We consider the behaviour of the orbital angular momentum of the light field as a superposition of Hermite – Gaussian beams upon astigmatic mode conversion. An analytical expression is obtained for the orbital angular momentum of such fields. Expressions are found for various linear combinations of Hermite – Gaussian beams. The astigmatic mode conversion of the initial light fields that are equivalent from the point of view of the orbital angular momentum is shown to lead to significantly different final results.

中文翻译：

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像散模式转换时光场轨道角动量行为的研究

我们将光场的轨道角动量的行为视为 Hermite-Gaussian 光束在像散模式转换时的叠加。得到了此类场的轨道角动量的解析表达式。找到了 Hermite-Gaussian 光束的各种线性组合的表达式。从轨道角动量的角度来看，初始光场的像散模式转换被证明会导致明显不同的最终结果。