Afterpulse correction of silicon single-photon detector for 1064-nm aerosol-lidar

Near-infrared enhanced silicon single-photon avalanche diodes (Si-SPADs) are widely used as detectors for 1064-nm aerosol lidars. However, Si-SPADs suffer from afterpulse miscounts. The superconducting nanowire single-photon detector (SNSPD) exhibits high QE and negligible rate of afterpulse miscounts. We have developed a lidar system that uses a fiber beam splitter (50:50 intensity ratio) which permits the simultaneous quantitative comparison of signal quality obtained with Si-SPAD and with SNSPD. In fact, SNSPD can be used as a reference for 1064-nm aerosol lidars. The experimental results demonstrate that the Si-SPAD exhibits non-negligible afterpulse miscounts, which affect the quantitative detection of aerosol optical properties. The probability density function of the afterpulse miscounts is calculated by measuring the count rates of the afterpulse caused by a hard target. Subsequently, an afterpulse correction algorithm has been developed. The algorithm reduces the error in the backscattering coefficient (β) by about 25% under the experimental conditions.