We proposed and fabricated J-shaped planar structure metasurfaces to achieve excitation of dual-frequency toroidal dipole resonances simultaneously, which results in electromagnetically induced transparency effect in the terahertz band. The mutual coupling of two asymmetric J-shaped metal rings in the metasurface units excites low-frequency and high-frequency toroidal dipole resonances, and a transparent window was formed. The fitted curves based on the Fano resonance model have a good consistency with the simulated transmission spectrum of the metasurfaces, which explains this coupling effect deeply. The resonant mode and radiant mechanism were revealed by the analysis of the electromagnetic field distribution and the numerical calculation of the multipole moment. Furthermore, the toroidal dipole resonant response can be adjusted by the structural parameter, indicating the sensing characteristics of the metasurfaces. The simple and flexible planar toroidal dipole metasurfaces with electromagnetically induced transparency effect provide more possibilities for the development and application of terahertz functional devices.

我们提出并制造了J形平面结构超表面，以同时实现双频环形偶极子共振的激发，从而在太赫兹频带中产生电磁感应的透明效应。超表面单元中两个不对称的J形金属环的相互耦合激发了低频和高频环形偶极子共振，并形成了一个透明窗口。基于Fano共振模型的拟合曲线与超表面的模拟透射光谱具有良好的一致性，这深刻地解释了这种耦合效应。通过对电磁场分布的分析和多极矩的数值计算，揭示了共振模式和辐射机理。此外，环形偶极子的共振响应可以通过结构参数来调节，表明超表面的传感特性。具有电磁感应的透明效应的简单而灵活的平面环形偶极子超表面为太赫兹功能器件的开发和应用提供了更多的可能性。