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Author Verevkin, A. A.; Ptitsina, N. G.; Smirnov, K. V.; Gol’tsman, G. N.; Gershenzon, E. M.; Ingvesson, K. S. url  doi
openurl 
  Title Direct measurements of energy relaxation times on an AlGaAs/GaAs heterointerface in the range 4.2–50 K Type Journal Article
  Year 1996 Publication JETP Lett. Abbreviated Journal (up) JETP Lett.  
  Volume 64 Issue 5 Pages 404-409  
  Keywords 2DEG, AlGaAs/GaAs heterostructures  
  Abstract The temperature dependence of the energy relaxation time τe (T) of a two-dimensional electron gas at an AlGaAs/GaAs heterointerface is measured under quasiequilibrium conditions in the region of the transition from scattering by acoustic phonons to scattering with the participation of optical phonons. The temperature interval of constant τe, where scattering by the deformation potential predominates, is determined. In the preceding, low-temperature region, where piezoacoustic and deformation-potential-induced scattering processes coexist, τ e decreases slowly with increasing temperature. Optical phonons start to participate in the scattering processes at T∼25 K (the characteristic phonon lifetime was equal to τLOτ4.5 ps). The energy losses calculated from the τe data in a model with an effective nonequilibrium electron temperature agree with the published data obtained under strong heating conditions.  
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  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-3640 ISBN Medium  
  Area Expedition Conference  
  Notes http://jetpletters.ru/ps/981/article_14955.shtml (“Прямые измерения времен энергетической релаксации на гетерогранице AlGaAs/GaAs в диапазоне 4.2 – 50 К”) Approved no  
  Call Number Serial 1608  
Permanent link to this record
 
 
Author Verevkin, A. I.; Ptitsina, N. G.; Chulkova, G. M.; Gol'tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S. url  openurl
  Title Electron energy relaxation in a 2D channel in AlGaAs-GaAs heterostructures under quasiequilibrium conditions at low temperatures Type Journal Article
  Year 1995 Publication JETP Lett. Abbreviated Journal (up) JETP Lett.  
  Volume 61 Issue 7 Pages 591-595  
  Keywords 2DEG, AlGaAs/GaAs heterostructures  
  Abstract The energy relaxation time of 2D electrons, Te, has been measured under quasiequilibrium conditions in AlGaAs—GaAs heterojunctions over the temperature range T= 1.5—20 K. At T> 4 K, Te depends only weakly on the temperature, while at T< 4 K 7;'(T) there is a dependence fr; lNT. A linear dependence 7: 1 (T) in the Bloch—-Grfineisen temperature region (T< 5 K) is unambiguous evidence that a piezoacoustic mechanism of an electron—phonon interaction is predominant in the inelastic scattering of electrons. The values of T6 in this temperature range agree very accurately with theoretical results reported by Karpus [Sov. Phys. Semicond. 22 (1988)]. At higher temperatures, where scat—tering by deformation acoustic phonons becomes substantial, there is a significant discrepancy between the experimental and theoretical re-sults.  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1624  
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Author Verevkin, A.; Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.; Chulkova, G. M.; Smirnov, K. S.; Sobolewski, R. url  openurl
  Title Direct measurements of energy relaxation times in two-dimensional structures under quasi-equilibrium conditions Type Conference Article
  Year 2002 Publication Mater. Sci. Forum Abbreviated Journal (up) Mater. Sci. Forum  
  Volume 384-3 Issue Pages 107-116  
  Keywords 2DEG, AlGaAs/GaAs  
  Abstract A new microwave technique was successfully applied for direct studies of energy relaxation times in two-dimensional AlGaAs/GaAs structures under quasi-equilibrium conditions in the nanosecond and picosecond time scale. We report our results of energy relaxation time measurements in the temperature range 1.6-50 K, in quantum Hall effect regime in magnetic fields up to 4 T.  
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  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference Materials Science Forum  
  Notes Approved no  
  Call Number Serial 1536  
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Author Korneev, A.; Lipatov, A.; Okunev, O.; Chulkova, G.; Smirnov, K.; Gol’tsman, G.; Zhang, J.; Slysz, W.; Verevkin, A.; Sobolewski, R. url  doi
openurl 
  Title GHz counting rate NbN single-photon detector for IR diagnostics of VLSI CMOS circuits Type Journal Article
  Year 2003 Publication Microelectronic Engineering Abbreviated Journal (up) Microelectronic Engineering  
  Volume 69 Issue 2-4 Pages 274-278  
  Keywords NbN SSPD, SNSPD, applications  
  Abstract We present a new, simple to manufacture superconducting single-photon detector operational in the range from ultraviolet to mid-infrared radiation wavelengths. The detector combines GHz counting rate, high quantum efficiency and very low level of dark (false) counts. At 1.3–1.5 μm wavelength range our detector exhibits a quantum efficiency of 5–10%. The detector photoresponse voltage pulse duration was measured to be about 150 ps with jitter of 35 ps and both of them were limited mostly by our measurement equipment. In terms of quantum efficiency, dark counts level, speed of operation the detector surpasses all semiconductor counterparts and was successfully applied for CMOS integrated circuits diagnostics.  
  Address  
  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0167-9317 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1511  
Permanent link to this record
 
 
Author Verevkin, A.; Williams, C.; Gol’tsman, G. N.; Sobolewski, R.; Gilbert, G. url  doi
openurl 
  Title Single-photon superconducting detectors for practical high-speed quantum cryptography Type Miscellaneous
  Year 2001 Publication OFCC/ICQI Abbreviated Journal (up) OFCC/ICQI  
  Volume Issue Pages Pa3  
  Keywords NbN SSPD, SNSPD, QKD, quantum cryptography  
  Abstract We have developed an ultrafast superconducting single-photon detector with negligible dark counting rate. The detector is based on an ultrathin, submicron-wide NbN meander-type stripe and can detect individual photons in the visible to near-infrared wavelength range at a rate of at least 10 Gb/s. The above counting rate allows us to implement the NbN device to unconditionally secret quantum key distRochester, New Yorkribution in a practical, high-speed system using real-time Vernam enciphering.  
  Address Rochester, New York  
  Corporate Author Thesis  
  Publisher Optical Society of America Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference Optical Fiber Communication Conference and International Conference on Quantum Information  
  Notes -- from poster session. Approved no  
  Call Number Serial 1544  
Permanent link to this record
 
 
Author Bell, M.; Sergeev, A.; Mitin, V.; Bird, J.; Verevkin, A.; Gol’tsman, G. url  doi
openurl 
  Title One-dimensional resistive states in quasi-two-dimensional superconductors: Experiment and theory Type Journal Article
  Year 2007 Publication Phys. Rev. B Abbreviated Journal (up) Phys. Rev. B  
  Volume 76 Issue 9 Pages 094521 (1 to 5)  
  Keywords uasi-two-dimensional superconductors, NbN  
  Abstract We investigate competition between one- and two-dimensional topological excitations—phase slips and vortices—in the formation of resistive states in quasi-two-dimensional superconductors in a wide temperature range below the mean-field transition temperature TC0. The widths w=100nm of our ultrathin NbN samples are substantially larger than the Ginzburg-Landau coherence length ξ=4nm, and the fluctuation resistivity above TC0 has a two-dimensional character. However, our data show that the resistivity below TC0 is produced by one-dimensional excitations—thermally activated phase slip strips (PSSs) overlapping the sample cross section. We also determine the scaling phase diagram, which shows that even in wider samples the PSS contribution dominates over vortices in a substantial region of current and/or temperature variations. Measuring the resistivity within 7 orders of magnitude, we find that the quantum phase slips can only be essential below this level.  
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  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1098-0121 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1423  
Permanent link to this record
 
 
Author Zhang, J.; Słysz, W.; Pearlman, A.; Verevkin, A.; Sobolewski, R.; Okunev, O.; Chulkova, G.; Gol’tsman, G. N. url  doi
openurl 
  Title Time delay of resistive-state formation in superconducting stripes excited by single optical photons Type Journal Article
  Year 2003 Publication Phys. Rev. B Abbreviated Journal (up) Phys. Rev. B  
  Volume 67 Issue 13 Pages 132508 (1 to 4)  
  Keywords NbN SSPD, SNSPD  
  Abstract We have observed a 65(±5)-ps time delay in the onset of a resistive-state formation in 10-nm-thick, 130-nm-wide NbN superconducting stripes exposed to single photons. The delay in the photoresponse decreased to zero when the stripe was irradiated by multi-photon (classical) optical pulses. Our NbN structures were kept at 4.2 K, well below the material’s critical temperature, and were illuminated by 100-fs-wide optical pulses. The time-delay phenomenon has been explained within the framework of a model based on photon-induced generation of a hotspot in the superconducting stripe and subsequent, supercurrent-assisted, resistive-state formation across the entire stripe cross section. The measured time delays in both the single-photon and two-photon detection regimes agree well with theoretical predictions of the resistive-state dynamics in one-dimensional superconducting stripes.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0163-1829 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1519  
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Author Verevkin, A. A.; Ptitsina, N. G.; Chulcova, G. M.; Gol'Tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S. url  doi
openurl 
  Title Determination of the limiting mobility of a two-dimensional electron gas in AlxGa1-xAs/GaAs heterostructures and direct measurement of the energy relaxation time Type Journal Article
  Year 1996 Publication Phys. Rev. B Condens. Matter. Abbreviated Journal (up) Phys. Rev. B Condens. Matter.  
  Volume 53 Issue 12 Pages R7592-R7595  
  Keywords 2DEG, AlGaAs/GaAs heterostructures  
  Abstract We present results for a method to measure directly the energy relaxation time (τe) for electrons in a single AlxGa1−xAs/GaAs heterojunction; measurements were performed from 1.6 to 15 K under quasiequilibrium conditions. We find τeαT−1 below 4 K, and τe independent of T above 4 K. We have also measured the energy-loss rate, ⟨Q⟩, by the Shubnikov-de Haas technique, and find ⟨Q⟩α(T3e−T3) for T<~4.2 K; Te is the electron temperature. The values and temperature dependence of τe and ⟨Q⟩ for T<4 K agree with calculations based on piezoelectric and deformation potential acoustic phonon scattering. At 4.2 K, we can also estimate the momentum relaxation time, τm, from our measured τe. This leads to a preliminary estimate of the phonon-limited mobility at 4.2 K of μ=3×107 cm2/Vs (ns=4.2×1011 cm−2), which agrees well with published numerical calculations, as well as with an earlier indirect estimate based on measurements on a sample with much higher mobility.  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0163-1829 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:9982274 Approved no  
  Call Number Serial 1612  
Permanent link to this record
 
 
Author Gol'tsman, G. N.; Korneev, A.; Rubtsova, I.; Milostnaya, I.; Chulkova, G.; Minaeva, O.; Smirnov, K.; Voronov, B.; Słysz, W.; Pearlman, A.; Verevkin, A.; Sobolewski, R. url  doi
openurl 
  Title Ultrafast superconducting single-photon detectors for near-infrared-wavelength quantum communications Type Journal Article
  Year 2005 Publication Phys. Stat. Sol. (C) Abbreviated Journal (up) Phys. Stat. Sol. (C)  
  Volume 2 Issue 5 Pages 1480-1488  
  Keywords NbN SSPD, SNSPD  
  Abstract We present our progress on the research and development of NbN superconducting single‐photon detectors (SSPD's) for ultrafast counting of near‐infrared photons for secure quantum communications. Our SSPD's operate in the quantum detection mode based on the photon‐induced hotspot formation and subsequent development of a transient resistive barrier across an ultrathin and submicron‐width superconducting stripe. The devices are fabricated from 4‐nm‐thick NbN films and kept in the 4.2‐ to 2‐K temperature range. The detector experimental quantum efficiency in the photon‐counting mode reaches above 40% for the visible light and up to 30% in the 1.3‐ to 1.55‐µm wavelength range with dark counts below 0.01 per second. The experimental real‐time counting rate is above 2 GHz and is limited by our readout electronics. The SSPD's timing jitter is below 18 ps, and the best‐measured value of the noise‐equivalent power (NEP) is 5 × 10–21 W/Hz1/2 at 1.3 µm. In terms of quantum efficiency, timing jitter, and maximum counting rate, our NbN SSPD's significantly outperform semiconductor avalanche photodiodes and photomultipliers in the 1.3‐ to 1.55‐µm range.  
  Address  
  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1610-1634 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1479  
Permanent link to this record
 
 
Author Schwaab, G. W.; Hübers, H.-W.; Schubert, J.; Erichsen, Patrik; Gol'tsman, G.; Semenov, A.; Verevkin, A.; Cherednichenko, S.; Gershenzon, E. url  openurl
  Title A high resolution spectrometer for the investigation of molecular structures in the THZ range Type Conference Article
  Year 1999 Publication Proc. 10th Int. Symp. Space Terahertz Technol. Abbreviated Journal (up) Proc. 10th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 530-538  
  Keywords antireflection coatings, dielectric mirrors  
  Abstract A status report on the design study of a novel tunable far-infrared (TuFTR) spectrometer for the investigation of the structure of weakly bound molecular complexes is given. The goal is a sensitive TuFIR spectrometer with full frequency coverage from 1-6 THz. To hit the goal, advanced sources (e.g. p-Ge lasers) and detectors (e.g. superconducting hot electron bolometric (HEB) mixers) shall be employed to extend the technique of cavity ringdown spectroscopy, that is currently used at optical and infrared frequencies to the FIR spectral range. Critical for such a system are high-Q resonators that still allow good optical coupling, and wideband antireflection coatings to increase detector sensitivity and decrease optical path losses. 2 nd order effective media theory and an iterative multilayer algorithm have been employed to design wideband antireflection coatings for dielectrics with large dielectric constants like Ge or Si. Taking into account 6 layers, for Si bandwidths of 100% of the center frequency could be obtained with power reflectivities below 1% for both polarizations simultaneously. Wideband dielectric mirrors including absorption losses were also studied yielding a bandwidth of about 50% with reflectivities larger than 99.5%.  
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  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1577  
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