Xu Shi-Tong, Sun Tong, Li Jian-Di, Lv Yang, Wang Ying-Hua, Pan Yue, Cao Hong-Zhong, Ma Ren-De, Fan Fei
Appl Opt. 2025 Jun 20;64(18):5054-5059. doi: 10.1364/AO.559315.
Dynamic tuning of terahertz (THz) electromagnetically induced transparency (EIT) is of great significance for THz applications in slow light, switching, and sensing. In this study, we present a THz EIT metasurface that utilizes a combination of circular and U-shaped ring resonators (CRR and USRR) based on bright-quasi-dark mode coupling. Different from the conventional methods that only focus on the modulation of the EIT transparent window, this work achieves active control with both the EIT window and the nearby resonance after integration with graphene, which extends more THz modulation channels. The simulation results show that the hybrid metasurface has a modulation depth of 81.4% at the EIT window, and the resonance adjacent to the EIT peak achieves a remarkable modulation depth of 97.5%. In addition, the proposed EIT metasurface is capable of refractive index sensing with high sensitivity. This study not only elucidates the universal interaction between graphene and metallic metasurfaces but also paves the way for the development of compact and active THz slow light and sensor devices.
太赫兹（THz）电磁诱导透明（EIT）的动态调谐对于THz在慢光、开关和传感方面的应用具有重要意义。在本研究中，我们展示了一种基于亮准暗模式耦合，利用圆形和U形环谐振器（CRR和USRR）组合的太赫兹EIT超表面。与仅专注于EIT透明窗口调制的传统方法不同，这项工作在与石墨烯集成后，实现了对EIT窗口和附近共振的主动控制，扩展了更多的太赫兹调制通道。仿真结果表明，混合超表面在EIT窗口处的调制深度为81.4%，与EIT峰值相邻的共振实现了高达97.5%的显著调制深度。此外，所提出的EIT超表面能够进行高灵敏度的折射率传感。本研究不仅阐明了石墨烯与金属超表面之间的普遍相互作用，也为紧凑型有源太赫兹慢光和传感器器件的发展铺平了道路。
