Simplified freeform optics design for complicated laser beam shaping
Simplified freeform optics design for complicated laser beam shaping
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DOI：
10.1364/ao.56.009308
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发表时间：
2017-11-20
期刊：
影响因子：
1.9
通讯作者：
Wang, Yongtian
中科院分区：
文献类型：
--
作者：
Feng, Zexin;Froese, Brittany D.;Wang, Yongtian
激光束光场的控制，即，激光束成形对于许多激光应用是非常重要的。自由曲面光学器件为复杂的光束整形要求提供了许多优势，包括精确的光束控制、能效、紧凑的结构和相对较低的成本。我们提出了一种改进的光线映射方法，以简化复杂的光场控制的自由曲面光学设计，并实现了一个具有挑战性的任务，产生两个连续的目标平面上的两个规定的光束轮廓。该方法通过计算连接两个规定的光束轮廓的近似输出射线序列和对应的输入射线序列开始。在输入光线序列上设置第一自由曲面的初始轮廓后，我们可以基于给定输入波前和计算出的输出波前之间的光程长度恒定性来获得第二自由曲面。然后，我们可以使用Snell定律获得第一自由曲面光学表面的所有法向量，并通过使用快速最小二乘法求解表面点与法向量之间的关系来近似重构第一自由曲面光学表面。重复表面构造过程，直到满足停止标准。我们设计了三个自由曲面透镜，并通过蒙特卡罗模拟证明了它们能够从发散高斯光束中同时产生两个具有挑战性的光束轮廓。(C)2017美国光学学会
Control of the optical fields of laser beams, i.e., laser beam shaping, is of great importance to many laser applications. Freeform optics offers plenty of advantages for complex beam shaping requirements, including precise beam control, energy efficiency, compact structure, and relatively low cost. We present a modified ray-mapping method to simplify the freeform optics design for complicated optical field control and achieve a challenging task of producing two prescribed beam profiles on two successive target planes. This method begins by calculating an approximate output ray sequence that connects the two prescribed beam profiles and a corresponding input ray sequence. After setting an initial profile of the first freeform optical surface on the input ray sequence, we can obtain the second freeform optical surface based on the optical path length constancy between the given input wavefront and the computed output wavefront. Then, we can acquire all the normal vectors of the first freeform optical surface using Snell's law and approximately reconstruct the first freeform optical surface by solving a relationship between the surface points and normal vectors using a fast least squares method. The surface construction process is repeated until the stop criterion is satisfied. We design three freeform lenses, and Monte Carlo simulations demonstrate their abilities of simultaneously producing two challenging beam profiles from a divergent Gaussian beam. (C) 2017 Optical Society of America