Regensburg 2013 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 10: Optical and nonlinear optical properties, photonic
DF 10.1: Vortrag
Dienstag, 12. März 2013, 09:30–09:50, H11
Transient gratings based on small polarons in nominally undoped, thermally reduced LiNbO3 — •Hauke Bruening1, Holger Badorreck1, Kay-Michael Voit1, Volker Dieckmann1, Gabor Corradi2, Christoph Merschjann3, and Mirco Imlau1 — 1Department of Physics, University of Osnabrück, Germany — 2Wigner Research Centre for Physics, Budapest, Hungary — 3Helmholtz-Zentrum für Materialien und Energie, Berlin, Germany
We studied a new type of hologram recording in nominally undoped, thermally reduced LiNbO3 by means of single intense ns-laser pulses (λ = 532 nm) yielding short-lived volume phase-gratings with high diffraction efficiencies η. The gratings are probed in the blue-green spectral range (λ = 488 nm) [1] and the NIR spectral range (λ = 785 nm) [2]. They show unique features like a stretched-exponential relaxation behavior with a lifetime in the ms-range at room temperature, an accelerated decay with increased temperature and a pronounced dependence of η on the orientation of the grating vector with respect to the polar c-axis. These properties can be explained comprehensively by taking an optically generated, spatial modulated density of small polarons into account. Therefor, this new recording mechanism is of particular interest for the field of nonlinear and ultrafast photonics because of the fast small polaron generation on the fs-scale.
*Financial support by the DFG (IM37/5 and INST190/137-1) and DAAD (50445542) is gratefully acknowledged.
[1] H. Bruening et al., Optics Express 20, 13326 (2012)
[2] M. Imlau et al., Optics Express 19, 15322 (2011)