Grazing incidence energy loss of an atomic beam in thermal evanescent field of polaritons near a smooth dielectric/semiconductor surface

We explore grazing incidence energy loss of a Cs+ beam reflected from amorphous dielectric/semiconductor surfaces supporting microwave modes. The theoretical analysis shows that a significant part of the beam will be neutralized and therefore, the energy loss of neutrals allows to get direct information about "van der Waals friction" force, which has not yet been obtained using other methods. We study conditions for the resonance interaction between Cs atoms and polariton modes on the surfaces of bulk materials and thin films, where the corresponding effects prove to be more effective. Our calculations show that at the optimized conditions (gamma(in) = 0.1-1 mrad, E-0 similar to 50-100 KeV) the "van der Waals friction" turns out to give a noticeable contribution to the total energy loss, with a characteristic dependence on temperature, velocity and material parameters. (c) 2005 Elsevier B.V. All rights reserved.