Broadband terahertz metasurfaces for anomalous reflection and vortex beam generation

This paper presents a broadband terahertz (THz) meta-atom composed of copper and polyimide, capable of efficient wavefront modulation. By leveraging the Pancharatnam–Berry phase mechanism, the meta-atom achieves full 0–2π phase coverage across a wide frequency range of 1.6–3.2 THz under circularly polarized wave illumination through the rotation of its top metallic structure. Based on this design, we further demonstrate three types of broadband metasurfaces by strategically arranging the meta-atoms, achieving anomalous reflection, orbital angular momentum (OAM) generation, and deflected OAM generation, respectively. The proposed broadband THz metasurfaces hold significant potential for advanced applications in quantum communication and optical sensing systems.