such a grating can reach 18.3 % in the small-angle and 11.6 % in the large-angle configuration when the excitation is made of simple pulse pairs, considerably outperforming conventional gratings.

Linget, H.; Chanelière, T.; Le Gouët, J.-L.; Berger, P.; Morvan, L.; Louchet-Chauvet, A.

2015-02-01

341

A plasmonic metal grating wavelength splitter  

NASA Astrophysics Data System (ADS)

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[? \\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[? \\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.

Yu, Yue; Sun, Chen; Li, Junhao; Deng, Xiaoxu

2015-01-01

342

Self-imaging by a volume grating  

NASA Astrophysics Data System (ADS)

The self-image phenomenon by a volume grating is proposed and theoretically analyzed. A theoretical model based on a path integral formulation to describe wave propagation through the grating inhomogeneous medium is applied. A modified version of the scalar diffraction theory Fresnel propagator is obtained which allows calculating the diffracted field amplitude by the grating. The proposed model is applied to amplitude and/or phase volume gratings. Remarkable features appear, in particular at the fractional Talbot distance 0.125 zT. In this case, if an in-phase real and imaginary grating modulation is considered a self-image intensity profile is observed for determined values of the absorptive and refractive parameters. On the other hand, a spatial comb intensity profile for a near half period shift between the real and imaginary grating modulations is found.

Forte, Gustavo; Lencina, Alberto; Tebaldi, Myrian; Bolognini, Néstor

2011-05-01

343

Optomechanical Alignment of the Grating Wheel Mechanism for a Ground-based, Cryogenic, Near-Infrared Astronomy Instrument  

NASA Technical Reports Server (NTRS)

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.

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

344

Nano-Fabricated Gratings for Electrons  

Microsoft Academic Search

This work utilizes a free-standing material grating for electron diffraction. The material grating is made of silicon nitride and coated with a 2.3 nm (plus or minus 0.3 nm) layer of gold and palladium. The grating has a periodicity of 100 nm and was fabricated at MIT. The diffraction of electrons was observed with well resolved diffraction peaks. Diffraction was

Glen Gronniger; Hong Gao; Dan Freimund; Herman Batelaan

2003-01-01

345

Asymmetric three-beam binary optic grating  

NASA Technical Reports Server (NTRS)

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.

Kathman, Alan D.; Johnson, Eric G.; Scott, Miles L.

1993-01-01

346

Focusing Diffraction Grating Element with Aberration Control  

NASA Technical Reports Server (NTRS)

Diffraction gratings are optical components with regular patterns of grooves, which angularly disperse incoming light by wavelength in a single plane, called dispersion plane. Traditional gratings on flat substrates do not perform wavefront transformation in the plane perpendicular to the dispersion plane. The device proposed here exhibits regular diffraction grating behavior, dispersing light. In addition, it performs wavelength transformation (focusing or defocusing) of diffracted light in a direction perpendicular to the dispersion plane (called sagittal plane). The device is composed of a diffraction grating with the grooves in the form of equidistant arcs. It may be formed by defining a single arc or an arc approximation, then translating it along a certain direction by a distance equal to a multiple of a fixed distance ("grating period") to obtain other groove positions. Such groove layout is nearly impossible to obtain using traditional ruling methods, such as mechanical ruling or holographic scribing, but is trivial for lithographically scribed gratings. Lithographic scribing is the newly developed method first commercially introduced by LightSmyth Technologies, which produces gratings with the highest performance and arbitrary groove shape/spacing for advanced aberration control. Unlike other types of focusing gratings, the grating is formed on a flat substrate. In a plane perpendicular to the substrate and parallel to the translation direction, the period of the grating and, therefore, the projection of its k-vector onto the plane is the same for any location on the grating surface. In that plane, no waveform transformation by the grating k-vector occurs, except of simple redirection.

Iazikov, Dmitri; Mossberg, Thomas W.; Greiner, Christoph M.

2010-01-01

347

Diffraction gratings used as identifying markers  

DOEpatents

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.

Deason, V.A.; Ward, M.B.

1991-03-26

348

Dispersive properties of planar polymer Bragg gratings  

Microsoft Academic Search

We report on the first dispersion study performed on planar Bragg gratings for WDM systems. The gratings are produced in low-loss single-mode polymeric waveguides and have a remarkable amplitude response (reflectivity >99.99%, suppressed out-of-band features). The phase response study shows that the dispersion that they introduce in a system (<100 ps\\/nm) is lower than that typical of fiber Bragg gratings

Louay Eldada; Jaymin Amin; Robert W. Sharps

2000-01-01

349

High resolution Fabry-Perot spectrometer for infrared astronomy.  

PubMed

A partly cryogenic Fabry-Perot interferometer with a spectral resolution of 10(5) for the 10-microm atmospheric window is described. It consists of a series of two etalons with ZnSe plates, one of which is cooled, and a cooled grating spectrometer with a Si:As detector. The logic of its design is discussed, and details are given of the parts which are special for the ir wavelength region. Preliminary data on the performance indicate that the instrument meets the specifications. PMID:20208793

van der Wal, P B; Slingerland, J

1979-03-01

350

Polarization Measurements on SUMI's TVLS Gratings  

NASA Technical Reports Server (NTRS)

We present measurements of toroidal variable-line-space (TVLS) gratings for the Solar Ultraviolet Magnetograph Investigation (SUMI), currently being developed an the National Space Science and Technology Center (NSSTC). SUMI zs a spectro-polarimeter designed no measure magnetic fields in the solar chromosphere by observing two UV emission lines sensitive to magnetic fields, the C-IV line at 155nm and the Mg-II 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 MgF2 coated gratings, at both linear polarizations.

Kobayashi, K.; West, E. A.; Davis, J. M.; Gary, G. A.

2007-01-01

351

Developing ultrafast laser inscribed volume gratings  

NASA Astrophysics Data System (ADS)

Due to their high efficiency and broad operational bandwidths, volume phase holographic gratings (VPHGs) are often the grating technology of choice for astronomical instruments, but current VPHGs exhibit a number of drawbacks including limits on their size, function and durability due to the manufacturing process. VPHGs are also generally made using a dichromated gelatine substrate, which exhibits reduced transmission at wavelengths longer than ~2.2 ?m, limiting their ability to operate further into the mid-infrared. An emerging alternative method of manufacturing volume gratings is ultrafast laser inscription (ULI). This technique uses focused ultrashort laser pulses to induce a localised refractive index modification inside the bulk of a substrate material. We have recently demonstrated that ULI can be used to create volume gratings for operation in the visible, near-infrared and mid-infrared regions by inscribing volume gratings in a chalcogenide glass. The direct-write nature of ULI may then facilitate the fabrication of gratings which are not restricted in terms of their size and grating profile, as is currently the case with gelatine based VPHGs. In this paper, we present our work on the manufacture of volume gratings in gallium lanthanum sulphide (GLS) chalcogenide glass. The gratings are aimed at efficient operation at wavelengths around 1 ?m, and the effect of applying an anti-reflection coating to the substrate to reduce Fresnel reflections is studied.

MacLachlan, David G.; Choudhury, Debaditya; Arriola, Alexander; Cunningham, Colin; Thomson, Robert R.; Kirkham, Andrew; Lee, David

2014-07-01

352

Reciprocating grate systems for furnaces and incinerators  

SciTech Connect

A new and improved reciprocating grate system for furnaces and incinerators wherein the system is advantageously constructed to accomplish a variety of objectives. Adjacent flights of adjacent portions of the composite grate structure reciprocate back and forth and the speed and stroke of such reciprocation can be ganged, coupled, or independently controlled. The individual grates themselves are advantageously configured for suitable spreading and air mixture relative to debris advancement. Air seals are provided and batch feed is accommodated. Grate frame reciprocation is accommodated by fluid control means, either hydraulic or pneumatic, and features are provided for enabling appropriate adjustment both of drive and stroke of related individual components.

John, F.C.; Taggart, G.B.; Taylor, S.R.

1984-09-18

353

Surface plasmons on zig-zag gratings.  

PubMed

Optical excitation of surface plasmons polaritons (SPPs) on a 'zig-zag diffraction grating' is explored. The fabricated silver grating consists of sub-wavelength grooves 'zig-zagged' along their length, providing a diffractive periodicity to visible radiation. SPPs propagating in the diffraction plane and scattered by an odd number of grating vectors are only excited by TE polarized radiation, whereas for TM polarized light, which also induces surface charge, SPP excitation is forbidden by the grating's broken-mirror symmetry. PMID:23188358

Constant, Thomas J; Taphouse, Tim S; Rance, Helen J; Kitson, Stephen C; Hibbins, Alastair P; Sambles, J Roy

2012-10-01

354

Raman-induced gratings in atomic media.  

PubMed

A novel type of electromagnetically induced gratings based on the Raman nonlinearity in the field of standing pump waves are proposed. Unlike electromagnetically induced absorption gratings, these gratings are based on the spatial modulation of Raman susceptibility. We present a theoretical study of the optical response of such a spatial periodically modulated three-level atomic medium. It is shown that transmission and reflection of a probe Raman wave can be simultaneously amplified in the grating. Transmission and reflection spectra can be controlled by varying the pump field intensity. The basic mechanism responsible for all-optical control of transmission and reflection in the samples of Raman driven atoms are discussed. PMID:24876018

Arkhipkin, V G; Myslivets, S A

2014-06-01

355

The diffraction grating - An opinionated appraisal.  

NASA Technical Reports Server (NTRS)

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.

Harrison, G. R.

1973-01-01

356

Hybrid fiber Bragg grating\\/long period fiber grating sensor for strain\\/temperature discrimination  

Microsoft Academic Search

We demonstrate a novel sensor which uses the difference in strain and temperature response of fiber Bragg gratings and a long period fiber grating to discriminate between strain and temperature induced wavelength shifts. Sensor interrogation is performed entirely on the fiber Bragg grating reflection signals. Strain and temperature were simultaneously measured to ±9 ?strain and ±1.5°C over a wide range

H. J. Patrick; G. M. Williams; A. D. Kersey; J. R. Pedrazzani; A. M. Vengsarkar

1996-01-01

357

Composition of the Venus mesosphere measured by Solar Occultation at Infrared on board Venus Express  

Microsoft Academic Search

Solar Occultation at Infrared (SOIR), which is a part of the Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) instrument on board Venus Express, combines an echelle-grating spectrometer with an acoustooptical tunable filter. It performs solar occultation measurements in the IR region at a high spectral resolution better than all previously flown planetary spectrometers. The wavelength range

A. C. Vandaele; M. De Mazière; R. Drummond; A. Mahieux; E. Neefs; V. Wilquet; O. Korablev; A. Fedorova; D. Belyaev; F. Montmessin; J.-L. Bertaux

2008-01-01

358

Active resonant subwavelength grating devices for high speed spectroscopic sensing  

NASA Astrophysics Data System (ADS)

In this paper, we describe progress towards a multi-color spectrometer and radiometer based upon an active resonant subwavelength grating (RSG). This active RSG component acts as a tunable high-speed optical filter that allows device miniaturization and ruggedization not realizable using current sensors with conventional bulk optics. Furthermore, the geometrical characteristics of the device allow for inherently high speed operation. Because of the small critical dimensions of the RSG devices, the fabrication of these sensors can prove challenging. However, we utilize the state-of-the-art capabilities at Sandia National Laboratories to realize these subwavelength grating devices. This work also leverages previous work on passive RSG devices with greater than 98% efficiency and ~1nm FWHM. Rigorous coupled wave analysis has been utilized to design RSG devices with PLZT, PMN-PT and BaTiO3 electrooptic thin films on sapphire substrates. The simulated interdigitated electrode configuration achieves field strengths around 3×107 V/m. This translates to an increase in the refractive index of 0.05 with a 40V bias potential resulting in a 90% contrast of the modulated optical signal. We have fabricated several active RSG devices on selected electro-optic materials and we discuss the latest experimental results on these devices with variable electrostatic bias and a tunable wavelength source around 1.5?m. Finally, we present the proposed data acquisition hardware and system integration plans.

Gin, A. V.; Kemme, S. A.; Boye, R. R.; Peters, D. W.; Ihlefeld, J. F.; Briggs, R. D.; Wendt, J. R.; Marshall, L. H.; Carter, T. R.; Samora, S.

2009-02-01

359

21 CFR 133.147 - Grated American cheese food.  

Code of Federal Regulations, 2010 CFR

... (2) Grated American cheese food contains not less than 23 percent...of the grated American cheese food. (4) An acidifying agent...5) Salt. (6) Artificial coloring. (d) The name of the food is “Grated American cheese...

2010-04-01

360

21 CFR 133.147 - Grated American cheese food.  

Code of Federal Regulations, 2011 CFR

... (2) Grated American cheese food contains not less than 23 percent...of the grated American cheese food. (4) An acidifying agent...5) Salt. (6) Artificial coloring. (d) The name of the food is “Grated American cheese...

2011-04-01

361

Fiber optic diffraction grating maker  

DOEpatents

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.

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

1991-01-01

362

Fiber optic diffraction grating maker  

DOEpatents

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.

Deason, V.A.; Ward, M.B.

1991-05-21

363

Fiber optic diffraction grating maker  

SciTech Connect

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. 4 figs.

Deason, V.A.; Ward, M.B.

1989-08-03

364

Mass Spectrometer Simulator  

NSDL National Science Digital Library

From the Colby College Chemistry Department, this tutorial will help visitors understand what happens inside a mass spectrometer. Users are able to select various parts of the instrument to learn and see what happens inside: the vaporization chamber, the ionization chamber, the accelerator plates, the curved chamber, and the detector. Shockwave is required to use the learning activity.

Mundy, Bradford P., 1938-

365

The VIR Spectrometer  

NASA Astrophysics Data System (ADS)

The Dawn spectrometer (VIR) is a hyperspectral spectrometer with imaging capability. The design fully accomplishes Dawn’s scientific and measurement objectives. Determination of the mineral composition of surface materials in their geologic context is a primary Dawn objective. The nature of the solid compounds of the asteroid (silicates, oxides, salts, organics and ices) can be identified by visual and infrared spectroscopy using high spatial resolution imaging to map the heterogeneity of asteroid surfaces and high spectral resolution spectroscopy to determine the composition unambiguously. The VIR Spectrometer—covering the range from the near UV (0.25 ?m) to the near IR (5.0 ?m) and having moderate to high spectral resolution and imaging capabilities—is the appropriate instrument for the determination of the asteroid global and local properties. VIR combines two data channels in one compact instrument. The visible channel covers 0.25-1.05 ?m and the infrared channel covers 1-5.0 ?m. VIR is inherited from the VIRTIS mapping spectrometer (Coradini et al. in Planet. Space Sci. 46:1291-1304, 19989; Reininger et al. in Proc. SPIE 2819:66-77, 1996) on board the ESA Rosetta mission. It will be operated for more than 2 years and spend more than 10 years in space.

de Sanctis, M. C.; Coradini, A.; Ammannito, E.; Filacchione, G.; Capria, M. T.; Fonte, S.; Magni, G.; Barbis, A.; Bini, A.; Dami, M.; Ficai-Veltroni, I.; Preti, G.

2011-12-01

366

Mass spectrometer mixture calibrations  

Microsoft Academic Search

Mass spectrometric analyses of hydrogen isotope mixtures can be difficult to make for a number of reasons. The most difficult problem is the possibility of confronting extremely great and extremely small relative mass differences in the same analysis. Commercial mass spectrometers are now available that can overcome these problems. The analytical capabilities and limitations of these instruments will be discussed.

Hicks

1986-01-01

367

Cyclotrons as mass spectrometers  

SciTech Connect

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.

Clark, D.J.

1984-04-01

368

Dual Beam Spectrometer  

NSDL National Science Digital Library

This Quick Time movie describes the operation of a dual beam spectrometer using an optical wedge to improve the accuracy of the absorbance measurement. The movie includes narration and graphs which explain the technological concepts involved. Running time for the movie is 3 minutes and 55 seconds.

Chasteen, Thomas G.

369

Tilt sensitivity of the two-grating interferometer  

SciTech Connect

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.

Anderson, Christopher N.; Naulleau, Patrick P.

2008-01-30

370

Improved LIBS limit of detection of Be, Mg, Si, Mn, Fe and Cu in aluminum alloy samples using a portable Echelle spectrometer with ICCD camera  

Microsoft Academic Search

Laser-induced breakdown spectroscopy (LIBS) is a laser-based technique that can provide non-intrusive, qualitative and quantitative measurement of metals in various environments. LIBS uses the plasma generated by a high-energy laser beam to prepare and excite the sample in one step. In the present work, LIBS has been applied to perform elemental analysis of six trace elements simultaneously in aluminum alloy

Walid Tawfik Y. Mohamed

2008-01-01

371

Measuring the temporal coherence of a high harmonic generation setup employing a Fourier transform spectrometer for the VUV/XUV  

NASA Astrophysics Data System (ADS)

In this experiment we used an 800 nm laser to generate high-order harmonics in a gas cell filled with Argon. Of those photons, a harmonic with 42 eV was selected by using a time-preserving grating monochromator. Employing a modified Mach-Zehnder type Fourier transform spectrometer for the VUV/XUV it was possible to measure the temporal coherence of the selected photons to about 6 fs. We demonstrated that not only could this kind of measurement be performed with a Fourier transform spectrometer, but also with some spatial resolution without modifying the XUV source or the spectrometer.

Terschlüsen, J. A.; Agåker, M.; Svanqvist, M.; Plogmaker, S.; Nordgren, J.; Rubensson, J.-E.; Siegbahn, H.; Söderström, J.

2014-12-01

372

[Integration design and diffraction characteristics analysis of prism-grating-prism].  

PubMed

Prism-grating-prism (PGP) module is the important dispersing component in the hyper spectral imager. In order to effectively predict the distribution of diffraction efficiency of the whole PGP component and its diffraction characteristics before fabrication, a method of the PGP integration design is proposed. From the point of view of the volume phase holographic grating (VPHG) design, combined with the restrictive correlation between the various parameters of prisms and grating, we compiled the analysis software for calculating the whole PGP's diffraction efficiency. Furthermore, the effects of the structure parameters of prisms and grating on the PGP's diffraction characteristics were researched in detail. In particular we discussed the Bragg wavelength shift behaviour of the grating and a broadband PGP spectral component with high diffraction efficiency was designed for the imaging spectrometers. The result of simulation indicated that the spectral bandwidth of the PGP becomes narrower with the dispersion coefficient of prism 1 material decreasing; Bragg wavelength shift characteristics broaden the bandwidth of VPHG both spectrally and angularly, higher angular selectivity is desirable for selection requirements of the prism 1 material, and it can be easily tuned to achieve spectral bandwidth suitable for imaging PGP spectrograph; the vertex angle of prism 1, the film thickness and relative permittivity modulation of the grating have a significant impact on the distribution of PGP's diffraction efficiency, so precision control is necessary when fabrication. The diffraction efficiency of the whole PGP component designed by this method is no less than 50% in the wavelength range from 400 to 1000 nm, the specific design parameters have been given in this paper that have a certain reference value for PGP fabrication. PMID:24783576

He, Tian-Bo; Bayanheshig; Li, Wen-Hao; Kong, Peng; Tang, Yu-Guo

2014-01-01

373

III-Nitride grating grown on freestanding HfO2 gratings  

PubMed Central

We report here the epitaxial growth of III-nitride material on freestanding HfO2 gratings by molecular beam epitaxy. Freestanding HfO2 gratings are fabricated by combining film evaporation, electron beam lithography, and fast atom beam etching of an HfO2 film by a front-side silicon process. The 60-?m long HfO2 grating beam can sustain the stress change during the epitaxial growth of a III-nitride material. Grating structures locally change the growth condition and vary indium composition in the InGaN/GaN quantum wells and thus, the photoluminescence spectra of epitaxial III-nitride grating are tuned. Guided mode resonances are experimentally demonstrated in fabricated III-nitride gratings, opening the possibility to achieve the interaction between the excited light and the grating structure through guided mode resonance. PACS: 78.55.Cr; 81.65.Cf; 81.15.Hi. PMID:21849084

2011-01-01

374

Plasmon Based Grating Gate Terahertz Detector  

Microsoft Academic Search

Double quantum well grating gate detectors have recently emerged as a widely tunable detector of millimeter wave to THz radiation. A typical device consists of source and drain contacts along with a grating gate which both modulates the carrier density and couples in the free space radiation to the plasmon modes of the double quantum well heterostructure. In a resonant

E. A. Shaner

2005-01-01

375

Photoelectrical encoder employing an optical grating  

Microsoft Academic Search

A photoelectrical encoder is disclosed wherein a physical quantity is detected from brightness obtained by moving a first and a second scale. Each scale is provided thereon with an optical grating relative to each other. The grating in one of the scales is constructed such that a first signal lead-out material layer made of a light shielding conductive material, a

Kabaya

1985-01-01

376

Dynamical theory of diffraction on moving grating  

E-print Network

In the framework of the approximation of slowly varying amplitudes a multiwave dynamical theory of neutron diffraction on a moving phase grating was developed. The influence of the velocity of the grating, its period and height of the slits on the discrete energy spectrum and intensity of various diffraction orders was analyzed.

Bushuev, V A; Kulin, G V

2015-01-01

377

Dynamical theory of diffraction on moving grating  

E-print Network

In the framework of the approximation of slowly varying amplitudes a multiwave dynamical theory of neutron diffraction on a moving phase grating was developed. The influence of the velocity of the grating, its period and height of the slits on the discrete energy spectrum and intensity of various diffraction orders was analyzed.

V. A. Bushuev; A. I. Frank; G. V. Kulin

2015-02-16

378

An Improved Diffraction Grating Spectroscope Experiment.  

ERIC Educational Resources Information Center

Discusses problems associated with standard diffraction grating experiments involving a diffraction grating, a straight meter stick, and a slit. Describes the use of a new spectroscope to overcome these problems using a curved scale to simplify calculations and help students obtain results from simple and straightforward measurements, thus giving…

Scherzer, Robert

1995-01-01

379

Fiber gratings in lasers and amplifiers  

Microsoft Academic Search

The emergence of UV-written fiber gratings, both short and long period, as a reliable fiber technology has revolutionized the field of active fiber devices. The advantageous properties of spectral selectivity, low insertion loss, and component ruggedness have made devices possible that would not be viable without their use. The use of fiber gratings in conjunction with erbium-doped fiber amplifiers (EDFAs),

Jean-Luc Archambault; Stephen G. Grubb

1997-01-01

380

Inquiry with Laser Printer Diffraction Gratings  

ERIC Educational Resources Information Center

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…

Van Hook, Stephen J.

2007-01-01

381

High-resolution compact Johann crystal spectrometer with the Livermore electron beam ion trap  

SciTech Connect

A compact high-resolution ({lambda}/{delta}{lambda}{approx_equal}10 000) spherically bent crystal spectrometer in the Johann geometry was recently installed and tested on the Lawrence Livermore National Laboratory SuperEBIT electron beam ion trap. The curvature of the mica (002) crystal grating allows for higher collection efficiency compared to the flat and cylindrically bent crystal spectrometers commonly used on the Livermore electron beam ion traps. The spectrometer's Johann configuration enables orientation of its dispersion plane to be parallel to the electron beam propagation. Used in concert with a crystal spectrometer, whose dispersion plane is perpendicular to the electron beam propagation, the polarization of x-ray emission lines can be measured.

Robbins, D.L.; Chen, H.; Beiersdorfer, P.; Faenov, A.Ya.; Pikuz, T.A.; May, M.J.; Dunn, J.; Smith, A.J. [Department of Physics, Morehouse College, Atlanta, Georgia 30314 (United States); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Multicharged Ions Spectra Data Center of VNIIFTRI, Mendeleevo, Moscow Region, 141570 (Russian Federation); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Department of Physics, Morehouse College, Atlanta, Georgia 30314 (United States)

2004-10-01

382

A high-resolution compact Johann crystal spectrometer with the Livermore electron beam ion trap.  

SciTech Connect

A compact high-resolution ({lambda}/{Delta}{lambda} {approx} 10000) spherically bent crystal spectrometer in the Johann geometry was recently installed and tested on the Lawrence Livermore National Laboratory SuperEBIT electron beam ion trap. The curvature of the mica (002) crystal grating allows for higher collection efficiency compared to the flat and cylindrically bent crystal spectrometers commonly used on the Livermore electron beam ion traps. The spectrometer's Johann configuration enables orientation of its dispersion plane to be parallel to the electron beam propagation. Used in concert with a crystal spectrometer, whose dispersion plane is perpendicular to the electron beam propagation, the polarization of x-ray emission lines can be measured.

Robbins, D L; Chen, H; Beiersdorfer, P; Faenov, A Y; Pikuz, T A; May, M J; Dunn, J; Smith, A J

2004-04-14

383

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

NASA Technical Reports Server (NTRS)

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.

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

384

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

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

385

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

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

386

Birefringence compensated arrayed waveguide grating  

NASA Astrophysics Data System (ADS)

In this paper we review our work on birefringence compensated arrayed waveguide grating. We elaborate on a birefringence compensation technique based on angled star couplers in arrayed waveguide grating (AWG) and discuss several demonstrations both in low-index-contrast and high-index-contrast material systems. A 16-channel AWG with 100GHz channel spacing for DWDM application is designed and fabricated in silica-based low-index-contrast waveguide. The experimental results confirm that the polarization-dependent wavelength shift (PD?) can be tuned by varying the incident/diffraction angle at the star couplers and a birefringence-free property can be achieved without additional fabrication process as compared to conventional AWG. A further validation of this technique is demonstrated in high-index-contrast silicon-on-insulator waveguide, in combination with different diffraction orders for TE and TM polarizations. A birefringence compensated silicon nanowire AWG for CWDM optical interconnects is designed and fabricated. The theoretical and experimental results show that the PD? can be reduced from 380-420nm to 0.5-3.5 nm, below 25% of the 3 dB bandwidth of the channel response in the wavelength range of 1500 to 1600nm.

Zou, Jun; Xia, Xiang; Lang, Tingting; He, Jian-Jun

2014-10-01

387

Scatterometry measurement of asymmetric gratings  

NASA Astrophysics Data System (ADS)

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.

Li, Jie; Hwu, Justin J.; Liu, Yongdong; Rabello, Silvio; Liu, Zhuan; Hu, Jiangtao

2009-12-01

388

CCMR: Vertical Coupling Grating Design  

NSDL National Science Digital Library

Since the conception of fiber-optic communication, much research has been focused on creating a more efficient and less costly means of transporting information using light signals. Photonic integrated circuits (PIC), which are analogous to electronic integrated circuits used in everyday electronics, combine numerous optical principles to facilitate the transfer of light information. A specific setback in optical information transfer is the joining of optical fibers to the PICs. Light is directed in the PIC through small channels known as waveguides which are considerably smaller than the optical fibers. Many methods have been suggested for joining fibers and PICs. Loss of light caused by reflection, scattering, and other phenomena must be minimized at the junction. Numerous suggested methods make it difficult and expensive to package the final combination of fiber and chip. One such method uses a grating that can direct light into the waveguide from a fiber aligned perpendicular to the PIC without the need for additional optical devices or cumbersome fastening methods. By altering the grating dimensions with the help of an evolutionary algorithm, coupling efficiency could potentially be very high. This simple coupling method would greatly cut packaging costs making the design very appealing for mass market applications.

Estelle, Adam

2007-08-29

389

Fabry-Perot filter using grating structures.  

PubMed

Grating structures are designed at the inner wall of the Fabry-Perot (FP) resonator to enhance the performance of an FP optical filter. The rectangular grating or triangular grating (TG) structures allows the light to be propagated effectively through the FP resonator. Attributed to the grating structures, the spectrum intensity of a FP resonator with grating structures is calculated to be 4.5-fold higher than that of a FP resonator with slot. In addition, the Q-factor of the resonant peak for a FP resonator with hybrid TG structure and two slots is 9.5-fold and 4.7-fold higher than that of a FP resonator with one slot and TG configurations, respectively. PMID:23503254

Lin, Yu-Sheng; Ho, Chong Pei; Koh, Kah How; Lee, Chengkuo

2013-03-15

390

Tropospheric and Airborne Emission Spectrometers  

NASA Technical Reports Server (NTRS)

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.

Glavich, Thomas; Beer, Reinhard

1996-01-01

391

A method of fabricating wide spectrum flat-field concave grating with compensation concave lens  

NASA Astrophysics Data System (ADS)

Flat-field concave diffraction grating is the key component of a portable grating spectrometer, which integrates three optical properties: dispersion, imaging, and flat spectral image in a single device. In recent years, fabricating concave grating has attracted much attention. However, the distance between two exposure light sources in the fabrication light system are often short, which makes it difficult to build the fabrication structure, sometimes even impossible. In order to solve this problem, two methods have been adopted. One is using special microscope objectives, but it reduces the system's ability of eliminating of aberrations. The other way is building spatial filters respectively, but this adds the difficulty of the system installing and adjustment, furthermore, it makes it impossible to fabricate wide spectrum FCDG. In this paper, a method to increase the distance between the two exposure light sources is proposed by using a compensation mirror. The use of compensation mirror can not only reduce the difficulty of fabricating grating, but also achieve results almost as better as that of the two original exposure points. We calculated the two new exposure points position with Matlab, and then performed system modeling, simulation and optimization in the Zemax software. A theoretical analysis is given to show that the proposed method can ensure the spectral image quality and greatly reduce the fabrication difficulty.

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

2014-11-01

392

Tunable External Cavity Quantum Cascade Lasers (EC-QCL): an application field for MOEMS based scanning gratings  

NASA Astrophysics Data System (ADS)

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 ?m - 12 ?m 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.

Grahmann, Jan; Merten, André; Ostendorf, Ralf; Fontenot, Michael; Bleh, Daniela; Schenk, Harald; Wagner, Hans-Joachim

2014-03-01

393

Optical Spectrometer for Measuring the Ratio of Atomic Hydrogen and Molecular Hydrogen in AN Abs  

NASA Astrophysics Data System (ADS)

At the test bench in Ferrara, we constructed an optical spectrometer that measures the relative population of the atomic and molecular hydrogen in the discharge tube of our atomic beam source (ABS). The spectrometer consists of a rotating grating, achromatic lenses, slits, and a sensitive photo-detector connected to a computer. Due to the rotation of the grating, the optical spectrum is scanned over the detector, and the intensities of hydrogen spectral lines are recorded. The intensity ratio of recorded hydrogen atomic lines to hydrogen molecular lines gives qualitative information about the degree of dissociation. With the device's high sensitivity and spectral resolution, it will be possible to monitor vacuum conditions and gas impurities in the ABS discharge tube.

Atutov, S. N.; Barion, L.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P. F.; Giordano, F.; Lenisa, P.; Stancari, M.; Statera, M.; Tomassetti, L.; Wang, M.

2005-08-01

394

Compact static imaging spectrometer combining spectral zooming capability with a birefringent interferometer.  

PubMed

A compact static birefringent imaging spectrometer (BIS) with spectral zooming capability is presented. It based on two identical Wollaston prisms and has no slit. The most significant advantage of the BIS is that we can conveniently select spectral resolution to adapt to different application requirements and greatly reduce the size of the spectral image data for capturing, saving, transferring, and processing. Also, we show this configuration blend the advantage of a grating spectrometer and a Michelson interferometer: extremely compact, robust, wide free spectral range and very high throughput. PMID:23609723

Li, Jie; Zhu, Jingping; Qi, Chun; Zheng, Chuanlin; Gao, Bo; Zhang, Yunyao; Hou, Xun

2013-04-22

395

[A digital micromirror device-based Hadamard transform near infrared spectrometer].  

PubMed

A Hadamard transform near infrared spectrometer based on a digital micromirror device was constructed. The optical signal was collected by optical fiber, a grating was used for light diffraction, a digital micromirror device (DMD) was applied instead of traditional mechanical Hadamard masks for optical modulation, and an InGaAs near infrared detector was used as the optic sensor. The original spectrum was recovered by fast Hadamard transform algrithms. The advantages of the spectrometer, such as high resolution, signal-noise-ratio, stability, sensitivity and response speed were proved by experiments, which indicated that it is very suitable for oil and food-safety applications. PMID:22250575

Liu, Jia; Chen, Fen-Fei; Liao, Cheng-Sheng; Xu, Qian; Zeng, Li-Bo; Wu, Qiong-Shui

2011-10-01

396

Plasma rotation measurement in small tokamaks using an optical spectrometer and a single photomultiplier as detector  

NASA Astrophysics Data System (ADS)

The method for plasma rotation measurement in the tokamak TCABR is reported in this article. During a discharge, an optical spectrometer is used to scan sequentially spectral lines of plasma impurities and spectral lines of a calibration lamp. Knowing the scanning velocity of the diffraction grating of the spectrometer with adequate precision, the Doppler shifts of impurity lines are determined. The photomultiplier output voltage signals are recorded with adequate sampling rate. With this method the residual poloidal and toroidal plasma rotation velocities were determined, assuming that they are the same as those of the impurity ions. The results show reasonable agreement with the neoclassical theory and with results from similar tokamaks.

Severo, J. H. F.; Nascimento, I. C.; Kuznetov, Yu. K.; Tsypin, V. S.; Galvão, R. M. O.; Tendler, M.

2007-04-01

397

Miniaturized Ion Mobility Spectrometer  

NASA Technical Reports Server (NTRS)

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.

Kaye, William J. (Inventor); Stimac, Robert M. (Inventor)

2015-01-01

398

Broadband ferromagnetic resonance spectrometer  

NASA Astrophysics Data System (ADS)

The continuous wave ferromagnetic resonance (FMR) spectrometer operating in multioctave (0.05-40 GHz) frequency range has been built to investigate the magnetic properties of thin ferromagnetic films in the temperature range of 4-420 K. The spectrometer has two probeheads: one is the X-band microwave reflection cavity used to perform express room temperature measurements and the other is an in-cryostat microstrip line probe to carry out FMR experiments covering the entire frequency range offered by the microwave source. Very uniform and stable magnetic field up to 2.4 T, temperature 4 K-420 K, and continuous frequency scan performed by an HP8722D vector network analyzer provide various modes of operation. Both probe heads are equipped with two-circle high precision goniometers to ensure accurate characterization of magnetic anisotropy and magnetostatic waves spectra recording. Use of the phase sensitive detection, utilized by magnetic field modulation at audio frequency and computer triggering of the network analyzer, enables broadband spectrometer sensitivity to be as high as 1.3×1011 spins/Oe.

Denysenkov, V. P.; Grishin, A. M.

2003-07-01

399

Anamorphic imaging spectrometer  

NASA Astrophysics Data System (ADS)

Deployment of compact hyperspectral imaging sensors on small UAVs has the potential of providing a cost-effective solution for rapid-response target detection and cueing based on time critical spectral information collected at low altitudes. To address this goal, a new compact hyperspectral imaging sensor is being developed with an anamorphic optical system that partially decouples image formation along both the spatial and spectral axes found in conventional push-broom hyperspectral imagers. This design concept benefits from a reduction in complexity over standard highperformance spectrometer optical designs while maintaining excellent aberration control and spatial and spectral distortion characteristics. The anamorphic optical system has the advantage of removing the spectrometer slit focus along the spatial axis and in turn eliminates nearly all aberrations in the front-end optics, regardless of field angle or aperture size. This paper presents results from the first prototype anamorphic imaging spectrometer, which weighs 4 pounds and is designed for operation in the Short Wave InfraRed (SWIR) spectral band over a wavelength range of 1 ?m to 1.7 ?m dictated by the uncooled InGaAs focal plane array used as the detector. The anamorphic system design will be discussed and results from characterization and field measurements will be presented.

Swanson, Rand C.; Moon, Thomas S.; Smith, Casey W.; Kehoe, Michael R.; Brown, Steven W.; Lykke, Keith R.

2008-04-01

400

Mechanical and thermal designs for an experiment on board the Space Shuttle - The Spacelab 1 spectrometer  

Microsoft Academic Search

Design efforts, testing, and post-flight check-out of the Spacelab 1 grating spectrometer are reviewed. The instrument was devised for identifying stratospheric and mesospheric molecular species in the IR bands. The data were to be gathered using limb-scanning techniques. Comprised of a pointing system, a monochromator, CCDs, electronic controls and an electrical hook-up to the Spacelab, the ensemble was custom-designed for

J. Besson

1985-01-01

401

The development and test of a deformable diffraction grating for a stigmatic EUV spectroheliometer  

NASA Technical Reports Server (NTRS)

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.

Timothy, J. Gethyn; Walker, A. B. C., Jr.; Morgan, J. S.; Huber, M. C. E.; Tondello, G.

1992-01-01

402

Arcus: The next generation of high-resolution X-ray grating spectra  

NASA Astrophysics Data System (ADS)

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 8-52Å, 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.

Smith, Randall

2014-11-01

403

Optoacoustic Solitons in Bragg Gratings  

NASA Astrophysics Data System (ADS)

Optical gap solitons, which exist due to a balance of nonlinearity and dispersion due to a Bragg grating, can couple to acoustic waves through electrostriction. This gives rise to a new species of “gap-acoustic” solitons (GASs), for which we find exact analytic solutions. The GAS consists of an optical pulse similar to the optical gap soliton, dressed by an accompanying phonon pulse. Close to the speed of sound, the phonon component is large. In subsonic (supersonic) solitons, the phonon pulse is a positive (negative) density variation. Coupling to the acoustic field damps the solitons’ oscillatory instability, and gives rise to a distinct instability for supersonic solitons, which may make the GAS decelerate and change direction, ultimately making the soliton subsonic.

Tasgal, Richard S.; Band, Y. B.; Malomed, Boris A.

2007-06-01

404

Mass spectrometers: instrumentation  

NASA Astrophysics Data System (ADS)

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.

Cooks, R. G.; Hoke, S. H., II; Morand, K. L.; Lammert, S. A.

1992-09-01

405

A multiplexed Bragg grating fiber laser sensor system  

Microsoft Academic Search

A technique for multiplexing Bragg gratings in a fiber laser arrangement is described. This technique has successfully been used to multiplex two and three Bragg gratings with very little crosstalk. The Bragg grating laser sensors were used to measure both strain and temperature. Independent strain and temperature tuning of the gratings shows no crosstalk

A. T. Alavie; S. E. Karr; A. Othonos

1993-01-01

406

Phasor Analysis of Binary Diffraction Gratings with Different Fill Factors  

ERIC Educational Resources Information Center

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…

Martinez, Antonio; Sanchez-Lopez, Ma del Mar; Moreno, Ignacio

2007-01-01

407

Fabrication Of Grating-surface-emitting Semiconductor Lasers  

Microsoft Academic Search

SUMMARY A sketch of a grating-surface-emitting (GSE) laser is shown in Fig. 1. The gratings between the gain sections provide feedback for laser oscillation in second order and couple out the laser radiation perpendicular to the surface in both directions in first order. With proper choice of grating parameters, a portion of the light is passed completely through each grating

G. A. Evans; N. W. Carlson; J. M. Hammer; D. P. Bour; J. B. Kirk; S. K. Liew; H. Lee; W. Reichert; R. K. DeFreez; C. A. Wang; H. K. Choi; J. N. Walpole; J. K. Butler

1991-01-01

408

Aplanatic and quasi-aplanatic diffraction gratings  

DOEpatents

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.

Hettrick, M.C.

1987-09-14

409

Coherence-polarization mixing in resonance gratings.  

PubMed

We show, using rigorous diffraction theory, that resonance gratings can be used to transfer partial spatial correlation to partial polarization even if the incident light beam is fully polarized. The phenomenon is based on the fact that either of the two orthogonal polarization components can be coupled into the leaky waveguide mode, leading to a strong phase delay, while the other one is reflected without being coupled into the grating. Numerical demonstrations are based on a Gaussian Schell-model beam and a grating analysis performed by rigorous Fourier modal method. PMID:22297337

Vartiainen, Ismo; Saastamoinen, Toni; Tervo, Jani; Kuittinen, Markku

2012-02-01

410

Aplanatic and quasi-aplanatic diffraction gratings  

DOEpatents

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.

Hettrick, Michael C. (Berkeley, CA)

1989-01-01

411

Fiber Bragg Grating Sensors for Harsh Environments  

PubMed Central

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

Mihailov, Stephen J.

2012-01-01

412

Talbot image of two-dimensional fractal grating  

NASA Astrophysics Data System (ADS)

Talbot effect of two-dimensional fractal grating built by square aperture arrays is studied theoretically and experimentally in this paper. The amplitude fractal gratings are produced by use of the spatial light modulator, and the diffraction intensity distributions of fractal gratings with different fractal level in Fresnel diffraction field are measured with the help of the two-dimensional CCD. Talbot images of fractal gratings with 1-level and 2-level fractal are obtained in practical experiment. The analytic expression of Fresnel diffraction intensity of the fractal gratings is derived through decomposing fractal gratings into the sum of many periodic gratings. Theoretic results predict the self-image of fractal grating reappears at some certain distance. The numerical calculations also show the Talbot image and the fractional Talbot image of fractal grating. These results may extend the application of fractal grating in the optical processing of information and laser measurement.

Teng, Shuyun; Wang, Junhong; Li, Furui; Zhang, Wei

2014-03-01

413

Compact spectrometer for on-line photon diagnostics at FLASH  

NASA Astrophysics Data System (ADS)

We present the design and characterization of a compact and portable spectrometer that has been realized to analyze in real time the high-order harmonic contents of the free-electron-laser beam at FLASH in Hamburg. The spectrometer can be installed at the end of any of the broad-band FEL beamlines at FLASH, to monitor in the single-shot operation the emissions of the fundamental FEL and the high-order harmonic content. The design is compact in order to obtain a portable instrument within a total envelope of less than one meter. It is based on the use of two flat-field grazing-incidence gratings and a EUV-enhanced CCD detector to cover the spectral range 1.7-40 nm (720-30 eV). The absolute response of the spectrometer, i.e. grating and detector efficiency, has been measured in the whole spectral region of operation. This allows to make calibrated measurements of the photon flux. Furthermore, the use of a bidimensional detector allows to measure also the angular divergence of the FEL beam in the direction parallel to the entrance slit. We present some experimental data of the FEL emissions taken at the beamline BL1 at FLASH. The high-order harmonic emissions have been characterized in terms of photon flux, temporal fluctuations and angular divergence. Measurements of the harmonics up to the 5th order at 3.8 nm have been done with the fundamental tuned at 19 nm. Measurements of the harmonics up to the 3rd order at 2.3 nm have been done with the fundamental tuned at 6.8 nm.

Frassetto, Fabio; Dziarzhytski, Siarhei; Guerassimova, Natalia; Poletto, Luca

2013-03-01

414

IR Spectrometer Using 90-degree Off-axis Parabolic Mirrors  

SciTech Connect

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.

Robert M. Malone, Richard, G. Hacking, Ian J. McKenna, and Daniel H. Dolan

2008-09-02

415

IR Spectrometer Using 90-Degree Off-Axis Parabolic Mirrors  

SciTech Connect

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.

Robert M. Malone, Ian J. McKenna

2008-03-01

416

Electromagnetic diffraction by plane reflection diffraction gratings  

NASA Technical Reports Server (NTRS)

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.

Bocker, R. P.; Marathay, A. S.

1972-01-01

417

Microfluidic droplet grating for reconfigurable optical diffraction.  

PubMed

This Letter presents a reconfigurable optical diffraction grating using multiphase droplets on a microfluidic chip. The uniform and evenly spaced circular droplets are generated by continuously dispersing two immiscible liquids into a T junction to produce plugs, which are then transformed into a circular shape at a sudden expansion of the microchannel. In experiments, the droplet grating shows a detection limit of ~6.3x10(-5) when used as an opto fl uidic refractometer and produces different colors as a color filter. Such a grating has the advantages of high stability and wide tunability in droplet size, grating period, and refractive index, making it promising for biochemical and biomaterial applications. PMID:20517452

Yu, J Q; Yang, Y; Liu, A Q; Chin, L K; Zhang, X M

2010-06-01

418

An Electronic Analog of the Diffraction Grating.  

ERIC Educational Resources Information Center

Gives an outline description of electronic circuitry which is analogous to the optical diffraction grating or to crystals used in the Bragg reflection of X-rays or electron waves, and explains how to use it. (Author/GA)

MacLeod, A. M.

1978-01-01

419

Fibre Bragg grating sensor for respiratory monitoring  

Microsoft Academic Search

A temperature sensor based on fibre Bragg gratings has been used to monitor human respiration. We discuss the thermodynamic properties of the sensor and present the general performance characteristics of the system.

Y. Liang; A. P. Mazzolini; P. R. Stoddart

2006-01-01

420

Adaptable Diffraction Gratings With Wavefront Transformation  

NASA Technical Reports Server (NTRS)

Diffraction gratings are optical components with regular patterns of grooves, which angularly disperse incoming light by wavelength. Traditional diffraction gratings have static planar, concave, or convex surfaces. However, if they could be made so that they can change the surface curvature at will, then they would be able to focus on particular segments, self-calibrate, or perform fine adjustments. This innovation creates a diffraction grating on a deformable surface. This surface could be bent at will, resulting in a dynamic wavefront transformation. This allows for self-calibration, compensation for aberrations, enhancing image resolution in a particular area, or performing multiple scans using different wavelengths. A dynamic grating gives scientists a new ability to explore wavefronts from a variety of viewpoints.

Iazikov, Dmitri; Mossberg, Thomas W.; Greiner, Christoph M.

2010-01-01

421

Multiperiod-grating surface-emitting lasers  

NASA Technical Reports Server (NTRS)

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.

Lang, Robert J. (inventor)

1992-01-01

422

Monitoring of submicrometer linewidths using diffraction gratings  

NASA Astrophysics Data System (ADS)

For a typical fabrication facility, linewidth control is done after the patterning and etch processes by means of a scanning electron microscope (SEM). Several techniques using diffraction gratings have been proposed as in-line or in situ replacements for the SEM linewidth measurement. One such system was developed for use in the Microelectronics Manufacturing Science and Technology (MMST) mini- factory. The system used in the MMST factory was capable of measuring the critical dimensions needed for factory control. This critical dimension diffraction measurement system consists of optics and processing algorithms necessary to measure a series of gratings in an etch processor or directly after processing in a metrology chamber. The optics allow the measurement of a full diffraction pattern with one image. The processing algorithms convert this image to a list of diffraction orders and intensities for each grating in the set. These are then used by the pattern matching algorithms to determine grating linewidth.

Chapados, Phillip, Jr.

1994-02-01

423

Experience with spreader/travelling grate combustion  

SciTech Connect

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.

Schroth, G. (Evt Energie-und Verfahrenstechnik GmbH, Stuttgart (DE))

1990-01-01

424

Neutron range spectrometer  

DOEpatents

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.

Manglos, S.H.

1988-03-10

425

Mossbauer spectrometer radiation detector  

NASA Technical Reports Server (NTRS)

A Mossbauer spectrometer with high efficiencies in both transmission and backscattering techniques is described. The device contains a sodium iodide crystal for detecting radiation caused by the Mossbauer effect, and two photomultipliers to collect the radiation detected by the crystal. When used in the transmission technique, the sample or scatterer is placed between the incident radiation source and the detector. When used in a backscattering technique, the detector is placed between the incident radiation source and the sample of scatterer such that the incident radiation will pass through a hole in the crystal and strike the sample. Diagrams of the instrument are provided.

Singh, J. J. (inventor)

1973-01-01

426

The design and simulation of single detector MIR spectrometer based on MEMS scanning mirror  

NASA Astrophysics Data System (ADS)

Infrared (IR) spectrometers are very important optical equipments that can be used in industry, science, medicine, agriculture, biology and food safety etc., and the market is growing. However, most traditional IR spectrometers, such as Fourier transform spectrometer (FTS) that based on Michelson interferometer principle and scanning monochromator that based on grating scanning, are expensive, relative large volume, and stationary, which can't meet the requirements of specific application such as rapidity, special environment and some special samples. To overcome these drawbacks, innovatory technology-micro electro mechanical systems (MEMS) technology was used in micro IR spectrometers in the past few years. And several prototypes and products that based on several operational principles have been emerged. In this paper, a novel IR micro spectrometer which based on MEMS technology and used single element detector was presented over a wide spectral range (from 2500nm to 5000nm) in the mid infrared (MIR) wavelength regime, and the optical system of it was designed on the basis of traditional scanning monochromator principle. In the optical system, there is a highlighted characteristic that dual spherical focus mirror was used to focus the diffraction light of the diffraction grating, which improved the spectral resolution of the optical system. Finally, using Zemax optical software, three torsion angle locations were selected to simulate the optical system of the spectrometer with the slit's size 0.1mm×1mm. The simulation result indicated that in the whole wavelength range the spectral resolution of the optical system was less than 30nm, and a high accuracy MIR spectrometer with compact volume will be realized in future hopefully.

Zhang, Zhong-wei; Wen, Zhi-yu; Zeng, Tian-ling; Wei, Kang-lin

2011-08-01

427

Efficiency enhancement of emission of terahertz radiation by optical excitation from dual grating gate HEMT  

NASA Astrophysics Data System (ADS)

We investigated the emission of terahertz radiation from a doubly interdigitated grating gates high electron mobility transistor. The experiment was performed using Fourier spectrometer system coupled with high sensitive 4 K Silicon bolometer under the vacuum. The observed emission was explained as due to the excitation of the plasma waves by means of hot 2D plasmons. We also investigated the optical stimulation of the plasma waves by subjecting the device to a CW 1.5 ?m laser beam. Dependence of the emission on the gate bias (i.e. on electron density) was observed and interpreted as due to the self oscillation of the plasma waves.

Meziani, Y. M.; Nishimura, T.; Handa, H.; Tsuda, H.; Suemitsu, T.; Knap, W.; Otsuji, T.; Sano, E.; Tsymbalov, G. M.; Popov, V. V.

2009-10-01

428

Enhancement of terahertz radiation by CW infrared laser excitation in a doubly interdigitated grating gates transistors  

NASA Astrophysics Data System (ADS)

We report on a broadband terahertz emission from a doubly interdigitated grating gates high electron mobility transistor. The observed emission was explained as due to the excitation of multi mode of plasmons: thermally excited incoherent modes and instability-driven coherent modes. The experiment was performed using Fourier spectrometer system coupled with high sensitive 4K Silicon bolometer under the vacuum. To enhance the efficiency, the device was subjected, from the backside, to a CW 1.5 ?m laser beam. Dependence of the emission on the gate bias was observed and interpreted as due to the self-oscillation of the plasma waves.

Meziani, Y. M.; Nishimura, T.; Tsuda, H.; Suemitsu, T.; Knap, W.; Popov, V. V.; Otsuji, T.

2009-11-01

429

High-resolution imaging spectrometer for recording absolutely calibrated far ultraviolet spectra from laser-produced plasmas  

SciTech Connect

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.

Brown, Charles M.; Seely, John F. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Feldman, Uri [ARTEP Inc., Ellicott City, Maryland 21042 (United States); Holland, Glenn E. [SFA Inc., 2200 Defense Highway, Suite 405, Crofton, Maryland 21114 (United States); Weaver, James L.; Obenschain, Steven P. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Kjornrattanawanich, Benjawan [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, USA and Universities Space Research Associates, Columbia, Maryland 21044 (United States); Fielding, Drew [Commonwealth Technologies Inc., 5775 Barclay Drive, Alexandria, Virginia 22315 (United States)

2008-10-15

430

Nonlinear switching in fibre Bragg gratings.  

PubMed

We report on our recent experiments on nonlinear switching in fibre Bragg gratings. Using an all-fibre source we show an increase in transmission of a FBG from 4% to 40% at high powers. This switching is associated with the formation of gap solitons inside the grating. We also demonstrate an all-optical AND gate using polarization coupled gap solitons and the optical pushbroom. PMID:19384393

Broderick, N; Taverner, D; Richardson, D

1998-11-23

431

Grating enhanced solid-state laser amplifiers  

DOEpatents

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.

Erlandson, Alvin C. (Livermore, CA); Britten, Jerald A. (Clayton, CA)

2010-11-09

432

Fibre Bragg grating for flood embankment monitoring  

NASA Astrophysics Data System (ADS)

In this article we present the preliminary studies for the flood embankment monitoring system based on the fibre Bragg gratings. The idea of the system is presented. The Bragg resonance shift is transformed to the change of the power detected by the standard InGaAs photodiode. The discrimination of the received power was executed by another fibre Bragg grating with different parameters. The project of the fully functional system is presented as well.

Markowski, Konrad; Nevar, Stanislau; Dworzanski, Adam; Hackiewicz, Krzysztof; Jedrzejewski, Kazimierz

2014-11-01

433

Diffraction characteristics of planar absorption gratings  

Microsoft Academic Search

Planar (co)sinusoidal conductivity (absorption) transmission gratings are analyzed using rigorous coupled-wave theory. The first-order and higher-order diffraction efficiencies are determined over the entire range of possible conductivities and Bragg angles of incidence (or equivalently, grating periods) for H-mode polarization incident plane waves. The maximum possible first diffracted order efficiency is found to be 5.26 percent. Rigorous results are compared to

W. E. Baird; M. G. Moharam; T. K. Gaylord

1983-01-01

434

Combined volume phase holographic gratings used as a beam splitter in near-infrared waveband  

NASA Astrophysics Data System (ADS)

With the intrinsic advantages of high diffraction efficiency, signal to noise ratio, wavelength and angle selectivity, and low scattering and absorption, volume phase holographic gratings (VPHGs) have been widely used for spectroscopy, telecommunications, astronomy and ultra-fast sciences. In this paper, a novel kind of beam splitter which is consisted of a transmission VPHG and a reflection VPHG as core components and used in near-infrared waveband is proposed. The design idea of the device is described in detail. Based on the Bragg condition and the rigorous coupled wave analysis (RCWA), diffraction properties in near-infrared waveband of the transmission and reflection VPHGs recorded in dichromated gelatin (DCG) are studied theoretically. As an example, two wavebands that need to be separated in near infrared spectrum region are taken into account. One that from 1.574?m to 1.617?m centered at 1.596?m will be diffracted by the reflection grating, and the other that from 1.636?m to 1.682?m centered at 1.659?m will be diffracted by the transmission grating. The diffraction efficiencies of the gratings are calculated and optimized by applying Kogelnik's coupled wave theory and G-solver software, respectively. The recording setup is also designed for further experiments. The effects of the recording and reconstruction setup parameters, the amplitude of the index modulation (?n) and the thickness of the gelatin layer (d), and the polarization state of reconstruction beams on the diffraction efficiency properties of the gratings are calculated and analyzed. This kind of beam splitter is prospected to be used in spectrometers for greenhouse gases monitoring.

Zhang, Xizhao; Mei, Qijing; Tang, Minxue

2014-11-01

435

Improved multiple-pass Raman spectrometer  

NASA Astrophysics Data System (ADS)

An improved Raman gain spectrometer for flame measurements of gas temperature and species concentrations is described. This instrument uses a multiple-pass optical cell to enhance the incident light intensity in the measurement volume. The Raman signal is 83 times larger than from a single pass, and the Raman signal-to-noise ratio (SNR) in room-temperature air of 153 is an improvement over that from a single-pass cell by a factor of 9.3 when the cell is operated with 100 passes and the signal is integrated over 20 laser shots. The SNR improvement with the multipass cell is even higher for flame measurements at atmospheric pressure, because detector readout noise is more significant for single-pass measurements when the gas density is lower. Raman scattering is collected and dispersed in a spectrograph with a transmission grating and recorded with a fast gated CCD array detector to help eliminate flame interferences. The instrument is used to record spontaneous Raman spectra from N2, CO2, O2, and CO in a methane--air flame. Curve fits of the recorded Raman spectra to detailed simulations of nitrogen spectra are used to determine the flame temperature from the shapes of the spectral signatures and from the ratio of the total intensities of the Stokes and anti-Stokes signals. The temperatures measured are in good agreement with radiation-corrected thermocouple measurements for a range of equivalence ratios.

Kc, Utsav; Silver, Joel A.; Hovde, David C.; Varghese, Philip L.

2011-08-01

436

Gamma ray spectrometer for ITER  

SciTech Connect

Gamma diagnostics is considered to be primary for the confined ?-particles and runaway electrons measurements on ITER. The gamma spectrometer will be embedded into a neutron dump of the ITER Neutral Particle Analyzer diagnostic complex. It will supplement NPA measurements on the fuel isotope ratio and confined alphas/fast ions. In this paper an update on ITER gamma spectrometer developments is given. A new geometry of the system is described and detailed analysis of expected signals for the spectrometer is presented.

Gin, D.; Chugunov, I.; Shevelev, A.; Khilkevitch, E.; Doinikov, D.; Naidenov, V.; Pasternak, A.; Polunovsky, I. [Ioffe Physical-Technical Institute of the Russian Academy of Sciences, Polytechnicheskaya 26, St. Petersburg, 194021 (Russian Federation); Kiptily, V. [EURATOM / CCFE Fusion Association, Abingdon, OX14 3DB (United Kingdom)

2014-08-21

437

Gamma ray spectrometer for ITER  

NASA Astrophysics Data System (ADS)

Gamma diagnostics is considered to be primary for the confined ?-particles and runaway electrons measurements on ITER. The gamma spectrometer will be embedded into a neutron dump of the ITER Neutral Particle Analyzer diagnostic complex. It will supplement NPA measurements on the fuel isotope ratio and confined alphas/fast ions. In this paper an update on ITER gamma spectrometer developments is given. A new geometry of the system is described and detailed analysis of expected signals for the spectrometer is presented.

Gin, D.; Chugunov, I.; Shevelev, A.; Khilkevitch, E.; Doinikov, D.; Naidenov, V.; Pasternak, A.; Polunovsky, I.; Kiptily, V.

2014-08-01

438

Resonant ultrasound spectrometer  

DOEpatents

An ultrasound resonant spectrometer determines the resonant frequency spectrum of a rectangular parallelepiped sample of a high dissipation material over an expected resonant response frequency range. A sample holder structure grips corners of the sample between piezoelectric drive and receive transducers. Each transducer is mounted on a membrane for only weakly coupling the transducer to the holder structure and operatively contacts a material effective to remove system resonant responses at the transducer from the expected response range. i.e., either a material such as diamond to move the response frequencies above the range or a damping powder to preclude response within the range. A square-law detector amplifier receives the response signal and retransmits the signal on an isolated shield of connecting cabling to remove cabling capacitive effects. The amplifier also provides a substantially frequency independently voltage divider with the receive transducer. The spectrometer is extremely sensitive to enable low amplitude resonance to be detected for use in calculating the elastic constants of the high dissipation sample.

Migliori, Albert (Santa Fe, NM); Visscher, William M. (Los Alamos, NM); Fisk, Zachary (Santa Fe, NM)

1990-01-01

439

SPICE EUV spectrometer for the Solar Orbiter mission  

NASA Astrophysics Data System (ADS)

SPICE is a high resolution imaging spectrometer operating at extreme ultraviolet wavelengths, 70.4 - 79.0 nm and 97.3 - 104.9 nm. It is a facility instrument on the Solar Orbiter mission. SPICE will address the key science goals of Solar Orbiter by providing the quantitative knowledge of the physical state and composition of the plasmas in the solar atmosphere, in particular investigating the source regions of outflows and ejection processes which link the solar surface and corona to the heliosphere. By observing the intensities of selected spectral lines and line profiles, SPICE will derive temperature, density, flow and composition information for the plasmas in the temperature range from 10,000 K to 10MK. The instrument optics consists of a single-mirror telescope (off-axis paraboloid operating at near-normal incidence), feeding an imaging spectrometer. The spectrometer is also using just one optical element, a Toroidal Variable Line Space grating, which images the entrance slit from the telescope focal plane onto a pair of detector arrays, with a magnification of approximately x5. Each detector consists of a photocathode coated microchannel plate image intensifier, coupled to active-pixel-sensor (APS). Particular features of the instrument needed due to proximity to the Sun include: use of dichroic coating on the mirror to transmit and reject the majority of the solar spectrum, particle-deflector to protect the optics from the solar wind, and use of data compression due to telemetry limitations.

Fludra, A.; Griffin, D.; Caldwell, M.; Eccleston, P.; Cornaby, J.; Drummond, D.; Grainger, W.; Greenway, P.; Grundy, T.; Howe, C.; McQuirk, C.; Middleton, K.; Poyntz-Wright, O.; Richards, A.; Rogers, K.; Sawyer, C.; Shaughnessy, B.; Sidher, S.; Tosh, I.; Beardsley, S.; Burton, G.; Marshall, A.; Waltham, N.; Woodward, S.; Appourchaux, T.; Philippon, A.; Auchere, F.; Buchlin, E.; Gabriel, A.; Vial, J.-C.; Schühle, U.; Curdt, W.; Innes, D.; Meining, S.; Peter, H.; Solanki, S.; Teriaca, L.; Gyo, M.; Büchel, V.; Haberreiter, M.; Pfiffner, D.; Schmutz, W.; Carlsson, M.; Haugan, S. V.; Davila, J.; Jordan, P.; Thompson, W.; Hassler, D.; Walls, B.; Deforest, C.; Hanley, J.; Johnson, J.; Phelan, P.; Blecha, L.; Cottard, H.; Paciotti, G.; Autissier, N.; Allemand, Y.; Relecom, K.; Munro, G.; Butler, A.; Klein, R.; Gottwald, A.

2013-09-01

440

Trends and future of fiber Bragg grating sensing technologies: tailored draw tower gratings (DTGs)  

NASA Astrophysics Data System (ADS)

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.

Lindner, E.; Hartung, A.; Hoh, D.; Chojetzki, C.; Schuster, K.; Bierlich, J.; Rothhardt, M.

2014-05-01

441

Case study of grate-chain degradation in a Grate-Kiln process  

NASA Astrophysics Data System (ADS)

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.

Nilsson, Erik A. A.; Pettersson, L.; Antti, M.-L.

2013-12-01

442

Photo ion spectrometer  

DOEpatents

A charged particle spectrometer is described for performing ultrasensitive quantitative analysis of selected atomic components removed from a sample. Significant improvements in performing energy and angular refocusing spectroscopy are accomplished by means of a two dimensional structure for generating predetermined electromagnetic field boundary conditions. Both resonance and non-resonance ionization of selected neutral atomic components allow accumulation of increased chemical information. A multiplexed operation between a SIMS mode and a neutral atomic component ionization mode with EARTOF analysis enables comparison of chemical information from secondary ions and neutral atomic components removed from the sample. An electronic system is described for switching high level signals, such as SIMS signals, directly to a transient recorder and through a charge amplifier to the transient recorder for a low level signal pulse counting mode, such as for a neutral atomic component ionization mode. 12 figs.

Gruen, D.M.; Young, C.E.; Pellin, M.J.

1989-12-26

443

Photo ion spectrometer  

DOEpatents

A charged particle spectrometer for performing ultrasensitive quantitative analysis of selected atomic components removed from a sample. Significant improvements in performing energy and angular refocusing spectroscopy are accomplished by means of a two dimensional structure for generating predetermined electromagnetic field boundary conditions. Both resonance and non-resonance ionization of selected neutral atomic components allow accumulation of increased chemical information. A multiplexed operation between a SIMS mode and a neutral atomic component ionization mode with EARTOF analysis enables comparison of chemical information from secondary ions and neutral atomic components removed from the sample. An electronic system is described for switching high level signals, such as SIMS signals, directly to a transient recorder and through a charge amplifier to the transient recorder for a low level signal pulse counting mode, such as for a neutral atomic component ionization mode.

Gruen, Dieter M. (Downers Grove, IL); Young, Charles E. (Westmont, IL); Pellin, Michael J. (Naperville, IL)

1989-01-01

444

Broadband Liquid Dielectric Spectrometer  

NASA Astrophysics Data System (ADS)

A dielectric spectrometer was built to measure the dielectric relaxation of proteins in solution. The dielectric cell consisted of two parallel stainless-steel electrodes (separation of 8.5 mm) embedded in PTFE. To provide temperature stability, thermally regulated water flowed through both electrodes. The cell was connected to a 4294A Precision Impedance Analyzer, providing impedance measurements from 40Hz to 110 MHz. Due to electrode polarization and high frequency parasitics, useful measurements were obtained for frequencies ranging from 10 kHz to 10 MHz. Calibration was performed using air, iso-propanol and deionized water. Experiments were also conducted on buffers and salt solutions. The dielectric relaxation of the protein beta-lactoglobulin was measured at mg/ml concentrations.

Chandra, Satyan; Arellano, Jesus; Mazzeo, Brian

2009-10-01

445

Imaging Fourier transform spectrometer  

NASA Astrophysics Data System (ADS)

Design considerations and experimental measurements from an imaging Fourier transform spectrometer are presented. The system is based on the Bomem MB-series of Fourier transform interferometer and is capable of more than 8 frames/second at 4 cm(superscript -1 apodized spectral resolution. The interferometer features dual output beams, allowing for example, the coverage of two different spectral ranges using a short-wave array and a long- wave array. The present system uses a set of two 8 X 8 InSb detector arrays to cover the 2 to 5.3 micrometers spectral range on two coaligned fields of view of 4 mrad X 4 mrad and 1 mrad X 1 mrad. Predicted noise equivalent spectral radiance as well as instrument lineshape are compared to measurements on the actual system. Particular emphasis is devoted to the behavior of the instrument lineshape with respect to off-axis position in the focal plane.

Villemaire, Andre J.; Fortin, Serge; Giroux, Jean; Smithson, Tracy; Oermann, Raymond J.

1995-06-01

446

Cryogenic Neutron Spectrometer Development  

SciTech Connect

Cryogenic microcalorimeter detectors operating at temperatures around {approx}0.1 K have been developed for the last two decades, driven mostly by the need for ultra-high energy resolution (<0.1%) in X-ray astrophysics and dark matter searches [1]. The Advanced Detector Group at Lawrence Livermore National Laboratory has developed different cryogenic detector technologies for applications ranging from X-ray astrophysics to nuclear science and non-proliferation. In particular, we have adapted cryogenic detector technologies for ultra-high energy resolution gamma-spectroscopy [2] and, more recently, fast-neutron spectroscopy [3]. Microcalorimeters are essentially ultra-sensitive thermometers that measure the energy of the radiation from the increase in temperature upon absorption. They consist of a sensitive superconducting thermometer operated at the transition between its superconducting and its normal state, where its resistance changes very rapidly with temperature such that even the minute energies deposited by single radiation quanta are sufficient to be detectable with high precision. The energy resolution of microcalorimeters is fundamentally limited by thermal fluctuations to {Delta}E{sub FWHM} {approx} 2.355 (k{sub B}T{sup 2}C{sub abs}){sup 1/2}, and thus allows an energy below 1 keV for neutron spectrometers for an operating temperature of T {approx} 0.1 K . The {Delta}E{sub FWHM} does not depend on the energy of the incident photon or particle. This expression is equivalent to the familiar (F{var_epsilon}E{sub {gamma}}){sup 1/2} considering that an absorber at temperature T contains a total energy C{sub abs}T, and the associated fluctuation are due to variations in uncorrelated (F=1) phonons ({var_epsilon} = k{sub B}T) dominated by the background energy C{sub abs}T >> E{gamma}. The rationale behind developing a cryogenic neutron spectrometer is the very high energy resolution combined with the high efficiency. Additionally, the response function is simple and the instrument is transportable. We are currently developing a fast neutron spectrometer with 0.1% energy resolution at 1 MeV neutron energy with an efficiency of > 1%. Our fast-neutron spectrometers use boron-based and {sup 6}LiF absorber crystals with Mo/Cu thermistors readout. They have achieved an energy resolution of 5.5 keV FWHM for 2.79 MeV deposited in {sup 10}B by thermal neutron capture (fig. 1), and 46 keV FWHM for fast (MeV) neutrons absorbed in {sup 6}LiF (fig. 2). Since the energy resolution does not depend on the neutron energy, we expect a similar energy resolution for MeV neutron energies. The response function is given simply by the cross section of the capture reaction, offset from zero by the Q-value of the capture reaction. This allows straightforward discrimination against gamma-events, most of which deposit less that Q{sub 6Li} = 4.79 MeV in the {sup 6}LiF absorber, and easy deconvolution of the neutron spectrum, since there is only a single capture reaction in {sup 6}Li and the spectrum is not affected by edge effects or geometric broadening. The current challenge for microcalorimeters is their necessarily small effective pixel area, {approx}1cm{sup 3} for neutron spectrometer pixels, and their slow decay time, {approx}10ms for neutron spectrometers. The pixel size is limited by the requirement for low Cabs for high energy resolution; the decay time is set by the intrinsically weak thermal coupling between materials at low temperatures. Both issues can be addressed by fabricating large detector arrays. This will enable high-precision neutron spectrometry with high statistics, such as simulated for Pu analysis in fig 3.

Niedermayr, T; Hau, I D; Friedrich, S; Burger, A; Roy, U N; Bell, Z W

2006-03-08

447

ATF beamline 1 analysis spectrometer  

SciTech Connect

We describe the design parameters and expected performance of the analysis spectrometer for beamline 1 at the BNL Accelerator Test Facility. The spectrometer should be well suited for measuring the change in energy caused by the first generation laser acceleration experiments.

Fernow, R.C.; Kirk, H.G.; Ulc, S.

1993-01-01

448

The Geostationary Fourier Transform Spectrometer  

Microsoft Academic Search

The Geostationary Fourier Transform Spectrometer (GeoFTS) is an imaging spectrometer designed for an earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. The GeoFTS instrument is a half meter cube size instrument designed to operate in geostationary orbit as a secondary “hosted” payload on a commercial geostationary satellite mission. The

Richard Key; Stanley Sander; Annmarie Eldering; David Rider; Jean-Francois Blavier; Dmitriy Bekker; Yen-Hung Wu; Ken Manatt

2012-01-01

449

Lunar orbital mass spectrometer experiment  

NASA Technical Reports Server (NTRS)

The design, development, manufacture, test and calibration of five lunar orbital mass spectrometers with the four associated ground support equipment test sets are discussed. A mass spectrometer was installed in the Apollo 15 and one in the Apollo 16 Scientific Instrument Module within the Service Module. The Apollo 15 mass spectrometer was operated with collection of 38 hours of mass spectra data during lunar orbit and 50 hours of data were collected during transearth coast. The Apollo 16 mass spectrometer was operated with collection of 76 hours of mass spectra data during lunar orbit. However, the Apollo 16 mass spectrometer was ejected into lunar orbit upon malfunction of spacecraft boom system just prior to transearth insection and no transearth coast data was possible.

Lord, W. P.

1971-01-01

450

Gold coated nano gratings for atom optics  

NASA Astrophysics Data System (ADS)

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.

Lonij, Vincent; Perreault, John; Kornilov, Oleg; Cronin, Alex

2007-06-01

451

Discrimination of auditory gratings in birds.  

PubMed

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

Osmanski, Michael S; Marvit, Peter; Depireux, Didier A; Dooling, Robert J

2009-10-01

452

Sampled chirped fiber gratings as distributed pressure sensors  

NASA Astrophysics Data System (ADS)

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.

Tjin, Swee Chuan; Mohanty, Lipi; Ngo, Nam Quoc

2004-09-01

453

Grating array systems having a plurality of gratings operative in a coherently additive mode and methods for making such grating array systems  

DOEpatents

A plurality of gratings (G1, G2) are arranged together with a wavefront sensor, actuators, and feedback system to align the gratings in such a manner, that they operate like a single, large, monolithic grating. Sub-wavelength-scale movements in the mechanical mounting, due to environmental influences, are monitored by an interferometer (28), and compensated by precision actuators (16, 18, 20) that maintain the coherently additive mode. The actuators define the grating plane, and are positioned in response to the wavefronts from the gratings and a reference flat, thus producing the interferogram that contains the alignment information. Movement of the actuators is also in response to a diffraction-limited spot on the CCD (36) to which light diffracted from the gratings is focused. The actuator geometry is implemented to take advantage of the compensating nature of the degrees of freedom between gratings, reducing the number of necessary control variables.

Kessler, Terrance J. (Mendon, NY); Bunkenburg, Joachim (Victor, NY); Huang, Hu (Pittsford, NY)

2007-02-13

454

Upper Limits on Metals in Quasar Lyman-Alpha Forest Clouds: Absence of C IV Lines in Echelle Spectra  

E-print Network

Recently Lu presented tentative evidence for C IV lines in QSO Lyman-alpha forest systems with strong lines. We have performed a similar search for C IV in our 10 km/sec echelle spectra of the bright QSO HS~1946+7658. We shifted the spectra to align the expected positions of the C IV lines in 65 Lyman-alpha systems, then added them. The resulting composite spectrum, equivalent to 390 hours of exposure time on the Lick 3-m telescope, has a signal-to-noise ratio of 80 per 0.025 Angstrom in the rest frame of the absorbers. We do not see any C IV lines down to a $2\\sigma$ limit of W$(1548) \\leq 1.4 $~m\\AA, about one-fifth of the strength of the lines seen by Lu. The C IV lines which Lu saw must be restricted to rare Lyman-alpha systems with large H I column densities $\\geq 10^{14}$~cm$^{-2}$, which are too rare to show C IV in our sample. More common Lyman-alpha systems with H I column densities of $10^{13}$ -- $10^{14}$~cm$^{-2}$ do not show C IV lines. If their ionization is H/H~I $= 10^4$ then they have [C/H] $\\leq -2.0$.

D. Tytler; X. -M. Fan

1994-01-24

455

An ultra-high-vacuum multiple grating chamber and scan drive with improved grating change  

SciTech Connect

We describe a new grating chamber and scan drive which has been designed, built, and tested by Physical Sciences Laboratory of the University of Wisconsin for the new high flux, high-resolution spectroscopy branch line of the TOK hybrid wiggler/undulator on the NSLS VUV ring. The chamber will contain spherical gratings to be used in the Spherical Grating Monochromator (SGM) configuration introduced by Chen and Sette. The grating chamber houses five 180 mm {times} 35 mm {times} 30 mm gratings capable of scanning a range of 12{degree} ({minus}14{degree} to +8{degree} with respect to the incoming beam direction) for VUV and soft X-ray diffraction. The gratings can be switched and precisely indexed while under ultra-high vacuum (UHV) at any scan angle and are mechanically isolated from the vacuum chamber to prevent inaccuracies due to chamber distortions. The gratings can separately be adjusted for height, yaw, pitch, and roll, with the latter three performed while in vacuo. The scan drive provides a resolution of 0.03 arc sec with linearity over the 12{degree} range of {approx}1.5 arc sec and absolute reproducibility of 1 arc sec. 5 refs., 5 figs.

Hulbert, S.L.; Holly, D.J.; Middleton, F.H.; Wallace, D.J. (Brookhaven National Lab., Upton, NY (USA); Wisconsin Univ., Stoughton, WI (USA). Physical Sciences Lab.; Wisconsin Univ., Stoughton, WI (USA). Synchrotron Radiation Center)

1989-01-01

456

Fabrication and characterization of the source grating for visibility improvement of neutron phase imaging with gratings  

SciTech Connect

The fabrication of gratings including metal deposition processes for highly neutron absorbing lines is a critical issue to achieve a good visibility of the grating-based phase imaging system. The source grating for a neutron Talbot-Lau interferometer is an array of Gadolinium (Gd) structures that are generally made by sputtering, photo-lithography, and chemical wet etching. However, it is very challenging to fabricate a Gd structure with sufficient neutron attenuation of approximately more than 20 {mu}m using a conventional metal deposition method because of the slow Gd deposition rate, film stress, high material cost, and so on. In this article, we fabricated the source gratings for neutron Talbot-Lau interferometers by filling the silicon structure with Gadox particles. The new fabrication method allowed us a very stable and efficient way to achieve a much higher Gadox filled structure than a Gd film structure, and is even more suitable for thermal polychromatic neutrons, which are more difficult to stop than cold neutrons. The newly fabricated source gratings were tested at the polychromatic thermal neutron grating interferometer system of HANARO at the Korea Atomic Energy Research Institute, and the visibilities and images from the neutron phase imaging system with the new source gratings were compared with those fabricated by a Gd deposition method.

Kim, Jongyul [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Nuclear and Quantum Engineering Department, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Lee, Kye Hong; Lim, Chang Hwy; Kim, Taejoo [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Ahn, Chi Won [Nano Fusion Technology Division, National Nanofab Center, Daejeon 305-701 (Korea, Republic of); Cho, Gyuseong [Nuclear and Quantum Engineering Department, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Lee, Seung Wook [School of Mechanical Engineering, Pusan National University, Pusan 609-735 (Korea, Republic of)

2013-06-15

457

Ultra-high density diffraction grating  

DOEpatents

A diffraction grating structure having ultra-high density of grooves comprises an echellette substrate having periodically repeating recessed features, and a multi-layer stack of materials disposed on the echellette substrate. The surface of the diffraction grating is planarized, such that layers of the multi-layer stack form a plurality of lines disposed on the planarized surface of the structure in a periodical fashion, wherein lines having a first property alternate with lines having a dissimilar property on the surface of the substrate. For example, in one embodiment, lines comprising high-Z and low-Z materials alternate on the planarized surface providing a structure that is suitable as a diffraction grating for EUV and soft X-rays. In some embodiments, line density of between about 10,000 lines/mm to about 100,000 lines/mm is provided.

Padmore, Howard A.; Voronov, Dmytro L.; Cambie, Rossana; Yashchuk, Valeriy V.; Gullikson, Eric M.

2012-12-11

458

Development of Aspherical Active Gratings at NSRRC  

NASA Astrophysics Data System (ADS)

An active grating based on a novel optical concept with bendable polynomial surface profile to reduce the coma and defocus aberrations had been designed and proved by the prototype testing. Due to the low glass transition temperature of the glue and the difference of thermal expansion coefficient between the 17-4 steel bender and silicon, the prototype distorted from flat polished condition when thermally de-blocked the polishing pitch. To improve the thermal deformation of the active grating in the polishing process, a new invar bender and high curing temperature glue were adapted to glue a silicon substrate on the bender. After some tests and manufacturer polishing, it showed acceptable conditions. In this paper we will present the design and preliminary tests of the invar active grating. Meanwhile, the design and analysis of a new 17-4 PH steel bender to be electro-less nickel plating and mechanical ruling for a new beamline will also be discussed.

Tseng, Tse-Chuan; Wang, Duan Jen; Perng, Shen-Yaw; Chen, Chien-Te; Lin, Chia-Jui; Kuan, Chien-Kuang; Ho, His-Chou; Wang, Jeremy; Fung, H. S.; Chang, Shuo-Hung

2007-01-01

459

Control of grating anomalies in photoactive polymers  

NASA Astrophysics Data System (ADS)

Grating formation in photoactive polymers are monitored by holographic recording. The photopolymers are based on acrylamide monomers, which are dissolved together with xanthine dyes in polyvinyl alcohol. Thin plastic coatings are obtained by casing on glass substrates. Photorecording occurs quasi-real-time and in-situ, meaning that no wet- chemical or post-thermal/photochemical processing is required. Formulations have been found, which produce large enough refractive index modulations, so that very high diffraction efficiencies can be obtained, when the recording beam angles are symmetric. Unfortunately, DEs significantly drop, when recording angles are highly asymmetric. The origin of this effect is shown to stem from grating anomalies, in that the slanted fringes bend due to nonlinear shrinkage effects during recording. The introduction of cross-linking and gelling agents stabilize the formed grating structures against dimensional distortions. These photopolymer layers have potential in photonics applications, such as holographic optical elements and waveguide structures.

Weiss, Victor; Friesem, Asher A.; Millul, Eliahu

1996-09-01

460

PASSIVE VENTILATION DETAIL (CORRESPONDS WITH METAL GRATE IN CENTER OF ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PASSIVE VENTILATION DETAIL (CORRESPONDS WITH METAL GRATE IN CENTER OF BATTERY STREET). LOOKING SOUTH AT GRATE IN SOUTHBOUND TUNNEL BORE. - Alaskan Way Viaduct and Battery Street Tunnel, Seattle, King County, WA