Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 59: Optical Properties II
HL 59.2: Vortrag
Mittwoch, 9. März 2016, 15:00–15:15, H10
Probing the carrier reservoir across the polariton condensation and photon lasing transitions in a quantum well microcavity — •Sebastian Brodbeck1, Holger Suchomel1, Matthias Amthor1, Theresa Steinl1, Martin Kamp1, Christian Schneider1, and Sven Höfling1,2 — 1Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, 97074 Würzburg — 2SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, KY 16 9SS, United Kingdom
We monitor the free carrier reservoir in a GaAs-based quantum well microcavity under non-resonant pulsed optical pumping by measuring the photocurrent between lateral contacts deposited directly on the quantum wells that are partially exposed by wet chemical etching. We identify two clear thresholds in the input-output characteristic of the photoluminescence signal which can be attributed to polariton condensation and photon lasing, respectively. The power dependence of the probed photocurrent shows a distinct kink at the threshold power for photon lasing due to increased radiative recombination of free carriers as stimulated emission into the cavity mode sets in. At the polariton condensation threshold on the other hand, the nonlinear increase of the luminescence is caused by stimulated scattering of exciton-polaritons to the ground state which do not contribute directly to the photocurrent. In the strong coupling regime, the system can be described by a rate equation model which includes field ionization related losses.