VO2-enabled reconfigurable terahertz metasurface for Airy beam generation and OAM multiplexing.

With the continuous advancement of 6G communication technology, the development of the terahertz (THz) frequency band has become a significant trend. Metasurface designs are increasingly applied in the terahertz domain with more diverse functionalities. As an artificial structure capable of flexibly manipulating electromagnetic waves, metasurfaces offer new possibilities for terahertz communications. In particular, Airy beams, characterized by their self-healing and nondiffracting properties, are well-suited for stable transmission in complex environments; meanwhile, orbital angular momentum (OAM) multiplexing technology utilizes the angular-momentum degree of freedom of beams to effectively enhance communication capacity. Through metasurface technology, flexible switching between Airy beam and OAM multiplexing modes can be realized, providing efficient and diversified solutions for 6G communication systems. In this paper, we propose a terahertz metasurface based on vanadium dioxide (VO2). When VO2 is in two distinct physical states, the metasurface can respectively generate Airy beams in the 202 ∼ 212 GHz band and perform OAM multiplexing or other arbitrary modulations achievable by 3-bit phase coding within the 116 ∼ 130 GHz band. Furthermore, the functionalities of the metasurface are dynamically controlled by external voltage, demonstrating great potential for broader application scenarios.