Molecular Optomechanics in the Anharmonic Cavity-QED Regime Using Hybrid Metal–Dielectric Cavity Modes

Using carefully designed hybrid metal–dielectric resonators, we study molecular optomechanics in the strong coupling regime (g 2/ωm > κ), which manifests in anharmonic emission lines in the sideband-resolved region of the cavity-emitted spectrum (κ < ωm). This nonlinear optomechanical strong coupling regime is enabled through a metal–dielectric cavity system that yields not only deep-subwavelength plasmonic confinement but also dielectric-like confinement times that are more than two orders of magnitude larger than those from typical localized plasmon modes. These hybrid metal–dielectric cavity modes enable one to study new avenues of quantum plasmonics for single-molecule Raman scattering.