IR- and visible- light single photon detection in superconducting $MgB_{2}$ nanowires

TL;DR

This paper demonstrates that superconducting MgB₂ nanowires can serve as fast, efficient single-photon detectors for visible and infrared light, outperforming traditional NbN detectors in speed with low dark counts.

Contribution

It provides the first experimental evidence of MgB₂ nanowires functioning as single-photon detectors with high speed and efficiency for both visible and infrared photons.

Findings

MgB₂ nanowires detect visible and IR photons at high speed.

Dark count rate is less than 10 cps.

MgB₂ detectors outperform NbN SNSPDs in response speed.

Abstract

State-of-the-art Superconducting Nanowire Single Photon Detectors based on low-Tc materials reach 100% quantum efficiency. However, the response time is limited to >1-10 ns. Recently, it has been shown that due to a much lower kinetic inductance, a 100 ps response rate can be achieved in 120 $\mu$m-long $MgB_{2}$ nanowires. In this work, we demonstrate experimentally that such $MgB_{2}$ nanowires function as single-photon detectors for both visible ($\lambda$= 630 nm) and infrared ($\lambda$= 1550 nm) photons when biased close to the critical current, with a dark count rate of <10 cps. $MgB_{2}$ photodetectors over-perform NbN SNSPDs in speed by at least an order of magnitude for similar nanowire lengths. Such photodetectors offer a platform for single-photon detectors with a long thought-after combination of a large detector area and a response rate of up to 10 GHz with a single readout line.