Generation of steep phase anisotropy with zero-backscattering by arrays of coupled dielectric nano-resonators

The interaction of light with high-permittivity dielectric nano-resonators can lead to zero-backscattering (i.e., full transmission), attributed to the simultaneous excitation of electric and magnetic dipolar modes in these resonators. In this paper, we numerically demonstrate that 2-dimensional Si nanocuboid arrays with anisotropic periodicity and finely tuned cuboid height can generate up to 2 pi optical phase anisotropy with zero-backscattering. Especially, by introducing strong Fano-type coupling into unit cells of the array, the induced phase anisotropy becomes ultra-steep with excitation wavelength. These special optical properties promise applications in various transmissive photonic devices, and we discuss their potential applications in transmissive polarization conversion and sensing. (C) 2014 AIP Publishing LLC.