Phys.org April 13, 2021
Researchers at NIST have demonstrated a method that allows a high-efficiency single-photon-avalanche diode (SPAD) with a thick absorption region to count single photons at rates significantly higher than previously demonstrated. They applied large (>30 V) AC bias gates to the SPAD at 1 GHz and detected minute avalanches by means of radio frequency interferometry. They measured a reduction by a factor of ≈500 in the average charge per avalanche when compared to operation in its traditional active-quenching module and a relative increase in >19% in detection efficiency at 850 nm. The reduction in charge strongly suppresses self-heating effects in the diode that can degrade performance at high avalanche rates. They showed that the single-photon detection system maintains high efficiency at count rates exceeding 108 s−1…read more. Open Access TECHNICAL ARTICLEÂ
The electron and hole are accelerated by the applied bias voltage. Credit: Sean Kelley/NIST