SURFACE ELECTROMAGNETIC WAVES GUIDED BY INTERFACES WITH ISOTROPIC CHIRAL AND UNIAXIALLY CHIRAL MATERIALS

Abstract

The electromagnetic waves that propagate along the interface of two dissimilar ma terials are called surface waves. The surface plasmon-polariton (SPP) waves are the surface waves that are guided by an interface of the partnering plasmonic material. The surface waves propagate parallel to the interface and decay away from the inter face. The surface waves also decay along the direction of propagation if one or both of the partnering materials are lossy. The main purpose of this thesis is to theoretically investigate the propagation and excitation of the SPP waves with isotropic chiral materials and uniaxially bianisotropic chiral materials. Firstly, the characteristics of the SPP waves with these materials are reported by investigations of the canonical boundary-value problems where both partnering materials are taken to fill up the half-spaces. Afterwards, the excitation of these SPP waves is shown with both types of prism-coupled configurations, i.e., the Turbadar—Kretschmann—Raether (TKR) configuration and the Turbadar—Otto configuration. The effects of the complex valued chirality parameter on the SPP-waves excitation are also investigated. Three basic problems are solved numerically in this thesis. The first deals with finding the characteristics of surface waves propagating along the interface of two isotropic chiral materials. The second problem deals with the interface of isotropic chiral material and a plasmonic material. After developing an understanding of the isotropic chiral medium, I moved on to investigate the SPP-waves excitation with the interface of uniaxially chiral bianisotropic material and a plasmonic material. The SPP waves propagating along the interface of isotropic chiral material and a plasmonic material were found to exist only when the chirality was smaller than a xxv xxvi threshold value. These waves could be excited using both prism-coupled configura tions, though the Turbadar—Otto configuration was found better than the TKR in delineating the excitation of the SPP waves. For the uniaxially chiral, bianisotropic materials, similar phenomenon was observed where the SPP waves could exist only when the chirality pseudoscalar was less than a threshold value. Though, this thresh old value in the bianisotropic material can be tuned by changing other parameters of this material. The SPP waves studied in this thesis can be used for designing optical sensors to sense chirality of the materials. Furthermore, the existence of threshold value can be used to design plasmonic switches. Also, the finding of hybrid polarized SPP waves with chiral materials can be useful for optical circuits