Miniature Low-Light SWIR Camera

To enable small drones to navigate by natural nighttime skyglow, Voxtel is developing an ultra-low-leakage, 9-m-pitch, 1080p-format InGaAs photodiode array for compact, lightweight low-light (LL) short-wavelength infrared (SWIR) imaging. In a Phase II effort, the detectors cutoff wavelength will be adjusted to maximize its uncooled signal-to-noise ratio under illumination from the night sky, trading off greater overlap with the SWIR skyglow spectrum in favor of lower dark current. The uncooled detector will be demonstrated using an existing progressive-scan readout integrated circuit (ROIC). The ROIC has low read noise (approximately 9 e-), which is a requirement for LL imaging. The LL focal plane array (FPA) will be integrated with camera electronics and a custom wide-angle gradient-index (GRIN) lens that collapses a multi-element camera lens into a more compact, lightweight optic. Following characterization of the FPA and the LL imaging with the lightweight GRIN lens in Phase II, the vision systems dynamic range and functionality can be broadened in an enhancement by parting the optimized detector array and pixel circuits high-conversion-gain amplifiers with emerging fine-pixel-pitch digital field-programmable imaging array (FPIA) ROIC designs capable of 24-bit dynamic range and on-chip image processing.