Temperature Dependent Performances of Superconducting Nanowire Single-Photon Detectors in an Ultralow-Temperature Region

TL;DR

This study investigates the performance of superconducting nanowire single-photon detectors at ultralow temperatures, revealing high efficiency and dark count origins, crucial for quantum sensing applications.

Contribution

It provides detailed temperature-dependent performance data of SNSPDs down to 16 mK, highlighting efficiency saturation and dark count sources without using optical cavities.

Findings

Detection efficiency reaches 15% below 1.4 K.

Dark counts persist at 16 mK due to black body radiation.

Efficiency saturation occurs with bias current and temperature.

Abstract

We present the performances of a superconducting nanowire single-photon detector (SNSPD) in an ultralow-temperature region from 16 mK to 4 K. The system detection efficiency of the SNSPD showed saturation in the bias-current and temperature dependences, and reached the considerably high value of 15% for 100 Hz dark count rate below 1.4 K at a wavelength of 1550 nm even without an optical cavity structure. We found that the dark count exists even at 16 mK and black body radiation becomes its dominant origin in the low temperatures for fiber-coupled devices.