Liquid-Phase Vibrational Strong Coupling.

Light-matter strong coupling involving ground-state molecular vibrations is investigated for the first time in the liquid phase for a set of molecules placed in microcavities. By tuning the cavities, one or more vibrational modes can be coupled in parallel or in series, inducing a change in the vibrational frequencies of the bonds. These findings are of fundamental importance to fully develop light-matter strong coupling for applications in molecular and material sciences.