Single-Photon Detection by a Dirty Current-Carrying Superconducting Strip Based on the Kinetic-Equation Approach

Despite the prevalence of superconducting nanowire single-photon detectors (SNSPDs) in quantum information processing, optics, and plasmonics, their modeling is based on phenomenological assumptions. This study presents a theory of single-photon detection by a superconducting strip with impurities, based on the dynamics of the electron and phonon distributions. Depending on the strip's material parameters and width, either a hot belt or hot spot forms, and for the latter single-photon detection is possible even in a wide strip at high current, pointing toward even faster devices.