Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 36: Poster Ib

HL 36.30: Poster

Dienstag, 8. März 2016, 15:00–19:00, Poster A

Temporal coherence properties of a polariton condensate in a disordered environment — Martin Thunert, •Stefan Lange, Helena Franke, Chris Sturm, Tom Michalsky, Marius Grundmann, and Rüdiger Schmidt-Grund — Universität Leipzig, Inst. für Exp. Physik II, Linnestr. 5, 04103 Leipzig

We report on the temporal coherence properties of an exciton-polariton Bose-Einstein condensate (BEC) in a disordered ZnO-based bulk planar microcavity (MC). The momentum space intensity distribution of the BEC emission is strongly influenced by disorder even at high excitation powers. We found theoretically that this lack of BEC stabilization relies on the driven dissipative nature of the condensate, leading to disorder induced, density independent phase fluctuations [1]. To prove whether the observed emission arises from a temporally coherent condensate, we applied interferometry measurements with variable path length difference or rather temporal delay between both interferometer arms. With this procedure, we found a coherence time of about 24 ps for the BEC emission, which is by a factor of 150 larger than the lifetime of the uncondensed polaritons [1]. Using time-resolved, energy-momentum-space imaging, BEC emission was observed up to 100 ps after the decay of the exciting laser pulse. Consequently, the coherence of the investigated quantum system is conserved during the multiple reabsorption and reemission processes that can thus be identified as a polariton condensate.

[1] M. Thunert, A. Janot et al., ArXiv (2014), arXiv:1412.8667