Active Quenching of Superconducting Nanowire Single Photon Detectors

TL;DR

This paper investigates active quenching in superconducting nanowire single photon detectors, predicting and demonstrating significant improvements in performance metrics such as slew rate, peak voltage, count rate, dark count rate, and timing jitter over passive quenching methods.

Contribution

It introduces an active quenching approach for superconducting nanowire detectors, showing theoretical advantages and experimental improvements over traditional passive quenching techniques.

Findings

Order of magnitude increase in slew rate and peak voltage with active quenching

Improved count rates, dark count rates, and timing jitter experimentally

Active quenching removes the need for large shunt resistors

Abstract

Superconducting nanowire single photon detectors are typically biased using a constant current source and shunted in a conductance which is over an order of magnitude larger than the peak normal domain conductance of the detector. While this design choice is required to ensure quenching of the normal domain, the use of a small load resistor limits the pulse amplitude, rising-edge slew rate, and recovery time of the detector. Here, we explore the possibility of actively quenching the normal domain, thereby removing the need to shunt the detector in a small resistance. We first consider the theoretical performance of an actively quenched superconducting nanowire single photon detector and, in comparison to a passively quenched device, we predict roughly an order of magnitude improvement in the slew rate and peak voltage achieved in this configuration. The experimental performance of actively and passively quenched superconducting nanowire single photon detectors are then compared. It is shown that, in comparison to a passively quenched device, the actively quenched detectors simultaneously exhibited improved count rates, dark count rates, and timing jitter.