Dipolar emitters at nanoscale proximity of metal surfaces: Giant enhancement of relaxation in microscopic theory

We consider a nanoscale dipolar emitter (quantum dot, atom, fluorescent molecule, or rare-earth ion) in a nanometer proximity to a flat metal surface. There is strong interaction of this emitter with unscreened metal electrons in the surface nanolayer that causes enhanced relaxation due to surface plasmon excitation and Landau damping. To describe these phenomena, we developed analytical theory based on local random-phase approximation. For the system considered, conventional theory based on metal as continuous dielectric fails both qualitatively and quantitatively. Applications of the present theory and related phenomena are discussed.