Kozorezov, A. G., Lambert, C., Marsili, F., Stevens, M. J., Verma, V. B., Stern, J. A., et al. (2015). Quasiparticle recombination in hotspots in superconducting current-carrying nanowires. Phys. Rev. B, 92(6).
Abstract: We describe a kinetic model of recombination of non-equilibrium quasiparticles generated by single photon absorption in superconducting current-carrying nanowires. The model is developed to interpret two-photon detection experiments in which a single photon does not possess sufficient energy for breaking superconductivity at a fixed low bias current. We show that quasiparticle self- recombination in relaxing hotspot dominates diffusion expansion effects and explains the observed strong bias current, wavelength and temperature dependencies of hotspot relaxation in tungsten silicide superconducting nanowire single-photon detectors.
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Marsili, F., Verma, V. B., Stern, J. A., Harrington, S., Lita, A. E., Gerrits, T., et al. (2013). Detecting single infrared photons with 93% system efficiency. Nat. Photon., 7(3), 210–214.
Abstract: Single-photon detectors1 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 fields2, 3, 4, 5, 6. Although some of the existing approaches to single-photon detection fulfil one or two of the above specifications1, 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 detectors7 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 λ = 1,520–1,610 nm, with a device dark count rate (measured with the device shielded from any background radiation) of ~1 c.p.s., timing jitter of ~150 ps full-width at half-maximum (FWHM) and reset time of 40 ns.
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