Superconducting nanowire single-photon detectors at a wavelength of 940 nm

TL;DR

This paper presents a superconducting nanowire single-photon detector operating at 940 nm with high efficiency, low dark counts, and fast recovery, suitable for quantum optics applications.

Contribution

Development of a fiber-coupled superconducting nanowire detector with optimized design achieving 60% efficiency at 940 nm.

Findings

Achieved 60% detection efficiency at 940 nm

Dark count rate of 10 Hz

Recovery time less than 12 ns

Abstract

We develop single-photon detectors comprising single-mode fiber-coupled superconducting nanowires, with high system detection efficiencies at a wavelength of 940 nm. The detector comprises a 6.5-nm-thick, 110-nm-wide NbN nanowire meander fabricated onto a Si substrate with a distributed Bragg reflector for enhancing the optical absorptance. We demonstrate that, via the design of a low filling factor (1/3) and active area ({\Phi} = 10 {\mu}m), the system reaches a detection efficiency of ~60% with a dark count rate of 10 Hz, a recovery time <12 ns, and a timing jitter of ~50 ps.