Li Qingfeng, Chambonneau Maxime, Blothe Markus, Gross Herbert, Nolte Stefan
Appl Opt. 2021 May 1;60(13):3954-3963. doi: 10.1364/AO.421945.
In-bulk processing of materials by laser radiation has largely evolved over the last decades and still opens up new scientific and industrial potentials. The development of any in-bulk processing application relies on the knowledge of laser propagation and especially the volumetric field distribution near the focus. Many commercial programs can simulate this, but, to adapt them, or to develop new methods, one usually must create a specific software. Besides, most of the time people also need to measure the actual field distribution near the focus to evaluate their assumptions in the simulation. To easily get access to this knowledge, we present our high-precision field distribution measuring method and release our in-house software InFocus [https://github.com/QF06/InFocus], under the Creative Commons 4.0 license. Our measurements provide 300 nm longitudinal resolution and diffraction limited lateral resolution. The in-house software allows fast vectorial analysis of the focused volumetric field distribution in bulk. Simulations of the linear propagation of light under different conditions (focusing optics, wavelength, spatial shape, and propagation medium) are in excellent agreement with propagation imaging experiments. The aberrations provoked by the refractive index mismatch as well as those induced by the focusing optics are both taken into account. The results indicate that our proposed model is suitable for the precise evaluation of energy deposition.
在过去几十年中，通过激光辐射对材料进行批量加工已取得了长足发展，并且仍展现出新的科学和工业潜力。任何批量加工应用的发展都依赖于对激光传播的了解，尤其是焦点附近的体积场分布。许多商业程序可以对此进行模拟，但是，要对其进行调整或开发新方法，通常必须创建特定的软件。此外，大多数时候人们还需要测量焦点附近的实际场分布，以评估他们在模拟中的假设。为了方便获取这些知识，我们展示了我们的高精度场分布测量方法，并根据知识共享4.0许可发布了我们的内部软件InFocus [https://github.com/QF06/InFocus]。我们的测量提供了300纳米的纵向分辨率和衍射极限横向分辨率。该内部软件允许对批量聚焦体积场分布进行快速矢量分析。在不同条件（聚焦光学器件、波长、空间形状和传播介质）下光的线性传播模拟与传播成像实验结果高度吻合。同时考虑了由折射率失配引起的像差以及由聚焦光学器件引起的像差。结果表明，我们提出的模型适用于精确评估能量沉积。
