Regensburg 2007 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 11: Poster Session
DF 11.17: Poster
Donnerstag, 29. März 2007, 14:30–18:00, Poster C
Amplification behavior of photo-induced near-surface scattering — •Volker Dieckmann, Andreas Selinger, and Mirco Imlau — Department of Physics, University of Osnabrück, Barbarastr. 7, D-49069 Osnabrück, Germany
The influence of the crystal thickness on photo-induced surface, near-surface and bulk scattering phenomena is investigated in iron-doped lithium niobate (0.1 wt. % Fe). Crystals of thickness d between 0.1 mm and 4 mm are illuminated perpendicular to their c-axis by extraordinary polarized light of wavelength 532 nm and intensities up to 10 kW/m2. Four scattering patterns develop: i) polarization-isotropic lobes in ±c-direction of the sample (Ashkin et al., Phys. Lett. 9, 72, 1966), ii) a polarization-anisotropic ring (Temple et. al., J. Opt. Soc. Am. B 3, 337 (1986)), iii) a polarization-isotropic line perpendicular to the c-axis (Morozovska et. al., Sem. Phys. Quant. Elec. Optoelec. 6, 324 (2003)) and iv) a polarization-anisotropic elliptical-shaped pattern (A. Selinger et. al., TOPS 99, 61 (2005)). The first two pattern result from parametric processes and their thickness dependence of the steady-state scattered intensity Is follows the well known amplification law Is∝exp(Γ d), with the gain factor Γ. Pattern iii) is known to result from a photo-induced formation of ferroelectric domains. Hence its amplification is thickness independent. The elliptical-shaped pattern shows an unusual amplification behavior. Its steady-state intensity of the scattered light decreases with increasing sample thickness.
Financial support by the DFG (projects IM 37/2-2, GRK 695).