Using numerical calculations, we present the design of terahertz transmission modulators based on transmissive metal–insulator–metal metasurfaces, which consist of two planar arrays of parallel metallic ribbons while the deeply-subwavelength space between them is infiltrated with nematic liquid crystals (LCs). We demonstrate that only metasurfaces with narrow lateral gaps between adjacent metallic ribbons have a single transmission peak and low background transmission. Spectral shifting of the transmission peak is then provided by the electrical control of the LC refractive index. The proposed modulators operate either as spectrally-tunable passband filters in a certain frequency range or as amplitude (transmission) modulators at a single specified frequency. Optimal modulators have the following properties: maximal relative spectral shift of around 10%, transmittance change of around 0.6, modulation depth of around 90%, insertion loss of 40%, and switching time of around . The modulators have a very simple geometry, which provides a straightforward design procedure and selection of geometrical parameters for specified operating frequency.

中文翻译：

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使用渗透有液晶的金属-绝缘体-金属超表面的电可调太赫兹传输调制器

通过数值计算，我们提出了基于透射金属-绝缘体-金属超表面的太赫兹传输调制器的设计，该调制器由两个平行金属带平面阵列组成，而它们之间的深亚波长空间则渗透有向列液晶（LC）。我们证明，只有相邻金属带之间具有窄横向间隙的超表面才具有单一透射峰和低背景透射率。然后通过 LC 折射率的电控制来提供传输峰的光谱偏移。所提出的调制器既可以作为特定频率范围内的频谱可调谐通带滤波器，也可以作为单个指定频率的幅度（传输）调制器。最佳调制器具有以下特性：最大相对光谱偏移约为 10%、透射率变化约为 0.6、调制深度约为 90%、插入损耗约为 40%、开关时间约为 。调制器具有非常简单的几何结构，可提供简单的设计程序以及针对指定工作频率的几何参数选择。