Optomechanical amplification driven by interference of phonon-exciton and phonon-photon couplings

We study theoretically optomechanical damping and amplification spectra for vibrations interacting with excitonic polaritons in a zero-dimensional microcavity. We demonstrate that the spectra strongly depend on the ratio of the exciton-phonon and the photon-phonon coupling constants. The interference between these couplings enables a situation when optomechanical gain exists either only for a lower polaritonic resonance or only for an upper polaritonic resonance. Our results provide insight into the optomechanical interactions in various multimode systems, where several resonant oscillators, such as photons, plasmons, or excitons, are coupled to the same vibration mode.