Fig. 2. Hologram metasurface design and operation.

a Optimized pattern of HSQ ridges composing the polarization-splitting metasurface. b Illustration of the operation principle behind generation of orthogonally polarized beams: red and blue coloured areas indicate metasurface domains responsible for generating predominantly X- and Y-polarized outgoing waves, respectively. Grey coloured domains contribute to both X- and Y-polarized beams. Metasurfaces designed for generating either X-(red) or Y-(blue) polarized beams are illustrated in (c). d Calculated 3D angular distributions of the superimposed beam intensity shown by height and polarization Stokes parameter S₁ encoded by colour. The angular coordinates k_x/k₀ and k_y/k₀ are x- and y- wavevector projections on the image plane normalized to the free space wavevector. These simulations are conducted for the optimized metasurface configuration described further in the paper. The occurrence of blue and red peaks demonstrates spatial separation of two emission channels featuring orthogonal linear polarizations.