模拟分析了分数阶拉盖尔-高斯涡旋光束在远场形成的光强和相位分布,探讨了拓扑荷从分数到整数变化时光束特性的演化过程。光强分布图中出现了两个大小和形状不同的环状光斑,较大的环状光斑上有形状规则的亮斑,环状光斑所围区域内暗斑呈椭圆状,亮斑和暗斑的数量都与入射光的拓扑荷有关。

The intensity and phase distributions of a Laguerre-Gaussian vortex beam possessing fractional topological charge are simulated in the far-field, and the evolution of these optical properties is discussed when the topological charge changes from fraction to integer. We find that there are two rings with different sizes and shapes in the intensity distribution maps. The brighter petal-like spots occur on the larger rings. There are ellipse-like dark spots with low-intensity in the circumscribed area of the rings. The number of bright spots and dark spots is related to the topological charge of the incident vortex beam.