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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 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
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Language English Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 1083-3668 ISBN Medium
Area Expedition Conference
Notes (down) PMID:33834684; PMCID:PMC8027227 Approved no
Call Number Serial 1258
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Author Gayduchenko, I.; Xu, S. G.; Alymov, G.; Moskotin, M.; Tretyakov, I.; Taniguchi, T.; Watanabe, K.; Goltsman, G.; Geim, A. K.; Fedorov, G.; Svintsov, D.; Bandurin, D. A.
Title Tunnel field-effect transistors for sensitive terahertz detection Type Journal Article
Year 2021 Publication Nat. Commun. Abbreviated Journal Nat. Commun.
Volume 12 Issue 1 Pages 543
Keywords field-effect transistors, bilayer graphene, BLG
Abstract The rectification of electromagnetic waves to direct currents is a crucial process for energy harvesting, beyond-5G wireless communications, ultra-fast science, and observational astronomy. As the radiation frequency is raised to the sub-terahertz (THz) domain, ac-to-dc conversion by conventional electronics becomes challenging and requires alternative rectification protocols. Here, we address this challenge by tunnel field-effect transistors made of bilayer graphene (BLG). Taking advantage of BLG's electrically tunable band structure, we create a lateral tunnel junction and couple it to an antenna exposed to THz radiation. The incoming radiation is then down-converted by the tunnel junction nonlinearity, resulting in high responsivity (>4 kV/W) and low-noise (0.2 pW/[Formula: see text]) detection. We demonstrate how switching from intraband Ohmic to interband tunneling regime can raise detectors' responsivity by few orders of magnitude, in agreement with the developed theory. Our work demonstrates a potential application of tunnel transistors for THz detection and reveals BLG as a promising platform therefor.
Address Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. bandurin@mit.edu
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-1723 ISBN Medium
Area Expedition Conference
Notes (down) PMID:33483488; PMCID:PMC7822863 Approved no
Call Number Serial 1261
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Author Tretyakov, I.; Svyatodukh, S.; Perepelitsa, A.; Ryabchun, S.; Kaurova, N.; Shurakov, A.; Smirnov, M.; Ovchinnikov, O.; Goltsman, G.
Title Ag2S QDs/Si heterostructure-based ultrasensitive SWIR range detector Type Journal Article
Year 2020 Publication Nanomaterials (Basel) Abbreviated Journal Nanomaterials (Basel)
Volume 10 Issue 5 Pages 1-12
Keywords detector; quantum dots; short-wave infrared range; silicon
Abstract In the 20(th) century, microelectronics was revolutionized by silicon-its semiconducting properties finally made it possible to reduce the size of electronic components to a few nanometers. The ability to control the semiconducting properties of Si on the nanometer scale promises a breakthrough in the development of Si-based technologies. In this paper, we present the results of our experimental studies of the photovoltaic effect in Ag2S QD/Si heterostructures in the short-wave infrared range. At room temperature, the Ag2S/Si heterostructures offer a noise-equivalent power of 1.1 x 10(-10) W/ radicalHz. The spectral analysis of the photoresponse of the Ag2S/Si heterostructures has made it possible to identify two main mechanisms behind it: the absorption of IR radiation by defects in the crystalline structure of the Ag2S QDs or by quantum QD-induced surface states in Si. This study has demonstrated an effective and low-cost way to create a sensitive room temperature SWIR photodetector which would be compatible with the Si complementary metal oxide semiconductor technology.
Address Laboratory of nonlinear optics, Zavoisky Physical-Technical Institute of the Russian Academy of Sciences, Kazan 420029, Russia
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Language English Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 2079-4991 ISBN Medium
Area Expedition Conference
Notes (down) PMID:32365694; PMCID:PMC7712218 Approved no
Call Number Serial 1151
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Author Elezov, M.; Ozhegov, R.; Goltsman, G.; Makarov, V.
Title Countermeasure against bright-light attack on superconducting nanowire single-photon detector in quantum key distribution Type Journal Article
Year 2019 Publication Opt. Express Abbreviated Journal Opt. Express
Volume 27 Issue 21 Pages 30979-30988
Keywords SSPD, SNSPD
Abstract We present an active anti-latching system for superconducting nanowire single-photon detectors. We experimentally test it against a bright-light attack, previously used to compromise security of quantum key distribution. Although our system detects continuous blinding, the detector is shown to be partially blindable and controllable by specially tailored sequences of bright pulses. Improvements to the countermeasure are suggested.
Address
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Language English Summary Language Original Title
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ISSN 1094-4087 ISBN Medium
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Notes (down) PMID:31684339 Approved no
Call Number Serial 1275
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Author Gayduchenko, I. A.; Fedorov, G. E.; Moskotin, M. V.; Yagodkin, D. I.; Seliverstov, S. V.; Goltsman, G. N.; Yu Kuntsevich, A.; Rybin, M. G.; Obraztsova, E. D.; Leiman, V. G.; Shur, M. S.; Otsuji, T.; Ryzhii, V. I.
Title Manifestation of plasmonic response in the detection of sub-terahertz radiation by graphene-based devices Type Journal Article
Year 2018 Publication Nanotechnol. Abbreviated Journal Nanotechnol.
Volume 29 Issue 24 Pages 245204 (1 to 8)
Keywords single layer graphene, graphene nanoribbons
Abstract We report on the sub-terahertz (THz) (129-450 GHz) photoresponse of devices based on single layer graphene and graphene nanoribbons with asymmetric source and drain (vanadium and gold) contacts. Vanadium forms a barrier at the graphene interface, while gold forms an Ohmic contact. We find that at low temperatures (77 K) the detector responsivity rises with the increasing frequency of the incident sub-THz radiation. We interpret this result as a manifestation of a plasmonic effect in the devices with the relatively long plasmonic wavelengths. Graphene nanoribbon devices display a similar pattern, albeit with a lower responsivity.
Address Physics Department, Moscow State University of Education, Moscow 119991, Russia. National Research Center 'Kurchatov Institute', 123182, Moscow, Russia
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-4484 ISBN Medium
Area Expedition Conference
Notes (down) PMID:29553479 Approved no
Call Number Serial 1308
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