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Proceedings Paper

Ultrafast relaxation in Y-Ba-Cu-O and Ni thin films studied by nonlinear spectroscopy technique
Author(s): Victor N. Bagratashvili; Vladimir A. Lobastov; Alexander N. Zherikhin; V. M. Petnikova; Vladimir V. Shuvalov
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Paper Abstract

By picosecond spectrometer with two tunable dye lasers, high temperature superconducting (HTSC) (monocrystal Y-Ba-Cu-O with critical temperature Tc equals 87 K) and metal (Ni) thin films have been investigated. A self-diffraction process efficiency (eta) versus biharmonic pumping component detuning (Omega) has been measured at the temperature (Theta) equals 300 and 80 K. It is found that there is a well-defined dip on the dispersion curve (eta) ((Omega) ) for the HTSC films at (Theta) equals 80 K and -10 cm-1 (Omega) -50 cm-1. This region upper limit corresponds to a superconducting energy gap value 2(Delta) . At 10 cm-1 -1, any distinction of the same type is absent. In other respects all obtained dispersion curves are similar. They consist of the central peak ((eta) approximately equals 10-7, (Omega) -1) and wide wings ((eta) approximately equals 10-9, (Omega) 10 cm-1) with the interference structure. Y-Ba-Cu-O film resonances are coincided with the phonon mode frequencies (120, 335, and 580 cm equals -1). It is shown that photoexcitation kinetics (the sample ''darkening'') must consist of some components. A characteristic time of the most ''ultrafast'' component below 5 fs has been estimated and a complex subpicosecond quantum beats presence has been predicted.

Paper Details

Date Published: 30 November 1992
PDF: 6 pages
Proc. SPIE 1842, Mode-Locked Lasers and Ultrafast Phenomena, (30 November 1992); doi: 10.1117/12.131857
Show Author Affiliations
Victor N. Bagratashvili, Scientific Research Ctr. for Technological Lasers (Russia)
Vladimir A. Lobastov, Scientific Research Ctr. for Technological Lasers (Russia)
Alexander N. Zherikhin, Scientific Research Ctr. for Technological Lasers (Russia)
V. M. Petnikova, Moscow State Univ. (Russia)
Vladimir V. Shuvalov, Moscow State Univ. (Russia)


Published in SPIE Proceedings Vol. 1842:
Mode-Locked Lasers and Ultrafast Phenomena
Gregory B. Altshuler, Editor(s)

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