The solar spectral response of a Schottky-barrier infrared detector (PtSi) is compared to a photovoltaic detector (InSb) of comparable average over the region of interest. The effect of sunlight on a Schottky-barrier detector is found to be even more pronounced than that of a photovoltaic detector of equivalent sensitivity. To reduce this exaggerated effect, a spectral model has been developed for the selection of the optimum filter for use on a PtSi focal-plane array. The model makes it possible to reduce the effect of solar irradiance while not significantly impacting the performance of the detector against a thermal target. The spectral ratio of solar irradiance to a 290-K target for a Schottky-barrier detector is discussed. The solar-to-target contrast ratio is plotted against the integrated 3-5-micron spectral sensitivity to help the user select an optimum cut-off wavelength.

Date Published: 1 October 1990
PDF: 9 pages
Proc. SPIE 1309, Infrared Imaging Systems: Design, Analysis, Modeling, and Testing, (1 October 1990);

Published in SPIE Proceedings Vol. 1309:
Infrared Imaging Systems: Design, Analysis, Modeling, and Testing