Butte, R.Levrat, J.Christmann, G.Feltin, E.Carlin, J. F.Grandjean, N.2010-10-052010-10-052010-10-05200910.1103/PhysRevB.80.233301https://infoscience.epfl.ch/handle/20.500.14299/55037WOS:000273228800008The signature of the strong-coupling regime is unambiguously evidenced in a GaN-based microcavity (MC) above the polariton lasing threshold P-thr at room temperature through the observation of the upper polariton branch. The MC system exhibits a renormalization of the polariton dispersion curve, namely, a reduced normal-mode splitting compared to the low-density regime. Next the dependence of P-thr as a function of exciton-photon detuning is investigated in the 4-340 K temperature range, which allows accessing the polariton lasing phase diagram. The observation of polariton lasing over such a broad range of temperatures reveals a clear transition from a kinetic to a thermodynamic regime with increasing temperature.gallium compoundsIII-V semiconductorsmicrocavitiesphase diagramspolaritonsrenormalisationBOSE-EINSTEIN CONDENSATIONQUANTUM MICROCAVITYtext::journal::journal article::research article