A design of electric split-ring metamaterial (eSRM) with tunable terahertz (THz) free spectra range (FSR) characteristic is presented. The proposed eSRM is composed of double semicircle-shaped ring resonators with two connected metallic bars. By changing the radius of the semicircle-shaped ring resonators, the tuning ranges of FSR are 0.187 THz and 0.024 THz in transverse electric (TE) and transverse magnetic (TM) modes, respectively, which indicates eSRM could operate stably in TE and TM modes. Furthermore, eSRM exhibits switching and polarization-dependent characteristics by exploiting comb driver to control the distances between ring resonators along x -and y-axis directions. The electromagnetic responses could be tuned and switched between dual- and quad-resonance in both TE and TM modes. eSRM shows polarization angle-sensitive characteristic and the corresponding FSR could be tuned from 919 GHz to 336 GHz by changing the polarization angle of incident THz wave. In view of the above optical characteristics of eSRM, it is used for the sensing application exposed on different surrounding refraction index. The sensitivity, quality factor (Q-factor), and figure of merit (FOM) are calculated. The sensitivity is 0.457 THz/RIU and the average Q-factor and FOM are 40.65 and 35.47, respectively. These results indicate the proposed eSRM could be used in widespread applications, such as dual-/quad-resonance switches, polarization switches, and high-efficient environmental sensors. [2021-0006].

中文翻译：

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使用电开环超材料的可调谐太赫兹自由光谱范围


提出了一种具有可调谐太赫兹（THz）自由光谱范围（FSR）特性的电开环超材料（eSRM）的设计。所提出的 eSRM 由双半圆形环形谐振器和两个连接的金属棒组成。通过改变半圆形环形谐振腔的半径，横向电（TE）和横向磁（TM）模式下FSR的调谐范围分别为0.187 THz和0.024 THz，这表明eSRM可以在TE和TM模式下稳定工作。此外，eSRM 通过利用梳状驱动器来控制环形谐振器之间沿 x 轴和 y 轴方向的距离，从而表现出开关和偏振相关特性。电磁响应可以在 TE 和 TM 模式下在双谐振和四谐振之间调谐和切换。 eSRM表现出偏振角敏感特性，通过改变入射太赫兹波的偏振角，可以将相应的FSR从919 GHz调谐到336 GHz。鉴于eSRM的上述光学特性，将其用于暴露在不同周围折射率下的传感应用。计算灵敏度、品质因数 (Q-factor) 和品质因数 (FOM)。灵敏度为 0.457 THz/RIU，平均 Q 因子和 FOM 分别为 40.65 和 35.47。这些结果表明所提出的 eSRM 可用于广泛的应用，例如双/四谐振开关、偏振开关和高效环境传感器。 [2021-0006]。