Fractal superconducting nanowires detect infrared single photons with 84% system detection efficiency, 1.02 polarization sensitivity, and 20.8 ps timing resolution

TL;DR

This paper introduces fractal-shaped superconducting nanowire detectors that achieve high efficiency, low polarization dependence, and excellent timing resolution for infrared single-photon detection, advancing quantum photonics applications.

Contribution

The authors design and experimentally demonstrate a novel fractal geometry for SNSPDs that significantly reduces polarization dependence while maintaining high efficiency and timing performance.

Findings

84% system detection efficiency at 1575 nm

Polarization sensitivity of 1.02

Timing jitter of 20.8 ps

Abstract

The near-unity system detection efficiency (SDE) and excellent timing resolution of superconducting nanowire single-photon detectors (SNSPDs), combined with their other merits, have enabled many classical and quantum photonic applications. However, the prevalent design based on meandering nanowires makes SDE dependent on the polarization states of the incident photons; for unpolarized light, the major merit of high SDE would get compromised, which could be detrimental for photon-starved applications. Here, we create SNSPDs with an arced fractal geometry that almost completely eliminates this polarization dependence of the SDE, and we experimentally demonstrate 84$\pm$3$\%$ SDE, 1.02$^{+0.06}_{-0.02}$ polarization sensitivity at the wavelength of 1575 nm, and 20.8 ps timing jitter in a 0.1-W closed-cycle Gifford-McMahon cryocooler, at the base temperature of 2.0 K. This demonstration provides a novel, practical device structure of SNSPDs, allowing for operation in the visible, near-, and mid-infrared spectral ranges, and paves the way for polarization-insensitive single-photon detection with high SDE and high timing resolution