Nowadays, the simplicity of both designing and fabrication process of a terahertz (THz) resonator-based sensing technique leads to its ongoing development. The consumable THz resonator needs to be easily integrated into an existing terahertz time domain spectroscopy (THz TDS) measurement system. It should also be able to be fabricated in a mass scale with a low production cost. In this work, a metal-coated surface plasmon resonance- (SPR-) based sensor is simulated and designed as a low-cost refractive index sensor utilizing rigorous coupled wave analysis (RCWA). To demonstrate our methodology, we design a gold-coated grating with a polydimethylsiloxane (PDMS) as a substrate, in order to perform quantitative analysis of gasoline-toluene mixture composition, which has a refraction index variation of 0.1 at THz frequency. The grating period is tuned such that its surface plasmon resonance (SPR) frequency matches with the peak frequency of the THz TDS system. Moreover, other grating parameters, i.e., a filling factor and a grating depth, are optimized to increase the sensor sensitivity and sharpen the resonance dip. High sensitivity up to 500 GHz/RIU with a refractive index resolution up to 0.01 is numerically revealed. The H-field of the designed grating is then evaluated to indicate a strong SPR excitation. The well-developed designed grating introduces a promising, low-cost, and easily fabricated THz refractive index sensor.

中文翻译：

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表面等离子共振金属光栅在折射率传感器应用中最大化THz灵敏度的仿真

如今，基于太赫兹（THz）谐振器的传感技术的设计和制造工艺的简便性导致其不断发展。易耗THz谐振器需要轻松集成到现有的太赫兹时域光谱（THz TDS）测量系统中。它还应该能够以较低的生产成本大规模制造。在这项工作中，基于金属涂层的表面等离振子共振（SPR-）的传感器被仿真并设计为利用严格耦合波分析（RCWA）的低成本折射率传感器。为了演示我们的方法，我们设计了一个以聚二甲基硅氧烷（PDMS）为基底的镀金光栅，以便对汽油-甲苯混合物的成分进行定量分析，该混合物在THz频率下的折射率变化为0.1。调整光栅周期，使其表面等离子体共振（SPR）频率与THz TDS系统的峰值频率匹配。此外，优化其他光栅参数，即填充系数和光栅深度，以增加传感器灵敏度并锐化谐振谷。从数值上揭示了高达500 GHz / RIU的高灵敏度和高达0.01的折射率分辨率。然后评估设计光栅的H场以指示强烈的SPR激发。精心设计的光栅引入了一种有前途的，低成本的，易于制造的太赫兹折射率传感器。进行了优化，以提高传感器灵敏度并锐化谐振谷。从数值上揭示了高达500 GHz / RIU的高灵敏度和高达0.01的折射率分辨率。然后评估设计光栅的H场以指示强烈的SPR激发。精心设计的光栅引入了一种有前途的，低成本的，易于制造的太赫兹折射率传感器。进行了优化，以提高传感器灵敏度并锐化谐振谷。从数值上揭示了高达500 GHz / RIU的高灵敏度和高达0.01的折射率分辨率。然后评估设计光栅的H场以指示强烈的SPR激发。精心设计的光栅引入了一种有前途的，低成本的，易于制造的太赫兹折射率传感器。