Fig. 1. Element structures before and after rotating θ angle in Cartesian coordinate system

Fig. 2. Structural diagram of single-layer double-arrow unit. (a) Top view; (b) side view

Fig. 3. Reflection amplitudes and reflection phases at different frequencies. (a) Reflection amplitudes; (b) reflection phases

Fig. 4. Reflection amplitudes and reflection phases of different incident circular polarized light. (a) (b) Left-handed incident circular polarized light; (c) (d) right-handed incident circular polarized light

Fig. 5. Reflective metasurfaces based on single-layer double-arrow element structure at different topological charges. (a) l=1; (b) l=2

Fig. 6. Reflection phases and reflection amplitudes of vortex beams generated by metasurface at different frequencies when l=1

Fig. 7. Reflection phases and reflection amplitudes of vortex beams generated by metasurface at different transmission distances when l=2