We propose a dual-band terahertz metamaterial sensor (MS), which exhibits the low loss and high quality (Q) factor of electromagnetically induced transparency (EIT) effects at the frequencies of 0.89 THz and 1.56 THz simultaneously. The physical natures of EIT effects are analyzed by using numerical simulations and a “two particle” model. Further, THz sensing is performed based on the shifts of two EIT resonances when the analyte is coated at the metamaterial surface. The sensitivities of the sensor are investigated with respect to different thicknesses, cover areas and refractive indexes of the coated analyte film. Results show that the first EIT resonance is suitable for sensing the analyte with the refractive index from 1.5 to 2, while the second EIT resonance is more suitable for sensing the refractive index of the analyte from 1 to 1.5. The sensitivity is 280.8 GHz/RIU, the average Q value is 14.3, and the figure of merit (FOM) value is 4 for the first EIT resonance. Meanwhile, the sensitivity is 201.6 GHz/RIU, the average Q value is 56.9, and the FOM value is 11.5 for the second EIT resonance. Such a metamaterial sensor with high refractive index sensitivity and dual-band would have great potentials for promoting the developments of multi-band/broadband terahertz sensing and detection technology.

中文翻译：

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双波段电磁感应透明 (EIT) 太赫兹超材料传感器

我们提出了一种双波段太赫兹超材料传感器 (MS)，它同时在 0.89 THz 和 1.56 THz 的频率下表现出电磁感应透明 (EIT) 效应的低损耗和高质量 (Q) 因子。通过使用数值模拟和“双粒子”模型来分析 EIT 效应的物理性质。此外，当分析物涂覆在超材料表面时，基于两个 EIT 共振的位移来执行太赫兹传感。针对不同厚度、覆盖面积和涂层分析物膜的折射率来研究传感器的灵敏度。结果表明，第一次EIT共振适合检测折射率为1.5~2的分析物，而第二次EIT共振更适合检测折射率为1~1.5的分析物。灵敏度为 280.8 GHz/RIU，平均 Q 值为 14.3，第一次 EIT 谐振的品质因数 (FOM) 值为 4。同时，灵敏度为201.6 GHz/RIU，平均Q值为56.9，第二次EIT谐振的FOM值为11.5。这种具有高折射率灵敏度和双波段的超材料传感器对于推动多波段/宽带太赫兹传感和检测技术的发展具有巨大潜力。