ABSTRACT

In the present work we investigate by means of nonlinear optical methods the influence of metallic surfaces of given roughness and of dielectric surfaces on lifetime damping and transition energy shifts of isolated atoms. The surface roughness is characterized by atomic force microscopy, and ultrathin (<3 nm) organic films are deposited on top of the metal substrates, thus serving as spacer layers between atoms and surfaces. Structure and orientation of the spacer layers are determined microscopically via low energy electron deflection techniques. Those investigations are of importance for the treatment of problems in such diverse fields as growth of nanoscaled metal-organic films or metal/insulator layered systems (e.g., nanocapacitors), cavity quantum electrodynamics, fluorescence enhancement in microdroplets and imaging and spectroscopy of isolated molecules via scanning near field microscopy.

By comparison with different theoretical approaches we demonstrate that the experimental results can be reproduced satisfactorily only by taking into account the quantummechanical and multilevel nature of the system as well as multipole surface plasmon excitations in the roughness (“selvedge”) region of the surface. Similarly, nonlocality in the light-matter interaction near interfaces also dominates the power spectrum of atoms near dielectric surfaces.