Interaction between a high-density polariton phase and the exciton environment in semiconductor microcavities

Abstract

Spontaneous polariton coherence is observed following creation of a cool exciton distribution in a GaAs-based semiconductor microcavity. Interactions between the high density polariton state and high-$k$ excitons result in a blueshift in energy and are shown to limit the temporal coherence of the polariton phase to $10--20\phantom{\rule{0.3em}{0ex}}\mathrm{ps}$. The effect of exciton-polariton interaction is also revealed in two beam experiments where the coherence of the polariton optical parametric oscillator is strongly suppressed by the creation of a reservoir population. These interactions are likely to be important in any polariton high density phase created under conditions of nonresonant excitation.