Theory of evanescent mode atomic mirrors with a metallic layer - art. no. 033405

Dielectric atomic mirrors are considered in which the repulsive force field owes its existence to an evanescent mode in the presence of a metallic cap ping layer. The theory of such an atomic minor is constructed, assuming a f inite thickness of the metallic layer with a finite plasma frequency and ad opting the field-dipole orientation picture. The Rabi frequency together wi th the reflectivity for the light incident from within the substrate are ev aluated, and their variations with the type of metal and layer thickness an alyzed as useful indicators of the effectiveness of the system as an atomic mirror. A number of interesting features are pointed out, including a desi rable enhancement. Solutions of the equation of motion for a given atom, su bject to given initial conditions, lead to trajectories exhibiting reflecti on. The leading force fields controlling the dynamics include the average d ipole image force plus the average light-induced forces due to the evanesce nt field. The parameters used to compute the trajectories are similar to th ose in recent experiments in which Rb atoms incident on a silver film depos ited on a glass substrate have been shown to experience enhanced mirror act ion. The factors controlling the enhancement in general are pointed out and discussed.