Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 30: Heterostructures, interfaces, and surfaces

HL 30.7: Vortrag

Mittwoch, 14. März 2018, 16:45–17:00, EW 202

Tracing dark exciton dynamics with optical bistable exciton polaritons in planar microcavities — •Daniel Schmidt¹, Bernd Berger¹, Manfred Bayer¹, Christian Schneider², Sven Höfling², and Marc Aßmann¹ — ¹Technische Universität Dortmund, 44227 Dortmund, Deutschland — ²Technische Physik, Universität Würzburg, 97074 Würzburg, Deutschland

In the quickly thriving field of quantum computation exists a demand in systems that can be derived by using quantum mechanical methods. To fulfill such demands, various research has been done on exciton polaritons in semiconductor microcavities that arise due to the strong coupling of cavity photons and quantum well excitons. Furthermore, their ability to be reconfigured by controlling them all-optically makes them even more promising candidates. Another striking feature of exciton polaritons is the nonlinear polariton-polariton interaction. At high pumping densities these interactions may induce various phenomena, such as Bose-Einstein condensation, superfluidity or optical bistability. The latter is created by using slightly off-resonant CW excitation that generates a blueshift of the lower polariton branch, resulting in a hysteresis of the input-output behavior of the exciton polaritons. Utilizing this behavior, we use an additional short far off-resonant laser pulse to perturb the bistable system, enabling access to the dynamics of the lower polariton branch. Here, these dynamics show surprisingly long recovery times, which hints the presence of a reservoir of dark excitons involved in this process.