Photon-Number-Resolving Detector Based on Superconducting Serial Nanowires

A novel photon-number-resolving detector based on serially connected superconducting nanowires is presented. The serial nanowire detector (SND) uses spatial multiplexing on a subwavelength scale, the same as the parallel nanowire detector (PND), to provide an output signal proportional to the number of incident photons and avoids the problem of leakage current that the PND suffers from, thus allowing both high quantum efficiency and large number of resolvable photons. Electrothermal simulation results of the SND exhibit a better linearity than that of the PND, and the influence of some important design parameters on the detector's performance is investigated. In addition, noise analysis is done in order to estimate the upper limit of the element number of the SND. Finally, a modified segmental current supply scheme is proposed to overcome the problem of constrictions.