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HL: Fachverband Halbleiterphysik
HL 108: Poster: Ultra-fast phenomena / Optical properties / Semiconductor laser / Devices and device concepts
HL 108.8: Poster
Donnerstag, 3. April 2014, 17:00–20:00, P1
Parametric scattering in a multimode polariton system — •Rüdiger Schmidt-Grund1, Christof P. Dietrich1, Tom Michalsky1, Robert Johne2, Paul Eastham3, Helena Franke1, Chris Sturm1, Martin Lange1, and Marius Grundmann1 — 1Universität Leipzig, Institut für Experimentelle Physik II, Leipzig, Germany — 2Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 3Trinity College Dublin, Dublin, Ireland
We present the observation of parametric scattering of whispering gallery mode exciton-polaritons in a ZnO micro-wire resonator at low temperature. In this geometry, in contrast to a planar microcavity, many polariton modes exist, and furthermore the ground state is energetically well separated from the exciton energy. In this complex many-mode system, we observe the formation of a polariton Bose-Einstein condensate with some special features. First, it is resonantly fed by the radiative decay of defect bound excitons and secondly it appears in polariton branches energetically close to this defect bound exciton state. By increasing the excitation power, the occupation of this initial state becomes very high and a parametric scattering process sets in. Thereby, a relaxation of the condensed polaritons into states with lower energy and higher momentum occurs. The experimental findings are in good agreement with theoretical simulations taking into account polariton-polariton scattering in a multi-mode system.