Abstract

The main experimental results that have been recently obtained for the linear and nonlinear opticalresponses of ordered two-dimensional arrays of planar chiral metallic nanostructures are considered. Theseexperimental results demonstrate that the polarization state of the linear and nonlinear optical responses ofmetasurfaces are substantially determined by the chirality of a single nanoelement and the related spatial dis-tribution of the optical second harmonic generation intensity. As a result, circular dichroism effects appear inthe linear and nonlinear optical responses of a chiral metasurface. The anisotropy of the second harmonic isexperimentally shown to play a substantial role in the effects of extrinsic chirality, which is determined by thespatial symmetry of an array of nanoelements. The main properties of circular dichroism in the quadraticoptical response are supported by numerical calculations and symmetry analysis of structures.