Sidorova, M. V., Divochiy, A. V., Vakhtomin, Y. B., & Smirnov, K. V. (2015). Ultrafast superconducting single-photon detector with a reduced active area coupled to a tapered lensed single-mode fiber. J. Nanophoton., 9(1), 093051.
Abstract: This paper presents an ultrafast niobium nitride (NbN) superconducting single-photon detector (SSPD) with an active area of 3×3 μm2 that offers better timing performance metrics than the previous SSPD with an active area of 7×7 μm2. The improved SSPD demonstrates a record timing jitter (<25 ps), an ultrashort recovery time (<2 ns), an extremely low dark count rate, and a high detection efficiency in a wide spectral range from visible part to near infrared. The record parameters were obtained due to the development of a new technique providing effective optical coupling between a detector with a reduced active area and a standard single-mode telecommunication fiber. The advantages of the new approach are experimentally confirmed by taking electro-optical measurements.
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Zhang, J., Slysz, W., Verevkin, A., Okunev, O., Chulkova, G., Korneev, A., et al. (2003). Response time characterization of NbN superconducting single-photon detectors. IEEE Trans. Appl. Supercond., 13(2), 180–183.
Abstract: We report our time-resolved measurements of NbN-based superconducting single-photon detectors. The structures are meander-type, 10-nm thick, and 200-nm wide stripes and were operated at 4.2 K. We have shown that the NbN devices can count single-photon pulses with below 100-ps time resolution. The response signal pulse width was about 150 ps, and the system jitter was measured to be 35 ps.
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Angeluts, A. A., Bezotosnyi, V. V., Cheshev, E. A., Goltsman, G. N., Finkel, M. I., Seliverstov, S. V., et al. (2014). Compact 1.64 THz source based on a dual-wavelength diode end-pumped Nd:YLF laser with a nearly semiconfocal cavity. Laser Phys. Lett., 11(1), 015004 (1 to 4).
Abstract: We describe a compact dual-wavelength (1.047 and 1.053 μm) diode end-pumped Q-switched Nd:YLE laser source which has a number of applications in demand. In order to achieve its dual-wavelength operation it is suggested for the first time to use essentially nonmonotonous dependences of the threshold pump powers at these wavelengths on the cavity length in the region of the cavity semiconfocal configuration under a radius of the pump beam smaller than the radius of the zero Gaussian mode. Here we demonstrate one of the most interesting applications for this laser: difference frequency generation in a GaSe crystal at a frequency of 1.64 THz. A superconducting hot-electron bolometer is used to detect the THz power generated and to measure its pulse characteristics.
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Shcheslavskiy, V., Morozov, P., Divochiy, A., Vakhtomin, Y., Smirnov, K., & Becker, W. (2016). Ultrafast time measurements by time-correlated single photon counting coupled with superconducting single photon detector. Rev. Sci. Instrum., 87, 053117 (1 to 5).
Abstract: Time resolution is one of the main characteristics of the single photon detectors besides quantum efficiency and dark count rate. We demonstrate here an ultrafast time-correlated single photon counting (TCSPC) setup consisting of a newly developed single photon counting board SPC-150NX and a superconducting NbN single photon detector with a sensitive area of 7 × 7 μm. The combination delivers a record instrument response function with a full width at half maximum of 17.8 ps and system quantum efficiency ~5% at wavelength of 1560 nm. A calculation of the root mean square value of the timing jitter for channels with counts more than 1% of the peak value yielded about 7.6 ps. The setup has also good timing stability of the detector–TCSPC board.
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Tret'yakov, I. V., Kaurova, N. S., Voronov, B. M., Anfert'ev, V. A., Revin, L. S., Vaks, V. L., et al. (2016). The influence of the diffusion cooling on the noise band of the superconductor NbN hot-electron bolometer operating in the terahertz range. Tech. Phys. Lett., 42(6), 563–566.
Abstract: Results of an experimental study of the noise temperature (Tn) and noise bandwidth (NBW) of the superconductor NbN hot-electron bolometer (HEB) mixer as a function of its temperature (Tb) are presented. It was determined that the NBW of the mixer is significantly wider at temperatures close to the critical ones (Tc) than are values measured at 4.2 K. The NBW of the mixer measured at the heterodyne frequency of 2.5 THz at temperature Tb close to Tc was ~13 GHz, as compared with 6 GHz at Tb = 4.2 K. This experiment clearly demonstrates the limitation of the thermal flow from the NbN bridge at Tb â‰<aa> Tc for mixers manufactured by the in situ technique. This limitation is close in its nature to the Andreev reflection on the superconductor/ metal boundary. In this case, the noise temperature of the studied mixer increased from 1100 to 3800 K.
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Shcherbatenko, M., Tretyakov, I., Lobanov, Y., Maslennikov, S. N., Kaurova, N., Finkel, M., et al. (2016). Nonequilibrium interpretation of DC properties of NbN superconducting hot electron bolometers. Appl. Phys. Lett., 109(13), 132602.
Abstract: We present a physically consistent interpretation of the dc electrical properties of niobiumnitride (NbN)-based superconducting hot-electron bolometer mixers, using concepts of nonequilibrium superconductivity. Through this, we clarify what physical information can be extracted from the resistive transition and the dc current-voltage characteristics, measured at suitably chosen temperatures, and relevant for device characterization and optimization. We point out that the intrinsic spatial variation of the electronic properties of disordered superconductors, such as NbN, leads to a variation from device to device.
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Anosov, A. A., Nemchenko, O. Y., Less, Y. A., Kazanskii, A. S., & Mansfel'd, A. D. (2015). Possibilities of acoustic thermometry for controlling targeted drug delivery. Acoust. Phys., 61(4), 488–493.
Abstract: Model acoustic thermometry experiments were conducted during heating of an aqueous liposome suspension. Heating was done to achieve the liposome phase transition temperature. At the moment of the phase transition, the thermal acoustic signal achieved a maximum and decreased, despite continued heating. During subsequent cooling of the suspension, when lipids again passed through the phase transition point, the thermal acoustic signal again increased, despite a reduction in temperature. This effect is related to an increase in ultrasound absorption by the liposome suspension at the moment of the lipid phase transition. The result shows that acoustic thermography can be used to control targeted delivery of drugs mixed in thermally sensitive liposomes, the integrity of which is violated during heating to the phase transition temperature.
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Anosov, A. A., Barabanenkov, Y. N., Kazanskii, A. S., Less, Y. A., & Sharakshane, A. S. (2009). The inverse problem of acoustothermography with correlation reception of thermal acoustic radiation. Acoust. Phys., 55(1), 114–119.
Abstract: For the one-dimensional inverse problem of acoustothermography with correlation reception of thermal acoustic radiation, an integral equation is presented and experimentally verified. A method of solving the inverse problem is proposed. The method is based on combining the correlation functions of thermal acoustic radiation that were obtained for different distances between the receivers.
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Samsonova, A., Zolotov, P., Baeva, E., Lomakin, A., Titova, N., Kardakova, A., et al. (2021). Signatures of surface magnetic disorder in thin niobium films. IEEE Trans. Appl. Supercond., , 1.
Abstract: We present our studies on the evolution of the normal and superconducting properties with thickness of thin Nb films with a low level of non-magnetic disorder (kFl 150 for the thickest film in the set). The analysis of the superconducting behavior points to the presence of magnetic moments, hidden in the native oxide on the surface of Nb films. Using the Abrikosov-Gorkov theory, we obtain the density of surface magnetic moments of 1013 cm-2, which is in agreement with the previously reported data for Nb films.
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Matyushkin, Y., Kaurova, N., Voronov, B., Goltsman, G., & Fedorov, G. (2020). On chip carbon nanotube tunneling spectroscopy. Fullerenes, Nanotubes and Carbon Nanostructures, 28(1), 50–53.
Abstract: We report an experimental study of the band structure of individual carbon nanotubes (SCNTs) based on investigation of the tunneling density of states, i.e. tunneling spectroscopy. A common approach to this task is to use a scanning tunneling microscope (STM). However, this approach has a number of drawbacks, to overcome which, we propose another method – tunneling spectroscopy of SCNTs on a chip using a tunneling contact. This method is simpler, cheaper and technologically advanced than the STM. Fabrication of a tunnel contact can be easily integrated into any technological route, therefore, a tunnel contact can be used, for example, as an additional tool in characterizing any devices based on individual CNTs. In this paper we demonstrate a simple technological procedure that results in fabrication of good-quality tunneling contacts to carbon nanotubes.
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Słysz, W., Węgrzecki, M., Bar, J., Grabiec, P., Gol'tsman, G. N., Verevkin, A., et al. (2005). NbN superconducting single-photon detector coupled with a communication fiber. Elektronika : konstrukcje, technologie, zastosowania, 46(6), 51–52.
Abstract: We present novel superconducting single-photon detectors (SSPDs), based on ultrathin NbN films, designed for fiber-based quantum communications (lambda = 1.3 žm and 1.55 žm). For fiber-based operation, our SSPDs contain a special micromechanical construction integrated with the NbN structure, which enables efficient and mechanically very stabile fiber coupling. The detectors combine GHz counting rate, high quantum efficiency and very low level of dark counts. At 1.3 – 1.55 žm wavelength range our detector exhibits a quantum efficiency up to 10%.
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Goltsman, G., Korneev, A., Izbenko, V., Smirnov, K., Kouminov, P., Voronov, B., et al. (2004). Nano-structured superconducting single-photon detectors. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 520(1-3), 527–529.
Abstract: NbN detectors, formed into meander-type, 10×10-μm2 area structures, based on ultrathin (down to 3.5-nm thickness) and nanometer-width (down to below 100 nm) NbN films are capable of efficiently detecting and counting single photons from the ultraviolet to near-infrared optical wavelength range. Our best devices exhibit QE >15% in the visible range and ∼10% in the 1.3–1.5-μm infrared telecommunication window. The noise equivalent power (NEP) ranges from ∼10−17 W/Hz1/2 at 1.5 μm radiation to ∼10−19 W/Hz1/2 at 0.56 μm, and the dark counts are over two orders of magnitude lower than in any semiconducting competitors. The intrinsic response time is estimated to be <30 ps. Such ultrafast detector response enables a very high, GHz-rate real-time counting of single photons. Already established applications of NbN photon counters are non-invasive testing and debugging of VLSI Si CMOS circuits and quantum communications.
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Семенов, А. В., Корнеев, А. А., Лобанов, Ю. В., Корнеева, Ю. П., Рябчун, С. А., Лаврова, О. С., et al. (2012). Поляризация электромагнитной волны вблизи фокуса зеркала и системы зеркал в субтерагерцовом диапазоне частот. Современные проблемы науки и образования, (2).
Abstract: Рассмотрено влияние оптической системы телескопа на поляризацию принимаемого электромагнитного сигнала. Описано изменение поляризации луча при отражении от произвольно ориентированной поверхности зеркала. Учтены искажения поляризации, обусловленные как отклонением лучей от первоначального направления, так и различием в коэффициентах отражения для разных поляризаций в случае неидеального отражения. В рамках метода Френеля получены оценочные формулы, дающие отношение амплитуд поля с исходной поляризацией и с поляризацией, перпендикулярной исходной, вблизи фокальной точки оптической системы. Формулы выведены для нескольких практически важных случаев, в том числе для параболического зеркала и системы двух зеркал. Оценена верхняя граница поляризационных искажений в пределах кружка Эйри. Полученные оценки согласуются с результатами численного расчёта для двухзеркального радиотелескопа субтерагерцового диапазона.
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Казаков, А. Ю., Селиверстов, С. В., Дивочий, А. В., Смирнов, К. В., Финкель, М. И., & Вахтомин, Ю. Б. (2012). Возможность применения сверхпроводниковых материалов в качестве отражающего покрытия зеркала телескопа, предназначенного для наблюдений анизотропии реликтового излучения. Преподаватель ХХI век, (3), 221–224.
Abstract: В статье исследуется возможность использования сверхпроводящего материала в качестве отражающего слоя зеркала субмиллиметрового телескопа, охлажденного до криогенных температур и предназначенного для наблюдений реликтового излучения. Для нескольких сверхпроводниковых материалов вычислен диапазон частот, в котором флуктуации теплового излучения покрытия меньше флуктуаций источника. Показана перспективность применения покрытия из Nb3Ge.
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Семенов, А. В., Корнеев, А. А., Лобанов, Ю. В., Корнеева, Ю. П., Рябчун, С. А., Третьяков, И. В., et al. (2012). Оценка поляризационных искажений, вносимых оптической системой радиотелескопа миллиметрового диапазона. Преподаватель ХХI век, (4), 230–236.
Abstract: В статье рассмотрена поляризация электромагнитного поля вблизи фокальной точки телескопической системы. Оценена верхняя граница поляризационных искажений, вносимых отражающими поверхностями, в том числе с учетом неидеальности отражения.
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