Fano Resonant Cuboidal Dielectric Nanoantennas

Abstract

In this paper, we report Fano resonance in the dielectric disk and rod cuboidal nanoparticles. In these nanoparticles, forward to backward scattering ratio is enhanced as compared to cubic or other symmetrical nanoparticles. Electric and magnetic dipole resonances come closer by tailoring the dimensions of cuboidal nanoparticles so that both of them spectrally overlap and on-resonance scattering of electric and magnetic dipole moments take place in the visible region. Broad electric dipole and narrow magnetic dipole act as bright and dark modes, respectively. Interaction of these modes generate Fano dip in the backward scattering and enhancement in the forward scattering leading to the improvement in directivity and radiation efficiency which can be used for the design of highly directional nanoantennas in the visible region.