Optical cavity enhancement of light–sound interaction in acoustic phonon cavities

We describe a device that has a resonant cavity for acoustic phonons embedded inside an optical cavity. This double cavity structure is a resonator for acoustical phonons and enhances the interaction between sound and light. We discuss the design and material parameters relevant for the optimization of the acoustic phonon cavities, and we present Raman scattering experiments on GaAs/AlAs structures designed to confine from one to three acoustical phonon modes. We quantitatively study the amplification of the photon–phonon interaction in these devices reporting an enhancement factor of more than five orders of magnitude.