Polarization management based on dipolar interferences and lattice couplings.

Abstract

We have achieved efficient polarization manipulations based on dipolar interferences and lattice couplings in one-dimensional cylindrical metalattices. First, we employ the scattering asymmetry factor g to quantify the directional scattering ability and find the maximum |g|max=1/2 for a cylinder with effective excitations of electric and magnetic dipoles simultaneously. Further, the strong negative-g (gp = -0.38) for p-polarization and positive-g (gs = 0.68) for s-polarization are obtained within a narrow visible band using c-Si with experimental data. Inspired by the polarization-dependent phenomena, we design a metalattice-based linear polarizer considering lattice effects with an optimal particle arrangement. The metalattice performs near-perfect reflection for p-polarized waves but with zero reflection for s-polarized waves with large extinction ratios for transmission (17 dB) and reflection (24 dB). The perfect functionalities can be attributed to the near-field lattice couplings with dipolar interferences. And, we reveal that the polarization-dependent scattering coefficients, which are sensitive to the lattice period, can be largely tuned owing to lattice effects, therefore contributing to modifying far-field scattering patterns. More specifically, the proposed linear polarizers also show robust and reliable functionalities when considering lattice imperfections, the effects of system sizes, oblique incident angles, and the tunbility for different working wavelengths. The present study paves a way to stimulate many advanced practical implements based on multipolar interferences and lattice couplings.