The influence of the nanowire geometry in SNSPDs

The optimization of the nanowire geometry of superconducting single photon detector is demonstrated in this paper. A typical setting of the detection area, 10 umtimes10 um, is adopted in this experiment. With 4 nm NbN films, the falling time of the response pulse is calculated, which implies the falling time increase a lot for narrow nanowire. At the same time, the falling time also increase a little at high fill factor. At the same time, decreasing the width and increasing the fill factor will degrade the repeating rate of SNSPDs. Considering those, the SNSPDs with larger fill factor will produce high detector efficiency and without increasing the repeating rate.