Simulation of superconducting single photon detector coupled with metal-insulator-metal circular grating

Metal-insulator-metal (MIM) circular grating structure has been introduced to couple with superconducting nanowire single-photon detector (SNSPD) to enhance its response. According to our numerical simulation results, the coupling efficiency at 1.55μm can be enhanced by MIM circular grating and improving the response of SNSPD obviously. About 19.5 times of enhancement in response can be obtained with proper structure parameters.