Diffraction-limited laser excitation of a surface plasma wave and its scattering on a rippled metallic surface

A theory of excitation, reflection, and scattering of a surface plasma wave (SPW) over a metallic surface is presented by modeling a localized surface ripple by an electron density perturbation. The level of a laser excited SPW is significantly lowered by the diffraction effects. When an SPW is incident on a bump or a slot, it undergoes specular reflection. It also undergoes elastic scattering when encountering a surface defect, as observed in recent experiments.