Fig. 1. Structure of the proposed Fresnel lens

Fig. 2. Zooming principle of the proposed Fresnel lens

Fig. 3. Fabrication process and sample of the Fresnel lens

Fig. 4. Liquid interface of the Fresnel lens driven by different voltages

Fig. 5. Experimental setup used for the focal length measurement

Fig. 6. Principle and experimental results of the focal length measurement of the Fresnel lens

Fig. 7. Relationship between the focal length of the Fresnel lens and the driving voltage