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. (C) 2003 Elsevier B.V. All rights reserved.