Huge splitting of polariton states in microcavities under stress

The application of inhomogeneous stress, used to trap polaritons in a microcavity, results in a splitting between different polarization states of the polaritons. The splitting of the polariton states arises primarily from the splitting of the exciton states in the quantum wells embedded inside the microcavity due to the electron-hole exchange interaction and the mixing of the light- and heavy-hole excitons with stress. The new mixed exciton states have different oscillator strengths, thereby enhancing the splitting of the lower polaritons by a factor of four more than previously reported exciton spin splittings. We observe splittings between the different polarizations, at normal incidence, of almost 1 meV. The physical explanation and a corresponding simulation for the fine structure splitting of the polaritons observed in stressed microcavities are presented.