Résumé:

Spatial observation and optical manipulation of polariton quantum liquids are raising a large interest in the studies of polariton condensates inmicrocavities [1]. In this work, we report the study of polariton propagation in a full hybrid ZnO microcavity where the condensation of polaritons up to room temperature has recently been achieved [2]. One particularity of this cavity is its thickness gradient, allowing the access to a large range of exciton-photon detunings. This thickness gradient is also interesting because it creates a dragging force for polaritons and polariton condensates. It is therefore important to measure the spatial distribution of the condensate with respect to the exciting laser spot in order to identify the condensation regimes. Using tomography, we have measured the 2D spatial image of the polariton emission below and above threshold attemperatures ranging from 10K to 300K. We are able to study the diffusion and propagation of a polaritons depending on the exciton density as well as on the microcavity thickness gradient. Figure 1 presents the photoluminescence spectra and the spectrally resolved images, and evidences an asymetric polariton propagation above threshold. This is a first step towards the optical manipulation of macroscopic quantum fluids in ZnO at room temperature. The authors acknowledge financial support from FP7 program through ITN networks CLERMONT4 (235114). References [1] E. Wertz et al., Phys. Rev. Lett. 109, 216404 (2012) [2] F. Li et al., Phys. Rev. Lett. 110, 196406 (2013)