Substrate-induced bianisotropy in plasmonic grids

In this paper we consider the effect of so-called substrate-induced bianisotropy for optically dense grids of plasmonic nanoparticles, e. g. ellipsoids, located on a refractive interface. Such grids, referring to the class of plasmonic island films, are used in spectroscopic studies, for the enhancement of solar cells, etc. We develop the homogenization model of such grids and show that in the case of highly refractive (semiconductor) substrates the homogenized response must include the bianisotropic component. With explicit examples we show that the retrieved parameters describing this response properly characterize the optical properties of such grids.