Roulette caustics in transformation optics of structured light beams
Roulette caustics in transformation optics of structured light beams
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DOI：
10.1016/j.optcom.2021.126893
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发表时间：
2021-02
影响因子：
2.4
通讯作者：
G. Ruffato;Hirokazu Kobayashi
中科院分区：
文献类型：
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作者：
G. Ruffato;Hirokazu Kobayashi
携带轨道角动量(OAM)的光束的产生、操纵和探测在从成像到信息和通信技术的广泛应用中具有极其重要的意义。为了达到这一目的，人们设计并实现了光学共形映射，以有效和可控的方式转换光束。在本文中，我们首次分析了结构光束的保角变换产生的焦散，特别是用于OAM复用/排序和乘/除的对数极化映射和圆形扇形变换。利用定相近似下的解析模型和数值模拟，我们展示了产生的焦散线如何在轮盘赌曲线的框架内找到正确的描述，该曲线由围绕相应变换旋转的圆来描述。此外，我们考虑和分析了输入OAM的影响，显示了扭曲波前如何在焦散图案上引入与OAM输入值的量相关的焦散图案的失真。
The generation, manipulation, and detection of beams carrying orbital angular momentum (OAM) have acquired paramount importance in a wide range of applications, from imaging to information and communication technology. To this aim, optical conformal mappings have been designed and implemented to transform light beams in an efficient and controlled way. In this paper, we analyze for the first time the caustics generated by conformal transformations of structured light beams, focusing in particular onlog-polmapping and circular-sector transformations, exploited for OAM multiplexing/sorting and multiplication/division, respectively. Using analytical models in the stationary phase approximation and numerical simulations, we show how the generated caustics find the correct description in the framework of the roulette curves described by a circle rotating around the corresponding transform. In addition, we consider and analyze the effect of the input OAM, showing how the twisted wavefront introduces a distortion on the caustics pattern which can be correlated to the amount of the input value of OAM.