Multiple surface electromagnetic waves guided by the planar interface of a rugate filter and a hyperbolic columnar thin film

A canonical boundary-value problem was solved to analyze surface electromagnetic waves (SEWs) guided by the planar interface of a rugate filter and a hyperbolic columnar thin film (CTF). A dispersion equation was solved to study the characteristics of the SEWs. Numerical results showed that multiple surface waves of the same frequency but of different phase speeds, polarization states, degrees of localization, and field profiles can be excited at the interface. The number of SEWs depend upon the period of the rugate filter and the direction of propagation with respect to the morphologically significant plane of the hyperbolic CTF.