Dynamics of the transformation of bistable centers and lattice in CdF2 crystals under femtosecond pulsed photoexcitation

作者：Stasel'ko D I^*; Tikhomirov S A; Buganov O V; Shcheulin A S; Angervaks A E; Ryskin A I

来源：Optics and Spectroscopy, 2011, 110(1): 33-41.

DOI：10.1134/S0030400X1101022X

The kinetics of photoinduced absorption spectra of CdF2 crystals with bistable indium and gallium centers under femtosecond pulsed excitation has been experimentally investigated. Based on the example of indium ions, it is shown that the transmission band in the absorption spectrum of deep centers is formed for 0.8-1 ps, which significantly exceeds the photon absorption time. This process is interpreted as a result of displacement of indium ion from the initial interstitial position to a site of neighboring unit cell; the displacement velocity is estimated to be 200-250 m/s, a value close to the thermal velocity of this ion at room temperature. The times characteristic of the formation of free polarons as a result of the displacement of neighboring lattice ions have been experimentally estimated for the first time at a level of 0.8-1.2 ps. The capture times of free polarons by trivalent gallium and indium ions are estimated (5 and 10 ps, respectively), as well as the corresponding cross sections (2 x 10(-16) and 8 x 10(-16) cm(2)).

• 出版日期2011-1