Detailed study of a high-finesse planar waveguide for evanescent wave atomic mirrors

We have realized a resonant waveguide structure which enhances the intensity of an evanescent wave at a dielectric-vacuum interface by more than three orders of magnitude. We present a simple theoretical model including the effect of the losses in the waveguide, which gives a good description of the observed behaviour of the structure. We experimentally determine the enhancement factor by analysing the resonance of the reflected light intensity. This characterization technique allows for an easy in situ monitoring of the enhancement, which is a key feature for the understanding of atomic mirror experiments.