In this paper, we present a stable single-photon detection method based on Si-avalanche photodiode(Si-APD) operating in Geiger mode with a large temperature variation range. By accurate temperature sensing and direct current(DC) bias voltage compensation, the single-photon detector can work stably in Geiger mode from-40 °C to 35 °C with an almost constant avalanche gain. It provides a solution for single-photon detection at outdoor operation in all-weather conditions.
We demonstrate a photon counting laser ranging experiment with a four-channel single-photon detector(SPD). The multi-channel SPD improve the counting rate more than 4×10~7 cps, which makes possible for the distance measurement performed even in daylight. However, the time-correlated single-photon counting(TCSPC) technique cannot distill the signal easily while the fast moving targets are submersed in the strong background. We propose a dynamic TCSPC method for fast moving targets measurement by varying coincidence window in real time. In the experiment, we prove that targets with velocity of 5 km/s can be detected according to the method, while the echo rate is 20% with the background counts of more than 1.2×10~7 cps.
We report a time-of-flight photon-counting imaging system in conjunction with a single-photon detector mounted with a fiber optic taper, which equivalently enlarges the active area of the single-photon detector by 100 times. The field of view of the imaging system is extended from ±0.57° to ±7° by using the fiber optic taper to collect the scattered photons. Since only a single avalanche photodiode is used, the noise level of the system is maintained at a low level. We demonstrate the scanning of the targets at a stand-off distance of 28 m with a centimeter depth resolution.
