Single-photon detectors (SPDs) are nonlinear transducers that respond to the absorption of one or more photons with an electrical signal1. SPDs at near infrared wavelengths with high system detection efficiency (> 90%), low dark count rate (< 1 counts per second, cps), low timing jitter (<100 ps), and short reset time (< 100 ns) would enable milestone experiments in a variety of fields such as quantum physics, astronomy, communications, biology, and chemistry. Although some of the existing approaches to single-photon detection fulfill one or two of the above specifications, to date no detector has met all of the specifications simultaneously. Here we report on a fiber-coupled single-photon-detection system employing superconducting nanowire single photon detectors (SNSPDs) that closely approaches the ideal performance of SPDs. Our detector system has a system detection efficiency (SDE), including fiber coupling loss, greater than 90% in the wavelength range λ = 1520 1610 nm; device dark count rate (measured with the device shielded from room-temperature blackbody radiation) of ~ 0.01 cps; timing jitter of ~ 150 ps FWHM; and reset time of 40 ns. Our SNSPDs outperform conventional SNSPDs by using a new material, amorphous tungsten silicide (WSi). WSi nanowires allow more degrees of freedom in optimizing the optical coupling to the detectors, are more robust to constrictions, and have a lower dark count rate than conventional devices. We expect fiber coupled WSi SNSPDs to find application in (1) fundamental tests of quantum mechanics, especially loophole-free Bell inequality measurements with photons ; (2) quantum information processing and communication; (3) time-tagged single photon counting; and (4) environmental monitoring.
Pub Type: Journals