Peng Xiaofeng, Wang Haiyun, Liu Lin, Wang Fei, Popov Sergei, Cai Yangjian
Opt Express. 2020 Oct 12;28(21):31510-31523. doi: 10.1364/OE.408357.
Twisted Laguerre-Gaussian Schell model (TLGSM) beams are a novel type of partially coherent beams, which carry the twist phase and the vortex phase simultaneously. In this paper, the self-reconstruction (SR) of the TLGSM beam partially blocked by an opaque obstacle and propagating through a thin lens focusing system is studied in detail. Implementing the pseudo-mode expansion method, we represent the TLGSM beam as a superposition of spatially coherent modes, which is applicable for calculating the cross spectral density (CSD) and spectral degree of coherence (SDOC) of such a beam using the Fourier transform. The numerical results reveal that the twist parameter, a measure of the strength of a twist phase, determines the characteristics of the SR. In the case of the topological charge of the vortex is positive, the SR capability of spectral density is significantly improved with the increase of the twist parameter. The physical mechanism behind these phenomena is analyzed in detail from the point view of mode expansion. Further, the dependence of the side ring intensity and SR capability of the SDOC on the twist parameter are also investigated. It is found that the SR capability and side ring intensity of the SDOC are simultaneously enhanced for a large twist parameter, providing an efficient way to determine the number of topological charge. Our study results may find application in communication and information recovery applications.
扭曲拉盖尔 - 高斯谢尔模型（TLGSM）光束是一种新型的部分相干光束，它同时携带扭曲相位和涡旋相位。本文详细研究了被不透明障碍物部分遮挡并通过薄透镜聚焦系统传播的TLGSM光束的自重建（SR）。采用伪模展开方法，我们将TLGSM光束表示为空间相干模的叠加，这适用于使用傅里叶变换计算此类光束的交叉谱密度（CSD）和光谱相干度（SDOC）。数值结果表明，扭曲参数作为扭曲相位强度的一种度量，决定了自重建的特性。在涡旋拓扑电荷为正的情况下，随着扭曲参数的增加，光谱密度的自重建能力显著提高。从模式展开的角度详细分析了这些现象背后的物理机制。此外，还研究了SDOC的边环强度和自重建能力对扭曲参数的依赖性。发现对于较大的扭曲参数，SDOC的自重建能力和边环强度同时增强，这为确定拓扑电荷数提供了一种有效方法。我们的研究结果可能在通信和信息恢复应用中找到应用。
