In the field of optoelectronics, circular dichroism (CD) has caused great research interest because it is widely used in imaging and biosensing. A new method for dynamically controlling terahertz (THz) CD in metamaterials is proposed. By introducing chirality and graphene to metamaterials, a pair of chiral structures with completely opposite responses to left‐handed circularly polarized (LCP) waves and right‐handed circularly polarized (RCP) waves are designed. The influencing factors of CD are explored, including the gap of the structure, the linewidth of graphene, and the Fermi level of graphene. The largest CD (ΔR) is 77%. The CD can be actively modulated in a modulation range of 39–77% and the modulation depth is up to 38%. In addition, two‐channel and four‐channel chiral metasurfaces for near‐field imaging are designed in this way. Good imaging effects and on (“1”) or off (“0”) effects of the multichannel metasurface are demonstrated. This work provides new ideas for the design of tunable metasurfaces and promotes the application of metasurfaces in THz dynamic imaging.

中文翻译：

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可调圆二色性的金属-石墨烯混合手性超材料

在光电子学领域，圆二色性（CD）已引起广泛的研究兴趣，因为它广泛用于成像和生物传感。提出了一种动态控制超材料中太赫兹（THz）CD的新方法。通过将手性和石墨烯引入超材料，设计了一对手性结构，它们对左旋圆极化（LCP）波和右旋圆极化（RCP）波具有完全相反的响应。探讨了CD的影响因素，包括结构的间隙，石墨烯的线宽和石墨烯的费米能级。最大CD（ΔR）是77％。CD可以在39–77％的调制范围内进行主动调制，调制深度最高可达38％。此外，以此方式设计了用于近场成像的两通道和四通道手性超颖表面。演示了良好的成像效果以及多通道超表面的开启（“ 1”）或关闭（“ 0”）效果。这项工作为可调谐超颖表面的设计提供了新思路，并促进了超颖表面在太赫兹动态成像中的应用。