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| Author | Gershenzon, Ye. M.; Goltsman, G. N.; Yelantyev, A. I.; Petrova, Ye. B.; Ptitsina, N. G.; Filatov, V. S. | ||||
| Title | Lecture demonstrations of properties of superconductors and liquid helium | Type | Journal Article | ||
| Year | 1987 | Publication | USSR Rept Phys. Math. JPRS UPM | Abbreviated Journal | USSR Rept Phys. Math. JPRS UPM |
| Volume | 24 | Issue | 7 | Pages  |
51 |
| Keywords | demonstrations, lections | ||||
| Abstract | New demonstrations for low temperature physics courses are described. Two transparent Dewar vacuum flasks fitting one inside the other with the external flask for nitrogen and the internal flask for helium are used. The helium temperature can be regulated in the 4.2 to 1.6 K range and the effects of reducing helium to the superfluid state at 2.17 K can be shown: boiling abruptly stops and superfluid flow appears. In order to show the electric and magnetic characteristics of superconductivity, a superconducting NbTi solenoid containing nonsuperconducting wire and germanium and superconducting Nb materials with different critical temperatures is placed in the helium refrigerant vessel. The fall of the resistance at the critical temperatures can be shown. In order to show magnetic field and superconductive current flow properties a shunt of superconductive material is connected in parallel to the coil and is enclosed in a teflon container with a heater which can vary its temperature. When it is heated and not superconductive, magnetic field effects can be demonstrated and when it is unheated and superconducting a continuous current can be demonstrated. | ||||
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| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1704 | |||
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| Author | Verevkin, A. A.; Ptitsina, N. G.; Smirnov, K. V.; Goltsman, G. N.; Gershenson, E. M.; Yngvesson, K. S. | ||||
| Title | Direct measurements of electron energy relaxation times at an AlGaAs/GaAs heterointerface in the optical phonon scattering range | Type | Conference Article | ||
| Year | 1997 | Publication | Proc. 4-th Int. Semicond. Device Research Symp. | Abbreviated Journal | Proc. 4-th Int. Semicond. Device Research Symp. |
| Volume | Issue | Pages |
55-58 | ||
| Keywords | 2DEG, AlGaAs/GaAs heterostructures | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 1602 | |||
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| Author | Ryabchun, S. A.; Tretyakov, I. V.; Finkel, M. I.; Maslennikov, S. N.; Kaurova, N. S.; Seleznev, V. A.; Voronov, B. M.; Goltsman, G. N. | ||||
| Title | Fabrication and characterisation of NbN HEB mixers with in situ gold contacts | Type | Conference Article | ||
| Year | 2008 | Publication | Proc. 19th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 19th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages |
62-67 | ||
| Keywords | HEB, mixer, NbN, in-situ contacts | ||||
| Abstract | We present our recent results of the fabrication and testing of NbN hot-electron bolometer mixers with in situ gold contacts. An intermediate frequency bandwidth of about 6 GHz has been measured for the mixers made of a 3.5-nm NbN film on a plane Si substrate with in situ gold contacts, compared to 3.5 GHz for devices made of the same film with ex situ gold contacts. The increase in the intermediate frequency bandwidth is attributed to additional diffusion cooling through the improved contacts, which is further supported by the its dependence on the bridge length: intermediate frequency bandwidths of 3.5 GHz and 6 GHz have been measured for devices with lengths of 0.35 μm and 0.16 μm respectively at a local oscillator frequency of 300 GHz near the superconducting transition. At a local oscillator frequency of 2.5 THz the receiver has offered a DSB noise temperature of 950 K. When compared to the previous result of 1300 K obtained at the same local oscillator frequency for devices fabricated with an ex situ route, such a low value of the noise temperature may also be attributed to the improved gold contacts. | ||||
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| Publisher | Place of Publication | Groningen, Netherlands | Editor | ||
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| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 412 | |||
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| Author | Korneev, A.; Finkel, M.; Maslennikov, S.; Korneeva, Yu.; Florya, I.; Tarkhov, M.; Elezov, M.; Ryabchun, S.; Tretyakov, I.; Isupova, A.; Voronov, B.; Goltsman, G. | ||||
| Title | Superconducting NbN terahertz detectors and infrared photon counters | Type | Journal Article | ||
| Year | 2010 | Publication | Вестник НГУ. Серия: физ. | Abbreviated Journal | Вестник НГУ. Серия: физ. |
| Volume | 5 | Issue | 4 | Pages |
68-72 |
| Keywords | HEB; HEB mixer | ||||
| Abstract | We present our recent achievements in the development of sensitive and ultrafast thin-film superconducting sensors: hot-electron bolometers (HEB), HEB-mixers for terahertz range and infrared single-photon counters. These sensors have already demonstrated a performance that makes them devices-of-choice for many terahertz and optical applications. Keywords: Hot electron bolometer mixers, infrared single-photon detectors, superconducting device fabrication, superconducting NbN films. | ||||
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| ISSN | 1818-7994 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | УДК 538.9 | Approved | no | ||
| Call Number | RPLAB @ gujma @ | Serial | 708 | ||
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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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| Notes | Approved | no | |||
| Call Number | Serial | 1794 | |||
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| Author | Fedorov, G.; Kardakova, A.; Gayduchenko, I.; Voronov, B. M.; Finkel, M.; Klapwijk, T. M.; Goltsman, G. | ||||
| Title | Photothermoelectric response in asymmetric carbon nanotube devices exposed to sub-THz radiation | Type | Abstract | ||
| Year | 2014 | Publication | Proc. 25th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 25th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages |
71 | ||
| Keywords | carbon nanotubes, CNT | ||||
| Abstract | This work reports on the voltage response of asymmetric carbon nanotube devices to sub-THz radiation at the frequency of 140 GHz. The devices contain CNT’s, which are over their length partially suspended and partially Van der Waals bonded to a SiO 2 substrate, causing a difference in thermal contact. Different heat sinking of CNTs by source and drain gives rise to temperature gradient and consequent thermoelectric power (TEP) as such a device is exposed to the sub-THz radiation. Sign of the DC signal, its power and gate voltage dependence observed at room temperature are consistent with this scenario. At liquid helium temperature the observed response is more complex. DC voltage signal of an opposite sign is observed in a narrow range of gate voltages at low temperatures and under low radiation power. We argue that this may indicate a true photovoltaic response from small gap (less than 10meV) CNT’s, an effect never reported before. While it is not clear if the observed effects can be used to develop efficient THz detectors we note that the responsivity of our devices exceeds that of CNT based devices in microwave or THz range reported before at room temperature. Besides at 4.2 K notable increase of the sample conductance (at least four-fold) is observed. Our recent results with asymmetric carbon nanotube devices response to THz radiation (2.5 THz) will also be presented. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 1361 | |||
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| Author | Korneev, A.; Korneeva, Y.; Florya, I.; Voronov, B.; Goltsman, G. | ||||
| Title | NbN nanowire superconducting single-photon detector for mid-infrared | Type | Journal Article | ||
| Year | 2012 | Publication | Phys. Procedia | Abbreviated Journal | Phys. Procedia |
| Volume | 36 | Issue | Pages |
72-76 | |
| Keywords | NbN SSPD, SNSPD | ||||
| Abstract | Superconducting single-photon detectors (SSPD) is typically 100 nm-wide supercondiucting strip in a shape of meander made of 4-nm-thick film. To reduce response time and increase voltage response a parallel connection of the strips was proposed. Recently we demonstrated that reduction of the strip width improves the quantum effciency of such a detector at wavelengths longer than 1.5 μm. Being encourage by this progress in quantum effciency we improved the fabrication process and made parallel-wire SSPD with 40-nm-wide strips covering total area of 10 μm x 10 μm. In this paper we present the results of the characterization of such a parallel-wire SSPD at 10.6 μm wavelength and demonstrate linear dependence of the count rate on the light power as it should be in case of single-photon response. | ||||
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| ISSN | 1875-3892 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1382 | |||
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| Author | Tiulina, V.; Iomdina, E.; Goltsman, G.; Seliverstov, S.; Sianosyan, A.; Teplyakova, K.; Rusova, A.; Zaitsev, S.; Zernii, E.; Senin, I. | ||||
| Title | UVB promotes the initiation of uveitic inflammatory and changes in thehydration of the cornea in vivo | Type | Miscellaneous | ||
| Year | 2019 | Publication | FEBS Open Bio | Abbreviated Journal | FEBS Open Bio |
| Volume | 9 | Issue | S1 | Pages |
79 |
| Keywords | medicine; scheimpflug imaging; UVB; confocal microscopy; cornea; optical coherent tomography; rabbit eyes; terahertz radiation | ||||
| Abstract | Recently, active research has been conducted in the field of terahertz (THz) scanning of human tissues for noninvasive determination of their hydration level, which haves hown high diagnostic efficiency of this technology in various pathological conditions. Recently, we have developed a laboratory model of the facility for monitoring the state of the water balance of the cornea using THz scanning in vivo, which opens up the possibility of applying this approach in ophthalmology. The aim of the work wasto compare the results of the THz scan of the cornea with its clinical changes using the example of an experimental model of the UV induced keratouveitis. Anexperimental study, which included a comprehensive assessment of clinical changes in the cornea of rabbits during keratouveitis induction, revealed a decrease in the stability of the tear film, pathological changes in the corneal epithelium and stroma, as well as its anatomical and optical parameters. Comparison of data obtained in the THz scan of the cornea with tears production, optical coherence tomography and confocal microscopy showed their consistency in all observation periods, which allows us to conclude that the developed laboratory setup works and the feasibility of further research to promote the corneal hydration evaluation technology in clinical practice. Acknowledgements: Research was funded by the RSF, grant number 161500255. | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 2211-5463 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Poster P-01-040 | Approved | no | ||
| Call Number | Serial | 1276 | |||
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| Author | Titova, N; Kardakova, A.; Tovpeko, N; Ryabchun, S.; Mandal, S.; Morozov, D.; Klemencic, G. M.; Giblin, S.R.; Williams, O. A.; Goltsman, G. N. | ||||
| Title | Superconducting diamond films as perspective material for direct THz detectors | Type | Abstract | ||
| Year | 2017 | Publication | Proc. 28th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 28th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages |
82 | ||
| Keywords | KID, HEB, superconducting diamond films, boron-doped diamond films, Al, TiN, Si substrates, NEP | ||||
| Abstract | Superconducting films with a high resistivity in the normal state have established themselves as the best materials for direct THz radiation sensors, such as kinetic inductance detectors (KIDs) [1] and hot electron bolometers (nano-HEBs) [2]. The primary characteristics of the future instrument such as the sensitivity and the response time are determined by the material parameters such as the electron-phonon (e-ph) interaction time, the electron density and the resistivity of the material. For direct detectors, such as KIDs and nano-HEBs, to provide a high sensitivity and low noise one prefer materials with long e-ph relaxation times and low values of the electron density. As a potential material for THz radiation detection we have studied superconducting diamond films. A significant interest to diamond for the development of electronic devices is due to the evolution of its properties with the boron dopant concentration. At a high boron doping concentration, n B ~5·10 20 cm -3 , diamond has been reported to become a superconducting with T c depending on the doping level. Our previous study of energy relaxation in single-crystalline boron-doped diamond films epitaxially grown on a diamond shows a remarkably slow energy-relaxation at low temperatures. The electron-phonon cooling time varies from 400 ns to 700 ns over the temperature range 2.2 K to 1.7 K [3]. In superconducting materials such as Al and TiN, traditionally used in KIDs, the e-ph cooling times at 1.7 K correspond to ~20 ns [4] and ~100 ns [5], correspondingly. Such a noticeable slow e-ph relaxation in boron-doped diamond, in combination with a low value of carrier density (~10 21 cm -3 ) in comparison with typical metals (~10 23 cm -3 ) and a high normal state resistivity (~1500 μΩ·cm) confirms a potential of superconducting diamond for superconducting bolometers and resonator detectors. However, the price and the small substrate growth are of single crystal diamond limit practical applications of homoepitaxial diamond films. As an alternative way with more convenient technology, one can employ heteroepitaxial diamond films grown on large-size Si substrates. Here we report about measurements of e-ph cooling times in superconducting diamond grown on silicon substrate and discuss our expectations about the applicability of boron-doped diamond films to superconducting detectors. Our estimation of limit value of noise-equivalent power (NEP) and the energy resolution of bolometer made from superconducting diamond is order 10 -17 W/Hz 1/2 at 2 K and the energy resolution is of 0.1 eV that corresponds to counting single-photon up to 15 um. The estimation was obtained by using the film thickness of 70 nm and ρ ~ 1500 μΩ·cm, and the planar dimensions that are chosen to couple bolometer with 75 Ω log-spiral antenna. Although the value of NEP is far yet from what might like to have for certain astronomical applications, we believe that it can be improved by a suitable fabrication process. Also the direct detectors, based on superconducting diamond, will offer low noise performance at about 2 K, a temperature provided by inexpensive close-cycle refrigerators, which provides another practical advantage of development and application of these devices. [1] P.K. Day, et. al, Nature, 425, 817, 2003. [2] J. Wei, et al, Nature Nanotech., 3, 496, 2008. [3] A. Kardakova, et al, Phys. Rev. B, 93, 064506, 2016. [4] P. Santhanam and D. Prober, Phys. Rev. B, 29, 3733, 1984 [5] A. Kardakova, et al, Appl. Phys. Lett, vol. 103, p. 252602, 2013. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 1173 | |||
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| Author | Aksaev, E. E.; Gershenzon, E. M.; Gershenson, M. E.; Goltsman, G. N.; Semenov, A. D.; Sergeev, A. V. | ||||
| Title | Prospects for using high-temperature superconductors to create electron bolometers | Type | Journal Article | ||
| Year | 1989 | Publication | Pisma v Zhurnal Tekhnicheskoi Fiziki | Abbreviated Journal | Pisma v Zhurnal Tekhnicheskoi Fiziki |
| Volume | 15 | Issue | 14 | Pages |
88-93 |
| Keywords | HTS HEB | ||||
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| Language | Russian | Summary Language | Original Title | ||
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| ISSN | 0320-0116 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Перспективы применения высокотемпературных сверхпроводников для создания электронных болометров | Approved | no | ||
| Call Number | Serial | 1693 | |||
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