The paper reports the intensity characteristics of fractional vortex beam, and controls the coupling between photon orbital angular momentum and spin angular momentum by coherently manipulating Laguerre–Gaussian vortex beam with linearly polarized plane light and its conjugate beam. By comparing theory with experiment, fractional vortex beams with different topological charges are generated by using pure phase liquid crystal spatial light modulator, and their intensity characteristics and interference characteristics are observed. The results show that the radial notch size of the spot is related to the fractional part of the topological charge value, and the closer the fractional part of the topological charge value is to the half integer, the more obvious the radial notch is. With the increase of integer part of topological charge, the spot radius also increases. In addition, interference with linearly polarized plane light reveals that the number of branches is equal to the number of topological charges. Interfere with its conjugate beam, and judge the topological charge number of vortex beam by the relationship between petal number and topological charge number. The petal number of integer vortex beam is twice the topological charge number, and fractional order vortex beam destroys the ring structure of Laguerre–Gaussian beam.

该论文报道了分数涡旋光束的强度特性，并通过线性偏振平面光及其共轭光束相干操纵拉盖尔-高斯涡旋光束来控制光子轨道角动量和自旋角动量之间的耦合。通过理论与实验对比，利用纯相液晶空间光调制器产生具有不同拓扑电荷的部分涡旋光束，并观察其强度特性和干涉特性。结果表明，光斑径向缺口大小与拓扑荷值的小数部分有关，拓扑荷值的小数部分越接近半数，径向缺口越明显。随着拓扑荷整数部分的增加，光斑半径也会增加。此外，线偏振平面光的干涉表明分支的数量等于拓扑电荷的数量。干涉其共轭光束，根据花瓣数与拓扑荷数的关系判断涡旋光束的拓扑荷数。整数涡旋光束的花瓣数是拓扑电荷数的两倍，分数阶涡旋光束破坏了拉盖尔-高斯光束的环结构。