Nonlinear emission from II–VI photonic dots in the strong coupling regime

We demonstrate nonlinear emission from CdMgMnTe-based pillar microcavities in the strong coupling regime under nonresonant excitation. The three-dimensional optical confinement is evidenced by the occurrence of discrete optical modes with a characteristic, size-dependent energy splitting. The threshold characteristics as well as the emission energy are studied as a function of photon–exciton detuning and sample temperature. Most strikingly, for small detunings an anomalous change of the mode separation with temperature is obtained in case of nonlinear emission which we attribute to a temperature-induced transition from the strong to the weak coupling regime.