Berlin 2015 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 9: Focused Session on Ferroic Domain Walls III (DF with MA)
DF 9.5: Vortrag
Dienstag, 17. März 2015, 15:20–15:40, EB 107
Investigation of second order nonlinear susceptibility tensor elements at the transition of ferroelectric domains — •Alex Widhalm1, Kai Spychala1, Moritz Grothe1, Gerhard Berth1,2, and Artur Zrenner1,2 — 1Department Physik, Universität Paderborn, 33098 Paderborn, Germany — 2Center for Optoelectronics and Photonics Paderborn (CeOPP), 33098 Paderborn, Germany
Second harmonic (SH) microscopy is an established method for characterizing periodically poled ferroelectric materials. This work focusses on mapping the second order susceptibility tensor elements in ferroelectric domain structures using spatially resolved second harmonic analysis with respect to a focused laser beam. Our novel nondestructive technique allows for a nonlinear confocal scanning probe microscopy as well as for a basic analysis of occurring point spread functions with respect to a fixed excitation point. The resulting complex distribution of polarization states of excitation and generated SH light, allows a prediction about the detectable nonlinear response of the whole system. Here the experimental results obtained by this method are in good agreement with the expected theoretical occurrence of the nonlinear field distributions. In our spatially resolved experiments we found, that in the transition region of contrarily poled domains and its immediate environment some susceptibility tensor elements disappear whereas other elements appear. This results strongly contribute to a deeper understanding of the occurring physics at domain walls and corresponding contrast mechanisms in ferroelectric domains respectively.