Using carefully designed hybrid metal-dielectric resonators, we study molecular optomechanics in the strong coupling regime ($g_{ \rm }^2/\omega_m { >} \kappa$), which manifests in anharmonic emission lines in the sideband-resolved region of the cavity-emitted spectrum ($\kappa{ <}\omega_m$). This nonlinear optomechanical strong coupling regime is enabled through a metal-dielectric cavity system that yields not only deep sub-wavelength 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.
Categories: cond-mat.mes-hall physics.optics quant-ph