Impedance-matched differential superconducting nanowire detectors

Abstract

Superconducting nanowire single-photon detectors (SNSPDs) are the highest performing photon-counting technology in the near-infrared (NIR). Due to delay-line effects, large area SNSPDs typically trade-off timing resolution and detection efficiency. Here, we introduce a detector design based on transmission line engineering and differential readout for device-level signal conditioning, enabling a high system detection efficiency and a low detector jitter, simultaneously. To make our differential detectors compatible with single-ended time taggers, we also engineer analog differential-to-single-ended readout electronics, with minimal impact on the system timing resolution. Our niobium nitride differential SNSPDs achieve $47.3\%\pm 2.4\%$ system detection efficiency and sub-$10\mathrm{ps}$ system jitter at $775\mathrm{nm}$, while at $1550\mathrm{nm}$ they achieve $71.1\%\pm 3.7\%$ system detection efficiency and $13.1\mathrm{ps}\pm 0.4\mathrm{ps}$ system jitter. These detectors also achieve sub-100 ps timing response at one one-hundredth maximum level, $30.7\mathrm{ps}\pm 0.4\mathrm{ps}$ at $775\mathrm{nm}$ and $47.6\mathrm{ps}\pm 0.4\mathrm{ps}$ at $1550\mathrm{nm}$, enabling time-correlated single-photon counting with high dynamic range response functions. Furthermore, thanks to the differential impedance-matched design, our detectors exhibit delay-line imaging capabilities and photon-number resolution. The properties and high-performance metrics achieved by our system make it a versatile photon-detection solution for many scientific applications.