球形亚波长粒子中心偏移对散射隐失波光谱密度分布的影响

Influence of Sub-Wavelength Spherical Particle Center Offset on Spectral Density Distribution of Scattered Evanescent Waves

基于散射势理论和弱散射一阶玻恩近似条件,研究了球形亚波长粒子的中心位置偏离和边界条件对散射隐失波光谱密度分布的影响。对散射光的近场分量进行角谱展开,得出了隐失波复振幅的二重积分表达式。利用数值积分方法对角度和径向参量进行积分,得出了隐失波光谱密度与散射体参数之间的关联分布特征。结果显示,在散射体有效半径之内,散射隐失波包含了散射体中心位置和边界条件的特征信息,而该信息将随着传输距离的增大很快消逝。该研究结果有助于复杂空间结构微小粒子的探测和结构反演等。

Based on the scattering potential theory and the first-order Born approximation condition of weak scattering,the influences of the center position offsets and the boundary condition variations of the sub-wavelength spherical particles on the spectral density distribution of the scattered evanescent waves are studied.The near-field components of the scattering light are expanded in the angular spectra,and the double integral expression of the complex amplitude of evanescent waves is obtained.The angular and radial parameters are integrated with the numerical integral method,and the related distribution characteristics between the spectral density of evanescent waves and the scattering parameters are obtained.The results show that the scattered evanescent waves contain the characteristic informations of the center positions and the boundary conditions of the scattered particles whose radii are within the range of the effective scattering radius.These informations disappear rapidly with the increase of propagation distance.The study results are conducive for the detection and structural inversion of tiny particles with complex spatial structures.