聚集效应对银纳米粒子的二阶非线性光学特性的影响研究

Study on the influence on the characteristic of the second-order nonlinear optics by using aggregation of silver nanoparticles

运用超瑞利散射 (HRS)技术 ,对由KNO3诱导聚集的银纳米粒子的二阶光学非线性特性进行了实验研究 .通过粒子尺寸测量和透射电镜观察 ,表明银纳米粒子的聚集方式为链状聚集 .当聚集体平均尺寸为 12 0nm时 ,银纳米粒子聚集体的HRS信号强度比聚集前增大了约 15倍 .分析表明 ,聚集导致银纳米粒子表面电场极化强度的增强和极化分布的改变 。

The hyper-Rayleigh scattering( HRS) technique has been employed to determine the second-order nonlinear optical response of a highly monodisperse silver colloid and its aggregation which is induced in the presence of KNO3. Through the size distribution and TEM measurements, the silver nanoparticle aggregates have been observed as a chain-like aggregation. The experimental result reveals that HRS signal increases 15 times when the aggregation average size is up to 120nm.