Full Numerical Simulations of Dynamical Response in Superconducting Single-Photon Detectors

We numerically study transport phenomena in a superconducting detector. Our approach is to simulate the three-dimensional time-dependent Ginzburg-Landau equation coupled with heat-diffusion and Maxwell equations. The simulation shows dynamical transition to a resistive state when an incident particle has energy higher than superconducting transition temperature. We show temporal behaviors of a superconducting gap function, depending on the incident energy scale. Furthermore, we discuss the applicability of our method to a superconducting single-photon detector. Focusing on the effects of coupling with heat sink and magnitude of quasi-particle fluctuations, we show a significant decrease of detector´s threshold energy.