Wang Huimin, Wang Tao, Yan Ruoqin, Yue Xinzhao, Wang Lu, Wang Yuandong, Zhang Jinyan, Wang Jian
Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Nanotechnology. 2022 Aug 30;33(46). doi: 10.1088/1361-6528/ac86dd.
A sensor based on plasmon-waveguide resonance (PWR) exhibits an impressive narrow linewidth and has attracted extensive attention in plasmon label-free sensing. However, the low surface electric field intensity limits the detection ability of biomolecules, where the refractive index changes are restricted at the sensor surface. In this study, we study the coupling of PWR and multiple plasma modes in a hyperbolic metamaterial (HMM), combining narrow linewidth and electric field enhancement advantages. The PWR-HMM sensor includes a gold film, lossless dielectric layer, and metal/dielectric multilayer HMM array composed of 2-layer Au/AlOstacks. The evanescent field of PWR is used to excite multiple plasma modes in the HMM. The figure of merit of the proposed structure reaches 5417/RIU owing to the existence of lossless dielectric layer, which is 11.7 times than the conventional gold film structure. The maximum bulk sensitivity of the PWR-HMM sensor was 43 000 nm/RIU. In comparison with PWR, the surface electric field intensity and the surface sensitivity of PWR-HMM increase by four and two times, respectively. Furthermore, comparing the sensing performance of the PWR-HMM sensor and PWR-nanoparticle (NP) sensor (coupling PWR and localized surface plasmon resonance), it was found that PWR-HMM has 20% higher surface sensitivity than the PWR-NP. A sensing mechanism coupling PWR and multiple plasma modes in the HMMs opens a gate to significantly improve the PWR sensors performance, which is expected to be used to resolve urgent issues in biological, medical and clinical applications.
基于表面等离子体波导共振（PWR）的传感器具有令人印象深刻的窄线宽，在表面等离子体无标记传感方面引起了广泛关注。然而，低表面电场强度限制了生物分子的检测能力，其中折射率变化被限制在传感器表面。在本研究中，我们研究了双曲线型超材料（HMM）中PWR与多种等离子体模式的耦合，结合了窄线宽和电场增强的优点。PWR-HMM传感器包括金膜、无损介电层以及由2层Au/AlO堆栈组成的金属/介电多层HMM阵列。PWR的倏逝场用于激发HMM中的多种等离子体模式。由于无损介电层的存在，所提出结构的品质因数达到5417/RIU，是传统金膜结构的11.7倍。PWR-HMM传感器的最大体灵敏度为43000nm/RIU。与PWR相比，PWR-HMM的表面电场强度和表面灵敏度分别提高了四倍和两倍。此外，比较PWR-HMM传感器和PWR-纳米颗粒（NP）传感器（耦合PWR和局域表面等离子体共振）的传感性能，发现PWR-HMM的表面灵敏度比PWR-NP高20%。一种在HMM中耦合PWR和多种等离子体模式的传感机制为显著提高PWR传感器性能打开了一扇大门，有望用于解决生物、医学和临床应用中的紧迫问题。
