UMD researchers have developed a single-photon avalanche diode (SPAD) detection system that is so sensitive that it detects photons that arrive at times well before a readout gate is applied, hence increasing the system’s detection duty cycle. This invention by Dr. Alessandro Restelli of the Joint Quantum Institute represents a new mode of operation for SPADs, similar to charge-coupled devices (CCD), in which single-photon signals may be accumulated within the detector and read out some time later. This increases the duration of time during which the detector is sensitive to single-photon signals. This new mode of operation will expand the usefulness of SPADs in the areas of Light Detection and Ranging (LIDAR) and quantum cryptography.
Restelli, along with National Institute of Standards and Technology (NIST) physicists Joshua C. Bienfang and Alan L. Migdall, and California Institute of Technology’s Jet Propulsion Laboratory physicist William H. Farr, developed this photon detector system.