Fig. 1. Schematic of metasurface. (a) Focused optical path diagram of RCP incidence on a metasurface; (b) optical path diagram of keeping wavefront for LCP incident on a metasurface

Fig. 2. Metasurface nanoblock unit and phase change and polarization conversion efficiency diagram of the function for d_x and d_y. (a) Structure composition diagram of periodic element; (b) phase change resulted from nanoblock depending on different sizes; (c) polarization conversion efficiency resulted from nanoblock dependent on different sizes

Fig. 3. Metalens view. (a) Top view; (b) local perspective view

Fig. 4. Simulation results of metalens as focusing lens under RCP incidence. (a) Intensity distribution at x-z plane; (b) intensity distribution at x-y plane when z=10 μm

Fig. 5. Simulation results of metasurface keeping wavefront under LCP incidence. (a) Phase distribution of x-z plane in transmission field; (b) optical field distribution of x-z plane in transmission field

Fig. 6. Comparison of the output light intensity under RCP or LCP incidence. (a) Light intensity along z-axis at optical output field of x=0 μm, y=0 μm; (b) light intensity along x-axis at optical output field of z=10 μm