Megapixel Longwave Infrared SLS FPAs for High Spatial Resolution Earth Observing Missions

Earth observing missions like NASA's LANDSAT Data Continuity Mission - Thermal Infrared Sensor (LDCM-TIRS) require greater spatial resolution of the earth than the ~ 100m provided by the current instrument. Improving resolution to the desired ~ 30m requires increasing the number of pixels on target from the current 640x3 to ~ 2048x3. The TIRS instrument contains 640x512 longwave infrared quantum well infrared photodetector focal plane arrays (LWIR QWIP FPAs) jointly developed by NASA/GSFC and QmagiQ. QmagiQ proposes to achieve the higher pixel resolution while simultaneously improving quantum efficiency and operating temperature by using antimony-based strained layer superlattice (SLS) detectors. A key challenge is dealing with the effects of reducing pixel pitch from 25 microns down to ~ 10 microns, viz. optical fill-factor, optical crosstalk, processing difficulties, pixel operability, etc. As a stepping stone in Phase I, we developed and delivered an SLS FPA with 1280x1024 format on 12 micron pitch that achieved record performance, viz. > 40% quantum efficiency and dark current half of MCT Rule07 for FPAs with cutoff wavelength > 11 microns. In Phase II, we will increase FPA format to 2048x2048 and push cutoff wavelength to 12-13 microns while still hitting desired quantum efficiency and operating temperature targets in consultation with NASA/GSFC. Several FPAs will be delivered to NASA for evaluation. More »