Dispersion of plasmon polaritons guided by a metal film of finite width deposited on a uniaxial substrate

Abstract

We discuss the propagation characteristics of surface plasmon modes supported by a thin lossy metal film of finite width deposited on a uniaxially anisotropic substrate, numerically evaluated using the method of lines. The metal film with finite width (strip waveguide) has been a subject of intensive study, both theoretically and experimentally, since it is the platform of choice for constructing plasmon circuits for optoelectronic integration, over the past few years. Plasmon waveguides with anisotropic dielectric environment have gained importance in research recently. Specifically, artificial substrate materials with strong anisotropy have been proposed as a means of improving the propagation range of plasmon polaritons in wide metal films. In our investigation, it is observed that the anisotropic nature of the substrate removes the degeneracy of the fundamental pair modes which are degenerate in an asymmetric strip waveguide with isotropic substrates.