A Numerical Study on Helix Nanowire Metamaterials as Optical Circular Polarizers in the Visible Region

Broadband optical circular polarizers functioning in the visible region were developed based on structural design and numerical simulation using the finite-difference time-domain method. By properly selecting the parameters of helix nanowire metamaterials including metal materials, diameters of wires, numbers of helix-period, spacing of grids, lengths of helix-period, and diameters of helixes, we proposed a broadband optical circular polarizer using aluminium helix nanowire metamaterials on a silica substrate. The proposed polarizer can reach an extinction ratio above 39 : 1 and a transmission efficiency above 64% in the range from 410 to 790 nm.