金纳米球壳表面等离激元共振波长调谐特性研究

摘要

The effects of shell thickness, inner core size, and dielectric constants of core and embedding medium on the localized surface plasmon resonance wavelength of gold nanoshell are investigated by Mie theory. The results show that the extinction peak of gold nanoshell is first blue-shifted and then red-shifted with the increase of shell thickness, that the shift shell thickness corresponding to quadrupolar wavelength is greater than that corresponding to dipolar wavelength, and that the ratio of the shift shell thickness to the inner core size decreases with the increase of inner core size, and increases with the increase of dielectric constant of inner core or embedding medium. The resonance peaks in the scattering spectra have similar phenomena to those in extinction spectra as the shell thickness increases. The shift of the spectral peak is ascribed to the plasmon hybridization and phase retardation effect.%　　理论研究了金纳米球壳的几何结构参数，及物理参量对局域表面等离激元共振波长调谐特性的影响。结果表明，随着壳层厚度的增大，球壳消光共振峰先蓝移后红移，高阶峰转向时对应的壳层厚度比低阶峰大，且该厚度与球壳内径的比值随内径尺寸的增大而减小，随内核材料或外界环境介电常数的增大而增大，散射共振峰也有类似的移动规律。利用电子杂化效应和相位延迟效应对该现象进行了理论解释。