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Aksaev, E. E., Gershenzon, E. M., Gershenson, M. E., Goltsman, G. N., Semenov, A. D., & Sergeev, A. V. (1989). Prospects for using high-temperature superconductors to create electron bolometers. Pisma v Zhurnal Tekhnicheskoi Fiziki, 15(14), 88–93.
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Gershenzon, E. M., Gershenson, M. E., Goltsman, G. N., Karasik, B. S., Lyulkin, A. M., & Semenov, A. D. (1989). Fast-response superconducting electron bolometer. Pisma v Zhurnal Tekhnicheskoi Fiziki, 15(3), 88–92.
Abstract: The general design, operation, and performance characteristics of fast-response electronic bolometers using a thin superconducting Nb film on a leucosapphire substrate are briefly reviewed. The volt-watt sensitivity of the bolometrs is 2,000-200,000 V/W, the operating temperature is 1.6 K, and the time constant is 4-4.5 ns.
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Gershenzon, E. M., Gershenson, M. E., Goltsman, G. N., Lyulkin, A. M., Semenov, A. D., & Sergeev, A. V. (1989). Limiting characteristics of fast-response superconducting bolometers. Zhurnal Tekhnicheskoi Fiziki, 59(2), 11–120.
Abstract: Теоретически и экспериментально исследовано физическое ограничение быстродействия сверхпроводящего болометра. Показано, что минимальная постоянная времени реализуется в условиях электронного разогрева и определяется процессом неупругого электрон-фонон-ного взаимодействия. Сформулированы требования к конструкции «электронного болометра» для достижения предельной чувствительности. Проведено сравнение характеристик электронного болометра и обычных болометров различных типов.
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Voevodin, E. I., Gershenzon, E. M., Goltsman, G. N., Ptitsina, N. G., & Chulkova, G. M. (1988). Capture of free holes by charged acceptors in uniaxially deformed Ge. Fizika i Tekhnika Poluprovodnikov, 22(3), 540–543.
Abstract: Цель настоящей работы — исследование кинетики примесной фотопроводимости p-Ge при сильном одноосном сжатии в широком диапазоне изменения интенсивности примесного подсвета, создающего свободные дырки, и определение сечения каскадного захвата дырок на мелкие заряженные акцепторы в условиях преобладания электрон-фононного механизма потерь энергии.
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Gershenzon, Y. M., Goltsman, G. N., Yelantyev, A. I., Petrova, Y. B., Ptitsina, N. G., & Filatov, V. S. (1987). Lecture demonstrations of properties of superconductors and liquid helium. USSR Rept Phys. Math. JPRS UPM, 24(7), 51.
Abstract: New demonstrations for low temperature physics courses are described. Two transparent Dewar vacuum flasks fitting one inside the other with the external flask for nitrogen and the internal flask for helium are used. The helium temperature can be regulated in the 4.2 to 1.6 K range and the effects of reducing helium to the superfluid state at 2.17 K can be shown: boiling abruptly stops and superfluid flow appears. In order to show the electric and magnetic characteristics of superconductivity, a superconducting NbTi solenoid containing nonsuperconducting wire and germanium and superconducting Nb materials with different critical temperatures is placed in the helium refrigerant vessel. The fall of the resistance at the critical temperatures can be shown. In order to show magnetic field and superconductive current flow properties a shunt of superconductive material is connected in parallel to the coil and is enclosed in a teflon container with a heater which can vary its temperature. When it is heated and not superconductive, magnetic field effects can be demonstrated and when it is unheated and superconducting a continuous current can be demonstrated.
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Gershenzon, E. M., Goltsman, G. N., Multanovskii, V. V., & Ptitsina, N. G. (1982). Kinetics of submillimeter impurity and exciton photoconduction in Ge. Optics and Spectroscopy, 52(4), 454–455.
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Gershenzon, E. M., Goltsman, G. N., & Ptitsyna, N. G. (1974). Investigation of excited donor states in GaAs. Sov. Phys. Semicond., 7(10), 1248–1250.
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Baeva, E. M., Titova, N. A., Veyrat, L., Sacépé, B., Semenov, A. V., Goltsman, G. N., et al. (2021). Thermal relaxation in metal films limited by diffuson lattice excitations of amorphous substrates. Phys. Rev. Applied, 15(5), 054014.
Abstract: We examine the role of a silicon-based amorphous insulating substrate in the thermal relaxation in thin NbN, InOx, and Au/Ni films at temperatures above 5 K. The samples studied consist of metal bridges on an amorphous insulating layer lying on or suspended above a crystalline substrate. Noise thermometry is used to measure the electron temperature Te of the films as a function of Joule power per unit area P2D. In all samples, we observe a P2D∝Tne dependence, with exponent n≃2, which is inconsistent with both electron-phonon coupling and Kapitza thermal resistance. In suspended samples, the functional dependence of P2D(Te) on the length of the amorphous insulating layer is consistent with the linear temperature dependence of the thermal conductivity, which is related to lattice excitations (diffusons) for a phonon mean free path shorter than the dominant phonon wavelength. Our findings are important for understanding the operation of devices embedded in amorphous dielectrics.
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Neroev, V. V., Iomdina, E. N., Khandzhyan, A. T., Khodzhabekyan, N. V., Sengaeva, M. D., Ivanova, A. V., et al. (2021). Experimental study of the effect of corneal hydration and its biomechanical properties on the results of photorefractive keratectomy. Vestn. Oftalmol., 137(3), 68–75.
Abstract: Water content in the cornea may affect the outcome of its excimer laser ablation, especially in presbyopic patients with myopic refraction. This hypothesis can be tested by scanning the cornea in the terahertz (THz) range to determine its hydration level.
Purpose: To study the effect of hydration of the cornea determined by non-contact THz scanning and its biomechanical parameters on the results of photorefractive keratectomy (PRK) in an experiment.
Material and methods: PRK was performed using the Nidek EC-5000 QUEST excimer laser on 8 rabbit eyes. Corneal hydration was evaluated by determining the reflection coefficient (RC) in the THz electromagnetic radiation range before PRK, after 3-5 days, and after 1, 2, 3, and 4 months. Clinical examination included autorefractometry, assessment of corneal thickness and other anatomical and optical parameters of the anterior eye segment (Galilei G6, Ziemer Ophthalmic Systems AG 6.0.2, Switzerland), measurement of corneal hysteresis (CH) and corneal resistance factor (CRF) using the Ocular Response Analyzer (ORA; Reichert, USA), as well as tear production (Schirmer test).
Results: The initial water content in the cornea has a significant effect on the thickness of the removed layer, i.e. on the PRK effect, with correlation coefficient of Rs= -0.976 (p<0.01). The correlation between CH and the ablation depth is less pronounced (Rs=0.643), and CRF had no correlation with it (Rs= -0.089). Biomechanical indicators of the cornea depend on its hydration: changes in CH and CRF after excimer laser ablation qualitatively coincide with changes in RC, the correlation coefficient between RC and the initial value of CH is R= -0.619 (moderate negative correlation).
Conclusion: THz scanning is an effective non-contact technology for monitoring corneal hydration level. The mismatch of the hypoeffect of keratorefractive excimer laser intervention planned for patients with presbyopia with the actual outcome can be caused by individual decrease in the initial water content in the cornea.
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Semenov, A. V., Devyatov, I. A., Korneev, A. A., Smirnov, K. V., Goltsman, G. N., & Melnikov, A. P. (2012). Derivation of expression for thermodynamic potential of “dirty” superconductor. Rus. J. Radio Electron., (4).
Abstract: We derive a formula for thermodynamic potential of dirty superconductor which express it via isotropic quasiclassical Green functions of Usadel theory. Our result allows unify description of dynamic processes and fluctuations in superconducting nano-electronic devices.
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Pernice, W., Schuck, C., Minaeva, O., Li, M., Goltsman, G. N., Sergienko, A. V., et al. (2012). High speed and high efficiency travelling wave single-photon detectors embedded in nanophotonic circuits (Vol. 1108.5299). arXiv:1108.5299v2 [physics.optics].
Abstract: Ultrafast, high quantum efficiency single photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. High photon detection efficiency is essential for scalable measurement-based quantum computation, quantum key distribution, and loophole-free Bell experiments. However, imperfect modal matching and finite photon absorption rates have usually limited the maximum attainable detection efficiency of single photon detectors. Here we demonstrate a superconducting nanowire detector atop nanophotonic waveguides which allows us to drastically increase the absorption length for incoming photons. When operating the detectors close to the critical current we achieve high on-chip single photon detection efficiency up to 91% at telecom wavelengths, with uncertainty dictated by the variation of the waveguide photon flux. We also observe remarkably low dark count rates without significant compromise of detection efficiency. Furthermore, our detectors are fully embedded in a scalable silicon photonic circuit and provide ultrashort timing jitter of 18ps. Exploiting this high temporal resolution we demonstrate ballistic photon transport in silicon ring resonators. The direct implementation of such a detector with high quantum efficiency, high detection speed and low jitter time on chip overcomes a major barrier in integrated quantum photonics.
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Baeva, E. M., Titova, N. A., Veyrat, L., Sacépé, B., Semenov, A. V., Goltsman, G. N., et al. (2021). Thermal relaxation in metal films bottlenecked by diffuson lattice excitations of amorphous substrates. arXiv:2101.07071v1 [cond-mat.mtrl-sci].
Abstract: Here we examine the role of the amorphous insulating substrate in the thermal relaxation in thin NbN, InOx, and Au/Ni films at temperatures above 5 K. The studied samples are made up of metal bridges on an amorphous insulating layer lying on or suspended above a crystalline substrate. Noise thermometry was used to measure the electron temperature Te of the films as a function of Joule power per unit of area P2D. In all samples, we observe the dependence P2D∝Tne with the exponent n≃2, which is inconsistent with both electron-phonon coupling and Kapitza thermal resistance. In suspended samples, the functional dependence of P2D(Te) on the length of the amorphous insulating layer is consistent with the linear T-dependence of the thermal conductivity, which is related to lattice excitations (diffusons) for the phonon mean free path smaller than the dominant phonon wavelength. Our findings are important for understanding the operation of devices embedded in amorphous dielectrics.
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Saveskul, N. A., Titova, N. A., Baeva, E. M., Semenov, A. V., Lubenchenko, A. V., Saha, S., et al. (2019). Superconductivity behavior in epitaxial TiN films points at surface magnetic disorder. 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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Korneeva, Y. P., Vodolazov, D. Y., Semenov, A. V., Florya, I. N., Simonov, N., Baeva, E., et al. (2018). Optical single photon detection in micron-scaled NbN bridges. arXiv:1802.02881v1 [cond-mat.supr-con].
Abstract: We demonstrate experimentally that single photon detection can be achieved in micron-wide NbN bridges, with widths ranging from 0.53 μm to 5.15 μm and for photon-wavelengths from 408 nm to 1550 nm. The microbridges are biased with a dc current close to the experimental critical current, which is estimated to be about 50 % of the theoretically expected depairing current. These results offer an alternative to the standard superconducting single-photon detectors (SSPDs), based on nanometer scale nanowires implemented in a long meandering structure. The results are consistent with improved theoretical modelling based on the theory of non-equilibrium superconductivity including the vortex-assisted mechanism of initial dissipation.
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Sidorova, M. V., Kozorezov, A. G., Semenov, A. V., Korneev, A. A., Chulkova, G. M., Korneeva, Y. P., et al. (2018). Non-bolometric bottleneck in electron-phonon relaxation in ultra-thin WSi film. arXiv:1607.07321v4 [physics.ins-det].
Abstract: We developed the model of the internal phonon bottleneck to describe the energy exchange between the acoustically soft ultrathin metal film and acoustically rigid substrate. Discriminating phonons in the film into two groups, escaping and nonescaping, we show that electrons and nonescaping phonons may form a unified subsystem, which is cooled down only due to interactions with escaping phonons, either due to direct phonon conversion or indirect sequential interaction with an electronic system. Using an amplitude-modulated absorption of the sub-THz radiation technique, we studied electron-phonon relaxation in ultrathin disordered films of tungsten silicide. We found an experimental proof of the internal phonon bottleneck. The experiment and simulation based on the proposed model agree well, resulting in tau{e-ph} = 140-190 ps at TC = 3.4 K, supporting the results of earlier measurements by independent techniques.
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