Fig. 4. Multifunctional metasurface devices enabled by independent amplitude and phase control for orthogonal polarization states.

a, b Experimental demonstration of chirality-dependent cylindrical lens line focusing with nonuniform intensity distribution. The device is designed to focus RCP and LCP light to a line along the x-direction (right of a) and y-direction (right of b), along with a brightness gradient, at a focal length of ~0.5 and 1.0 mm, respectively. c, d Cross-sections of the measured RCP and LCP line foci along the x- and the y-directions (denoted by two white arrows of a and b), respectively. Insets: intensity distributions of the middle of measured RCP and LCP line foci along y- and x-directions (denoted by dashed white lines of a and b). e, f Experimental demonstration of polarization-dependent complex-amplitude holograms. Right: experimental and calculated intensity distributions of far-field hologram images of “Penrose triangle” for x-polarized light (e) and “Mobius strip” for y-polarized light (f). Scale bar: 200 μm. Experimental images were obtained at a propagation distance of z ≈ 5 mm