%0 Journal Article
%T Broadband chiral metamaterials with large optical activity
%A Kirsty Hannam
%A David A. Powell
%A Ilya V. Shadrivov
%A Yuri S. Kivshar
%J Physics
%D 2014
%I arXiv
%R 10.1103/PhysRevB.89.125105
%X We study theoretically and experimentally a novel type of metamaterial with hybrid elements composed of twisted pairs of cross-shaped meta-atoms and their complements. We reveal that such two-layer metasurfaces demonstrate large, dispersionless optical activity at the transmission resonance accompanied by very low ellipticity. We develop a retrieval procedure to determine the effective material parameters for this structure, which has lower-order symmetry ($\mathrm {C}_4$) than other commonly studied chiral structures. We verify our new theoretical approach by reproducing numerical and experimental scattering parameters.
%U http://arxiv.org/abs/1401.8032v1