Rigorous Characterization Of Surface Plasmon Modes By Using The Finite Element Method

Surface plasmons are confined to the surfaces which interact strongly with the electromagnetic waves. They occur at the interfaces where the relative permittivities of the bounding materials are of opposite sign. It is well know that some metals and highly doped semiconductor shows highly negative relative permittivity and such a structure with a dielectric cladding can support surface plasmon modes. These modes decay exponentially, they can be highly localised and can also be confined inside a sub-wavelength size guided wave structure. A rigorous full vectorial finite element-based approach has been developed to characterize a wide range of plasmonic devices, both at optical and terahertz frequencies. Results for wave confinement in quantum cascaded lasers for terahertz (THz) frequencies and metal coated photonic crystal fibres are presented.