Long-to-Very-Long-Wavelength Infrared Band-Pass Filters for Space Infrared Detectors

This Phase I SBIR proposal requests innovative sensor solutions to improve strategic space sensors. One route of improvement is selective band-pass filtering of radiation before it reaches the detector. Such filtering can improve detection by blocking out-of-band interferences and allowing transmission of the desired spectral components. Filtering can improve a cheaper detector with a broader detection profile into a high performance detector. Filtering can also improve signal-to-noise of a detector by eliminating out-of-band radiation from reaching the detector and causing spurious signal or A/D saturation. Comparable band-pass filters in the mid-infrared are typically thick multilayer dielectrics subject to poor adhesion between layers, thermal mismatch stress, or moisture sensitivity which can lead to destructive delamination. The innovative very-long-wavelength-region band-pass filter design proposed here has high transmission, can tolerate cryogenic temperatures, ionizing radiation and vibration making them launch-capable. The 2mm-thin proposed band-pass filter allows insertion into tight spaces. Lake Shore has demonstrated prototype band-pass filters with center bands from 14 – 25 microns in the infrared spectrum. By using innovative fabrication, it will be possible to extend this range down to the long-wavelength-infrared region. New IR detectors, developed in-tandem with Lake Shore band-pass filters can produce a high-performance solution for MDA applications.