Simulation of superconducting nanowire single photon detector with phase grating structure

Phase grating structure has the ability to converge light. We have introduced it to couple with superconducting nanowire single photon detector (SNSPD) to enhance its response for light. The effects of the coupling structure parameters on the enhancement have been studied systematically by FDTD method. Our numerical simulation show that the optical density arriving on nanowires of SNSPDs can be enhanced greatly by using SiO₂ phasing grating structure, which can extremely improve the system detector efficiency of SNSPDs. It can improve the efficiency over 45% at wavelength of 404 nm.