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Author | Seliverstov, S.; Maslennikov, S.; Ryabchun, S.; Finkel, M.; Klapwijk, T. M.; Kaurova, N.; Vachtomin, Yu.; Smirnov, K.; Voronov, B.; Goltsman, G. | ||||
Title | Fast and sensitive terahertz direct detector based on superconducting antenna-coupled hot electron bolometer | Type | Journal Article | ||
Year | 2015 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
Volume | 25 | Issue | 3 | Pages | 2300304 |
Keywords | HEB detector responsivity, HEB model, numerical calculations, numerical model | ||||
Abstract | We characterize superconducting antenna-coupled hot-electron bolometers for direct detection of terahertz radiation operating at a temperature of 9.0 K. The estimated value of responsivity obtained from lumped-element theory is strongly different from the measured one. A numerical calculation of the detector responsivity is developed, using the Euler method, applied to the system of heat balance equations written in recurrent form. This distributed element model takes into account the effect of nonuniform heating of the detector along its length and provides results that are in better agreement with the experiment. At a signal frequency of 2.5 THz, the measured value of the optical detector noise equivalent power is 2.0 × 10-13 W · Hz-0.5. The value of the bolometer time constant is 35 ps. The corresponding energy resolution is about 3 aJ. This detector has a sensitivity similar to that of the state-of-the-art sub-millimeter detectors operating at accessible cryogenic temperatures, but with a response time several orders of magnitude shorter. | ||||
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Notes | Approved | no | |||
Call Number | Serial | 953 | |||
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Author | Tuchak, A. N.; Gol’tsman, G. N.; Kitaeva, G. K.; Penin, A. N.; Seliverstov, S. V.; Finkel, M. I.; Shepelev, A. V.; Yakunin, P. V. | ||||
Title | Generation of nanosecond terahertz pulses by the optical rectification method | Type | Journal Article | ||
Year | 2012 | Publication | JETP Lett. | Abbreviated Journal | JETP Lett. |
Volume | 96 | Issue | 2 | Pages | 94-97 |
Keywords | optical rectification, lithium niobate crystal | ||||
Abstract | The possibility of the generation of quasi-cw terahertz radiation by the optical rectification method for broad-band Fourier unlimited nanosecond laser pulses has been experimentally demonstrated. The broadband radiation of a LiF dye-center laser is used as a pump source of a nonlinear optical oscillator. The energy efficiency of terahertz optical frequency conversion in a periodically polarized lithium niobate crystal is 4 × 10−9 at a pump power density of 7 MW/cm2. | ||||
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Series Volume | Series Issue | Edition | |||
ISSN | 0021-3640 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | no | |||
Call Number | Serial | 1377 | |||
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Author | Angeluts, A. A.; Bezotosnyi, V. V.; Cheshev, E. A.; Goltsman, G. N.; Finkel, M. I.; Seliverstov, S. V.; Evdokimov, M. N.; Gorbunkov, M. V.; Kitaeva, G. Kh.; Koromyslov, A. L.; Kostryukov, P. V.; Krivonos, M. S.; Lobanov, Yu. V.; Shkurinov, A. P.; Sarkisov, S. Yu.; Tunkin, V. G. | ||||
Title | Compact 1.64 THz source based on a dual-wavelength diode end-pumped Nd:YLF laser with a nearly semiconfocal cavity | Type | Journal Article | ||
Year | 2014 | Publication | Laser Phys. Lett. | Abbreviated Journal | |
Volume | 11 | Issue | 1 | Pages | 015004 (1 to 4) |
Keywords | HEB applications, HEB detector applications, short THz pulses detection | ||||
Abstract | We describe a compact dual-wavelength (1.047 and 1.053 μm) diode end-pumped Q-switched Nd:YLE laser source which has a number of applications in demand. In order to achieve its dual-wavelength operation it is suggested for the first time to use essentially nonmonotonous dependences of the threshold pump powers at these wavelengths on the cavity length in the region of the cavity semiconfocal configuration under a radius of the pump beam smaller than the radius of the zero Gaussian mode. Here we demonstrate one of the most interesting applications for this laser: difference frequency generation in a GaSe crystal at a frequency of 1.64 THz. A superconducting hot-electron bolometer is used to detect the THz power generated and to measure its pulse characteristics. | ||||
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Notes | Approved | no | |||
Call Number | Serial | 1076 | |||
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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 | |||
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Author | Shurakov, A.; Seliverstov, S.; Kaurova, N.; Finkel, M.; Voronov, B.; Goltsman, G. | ||||
Title | Input bandwidth of hot electron bolometer with spiral antenna | Type | Journal Article | ||
Year | 2012 | Publication | IEEE Trans. THz Sci. Technol. | Abbreviated Journal | IEEE Trans. THz Sci. Technol. |
Volume | 2 | Issue | 4 | Pages | 400-405 |
Keywords | NbN HEB bolometers bandwidth, log-spiral antenna | ||||
Abstract | We report the results of our study of the input bandwidth of hot electron bolometers (HEB) embedded into the planar log-spiral antenna. The sensitive element is made of the ultrathin superconducting NbN film patterned as a bridge at the feed of the antenna. The contacts between the antenna and a sensitive element are made from in situ deposited gold (i.e., deposited over NbN film without breaking vacuum), which gives high quality contacts and makes the response of the HEB at higher frequencies less affected by the RF loss. An accurate experimental spectroscopic procedure is demonstrated that leads to the confirmation of the wide ( 8 THz) bandwidth in this antenna coupled device. | ||||
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ISSN | 2156-342X | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | no | |||
Call Number | Serial | 1161 | |||
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Author | Tretyakov, I. V.; Finkel, M. I.; Ryabchun, S. A.; Kardakova, A. I.; Seliverstov, S. V.; Petrenko, D. V.; Goltsman, G. N. | ||||
Title | Hot-electron bolometer mixers with in situ contacts | Type | Journal Article | ||
Year | 2014 | Publication | Radiophys. Quant. Electron. | Abbreviated Journal | Radiophys. Quant. Electron. |
Volume | 56 | Issue | 8-9 | Pages | 591-598 |
Keywords | HEB mixers | ||||
Abstract | We report on the latest achievements in the development of superconducting hot-electron bolometer (HEB) mixers for terahertz superheterodyne receivers. We consider application ranges of such receivers and requirements for the basic characteristics of the mixers. Main features of the mixers, such as noise temperature, gain bandwidth, noise bandwidth, and required local-oscillator power, have been improved significantly over the past few years due to intense research work, both in terms of the element fabrication quality and in terms of understanding of the physics of the processes occurring in the HEB mixers. Contacts between the superconducting bridge and the planar antenna play a key role in the mixer operation. Improvement of the quality of the contacts leads simultaneously to a decrease in the noise temperature and an increase in the gain bandwidth of a mixer. | ||||
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ISSN | 0033-8443 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | no | |||
Call Number | Serial | 1170 | |||
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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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ISSN | 2211-5463 | ISBN | Medium | ||
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Notes | Poster P-01-040 | Approved | no | ||
Call Number | Serial | 1276 | |||
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Author | Iomdina, E. N.; Seliverstov, S. V.; Sianosyan, A. A.; Teplyakova, K. O.; Rusova, A. A.; Goltsman, G. N. | ||||
Title | Terahertz scanning for evaluation of corneal and scleral hydration | Type | Journal Article | ||
Year | 2018 | Publication | Sovremennye tehnologii v medicine | Abbreviated Journal | STM |
Volume | 10 | Issue | 4 | Pages | 143-149 |
Keywords | BWO; Golay cell; medicine; cornea; sclera; THz radiation; corneal hydration; backward-wave oscillator; avalanche transit-time diode; IMPATT diode | ||||
Abstract | The aim of the investigation was to study the prospects of using continuous THz scanning of the cornea and the sclera to determine water concentration in these tissues and on the basis of the obtained data to develop the experimental installation for monitoring corneal and scleral hydration degree.Materials and Methods. To evaluate corneal and scleral transmittance and reflectance spectra in the THz range, the developed experimental installations were used to study 3 rabbit corneas and 3 scleras, 2 whole rabbit eyes, and 3 human scleras. Besides, two rabbit eyes were studied in vivo prior to keratorefractive surgery as well as 10 and 21 days following the surgery (LASIK).Results. There have been created novel experimental installations enabling in vitro evaluation of frequency dependence of corneal and scleral transmittance coefficients and reflectance coefficients on water percentage in the THz range. Decrease in corneal water content by 1% was found to lead to reliably established decrease in the reflected signal by 13%. The reflectance spectrum of the whole rabbit eye was measured in the range of 0.13–0.32 THz. The study revealed the differences between the indices of rabbit cornea and sclera, as well as rabbit and human sclera. There was developed a laboratory model of the installation for in vivo evaluation of corneal and scleral hydration using THz radiation.Conclusion. The preliminary findings show that the proposed technique based on the use of continuous THz radiation can be employed to create a device for noninvasive control of corneal and scleral hydration. | ||||
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Notes | Approved | no | |||
Call Number | Serial | 1315 | |||
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Author | Seliverstov, S. V.; Anfertyev, V. A.; Tretyakov, I. V.; Ozheredov, I. A.; Solyankin, P. M.; Revin, L. S.; Vaks, V. L.; Rusova, A. A.; Goltsman, G. N.; Shkurinov, A. P. | ||||
Title | Terahertz heterodyne receiver with an electron-heating mixer and a heterodyne based on the quantum-cascade laser | Type | Journal Article | ||
Year | 2017 | Publication | Radiophys. Quant. Electron. | Abbreviated Journal | Radiophys. Quant. Electron. |
Volume | 60 | Issue | 7 | Pages | 518-524 |
Keywords | NbN HEB mixer, QCL | ||||
Abstract | We study characteristics of the laboratory prototype of a terahertz heterodyne receiver with an electron-heating mixer and a heterodyne based on the quantum-cascade laser. The results obtained demonstrate the possibility to use this receiver as a basis for creation of a high-sensitivity terahertz spectrometer, which can be used in many basic and practical applications. A significant advantage of this receiver will be the possibility of placing the mixer and heterodyne in the same cryostat, which will reduce the device dimensions considerably. The obtained experimental results are analyzed, and methods of optimizing the parameters of the receiver are proposed. | ||||
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ISSN | 0033-8443 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | no | |||
Call Number | Serial | 1322 | |||
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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 | 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 | ||
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Notes | Approved | no | |||
Call Number | Serial | 1333 | |||
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