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Author Iomdina, E. N.; Seliverstov, S.; Sianosyan, A.; Teplyakova, K.; Rusova, A.; Goltsman, G.
Title The prospects of using the radiation for the assessment of corneal and scleral hydration Type Abstract
Year 2016 Publication (up) Acta Ophthalmol. Abbreviated Journal Acta Ophthalmol.
Volume 94 Issue Pages
Keywords BWO, avalanche transit‐time diode, medicine, biology
Abstract Purpose

An adequate water balance (hydration extent) is one of the basic factors of normal eye function, including its external shells – the cornea and the sclera. THz systems creating images in reflected beams are likely to become ideal instruments of noninvasive testing of corneal and scleral hydration degree as THz radiation is highly sensitive to water content. The paper aims at studying the transmittance and reflectance spectra of the cornea and the sclera of rabbit and human eyes, as well as those of the whole rabbit eye, in the frequency range of 0.13–0.32 THz.

Methods

The experiments were carried out on 3 corneas and 3 rabbit scleras, 2 whole rabbit eyes, and 3 human healthy adult scleras using a specially developed THz system based on reliable and easy‐to‐use continuous wave sources: a backward‐wave oscillator and an avalanche transit‐time diode.

Results

The transmittance spectra of the cornea and the sclera and the dependence of the reflection coefficient of these tissues in THz range on water percentage content were determined. Comparison of the rabbit cornea hydrated from 73.2% to 76.3% concentration by mass demonstrated an approximately linear relationship between THz reflectivity and water concentration. The decrease of free water concentration by 1% leads to a drop of the reflectance coefficient by 13%. The parameters studied displayed noticeable differences between the sclera and the cornea of rabbits and between rabbit sclera and human sclera.

Conclusions

Preliminary results demonstrate that the proposed technique, based on continuous THz radiation, may be used to create a device for noninvasive testing of corneal and scleral hydration, which has good potential of wide‐scale practical application.

The work was supported by the Russian Foundation of Basic Research (grant No.15‐29‐03843)
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ISSN 1755375X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1333
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Author Il'in, K.; Siegel, M.; Semenov, A.; Engel, A.; Hübers, H.-W.; Hollmann, E.; Gol'tsman, G.; Voronov, B.
Title Thickness dependence of superconducting properties of ultrathin Nb and NbN films Type Conference Article
Year 2004 Publication (up) AKF-Frühjahrstagung Abbreviated Journal
Volume Issue Pages
Keywords Nb, NbN films, has potential plagiarism
Abstract
Address Berlin-Adlershof
Corporate Author Thesis
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Notes Approved no
Call Number Serial 1503
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Author Bandurin, Denis; Svintsov, Dmitry; Gayduchenko, Igor; Xu, Shuigang; Principi, Alessandro; Moskotin, Maksim; Tretyakov, Ivan; Yagodkin, Denis; Zhukov, Sergey; Taniguchi, Takashi; Watanabe, Kenji; Grigorieva, Irina; Polini, Marco; Goltsman, Gregory; Geim, Andre; Fedorov, Georgy
Title Resonant terahertz photoresponse and superlattice plasmons in graphene field-effect transistors Type Abstract
Year 2019 Publication (up) APS March Meeting Abbreviated Journal APS March Meeting
Volume Issue Pages F14.015
Keywords
Abstract Plasmons, collective oscillations of electron systems, can couple light and electric current, and thus can be used to create compact photodetectors, radiation mixers, and spectrometers. Despite the effort, it has proven challenging to implement plasmonic devices operating at THz frequencies. The material capable to meet this challenge is graphene as it supports long-lived electrically-tunable plasmons. In this talk, we will demonstrate plasmon-assisted resonant detection of THz radiation by antenna-coupled graphene FETs that act as both rectifying elements and plasmonic Fabry-Perot cavities amplifying the photoresponse. We will show that by varying the plasmon velocity using gate voltage, our detectors can be tuned between multiple resonant modes, a functionality that we apply to measure plasmons' wavelength and lifetime in graphene as well as to probe collective modes in its moire minibands. Our approach offers a convenient tool for further plasmonic research that is often difficult under non-ambient conditions and promises a viable route for various THz applications. We acknowledge Leverhulme Trust, Russian Science Foundation Grants N18-72-00234 and 17-72-30036, Russian Foundation for Basic Research No. 18-57-06001 and 16-29-03402.
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Call Number Serial 1290
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Author Beck, M.; Klammer, M.; Rousseau, I.; Gol’tsman, G. N.; Diamant, I.; Dagan, Y.; Demsar, J.
Title Probing superconducting gap dynamics with THz pulses Type Conference Article
Year 2015 Publication (up) CLEO Abbreviated Journal CLEO
Volume Issue Pages SM3H.3 (1 to 2)
Keywords superconducting gap; electric fields; femtosecond pulses; near infrared radiation; picosecond pulses; superconductors; thin films
Abstract We studied superconducting gap dynamics in a BCS superconductor NbN and electron doped cuprate superconductor PCCO following excitation with near-infrared (NIR) and narrow band THz pulses. Systematic studies on PCCO imply very selective electron-phonon coupling.
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Publisher Optical Society of America Place of Publication Editor
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Notes Approved no
Call Number Serial 1345
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Author Xu, Y.; Zheng, X.; Williams, C.; Verevkin, A.; Sobolewski, R.; Chulkova, G.; Lipatov, A.; Okunev, O.; Smirnov, K.; Gol’tsman, G. N.
Title Ultrafast superconducting hot-electron single-photon detector Type Conference Article
Year 2001 Publication (up) CLEO Abbreviated Journal CLEO
Volume Issue Pages 345
Keywords NbN SSPD, SNSPD
Abstract Summary form only given. The current most-pressing need is to develop a practical, GHz-range counting single-photon detector, operational at either 1.3-/spl mu/m or 1.55-/spl mu/m radiation wavelength, for novel quantum communication and quantum cryptography systems. The presented solution of the problem is to use an ultrafast hot-electron photodetector, based on superconducting thin-film microstructures. This type of device is very promising, due to the macroscopic quantum nature of superconductors. Very fast response time and the small, (meV range) value of the superconducting energy gap characterize the superconductor, leading to the efficient avalanche process even for infrared photons.
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Area Expedition Conference Technical Digest. Summaries of papers presented at the Conference on Lasers and Electro-Optics. Postconference Technical Digest (IEEE Cat. No.01CH37170)
Notes Approved no
Call Number Serial 1545
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