Retrieving effective parameters for quasiplanar chiral metamaterials

We introduce and compare two approaches for retrieving quantitatively the effective chirality of metamaterials at normal incidence. The retrieval employs either the reflected and transmitted amplitude of a plane wave illuminating a finite three-dimensional (3D) metamaterial or the dispersion relation of the pertinent Bloch modes in an infinite metamaterial. Both approaches are applied to characterize a 3D metamaterial consisting of a stack of metallic gammadions separated by dielectric films. It will be shown that the results coincide if transitional effects between the metamaterial and the environment can be neglected.