Fig. 1. Schematic diagram of metalens. (a) Schematic diagram of achromatic metalens dispersion; (b) schematic diagram of metalens focusing

Fig. 2. Schematic diagram of metalens unit structure

Fig. 3. Phase distribution and transmission of unit structure with r=0.05-0.35 μm,H=6 μm,and p=0.8 μm. (a) Phase distributions with wavelengths of 3.00, 3.25, and 3.50 μm, respectivly; (b) transmission with wavelengths of 3.00, 3.25, and 3.50 μm, respectivly; (c) phase distributions with wavelengths of 3.75, 4.00, and 4.25 μm, respectivly; (d) transmission with wavelengths of 3.75, 4.00, and 4.25 μm, respectivly; (e) phase distributions with wavelengths of 4.50, 4.75, and 5.00 μm, respectivly; (f) transmission of wavelengths of 4.50, 4.75, and 5.00 μm, respectivly

Fig. 4. Field strength diagram of achromatic metalens at full wavelengths

Fig. 5. FWHM curves of discrete wavelengths. (a) FWHM curves of wavelengths of 3.00, 3.25, and 3.50 μm, respectively. (b) FWHM curves of wavelengths of 3.75, 4.00, and 4.25 μm, respectively. (c) FWHM curves of wavelengths of 4.50, 4.75, and 5.00 μm, respectively

Fig. 6. Field intensity distribution at focuses of discrete wavelengths under circularly polarized light

Fig. 7. Focal length curves of three kinds of polarized incident light at different wavelengths

Fig. 8. Focusing efficiency at discrete wavelengths