均匀椭球粒子对拉盖尔-高斯光束的散射特性研究

Scattering of the Laguerre-Gaussian beam by a homogeneous spheroid

基于广义Mie理论,研究了椭球粒子对在轴入射的拉盖尔-高斯光束的散射特性.通过局域近似法求解椭球坐标系中的波束因子,计算得到了波束因子之间满足的普遍关系.对散射强度随椭球粒子不同尺寸参数和扁圆程度的变化特性进行了数值计算,并针对不同拓扑荷时的散射强度进行了对比分析.结果表明:当椭球粒子尺寸在与入射光波长可比拟的范围内变化时,散射强度随尺寸参数的增大而增大,随椭球长短轴之比和拓扑荷的增大而减小.本文的理论研究能够为拉盖尔-高斯光束在粒径测量、大气激光通信、大气遥感等领域的应用提供更准确的粒子模型和参考价值.

The scattering features of a spheroidal particle illuminated by the Laguerre- Gaussian （LG） beam have been studied based on the generalized Lorenz-Mie theory. By using the localized approximations method, the beam shape coefficients are evaluated and the results obtained agree with the cases of on-axis incidence. Calculations of the far-field scattering intensity are performed to study the LG beam scattered by spheroids, of different size parameters and eccentricities. The simulation results show that when the particle＇s size parameter is within the range that can be compared to the wavelength of the incident light, the magnitude of the scattering intensity will increase as the particle＇s size parameter increases, and it will decrease as the ratio of the spheroid＇s major axis to minor axis increases. Comparisons between LG beams with different topological charges illumination are made and explained physically. It turns out that the magnitude of the scattering intensity decreases as the topological charge increases. The theoretical investigation in this paper may provide a more accurate particle model and reference for applications of LG beams in areas such as particle size measurement, atmospheric laser communication, atmospheric remote sensing and so on.