Infrared spectroradiometer design based on an acousto-optic tunable filter

Lyle H. Taylor; Dennis R. Suhre; Steve A. Wutzke; Phil L. Ulerich; Gary D. Baldwin; Mark T. Meyers; Jefferson E. Odhner

doi:10.1117/12.210889

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12 June 1995 Infrared spectroradiometer design based on an acousto-optic tunable filter

Lyle H. Taylor; Dennis R. Suhre; Steve A. Wutzke; Phil L. Ulerich; Gary D. Baldwin; Mark T. Meyers; Jefferson E. Odhner

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Proceedings Volume 2480, Imaging Spectrometry; (1995) https://doi.org/10.1117/12.210889
Event: SPIE's 1995 Symposium on OE/Aerospace Sensing and Dual Use Photonics, 1995, Orlando, FL, United States

Abstract

An advanced infrared imaging spectroradiometer for hot targets (100 to 1500 C) has been designed to give real-time spectrally resolved images in the 2-5 micrometers band and to measure irradiances with high accuracy. A tripod-mounted off-axis afocal telescope with a 2.5 degree diagonal field of view directs the input radiation through a Tl₃AsSe₃ acousto-optic tunable filter (AOTF). The AOTF deflects away from the main beam a narrow spectral bandwidth beam with its central wavelength determined by the acoustic frequency of the AOTF. The AOTF is electronically controlled and can change the wavelength of the deflected beam within approximately 25 microsecond(s) to any other wavelength. The deflected beam is focused onto an 128 X 128 InSb focal plane array which has a frame rate electronically adjustable from 1 to 217 frame/s. With this versatility: 1) key wavelength discriminators of potential targets can be rapidly accessed, 2) the signal-to-noise ration can be improved by increasing the integration time for point targets, and 3) detector saturation can be avoided by reducing the integration time and AOTF diffraction efficiency for very hot targets. Calculations indicate that irradiance measurement errors should usually be less than 1% and often less than 0.1%.

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Lyle H. Taylor, Dennis R. Suhre, Steve A. Wutzke, Phil L. Ulerich, Gary D. Baldwin, Mark T. Meyers, and Jefferson E. Odhner "Infrared spectroradiometer design based on an acousto-optic tunable filter", Proc. SPIE 2480, Imaging Spectrometry, (12 June 1995); https://doi.org/10.1117/12.210889

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