ABSTRACT Metasurfaces offer unprecedented capabilities for manipulating electromagnetic wave, but simultaneous and independent generation of diverse functionalities like holography, orbital angular momentum (OAM), and grayscale imaging (GI) within a single platform remains a challenge. Here, we demonstrate a terahertz bilayer metasurface. It leverages insulator‐metal phase transition of vanadium dioxide (VO 2 ) for dynamic control. The metasurface integrates spin‐decoupled theory and Malus’ law to achieve multifunctional wavefront engineering. As VO 2 is metallic, a vortex beam (VB) with topological charge (TC) of l = 1 is gained under left‐handed circular polarization (LCP) incidence, while a distinct hologram image (HI) A is obtained under right‐handed circular polarization (RCP) incidence. Concurrently, GI 6 is observed in near field under x‐polarized incidence. As VO 2 is insulating, it dynamically reconfigures metasurface's response. HI H is generated in LCP channel, and VB with TC = −2 is formed in RCP channel. Meanwhile, GI 3 with x polarization appears in near field. Through rigorous numerical simulations, we validate independent control and high‐quality performance of each channel. This work demonstrates a versatile platform for achieving complex and switchable optical operations.
Chen et al. (Sun,) studied this question.