Fig. 1. Optical path to calculate the off-axis aberration of the metalens with hyperbolic phase

Fig. 2. OPD curve when the distance from the stop to the metalens L is f /2

Fig. 3. Optical system with two metalenses symmetrically placed

Fig. 4. Optimized optical system

Fig. 5. MTF of the optical system

Fig. 6. Spot diagram of the optical system

Fig. 7. Distortion curves of the optical system

Fig. 8. Field and astigmatic curves of the optical system

Fig. 9. Schematic diagram of concentric-nanoring metalens

Fig. 10. Minimum linewidth of a metalens

Fig. 11. Fabrication flow chart of the metalens

Fig. 12. The local SEM image of metalens

Fig. 13. The optical mechanical structure design

Fig. 14. Assembled miniature fluorescence microscope

Fig. 15. The performance test platform for the system

Fig. 16. The resolution of the central field of view of the optical system

Fig. 17. The resolution of the edge field of view of the optical system

Fig. 18. Distortion of the optical system