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Author Bell, M.; Sergeev, A.; Mitin, V.; Bird, J.; Verevkin, A.; Gol’tsman, G. url  doi
openurl 
  Title One-dimensional resistive states in quasi-two-dimensional superconductors: Experiment and theory Type Journal Article
  Year 2007 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B  
  Volume 76 Issue 9 Pages 094521 (1 to 5)  
  Keywords (down) uasi-two-dimensional superconductors, NbN  
  Abstract We investigate competition between one- and two-dimensional topological excitations—phase slips and vortices—in the formation of resistive states in quasi-two-dimensional superconductors in a wide temperature range below the mean-field transition temperature TC0. The widths w=100nm of our ultrathin NbN samples are substantially larger than the Ginzburg-Landau coherence length ξ=4nm, and the fluctuation resistivity above TC0 has a two-dimensional character. However, our data show that the resistivity below TC0 is produced by one-dimensional excitations—thermally activated phase slip strips (PSSs) overlapping the sample cross section. We also determine the scaling phase diagram, which shows that even in wider samples the PSS contribution dominates over vortices in a substantial region of current and/or temperature variations. Measuring the resistivity within 7 orders of magnitude, we find that the quantum phase slips can only be essential below this level.  
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  Series Volume Series Issue Edition  
  ISSN 1098-0121 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1423  
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Author Finkel, M.; Thierschmann, H.; Galatro, L.; Katan, A. J.; Thoen, D. J.; de Visser, P. J.; Spirito, M.; Klapwijk, T. M. url  doi
openurl 
  Title Performance of THz components based on microstrip PECVD SiNx technology Type Journal Article
  Year 2017 Publication IEEE Trans. THz Sci. Technol. Abbreviated Journal IEEE Trans. THz Sci. Technol.  
  Volume 7 Issue 6 Pages 765-771  
  Keywords (down) transmission line measurements, power transmission lines, dielectrics, couplers, submillimeter wave circuits, coplanar waveguides, micromechanical devices  
  Abstract We present a performance analysis of passive THz components based on Microstrip transmission lines with a 2-μmthin plasma-enhanced chemical vapor deposition grown silicon nitride (PECVD SiNX) dielectric layer. A set of thru-reflect-line calibration structures is used for basic transmission line characterizations. We obtain losses of 9 dB/mm at 300 GHz. Branchline hybrid couplers are realized that exhibit 2.5-dB insertion loss, 1-dB amplitude imbalance, and -26-dB isolation, in agreement with simulations. We use the measured center frequency to determine the dielectric constant of the PECVD SiN x , which yields 5.9. We estimate the wafer-to-wafer variations to be of the order of 1%. Directional couplers are presented which exhibit -12-dB transmission to the coupled port and -26 dB to the isolated port. For transmission lines with 5-μm-thin silicon nitride (SiN x ), we observe losses below 4 dB/mm. The thin SiN x dielectric membrane makes the THz components compatible with scanning probe microscopy cantilevers allowing the application of this technology in on-chip circuits of a THz near-field microscope.  
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  Series Volume Series Issue Edition  
  ISSN 2156-342X ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1294  
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Author Tovpeko, N. A.; Trifonov, A. V.; Semenov, A. V.; Antipov, S. V.; Kaurova, N. S.; Titova, N. A.; Goltsman, G. N. url  openurl
  Title Bandwidth performance of a THz normal metal TiN bolometer-mixer Type Conference Article
  Year 2019 Publication Proc. 30th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 30th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 102-103  
  Keywords (down) TiN normal metal bolometer, NMB  
  Abstract We report on the bandwidth performance of the normal metal TiN bolometer-mixer on top of an Al 2 O 3 substrate, which is capable to operate in a wide range of bath temperatures from 77 K – 300 K. The choice of the combination TiN / Al 2 O 3 is related to an advanced heat transport between the film and the substrate in this pair and the sufficient temperature coefficient of resistance. The data were taken at 132.5 – 145.5 GHz with two BWOs as a signal and an LO source. Measurements were taken on TiN films of different thickness starting from 20 nm down to 5 nm coupled into a spiral Au antenna, which improves matching of incoming radiation with the thin TiN fim. Our experiments demonstrate effective heat coupling from a TiN thin film to an Al 2 O 3 substrate (111) boosting gain bandwidth (GB) of TiN bolometer up to 6 GHz for 5 nm thin film. Current results indicate weak temperature dependence of GB on the bath temperature of the TiN bolometer. Theoretical estimations of GB performance meet with experimental data for 5 nm thin TiN films.  
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  Notes Approved no  
  Call Number Serial 1279  
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Author Kardakova, A. I.; Coumou, P. C. J. J.; Finkel, M. I.; Morozov, D. V.; An, P. P.; Goltsman, G. N.; Klapwijk, T. M. url  doi
openurl 
  Title Electron–phonon energy relaxation time in thin strongly disordered titanium nitride films Type Journal Article
  Year 2015 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 25 Issue 3 Pages 1-4  
  Keywords (down) TiN MKID  
  Abstract We have measured the energy relaxation times from the electron bath to the phonon bath in strongly disordered TiN films grown by atomic layer deposition. The measured values of τ eph vary from 12 to 91 ns. Over a temperature range from 3.4 to 1.7 K, they follow T -3 temperature dependence, which are consistent with values of τ eph reported previously for sputtered TiN films. For the most disordered film, with an effective elastic mean free path of 0.35 nm, we find a faster relaxation and a stronger temperature dependence, which may be an additional indication of the influence of strong disorder on a superconductor.  
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  Series Editor Series Title Abbreviated Series Title  
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  ISSN 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1296  
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Author Кардакова, А. И.; Финкель, М. И.; Морозов, Д. В.; Ковалюк, В. В.; Ан, П. П.; Гольцман, Г. Н. url  openurl
  Title Время электрон-фононного взаимодействия в сверхпроводниковых пленках нитрида титана Type Conference Article
  Year 2014 Publication Труды XVIII международного симпозиума «Нанофизика и наноэлектроника» Abbreviated Journal  
  Volume 1 Issue Pages 47-48  
  Keywords (down) TiN films  
  Abstract Определены времена электрон-фононного взаимодействия в тонких сверхпроводниковых пленках нитрида титана. Измеренные значения τ_eph находятся в диапазоне от 5.5 нс до 88 нс при температурах 4,2 К и 1,7 К, соответственно, и соответствуют температурной зависимости Т^-3.  
  Address Нижний Новгород, Россия  
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  Language Russian Summary Language Original Title  
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  Notes Approved no  
  Call Number Serial 1835  
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Author Gol'tsman, Gregory; Semenov, Alexei; Smirnov, Konstantin; Voronov, Boris url  openurl
  Title Background limited quantum superconducting detector for submillimeter wavelengths Type Conference Article
  Year 2001 Publication Proc. 12th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 12th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 469-475  
  Keywords (down) Ti SQD, SQUID readout  
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  Notes Approved no  
  Call Number Serial 1540  
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Author Nikoghosyan, A. S.; Martirosyan, R. M.; Hakhoumian, A. A.; Makaryan, A. H.; Tadevosyan, V. R.; Goltsman, G. N.; Antipov, S. V. url  openurl
  Title Effect of absorption on the efficiency of THz radiation generation in a nonlinear crystal placed into a waveguide Type Journal Article
  Year 2018 Publication Armenian J. Phys. Abbreviated Journal Armenian J. Phys.  
  Volume 11 Issue 4 Pages 257-262  
  Keywords (down) THz, waveguide, nonlinear crystal  
  Abstract The effect of THz radiation absorption on the efficiency of generation of coherent THz radiation in a nonlinear optical crystal placed into a metal rectangular waveguide is studied. The efficiency of the nonlinear conversion of optical laser radiation to the THz band is also a function of the phase-matching (PM) condition inside the nonlinear crystal. The method of partial filling of a metal waveguide with a nonlinear optical crystal is used to ensure phase matching. Phase matching was obtained by the proper choice of the thickness of the nonlinear crystal, namely the degree of partial filling of the waveguide. We have studied the THz radiation attenuation caused by the losses in both the metal walls of the waveguide and in the crystal, taking into account the dimension of the cross section of the waveguide, the degree of partial filling and its dielectric constant.  
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  ISSN 1829-1171 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1291  
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Author Bandurin, D. A.; Svintsov, D.; Gayduchenko, I.; Xu, S. G.; Principi, A.; Moskotin, M.; Tretyakov, I.; Yagodkin, D.; Zhukov, S.; Taniguchi, T.; Watanabe, K.; Grigorieva, I. V.; Polini, M.; Goltsman, G. N.; Geim, A. K.; Fedorov, G. doi  openurl
  Title Resonant terahertz detection using graphene plasmons Type Journal Article
  Year 2018 Publication Nat. Commun. Abbreviated Journal Nat. Commun.  
  Volume 9 Issue Pages 5392 (1 to 8)  
  Keywords (down) THz, graphene plasmons  
  Abstract Plasmons, collective oscillations of electron systems, can efficiently couple light and electric current, and thus can be used to create sub-wavelength photodetectors, radiation mixers, and on-chip spectrometers. Despite considerable effort, it has proven challenging to implement plasmonic devices operating at terahertz frequencies. The material capable to meet this challenge is graphene as it supports long-lived electrically tunable plasmons. Here we demonstrate plasmon-assisted resonant detection of terahertz radiation by antenna-coupled graphene transistors that act as both plasmonic Fabry-Perot cavities and rectifying elements. By varying the plasmon velocity using gate voltage, we tune our detectors between multiple resonant modes and exploit this functionality to measure plasmon wavelength and lifetime in bilayer graphene as well as to probe collective modes in its moire minibands. Our devices offer a convenient tool for further plasmonic research that is often exceedingly difficult under non-ambient conditions (e.g. cryogenic temperatures) and promise a viable route for various photonic applications.  
  Address Physics Department, Moscow State University of Education (MSPU), Moscow, Russian Federation, 119435. fedorov.ge@mipt.ru  
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  ISSN 2041-1723 ISBN Medium  
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  Notes Approved no  
  Call Number Serial 1148  
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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. url  doi
openurl 
  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 (down) THz spectroscopy; nanocomposites, percolation threshold, time-domain spectroscopy, time-domain spectrometer, TDS  
  Abstract 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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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 2073-4360 ISBN Medium  
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  Notes PMID:33353036; PMCID:PMC7767186 Approved no  
  Call Number Serial 1780  
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Author Neroev, V. V.; Iomdina, E. N.; Khandzhyan, A. T.; Khodzhabekyan, N. V.; Sengaeva, M. D.; Ivanova, A. V.; Seliverstov, S. V.; Teplyakova, K. O.; Goltsman, G. N. url  doi
openurl 
  Title Experimental study of the effect of corneal hydration and its biomechanical properties on the results of photorefractive keratectomy Type Journal Article
  Year 2021 Publication Vestn. Oftalmol. Abbreviated Journal Vestn. Oftalmol.  
  Volume 137 Issue 3 Pages 68-75  
  Keywords (down) THz scanning, cornea, photorefractive keratectomy, medicine  
  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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  Language Russian Summary Language Original Title  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1794  
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