Regensburg 2022 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

HL: Fachverband Halbleiterphysik

HL 22: Heterostructures, Interfaces and Surfaces

HL 22.7: Talk

Wednesday, September 7, 2022, 17:00–17:15, H33

Time-resolved measurement of propagating exciton-polariton condensates in confined systems using a streak camera — •Christian Mayer, Simon Betzold, Philipp Gagel, Tristan H. Harder, Monika Emmerling, Adriana Wolf, Fauzia Jabeen, Sven Höfling, and Sebastian Klembt — Technische Physik, RCCM and Würzburg-Dresden Cluster of Excellence ct.qmat, University of Würzburg, Germany

Strong coupling between photons and excitons in an optical microcavity leads to the formation of hybrid light-matter quasiparticles called exciton-polaritons. In the low-density regime, these particles follow bosonic statistics and can therefore undergo dynamical condensation above a critical particle density by stimulated relaxation to the ground state. The low effective mass of polaritons compared to excitons, which results from the photonic fraction, leads to comparatively long diffusion lengths. The excitonic fraction, on the other hand, is responsible for relevant polariton-polariton interaction, which leads to a repulsive behavior. Exciting non-resonantly with a pulsed laser results in an additional repulsive force at finite wavevector due to the exciton reservoir. These factors can lead to a significant propagation of the polariton condensate, with relevant effects already taking place on the time scale of a few picoseconds.

Here, we utilize electron beam lithography and etching techniques to form potential landscapes such as coupled resonator lattices and waveguides. We use a streak camera to resolve and visualize the propagation of polaritons in these systems.