金和银纳米粒子二维周期阵列的光学性质

本文利用离散点偶极子近似方法(DDA)研究了金和银纳米粒子二维周期阵列的光学性质。研究结果表明二维周期阵列的消光性质及其表面等离子共振(SPR)波长受到阵列内粒子组成材料、粒子形状尺寸、阵列周期和阵列排布方式等因素的影响。对于二维正方阵列,当周期较小时(一般小于300 nm),阵列的共振波长主要取决于粒子组成材料和形状尺寸;当周期与阵列单体的共振波长附近时,阵列的消光谱中会出现极窄且锐的SPR共振峰,峰位只与阵列的周期值相关。改变阵列在平行和垂直于入射光偏振方向的周期,可以方便地调节二维长方阵列的共振峰的峰位和峰宽。

Optical Properties of Two Dimensional Periodic Arrays of Gold and Silver Nanoparticles

Recently the two dimensional(2D) arrays of noble metal nanoparticles are substrates frequently-used in molecular detection technology such as surface-enhanced spectroscopy.The optical properties of 2D periodic arrays of gold and silver nanoparticles are studied using the discrete dipole approximation method(DDA).It is found the extinction property and the surface plasmon resonance(SPR) wavelength are both influenced by the composition,shape and size of the nanoparticles,the array period and the array geometries.The resonance wavelength is mainly dependent on the particle composition,shape and size when the period of the 2D square arrays is less than about 300nm.The extinction spectra of the 2D square arrays show very narrow plasmon line shapes and the resonant wavelength is only dependent on the period when the period is near the resonance wavelength of single nanoparticle.The resonance peak position and width of 2D rectangular arrays could be conveniently modulated by changing the periods parallel and perpendicular to the incident polarization.