Nonguiding semiconductor microcavity: Exciton-photon mode splitting and photoluminescence dynamics

We report on the fabrication of a nonguiding half-wave semiconductor microcavity containing two quantum wells, and present time resolved photoluminescence measurements under resonant and non-resonant excitation with a variable detuning between the cavity and the quantum well exciton. When tuning the cavity length, the emission spectra present the characteristic polariton-like dispersion branches with a 4.6 meV splitting at the anti-crossing. On the exciton-like part of each branch, the emission dynamics is similar to the emission of a bare quantum well. However on the photon-like part, the radiative lifetime is considerably shortened. We describe these features by a polariton type model: mixed exciton-photon states arise from the strong radiative coupling between the two oscillators and present a radiative decay time which reflects the respective proportion of exciton and photon in their wavefunction.