Tunable Multifunctional Terahertz Coding Metasurface for Polarization Manipulation

Coding metasurfaces (CMs) exhibit powerful capabilities in manipulating electromagnetic waves. Although conventional CMs are capable of manipulating both linearly polarized (LP) and circularly polarized (CP) waves, the Pancharatnam–Berry phase methods for controlling CP waves lead to inherent limitations, such as the inability to independently manipulate copolarized components and the functional locking between the two orthogonal CP waves. Herein, a tunable multifunctional terahertz (THz) metasurface integrated with vanadium dioxide (VO2) is demonstrated to manipulate LP waves by the propagation phase and CP waves by hybrid phase. The required phase profiles are obtained by changing the length of the VO2, the cross‐shaped ellipse, and its rotation angle separately. The proposed design strategy can overcome the above limitations at different frequencies. As a proof‐of‐concept demonstration, four metasurfaces are constructed to achieve dynamic switching between dual‐beam and single‐beam by the insulator–metal phase transition of VO2, as well as anomalous reflection, vortex beams, focused vortex beams, and absorber regardless of the insulating and metallic state of VO2. This multifunctional CM has great potential in THz wireless communications.