依据角向偏振涡旋光束强聚焦有径向分量的结论,修正了角向偏振涡旋光束的强聚焦场公式,重新研究了高阶角向偏振拉盖尔高斯涡旋光束经过衍射光学元件和高数值孔径透镜后的强聚焦特性。结果发现,在焦平面附近获得了新的三维三光链结构(沿着光轴方向的一条三维主光链和对称的两条三维傍轴次光链),详细分析了入射光束缔合拉盖尔多项式的径向模数和光束的拦截比、衍射光学元件结构和聚焦系统的数值孔径对三光链的影响。结果表明,径向模数的改变会破坏三光链结构,通过调控衍射光学元件结构和拦截比可以重新获得对称性更高的三光链结构,从而实现对三光链结构的高自由度调控。

Based on the conclusion that azimuthally polarized vector beam with topological nuclei has radial component after tight focusing, the tight focusing formula of the azimuthally polarized vortex beam is amended. We afresh study the tight focusing properties of the azimuthally polarized higher-order Laguerre-Gauss vortex beams through a diffractive optical element and a high numerical aperture lens. The results show that a new three-dimensional (3D) triple optical chain, composed of a 3D main optical chain and two symmetrical 3D paraxial secondary optical chains, is obtained along optical axis near the focal plane. The effects of the radial mode number of associated Laguerre polynomial and the interception ratio of incident beam, the structure of the diffractive optical element, and the numerical aperture of the focusing lens on the triple optical chain are analyzed in detail. Results show that the change of radial mode number will destroy the structure of triple optical chain. By adjusting the interception ratio and the structure of the diffractive optical element, the triple optical chain with higher symmetry can be obtained again, and the high degree of freedom control of the triple optical chain can be achieved.