Review of terahertz gradient metasurface

Abstract

Metasurface, a novel artificial electromagnetic material, its thickness is much smaller than the wavelength. By regulating the interaction between the sub-wavelength unit structure and the electromagnetic wave, the wave will undergo a phase or amplitude mutation after passing through the metasurface, so as to realize the regulation of the propagation direction, waveform and polarization mode of the electromagnetic wave. Compared with 3D metamaterials, the metasurface not only inherits the original ability of the electromagnetic wave manipulation, but also has the advantages of low loss, thin thickness and easy integration, thus attracting the attention of researchers all over the world. Terahertz metasurface devices show great potential in planar meta-lenses, vortex beams, digital coded metasurface and holographic imaging, etc. In this review, the phase control principle of the metasurface is analyzed, the characteristics and applications of several kinds of important metasurface devices are summarized, and the challenges in the future and the direction of further development of the metasurface are prospected.

Keywords

• terahertz
• metasurface
• metamaterial
• phase control