Geiger-mode APD single-photon cameras for 3D laser radar imaging
We describe the design and performance of short-wave infrared 3D imaging cameras with focal plane arrays (FPAs) based on Geiger-mode avalanche photodiodes (GmAPDs) with single photon sensitivity for laser radar imaging applications. The FPA pixels incorporate InP/InGaAs(P) GmAPDs for the detection of single photons with high efficiency and low dark count rates. Based on the design of the GmAPD detectors, FPAs have been optimized for source wavelengths near either 1.0 μm or 1.5 μm. We present results and attributes of fully integrated camera sub-systems with 32 × 32 and 128 × 32 formats, which have 100 μm pitch and 50 μm pitch, respectively. We also address the sensitivity of the fundamental GmAPD detectors to radiation exposure, including recent results that correlate detector active region volume to sustainable radiation tolerance levels. For GmAPD detector designs that are compatible with our existing FPA platform, these discrete device results indicate that sensors with our current level of performance can be designed to tolerate radiation exposure of at least 8 krad with acceptable levels of dark count rate elevation.