Guo Shijing, Li Chao, Wang Dong, Chen Wenya, Gao Song, Wu Guozheng, Xiong Jiaran
Appl Opt. 2024 Mar 10;63(8):1962-1970. doi: 10.1364/AO.509461.
In this paper, a dual-band terahertz metamaterial sensor based on aluminum and silicon is proposed and simulated. The aluminum surface, which is deposited on a silicon substrate, is made of a C-shaped frame resonator, a rectangular beam, and a cross. The device is insensitive to the change of incident angle in the range of 0°-30°, which shows the great transmission stability of the sensor. By examining the resonance frequency shift, it is shown that 98.3 and 237.5 GHz/RIU refractive index sensitivity can be obtained near 1.76 and 2.404 THz transmission dips of the proposed structure, respectively. The two dips can be used to sense analytes in different refractive index ranges, respectively. For Dip 1 at 1.76 THz, the range is 1.0-1.6. For Dip 2 at 2.404 THz, the range is 1.6-2.0. Different from traditional multi-band metamaterial sensors, two dips generated by the proposed device can measure continuous and non-multiplexed refractive index ranges, respectively. Because the resonance frequencies of matters are different, such a characteristic enables the device to measure different types of analyte using the appropriate resonant peak. A central-relief design is then proposed based on perturbation theory to further improve its sensing performance. The aluminum cross is covered by polyimide, which can interfere with the scattering field on the metal surface and affect the transmission results. For both transmission dips, the optimized structure realizes higher sensitivities of 111.7 GHz/RIU and 262.5 GHz/RIU, respectively. More significantly, the optimized structure also has the characteristic of a wide and non-multiplexed refractive index range. In addition, the effects of analyte thickness and polyimide layer thickness on sensor performance are also discussed. The proposed structure opens up new prospects in the design of multiple-band terahertz metamaterial sensors. It can also meet the sensing needs of biomedical, environmental monitoring, and industrial manufacturing.
本文提出并模拟了一种基于铝和硅的双波段太赫兹超材料传感器。沉积在硅衬底上的铝表面由C形框架谐振器、矩形梁和十字形组成。该器件在0°-30°范围内对入射角的变化不敏感，这表明了传感器具有良好的传输稳定性。通过研究共振频率偏移，结果表明在所提出结构的1.76和2.404太赫兹传输凹陷附近，分别可获得98.3和237.5千兆赫/折射率单位（GHz/RIU）的折射率灵敏度。这两个凹陷可分别用于检测不同折射率范围内的分析物。对于1.76太赫兹处的凹陷1，范围是1.0-1.6。对于2.404太赫兹处的凹陷2，范围是1.6-2.0。与传统的多波段超材料传感器不同，所提出的器件产生的两个凹陷可分别测量连续且非复用的折射率范围。由于物质的共振频率不同，这种特性使该器件能够使用适当的共振峰来测量不同类型的分析物。然后基于微扰理论提出了一种中心浮雕设计，以进一步提高其传感性能。铝十字形被聚酰亚胺覆盖，这会干扰金属表面的散射场并影响传输结果。对于两个传输凹陷，优化后的结构分别实现了更高的灵敏度，即111.7 GHz/RIU和262.5 GHz/RIU。更重要的是，优化后的结构还具有宽且非复用的折射率范围的特性。此外，还讨论了分析物厚度和聚酰亚胺层厚度对传感器性能的影响。所提出的结构为多波段太赫兹超材料传感器的设计开辟了新的前景。它还可以满足生物医学、环境监测和工业制造的传感需求。
