Light Absorption Optimization for Superconducting Nanowire Single-Photon Detector Based on PSO

Improving the absorption ability of incident photons is an important issue for the design of the superconducting nanowire single-photon detector (SNSPD). In this paper, a SNSPD loaded with Au reflector is optimized to realize desired light absorption properties. First, the transfer matrix method (TMM) is used to model the light response of a layered SNSPD structure. Then, a particle swarm optimization algorithm (PSO) with linearly varying inertia weight is introduced to find out the optimal device structure, including the material type and thickness of the layers. For the incident photons in the near-infrared band, the optimized SNSPD can achieve both single-peak high absorption at a single wavelength point and effective absorption in a wide wavelength range, specifically, >99% absorption at 1310nm and >70% in the wavelength regime of 1100nm -1700nm.