Resonance scattering and absorption of light by finite two-period gratings of circular silver nanowires

Abstract

We consider the two-dimensional scattering of the H-polarized electromagnetic plane waves of the visible range by three types of gratings made of periodically arranged circular cylindrical sub-wavelength wires. Using the field expansions in local coordinates and addition theorems for cylindrical functions, we obtain a block-type matrix equation for the field expansion coefficients. This equation is of the Fredholm second-kind form that guarantees convergence of numerical solution. The scattering and absorption cross-sections and the near-field patterns are computed. The interplay of plasmon and grating-type resonances is studied for two and three-layer gratings of identical periods, stacked two-period gratings, and in-line two-period gratings made of nano-diameter silver wires.