Regensburg 2007 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 2: Internal Symposium “Nonlinearities of Photonic Materials”
DF 2.5: Vortrag
Montag, 26. März 2007, 11:40–12:00, H11
Optical excitation of space-charge waves in semi-insulating materials — •Mikhail Petrov1, Valeriy Bryksin1, Michaela Lemmer2, and Mirco Imlau2 — 1Ioffe Physico-Technical Institute, St. Peterburg, Russia — 2Department of Physics, University of Osnabrück, Germany
The application of an electric field to a semi-insulating (SI) crystal can create conditions for the existence of definite space-charge wave eigenmodes. Specific properties of these waves (dispersion law, quality factor) depend on intrinsic properties of the SI material (carrier mobility and lifetime, trap concentration, Maxwell relaxation time). Because these materials are typically good photoconductors, a proper illumination of the crystal can generate the desired space-charge waves with corresponding wave vector and eigenfrequency. This report is devoted to the discussion of a broad spectrum of the effects caused by optical excitation of space-charge waves. Some of these effects have direct analogs in nonlinear optics (for instance, complete rectification of space-charge waves reminds of optical rectification in nonlinear optics). The experiments have been performed in photorefractive crystals of the sillenite family (BSO, BTO, BGO) and SI semiconductors (CdTe:Ge, SiC, InP:Fe). New prospects of the investigations are discussed. They are the interaction of optically generated space-charge waves with magnetic field and investigation of space-charge waves in pseudo-two-dimensional structures when a crystal is illuminated with light that is absorbed in a thin surface layer of the crystal.
Supported by the DFG (projects GRK 695 and 436 RUS 17/15/07)