Timing performance of 30-nm-wide superconducting nanowire avalanche photodetectors

TL;DR

This study measures the timing jitter of 30-nm-wide superconducting nanowire avalanche photodetectors, revealing sub-35 ps jitter near the switching current and explaining IRF shifts with electrothermal simulations.

Contribution

It provides the first detailed analysis of timing performance of ultra-narrow superconducting nanowire avalanche photodetectors and models IRF shifts with electrothermal simulations.

Findings

SNAPs show sub 35 ps jitter near switching current

IRF becomes wider and shifts at lower bias currents

Electrothermal model explains IRF time-shift

Abstract

We investigated the timing jitter of superconducting nanowire avalanche photodetectors (SNAPs, also referred to as cascade switching superconducting single photon detectors) based on 30-nm-wide nanowires. At bias currents (IB) near the switching current, SNAPs showed sub 35 ps FWHM Gaussian jitter similar to standard 100 nm wide superconducting nanowire single-photon detectors. At lower values of IB, the instrument response function (IRF) of the detectors became wider, more asymmetric, and shifted to longer time delays. We could reproduce the experimentally observed IRF time-shift in simulations based on an electrothermal model, and explain the effect with a simple physical picture.