Vector beam generation based on spin-decoupling metasurface zone plate

As singular beams, vector beams with inhomogeneous polarization distribution have found extensive application prospects in many fields, including optical information processing, high-resolution imaging, and quantum optics. Metasurfaces with strong ability to manipulate the polarization and phase of electromagnetic waves have been harnessed to generate vector beams. Among them, the proposal of metasurfaces with different responses to orthogonally polarized waves can undoubtedly enhance the flexibility of optical device design. Here, we introduce the diffractive optics (Fresnel zone plates) into the spin-decoupling metasurfaces, called the metasurface zone plates, utilized to engender desired vector beams. As a demonstration, we design two metasurface zone plates: one can generate a focused vector beam under linearly polarized incidence, and the other is exploited to engender a vector vortex beam. The simulated and measured results simultaneously demonstrate the feasibility and practicability of such a concept. Our work unlocks the potential of optical devices and may further promote the development of metasurface polarizers toward miniaturization and versatility.