Fig. 1. Metasurface element and array model. (a) Metasurface element and structured light; (b) schematic of metasurface element layer structure; (c) schematic of spatially encoded structured light control

Fig. 2. Schematic of metasurface element. (a) Front view of metasurface element; (b) side view of metasurface element

Fig. 3. Coding and equivalence diagrams of metasurface elements. (a) Structured light point source and photosensitive Ge position coding; (b) metal split ring equivalence diagram

Fig. 4. Principle of the polarization convertor

Fig. 5. Amplitude and phase characteristics of 2 bit metasurface element. (a)-(d) Schematic of the excited state of the photoconductive Ge to form 2 bit code; (e)-(h) schematic of the excited state of structured light to form 2 bit code; (i)-(l) normalized electric field diagram at the intersection of the metal split ring and the dielectric; (m) amplitude and (n) phase response of metasurface element at different excitation states

Fig. 6. Metasurface beam splitting characteristics. (a)-(d) Simulated far-field scattering patterns of the metasurface with four coding sequences; (e)-(h) electric field at y=0 cross-section for the far-field beams of four encoding methods; (i)-(l) schematic of the metasurface element layout method, and all metasurface arrays have 18×18 elements

Fig. 7. Single-beam anomalous reflection characteristics of the metasurface. (a)-(c) Simulated far-field scattering patterns of the metasurface with three coding sequences; (d)-(f) electric field at y=0 cross-section for the far-field beams of three encoding methods; (g)-(i) array coding schematic of three encoding methods, and all metasurface arrays have 20×20 elements

Fig. 8. Encoded metasurface generation of beams carrying OAM. (a)-(c) Far-field patterns of l=1, l=2, and l=3 metasurface encoding generation of vortex light; (d)-(f) generated vortex beam amplitude; (g)-(i) generated vortex beam phase; (j)-(l) far field at the x=0 cross-section of vortex beam; (m)-(o) schematic of three orders of vortex beam metasurface encoding