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HL: Fachverband Halbleiterphysik
HL 61: Focus Session: Tailored Nonlinear Photonics I
HL 61.7: Vortrag
Donnerstag, 19. März 2020, 12:15–12:30, POT 51
PSF-analysis of ferroelectric domain-walls in waveguide structures — •Peter Mackwitz, Laura Padberg, Christof Eigner, Christine Silberhorn, Gerhard Berth, and Artur Zrenner — Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
The occurring nonlinear contrast mechanism of periodically poled waveguide structures in LiNbO3 and KTiOPO4 is examined via a combined experimental and numerical approach. The numerical calculation is based on a vectorial model, whereby the experimental access is realized by a direct imaging technique which records the spatial distribution of the second-harmonic signal in the back focal plane. As the model depends on the optical properties of the material, different scenarios of contrast mechanisms can be simulated and compared to the experimental data. It turns out that many features of the nonlinear signatures arise from destructive interference of phase-shifted wavelets at the domain walls as well as the waveguide boundaries. The phase is acquired due to the interaction of the focus with differentially poled domains, whose susceptibility tensor appears rotated by 180∘. Another ingredient for the contrast are new tensor elements which do only occur at the domain walls. With this work a comprehensive explanation for the contrast mechanism in the coherent surface near regime is given.