1.5 um SPAD for Ladar Detection

A solid state photodetector will be developed for efficient detection of 1.5 um photons with single photon sensitivity, notably offering operation above 200 K without needing gating. The photodetector will be an avalanche photodiode operated in Geiger modeand fabricated using novel materials and a novel structure that blocks nearly all of the thermally generated noise in absorption region from reaching the gain region and multiplying. Computational simulations of the materials and structure predictthousand-fold greater sensitivity than heretofore possible. Phase I will design, build and test parts of an initial device to prove that the physics underlying the devices will support ladar applications. Phase II will extend the device to an 8 x 8 arrayformat suitable for eye-safe ladar applications. The ultimate sensitivity detection of 1.5 um photons may be important to future LADAR needing to maintain eye safety at multi-Watt laser power, and to a number of commercial applications needing low cost,low power, high speed, and small size, without needing liquid nitrogen temperatures or time-gated operation. Commercial opportunities exist in passive plume imaging, atmospheric particulate sensing, telecommunications instrumentation, quantumcommunications systems exchanging single photons securely at high duty cycle, telescope adaptive optics, and tracking of space vehicle position.