Polarization-Tunable Broadband Terahertz Emission from Ferromagnetic Heterostructure Metasurfaces

Terahertz (THz) waves exhibit great potential in imaging, communication, and biosensing, yet conventional devices face challenges in simultaneously achieving efficient broadband THz generation and precise polarization control. Here, we present a ferromagnetic heterostructure metasurface fabricated by direct laser writing. By variation of the magnetic field angle, reversible switching between left- and right-handed circularly polarized THz waves is realized. We further reveal the quantitative relationship between stripe parameters and THz performance, providing critical guidelines for the design of THz functional devices. Our experimental results unambiguously demonstrate that the ferromagnetic heterostructure metasurface serves as a robust and scalable platform for advanced THz wave manipulation, offering a solution to the limitations of conventional THz systems and paving the way toward next-generation integrated THz devices.