DIFFUSE ATOMIC REFLECTION AT A ROUGH MIRROR

We present a theoretical analysis of the influence of surface roughnes s on the atomic reflection from an evanescent wave mirror. In our calc ulations we assume that light scattered at the rough dielectric surfac e interferes with the evanescent wave, creating a rough potential that scatters the atoms. We calculate the probability of diffuse reflectio n and the momentum distribution of the scattered atoms with a statisti cal model for the rough surface. The atomic reflection is diffuse rath er than specular if the surface roughness is comparable to the wavelen gth of the incident atoms. We discuss the spatial coherence of the ref lected matter waves. We indicate how to generalize our treatment to th e case of multilevel atoms.