Gu Bing, Hu Yueqiu, Zhang Xiaohe, Li Miao, Zhu Zhuqing, Rui Guanghao, He Jun, Cui Yiping
Opt Express. 2021 May 10;29(10):14705-14719. doi: 10.1364/OE.423357.
The generation, propagation, and applications of different types of integer vector beams have been extensively investigated. However, little attention focuses on the photophysical and photomechanical properties of the fractional vector beam (FVB). Herein, we theoretically and experimentally investigate the spin angular momentum (SAM) separation and propagation characteristics of weakly focused FVBs. It is demonstrated that such a beam carrying no SAM leads to both the transverse separation of SAM and the special intensity patterns in the focal region. Furthermore, we study the intensity, SAM, and orbital angular momentum (OAM) distributions of the tightly focused FVBs. It is shown that both three-dimensional SAM and OAM are spatially separated in the focal region of tightly focused FVBs. We investigate the optical forces, spin torques, and orbital torques on a dielectric Rayleigh particle produced by the focused FVBs. The results reveal that asymmetrical spinning and orbiting motions of optically trapped particles can be realized by manipulating FVBs.
不同类型整数矢量光束的产生、传播及应用已得到广泛研究。然而，分数矢量光束（FVB）的光物理和光机械特性却很少受到关注。在此，我们从理论和实验上研究了弱聚焦FVB的自旋角动量（SAM）分离和传播特性。结果表明，这种不携带SAM的光束会导致SAM的横向分离以及焦区的特殊强度分布。此外，我们研究了强聚焦FVB的强度、SAM和轨道角动量（OAM）分布。结果表明，在强聚焦FVB的焦区，三维SAM和OAM在空间上是分离的。我们研究了聚焦FVB对介电瑞利粒子产生的光学力、自旋扭矩和轨道扭矩。结果表明，通过操控FVB可以实现光学捕获粒子的不对称旋转和轨道运动。
