Vanadium dioxide-assisted terahertz metasurface for broadband polarization conversion and multi-mode vortex beam generation in full-spaceYupei Tang, You Li, Xunjun He and Ying ZhangEur. Phys. J. Plus, 140 5 (2025) 422DOI: https://doi.org/10.1140/epjp/s13360-025-06377-y