The study of beams carrying orbital angular momentum (OAM) has been of interest for its use in free-space optical communications (FSOC), directed energy applications, and remote sensing (RS). For FSOC and RS, it is necessary to measure the wavefront of the beam to recover transmitted or environmental information, respectively. In this computational study, common OAM beams such as the Laguerre–Gaussian (LG), Bessel–Gaussian (BG), and Bessel beams are propagated through atmospheric turbulence and compared to their Gaussian beam counterpart. The turbulence is simulated using multiple phase screens within the framework of a split-step method. Beam metrics used to quantify beam propagation will include the spatial coherence radius, OAM spectrum, on-axis intensity, spot size, divergence, and on-axis scintillation. Atmospheric turbulence along the path is limited to the weak scintillation limit, where beam parameters can be predicted analytically using the Rytov approximation. The results show that BG beams and multiplexed BG beams retain more OAM information than their LG and Bessel beam counterparts. The LG beam on-axis intensity and on-axis scintillation are seen to be independent of OAM mode. The scintillation of the LG beam is less than a BG, Bessel, and Gaussian beam across low- and high-order OAM modes. Insight into these results is discussed through studying the beam divergence, while the initial spot sizes of the Gaussian, LG, and BG beams are limited to the same spatial extent.

中文翻译：

---

不同光束携带轨道角动量的弱湍流效应

携带轨道角动量 (OAM) 的光束的研究因其在自由空间光通信 (FSOC)、定向能应用和遥感 (RS) 中的应用而备受关注。对于 FSOC 和 RS，需要分别测量光束的波前以恢复传输或环境信息。在这项计算研究中，常见的 OAM 光束，例如 Laguerre-Gaussian (LG)、Bessel-Gaussian (BG) 和 Bessel 光束通过大气湍流传播，并与其对应的高斯光束进行比较。在分步法的框架内使用多相屏幕模拟湍流。用于量化光束传播的光束指标将包括空间相干半径、OAM 光谱、轴上强度、光斑尺寸、发散度和轴上闪烁。沿路径的大气湍流仅限于弱闪烁极限，其中光束参数可以使用 Rytov 近似进行分析预测。结果表明，BG 波束和复用 BG 波束比它们的 LG 和贝塞尔波束保留了更多的 OAM 信息。可以看到 LG 光束轴上强度和轴上闪烁与 OAM 模式无关。在低阶和高阶 OAM 模式下，LG 光束的闪烁小于 BG、贝塞尔和高斯光束。通过研究光束发散度来讨论对这些结果的洞察，而高斯光束、LG 光束和 BG 光束的初始光斑尺寸被限制在相同的空间范围内。结果表明，BG 波束和复用 BG 波束比它们的 LG 和贝塞尔波束保留了更多的 OAM 信息。可以看到 LG 光束轴上强度和轴上闪烁与 OAM 模式无关。在低阶和高阶 OAM 模式下，LG 光束的闪烁小于 BG、贝塞尔和高斯光束。通过研究光束发散度来讨论对这些结果的洞察，而高斯光束、LG 光束和 BG 光束的初始光斑尺寸限制在相同的空间范围内。结果表明，BG 波束和复用 BG 波束比它们的 LG 和贝塞尔波束保留了更多的 OAM 信息。可以看到 LG 光束轴上强度和轴上闪烁与 OAM 模式无关。在低阶和高阶 OAM 模式下，LG 光束的闪烁小于 BG、贝塞尔和高斯光束。通过研究光束发散度来讨论对这些结果的洞察，而高斯光束、LG 光束和 BG 光束的初始光斑尺寸被限制在相同的空间范围内。