Analytical theory of optical transmission through periodically structured metal films via tunnel-coupled surface polariton modes

Analytical calculations of light transmission through and reflection from periodically structured metal films due to tunnel coupling of surface plasmon polariton modes are presented. The influence of the adjacent media has been studied in both symmetric and asymmetric configurations. The transmission spectra have been analyzed in different regimes corresponding to double-resonant and single-resonant tunneling. The electromagnetic field configuration related to the surface polariton Bloch modes of the film has been derived that allows direct estimation of far- and near-field distributions of the reflected and transmitted light. The analytically calculated spectra are in a good agreement with numerical modeling as well as available experimental data. The theory provides a description of optical properties of periodically structured metal films with topography variations and∕or dielectric constant modulation.