Liu Leixin, Wang Haiyun, Liu Lin, Ye Yan, Wang Fei, Cai Yangjian, Peng Xiaofeng
Opt Express. 2022 Feb 28;30(5):7511-7525. doi: 10.1364/OE.452147.
We introduce a new type of partially coherent vector beam, named the radially polarized twisted partially coherent vortex (RPTPCV) beam. Such a beam carries the twist phase and the vortex phase simultaneously, and the initial state of polarization (SOP) is radially polarized. On the basis of the pseudo-modal expansion and fast Fourier transform algorithm, the second-order statistics such as the spectral density, the degree of polarization (DOP) and the SOP, propagation through a paraxial ABCD optical system are investigated in detail through numerical examples. The results reveal that the propagation properties of the RPTPCV beam closely depends on the handedness of the twist phase and the vortex phase. When the handedness of the two phases is same, the beam profile is easier to remain a dark hollow shape and the beam spot rotates faster during propagation, compared to the partially coherent vortex beam or the RPTPCV beam with the opposite handedness of the two phases. In addition, the same handedness of two phases resists the coherence induced de-polarization of the beam upon propagation, and the SOP is also closely related to the handedness, topological charge of the vortex phase and the twist factor of the twist phase, providing an efficient way to modulate the beam's DOP and SOP in the output plane. Moreover, we establish an experiment setup to generate the RPTPCV beam. The average spectral density and the polarization properties are examined in the experiment. The experimental results agree reasonable well with the theoretical predictions. Our results will be useful for particle manipulating, free-space optical communications, and polarization lidar systems.
我们引入了一种新型的部分相干矢量光束，称为径向偏振扭曲部分相干涡旋（RPTPCV）光束。这种光束同时携带扭曲相位和涡旋相位，并且初始偏振态（SOP）是径向偏振的。基于伪模式展开和快速傅里叶变换算法，通过数值示例详细研究了诸如光谱密度、偏振度（DOP）和SOP等二阶统计量在傍轴ABCD光学系统中的传播。结果表明，RPTPCV光束的传播特性密切依赖于扭曲相位和涡旋相位的旋向。当两个相位的旋向相同时，与部分相干涡旋光束或两个相位旋向相反的RPTPCV光束相比，光束轮廓在传播过程中更易于保持暗空心形状，并且光斑旋转得更快。此外，两个相位相同的旋向会抑制光束在传播过程中因相干导致的去偏振，并且SOP也与旋向、涡旋相位的拓扑电荷以及扭曲相位的扭曲因子密切相关，这为在输出平面中调制光束的DOP和SOP提供了一种有效方法。此外，我们建立了一个实验装置来产生RPTPCV光束。在实验中检测了平均光谱密度和偏振特性。实验结果与理论预测相当吻合。我们的结果将对粒子操控、自由空间光通信和偏振激光雷达系统有用。
