Records |
Author |
Iomdina, E. N.; Goltsman, G. N.; Seliverstov, S. V.; Sianosyan, A. A.; Teplyakova, K. O.; Rusova, A. A. |
Title |
Study of transmittance and reflectance spectra of the cornea and the sclera in the THz frequency range |
Type |
Journal Article |
Year |
2016 |
Publication |
J. Biomed. Opt. |
Abbreviated Journal |
J. Biomed. Opt. |
Volume |
21 |
Issue |
9 |
Pages |
97002 (1 to 5) |
Keywords |
BWO, IMPATT diode, Schottky diode, medicine, animals, cornea, physiology, humans, rabbits, sclera diagnostic imaging, physiology |
Abstract |
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. Adequate control of corneal and scleral hydration is very important for early diagnosis of a variety of eye diseases, stating indications for and contraindications against keratorefractive surgeries and the choice of contact lens correction solutions. THz systems of creating images in reflected beams are likely to become ideal instruments of noninvasive control of corneal and scleral hydration degrees. This paper reports on the results of a study involving transmittance and reflectance spectra for the cornea and the sclera of rabbit and human eyes, as well as those of the rabbit eye, in the frequency range of 0.13 to 0.32 THz. The dependence of the reflectance coefficient of these tissues on water mass percentage content was determined. The experiments were performed on three corneas, three rabbit scleras, two rabbit eyes, and three human scleras. The preliminary results demonstrate that the proposed technique, based on the use of a continuous THz radiation, may be utilized to create a device for noninvasive control of corneal and scleral hydration, which has clear potential of broad practical application. |
Address |
Moscow State Pedagogical University, Department of Physics, 29 Malaya Pirogovskaya Street, Moscow 119435, Russia |
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English |
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1083-3668 |
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PMID:27626901 |
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1335 |
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Author |
Gershenzon, E. M.; Gol'tsman, G. N.; Elant'ev, A. I.; Karasik, B. S.; Potoskuev, S. E. |
Title |
Intense electromagnetic radiation heating of superconductor electrons in resistive state |
Type |
Journal Article |
Year |
1988 |
Publication |
Fizika Nizkikh Temperatur |
Abbreviated Journal |
Fizika Nizkikh Temperatur |
Volume |
14 |
Issue |
7 |
Pages |
753-763 |
Keywords |
Nb HEB |
Abstract |
An experimental study is made of the effect of intense radiation in the millimeter and submillimeter ranges on thin and narrow Nb films in the resistive state. It is found that the excess resistance resulting from radiation and the dependence of its relaxation time on radiation intensity and transport current can be explained in terms of the effect of electron heating. Quantitative agreement is obtained between the experimental data and a homogeneous electron heating model. |
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1697 |
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Cherednichenko, S.; Kroug, M.; Yagoubov, P.; Merkel, H.; Kollberg, E.; Yngvesson, K. S.; Voronov, B.; Gol’tsman, G. |
Title |
IF bandwidth of phonon cooled HEB mixers made from NbN films on MgO substrates |
Type |
Conference Article |
Year |
2000 |
Publication |
Proc. 11th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 11th Int. Symp. Space Terahertz Technol. |
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Issue |
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Pages |
219-227 |
Keywords |
NbN HEB mixers, cinversion gain bandwidth, IF bandwidth |
Abstract |
An investigation of gain and noise bandwidth of phonon-cooled hot-electron bolometric (HEB) mixers is presented. The radiation coupling to the mixers is quasioptical through either a spiral or twin-slot antenna. A maximum gain bandwidth of 4.8 GHz is obtained for mixers based on a 3.5 nm thin NbN film with Tc= 10 K. The noise bandwidth is 5.6 GHz, at the moment limited by parasitic elements in the, device mount fixture. At 0.65 THz the DSB receiver noise temperature is 700-800 К in the IF band 1-2 GHz, and 1150-2700 К in the band 3.5-7 GHz. |
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1557 |
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Author |
Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G. |
Title |
Population and lifetime of excited states of shallow impurities in Ge |
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Journal Article |
Year |
1979 |
Publication |
Sov. Phys. JETP |
Abbreviated Journal |
Sov. Phys. JETP |
Volume |
49 |
Issue |
2 |
Pages |
355-362 |
Keywords |
Ge, photothermal ionization, shallow impurities |
Abstract |
An investigation was made of the dependences of the intensities of photothermal ionization lines of excited states of shallow impurities in Ge on the intensity of impurity-absorbed background radiation and on temperature. The results obtained were used to find the density and lifetime of carriers of lower excited states of the impurity centers. The lifetimes of the excited states of donors in Ge were 10-~-10-" sec and the lifetime of the lower excited state of acceptors was -lo-' sec. In the presence of background radiation the population of the excited states was very different from the equilibrium value and, in particular, a population inversion of the 2pk, state relative to the 3p0 and 3s states was observed. |
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1719 |
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Smirnov, K. V.; Vachtomin, Y. B.; Ozhegov, R. V.; Pentin, I. V.; Slivinskaya, E. V.; Korneev, A. A.; Goltsman, G. N. |
Title |
Fiber coupled single photon receivers based on superconducting detectors for quantum communications and quantum cryptography |
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Conference Article |
Year |
2008 |
Publication |
Proc. SPIE |
Abbreviated Journal |
Proc. SPIE |
Volume |
7138 |
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Pages |
713827 (1 to 6) |
Keywords |
SSPD, SNSPD, superconducting single photon detector, ultra-thin superconducting films, optical fiber coupling, ready to use receiver |
Abstract |
At present superconducting detectors become increasingly attractive for various practical applications. In this paper we present results on the depelopment of fiber coupled receiver systems for the registration of IR single photons, optimized for telecommunication and quantum-cryptography. These receiver systems were developed on the basis of superconducting single photon detectors (SSPD) of VIS and IR wavelength ranges. The core of the SSPD is a narrow ( 100 nm) and long ( 0,5 mm) strip in the form of a meander which is patterned from a 4-nm-thick NbN film (TC=10-11 K, jC= 5-7•106 A/cm2); the sensitive area dimensions are 10×10 μm2. The main problem to be solved while the receiver system development was optical coupling of a single-mode fiber (9 microns in diameter) with the SSPD sensitive area. Characteristics of the developed system at the optical input are as follows: quantum efficiency >10 % (at 1.3 μm), >4 % (at 1.55 μm); dark counts rate ≤1 s-1; duration of voltage pulse ≤5 ns; jitter ≤40 ps. The receiver systems have either one or two identical channels (for the case of carrying out correlation measurements) and are made as an insert in a helium storage Dewar. |
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Spie |
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Tománek, P.; Senderáková, D.; Hrabovský, M. |
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1405 |
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