High Speed Room Temperature Single Photon Counters

Detecting light at the single photon level is a fundamental measurement function that is useful in a wide variety of applications, including such diverse fields as quantum communications, laser ranging, and biological spectroscopy. Avalanche photodiode based single-photon detectors are convenient solid-state devices that do not require cryogenic cooling. We will build avalanche photodiode based single-photon-detection systems that make use of advanced gating techniques to improve their count rate. The single-photon detectors will be used in quantum measurement, such as entanglement distribution, and lidar applications. We will also use nonlinear frequency conversion to enable improved single-photon detectors in the telecom-wavelength bands around 1.3 and 1.5 microns.