Scattering directionality of high refractive index dielectric particles: a note for solar energy harvesting

Abstract

Subwavelength metallic nanoparticles have been proposed for optimizing efficiency of current solar cells. However, their inherent ohmic losses limit their performance. High Refractive Index dielectric particles have been suggested as an alternative to metallic ones due to their low-losses in the visible and near infrared spectral regions and also to their magnetic response. The directionality properties that arise from the coherence effects between electric and magnetic resonances, make them very attractive for redirecting the incident radiation. In this work, we analyze the Scattering Directionality Conditions of a symmetric dimer made of High Refractive Index dielectric particles as a function of the gap. We demonstrate that, by using a dimer, it is possible to find, in the dipolar regime, two spectral regions where the incident radiation is redirected in the forward direction. They correspond to the Zero-Backward condition (also observed for isolated particles) and to a “near Zero-Backward” condition. The last would correspond to a “rotation” of the near Zero-Forward condition as a consequence of the interaction effects between the dimer components. The proposed scattering unit could constitute a new block for building more complex systems for applications in optical communications, light guiding and solar energy harvesting devices.