Silicon-Based, Hardened, Extended Response Photodetector Array (SHERPA)

ABSTRACT: Agiltron will develop the Silicon-Based, Hardened, Extended Response Photodetector Array (SHERPA) for Air Force space-based applications. The SHERPA sensor contains an array of fully-CMOS compatible silicon nanowire phototransistors whose unique nanoscale architecture enables extended spectral response spanning the UV, visible, and SWIR wavebands, colossal internal gain at biases on the order of 1 V, near-unity quantum efficiency, low dark current comparable to silicon PIN photodiodes, and greater radiation and laser hardness compared to standard CMOS or CCD imagers. The nanowire pixel array will be integrated with a radiation hardening by design (RHBD) CMOS readout integrated circuitry (ROIC) to realize a robust silicon-based sensor that can meet the functional requirements for Air Force space-based applications. BENEFIT: The proposed low-SWAP, robust SHERPA sensor is designed for rapid detection of visible and SWIR lasers for space-based surveillance and reconnaissance applications. It is also ideal for numerous terrestrial military applications requiring low-light level sensitivity, such as target acquisition and designation, reconnaissance, range safety, forward observation, and surveillance. Because the SHERPA sensor is silicon-based, it will have significantly lower cost than other SWIR technologies, particularly InGaAs and HgCdTe, making it attractive for diverse applications such as chemical and biological agent detection, environmental sensing, non-destructive testing, covert illumination, range gated imaging, free space communications, hyperspectral imaging, and wavefront sensing, tracking, and ranging for missile threat warning systems. The SHERPA sensor will be critical in supporting airborne and ground-based military operations in modern warfare arenas, either as standalone sensors or in combination with MWIR and LWIR sensors.