嵌入式纳米金阵列的表面等离子共振传感特性研究

Sensing characteristics of surface plasmon resonance based on embedded gold nanoparticle array

基于本征值方程及时域有限差分(FDTD)算法,研究了嵌入二氧化硅衬底的菱形纳米金阵列表面等离子共振传感特性,推导出共振模式随嵌入深度变化的关系式。计算结果与数值模拟一致,验证了金纳米颗粒阵列上下介质的不对称性可以等效为单层介质光栅。理论分析了透射谱中产生多个共振峰的物理机制与影响因素,进一步探讨了透射谱与嵌入深度、长短轴比例、周期尺寸等参数的关系,分析了阵列结构的传感性能特点,为制作多波段工作的表面等离子体共振(SPR)传感器基底提供了理论依据。

Based on the eigenvalue equation and finite-difference time-domain （FDTD） algorithm, the surface plasmon resonance sensing characteristics of rhombic gold nanoparticle arrays embedded in silica substrate are investigated, and relationship between the resonance mode and embedded depth is derived. The calculated results agree with the numerical simulation, which shows that the asymmetry of the upper and lower media of gold nanoparticle arrays can be equivalent to monolayer dielectric grating. The physical mechanism and int^uence factors of generating multiple resonance peaks in the transmission spectra axe analyzed theoretically. Relationships between the transmission spectrum and embedded depth, axial ratio, array period are further discussed. The sensing performance of array structure is analyzed. It provides a theoretical basis for the fabrication of multi-band surface plasmon resonance（SPR） sensor substrate.