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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。
In this paper, the optical properties of two-dimensional periodic arrays of gold and silver nanoparticles were studied by the discrete point dipole approximation (DDA). The results show that the extinction properties and the surface plasmon resonance (SPR) wavelength of two-dimensional periodic array are affected by such factors as the particle composition, particle shape, array period and array arrangement in the array. For a two-dimensional square array, the resonant wavelength of the array depends mainly on the particle composition and the shape and size of the array when the period is small (typically less than 300 nm); in the extinction spectrum of the array when the period is near the resonance wavelength of the array element Very narrow and sharp SPR formant, peak position only with the array period value. Changing the period of the array parallel and perpendicular to the polarization direction of the incident light can conveniently adjust the peak position and peak width of the formant of the two-dimensional rectangular array.