UV superconducting nanowire single-photon detectors with high efficiency, low noise, and 4 K operating temperature

TL;DR

This paper reports the development of ultraviolet superconducting nanowire single-photon detectors (SNSPDs) with high efficiency, low noise, and operation at 4 K, suitable for various UV photon detection applications.

Contribution

The authors design, fabricate, and characterize UV SNSPDs optimized for wavelengths between 250-370 nm with high efficiency and low dark counts, operating at higher temperatures than typical SNSPDs.

Findings

Achieved 70-80% efficiency in UV detection

Dark count rate of ~0.25 counts/hr for 56 μm detectors

Operates at temperatures up to 4.2 K

Abstract

For photon-counting applications at ultraviolet wavelengths, there are currently no detectors that combine high efficiency (> 50%), sub-nanosecond timing resolution, and sub-Hz dark count rates. Superconducting nanowire single-photon detectors (SNSPDs) have seen success over the past decade for photon-counting applications in the near-infrared, but little work has been done to optimize SNSPDs for wavelengths below 400 nm. Here, we describe the design, fabrication, and characterization of UV SNSPDs operating at wavelengths between 250 and 370 nm. The detectors have active areas up to 56 ${\mu}$m in diameter, 70 - 80% efficiency, timing resolution down to 60 ps FWHM, blindness to visible and infrared photons, and dark count rates of ~ 0.25 counts/hr for a 56 ${\mu}$m diameter pixel. By using the amorphous superconductor MoSi, these UV SNSPDs are also able to operate at temperatures up to 4.2 K. These performance metrics make UV SNSPDs ideal for applications in trapped-ion quantum information processing, lidar studies of the upper atmosphere, UV fluorescent-lifetime imaging microscopy, and photon-starved UV astronomy.