An efficient and polarization sensitive SNSPD with coupled asymmetric SRR-loaded cavity

Highly efficient SNSPD with high polarization sensitivity is useful in the field of quantum communication and optical imaging. Here we propose a SNSPD design in which the superconducting nanowire is embedded in a resonant cavity loaded with a coupled asymmetric split ring resonator (CASRR). The superconducting nanowire is placed in a properly selected position where the electric field is zero for TM illumination and non-zero for TE illumination, as caused by the polarization sensitive response of the CASRR. Through numerical simulations, we have designed a SNSPD whose TE absorption efficiency is 85.5% and the polarization extinction ratio (PER) is 585. Besides, a low filling factor of 0.2 and a large width of 120nm help to reduce the response time of SNSPD and facilitate its fabrication processes. Our numerical simulation based analysis shows the proposed SNSPD has a good tolerance for various fabrication parameters.