Plasmonic mediated interactions between waveguides and nanostructured metal surfaces

We present the polarization resolved, angular dependent, optical reflectance properties for single TE mode optical waveguides in contact with a nanostructured gold surface. A substantial angle dependent resonant decrease in the TE polarized surface reflectivity is measured which cannot be explained by a simple waveguide coupling due to surface roughness. Rather we show that the resonance is due to the excitation of a coupled waveguide-plasmonic surface mode created by the interaction between the metal nanostructure and the waveguide. A model based on coupled mode theory is introduced in order to explain the experimental data.