运用广义洛伦兹-米散射理论(GLMT)研究了高阶矢量贝塞尔涡旋波束的单球形气溶胶粒子的散射特性,将直角坐标系下沿 z轴方向传播的贝塞尔波束的电磁场强度各分量表达式转化成球坐标系下各个分量的表达式,使用GLMT中的积分局部近似法计算贝塞尔涡旋波束的波束因子,进而计算在轴入射的高阶矢量贝塞尔涡旋波束的单球形气溶胶粒子散射。以硝酸铵球形粒子为例,通过数值计算,讨论了不同拓扑荷数和半圆锥角矢量贝塞尔涡旋波束与气溶胶粒子作用的微分散射截面随散射角变化的分布,以及消光截面、散射截面和吸收截面随均匀球形气溶胶粒子尺寸参数的变化情况。结果表明,随着贝塞尔涡旋波束拓扑荷数的增大,粒子微分散射截面值逐渐减小;拓扑荷数一定的贝塞尔涡旋波束随着光束半圆锥角的增大,消光截面、散射截面和吸收截面各值整体上趋向减小。

Herein, based on generalized Lorenz-Mie theory (GLMT), the scattering characteristics of single spherical aerosol particles illuminated by a high-order vector Bessel vortex beam are investigated. The electromagnetic field expression of each component of the Bessel vortex beam propagating along z axis in a rectangular coordinate system is transformed into an expression of each component in the spherical coordinate system. The beam factors of the Bessel vortex beam are calculated by the integral localized approximation method in GLMT, and then the scattering of single spherical aerosol particles illuminated by the axially-incident Bessel vortex beam is calculated. Taking the ammonium-nitrate spherical particles as examples, the distribution of variation in the scattering angle for the differential scattering cross-section of the interaction between aerosol particles and vector Bessel vortex beams which have different topological charges and half-cone angles are discussed by numerical calculation. Furthermore, variations of the extinction, absorption, and scattering cross-sections with the size parameters of uniformly spherical aerosol particles are discussed as well. Results show that, with increasing topological charge of the Bessel vortex beam, the differential scattering cross-section of particles gradually decreases; the absorption, scattering, and extinction cross-sections of the vector Bessel vortex beam with a certain topological charge overall trend to decrease as the half-cone angle of the beam increases.