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Корнеев, А. А., Окунев, О. В., Чулкова, Г. М., Смирнов, К. В., Милостная, И. И., Минаева, О. В., et al. (2015). Спонтанные и фотоиндуцированные резистивные состояния в узких сверхпроводящих NbN полосках. МПГУ.
Abstract: Монография посвящена актуальной проблеме современной фотоники: разработке высокочувствительных и быстродействующих сверхпроводниковых однофотонных детекторов на основе тонкой пленки NbN. В работе исследуются неравновесные процессы, протекающие в тонкой сверхпроводящей пленке после поглощения инфракрасного фотона и приводящие к возникновению резистивного состояния. На этих процессах основан механизм фотоотклика исследуемого в работе однофотонного детектора. В частности, исследуются зависимости квантовой эффективности и скорости темнового счета от геометрических параметров детектора: толщины пленки, ширины полоски, а также от величины транспортного тока детектора. Монография предназначена для студентов старших курсов, аспирантов и начинающих исследователей, работающих в области сверхпроводниковой наноэлектроники и радиофизики.
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Лесс, Ю. А., & Кирсанов, Ю. А. (2015). Былое и думы. Посвящение эпохе Н. Н. Малова, Е. М. Гершензона, В. С. Эткина.
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Ferrari, S., Kahl, O., Kovalyuk, V., Goltsman, G. N., Korneev, A., & Pernice, W. H. P. (2015). Waveguide-integrated single- and multi-photon detection at telecom wavelengths using superconducting nanowires. Appl. Phys. Lett., 106(15), 151101 (1 to 5).
Abstract: We investigate single- and multi-photon detection regimes of superconducting nanowire detectors embedded in silicon nitride nanophotonic circuits. At near-infrared wavelengths, simultaneous detection of up to three photons is observed for 120 nm wide nanowires biased far from the critical current, while narrow nanowires below 100 nm provide efficient single photon detection. A theoretical model is proposed to determine the different detection regimes and to calculate the corresponding internal quantum efficiency. The predicted saturation of the internal quantum efficiency in the single photon regime agrees well with plateau behavior observed at high bias currents.
W. H. P. Pernice acknowledges support by the DFG Grant Nos. PE 1832/1-1 and PE 1832/1-2 and the Helmholtz society through Grant No. HIRG-0005. The Ph.D. education of O. Kahl is embedded in the Karlsruhe School of Optics and Photonics (KSOP). G. N. Goltsman acknowledges support by Russian Federation President Grant HШ-1918.2014.2 and Ministry of Education and Science of the Russian Federation Contract No.: RFMEFI58614X0007. A. Korneev acknowledges support by Statement Task No. 3.1846.2014/k. V. Kovalyuk acknowledges support by Statement Task No. 2327. We also acknowledge support by the Deutsche Forschungsgemeinschaft (DFG) and the State of Baden-Württemberg through the DFG-Center for Functional Nanostructures (CFN) within subproject A6.4. We thank S. Kühn and S. Diewald for the help with device fabrication as well as B. Voronov and A. Shishkin for help with NbN thin film deposition and A. Semenov for helpful discussion about the detection mechanism of nanowire SSPD's.
The authors declare no competing financial interests.
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Kahl, O., Ferrari, S., Kovalyuk, V., Goltsman, G. N., Korneev, A., & Pernice, W. H. P. (2015). Waveguide integrated superconducting single-photon detectors with high internal quantum efficiency at telecom wavelengths. Sci. Rep., 5, 10941 (1 to 11).
Abstract: Superconducting nanowire single-photon detectors (SNSPDs) provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, compatibility with an integrated optical platform is a crucial requirement for applications in emerging quantum photonic technologies. Here we present efficiencies close to unity at 1550nm wavelength. This allows for the SNSPDs to be operated at bias currents far below the critical current where unwanted dark count events reach milli-Hz levels while on-chip detection efficiencies above 70% are maintained. The measured dark count rates correspond to noiseequivalent powers in the 10–19W/Hz–1/2 range and the timing jitter is as low as 35ps. Our detectors are fully scalable and interface directly with waveguide-based optical platforms.
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Vodolazov, D. Y., Korneeva, Y. P., Semenov, A. V., Korneev, A. A., & Goltsman, G. N. (2015). Vortex-assisted mechanism of photon counting in a superconducting nanowire single-photon detector revealed by external magnetic field. Phys. Rev. B, 92(10), 104503 (1 to 9).
Abstract: We use an external magnetic field to probe the detection mechanism of a superconducting nanowire single-photon detector. We argue that the hot belt model (which assumes partial suppression of the superconducting order parameter Δ across the whole width of the superconducting nanowire after absorption of the photon) does not explain observed weak-field dependence of the photon count rate (PCR) for photons with λ=450nm and noticeable decrease of PCR (with increasing the magnetic field) in a range of the currents for photons with wavelengths λ=450–1200nm. Found experimental results for all studied wavelengths can be explained by the vortex hot spot model (which assumes partial suppression of Δ in the area with size smaller than the width of the nanowire) if one takes into account nucleation and entrance of the vortices to the photon induced hot spot and their pinning by the hot spot with relatively large size and strongly suppressed Δ.
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