Fig. 1. Comparison of the polarization controls based on the birefringence and dichroism metasurfaces.

a Schematic of conventional polarization control based on a cascaded linear polarizer and birefringent single-meta-atom metasurface. The incident beam with well-defined polarization was converted to arbitrary polarization states by imparting different phase retardations on orthogonal linear polarizations along the fast and slow axes of the birefringent meta-atom. b Schematic of the proposed all-in-one polarizer that can function at an arbitrary position on the Poincaré sphere by design based on a dielectric metasurface composed of dimerized nanopillars, which can directly operate with unpolarized incident light and generate arbitrary polarization states, including linear, elliptical and circular polarizations, regardless of the incident polarization state.