High-efficiency, high-count-rate 2D superconducting nanowire single-photon detector array.

Superconducting nanowire single-photon detectors (SNSPDs) are currently the leading technology for the detection of single-photons in the near-infrared (NIR) and short-wave infrared (SWIR) spectral regions, due to record performance in terms of detection efficiency, low dark count rate, minimal timing jitter, and high maximum count rates. The various design parameters of SNSPDs are often carefully tailored to specific applications, due to challenges in optimizing each performance characteristic without adversely impacting others. Here we demonstrate a practical, self-contained, free-space coupled, 64-pixel SNSPD array system which exhibits high performance of all operational parameters, for use in the strategically important SWIR spectral region. The detector consists of an 8 × 8 array of 27.5 × 27.8 µm pixels on a 30 µm pitch, which leads to a maximum 85% fill factor. At a wavelength of λ = 1550 nm, a uniform average per-pixel photon detection efficiency of > 77.7% was measured and the observed system detection efficiency (SDE) across the entire array was 65%. A full performance characterization is presented, including a dark count rate of 15 cps per pixel, mean full-width-half-maximum (FWHM) jitter of 112 ps per pixel, a 3-dB maximum count rate of 645 Mcps and no evidence of crosstalk at the 0.1% level. This camera system therefore facilitates a variety of picosecond time-resolved measurement-based applications such as biomedical imaging, quantum communications, and long-range single-photon light detection and ranging (LiDAR) and 3D imaging.