Surface-plasmon-polariton band structure of nanostructured multi-layer systems

We calculate the optical response of multi-layer systems where at least one layer contains arrays of metalic substructures of nanometer size. The dependence on lattice constant and excitation energy is studied systematically. An - at first glance non-intuitive - dependence of the plasmon intensity on the geometry of the metalic substructures is observed numerically. Generalizing the work of Park and Lee [PRL 95, 103902 (2005)], the results are interpreted in terms of plasmon-plasmon and plasmon-radiation couplings of different strength. A rich surface-plasmon-polarition bandstructure with ``gaps'' due to avoided crossings is seen. Super- and subradiant modes are found in the vicinity of those features.