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

摘要

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 (T_C) of 3.4 K. We demonstrate saturation of the system detection efficiency at 78 ± 2% at a wavelength of 1310 nm, 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 T_C appears to be a unique property of amorphous WSi.