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Author Cao, Aiqin; Jiang, L.; Chen, S.H.; Antipov, S.V.; Shi, S.C.
Title IF gain bandwidth of a quasi-optical NbN superconducting HEB mixer Type Conference Article
Year 2007 Publication Proc. International conference on microwave and millimeter wave technology Abbreviated Journal Proc. ICMMT
Volume Issue Pages 1-3
Keywords HEB, mixer, gain bandwidth
Abstract (up) In this paper, the intermediate frequency (IF) gain bandwidth of a quasi-optical NbN superconducting hot-electron bolometer (HEB) mixer is investigated at 500 GHz with an IF system incorporating with a frequency down-converting scheme which is able to sweep the IF signal in a frequency range of 0.3-4 GHz. The IF gain bandwidth of the device is measured to be 1.5 GHz when it is biased at a voltage of the minimum noise temperature, and becomes larger when the bias voltage increases.
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Call Number RPLAB @ lobanovyury @ Serial 575
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Author Polyakova, M. I.; Korneev, A. A.; Semenov, A. V.
Title Comparison single- and double- spot detection efficiencies of SSPD based to MoSi and NbN films Type Conference Article
Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume 1695 Issue Pages 012146 (1 to 3)
Keywords NbN SSPD, SNSPD, MoSi
Abstract (up) In this work, we present results of quantum detector tomography of superconducting single photon detector (SSPD) based on MoSi film, and compare them with previously reported data on NbN. We find that for both materials hot spot interaction length coincides with the strip width, and the dependence of single and double-spot detection efficiencies on bias current are compatible with sufficiently large hot-spot size, approaching the strip width.
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ISSN 1742-6588 ISBN Medium
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Call Number Serial 1787
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Author Loudkov, D.; Tong, C.-Y. E.; Marrone, D. P.; Ryabchun, S.; Paine, S. N.; Blundell, R.
Title Transmission measurements of infrared filters for low-noise terahertz receiver applications Type Conference Article
Year 2005 Publication Proc. 16th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 16th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 354-357
Keywords FTS, Zitex, alkali halide, crystalline quartz, Parylene, polyethylene, IR filters, transmission, THz applications
Abstract (up) Infrared (IR) filters are very important to the efficient operation of cryogenic receivers. Usually, such filters are mounted on the radiation shield of the cryostat to reduce the heat load to the 4 K stage. Insufficient filtering may cause the temperature of the mixing element in a receiver to be excessively warm, leading to degradation in sensitivity. These filters should be effective in blocking the room temperature IR radiation from outside the cryostat, yet should be transparent across the desired signal frequency band. In the Terahertz frequency range, which is close to the infrared, it is difficult to find an inexpensive low- loss material that can provide the required IR blocking capacity. We present transmission measurements, made using a Fourier Transform Spectrometer (FTS), of a number of potential infrared filters between 0.4 and 1.6 THz. The filters tested include the widely-used, Teflon-based, Zitex-A and Zitex-G films, alkali halide based infrared filter, and crystalline quartz coated with Parylene, and polyethylene films.
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Call Number Serial 1473
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Author Darula, Marian; Semenov, Alex D.; Hübers, Heinz-Wilhelm; Schubert, Josef
Title Quasioptical high-Tc superconductor Josephson mixer at terahertz frequencies Type Abstract
Year 2000 Publication Proc. 11th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 11th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 515
Keywords HTS Josephson mixers
Abstract (up) Mixers based on Josephson junctions from conventional superconductor materials have demonstrated excellent performance at subgap frequencies. The advantages of Josephson mixers are low optimal power of the local oscillator and large intermediate frequency bandwidth but their noise temperature increases dramatically at frequencies corresponding to the energy gap of the superconductor, which is typically below 1 THz for widely used materials. The large energy gap of oxide superconductors makes them promising candidates for development of terahertz Josephson mixers. Here we report on experimental study of the quasioptical mixer utilizing bicrystal Josephson junction from high-transition-temperature YBa 2 Cu 3 O 7-δ film. Junctions with a width of 2 µm were fabricated from 100 nm thick laser ablated films on bicrystal MgO substrates and had the and the J C R n product of about 2 mV at 4.2 K. The planar complementary logarithmic spiral antenna incorporated into co-planar waveguide was patterned from 200 nm thick gold film thermally evaporated in situ on top of the YBa 2 Cu 3 O 7-δ film. The mixer chip was clamped to the extended hemispherical silicon lens. Performance of the mixer was investigated at 4.5 K bath temperature. We used FIR laser as a local oscillator at frequencies 0.698 and 2.52 THz. System noise temperature (DSB) was determined from Y-factor measured with 300 K and 77 K loads. At 0.698 THz the lowest noise temperature 1750 K was observed when the mixer was biased with the fixed current to the region in the vicinity of either the first Shapiro step or the critical current. Between these two bias points the noise temperature increased to ≈ 20000 K. As function of the local oscillator power the noise temperature reached the minimum when the critical current was suppressed to the half of its equilibrium value. Power of the local oscillator absorbed by the mixer at optimal operation was of the order 100 nW. The present design of our antenna limits the upper operation frequency to the value of 1.8 THz. Nevertheless, we clearly observed Shapiro steps at the frequency 2.52 THz. Bearing in mind an improved design of the antenna, we estimate the 3000 K DSB noise temperature at this frequency.
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Call Number Serial 1555
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Author Ekström, H.; Karasik, B.; Kollberg, E.; Yngvesson, K. S.
Title Investigation of a superconducting hot electron mixer Type Conference Article
Year 1994 Publication Proc. 5th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 5th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 169-188
Keywords HEB mixers
Abstract (up) Mixing at 20 GHz in niobium superconducting thin film strips in the resistive state is studied. Experiments give evidence that electron-heating is the main cause of the non linear phenomena. The requirements on the mode of operation and on the film parameters for small conversion loss and the possibility of conversion gain are discussed. Measurements indicate a minimum intrinsic conversion loss around 1 dB with a sharp drop for the lowest voltage bias-points, and a DSB mixer noise temperature between 100 and 450 K at 20 GHz. The device output noise temperature at the mixer operating point can be as low as 30-50 K. A simple theory is presented, which is based on the assumption that the small signal resistance is linearly dependent on power. This type of mixer is considered very promising for use in low-noise heterodyne receivers at THz frequencies.
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Call Number Serial 1642
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Author Anosov, A. A.; Nemchenko, O. Yu.; Less, Yu. A.; Kazanskii, A. S.; Mansfel'd, A. D.
Title Possibilities of acoustic thermometry for controlling targeted drug delivery Type Journal Article
Year 2015 Publication Acoust. Phys. Abbreviated Journal
Volume 61 Issue 4 Pages 488-493
Keywords acoustic thermometry, liposome suspension, thermography
Abstract (up) 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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Call Number Serial 1130
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Author Edward Tong, C.-Y.; Loudkov, Denis N.; Paine, Scott N.; Marrone, Dan P.; Blundell, Raymond
Title Vector measurement of the beam pattern of a 1.5 THz superconducting HEB receiver Type Conference Article
Year 2005 Publication Proc. 16th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 16th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 453-456
Keywords NbTiN HEB mixers
Abstract (up) Near-field vector beam pattern of the 1.5 THz superconducting Hot Electron Bolometer (HEB) receiver currently in operation in Northern Chile has been performed in our laboratory. Using an open waveguide probe, we have mapped both the amplitude and phase of the beam emerging from our 1.5 THz HEB receiver package, across a number of planes along the line of propagation of the radio-beam. With an integration time of about 100 ms per point, a signal-to-noise ratio of about 25 dB was achieved for a beam waist of 3.5 mm. These measurements have proved to be invaluable in achieving good alignment between the cryostat housing the HEB mixer and the remainder of the receiver and telescope optics. The accuracy of our beam measurement is estimated to be ±0.2 mm in position and ±5 arc minutes in angular displacement.
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Call Number Serial 1474
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Author Семенов, А. В.; Девятов, И. А.; Третьяков, И. В.; Лобанов, Ю. В.; Ожегов, Р. В.; Петренко, Д. В.; Селиверстов, С. В.; Финкель, М. И.
Title Вывод уравнения типа уравнения гинзбурга-ландау для нанопроволоки вблизи критического магнитного поля Type Journal Article
Year 2011 Publication Журнал радиоэлектроники Abbreviated Journal Ж. радиоэлектроники
Volume 11 Issue Pages 4
Keywords superconductivity; nanowire; Ginzburg-Landau equation
Abstract (up) Nonlinear Ginzburg-Landau equation for dirty supercondicting 1D wire is derived in the limit of high magnetic field.

В пределе больших магнитных полей выведено нелинейное уравнение Гинзбурга-Ландау, описывающее состояние одномерной «грязной» нанопроволоки.
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Call Number RPLAB @ gujma @ Serial 714
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Author Matyushkin, Y.; Danilov, S.; Moskotin, M.; Belosevich, V.; Kaurova, N.; Rybin, M.; Obraztsova, E. D.; Fedorov, G.; Gorbenko, I.; Kachorovskii, V.; Ganichev, S.
Title Helicity-sensitive plasmonic terahertz interferometer Type Journal Article
Year 2020 Publication Nano Lett. Abbreviated Journal Nano Lett.
Volume 20 Issue 10 Pages 7296-7303
Keywords graphene, plasmonic interferometer, radiation helicity, terahertz radiation
Abstract (up) Plasmonic interferometry is a rapidly growing area of research with a huge potential for applications in the terahertz frequency range. In this Letter, we explore a plasmonic interferometer based on graphene field effect transistor connected to specially designed antennas. As a key result, we observe helicity- and phase-sensitive conversion of circularly polarized radiation into dc photovoltage caused by the plasmon-interference mechanism: two plasma waves, excited at the source and drain part of the transistor, interfere inside the channel. The helicity-sensitive phase shift between these waves is achieved by using an asymmetric antenna configuration. The dc signal changes sign with inversion of the helicity. A suggested plasmonic interferometer is capable of measuring the phase difference between two arbitrary phase-shifted optical signals. The observed effect opens a wide avenue for phase-sensitive probing of plasma wave excitations in two-dimensional materials.
Address CENTERA Laboratories, Institute of High Pressure Physics, PAS, 01-142 Warsaw, Poland
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ISSN 1530-6984 ISBN Medium
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Notes PMID:32903004 Approved no
Call Number Serial 1781
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Author Gorokhov, G.; Bychanok, D.; Gayduchenko, I.; Rogov, Y.; Zhukova, E.; Zhukov, S.; Kadyrov, L.; Fedorov, G.; Ivanov, E.; Kotsilkova, R.; Macutkevic, J.; Kuzhir, P.
Title THz spectroscopy as a versatile tool for filler distribution diagnostics in polymer nanocomposites Type Journal Article
Year 2020 Publication Polymers (Basel) Abbreviated Journal Polymers (Basel)
Volume 12 Issue 12 Pages 3037 (1 to 14)
Keywords THz spectroscopy; nanocomposites, percolation threshold, time-domain spectroscopy, time-domain spectrometer, TDS
Abstract (up) Polymer composites containing nanocarbon fillers are under intensive investigation worldwide due to their remarkable electromagnetic properties distinguished not only by components as such, but the distribution and interaction of the fillers inside the polymer matrix. The theory herein reveals that a particular effect connected with the homogeneity of a composite manifests itself in the terahertz range. Transmission time-domain terahertz spectroscopy was applied to the investigation of nanocomposites obtained by co-extrusion of PLA polymer with additions of graphene nanoplatelets and multi-walled carbon nanotubes. The THz peak of permittivity's imaginary part predicted by the applied model was experimentally shown for GNP-containing composites both below and above the percolation threshold. The physical nature of the peak was explained by the impact on filler particles excluded from the percolation network due to the peculiarities of filler distribution. Terahertz spectroscopy as a versatile instrument of filler distribution diagnostics is discussed.
Address Institute of Photonics, University of Eastern Finland, Yliopistokatu 7, FI-80101 Joensuu, Finland
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ISSN 2073-4360 ISBN Medium
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Notes PMID:33353036; PMCID:PMC7767186 Approved no
Call Number Serial 1780
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