Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 50: III-V Semiconductors II (mainly Arsenides)
HL 50.4: Vortrag
Mittwoch, 28. März 2012, 10:15–10:30, EW 203
Zeeman splitting and diamagnetic shift of spatially confined quantum-well exciton polaritons in an external magnetic field — •Arash Rahimi-Iman1, Christian Schneider1, Julian Fischer1, Steffen Holzinger1, Matthias Amthor1, Lukas Worschech1, Alfred Forchel1, Stephan Reitzenstein1,2, Sven Höfling1, and Martin Kamp1 — 1Technische Physik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — 2Present address: Institute of Solid State Physics, Technische Universität Berlin, D-10623 Berlin, Germany
We report on pronounced magneto-optical effects of spatially confined polariton modes in an InGaAs quantum well microcavity. The polaritons were trapped by a lithographically modulated cavity length. In contrast to etched structures suffering from nonradiative recombination, this approach allows for a gentle modification of the dielectric properties and results in a confinement potential of 7.5 meV. In the presence of an external magnetic field, a diamagnetic shift and Zeeman splitting of the quantized modes were observed for different trap diameters, ranging from 1 to 10 µm. This confirms that the polaritonic properties of the emission modes are preserved even for small traps. Moreover, a clear correlation between the magnetic response and the excitonic fraction of the polaritons was identified by magnetic field-dependent measurements which could be confirmed by a simple Hopfield coefficient model. For 10-µm trap modes, such magneto-optical effects were obtained over a broad range of k-vectors and angular mode numbers, providing evidence of strong coupling for all detected modes.