Opt Lett. 2022 Nov 15;47(22):6037-6040. doi: 10.1364/OL.475818.
Existing methods for probing the orbital angular momentum carried by vortex beams have many limitations and are generally only applicable to specific types of vortex beam. In this work, we present a concise and efficient universal method for probing the orbital angular momentum that is applicable for any type of vortex beam. The vortex beam could range from being fully to partially coherent, with different spatial modes including Gaussian vortex beam, Bessel-Gaussian beam, Laguerre-Gaussian beam, etc., of any wavelength including x rays, matter waves such as electron vortices, and with high topological charge. This protocol only requires a (commercial) angular gradient filter, making it very easy to implement. The feasibility of the proposed scheme is demonstrated both theoretically and experimentally.
现有的探测涡旋光束携带的轨道角动量的方法存在许多局限性，通常仅适用于特定类型的涡旋光束。在这项工作中，我们提出了一种简洁高效的通用方法来探测轨道角动量，适用于任何类型的涡旋光束。该涡旋光束可以是完全相干或部分相干的，具有不同的空间模式，包括高斯涡旋光束、贝塞尔-高斯光束、拉盖尔-高斯光束等，波长范围包括 X 射线、物质波（如电子涡旋），拓扑荷数可以很高。该方案仅需要一个（商用）角向梯度滤波器，因此非常易于实现。理论和实验都证明了所提出方案的可行性。
