Cavity control of nonlinear phononics

Nonlinear interactions between phonon modes govern the behavior of vibrationally highly excited solids and molecules. Here we demonstrate theoretically control over the redistribution of energy from a highly excited coherent infrared-active phonon state into other vibrational degrees of freedom of the system using optical cavities. Specifically, we tune the polaritonic splitting of an infrared-active mode in the cavity so that it is pushed into resonance with other phonon modes of the system. This technique makes it possible to tune the efficiency of energy redistribution and even to change the underlying scattering mechanism, which possibly enables the creation of phonon-induced states in a broad scale of materials that do not naturally exhibit the required resonance conditions.