Minimal timing jitter in superconducting nanowire single photon detectors

Abstract

Using two-temperature model coupled with modified time-dependent Ginzburg-Landau equation we calculate the delay time $\tau_d$ in appearance of growing normal domain in the current-biased superconducting strip after absorption of the single photon. We demonstrate that $\tau_d$ depends on the place in the strip where photon is absorbed and monotonically decreases with increasing of the current. We argue, that the variation of $\tau_d$ (timing jitter), connected either with position-dependent response or Fano fluctuations could be as small as the lowest relaxation time of the superconducting order parameter $\sim \hbar/k_BT_c$ ($T_c$ is the critical temperature of the superconductor) when the current approaches the depairing current.