title: Ubiquity of optical activity in planar metamaterial scatterers.
abstract: Recently it was discovered that periodic lattices of metamaterial scatterers show optical activity, even if the scatterers or lattice show no 2D or 3D chirality, if the illumination breaks symmetry. We demonstrate that such "pseudochirality" is intrinsic to any single planar metamaterial scatterer and in fact has a well-defined value at a universal bound. We argue that in any circuit model, a nonzero electric and magnetic polarizability derived from a single resonance automatically imply strong bi-anisotropy, i.e., magnetoelectric cross polarizability at the universal bound set by energy conservation. We confirm our claim by extracting polarizability tensors and cross sections for handed excitation from transmission measurements on near-infrared split ring arrays, and electrodynamic simulations for diverse metamaterial scatterers.
authors.affiliation: Center for Nanophotonics, FOM Institute for Atomic and Molecular Physics, Science Park 104, 1098 XG Amsterdam, The Netherlands. i.sersic@amolf.nl
authors.forename: Ivana
authors.initials: I
authors.lastname: Sersic
authors.forename: Marie Anne
authors.initials: MA
authors.lastname: van de Haar
authors.forename: Felipe Bernal
authors.initials: FB
authors.lastname: Arango
authors.forename: A Femius
authors.initials: AF
authors.lastname: Koenderink