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| 圆对称艾里光束的焦点光强突变性研究 |
| Research on the abruptness of focal intensity of circular Airy beams |
| 投稿时间：2025-02-26 |
| DOI：10.3969/j.issn.1005-5630.202502260037 |
| 中文关键词: 圆对称艾里光束 频谱调制 突变性 |
| 英文关键词:circular Airy beam spectrum modulation abruptness |
| 基金项目:上海市自然科学基金(21ZR1443800) |
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| 中文摘要: |
| 圆对称艾里光束是一种在焦点区域光强发生突变的特殊自聚焦光束，目前研究者通常使用焦点光强峰值与初始面光强峰值的比值衡量这种突变性。本文通过横向对比圆对称艾里光束与另外3种调制光束的自聚焦特性，发现该光强峰值比值为无效参数，无法准确表征焦点区域光强的突变特性，建议改用焦斑纵向半高全宽或纵向光强梯度作为评价指标。同时还发现，不同的调制方法虽然可以大幅提升光束的焦点光强峰值，但对纵向光强梯度的影响很小。通过纵向对比不同光束参数$ {r}_{0} $、$ w $以及$ \alpha $的圆对称艾里光束自聚焦特性，发现提升光束的等效数值孔径可有效增强焦点区域的光强梯度。该研究结果以期为后续圆对称艾里光束的调控提供有益的参考。 |
| 英文摘要: |
| The circular Airy beam is a unique self-focusing beam characterized by abrupt intensity transition in the focal region, where researchers conventionally employ the peak intensity ratio between the focal spot and the initial plane to quantify this transition. Through comparison of self-focusing characteristics among circular Airy beams and three other modulated beams, this study reveals that such peak intensity ratio serves as an invalid parameter for characterizing the abruptness of the intensity in the focal region. We propose substituting it with either the longitudinal full width at half maximum of the focal spot or the longitudinal intensity gradient as evaluation metrics. Furthermore, while different modulation methods can significantly enhance the focal peak intensity, their impacts on longitudinal intensity gradient prove negligible. Comparisons of self-focusing characteristics under varying parameters $ r_{_0} $,$ w $ and $ \alpha $ demonstrate that increasing the equivalent numerical aperture effectively enhances the intensity gradient in the focal region. This investigation provides valuable insights for subsequent manipulation of circular Airy beams. |
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