Mie Resonances of Silicon Meta-Atoms at Visible Frequencies

Abstract

Mie resonances of cubic meta-atom arrays based on silicon-on-insulator (SOI) wafers are investigated at visible frequencies. The model takes into account cubic silicon resonators fabricated on a thick silica base. Transmission and reflection spectra as well as local electromagnetic fields are presented. It is shown that the first two Mie resonances, electric and magnetic dipole resonances, appear in the region of visible frequency band (around 520 nm). Electromagnetic field is enhanced in silicon resonators when Mie resonances happen. Due to the low loss characteristic of silicon, the dielectric absorption is small and scattering contributes most to the light extinction. It is found that light transmission through meta-atom arrays can be dramatically suppressed by mirror effect of the two kinds of resonances. Reflection and transmission could be tailored at will by designing shapes of meta-atoms and lattice constants of periodic arrays, and electromagnetic transparency could be induced by interference between the two resonant states. In general, the meta-atoms provide potential applications in the field of optical metamaterials such as mirrors, metamaterial Huygens' surface, perfect absorbers, and subwavelength cavities.