Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 55: Photonic crystals

HL 55.3: Talk

Friday, March 31, 2006, 12:00–12:15, BEY 154

Cavity-polariton interaction mediated by coherent acoustic phonons — •Mauricio de Lima¹, Rudolf Hey¹, Paulo Santos¹, Mike van der Poel², and Jørn Hvam² — ¹Paul-Drude-Institut für Festkörperelektronik — ²Research center COM, Technical University of Denamark

The strong coupling between excitons in a quantum well (QW) and photons inserted in a semiconductor microcavity leads to the formation of quasi-particles known as cavity-polaritons. In this contribution, we investigate the interaction of the polaritons with coherent acoustic phonons in the form of surface acoustic waves (SAWs). The studies were performed in a GaAs QW embedded in a (Al,Ga)As/AlAs microcavity. The periodic modulation introduced by the phonons folds the cavity-polariton dispersion within a mini-Brillouin zone (MBZ) defined by the phonon wave vector (k_SAW). The appearance of well-defined mini-gaps at the edge of the MBZ as well as folded modes in the center of the MBZ are observed for different phonon densities and different cavity polariton detuning energies. The experimental results are in good agreement with calculations that take into account the modulation of the the band-gap and of the optical thickness of the microcavity spacer layer by the SAW strain field.