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| Author | Averkin, A. S.; Shishkin, A. G.; Chichkov, V. I.; Voronov, B. M.; Goltsman, G. N.; Karpov, A.; Ustinov, A. V. | ||||
| Title | Tunable frequency-selective surface based on superconducting split-ring resonators | Type | Conference Article | ||
| Year | 2014 | Publication | 8th Metamaterials | Abbreviated Journal | 8th Metamaterials |
| Volume | Issue | Pages | |||
| Keywords | superconducting split-ring resonators | ||||
Abstract  |
We study a possibility to use the 2D superconducting metamaterial as a tunable frequency-selective surface (FSS). The proposed FSS is made of sub-wavelength size (l/14) metamaterial unit cells, where a split-ring resonator is embedded in a small iris aperture in a metal plane. The split-ring resonator is made of NbN film, and its resonance frequency is tuned by the temperature of the sample, changing the kinetic inductance of NbN film. The Ansoft HFSS simulation predicts the FSS tuning range of about 10-20 %. The developed superconducting FSS may be used as a tunable band-pass filter or modulator. | ||||
| Address | Copenhagen, Denmark | ||||
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| Area | Expedition | Conference | 8th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics – Metamaterials | ||
| Notes | Approved | no | |||
| Call Number | Serial | 1749 | |||
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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. | ||||
| 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 | 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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| Author | Semenov, A. D.; Heusinger, M. A.; Renk, K. F.; Menschikov, E.; Sergeev, A. V.; Elant'ev, A. I.; Goghidze, I. G.; Gol'tsman, G. N. | ||||
| Title | Influence of phonon trapping on the performance of NbN kinetic inductance detectors | Type | Journal Article | ||
| Year | 1997 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
| Volume | 7 | Issue | 2 | Pages | 3083-3086 |
| Keywords | NbN KID | ||||
| Abstract |
Voltage and microwave photoresponse of NbN thin films to modulated and pulsed optical radiation reveals, far below the superconducting transition, a response time consistent with the lifetime of nonequilibrium quasiparticles. We show that even in 5 nm thick films at 4.2 K the phonon trapping is significant resulting in a quasiparticle lifetime of a few nanoseconds that is an order of magnitude larger than the recombination time. Values and temperature dependence of the quasiparticle lifetime obey the Bardeen-Cooper-Schrieffer theory and are in quantitative agreement with the electron-phonon relaxation rate determined from the resistive response near the superconducting transition. We discuss a positive effect of the phonon trapping on the performance of kinetic inductance detectors. | ||||
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| ISSN | 1051-8223 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1598 | |||
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| Author | Fedorov, G. E.; Stepanova, T. S.; Gazaliev, A. S.; Gaiduchenko, I. A.; Kaurova, N. S.; Voronov, B. M.; Goltzman, G. N. | ||||
| Title | Asymmetric devices based on carbon nanotubes for terahertz-range radiation detection | Type | Journal Article | ||
| Year | 2016 | Publication | Semicond. | Abbreviated Journal | Semicond. |
| Volume | 50 | Issue | 12 | Pages | 1600-1603 |
| Keywords | carbon nanotubes, CNT detectors | ||||
| Abstract |
Various asymmetric detecting devices based on carbon nanotubes (CNTs) are studied. The asymmetry is understood as inhomogeneous properties along the conducting channel. In the first type of devices, an inhomogeneous morphology of the CNT grid is used. In the second type of devices, metals with highly varying work functions are used as the contact material. The relation between the sensitivity and detector configuration is analyzed. Based on the data obtained, approaches to the development of an efficient detector of terahertz radiation, based on carbon nanotubes are proposed. | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1063-7826 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1776 | |||
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| Author | Galin, M. A.; Klushin, A. M.; Kurin, V. V.; Seliverstov, S. V.; Finkel, M. I.; Goltsman, G. N.; Müller, F.; Scheller, T.; Semenov, A. D. | ||||
| Title | Towards local oscillators based on arrays of niobium Josephson junctions | Type | Journal Article | ||
| Year | 2015 | Publication | Supercond. Sci. Technol. | Abbreviated Journal | Supercond. Sci. Technol. |
| Volume | 28 | Issue | 5 | Pages | 055002 (1 to 7) |
| Keywords | Josephson junction local oscillators, JJ LO | ||||
| Abstract |
Various applications in the field of terahertz technology are in urgent need of compact, wide-tunable solid-state continuous wave radiation sources with a moderate power. However, satisfactory solutions for the THz frequency range are scarce yet. Here we report on coherent radiation from a large planar array of Josephson junctions (JJs) in the frequency range between 0.1 and 0.3 THz. The external resonator providing the synchronization of JJ array is identified as a straight fragment of a single-strip-line containing the junctions themselves. We demonstrate a prototype of the quasioptical heterodyne receiver with the JJ array as a local oscillator and a hot-electron bolometer mixer. | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0953-2048 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1347 | |||
| Permanent link to this record | |||||