Polariton trap in microcavities with metallic mirrors.

In planar microcavities with metallic mirrors the spectra of cavity polaritons may be strongly modified by the presence of a surface plasmon interacting with transverse-magnetic (TM)-polarized cavity modes. In particular, for certain parameters of the cavity, a minimum in the dispersion of the TM-polarized polariton may develop, which is located in the non-radiative part of the spectrum. This minimum may serve as a very effective trap for polariton population at high non-resonant excitation of the cavity.

In-gap polaritons in uniformly filled microcavities.

We examine the nature and the dispersion of new polariton modes, which appear in the polariton gap (i.e. within the Rabi splitting), considering the spectrum of polaritons in a planar microcavity uniformly filled with a resonant material and exhibiting the strong exciton-photon coupling regime. These additional modes are the consequence of the quantization of the excitonic states caused by the confinement. We consider these in-gap modes in materials typically used in microcavities and link the obtained results to experiments, where such in-gap states have indeed been observed. We show that the splitting between the in-gap modes and their bandwidth depend on the bandwidth of the exciton out of the microcavity and on the oscillator strength of the excitonic transition.