Multifunctional Superconducting Nanowire Quantum Sensors

TL;DR

This paper demonstrates that amorphous superconducting nanowire single photon detectors (SNSPDs) maintain high performance in strong magnetic fields and can be used as multifunctional quantum sensors for magnetometry and thermometry by adjusting bias currents.

Contribution

It introduces a robust SNSPD design that operates effectively in high magnetic fields and can function as a multifunctional sensor for temperature and magnetic field measurements.

Findings

SNSPDs operate with negligible dark counts up to ±6 T magnetic fields.

SNSPDs can be used as magnetometers with sensitivity better than 100 μT/√Hz.

SNSPDs can function as thermometers with sensitivity of 20 μK/√Hz at 1 K.

Abstract

Superconducting nanowire single photon detectors (SNSPDs) offer high-quantum-efficiency and low-dark-count-rate single photon detection. In a growing number of cases, large magnetic fields are being incorporated into quantum microscopes, nanophotonic devices, and sensors for nuclear and high-energy physics that rely on SNSPDs, but superconducting devices generally operate poorly in large magnetic fields. Here, we demonstrate robust performance of amorphous SNSPDs in magnetic fields of up to $\pm 6$ T with a negligible dark count rate and unchanged quantum efficiency at typical bias currents. Critically, we also show that in the electrothermal oscillation regime, the SNSPD can be used as a magnetometer with sensitivity of better than 100 $\mathrm{\mu T/\sqrt{Hz}}$ and as a thermometer with sensitivity of 20 $\mathrm{\mu K/\sqrt{Hz}}$ at 1 K. Thus, a single photon detector integrated into a quantum device can be used as a multifunctional quantum sensor capable of describing the temperature and magnetic field on-chip simply by varying the bias current to change the operating modality from single photon detection to thermometry or magnetometry.