Efficient Polarization Beam Splitter Based on All-Dielectric Metasurface in Visible Region

In this paper, we present an all-dielectric gradient metasurface, composed of periodic arrangement of differently sized cross-shaped silicon nanoblocks resting on the fused silica substrate, to realize the function of polarization split in visible region. The cross-shaped silicon block arrays can induce two opposite transmission phase gradients along the x-direction for the linear x-polarization and y-polarization. By properly designing, the metasurface can separate the linearly polarized light into x- and y-polarized ones, which propagate at the same angle along the left and right sides of the normal incidence in the x-z plane. Particularly, when a beam with the polarization angle of 45.0° is incident on the proposed device, the x- and y-polarized transmitted ones possess nearly equal intensity within the wavelength range from 579 to 584 nm. We expect the proposed polarization beam splitter can play an important role for future free-space optical devices.