金纳米球壳对的局域表面等离激元共振特性分析

应用有限元方法, 研究金纳米球壳对的几何结构参数及物理参量对其表面等离激元共振的散射及消光光谱的影响, 并根据等离激元杂化理论进行了理论分析. 结果表明, 随着金壳厚度的增加, 金纳米球壳对的散射及消光共振峰先发生蓝移而后红移, 而随着金纳米球壳间隙的减小, 或者随着金纳米球壳的内核尺寸或内核介质折射率的增大, 散射及消光共振峰均发生红移; 随着金壳厚度或内核尺寸减小, 或者随着内核介质折射率增大, 金纳米球壳对的散射与消光共振强度减弱, 而随着金壳间隙的减小, 金纳米球壳对的散射共振强度先增强后减弱, 而消光共振强度逐渐增强, 数值模拟与理论分析一致.

Properties of localized surface plasmon resonance of gold nanoshell pairs

The characteristics of scatting and extinction spectra of gold nanoshell pairs, dependent on the its geometry and physical parameters, are investigated by the Finite Element Method based on the plasmon hybridization theory. The numerical results indicate that the resonante peaks in the scattering spectra and the extinction spectra emerge from blue-shift to red-shift with the increases of the thickness of gold nanoshells, whereas they present the red-shift with the decrease of the interparticle separation or with the increases of the size and the refractive index of inner core of gold nanoshells. In the same time, for the case of decreasing the inner core size and the shell thickness or increasing the refractive index of inner core, the intensity of the scattering resonance and the extinction resonance decrease. And, with the decrease of the interparticle separation, the intensity of the scattering resonance of gold nanoshell pairs trends to first increase and then decrease, while the intensity of the extinction resonance increases gradually. All the above is in agreement with the analysis of the plasmon hybridization theory.