Internal motions in femtosecond soliton molecules provide insight into universal collective dynamics in various nonlinear systems. Here we introduce an orbital-angular-momentum (OAM)-resolved method that maps the relative phase motion within a femtosecond soliton molecule into the rotational movement of the interferometric beam profile of two optical vortices. By this means, long-term relative phase evolutions of doublet and triplet soliton molecules generated in an all-polarization-maintaining mode-locked Er-fiber laser are revealed. This simple and practical OAM-resolved method represents a promising way to directly visualize the complex phase dynamics in a diversity of multisoliton structures.

中文翻译：

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使用轨道角动量 (OAM) 分辨方法提取飞秒孤子分子的内相运动

飞秒孤子分子的内部运动提供了对各种非线性系统中普遍集体动力学的洞察。在这里，我们引入了一种轨道角动量 (OAM) 解析方法，该方法将飞秒孤子分子内的相对相位运动映射到两个光学涡旋的干涉光束轮廓的旋转运动中。通过这种方式，揭示了在全偏振保持锁模 Er 光纤激光器中产生的双线态和三线态孤子分子的长期相对相位演化。这种简单实用的 OAM 解析方法代表了一种直接可视化多种多孤子结构中复杂相动力学的有前途的方法。