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Author Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.; Riger, E. R.
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 Gol'tsman, G. N.; Gusinskii, E. N.; Malyavkin, A. V.; Ptitsina, N. G.; Selevko, A. G.; Edel'shtein, V. M.
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.; Gogidze, I. G.; Goltsman, G. N.; Semenov, A. D.; Sergeev, A. V.
Title Picosecond response on optical-range emission in thin YBaCuO films Type Journal Article
Year 1991 Publication Pisma v Zhurnal Tekhnicheskoi Fiziki Abbreviated Journal Pisma v Zhurnal Tekhnicheskoi Fiziki
Volume 17 Issue 22 Pages 6-10
Keywords YBCO HTS detectors
Abstract Целью настоящей работы является целенаправленный поиск пико-секундного отклика на оптическое излучение выяснение оптималь­ных условий его наблюдения, а также сравнение характеристик не­равновесных эффектов в оптическом и субмиллиметровом диапазонах.
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Publisher Place of Publication Editor
Language Russian Summary Language Original Title
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Notes Approved no
Call Number Serial 1684
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Author Sergeev, A. V.; Semenov, A. D.; Kouminov, P.; Trifonov, V.; Goghidze, I. G.; Karasik, B. S.; Gol’tsman, G. N.; Gershenzon, E. M.
Title Transparency of a YBa2Cu3O7-film/substrate interface for thermal phonons measured by means of voltage response to radiation Type Journal Article
Year 1994 Publication Phys. Rev. B Condens. Matter. Abbreviated Journal Phys. Rev. B Condens. Matter.
Volume 49 Issue 13 Pages 9091-9096
Keywords YBCO films
Abstract The transparency of a film/substrate interface for thermal phonons was investigated for YBa2Cu3O7 thin films deposited on MgO, Al2O3, LaAlO3, NdGaO3, and ZrO2 substrates. Both voltage response to pulsed-visible and to continuously modulated far-infrared radiation show two regimes of heat escape from the film to the substrate. That one dominated by the thermal boundary resistance at the film/substrate interface provides an initial exponential decay of the response. The other one prevailing at longer times or smaller modulation frequencies causes much slower decay and is governed by phonon diffusion in the substrate. The transparency of the boundary for phonons incident from the film on the substrate and also from the substrate on the film was determined separately from the characteristic time of the exponential decay and from the time at which one regime was changed to the other. Taking into account the specific heat of optical phonons and the temperature dependence of the group velocity of acoustic phonons, we show that the body of experimental data agrees with acoustic mismatch theory rather than with the model that assumes strong diffusive scattering of phonons at the interface.
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ISSN 0163-1829 ISBN Medium
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Notes PMID:10009690 Approved no
Call Number Serial 1648
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Author Nasr, M. B.; Minaeva, O.; Goltsman, G. N.; Sergienko, A. V.; Saleh, B. E.; Teich, M. C.
Title Submicron axial resolution in an ultrabroadband two-photon interferometer using superconducting single-photon detectors Type Journal Article
Year 2008 Publication Opt. Express Abbreviated Journal Opt. Express
Volume 16 Issue 19 Pages 15104-15108
Keywords SSPD, SNSPD
Abstract We generate ultrabroadband biphotons via the process of spontaneous parametric down-conversion in a quasi-phase-matched nonlinear grating that has a linearly chirped poling period. Using these biphotons in conjunction with superconducting single-photon detectors (SSPDs), we measure the narrowest Hong-Ou-Mandel dip to date in a two-photon interferometer, having a full width at half maximum (FWHM) of approximately 5.7 fsec. This FWHM corresponds to a quantum optical coherence tomography (QOCT) axial resolution of 0.85 µm. Our results indicate that a high flux of nonoverlapping biphotons may be generated, as required in many applications of nonclassical light.
Address Departments of Electrical & Computer Engineering and Physics, Quantum Imaging Laboratory, Boston University, Boston, MA 02215, USA. boshra@bu.edu
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Publisher Place of Publication Editor
Language English Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 1094-4087 ISBN Medium
Area Expedition Conference
Notes PMID:18795048 Approved no
Call Number Serial 1408
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