Probability of the resistive state formation caused by absorption of a single-photon in current-carrying superconducting nano-strips

TL;DR

This study investigates how single-photon absorption can induce a resistive state in superconducting nano-strips, revealing energy-dependent effects that could enhance single-photon detector technology.

Contribution

It provides experimental evidence and analysis of photon-induced resistive state formation in superconducting nano-strips, highlighting spectral cut-offs and energy dependence.

Findings

Resistive state formation probability has a spectral cut-off.

Threshold photon energy decreases with bias current.

Relaxation depends on photon energy, enabling energy resolution.

Abstract

We have studied supercurrent-assisted formation of the resistive state in nano-structured Nb and NbN superconducting films after absorption of a single photon. In amorphous narrow NbN strips the probability of the resistive state formation has a pronounced spectral cut-off. The corresponding threshold photon energy decreases with the bias current. Analysis of the experimental data in the framework of the generalized hot-spot model suggests that the quantum yield for near-infrared photons increases faster than the photon nergy. Relaxation of the resistive state depends on the photon energy making the phenomenon feasible for the development of energy resolving single-photon detectors.