Fig. 1. Silicon-based metalens. (a) Schematic diagram of silicon-based metaatoms; (b) Schematic diagram of the focusing

Fig. 2. Flowchart of the optimization process to achieve super-resolution focusing with weak sidelobes

Fig. 3. Theoretical results of silicon-based metalens. (a) Two-dimensional intensity distribution in the focal plane; (b) The corresponding intensity curve in the focal plane; (c) Two-dimensional intensity distribution on xz plane; (d) Intensity (red), FWHM (blue), and SR (green) parameter on the xz plane

Fig. 4. FDTD simulation results of silicon-based metalens. (a) Two-dimensional intensity distribution in focal plane; (b) Focal plane intensity curve; (c) Two-dimensional intensity distribution on xz plane; (d) Focal spot intensity (red), FWHM (blue) and SR (green) parameter curves on the xz plane

Fig. 5. The SEM and experimental schematic of metalens. (a) The SEM of the metalens; (b) Experimental schematic based on optical microscopy system with a large numerical-aperture objective

Fig. 6. Experimental results of silicon-based metalens on the focal plane. (a) Two-dimensional intensity distribution on the focal plane; (b) The corresponding intensity curves along the x-axis (green) and y-axis (blue), mean intensity curves (red) and the design results (black)

Fig. 7. Experimental (red) and design (green) results of silicon-based metalens on the xz plane. (a) Two-dimensional Intensity distribution on the xz plane; (b) The corresponding intensity; (c) FWHM; (d) Sidelobe ratio