Design of double-layer MoSi superconducting microstrip single-photon detector with a high-light absorption

We report a design of double-layer MoSi superconducting microstrip single-photon detector(SMSPD) at 1550 nm. The proposed structure consists of a top anti-reflection dielectric layer, a optical cavity and a double microstrip layer. We optimize the thickness of the anti-reflection layer to enhance the light absorption through the Finite-Difference Time-Domain(FDTD) method. The simulation result indicates that the optimized device structure has an light absorption rate exceeds 99.9%.This paper provides a new design structure for subsequent high-efficiency SMSPDs.