Terahertz four-channel polarization-multiplexed vortex beams based on vanadium dioxide integrated metasurfaces
Runxuan Zhang, Ruixing Nie, Zijun Chen, Jinhui Chen, Zhengyong Song
Abstract
• Anisotropic meta -atoms are designed for the generation of four-channel vortex beams via a single metasurface. • Functions of metasurfaces are dynamically adjusted by altering the polarization of incident wave and the state of VO 2 . • The generated vortex beams own contrasting OAM modes, quantities, and deflection directions. In recent years, vanadium dioxide (VO 2 ) has drawn enormous attention in dynamic electromagnetic (EM) manipulation, owing to its mild phase change condition and prominent diversity of optical characteristics. In this paper, anisotropic meta -atoms integrating VO 2 are proposed to obtain four polarization-multiplexing channels. The meta -atom is composed of two stacking metal–insulator–metal (MIM) structures. For the modulation of EM wavefront in desired manners, a meta -atom database composed of 256 meta -atoms is elaborately designed. Applying the meta -atom database and the degree of freedom in interfacial phase distribution, two metasurfaces are demonstrated in the verification of four-channel polarization-multiplexed vortex beams. The firstly proposed metasurface realizes the generation of four vortex beams with different topological charges. Each channel is dependent on the polarization of the incident wave and VO 2 state. The further investigated metasurface achieves simultaneous control over the reflection direction, quantity, and mode of vortex beams under different VO 2 states and polarization states of incident wave. In addition, designed metasurfaces exhibit wideband effect for over 100 GHz. The proposed design method enables four-channel generation of vortex beams using a single metasurface, and may have potential applications in dynamic and integrated terahertz communication.