DETECTING BOUNCING ATOMS

We report on recent experiments to observe the reflection of atoms off an enhanced evanescent wave. Optical measurements yield an enhancemen t factor of three orders of magnitude for the intensity of the evanesc ent wave. We have thus reflected atoms with detunings up to 140 GHz. W e present results showing that the atoms at normal incidence are not r eflected specularly but with an additional spreading of four recoil ve locities in the direction orthogonal to the incidence direction. This effect is attributed to the surface roughness of the prism.