The technology developed on this SBIR will create improved thermopile readout to meet broadband infrared data collection. Thermal detectors (such as thermopiles), while typically less sensitive than quantum detectors, are useful when the combination of long wavelength signals and relatively high temperature operation (100-200K) makes LWIR and VLWIR quantum detectors unsuitable. Thermal detectors are also appropriate in applications requiring flat spectral response over a broad wavelength range. Thermopile area (2-D) arrays are required in future thermal instruments supporting infrared earth and planetary observing missions. A potential NASA application is a thermopile area array imaging capability with radiation tolerance to support missions to Jupiter.
Thermopile detectors require no electrical bias, and generate a voltage output that is proportional to the input radiation signal. They are also typically uncooled and are insensitive to substrate temperature variations, making temperature stabilization unnecessary. They are highly linear, which combined with their insensitivity to substrate temperature, broadband spectral sensitivity and low 1/f noise; make them ideal for accurate radiometry. A two-dimensional thermopile array built over CMOS readout circuitry in the substrate will allow large format staring imaging arrays that will compete and perhaps offer better performance than bolometer-based staring FPA imagers for radiometric imaging applications. Broadband IR area array sensors with filters allow spectral imaging.
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