Dual-band broadband terahertz orbital angular momentum metasurface

In this paper, we propose and experimentally demonstrate a dual-band, broadband Terahertz-orbital angular momentum (THz-OAM) electromagnetic (EM) metasurface (MS) capable of independently generating OAM beams of different modes in two distinct terahertz bands simultaneously. Through simulations, fabrication, and testing of the MS, we demonstrate that the MS generates THz-OAM EM waves with mode l = + 1 in the frequency range of 125–135 GHz and mode l = −1 in the range of 160–170 GHz, without interference. The proposed MS exhibits several advantageous characteristics, including dual-band operation, large bandwidth, high integration, low cost, and polarization insensitivity. These features make it highly valuable for various applications and hold significant importance for the development of the next generation of large-capacity and high-speed communication.