School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, China.
Biosensors (Basel). 2023 Jun 15;13(6):654. doi: 10.3390/bios13060654.
Surface plasmon resonance sensors have been widely used in various fields for label-free and real-time detection of biochemical species due to their high sensitivity to the refractive index change of the surrounding environment. The common practices to achieve the improvement of sensitivity are to adjust the size and morphology of the sensor structure. This strategy is tedious and, to some extent, limits the applications of surface plasmon resonance sensors. Instead, the effect of the incident angle of excited light on the sensitivity of a hexagonal Au nanohole array sensor with a period of 630 nm and a hole diameter of 320 nm is theoretically investigated in this work. By exploring the peak shift of reflectance spectra of the sensor when facing a refractive index change in (1) the bulk environment and (2) the surface environment adjacent to the sensor, we can obtain the bulk sensitivity and surface sensitivity. The results show that the bulk sensitivity and surface sensitivity of the Au nanohole array sensor can be improved by 80% and 150%, respectively, by simply increasing the incident angle from 0° to 40°. The two sensitivities both remain nearly unchanged when the incident angle further changes from 40° to 50°. This work provides new understanding of the performance improvement and advanced sensing applications of surface plasmon resonance sensors.
表面等离子体共振传感器由于对周围环境折射率变化具有高灵敏度，因此已被广泛应用于各种领域，用于进行无标记和实时的生化物质检测。常见的提高灵敏度的方法是调整传感器结构的尺寸和形态。这种策略繁琐，在某种程度上限制了表面等离子体共振传感器的应用。相反，本工作从理论上研究了激发光入射角对周期为 630nm、孔径为 320nm 的六边形 Au 纳米孔阵列传感器灵敏度的影响。通过探测传感器在（1）体相环境和（2）紧邻传感器的表面环境中面对折射率变化时反射谱的峰值位移，可以得到体相灵敏度和表面灵敏度。结果表明，通过简单地将入射角从 0°增加到 40°，Au 纳米孔阵列传感器的体相灵敏度和表面灵敏度分别提高了 80%和 150%。当入射角进一步从 40°增加到 50°时，这两种灵敏度几乎保持不变。这项工作为表面等离子体共振传感器的性能提升和先进传感应用提供了新的认识。
