Surface plasmons with phase singularities and their effects on matter

We explain how a surface plasmon optical vortex can be created when a laser beam with a phase singularity such as Laguerre-Gaussian light is totally internally reflected at the planar surface of a dielectric on which a metallic thin film is deposited. The light field in the vacuum region is evanescent in that it decays with distance perpendicular to the film surface, but significantly, it retains the phase singularity of the original light beam and also the orbital angular momentum carried by that beam. We describe the essential features of such surface optical vortices and discuss how they can, in principle, be used to influence atoms localised in the vicinity of the surface. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim