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Author Morozov, P.; Lukina, M.; Shirmanova, M.; Divochiy, A.; Dudenkova, V.; Gol'tsman, G. N.; Becker, W.; Shcheslavskiy, V. I. url  doi
openurl 
  Title Singlet oxygen phosphorescence imaging by superconducting single-photon detector and time-correlated single-photon counting Type Journal Article
  Year 2021 Publication Opt. Lett. Abbreviated Journal Opt. Lett.  
  Volume 46 Issue 6 Pages 1217-1220  
  Keywords SSPD, SNSPD, applications  
  Abstract This Letter presents, to the best of our knowledge, a novel optical configuration for direct time-resolved measurements of luminescence from singlet oxygen, both in solutions and from cultured cells on photodynamic therapy. The system is based on the superconducting single-photon detector, coupled to the confocal scanner that is modified for the near-infrared measurements. The recording of a phosphorescence signal from singlet oxygen at 1270 nm has been done using time-correlated single-photon counting. The performance of the system is verified by measuring phosphorescence from singlet oxygen generated by the photosensitizers commonly used in photodynamic therapy: methylene blue and chlorin e6. The described system can be easily upgraded to the configuration when both phosphorescence from singlet oxygen and fluorescence from the cells can be detected in the imaging mode. Thus, co-localization of the signal from singlet oxygen with the areas inside the cells can be done.  
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  Series Volume Series Issue Edition  
  ISSN 0146-9592 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:33720151 Approved no  
  Call Number Serial 1221  
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Author Arutyunov, K. Y.; Ramos-Alvarez, A.; Semenov, A. V.; Korneeva, Y. P.; An, P. P.; Korneev, A. A.; Murphy, A.; Bezryadin, A.; Gol'tsman, G. N. url  doi
openurl 
  Title Superconductivity in highly disordered NbN nanowires Type Journal Article
  Year 2016 Publication Nanotechnol. Abbreviated Journal Nanotechnol.  
  Volume 27 Issue 47 Pages 47lt02 (1 to 8)  
  Keywords NbN nanowires  
  Abstract The topic of superconductivity in strongly disordered materials has attracted significant attention. These materials appear to be rather promising for fabrication of various nanoscale devices such as bolometers and transition edge sensors of electromagnetic radiation. The vividly debated subject of intrinsic spatial inhomogeneity responsible for the non-Bardeen-Cooper-Schrieffer relation between the superconducting gap and the pairing potential is crucial both for understanding the fundamental issues of superconductivity in highly disordered superconductors, and for the operation of corresponding nanoelectronic devices. Here we report an experimental study of the electron transport properties of narrow NbN nanowires with effective cross sections of the order of the debated inhomogeneity scales. The temperature dependence of the critical current follows the textbook Ginzburg-Landau prediction for the quasi-one-dimensional superconducting channel I c approximately (1-T/T c)(3/2). We find that conventional models based on the the phase slip mechanism provide reasonable fits for the shape of R(T) transitions. Better agreement with R(T) data can be achieved assuming the existence of short 'weak links' with slightly reduced local critical temperature T c. Hence, one may conclude that an 'exotic' intrinsic electronic inhomogeneity either does not exist in our structures, or, if it does exist, it does not affect their resistive state properties, or does not provide any specific impact distinguishable from conventional weak links.  
  Address National Research University Higher School of Economics, Moscow Institute of Electronics and Mathematics,109028, Moscow, Russia. P L Kapitza Institute for Physical Problems RAS, Moscow, 119334, Russia  
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  Series Volume Series Issue Edition  
  ISSN 0957-4484 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:27782000 Approved no  
  Call Number Serial 1332  
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Author Nebosis, R. S.; Heusinger, M. A.; Semenov, A. D.; Lang, P. T.; Schatz, W.; Steinke, R.; Renk, K. F.; Gol'tsman, G. N.; Karasik, B. S.; Gershenzon, E. M. url  doi
openurl 
  Title Ultrafast photoresponse of an YBa2Cu3O7-δ film to far-infrared radiation pulses Type Journal Article
  Year 1993 Publication Opt. Lett. Abbreviated Journal Opt. Lett.  
  Volume 18 Issue 2 Pages 96-97  
  Keywords YBCO HTS detectors  
  Abstract We report the observation of an ultrafast photoresponse of a high-T(c), film to far-infrared radiation pulses. The response of a sample, consisting of a current-carrying structured YBa(2)Cu(3)O(7-delta) film cooled to liquid-nitrogen temperature, was studied by use of ultrashort laser pulses from an optically pumped far-infrared laser in the frequency range from 0.7 to 7 THz. We found that the response time was limited by the time resolution, 120 ps, of our electronic registration equipment.  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0146-9592 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:19802049 Approved no  
  Call Number Serial 1660  
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Author Mohan, N.; Minaeva, O.; Gol'tsman, G. N.; Nasr, M. B.; Saleh, B. E.; Sergienko, A. V.; Teich, M. C. url  doi
openurl 
  Title Photon-counting optical coherence-domain reflectometry using superconducting single-photon detectors Type Journal Article
  Year 2008 Publication Opt. Express Abbreviated Journal Opt. Express  
  Volume 16 Issue 22 Pages 18118-18130  
  Keywords SSPD, SNSPD  
  Abstract We consider the use of single-photon counting detectors in coherence-domain imaging. Detectors operated in this mode exhibit reduced noise, which leads to increased sensitivity for weak light sources and weakly reflecting samples. In particular, we experimentally demonstrate the possibility of using superconducting single-photon detectors (SSPDs) for optical coherence-domain reflectometry (OCDR). These detectors are sensitive over the full spectral range that is useful for carrying out such imaging in biological samples. With counting rates as high as 100 MHz, SSPDs also offer a high rate of data acquisition if the light flux is sufficient.  
  Address Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA. nm82@bu.edu  
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  Series Volume Series Issue Edition  
  ISSN 1094-4087 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:18958090 Approved no  
  Call Number Serial 1407  
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Author Gol'tsman, G. N.; Gusinskii, E. N.; Malyavkin, A. V.; Ptitsina, N. G.; Selevko, A. G.; Edel'shtein, V. M. url  openurl
  Title The excitonic Zeeman effect in uniaxially-strained germanium Type Journal Article
  Year 1987 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP  
  Volume 65 Issue 6 Pages 1233-1241  
  Keywords Ge, Zeeman effect  
  Abstract We have carried out a high-resolution spectroscopic study of the absorption of submillimeter radiation by free excitons in germanium compressed along the [ 1 11 ] axis in a magnetic field parallel to the compression axis. In particular, we studied the splitting of the 1s- 2p transition in fields up to 6 kOe at T = 1.6 K, and observed a complex pattern in the Zeeman splitting which we believe is related to the effect of thermal motion of the excitons in a magnetic field on their internal structure (the magneto-Stark effect). The calculated submillimeter spectrum of excitons agrees with the experimental data. We predict that in a magnetic field the energy of the 2p, term is a minimum at a finite value of the exciton momentum perpendicular to the field-that is, the energy minimum forms a ring in momentum space. It follows that the density of states for this term must be a nonmonotonic function of the energy. A theory is developed of analogous phenomena in positronium.  
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  Notes Approved no  
  Call Number Serial 1705  
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.; Riger, E. R. url  openurl
  Title Effect of electron-electron collisions on the trapping of free carriers by shallow impurity centers in germanium Type Journal Article
  Year 1986 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP  
  Volume 64 Issue 4 Pages 889-897  
  Keywords Ge, trapping of free carriers  
  Abstract Cascade Auger recombination of free carriers on shallow impurities in Ge is investigated under quasi-equilibrium conditions (T= 2-12 K) and in impurity breakdown. The Auger capture cross sections are found to be a,= 5. 10-l9 T-'n cm2 for donors and uip= 7- T-5p cm2 for acceptors. It is shown that in an isotropic semiconductor (p-Ge) ui is well described by the cascade-capture theory that takes into account only electron-electron collisions. In an anisotropic semiconductor ui is considerably larger (n-Ge, strongly uniaxially compressedp-Ge). Under impurity breakdown conditions the electron-electron collisions determine the lifetimes of the free carriers only in samples with appreciable density of the compensating impurity (Nk loi3 cmP3).  
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  Notes Approved no  
  Call Number Serial 1707  
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Author Gershenzon, E. M.; Gershenzon, M. E.; Gol'tsman, G. N.; Semenov, A. D.; Sergeev, A. V. url  openurl
  Title Heating of electrons in a superconductor in the resistive state by electromagnetic radiation Type Journal Article
  Year 1984 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP  
  Volume 59 Issue 2 Pages 442-450  
  Keywords Nb HEB  
  Abstract The effect of heating of electrons relative to phonons is observed and investigated in a superconducting film that is made resistive by current and by an external magnetic field. The effect is manifested by an increase of the film resistance under the influence of the electromagnetic radiation, and is not selective in the frequency band 10^10-10^15 Hz. The independence of the effect of frequency under conditions of strong scattering by static defects is attributed to the decisive role of electron-electron collisions in the distribution function. The experimentally obtained characteristic time of resistance variation near the superconducting transition corresponds to the relaxation time of the order parameter, while at lower temperatures and fields it corresponds to the time of the inelastic electron-phonon interaction.  
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  Notes Approved no  
  Call Number RPLAB @ phisix @ Serial 983  
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Multanovskii, V. V.; Ptitsina, N. G. url  openurl
  Title Kinetics of electron and hole binding into excitons in germanium Type Journal Article
  Year 1983 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP  
  Volume 57 Issue 2 Pages 369-376  
  Keywords Ge, electron and hole binding  
  Abstract The kinetics of binding of free carriers'into excitons under stationary and nonstationary conditions is studied by investigating the submillimeter photoconductivity of Ge in a wide range of temperatures and of excitation levels. It is shown that the absolute values and the temperature dependence of the binding cross section (o- T-'.' ) can be satisfactorily described by the cascade recombination theory. The value of o and its temperature dependence differ significantly from the cross sections, measured in the same manner, for capture by attracting small impurities. Under nonstationary conditions, just as in the case of recombination with shallow impurities, a signifi- cant role is played by the sticking of the carriers in highly excited states.  
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  Notes Approved no  
  Call Number Serial 1711  
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Multanovskii, V. V.; Ptitsyna, N. G. url  openurl
  Title Capture of photoexcited carriers by shallow impurity centers in germanium Type Journal Article
  Year 1979 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP  
  Volume 50 Issue 4 Pages 728-734  
  Keywords Ge, photoexcited carriers, shallow impurity centers  
  Abstract Measurements were made of the lifetimes rf of free carriers and the relaxation time 7, of the submillimeter impurity photoconductivity when carriers are captured by attracting shallow donors and acceptom in Ge. It is nod that in samples with capture-center concentration N,Z 10"cm-' the relaxation time 7, greatly exceeds rf in the temperature range 4.2-12 K. The measured values of 7,- are compared with the calculation of cascade recombination by the classical model. To evaluate the data on T,, the distinguishing features of this model are considered for the nonstationary case. The substantial difference betweea the values of rf and T, is attributed to re-emission of the carriers from the excited states of the shallow impurities.  
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  Notes Approved no  
  Call Number Serial 1720  
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G. url  openurl
  Title Population and lifetime of excited states of shallow impurities in Ge Type 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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  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1719  
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