Light guiding and switching using eccentric core-shell geometries.

High Refractive Index (HRI) dielectric nanoparticles have been proposed as an alternative to metallic ones due to their low absorption and magnetodielectric response in the VIS and NIR ranges. For the latter, important scattering directionality effects can be obtained. Also, systems constituted by dimers of HRI dielectric nanoparticles have shown to produce switching effects by playing with the polarization, frequency or intensity of the incident radiation. Here, we show that scattering directionality effects can be achieved with a single eccentric metallo-HRI dielectric core-shell nanoparticle. As an example, the effect of the metallic core displacements for a single Ag-Si core-shell nanoparticle has been analyzed. We report rotation of the main scattering lobe either clockwise or counterclockwise depending on the polarization of the incident radiation leading to new scattering configurations for switching purposes. Also, the efficiency of the scattering directionality can be enhanced. Finally, chains of these scattering units have shown good radiation guiding effects, and for 1D periodic arrays, redirection of diffracted intensity can be observed as a consequence of blazing effects. The proposed scattering units constitute new blocks for building systems for optical communications, solar energy harvesting devices and light guiding at the nanoscale level.