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Proceedings Paper

Thermal infrared-imaging spectrometry with room-temperature optics
Author(s): Clayton C. LaBaw
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Paper Abstract

Conventional approaches to spectroscopy at thermal infrared (IR) wavelengths have involved either cooling of the spectrometer to reduce background radiation in the waveband of interest, or the provision for a cold optical chopper, or both. These methods always required rigorous baffling, and often, relay optics to preclude the viewing of warm surrounds by the detectors, leading to increased cost, complexity, mass and power. A technique has been devised wherein energy at only the wavelength to be measured is imaged onto a detector column. This can provide radiance signal-to-(background) noise ratios > 300 when viewing the Earth in emitted thermal infrared while allowing the optics and the spectrometer to remain at local ambient temperature. Shuttering or chopping of the optical signal is not required with this scheme. A newly developed variable spectral filter is placed in proximity to the detector array to accomplish the necessary background radiation rejection. The theory leading to the development of this filter is described, and a discussion of the application to real optics/detector combinations is provided. A `proof-of-concept' instrument, the Thermal InfraRed Imaging Spectrometer has been built to demonstrate the practibility of the concepts described above. This unit and plans for developmental testing along with proposed areas of improvement are discussed.

Paper Details

Date Published: 15 July 1993
PDF: 13 pages
Proc. SPIE 1874, Infrared and Millimeter-Wave Engineering, (15 July 1993); doi: 10.1117/12.148060
Show Author Affiliations
Clayton C. LaBaw, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 1874:
Infrared and Millimeter-Wave Engineering
Harold T. Buscher, Editor(s)

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