Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 90: Poster Session: Quantum information systems; Optical properties; Ultrafast phenomena

HL 90.13: Poster

Donnerstag, 14. März 2013, 16:00–20:00, Poster A

Studying Ultrafast Quasiparticle Dynamics by Inelastic Scattering of Electromagnetic Waves: Part 1 Visible Light — •André Bojahr, Marc Herzog, Jevgenij Goldshteyn, Steffen Mitzscherling, Lena Maerten, and Matias Bargheer — Intstitut für Physik und Astronomie, Universität Potsdam, Germany

Collective excitations in crystalline materials lead to complex physical phenomena such as metal-insulator or magnetic phase transitions. Phonons often have a participating or driving role in such transitions. Therefore studying phonons and their coupling among each other and to other subsystems of the material is very important for the understanding of the underlying physics. Here we show new experiments which support a generalized view on scattering of electromagnetic waves from quasiparticles. In particular we study phonons and phonon-polaritons in different perovskite oxides such as SrTiO3 or LiNbO3. We use three different excitation schemes to generate ultrashort quasi-monochromatic phonons and phonon-polaritons. After excitation we probe the quasiparticle dynamics in real time by Brillouin- and Raman scattering. We discuss the experiments in a unified view, where the pump- and probe-process are disentangled and the inelastic aspect of the scattering is emphasized. We observe the quasiparticle dynamics including the phonon damping and nonlinear interaction in real time, and compare the results to simulations in a nonlinear masses-and-springs model.