Large-Format Linear-Mode Single-Photon-Sensitive Flash LADAR Receiver

The most effective strategy to increase LADAR range performance while minimizing size, weight and power (SWAP) growth is to increase the sensitivity of the detectors used in the receiver. To address this need, a radiation-hard, 256256-format flash-LADAR receiver will be developed based on linear-mode single carrier multiplication (SCM) InGaAs avalanche photodiode (APD) array technology with 85% quantum efficiency, 4x the responsivity, and 1/6th the excess multiplication noise of conventional InGaAs APDs. The innovation is intended to supplant Geiger-mode APD receivers, whose performance is highly variable in cluttered scenes due to the technology"s long dead times, inability to detect more than one photon per dead-time period, and inability to detect pulse amplitude. Contrastingly, the proposed single-photon-sensitive LADAR detector technology can record pulse time of arrival to<100 ps, pulse intensity to 10 bits, and the time of arrival and pulse amplitude of up to three pulse returns per pixel at a 20-kHz frame rates. In Phase I, a SCM-APD ladar receiver will be fabricated and its superior performance documented. The Phase I results will be used in Phase II to fabricate and assemble a low-SWAP 256256 LADAR camera. In Phase II, radiation and lifetime testing will also be performed. BENEFIT: The single-photon-sensitive APD technology is ideal for applications where laser power is limited and high-resolution 3D imaging is needed for enhanced situational awareness or navigation. Promising applications include 3D data for targeting, mission planning, vertical obstruction identification, site survey, atmospheric profiling, autonomous navigation, automotive cruise control and hazard avoidance, wavefront sensing, and adaptive optics.