Multispectral and low-filling-factor superconducting nanowire single photon detector with high absorption efficiency

We propose a superconducting nanowire single photon detector (SNSPD) that can work efficiently at two target wavelengths and has a significant improvement in the counting rate due to the low-filling-factor nanowires in the silicon slots and the silver reflector. Numerical simulations show that the absorption efficiency can be over 90% at a single wavelength, whether the incident light wavelength is 1550 nm or 1064 nm, and over 80% when the SNSPD is designed to work at both wavelengths. In addition, the reset time is about 24% of the conventional SNSPDs. Our work presents a design for fabricating faster, larger-area, and multispectral SNSPDs with a high efficiency, which can be applied in applications such as quantum optics communication and multiwavelength sensing.