Cavity Control of Nonlinear Phononics*

Nonlinear interactions between phonon modes govern the behavior of vibrationally excited solids and molecules. We demonstrate here theoretically that optical cavities can be used to control the redistribution of energy from a highly-excited coherent infrared-active phonon state into the other vibrational degrees of freedom of the system. The hybridization of the infrared-active phonon mode and the fundamental mode of the cavity induces a polaritonic splitting that we use to tune the nonlinear interactions with other vibrational modes in and out of resonance. We show that not only can the efficiency of the redistribution of energy be enhanced or decreased, but also the underlying scattering mechanisms may be changed.