Near-field effect in quantum optics of surface: spontaneous emission in ultra-thin dielectric film

We have theoretically investigated the process of spontaneous emission of initially excited two-level atom inside and outside of ultra-thin dielectric film. Dielectric medium is considered as discrete-continuous system of interacting dipoles. For the solution of this boundary problem of quantum optics we use Heisenberg equations for atomic operators. Mode functions of ultra-thin film are calculated by direct solution of integro-differential field equation. Coordinate dependences of excited state life time are analysed and it is shown that consideration of near-field effect may essentially change spectral properties of the atoms located at small distances from the surface.