Records |
Author |
Gershenzon, E. M.; Gurvich, Yu. A.; Orlova, S. L.; Ptitsina, N. G. |
Title |
Cyclotron resonance of electrons in Ge in a quantizing magnetic field in the case of inelastic scattering by acoustic phonons |
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Journal Article |
Year |
1975 |
Publication |
Sov. Phys. JETP |
Abbreviated Journal |
Sov. Phys. JETP |
Volume |
40 |
Issue |
2 |
Pages |
311-315 |
Keywords |
Ge, cyclotron resonance |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Results are presented of an experimental study of the linewidth of cyclotron resonance under strong quantization conditions on the scattering of electrons by acoustic phonons. The measurements were performed in the 2....{).4 mm wavelength range at temperatures between 10 and 1.4 OK. A number of singularities were observed in the temperature and frequency dependences of the cyclotron linewidth. These can be ascribed to the effect of inhomogeneous broadening due to nonparabolicity of the electron spectrum, which is renormalized as a result of interaction with acoustic phonons. |
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1768 |
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Author |
Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G. |
Title |
Investigation of free excitons in Ge and their condensation at submillimeter wavelengths |
Type |
Journal Article |
Year |
1976 |
Publication |
Sov. Phys. JETP |
Abbreviated Journal |
Sov. Phys. JETP |
Volume |
43 |
Issue |
1 |
Pages |
116-122 |
Keywords |
Ge, free excitons |
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Results are presented of an investigation of free excitons in Ge in the submillimeter wavelength range for low as well as for high excitation levels when interaction between the excitons becomes important. The free-exciton energy spectrum is discussed. It is shown that the drop radii and their concentrations can be determined by measuring the temperature dependence of the free-exciton concentration. A section of the phase diagram is obtained in the 0.5-2.8 K temperature range for the free excitons+condensate system. |
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1731 |
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Tretyakov, Ivan; Kaurova, N.; Voronov, B. M.; Goltsman, G. N. |
Title |
About effect of the temperature operating conditions on the noise temperature and noise bandwidth of the terahertz range NbN hot-electron bolometers |
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Abstract |
Year |
2018 |
Publication |
Proc. 29th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 29th Int. Symp. Space Terahertz Technol. |
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Pages |
113 |
Keywords |
NbN HEB mixer |
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Results of an experimental study of the noise temperature (Tn) and noise bandwidth (NBW) of the superconductor NbN hot-electron bolometer (HEB) mixer as a function of its temperature (Tb) and NbN bridge length are presented. It was determined that the NBW of the mixer is significantly wider at temperatures close to the critical ones (Tc) than are values measured at 4.2 K. The NBW of the mixer measured at the heterodyne frequency of 2.5 THz at temperature Tb close to Tc was ~13 GHz, as compared with 6 GHz at Tb = 4.2 K. This experiment clearly demonstrates the limitation of the thermal flow from the NbN bridge at Tb ≪ Tc for mixers manufactured by the in situ technique. This limitation is close in its nature to the Andreev reflection on the superconductor/metal boundary. In this case, the noise temperature of the studied mixer increased from 1100 to 3800 K. |
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1313 |
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Baubert, J.; Salez, M.; Merkel, H.; Pons, P.; Cherednichenko, S.; Lecomte, B.; Drakinsky, V.; Goltsman, G.; Leone, B. |
Title |
IF gain bandwidth of membrane-based NbN hot electron bolometers for SHAHIRA |
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Journal Article |
Year |
2005 |
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IEEE Trans. Appl. Supercond. |
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IEEE Trans. Appl. Supercond. |
Volume |
15 |
Issue |
2 |
Pages |
507-510 |
Keywords |
NbN HEB mixers, applications |
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SHAHIRA (Submm Heterodyne Array for HIgh-speed Radio Astronomy) is a project supported by the European Space Agency (ESA) and is designed to fly on the SOFIA observatory. A quasi-optic design has been chosen for 2.5/2.7 THz and 4.7 THz, for hydroxyde radical OH, deuterated hydrogen HD and neutral atomic oxygen OI lines observations. Hot electron bolometers (HEBs) have been processed on 1 /spl mu/m thick SiO/sub 2//Si/sub 3/N/sub 4/ stress-less membranes. In this paper we analyse the intermediate frequency (IF) gain bandwidth from the theoretical point of view, and compare it to measurements. |
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1558-2515 |
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1468 |
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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 |
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Journal Article |
Year |
2021 |
Publication |
J. Biomed. Opt. |
Abbreviated Journal |
J. Biomed. Opt. |
Volume |
26 |
Issue |
4 |
Pages |
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Keywords |
medicine; scheimpflug imaging; UVB; confocal microscopy; cornea; optical coherent tomography; rabbit eyes; terahertz radiation |
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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. |
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National Research University Higher School of Economics, Moscow Institute of Electronics and Mathema, Russia |
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1083-3668 |
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PMID:33834684; PMCID:PMC8027227 |
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1258 |
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