3D-Printed Linear-Polarization Multiplexed Metasurface for Independent Terahertz Focusing and Orbital Angular Momentum Beam Generation

We propose and experimentally demonstrate a dual-linear-polarization multiplexed metasurface capable of independently generating point-focused and focused orbital angular momentum (OAM) terahertz beams at 140 GHz. The metasurface consists of polymer-based birefringent meta-atoms fabricated via high-resolution 3D printing, enabling full 0–2$\pi$transmission phase control for both orthogonal polarizations through independent geometric parameter tuning. For y-polarized incidence, the device achieves a focal length of 82 mm with a high efficiency of 50.71%. For x-polarized incidence, it produces an focused OAM beam with a topological charge of$\ell$= –2 and a focal length of 115 mm, maintaining an efficiency of 54.61%. The measured focal positions, beam profiles, and phase structures exhibit strong agreement with full-wave simulations, with only minor deviations attributed to fabrication and measurement constraints. Compared with previously reported designs, the proposed all-resin structure offers simplified fabrication, single-layer multifunctional implementation, and high phase-control accuracy. This work demonstrates a scalable and low-cost strategy for multifunctional terahertz beam shaping and multiplexing, with promising applications in terahertz imaging, communication, and sensing.