Sorting orbital angular momentum (OAM) of light is crucial for the success of optical multiplexing systems. Recently, research on OAM sorting has achieved angular separation via photonic momentum transformation. Nevertheless, efficiently sorting dense OAM modes in angular directions still remains challenging. Here, we present a method to implement efficient angular separation of dense OAM modes. A hybrid Fresnel lens in the angular domain and radial domain is used in combination with an OAM multiplier to achieve better mode discrimination and reduced mode overlap. The favorable performance is demonstrated in both simulation and experiment. Our method may find great potential in future optical telecommunications, optical manipulation, and quantum systems.

中文翻译：

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光的密集轨道角动量的有效角分离


光的轨道角动量 (OAM) 排序对于光复用系统的成功至关重要。最近，OAM分选的研究通过光子动量变换实现了角分离。然而，在角度方向上有效地分类密集 OAM 模式仍然具有挑战性。在这里，我们提出了一种实现密集 OAM 模式的有效角分离的方法。角度域和径向域的混合菲涅尔透镜与 OAM 乘法器结合使用，以实现更好的模式辨别和减少模式重叠。仿真和实验均证明了良好的性能。我们的方法可能在未来的光通信、光操纵和量子系统中发现巨大的潜力。