Elvira, D., Michon, A., Fain, B., Patriarche, G., Beaudoin, G., Robert-Philip, I., et al. (2010). Time-resolved spectroscopy of InAsP/InP(001) quantum dots emitting near 2 μm. Appl. Phys. Lett., 97(13), 131907 (1 to 3).
Abstract: By using superconducting single photon detectors, we perform time-resolved characterization of a small ensemble of InAsP/InP quantum dots grown by metal organic vapor phase epitaxy, emitting at wavelengths between 1.6 and 2.2 μm. We demonstrate that alloying phosphorus with InAs allows to shift the emission wavelength toward higher wavelengths, while keeping the high optical quality of these quantum dots at room temperature, with no decrease in their radiative lifetime. This work was partially supported by Russian Ministry of Science and Education: Federal State Program “Scientific and Educational Cadres of Innovative” state Contract Nos. 02.740.0228, 14.740.11.0343, 14.740.11.0269, and P931, and RFBR Project No. 09-02-12364.
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Glejm, A. V., Anisimov, A. A., Asnis, L. N., Vakhtomin, Y. B., Divochiy, A. V., Egorov, V. I., et al. (2014). Quantum key distribution in an optical fiber at distances of up to 200 km and a bit rate of 180 bit/s. Bulletin of the Russian Academy of Sciences. Physics, 78(3), 171–175.
Abstract: An experimental demonstration of a subcarrier-wave quantum cryptography system with superconducting single-photon detectors (SSPDs) that distributes a secure key in a single-mode fiber at distance of 25 km with a bit rate of 800 kbit/s, a distance of 100 km with a bit rate of 19 kbit/s, and a distance of 200 km with a bit rate of 0.18 kbit/s is described.
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Zolotov, P. I., Semenov, A. V., Divochiy, A. V., Goltsman, G. N., Romanov, N. R., & Klapwijk, T. M. (2021). Dependence of photon detection efficiency on normal-state sheet resistance in marginally superconducting films of NbN. IEEE Trans. Appl. Supercond., 31(5), 1–5.
Abstract: We present an extensive set of data on nanowire-type superconducting single-photon detectors based on niobium-nitride (NbN) to establish the empirical correlation between performance and the normal-state resistance per square. We focus, in particular, on the bias current, compared to the expected depairing current, needed to achieve a near-unity detection efficiency for photon detection. The data are discussed within the context of a model in which the photon energy triggers the movement of vortices i.e. superconducting dissipation, followed by thermal runaway. Since the model is based on the non-equilibrium theory for conventional superconductors deviations may occur, because the efficient regime is found when NbN acts as a marginal superconductor in which long-range phase coherence is frustrated.
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Korneeva, Y. P., Mikhailov, M. Y., Pershin, Y. P., Manova, N. N., Divochiy, A. V., Vakhtomin, Y. B., et al. (2014). Superconducting single-photon detector made of MoSi film. Supercond. Sci. Technol., 27(9), 095012.
Abstract: We fabricated and characterized nanowire superconducting single-photon detectors made of 4 nm thick amorphous Mox Si1−x films. At 1.7 K the best devices exhibit a detection efficiency (DE) up to 18% at 1.2 $\mu {\rm m}$ wavelength of unpolarized light, a characteristic response time of about 6 ns and timing jitter of 120 ps. The DE was studied in wavelength range from 650 nm to 2500 nm. At wavelengths below 1200 nm these detectors reach their maximum DE limited by photon absorption in the thin MoSi film.
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Korneev, A. A., Korneeva, Y. P., Mikhailov, M. Y., Pershin, Y. P., Semenov, A. V., Vodolazov, D. Y., et al. (2015). Characterization of MoSi superconducting single-photon detectors in the magnetic field. IEEE Trans. Appl. Supercond., 25(3), 2200504 (1 to 4).
Abstract: We investigate the response mechanism of nanowire superconducting single-photon detectors (SSPDs) made of amorphous MoxSi1-x. We study the dependence of photon count and dark count rates on bias current in magnetic fields up to 113 mT at 1.7 K temperature. The observed behavior of photon counts is similar to the one recently observed in NbN SSPDs. Our results show that the detecting mechanism of relatively high-energy photons does not involve the vortex penetration from the edges of the film, and on the contrary, the detecting mechanism of low-energy photons probably involves the vortex penetration from the film edges.
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