School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan 523808, China.
College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, China.
Sensors (Basel). 2024 Jun 4;24(11):3649. doi: 10.3390/s24113649.
Quasi-bound state in the continuum (QBIC) can effectively enhance the interaction of terahertz (THz) wave with matter due to the tunable high-Q property, which has a strong potential application in the detection of low-concentration biological samples in the THz band. In this paper, a novel THz metamaterial sensor with a double-chain-separated resonant cavity structure based on QBIC is designed and fabricated. The process of excitation of the QBIC mode is verified and the structural parameters are optimized after considering the ohmic loss by simulations. The simulated refractive index sensitivity of the sensor is up to 544 GHz/RIU, much higher than those of recently reported THz metamaterial sensors. The sensitivity of the proposed metamaterial sensor is confirmed in an experiment by detecting low-concentration lithium citrate (LC) and bovine serum albumin (BSA) solutions. The limits of detection (LoDs) are obtained to be 0.0025 mg/mL (12 μM) for LC and 0.03125 mg/mL (0.47 μM) for BSA, respectively, both of which excel over most of the reported results in previous studies. These results indicate that the proposed THz metamaterial sensor has excellent sensing performances and can well be applied to the detection of low-concentration biological samples.
无界局域态（Quasi-bound state in the continuum，QBIC）由于可调谐的高品质因数（high-Q）特性，可以有效地增强太赫兹（terahertz，THz）波与物质的相互作用，在 THz 波段中对低浓度生物样品的检测具有很强的潜在应用价值。本文设计并制作了一种基于 QBIC 的具有双链分离谐振腔结构的新型太赫兹超材料传感器。通过模拟考虑欧姆损耗，验证了 QBIC 模式的激发过程，并对结构参数进行了优化。该传感器的模拟折射率灵敏度高达 544 GHz/RIU，远高于最近报道的太赫兹超材料传感器。通过检测低浓度的柠檬酸钠（lithium citrate，LC）和牛血清白蛋白（bovine serum albumin，BSA）溶液，实验证实了所提出的超材料传感器的灵敏度。分别得到 LC 的检测限（limit of detection，LoD）为 0.0025 mg/mL（12 μM），BSA 的 LoD 为 0.03125 mg/mL（0.47 μM），均优于之前研究中大多数报道的结果。这些结果表明，所提出的太赫兹超材料传感器具有优异的传感性能，可很好地应用于低浓度生物样品的检测。
