Surface plasmon polaritons on arrays of nanostructures with three-fold symmetry

The influence of nano-holes with three-fold symmetry on the excitation of surface plasmon polaritons (SPPs) at metallic nano-hole arrays is studied numerically for a quadratic array of rotor-shaped nano-holes cut into a silver film. It is found that the SPP-related minimum of the far-field reflectivity shifts as a function of the polarization angle of the incident light compared to rotational invariant hole-shapes. This was also reported in recent experiments. On contrast, the polarization angle for most efficient SPP-excitation is found to be independent of the nano-hole shape. We discuss optical near- and far-field properties of the considered structures.