基于局域表面等离激元的传感器物理机理和应用研究

表面等离激元微纳结构在超分辨成像、传感和检测上有重要的应用。其中基于局域表面等离激元折射率传感的医学检测系统被认为是下一代便携式医学检测系统的发展方向，基于表面增强的拉曼散射被认为是可以检测任何物质的存在。但是这两个方向均存在急需克服的问题，比如低局域表面等离激元折射率传感器的品质因子，疾病标志物的检测技术有待发展，表面等离激元增强的拉曼散射衬底的均匀性和测量的可重复性低。本项目通过新型光场调控去解决这些问题，提出设计超高品质因子局域等离激元折射率传感器新方法，实验上实现品质因子超过600。演示基于局域表面等离激元折射率传感器的医学检测系统，并将甲胎蛋白的检测灵敏度提高到0.4 ng/ml。提出设计具有高“热点”强度和密度的表面增强拉曼散射衬底新方法，制备相应的具有高增强因子、均一性和可重复性的拉曼散射衬底，应用到检测有毒有害物质的浓度上。推动表面等离激元在医学、环境和食品检测中的应用。

Plasmonic micro-/nano-structures have important applications in super-resolution imaging, sensing and medical diagnosing. The medical diagnosing system based on the localized surface polariton refractive index sensor is thought to be a next generation of the portable medical diagnosing system, surface enhanced Raman scattering (SERS) can detect any content of materials even single molecular. However, there still exist some challenges in these two fields, for example, the low Figure of Merit (FOM) of localized surface plasmon polariton refractive index sensors, the detection technology for the disease markers, and the inhomogeneity and low repeatability of the signal of surface enhanced Raman scattering. This project is aimed to solve these challenges through tuning the light fields. This project will propose novel methods to design the refractive index sensors based localized surface plasmon polaritons with ultrahigh figure of merit (over 600), and experimentally demonstrate these sensors. We will demonstrate the medical detecting system based on localized surface plasmon polariton refractive index sensors, and the detection limit of the alpha fetoprotein will be better than 0.4 ng/ml. We will propose novel physical mechanism to design SERS substrates with high enhanced factor and ultrahigh density of "hot spots". We will develop nanotechnology to fabricate such SERS substrates with high enhanced factor, uniformity and repeatability, which will be used in the detection of the concentration of poisonous and harmful materials. The project will push forward the application of surface plasmon polaritons in medical diagnosing, environment monitoring and food safety.