Far-Field Analysis on Reflecting Colors of Dielectric Nanosphere Metasurface

Photonic resonances in nanostructures have been exploited in reflective or transmission color filters, which can provide vivid colors. Metallic nanostructures have been widely studied to demonstrate a variety of color filters based on strong light interaction due to plasmonic resonances. However, because of the severe absorption loss of metal in visible light, dielectric nanoparticles having Mie resonances are a popular study focus in recent years to achieve vivid colors. In contrast to the behaviors of point-like electric dipole in metallic nanoparticle, the interplay of the electric and magnetic Mie resonances in dielectric nanoparticle enables a large degree of freedom in manipulating the directivity of light scattering, reflecting/transmitting color, and spontaneous emission rates. Here, we propose a color reflector based on an array of silicon nanoparticles that shows reflectance greater than 70% and vivid colors over the entire visible spectrum range, which covers sRGB color area. Viewing angle dependencies of the color and brightness are also investigated by calculating color-resolved far-field patterns, while exhibiting maintenance of the color and high reflectance over a broad viewing angle.