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Verevkin, A., Zhang, J., Pearlman, A., Slysz, W., Sobolewski, R., Korneev, A., et al. (2004). Ultimate sensitivity of superconducting single-photon detectors in the visible to infrared range.
Abstract: We present our quantum efficiency (QE) and noise equivalent power (NEP) measurements of the meandertype ultrathin NbN superconducting single-photon detector in the visible to infrared radiation range. The nanostructured devices with 3.5-nm film thickness demonstrate QE up to~ 10% at 1.3–1.55 µm wavelength, and up to 20% in the entire visible range. The detectors are sensitive to infrared radiation with the wavelengths down to~ 10 µm. NEP of about 2× 10-18 W/Hz1/2 was obtained at 1.3 µm wavelength. Such high sensitivity together with GHz-range counting speed, make NbN photon counters very promising for efficient, ultrafast quantum communications and another applications. We discuss the origin of dark counts in our devices and their ultimate sensitivity in terms of the resistive fluctuations in our superconducting nanostructured devices.
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Kuznetsov, K. A., Kornienko, V. V., Vakhtomin, Y. B., Pentin, I. V., Smirnov, K. V., & Kitaeva, G. K. (2018). Generation and detection of optical-terahertz biphotons via spontaneous parametric downconversion. In Proc. ICLO (303).
Abstract: We study spontaneous parametric downconversion (SPDC) in the strongly non-degenerate regime when the idler wave hits the terahertz range. By using the hot-electron bolometer, for the first time the SPDC-generated idler-wave photons were directly detected in the terahertz frequency range. Spectrum of corresponding signal photons was measured using standard technique by the CCD camera. Possible applications of correlated optical-terahertz biphotons are discussed.
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Zolotov, P. I., Vakhtomin, Y. B., Divochiy, A. V., Seleznev, V. A., & Smirnov, K. V. (2016). Technology development of resonator-based structures for efficiency increasing of NBN detectors of IR single photons. Proc. 5th Int. Conf. Photonics and Information Optics, , 115–116.
Abstract: This paper presents a technology of fabrication of NbN superconductive single- photon detectors, using resonator structures. The main results are related to optimization of the process of NbN sputtering over substrate with metallic mirrors and SiO 2 /Si 3 N 4 layers /4 thick. Investigation of the quantum efficiency of fabricated devices at 1.6 K on 1.55 μm showed triple-magnified value compared to standard Si/NbN structures.
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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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Smirnov, K., Vachtomin, Y., Divochiy, A., Antipov, A., & Goltsman, G. (2015). The limitation of noise equivalent power by background radiation for infrared superconducting single photon detectors coupled to standard single mode optical fibers. Rus. J. Radio Electron., (5).
Abstract: We investigated the minimum level of the dark count rates and noise equivalent power of superconducting single photon detectors coupled to standard single mode optical fibers. We found that background radiation limits the minimum level of the dark count rates. We also proposed the effective method for reducing background radiation out of the required spectral range of the detector. Measured noise equivalent power of detector reaches 8.9×10-19 W×Hz1/2 at a wavelength of 1.55 μm and quantum efficiency 35%.
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