ATOMIC DIFFRACTION ASSISTED BY A STIMULATED RAMAN TRANSITION

We show that internal state transitions may induce energy transfer amo ng different directions of motion and lead efficiently to large scatte ring angles in atomic reflection from evanescent-wave mirrors; The pro posed scattering mechanism is reminiscent of the so-called Sisyphus ef fect of laser cooling. Perturbative calculations are presented acid di scussed for the diffraction of atomic beams at grazing incidence on ev anescent fields with polarization gradients and for the reflection of atoms by a rough mirror.