Semiconductor photon counter with nanosecond gating capability

Single photon avalanche diodes (SPADs) based on various semiconductors have been developed at the Czech Technical University in Prague during the last 20 years. Much attention has been also paid to development of high-speed active quenching circuits for these detectors. Recently, we have performed a series of experiments to characterize our silicon-based photon counters and their capability of operation in a gated mode with the gate duration of single nanoseconds and the detector sensitivity rise time of hundreds of picoseconds. This performance has been achieved by optimizing the active quenching circuit and its components. The fast gating is needed in cases, when the photons of interest are generated short time after a strong optical signal, which cannot be suppressed in optical domain. The time dependence of detection sensitivity, detection delay and timing resolution within the nanosecond gates has been measured.