Fig. 1. Schematic of proposed metalens. (a) Fragment; (b) Cross section view ; (c) Top view of proposed metalens

Fig. 2. Phase shift and reflectance of reflected wave of (a) x-polarization incidence and (b) y-polarization incidence

Fig. 3. Proposed metalens working for one focus. (a) Relationship between the position x and radius of each unit for x-polarization; (b) Simulated Poynting vector distributions for metalens for x-polarization; (c) Intensities of the focusing spots along x direction for x-polarization; (d) Relationship between position x and the radius of each unit for y-polarization; (e) Simulated Poynting vector distributions for the metalens for y-polarization; (f) Intensities of the focusing spots along the x direction for y-polarization

Fig. 4. Simulated Poynting vector distributions for the metalens with incidence wavelength of (a) 650 nm, (b) 700 nm, (c) 750 nm, (d) 900 nm, (e) 850 nm

Fig. 5. Intensities of the focusing spots along the x direction with the incidence wavelength of (a) 650 nm, (b) 700 nm, (c) 750 nm, (d) 850 nm, (e) 900 nm

Fig. 6. Proposed metalens working for daul focus. (a) Relationship between the position x and the radius of each unit; (b) Simulated Poynting vector distributions for the metalens; (c) Intensities of the focusing spots along the x direction

Fig. 7. Proposed metalens working for three focus. (a) Relationship between the position x and the radius of each unit; (b) Simulated Poynting vector distributions for the metalens; (c) Intensities of the focusing spots along the x direction