Now showing items 105-124 of 1046

    • Passive mode locking of 2.09 μm Cr,Tm,Ho:Y3Sc2Al3O12laser using PbS quantum-dot-doped glass 

      Denisov, I. A.; Skoptsov, N. A.; Gaponenko, M. S.; Malyarevich, A. M.; Yumashev, K. V.; Lipovskii, A. A. (Optical Society of America, 2009)
      Passive Q-switched mode locking of a 2.09 μm flashlamp-pumped Cr3+,Tm3+,Ho3+:Y3Sc2Al3O12 laser by use of a phosphate glass doped with PbS quantum dots of 5 nm in radius was demonstrated. Mode-locked pulses of 290 ps in duration and up to 0.5 mJ in energy were registered.
      2012-01-23
    • Passive mode locking of a Tm,Ho:KY(WO4)2 laser around 2 μm 

      Lagatsky, A. A.; Fusari, F.; Calvez, S.; Gupta, J. A.; Kisel, V. E.; Kuleshov, N. V.; Brown, C. T. A.; Dawson, M. D.; Sibbett, W. (Optical Society of America, 2009)
      We report the first demonstration, to our knowledge, of passive mode locking in a Tm3+, Ho3+-codoped KY(WO4)2 laser operating in the 2000-2060 nm spectral region. An InGaAsSb-based quantum well semiconductor saturable absorber mirror is used for the initiation and stabilization of the ultrashort pulse generation. Pulses as short as 3.3 ps were generated at 2057 nm with average ...
      2012-01-23
    • Passive Q-switching of a Tm,Ho:KLu(WO4)2 microchip laser by a Cr:ZnS saturable absorber 

      Serres, Y. M.; Loiko, P. A.; Mateos, X.; Jambunathan, V.; Yasukevich, A. S.; Yumashev, K. V.; Petrov, V.; Griebner, U.; Aguilo, M.; Diaz, F. (Optical Society of America, 2016)
      A diode-pumped Tm;Ho:KLu WO42 microchip laser passively Q-switched with a Cr:ZnS saturable absorber generated an average output power of 131 mW at 2063.6 nm with a slope efficiency of 11% and a Q-switching conversion efficiency of 58%. The pulse characteristics were 14 ns∕9 μJ at a pulse repetition frequency of 14.5 kHz. With higher modulation depth of the saturable absorber, 9 ...
      2016-05-12
    • Passive Q-switching of Yb bulk lasers by a graphene saturable absorber 

      Loiko, P. A.; Serres, J. M.; Mateos, X.; Liu, G.; Zhang, H.; Yasukevich, A. S.; Yumashev, K. V.; Petrov, V.; Griebner, U.; Aguilo, M.; Diaz, F. (Springer, 2016)
      Compact Yb:KLu(WO4)2 and Yb:LuVO4 lasers diode-pumped at 978 nm are passively Q-switched by a single-layer graphene saturable absorber. The Yb:KLu(WO4)2 laser generated 165 ns/0.49 μJ pulses at 1030 nm with 170 mW average output power and 12 % slope efficiency. With the Yb:LuVO4 laser, 152 ns/0.83 μJ pulses were achieved. The output power reached 300 mW at 1024 nm, and the slope ...
      2016-05-11
    • Passively Q-Switched Thulium Microchip Laser 

      Gaponenko, M.; Kuleshov, N.; Südmeyer, T. (2016)
      We present the first passively Q-switched thulium microchip laser. The diode-pumped laser incorporates a Tm:KYW gain medium and an InGaAs semiconductor saturable absorber mirror. The laser emits pulses with a duration of 2.4 ns at a repetition rate of 1.2 MHz with an average output power of 130 mW at a wavelength of 1905 nm. It operates in a fundamental TEM00 mode with M2 < 1.1. ...
      2018-03-06
    • Pathways for photoinduced electron transfer in meso-nitro-phenyl-octaethylporphyrins and their chemical dimers 

      Knyukshto, V.; Zenkevich, E.; Sagun, E.; Shulga, A.; Bachilo, S. (1999)
      The photophysical properties of meso-nitro-phenyl-octaethylporphyrins and their dimers with electron-accepting NO₂ groups in the para-, meta- and ortho-positions of the phenyl ring were studied. For the ortho-NO₂ case in deaerated toluene at 295 K, strong fluorescence quenching is caused by the intramolecular electron transfer from the porphyrin S₁ state in the absence of phenyl ...
      2017-05-25
    • Photoelectric semiconductor converters with a large dynamic range 

      Vorobey, R. I.; Gusev, O. K.; Tyavlovsky, A. K.; Tyavlovsky, K. L.; Svistun, A. I.; Shadurskaya, L. I.; Yarzhembitskaya, N. V.; Kierczynski, K. (2014)
      Photoelectric semiconductor converters with a large dynamic range / R. I. Vorobey [et al.] // Przeglad Elektrotechniczny. – 2014. – Vol. 90, № 5. – PP. 75-78.
      2015-07-06
    • Photoinduced electron transfer dynamics for self-assembled porphyrin arrays in solutions and films 

      Zenkevich, E. I.; Kilin, D. S.; Willert, A.; Bachilo, S. M.; Shulga, A. M.; Rempel, U.; Borczyskowski, C. von (2001)
      Electronic excitation energy deactivation in self-assembled porphyrin triads has been studied by the time correlated single photon counting technique as a function of the solvent polarity (toluene-acetone mixtures), temperature (77-350 K), and mutual spatial arrangement of the donor and acceptor subunits. The donor (Zn-octaethylporphyrin chemical dimer) fluorescence quenching ...
      2017-05-26
    • Photoinduced relaxation processes in self-assembled nanostructures: multiporphyrin complexes and composites "CdSе/ZnS quantum dot-porphyrin" 

      Zenkevich, E. I.; Borczyskowski, C. von (2009)
      Here, we discuss self-assembled multicomponent organic/inorganic nanostructures. Self-assembled multiporphyrin triads were formed via non-covalent interactions of meso-phenyl bridged ZnOEP chemical dimer, (ZnOEP)₂Ph, with dipyridyl substituted tetrapyrrole extra-ligand. In tetrads, the dimer (ZnOEP)₂Ph is covalently linked via 5-mesoposition to additional electron acceptors ...
      2017-05-27
    • Photophysical and photochemical properties of potential porphyrin and chlorin photosensitizers for PDT 

      Zenkevich, E.; Sagun, E.; Knyukshto, V.; Shulga, A.; Mironov, A.; Efremova, O.; Bonnett, R.; Pinda Songca, S.; Kassem, M. (1996)
      Structural and optical properties as well as photophysical and photochemical parameters (excited S₁ and T₁ state lifetimes at 77 K and in the presence of O₂ in solution at 293 K; efficiencies of singlet oxygen, ¹Δg, generation) are presented for porphyrins and chlorins with potential for the PDT of cancer: chlorin p₆ and its trimethyl ester, chlorin e₆ and its Na₃ and K₃ salts, ...
      2017-05-25
    • Pipeline Synthesis and Optimization from Branched Feedback Dataflow Programs 

      Prihozhy, A.; Casale-Brunet, S.; Bezati, E.; Mattavelli, M. (Springer, 2020)
      Large dataflow designs are a result of behavioral specification of modern complex digital systems and/or a result of unfolding and transforming looped and branched programs. Since deep-submicron silicon technology provides large amounts of available resources, pipelining optimization without (or with minimal) resource sharing can give significant advantages in performance. ...
      2021-11-23
    • Plasmonic and Thermooptical Properties of Spherical Metallic Nanoparticles for Their Thermoplasmonic and Photonic Applications 

      Pustovalov, V. K.; Astafyeva, L. G.; Fritzsche, W. (Hindawi Publishing Corporation, 2014)
      Investigations and use of nanoparticles (NPs) as photothermal (PT) agents in laser and optical nanotechnology are fast growing areas of research and applications. The potential benefits of NPs applications include possibility for thermal imaging and treatment of materials containing of NPs, applications of NPs for light-to-thermal energy conversion, in catalysis, laser nanomedicine, ...
      2016-05-11
    • Profit optimization taking into account tax burden and market prices 

      Kochatau, N. V. (СПбГУ ИТМО, 2017)
      The article discusses the idea of search for maximum value profit in conditions of taxation. Using ratio method of estimation of the tax burden on the cash flows of the enterprise managed to construct a mathematical model that allows analyzing the profit by taking the derivative.
      2021-07-20
    • Radiationless intermolecular energy transfer with participation of acceptor excited triplet states 

      Gurinovich, G. P.; Zenkevich, E. I.; Sagun, E. I. (1982)
      Radiationless energy transfer between like and unlike molecules has been experimentally studied under conditions where acceptor molecules have been excited to the triplet state. Homogeneous singlet—triplet—triplet migration has been discovered in higbly concentrated chlorophyll “a” and pheophytin “a” solutions in castor oil at 183 K by measuring the variation of pigment relative ...
      2017-05-18
    • Regularities of intermolecular interactions and energy transfer in mixed associates of chlorophyll and its analogs 

      Zenkevich, E. I.; Losev, A. P.; Kochubeev, G. A.; Gurinovich, G. P. (Elsevier Scientific Publishing Company, 1978)
      Regularities of intermolecular interactions and energy transfer in mixed associates of chlorophyll and its analogs / E. I. Zenkevich [et al.] // Journal of Molecular Structure. – 1978. Vol. 45. – P. 423-436.
      2017-05-18
    • Resonance Raman spectra interpretation by molecular coherent state representation 

      Trifonov, N. (1992)
      In this paper the problem of exact summation over vibrational states of intermediate electronic level excited by resonance Raman scattering in a molecular system with an arbitrary number of vibrational modes is solved with the help of the coherent state representation. For matrix elements of the resonance Raman (RR) amplitude the expressions in the form of an integral and multiple ...
      2014-03-28
    • Resonant Raman Scattering of ZnS, ZnO, and ZnS/ZnO Core/shell quantum dots 

      Milekhin, A. G.; Yeryukov, N. A.; Sveshnikova, L. L.; Duda, T. A.; Himcinschi, C.; Zenkevich, E. I.; Zahn, D. R. T. (2012)
      Resonant Raman scattering by optical phonon modes as well as their overtones was investigated in ZnS and ZnO quantum dots grown by the Langmuir–Blodgett technique. The in situ formation of ZnS/ZnO core/shell quantum dots was monitored by Raman spectroscopy during laser illumination.
      2017-05-27
    • Resonant Raman studies of compositional and size dispersion of CdS₁₋ₓSeₓ nanocrystals in a glass matrix 

      Azhniuk, Yu. M; Milekhin, A. G.; Gomonnai, A. V.; Lopushansky, V. V.; Yukhymchuk, V. O.; Schulze, S.; Zenkevich, E. I.; Zahn, D. R. T. (2004)
      Resonant Raman scattering spectra of glass-embedded CdS₁₋ₓSeₓ nanocrystals are measured and complemented with TEM and optical absorption as well as photoluminescence data. The selectivity of the resonant Raman process not only for the size, but also for the composition of nanocrystals within the ensemble, is directly observed in the dependence of phonon band frequency, linewidth ...
      2017-05-27
    • Risk-management of investment projects 

      Savko, T.; Temichev, A. (КНИТУ, 2012)
      The article is devoted to the questions of risk management. The necessity of investment projects risk analysis is conditioned by the fact, that cash flows, built during the investment project creation, apply to future periods, and, therefore, have predictive character. Hence, the importance of investment projects risk-management is increasing, as just comprehensive risk management ...
      2018-04-11
    • A Ritz's method based solution for the contact problem of a deformable rectangular plate on an elastic quarter-space 

      Guenfoud, S.; Bosakov, S. V.; Laefer, D. F. (Elsevier, 2010)
      In this article, Ritz’s method is used to calculate with unprecedented accuracy the displacements related to a deformable rectangular plate resting on the surface of an elastic quarter-space. To achieve this required three basic steps. The first step involved the study of Green’s function describing the vertical displacements of the surface of an elastic quarter-space due to ...
      2018-09-13