LO-phonon-enhanced microcavity polariton emission

We observe resonant enhancement of the microcavity exciton-polariton emission by more than three orders of magnitude when the excitation laser is tuned to a single longitudinal-optical-phonon energy above the polariton energies. Our finding provides a scheme to efficiently populate ${\mathrm{k}}_{\mathrm{\Vert }}$=0 polaritons which bypasses the slow-acoustic-phonon thermalization process.