Abstract:The zoom system can achieve continuous optical zoom, and achieve continuous imaging of targets with different depths of field. It has wide application and development potential in the fields of focal depth extension and optical inspection. This paper proposes a compact and flat phase diffractive element that can realize continuous focusing function, and design, analyze and verify this kind of phase-type zoom diffractive element that can realize lateral modulation. Through the basic theoretical model of scalar diffraction and the design method of Fresnel band and multi-step phase diffractive element, the simulation and experimental verification of key components of lateral zoom are realized. And based on the multi-wavelength response spatial light modulator, the device phase modulation verification experimental system was built that prove the modulation capability. The results of the experimental simulation tests show that the key components can achieve effective modulation of the lateral zoom, and the zoom ratio can reach the designed 5 times zoom target.