基于远场光谱的表面等离激元耦合特性研究

Properties of Surface Plasmon Coupling Based on Far-Field Spectroscopy

采用快速热退火方法制备了尺寸较小、密度较高的银纳米颗粒阵列,其面密度在一定区间可调控。通过实验测得银纳米颗粒阵列的远场反射和透射谱,进一步经理论数值变换,研究了所制备银纳米颗粒阵列的吸收、散射及消光特性。从谱线的变化趋势可知,当银纳米颗粒阵列的面密度不断增大、即颗粒间距逐步减小时,所产生的局域表面等离激元共振的波长发生红移;而且相邻金属纳米颗粒的耦合作用越强,波长红移越明显。该方法为分析高密度、小尺寸,特别是粒子间存在耦合的金属纳米颗粒阵列的等离激元特性提供了有效参考。

In this work,we fabricate silver nanoparticle arrays with a small size,high density,and controllable surface densities in a specific range using a rapid thermal annealing method.Based on the far-field optical reflection and transmission spectra of the silver nanoparticle arrays that are experimentally measured and according to a theoretical numerical conversion,the absorption,scattering,and extinction properties of the silver nanoparticle arrays are investigated.The results show that the resonance wavelength derived from the localized surface plasmon tends to redshift with an increase in surface density of the silver nanoparticle arrays(i.e.,decreased nanoparticle spacing).In addition,the redshift is more pronounced for stronger coupling interactions between neighboring nanoparticles.This method provides a helpful reference for analyzing localized surface plasmon properties,primarily for small high-density metal nanoparticle arrays with non-negligible inter-particle coupling interactions.