具有轨道角动量光束入射下的单球粒子散射研究

根据广义Mie理论，研究了具有轨道角动量拉盖尔-高斯光束（LGB）的空间传输特性以及单粒子散射特性.在单体球粒子对高斯光束散射研究的基础上，分析了在自由空间不同传输距离LGB光束的光强分布情况，在不考虑散射和波束相移关系的情况下，将LGB作为入射高斯光束，通过对波束入射时的散射衰减截面求解得到波束因子，利用矢量球谐函数对入射高斯波束进行展开，从而研究了单球粒子在在轴条件下对具轨道角动量高斯波束入射的散射问题.通过数值计算，讨论了散射强度及角分布在不同波束宽度情况下对其散射特性的影响，并与平面波的情况做了对比.结果表明，当波束束腰半径较小时，束腰半径对衰减率的影响较大，而当束腰半径远大于粒子半径时，接近于平面波的情况. 关键词： 广义Mie理论 轨道角动量 Laguerre-Gauss光束 单球粒子

Scattering of a beam with orbital angular momentum by a single sphere

The propagation properties and scattering characteristic of a beam with orbital angular momentum transmission were researched by using the generalized Lorenz-Mie theory. Based on the research on the scattering of the Gaussian beam from single sphere,the intensity distributions of LGB beam at different propagation distance is analyzed. Without considering the relation between scattering and phase shift, the beam coefficients is obtained by the solution of scattering cross section, and the LGB is expanded in terms of the vector spherical harmonics as fundamental Gaussian beam. The scattering of the beam with orbital angular momentum from single sphere located on the propagation axis is studied. The influence of scattering intensity and angular distribution on scattering characteristic for different beam width is discussed by numerical simulation, and compared with those for the plane wave. The results show that when the beam waist radius is very small,the beam waist radius has serious influence on the decay rate. When the beam waist radius is relatively large,the influence is similar to that of plane wave.