Universal Response Curve for Nanowire Superconducting Single-Photon Detectors

TL;DR

This paper introduces a universal detection curve for NbN-based superconducting single-photon detectors, revealing a fundamental relationship between bias current, energy, and detection probability through detector tomography.

Contribution

It presents a novel linear combination model for detection probability and employs a sparsity-based tomographic method to analyze multiphoton excitations in SSPDs.

Findings

Detection probability depends on a specific linear combination of bias current and energy.

A universal detection curve applies across various bias currents and input energies.

The model enhances understanding of meander-type SSPDs.

Abstract

Using detector tomography, we investigate the detection mechanism in NbN-based superconducting single photon detectors (SSPDs). We demonstrate that the detection probability uniquely depends on a particular linear combination of bias current and energy, for a large variation of bias currents, input energies and detection probabilities, producing a universal detection curve. We obtain this result by studying multiphoton excitations in a nanodetector with a sparsity-based tomographic method that allows factoring out of the optical absorption. We discuss the implication of our model system for the understanding of meander-type SSPDs.