High-efficiency WSi superconducting nanowire single-photon detectors operating at 2.5 K

TL;DR

This study demonstrates high-efficiency WSi superconducting nanowire single-photon detectors operating at 2.5 K, achieving near-saturation detection efficiency and highlighting the advantages of amorphous WSi for close-to-TC operation.

Contribution

It shows that WSi SNSPDs can operate efficiently at temperatures close to their transition temperature, with potential for improved performance using cryogenic amplifiers.

Findings

Detection efficiency saturates at 78% at 2.5 K

Jitter is 191 ps and limited by readout noise

Operation near TC is a unique property of amorphous WSi

Abstract

We investigate the operation of WSi superconducting nanowire single-photon detectors (SNSPDs) at 2.5 K, a temperature which is ~ 70 % of the superconducting transition temperature (TC) of 3.4 K. We demonstrate saturation of the system detection efficiency at 78 +- 2 % with a jitter of 191 ps. We find that the jitter at 2.5 K is limited by the noise of the readout, and can be improved through the use of cryogenic amplifiers. Operation of SNSPDs with high efficiency at temperatures very close to TC appears to be a unique property of amorphous WSi.