Figure 1.

(a) Schematic of the unit-cell structure with P_x = P_y = 250 nm. The flat lens consists of TiO₂ nanofins on an Ag mirror. The nanofin can rotate in the x-y plane with an angle θ to create a required phase according to the Pancharatnam-Berry phase. The nanofin have length L = 190 nm, width W = 90 nm and height h₁ = 600 nm. The Ag film has thickness of h₂ = 150 nm. (b) Calculated reflection coefficients for x- and y-polarized light and (c) their phase φ_x, φ_y and phase difference Δφ. (d) Calculated reflectivity of the cross-polarization and co-polarization for the designed hybrid structure.