Splitting of a surface plasmon polariton beam by chains of nanoparticles

The operation of a micro-optical beam splitter for surface plasmon polaritons (SPP's) formed by lined up scatterers is modeled and studied in the framework of a vectorial dipolar approach for multiple SPP scattering by equivalent non-spherical nanoparticles. It is shown that the inclusion of anisotropic polarizability of individual scatterer in the vectorial dipolar model of multiple SPP scattering allows one to obtain, in some cases, quantitative agreement between modeling and experimental results. As an example, we apply this approach to model an SPP beam-splitter formed by a chain of spheroidal particles. The dependencies of the splitting efficiency on the shape of particles, the incidence angle and the waist of an incident SPP Gaussian beam are considered. It is found that the efficiency is very sensitive to the shape of scatterers and the angle of SPP beam incidence. Comparison of numerical results with experimental data shows good agreement with respect to the particle shape and incident angular dependences.