Dynamic Multi-Channel Beam Generation of Circularly Polarized Terahertz Waves Using Programmable Metasurface

The realization of dynamically controllable multi-channel beam generation presents a key research challenge in THz communication and imaging applications. In this work, we design a programmable metasurface composed of a gold-VO2 bilayer ring to achieve the dynamic multi-channel modulation in the THz band. Due to the insulator-to-metal transition (IMT) characteristics of$\text{VO}_{2}$, the unit cells are digitally encoded as “0” and “1”, corresponding to left-handed (LCP) to right-handed (RCP) circular polarization conversion and polarization preservation, respectively. Based on the polarization coding, the gradient phase is introduced to dynamically achieve the control of the beam number, polarization state, amplitude and abnormal reflection angle of the dynamic reflected beam. Multi-dimensional degree-of-freedom collaborative regulation will promote terahertz dynamic multi-beamforming, polarization multiplexing enhancement, and polarization detection.