Coplanar gratings of multiple thin noble-metal nano-strips as surface plasmon resonance structures

Coplanar configurations of multiple thin flat nanosize silver strips in the air are considered as optical antennas. We investigate the light scattering and absorption by the mentioned nanostructures and study the nature of the associated surface-plasmon resonances. This is done using new accurate and efficient numerical model based on two-side generalized boundary conditions (GBCs) on each strip, two independent sets of the coupled singular integral equations on the median lines of the strips, and the Nystrom-type discretization with the aid of specially tailored quadrature formulas. Such numerical technique, also known as the method of discrete singularities, is numerically efficient and guarantees fast convergence and controlled accuracy of computations. We present the results of computations, which include the wavelength scans of the total scattering cross-sections and the absorption cross-sections of the finite-periodic gratings made of silver and the near and far field patterns.