Abstract Chiral metasurfaces can achieve giant chiral optical responses and have been expanded from the optical band to other electromagnetic bands. Here, we propose a new method for dynamic terahertz circular dichroism (CD) manipulation in metasurfaces. By introducing a patterned and electrically doped graphene into the metamirror consists of double layer C-shaped split ring resonators (SRRs), efficient terahertz CD modulation is observed. Since the electrical doping of graphene changes the absorption loss of the metasuface cavity, the structure shows switching between a chiral metasurface and an ordinary metal mirror, which can be seen as "on" and "off" states. The calculation results show an efficient modulation of the terahertz CD in a large dynamic range. In addition, we also use the new method to design two metasurfaces for dynamic terahertz wavefront modulation and near-field digital imaging, both of which show a high-performance electrical switching. This method provides a new way for the design of active terahertz devices based on metasurfaces, and also promotes the applications of terahertz chiral metasurfaces in high-speed wireless communication and dynamic imaging.

中文翻译：

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用于动态太赫兹波前调制和近场成像的金属-石墨烯混合活性手性超表面

摘要 手性超表面可以实现巨大的手性光学响应，并已从光学波段扩展到其他电磁波段。在这里，我们提出了一种在超表面中动态太赫兹圆二色性 (CD) 操作的新方法。通过将图案化和电掺杂的石墨烯引入由双层 C 形裂环谐振器 (SRR) 组成的超镜面，观察到有效的太赫兹 CD 调制。由于石墨烯的电掺杂改变了超表面腔的吸收损耗，该结构表现出手性超表面和普通金属镜之间的切换，可以看作是“开”和“关”状态。计算结果显示了在大动态范围内对太赫兹 CD 的有效调制。此外，我们还使用新方法设计了两个用于动态太赫兹波前调制和近场数字成像的超表面，两者都显示出高性能的电开关。该方法为基于超表面的有源太赫兹器件设计提供了新途径，也促进了太赫兹手征超表面在高速无线通信和动态成像中的应用。