Theoretical Analysis of Hybrid Plasmonic Waveguide

We investigate the properties of the modes supported by the hybrid plasmonic waveguide consisting of a metal surface separated from a high-index slab by a low-index spacer. We examine the variations of the effective mode indices and field profiles of the hybrid modes for various choices of waveguide dimensions. We show that the observed variations of the modal properties can be explained from the fact that these modes result from the coupling of the surface plasmons, supported by the metal-dielectric interface, and the dielectric waveguide mode, supported by the high-index slab. The method of analysis is very general and can be used to explain the modal properties of the hybrid plasmonic waveguides for a wide range of material properties and waveguide dimensions.