Complex media characterized by chirality and negative refractive index: analysis and applications

摘要

Inclusions embedded in conventional positive refractive index materials are used to fabricate artificial materials, with negative permittivity, permeability and negative refractive index (NRI). We consider electromagnetic wave propagation in NRI materials with chiral properties that are not negligible. To this end we initially derive explicit expressions for reflection and transmission matrices for a chiral slab. The diagonal terms of the linearly polarized reflection coefficient matrix are the familiar Fresnel reflection coefficients, and the off-diagonal, cross-polarized reflection coefficients are proportional to the chiral parameter and the product of the vertically and horizontally polarized transmission coefficients of the non-chiral host medium. The-full wave modal expansion of the fields include evanescent and propagating radiation fields, several types of lateral waves associated with the phenomena of total internal "backward" reflection as well as several different surface waves (plasmons). Using NRI materials with chiral properties it is possible to fabricate rectangular slabs that perform as lenses associated with two focal lines at the opposite side of the source. Furthermore, the backward propagating lateral waves could be used to make the chiral metamaterials perform like reflectors.