The device physics of parallel-wire superconducting nanowire single photon detectors is based on a cascade process. Using nano-optical techniques and a parallel wire device with spatially-separate pixels we explicitly demonstrate the single- and multi-photon triggering regimes. We develop a model for describing efficiency of a detector operating in the arm-trigger regime. We investigate the timing response of the detector when illuminating a single pixel and two pixels. We see a change in the active area of the detector between the two regimes and find the two-pixel trigger regime to have a faster timing response than the one-pixel regime.
@article{arxiv.1402.2879,
title = {Nano-optical observation of cascade switching in a parallel superconducting nanowire single photon detector},
author = {Robert M. Heath and Michael G. Tanner and Alessandro Casaburi and Mark G. Webster and Lara San Emeterio Alvarez and Zoe H. Barber and Richard J. Warburton and Robert H. Hadfield},
journal= {arXiv preprint arXiv:1402.2879},
year = {2014}
}