Large-format blocked-impurity-band focal plane arrays for long-wavelength infrared astronomy

Abstract

Large-format, very-long-wavelength infrared (VLWIR) hybrid focal plane arrays (HFPAs) based on doped-silicon blocked-impurity-band (BIB) detectors have been developed and demonstrated for a variety of astronomy applications. An HFPA consists of a BIB detector array interfaced via indium column interconnects to a matching cryogenic signal processor/multiplexer. Arsenic-doped silicon (Si:As) BIB detector arrays with useful photon response out to nearly 30 micrometers are the most fully developed embodiment of this technology. HFPAs with Si:As BIB arrays have been optimized for low, moderate, and high infrared backgrounds in 128 X 128-pixel formats, and a high-flux 256 X 256-pixel version is under development. For high-flux applications, both the detector array and multiplexer are optimized to handle incident flux densities > 10 16 photons cm -2 s -1 , providing high spatial uniformity, high pixel operability, and background-limited performance down to low frequencies ( 40 micrometers have also been demonstrated, primarily for use at low and moderate backgrounds. BIB technology offers producible, low-cost, high-performance focal planes for astronomy in the VLWIR.