In this paper, comprehensively utilizing the diffraction theory and electromagnetic resonance effect is creatively employed to design a multifunctional metasurface zone plate (MMZP) and achieve the control of polarization states, while maintaining a broadband achromatic converging property in a near-IR region. The MMZP consists of several rings with fixed width and varying heights; each ring has a number of nanofins (usually called meta-atoms). The numerical simulation method is used to analyze the intensity distribution and polarization state of the emergent light, and the results show that the designed MMZP can realize the polarization manipulation while keeping the broadband in focus. For a specific design wavelength (0.7 μm), the incident light can be converted from left circularly polarized light to right circularly polarized light after passing through the MMZP, and the focusing efficiency reaches above 35%, which is more than twice as much as reported in the literature. Moreover, the achromatic broadband focusing property of the MMZP is independent with the polarization state of the incident light. This approach broadens degrees of freedom in micro-nano optical design, and is expected to find applications in multifunctional focusing devices and polarization imaging.

With the rapid development of laser processing and infrared imaging, the demand for flat-top beams with high uniformity has become increasingly urgent. Conventional beam-shaping techniques based on bonded aspheric lenses are inherently bulky and inflexible, which limits their compatibility with modern optical systems. In this work, we propose a dielectric metasurface for laser beam shaping operating at 1064 nm, where the target phase distribution is derived by the given initial phase and is represented by a hyperbolic phase. An inverse optimization algorithm is proposed to optimize the unit cell consisting of silicon carbide (SiC) nanopillars and the silicon dioxide (SiO₂) substrate. Numerical results show that, after transmission through the designed metasurface, the beam forms a circular flat-top spot with a radius of 2 μm at the target plane, exhibiting an intensity uniformity of 0.1021 and an energy efficiency of 76.3%. This study offers a compact and highly efficient solution for the flat-top beam shaping, demonstrating significant potential for applications in precision-laser processing, optical trapping, and bioimaging.