Chowdhury Iftekher S, Roberts Reece P, Molina-Terriza Gabriel, Vidal Xavier
Opt Express. 2019 Apr 15;27(8):11160-11173. doi: 10.1364/OE.27.011160.
Lens-axicon doublets have been used to produce Bessel-Gaussian beams, a narrow non-diffracting beam of relatively constant width. One problem of using Bessel-Gaussian beams is that there is a compromise between achieving a long effective focal length with a small central core radius and distributing the beam intensity between the central core and the off-axis rings. Here, we explore the advantage of tuning the lens-axicon separation, which allows us to have an additional degree of freedom to tailor the beam profile. Moreover, the separation between the lens and the axicon reduces the spherical aberrations in the beam profile, which can then be modeled within the paraxial regime. We study the detrimental effects of the spherical aberrations and provide several options to minimize them. We examine both sharp and shallow axicons used in combination with different converging lenses. We perform a series of detailed experiments to image the structure of the beam through the Bessel region. The spatial light distribution of the lens-axicon system is analyzed by using high dynamic range imaging and complemented with consistent theoretical calculations within the paraxial regime.
透镜-轴棱锥组合已被用于产生贝塞尔-高斯光束，这是一种宽度相对恒定的窄非衍射光束。使用贝塞尔-高斯光束的一个问题是，在以小的中心芯半径实现长有效焦距与在中心芯和离轴环之间分配光束强度之间存在折衷。在此，我们探讨调整透镜-轴棱锥间距的优势，这使我们能够有额外的自由度来调整光束轮廓。此外，透镜与轴棱锥之间的间距减小了光束轮廓中的球差，然后可以在傍轴区域内对其进行建模。我们研究了球差的有害影响，并提供了几种将其最小化的方法。我们研究了与不同会聚透镜组合使用的尖锐和浅轴棱锥。我们进行了一系列详细的实验，以对通过贝塞尔区域的光束结构进行成像。通过使用高动态范围成像分析透镜-轴棱锥系统的空间光分布，并辅以傍轴区域内一致的理论计算。
