Strong and weak coupling regime in pillar semiconductor microcavities

We present photoluminescence measurements in pillar microcavities containing GaAs quantum wells. The strong coupling regime between excitons and zero-dimensional photon modes is evidenced by a characteristic anticrossing behavior, with a constant Rabi splitting down to 1 μm radius. Moreover, since semiconductor Bragg mirrors have a finite angular acceptance, a large fraction of the radiant excitons are weakly coupled to the leaky modes. We show that this emission is confined in the pillar and diffracted through the top surface. Its relative intensity increases when reducing the pillar radius. We also report the largest Rabi splitting ever obtained in III-V compounds using a microcavity filled-up with quantum wells.