Fig. 1. Diagram of Fresnel lens array

Fig. 2. Schematic of Fresnel lens

Fig. 3. Design flow diagram of Fresnel lens

Fig. 4. Ray tracing diagram of Fresnel lens after optimization of 15th annulus shape

Fig. 5. Spot sequence diagram of 15th annulus of Fresnel lens

Fig. 6. Designed lens annulus spot diameters

Fig. 7. Simulation analysis of beam convergence performance of Fresnel lens

Fig. 8. Simulation diagrams of Fresnel lens receivers. (a) Receiver A; (b) receiver B

Fig. 9. Convergent spot diameters of different annuluses under influence of tolerance

Fig. 10. Fresnel lens processing physical picture

Fig. 11. Schematic of detection optical path of energy transmittance

Fig. 12. Spot diameter measurement

Fig. 13. Experimental diagram of energy coupling efficiency

Fig. 14. Focusing spot at 670 mm from Fresnel lens

Fig. 15. Spectral signal intensities at different positions