Electromagnetic surface waves guided by the planar interface of isotropic chiral materials

The propagation of electromagnetic surface waves guided by the planar interface of two isotropic chiral materials, namely materials 풜 and ℬ, was investigated by numerically solving the associated canonical boundary-value problem. Isotropic chiral material ℬ was modeled as a homogenized composite material, arising from the homogenization of an isotropic chiral component material and an isotropic achiral, nonmagnetic, component material characterized by the relative permittivity 휀ℬ푎. Changes in the nature of the surface waves were explored as the volume fraction 푓ℬ푎 of the achiral component material varied. Surface waves are supported only for certain ranges of 푓ℬ푎; within these ranges only one surface wave, characterized by its relative wavenumber 푞, is supported at each value of 푓ℬ푎. For Re{휀ℬ푎}>0, as |Im{휀ℬ푎}| increases surface waves are supported for larger ranges of 푓ℬ푎 and |Im{푞}| for these surface waves increases. For Re{휀ℬ푎}<0, as Im{휀ℬ푎} increases the ranges of 푓ℬ푎 that support surface-wave propagation are almost unchanged but Im{푞} for these surface waves decreases. The surface waves supported when Re{휀ℬ푎}<0 may be regarded as akin to surface-plasmon-polariton waves, but those supported for when Re{휀ℬ푎}>0 may not.