Superconducting nanowire single-photon detector

The superconducting nanowire single-photon detector (SNSPD or SSPD) is a type of optical and near-infrared single-photon detector based on a current-biased superconducting nanowire. It was first developed by scientists at Moscow State Pedagogical University and at the University of Rochester in 2001. The first fully operational prototype was demonstrated in 2005 by the National Institute of Standards and Technology (Boulder), and BBN Technologies as part of the DARPA Quantum Network.

As of 2023, a superconducting nanowire single-photon detector is the fastest single-photon detector (SPD) for photon counting. It is a key enabling technology for quantum optics and optical quantum technologies. SNSPDs are available with very high detection efficiency, very low dark count rate and very low timing jitter, compared to other types of single-photon detectors. SNSPDs are covered by International Electrotechnical Commission (IEC) international standards. As of 2023, commercial SNSPD devices are available in multichannel systems in a price range of 100,000 euros.

It was recently discovered that superconducting wires as wide as 1.5 µm can detect single infra-red photons. This is important because optical lithography rather than electron lithography can be used in their construction. This reduces the cost for applications that require large photodetector areas. One application is in dark matter detection experiments, where the target is a scintillating GaAs crystal. GaAs suitably doped with silicon and boron is a luminous cryogenic scintillator that has no apparent afterglow and is available commercially in the form of large, high-quality crystals.