Dynamic Multifunctional Metasurface for Terahertz Holography, Vortex, and Grayscale Imaging

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.