The rapid scanning Michelson interferometer as an infrared spectrometer in astronomy
Explore the source record for details and available documents.
Morgan, T. H.↗
SEARCH · Search NASA
Results for “infrared interferometer”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Retrieval with Infrared Atmospheric Sounding Interferometer and Validation during JAIVEx
A state-of-the-art IR-only retrieval algorithm has been developed with an all-season-global EOF Physical Regression and followed by 1-D Var. Physical Iterative Retrieval for IASI, AIRS, and NAST-I. The benefits of this retrieval are to produce atmospheric structure with a single FOV horizontal resolution (approx. 15 km for IASI and AIRS), accurate profiles above the cloud (at least) or down to the surface, surface parameters, and/or cloud microphysical parameters. Initial case study and validation indicates that surface, cloud, and atmospheric structure (include TBL) are well captured by IASI and AIRS measurements. Coincident dropsondes during the IASI and AIRS overpasses are used to validate atmospheric conditions, and accurate retrievals are obtained with an expected vertical resolution. JAIVEx has provided the data needed to validate the retrieval algorithm and its products which allows us to assess the instrument ability and/or performance. Retrievals with global coverage are under investigation for detailed retrieval assessment. It is greatly desired that these products be used for testing the impact on Atmospheric Data Assimilation and/or Numerical Weather Prediction.
Zhou, Daniel K.↗
Near-infrared spectral imaging Michelson interferometer for astronomical applications
The design and operation of an imaging Michelson interferometer-spectrometer used for near-infrared (0.8 micron to 2.5 microns) spectral imaging are reported. The system employs a rapid scan interferometer modified for stable low resolution (250/cm) performance and a 42 element PbS linear detector array. A microcomputer system is described which provides data acquisition, coadding, and Fourier transformation for near real-time presentation of the spectra of all 42 scene elements. The electronic and mechanical designs are discussed and telescope performance data presented.
Wells, C. W.↗
FIFI: The MPE Garching/UC Berkeley Far-Infrared Imaging Fabry-Perot Interferometer
We describe the performance characteristics of the MPE Garching/UC Berkeley Far-Infrared Imaging Fabry-Perot Interferometer (FIFI) for the Kuiper Airborne Observatory (KAO). The spectrometer features two or three cryogenic tunable Fabry-Perot filters in series giving spectral resolution R of up to 10(exp 5) in the range of 40 microns less than lambda less than 200 microns, and an imaging 5x5 array of photoconductive detectors with variable focal plane plate scale. The instrument works at background limited sensitivity of up to 2 x 10(exp -19) W cm(exp -2) Hz(exp -1/2) per pixel per resolution element at R = 10(exp 5) on the KAO.
Geis, Norbert↗
KALI camera - mid-infrared camera for the Keck Interferometer Nuller
We present a brief overview of the KALI Camera, the mid-infrared camera for the Keck Interferometer Nulling Project, built at the Jet Propulsion Laboratory.
Mid-infrared↗
MegaMIR: The Megapixel Mid-Infrared Instrument for the Large Binocular Telescope Interferometer
The Megapixel Mid-infrared Instrument (MegaMIR) is a proposed Fizeau-mode camera for the Large Binocular Telescope operating at wavelengths between 5 and 28 micrometers. The camera will be used in conjunction with the Large Binocular Telescope Interferometer (LBTI), a cryogenic optical system that combines the beams from twin 8.4-m telescopes in a phase coherent manner. Unlike other interferometric systems, the co-mounted telescopes on the LBT satisfy the sine condition, providing diffraction-limited resolution over the 40" field of view of the camera. With a 22.8-m baseline, MegaMIR will yield 0.1" angular resolution, making it the highest resolution wide field imager in the thermal infrared for at least the next decade. MegaMIR will utilize a newly developed 1024 x 1024 pixel Si:As detector array that has been optimized for use at high backgrounds. This new detector is a derivative of the Wide-field Infrared Survey Explorer (WISE) low-background detector. The combination of high angular resolution and wide field imaging will be a unique scientific capability for astronomy. Key benefits will be realized in planetary science, galactic, and extra-galactic astronomy. High angular resolution is essential to disentangle highly complex sources, particularly in star formation regions and external galaxies, and MegaMIR provides this performance over a full field of view. Because of the great impact being made by space observatories like the Spitzer Space Telescope, the number of available targets for study has greatly increased in recent years, and MegaMIR will allow efficient follow up science.
ultraluminous galaxies↗
Stellar Interferometry from the Ground and Space
Stellar Interferometry began more than 80 years ago with the pioneering measurement of the diameter of Betelqueuse by Michelson and Pease using a 20 foot beam mounted at the top of the 10011 Hooker telescope at Mt. Wilson. Essentially no other work was done in this field until the 1960's when Hanbury-Brown and his colleagues developed and used the Intensity Interferometer at Narrabri, Australia to measure the diameters of a number of important hot stars. The modern period of Stellar Interferometry really began in the 1970's with the successes of 3 or 4 small research groups in the US and Europe, and scientific and technical progress in the field has been outstanding, particularly in the last decade. This has lead to the development of two major ground based facilities: NASA's own Keck Interferometer and ESO's Very Large Telescope Interferometer, and a number of space interferometers such as the Space Interferometer Mission (SIM), and the Terrestrial Planet Finder (TPF), among others. I will review the principles, history, and scientific progress in the field both on the ground and in space, and I will discuss a mission concept under development here at NASA Goddard, the Fourier-Kelvin Stellar Interferometer, a near-term mid-infrared imaging interferometer, which can serve as a scientific and technical pre-cursor for some of the more ambitious concepts being discussed within the Astronomical and NASA communities.
Danchi, William C.↗
The Keck Interferometer Nuller
The Keck Interferometer Nuller (KIN), the first operational separated-aperture infrared nulling interferometer, was designed to null the mid-infrared emission from nearby stars so as to ease the measurement of faint circumstellar emission. This paper describes the basis of the KIN's four-beam, two-stage measurement approach and compares it 10 the simpler case of a two-beam nuller. In the four-beam KIN system, the starlight is first nulled in a pair of nullers operating on parallel 85 m Keck-Keck baselines, after which "cross-combination" on 4 m baselines across the Keck apertures is used to modulate and detect residual coherent off-axis emission. Comparison to the constructive itellar fringe provides calibration. The response to an extended source is similar in the two cases, except that the four-beam response includes a term due to the visibility of the source on the cross-combiner baseline-a small effect for relatively compact sources. The characteristics of the dominant null depth errors are also compared for the two cases. In the two-beam nuller, instrumental imperfections and asymmetries lead to a series of quadratic, positivedefinite null leakage terms. For the four-beam nuller, the leakage is instead a series of correlation cross-tenns combining corresponding errors in each of the two nullers, which contribute offsets only to the extent that these errors are correlated on the timescale of the measurement. This four-beam architecture has allowed a significant (approx. order of magnitude) improvement in mid-infrared long-baseline fringe-visibility accuracies.
Serabyn, E.↗
Accurate laser wavelength measurements in the infrared and far infrared using a Michelson interferometer.
Long path difference vacuum Michelson interferometer application to far IR and IR laser wavelength measurements compared with 6328 A He-Ne wavelength
Daneu, V.↗
The Fourier Kelvin Stellar Interferometer (FKSI): A Progress Report and Update
The Fourier-Kelvin Stellar Interferometer (FKSI) mission is a two-telescope infrared space interferometer with a 12.5 meter baseline on a boom, operating from 3-8 (or 10) microns, and passively cooled to about 60 K. The main goals for the mission are the measurement an characterization of the exozodiacal light around nearby stars, debris disks, and characterization of the atmospheres of known exoplanets. We discuss progress on this mission in the context of the recent call from NASA for mission concepts for the upcoming National Academy of Sciences Decadal Survey, where it is considered a medium class mission ($600-800 million) in terms of the overall budget.
Danchi, William C.↗
Spherical lamellar grating interferometer for airborne astronomical observations of far infrared objects
A lamellar-grating interferometer designed for airborne IR astronomy is described, and its response to a laboratory far-IR source and to Jupiter as viewed from NASA's Kuiper Airborne Observatory is discussed. The theory of lamellar-grating interferometers is reviewed, advantages over Michelson interferometers are noted, and the optical arrangement for the lamellar-grating instrument is indicated. The response of the instrument is illustrated using purged and unpurged spectra of a 1000-K blackbody source as well as a raw spectrum of Jupiter containing many absorption features (probably telluric) identified with rotation bands of H2O. It is noted that the interferometer's self-collimation allows for efficient operation with a minimum of auxiliary optics.
Pipher, J. L.↗
Terrestrial Planet Finder Interferometer: 2007-2008 Progress and Plans
This paper provides an overview of technology development for the Terrestrial Planet Finder Interferometer (TPF-I). TPF-I is a mid-infrared space interferometer being designed with the capability of detecting Earth-like planets in the habitable zones around nearby stars. The overall technology roadmap is presented and progress with each of the testbeds is summarized. The current interferometer architecture, design trades, and the viability of possible reduced-scope mission concepts are also presented.
formation flying↗
Assimilation of IASI and AIRS Data: Information Content and Quality Control
The Infrared Atmospheric Sounding Interferometer (IASI) and Atmospheric Infrared Sounder (AIRS) instruments have two orders of magnitude more channels that the current operational infrared sounder (High Resolution Infra-Red Sounder (HIRS)). This data volume presents a technological challenge for using the data in a data assimilation system. Data reduction will be a necessary for assimilation. It is important to understand the information content of the radiance measurements for data reduction purposes. In this talk, I will discuss issues relating to information content and quality control for assimilation of the AIRS and IASI data.
Joiner, J.↗
Alignment and Polarization Sensitivity Study on the Cassini: CIRS FIR Interferometer
The Composite InfraRed Spectrometer (CIRS) instrument flying on the Cassini spacecraft to Saturn is a cryogenic spectrometer with far-infrared (FIR) and mid-infrared (MIR) channels. The CIRS FIR channel is a polarizing interferometer that contains three polarizing grid components. These components are an input polarizer, a polarizing beamsplitter, and an output polarizer/analyzer. They consist of a 1.5 micron thick mylar substrate with 2 microns wide copper wires, with 2 microns spacing (4 microns pitch) photolithographically deposited on the substrate. This paper details the alignment sensitivity studies performed on the polarizing beamsplitter, and the polarization sensitivity studies performed on all three polarizing components in the FIR interferometer.
Crooke, Julie↗
Detecting extrasolar planets with the Keck Interferometer
We discuss the development of the Differential Phase detection technique for the Keck Interferometer Hot Jupiter Key Science Program.
infrared interferometer↗
Infrared Aerosol Radiative Forcing at the Surface and the Top of the Atmosphere
We study the clear-sky aerosol radiative forcing at infrared wavelengths using data from the Aerosol Characterization Experiment (ACE-Asia) cruise of the NOAA R/V Ronald H. Brown. Limited number of data points is analyzed mostly from ship and collocated satellite values. An optical model is derived from chemical measurements, lidar profiles, and visible extinction measurements which is used to and estimate the infrared aerosol optical thickness and the single scattering albedo. The IR model results are compared to detailed Fourier Transform Interferometer based infrared aerosol forcing estimates, pyrgeometer based infrared downward fluxes, and against the direct solar forcing observations. This combined approach attests for the self-consistency of the optical model and allows to derive quantities such as the infrared forcing at the top of the atmosphere or the infrared optical thickness. The mean infrared aerosol optical thickness at 10 microns is 0.08 and the single scattering albedo is 0.55. The modeled infrared aerosol forcing reaches 10 W/sq m during the cruise, which is a significant contribution to the total direct aerosol forcing. The surface infrared aerosol radiative forcing is between 10 to 25% of the shortwave aerosol forcing. The infrared aerosol forcing at the top of the atmosphere can go up to 19% of the solar aerosol forcing. We show good agreement between satellite (CERES instrument) retrievals and model results at the top of the atmosphere. Over the Sea of Japan, the average infrared radiative forcing is 4.6 W/sq m in the window region at the surface and it is 1.5 W/sq m at top of the atmosphere. The top of the atmosphere IR forcing efficiency is a strong function of aerosol temperature while the surface IR forcing efficiency varies between 37 and 55 W/sq m (per infrared optical depth unit). and changes between 10 to 18 W/sq m (per infrared optical depth unit).
Markowicz, Krzysztof M.↗
Imaging interferometer using dual broadband quantum well infrared photodetectors
The Jet Propulsion Laboratory is developing a new imaging interferometer that has double the efficiency of conventional interferometers and only a fraction of the mass and volume. The project is being funded as part of the Defense Advanced Research Projects Agency (DARPA) Photonic Wavelength And Spatial Signal Processing program (PWASSSP).
IR quantum well interferometer imaging spectromete↗