Résumé
This thesis is dedicated to the strong coupling regime between excitons and photons at room temperature in bulk ZnO-based microcavities grown on Si (111) substrate by molecular beam epitaxy. A preliminary theoretical study shows that the continuum absorption of excitonic resonances is responsible for the observed strong damping on the upper polariton branch, without affecting the lower polariton branch. The strong coupling regime, at room temperature, of the cavity mode and the Bragg modes of the microcavity is then demonstrated by angle-resolved spectroscopy. Moreover, we observe the presence of a bottleneck on the Bragg mode polariton branch. The latter may be suppressed by increasing the exciton density or the temperature. We compare our experimental results with recent theoretical predictions and discuss the achievement of the polariton laser regime.