Manova NN, Smirnov EO, Korneeva YP, Korneev AA, Goltsman GN. Superconducting photon counter for nanophotonics applications. In: J. Phys.: Conf. Ser. Vol 1410.; 2019. 012147 (1 to 5).
Abstract: We develop large area superconducting single-photon detector SSPD with a micron-wide strip suitable for free-space coupling or packaging with multi-mode optical fibres. The detector sensitive area is 20 μm in diameter. In near infrared (1330 nm wavelength) our SSPD exhibits above 30% detection efficiency with low dark counts and 45 ps timing jitter.
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Saveskul NA, Titova NA, Baeva EM, Semenov AV, Lubenchenko AV, Saha S, et al. Superconductivity behavior in epitaxial TiN films points at surface magnetic disorder [Internet].; 2019 [cited 2024 Jul 4].arXiv:1903.05009v3 [cond-mat.mtrl-sci]
Abstract: We analyze the evolution of the normal and superconducting electronic properties in epitaxial TiN films, characterized by high Ioffe-Regel parameter values, as a function of the film thickness. As the film thickness decreases, we observe an increase of in the residual resistivity, which becomes dominated by diffusive surface scattering for d≤20nm. At the same time, a substantial thickness-dependent reduction of the superconducting critical temperature is observed compared to the bulk TiN value. In such a high quality material films, this effect can be explained by a weak magnetic disorder residing in the surface layer with a characteristic magnetic defect density of ∼1012cm−2. Our results suggest that surface magnetic disorder is generally present in oxidized TiN films.
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Saveskul NA, Titova NA, Baeva EM, Semenov AV, Lubenchenko AV, Saha S, et al. Superconductivity behavior in epitaxial TiN films points to surface magnetic disorder. Phys Rev Applied. 2019;12(5):054001.
Abstract: We analyze the evolution of the normal and superconducting properties of epitaxial TiN films, characterized by high Ioffe-Regel parameter values, as a function of the film thickness. As the film thickness decreases, we observe an increase of the residual resistivity, that becomes dominated by diffusive surface scattering for d≤20nm. At the same time, a substantial thickness-dependent reduction of the superconducting critical temperature is observed compared to the bulk TiN value. In such high-quality material films, this effect can be explained by a weak magnetic disorder residing in the surface layer with a characteristic magnetic defect density of approximately 1012cm−2. Our results suggest that surface magnetic disorder is generally present in oxidized TiN films.
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Rasulova GK, Pentin IV, Goltsman GN. Terahertz emission from a weakly-coupled GaAs/AlGaAs superlattice biased into three different modes of current self-oscillations. AIP Advances. 2019;9(10):105220.
Abstract: Radio-frequency modulated terahertz (THz) emission power from weakly-coupled GaAs/AlGaAs superlattice (SL) has been increased by parallel connection of several SL mesas. Each SL mesa is a self-oscillator with its own oscillation frequency and mode. In coupled non-identical SL mesas biased at different voltages within the hysteresis loop the chaotic, quasiperiodic and frequency-locked modes of self-oscillations of current arise. THz emission was detected when three connected in parallel SL mesas were biased into the frequency-locked and quasiperiodic modes of self-oscillations of current, while in the chaotic mode of those it falls to the noise level.
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Elezov M, Scherbatenko M, Sych D, Goltsman G, Arakelyan S, Evlyukhin A, et al. Towards the fiber-optic Kennedy quantum receiver. In: EPJ Web Conf. Vol 220.; 2019. 03011 (1 to 2).
Abstract: We consider practical aspects of using standard fiber-optic elements and superconducting nanowire single-photon detectors for the development of a practical quantum receiver based on the Kennedy scheme. Our receiver allows to discriminate two phase-modulated coherent states of light at a wavelength of 1.5 microns in continuous mode with bit rate 200 Kbit/s and error rate about two times below the standard quantum limit.
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