Fig. 5. Spin-controlled generation of hybrid-order Poincaré sphere beams.

a Illustration of the two subarrays to be merged into the combined metasurface. Subarray A and subarray B are responsible for the generation of the OAM modes |L, l = 3> and |R, l = 1>, respectively. b SEM image of the central part of the combined metasurface. Scale bar: 500 nm. c Experimental demonstration of the spin-controlled hybrid superposition of the OAM modes |L, l = 3> and |R, l = 1> at 820 nm. L or R in the bracket indicates a spin state of LCP or RCP, while l is the topological charge of the vortex beam corresponding to an OAM of l$\hslash$. The polarization states of the incident beam are RCP, right-handed elliptically polarized, linearly polarized, left-handed elliptically polarized, and LCP from left to right. The superimposed mode is investigated by inserting a horizontal linear polarizer before the CCD, as indicated by the white double-headed arrow. d Captured intensity profiles of the hybrid-order Poincaré sphere beams under x-polarized and y-polarized incidence after passing through a rotating linear polarizer. The incident polarization is denoted by the red double-headed arrow, and the transmission axis of the linear polarizer is indicated by the white double-headed arrow