Terahertz (THz) science and technology have received increasing demand in recent decades for sensing applications. Additionally, THz metamaterials have presented unique characteristics for sensing applications owing to their adjustable resonance frequency. In this paper, we propose a polarization independent metasurface structure serving as a refractive-index-based sensor at THz frequencies. The unit cell is composed of two perpendicularly intersecting metallic bars at the middle of which a cylindrical metallic element is placed. The structure represents a sharp resonance with a high Q-factor of 475 in the absorption profile, which, in some cases, can even reach values as high as 3052.75, revealing confinement of the profile in a narrow band around the resonance frequency of 1.75 THz. Furthermore, the highest values of sensitivity and the figure of merit turn out to be, respectively, 7000 nm/RIU and 19.44 1/RIU, both of which can even take higher values of 11500 nm/RIU and 89.15 1/RIU, respectively, in some special cases of structural dimensions. Finally, the sensor is successfully employed for detecting crystalline sugar molecules.

中文翻译：

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用于卓越折射率传感的高 Q 因子太赫兹超材料

近几十年来，太赫兹 (THz) 科学和技术对传感应用的需求不断增加。此外，太赫兹超材料由于其谐振频率可调，在传感应用中呈现出独特的特性。在本文中，我们提出了一种偏振无关的超表面结构，用作太赫兹频率下基于折射率的传感器。单元电池由两个垂直相交的金属棒组成，中间放置一个圆柱形金属元件。该结构在吸收曲线中表现出具有 475 高 Q 因子的尖锐共振，在某些情况下，甚至可以达到高达 3052.75 的值，这表明该曲线被限制在 1.75 THz 共振频率附近的窄带中. 此外，灵敏度和品质因数的最高值分别为 7000 nm/RIU 和 19.44 1/RIU，在某些情况下，两者甚至可以分别采用更高的值 11500 nm/RIU 和 89.15 1/RIU结构尺寸的特殊情况。最后，该传感器成功用于检测结晶糖分子。