Response of slanted chiral sculptured thin films to dipolar sources

A theoretical investigation of the electromagnetic response of a slanted chiral sculptured thin film (STF) to dipolar sources is presented. Dyadic Green functions (DGFs) for a slanted chiral STF sandwiched between two vacuous half-spaces are formulated as planewave angular spectrums. First, the response of the slanted chiral STF to obliquely incident plane waves is obtained by rigorous coupled-wave analysis implemented with a stable algorithm, then, asymptotic evaluation of the DGFs is carried in the far-field limit. The radiation patterns of Beltrami source configurations close to a slanted chiral STF are computed and discussed. In particular, certain characteristic features - which are closely related to the circular Bragg phenomenon - in the radiation patterns are found to be spatially asymmetric, because of the effective transverse periodicity of the chosen thin film. (C) 2004 Elsevier B.V. All rights reserved.