A novel algorithm for analysis of surface plasmon polaritons in metallic thin films

Electromagnetic scattering from periodic objects is of particular interest because they support waves bound to the surface of the structure. Specifically, dielectrics with negative real permittivity support charge density oscillations known as surface plasmons. The coupling between a surface wave and charge density oscillation is the so-called surface plasmon polariton (SPP). Research into nano-plasmon optics is growing into a rich research field, with far reaching implications. Metal films perforated by periodically distributed holes exhibit stronger transmission than that predicted by geometrical optics. Numerical modelling of perforated metal structures presents several computational challenges. Researchers have resorted to both volume and surface integral equations to model these effects. However, since the holes occupy only 5% of the area of the film, and the material itself has a large negative real permittivity, the discretization has to be sufficiently dense to capture the wave physics. We present an alternative method that is considerably more efficient, and requires only the region inside the hole to be meshed. The integral equation formulation of the scattering problem is presented. The periodic Green´s function for a layered medium is described. A method of moments scheme is detailed and some preliminary results are presented.