利用径向指数相同、拓扑电荷数互为相反数的两束高阶径向拉盖尔-高斯光束共轴叠加, 产生了一种新型的复合涡旋光束, 从理论上研究了这种复合涡旋光束的光强分布特性以及空间传播特性, 并进行了实验验证。结果表明: 由高阶径向拉盖尔-高斯光束叠加而成的复合涡旋光束呈多层亮“花瓣”状; 当束腰半径相同时, 随传播距离的增加, 其光强分布呈展宽趋势但不旋转; 当束腰半径不同时, 其光强分布发生旋转, 并出现“旋转拖尾”现象, 旋转方向和“拖尾”方向取决于拓扑电荷数正负及束腰半径大小。研究结果对深入理解复合涡旋光束的产生并进一步拓展其应用范围提供了实验依据。

A new type of composite vortex beam was generated by the coaxial superposition of two high-order radial Laguerre-Gaussian beams with the same radial indices and opposite topological charges. The intensity distribution characteristic and space propagating property of composite vortex beams were studied theoretically and experimentally. The results show that the composite vortex beam, which is superimposed by the high-order radial Laguerre-Gaussian beam, has a multi-layer bright "petal"; When the beam waist radius are same, with the increase of propagation distance, the intensity distribution of the beam spreads but does not rotate; When the waist radius are different, the intensity distribution rotates, and the phenomenon of "rotating tail" appears. The rotating direction and "trailing" direction depend on the number of topological charges and the size of the waist radius. The results provide an experimental basis for understanding the generation of composite vortex beam and further extending its application scope.