The formation and propagation of a polariton condensate under tightly focused excitation is investigated in a ZnO microcavity both experimentally and theoretically. Two-dimensional (2D) near-field and far-field images of the condensate are measured under quasicontinuous nonresonant excitation. The corresponding spatial profiles are compared to a model based on the Gross-Pitaevskii equation under cylindrical geometry. This paper allows one to connect the experiments performed with a small excitation laser spot and the previous kinetic models of condensation in a 2D infinite microcavity and to determine the relevant parameters of both the interaction and the relaxation between the reservoir and the condensate. Two main parameters are identified: The exciton-photon detuning through the polariton effective mass and the temperature, which determines the efficiency of the relaxation from the reservoir to the condensate.

• Received 22 October 2015
• Revised 30 November 2015
• Corrected 20 January 2016

DOI:https://doi.org/10.1103/PhysRevB.92.235308