用于生物传感的相位调制的铝膜-石墨烯结构

为了提高铝基等离子体传感器的灵敏度和稳定性,提出了一种基于相位调制增敏的表面等离子体共振传感结构:铝膜-石墨烯复合结构.采用Kretschmann传感结构,将铝膜和多层石墨烯依次沉积在高折射率棱镜上.基于传输矩阵原理,模拟计算激发光波长为632.8 nm时,几何结构参数对传感性能的变化规律.研究结果表明,相比于传统的角度调制模式,该传感结构采用相位调制模式,可以实现2个数量级的灵敏度增强.同时,石墨烯薄层的引入不仅能够有效阻止等离子体铝膜被氧化,而且能够产生近83倍的探测灵敏度增强因子.对于界面折射率变化为1.333~1.334 2 RIU,该复合结构的最大差分相位为94.663o,能够产生超高的相位探测灵敏度7.888 5×10^4 o/RIU.该传感结构可为开发低成本、超灵敏的铝基等离子体传感器件提供参考.

Aluminum-graphene Structure Based on Phase Modulation Employed for Biosensing

In order to further improve the sensitivity and stability of aluminum-based plasmonic sensor,a plasmonic configuration named aluminum-graphene hybrid structure, was proposed based on phase modulation. Employing a high refractive index prism, the plasmonic configuration excited by the Kretschamnn mode,was designed by depositing graphene layers onto aluminum film. With the help of the transmission matrix theory,the variation of geometry parameters on sensing performance was studied when the excitation wavelength With the help of the transmission matrix theory,the variation of geometry parameters on sensing performance was studied when the excitation wavelength was set to 632.8 nm. The calculated results show that, the proposed aluminum-graphene hybrid structure designed by phase modulation have provided 2 orders of magnitude higher sensitivity compared with conventional surface plasmon resonance sensors designed by angular modulation. Moreover,the introduction of graphene can not only efficiently hinder the oxidation of plasmonic aluminum film,but also enhance the detection sensitivity as high as 83 times. For a tiny refractive index variation of 1.333~1.334 2 in sensing interface,the proposed configuration can provide a higher phase change of 94.663 oand a phase detection sensitivity as high as 7.888 5×10^4 o/RIU. The proposed surface plasmon resonance configuration can provide a reference for designing low-cost and ultrasensitive plasmonic sensors.