PHASE AND AMPLITUDE BEHAVIOR IN CONICAL DIFFRACTION NEAR THE RESONANT EXCITATION OF SURFACE-PLASMONS

The efficiencies and phase shifts of light specularly reflected by corrugated metallic gratings in conical mounting are studied by means of rigorous formalisms based on conformal and non-conformal transformations. The reflected field is separated into components co- and cross-polarized with respect to p- and s-polarized incident waves. The efficiency of these components and their relative phase shifts are calculated as functions of the angles of incidence in regions where coupling between light and surface plasmons occurs. The sensitivity of the efficiency of p-s conversion to changes in grating geometry is tested by comparing results obtained for cycloidal, sinusoidal and triangular profiles with different groove heights.