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Author Titova, N.; Kardakova, A. I.; Tovpeko, N.; Ryabchun, S.; Mandal, S.; Morozov, D.; Klemencic, G. M.; Giblin, S. R.; Williams, O. A.; Goltsman, G. N.; Klapwijk, T. M.
Title Slow electron–phonon cooling in superconducting diamond films Type Journal Article
Year 2017 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 27 Issue (down) 4 Pages 1-4
Keywords superconducting diamond films, electron-phonon cooling
Abstract We have measured the electron-phonon energy-relaxation time, τ eph , in superconducting boron-doped diamond films grown on silicon substrate by chemical vapor deposition. The observed electron-phonon cooling times vary from 160 ns at 2.70 K to 410 ns at 1.8 K following a T -2-dependence. The data are consistent with the values of τ eph previously reported for single-crystal boron-doped diamond films epitaxially grown on diamond substrate. Such a noticeable slow electron-phonon relaxation in boron-doped diamond, in combination with a high normal-state resistivity, confirms a potential of superconducting diamond for ultrasensitive superconducting bolometers.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1168
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Author Iomdina, E. N.; Seliverstov, S. V.; Teplyakova, K. O.; Jani, E. V.; Pozdniakova, V. V.; Polyakova, O. N.; Goltsman, G. N.
Title Terahertz scanning of the rabbit cornea with experimental UVB-induced damage: in vivo assessment of hydration and its verification Type Journal Article
Year 2021 Publication J. Biomed. Opt. Abbreviated Journal J. Biomed. Opt.
Volume 26 Issue (down) 4 Pages
Keywords medicine; scheimpflug imaging; UVB; confocal microscopy; cornea; optical coherent tomography; rabbit eyes; terahertz radiation
Abstract SIGNIFICANCE: Water content plays a vital role in the normally functioning visual system; even a minor disruption in the water balance may be harmful. Today, no direct method exists for corneal hydration assessment, while it could be instrumental in early diagnosis and control of a variety of eye diseases. The use of terahertz (THz) radiation, which is highly sensitive to water content, appears to be very promising. AIM: To find out how THz scanning parameters of corneal tissue measured by an experimental setup, specially developed for in vivo contactless estimations of corneal reflectivity coefficient (RC), are related to pathological changes in the cornea caused by B-band ultraviolet (UVB) exposure. APPROACH: The setup was tested on rabbit eyes in vivo. Prior to the course of UVB irradiation and 1, 5, and 30 days after it, a series of examinations of the corneal state was made. At the same time points, corneal hydration was assessed by measuring RC. RESULTS: The obtained data confirmed the negative impact of UVB irradiation course on the intensity of tear production and on the corneal thickness and optical parameters. A significant (1.8 times) increase in RC on the 5th day after the irradiation course, followed by a slight decrease on the 30th day after it was revealed. The RC increase measured 5 days after the UVB irradiation course generally corresponded to the increase (by a factor of 1.3) of tear production. RC increase occurred with the corneal edema, which was manifested by corneal thickening (by 18.2% in the middle area and 17.6% in corneal periphery) and an increased volume of corneal tissue (by 17.6%). CONCLUSIONS: Our results demonstrate that the proposed approach can be used for in vivo contactless estimation of the reflectivity of rabbit cornea in the THz range and, thereby, of cornea hydration.
Address National Research University Higher School of Economics, Moscow Institute of Electronics and Mathema, Russia
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1083-3668 ISBN Medium
Area Expedition Conference
Notes PMID:33834684; PMCID:PMC8027227 Approved no
Call Number Serial 1258
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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.
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 (down) 4 Pages 257-262
Keywords 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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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1829-1171 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1291
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Author Iomdina, E. N.; Seliverstov, S. V.; Sianosyan, A. A.; Teplyakova, K. O.; Rusova, A. A.; Goltsman, G. N.
Title Terahertz scanning for evaluation of corneal and scleral hydration Type Journal Article
Year 2018 Publication Sovremennye tehnologii v medicine Abbreviated Journal STM
Volume 10 Issue (down) 4 Pages 143-149
Keywords BWO; Golay cell; medicine; cornea; sclera; THz radiation; corneal hydration; backward-wave oscillator; avalanche transit-time diode; IMPATT diode
Abstract The aim of the investigation was to study the prospects of using continuous THz scanning of the cornea and the sclera to determine water concentration in these tissues and on the basis of the obtained data to develop the experimental installation for monitoring corneal and scleral hydration degree.Materials and Methods. To evaluate corneal and scleral transmittance and reflectance spectra in the THz range, the developed experimental installations were used to study 3 rabbit corneas and 3 scleras, 2 whole rabbit eyes, and 3 human scleras. Besides, two rabbit eyes were studied in vivo prior to keratorefractive surgery as well as 10 and 21 days following the surgery (LASIK).Results. There have been created novel experimental installations enabling in vitro evaluation of frequency dependence of corneal and scleral transmittance coefficients and reflectance coefficients on water percentage in the THz range. Decrease in corneal water content by 1% was found to lead to reliably established decrease in the reflected signal by 13%. The reflectance spectrum of the whole rabbit eye was measured in the range of 0.13–0.32 THz. The study revealed the differences between the indices of rabbit cornea and sclera, as well as rabbit and human sclera. There was developed a laboratory model of the installation for in vivo evaluation of corneal and scleral hydration using THz radiation.Conclusion. The preliminary findings show that the proposed technique based on the use of continuous THz radiation can be employed to create a device for noninvasive control of corneal and scleral hydration.
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Notes Approved no
Call Number Serial 1315
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Author Antipov, S. V.; Svechnikov, S. I.; Smirnov, K. V.; Vakhtomin, Y. B.; Finkel, M. I.; Goltsman, G. N.; Gershenzon, E. M.
Title Noise temperature of quasioptical NbN hot electron bolometer mixers at 900 GHz Type Journal Article
Year 2001 Publication Physics of Vibrations Abbreviated Journal Physics of Vibrations
Volume 9 Issue (down) 4 Pages 242-245
Keywords NbN HEB mixers
Abstract
Address
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1069-1227 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1550
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