It is very meaningful to implement a tunable transparency window device with a simple metasurface structure in the mid-infrared band. In this paper, we propose a symmetric metasurface structure that consists of thin layers of graphene and a split anti-ring (SAR). This structure can achieve a tunable lattice-induced transparency-like (LIT-like) spectral response in the wide frequency range of 20–40 THz. Our simulation results show that the realization of the LIT-like phenomenon is due to the strong coupling between the lattice diffraction resonance mode (LDRM) and the wide plasmon resonance mode produced by SAR. The LIT-like response can be dynamically shifted by adjusting the incident pitch angle, the single and double LIT-like can also be switched by adjusting the azimuth angle, which provides convenient post-fabrication tunability. The coupling mechanism of the single LIT-like phenomenon is explained via a dual-oscillator model, which agrees well with the simulation results. In addition, the effects of spacer layer thickness, spacer layer refractive index, ambient refractive index on the position and size of the transparency window are analyzed. Lastly, a tunable delay bandwidth product between 0.46 and 0.86 will be produced due to the addition of graphene. Our finding manifests a novel design of the mid-infrared dynamically tuned slow-light device.

在中红外波段实现一个具有简单超表面结构的可调透明窗口装置是非常有意义的。在本文中，我们提出了一种由石墨烯薄层和分裂反环（SAR）组成的对称超表面结构。这种结构可以在 20-40 THz 的宽频率范围内实现可调谐的晶格诱导类透明 (LIT-like) 光谱响应。我们的模拟结果表明，类 LIT 现象的实现是由于晶格衍射共振模式 (LDRM) 和 SAR 产生的宽等离子体共振模式之间的强耦合。LIT-like 响应可以通过调整入射俯仰角来动态移动，单双 LIT-like 也可以通过调整方位角来切换，这提供了方便的后期可调性。单个LIT样现象的耦合机制通过双振荡器模型进行解释，与仿真结果吻合良好。此外，分析了间隔层厚度、间隔层折射率、环境折射率对透明窗位置和尺寸的影响。最后，由于添加了石墨烯，将产生介于 0.46 和 0.86 之间的可调延迟带宽积。我们的发现体现了中红外动态调谐慢光设备的新颖设计。由于添加了石墨烯，将产生介于 0.46 和 0.86 之间的可调延迟带宽积。我们的发现体现了中红外动态调谐慢光设备的新颖设计。由于添加了石墨烯，将产生介于 0.46 和 0.86 之间的可调延迟带宽积。我们的发现体现了中红外动态调谐慢光设备的新颖设计。