Detecting single infrared photons with 93% system efficiency

Single-photon detectors(1) at near-infrared wavelengths with high system detection efficiency (>90%), low dark count rate (<1 c.p.s.), low timing jitter (<100 ps) and short reset time (<100 ns) would enable landmark experiments in a variety of fields(2-6). Although some of the existing approaches to single-photon detection fulfil one or two of the above specifications(1), to date, no detector has met all of the specifications simultaneously. Here, we report on a fibre-coupled single-photon detection system that uses superconducting nanowire single-photon detector(7) and closely approaches the ideal performance of single-photon detectors. Our detector system has a system detection efficiency (including optical coupling losses) greater than 90% in the wavelength range lambda = 1,520-1,610 nm, with a device dark count rate (measured with the device shielded from any background radiation) of similar to 1 c.p.s., timing jitter of similar to 150 ps full-width at half-maximum (FWHM) and reset time of 40 ns.