Abstract The strong effect that beam polarization has on the performance of industrial laser cutting is well known. The linear and circular polarization states were widely investigated for CO2 lasers. These two states are, in fact, special cases of elliptically polarized laser beams. Theoretical models have predicted an optimal cutting performance for a specific ellipse ratio (b/a = 0,75), but experimental validation was never reported. The main reason is that this characteristic is difficult to obtain in practice. With the technology shift towards solid state lasers, different optical solutions become available for polarization control of high power laser beams (e.g. transmissive beam retarders). This paper reports on the novel design of an elliptically polarized laser beam with a continuous control of the ellipse axes ratio. Starting with a full description of the concept, the equations describing the control of the optical elements are deduced using Jones calculus formalism. A motorized optical module has been built to transform the output of a linearly polarized laser beam into a given elliptic polarization characteristic. Beam analysis equipment was used to validate the experimental setup. Cutting experiments were realized for 2 mm thick 304 L stainless steel and compared with a simulation model. Both results show a comparable nonlinear effect on the achievable maximum cutting speed. The influence of the beam shape is also considered, revealing a strong interaction with the beam polarization. With the help of simulation tools, the applicability of such concept is investigated and, in agreement with the experimental results, the obtained output confirms that the optimal ellipse beam ratio is much closer to b / a = 0 than anticipated in literature.

中文翻译：

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椭圆偏振激光束激光切割的理论和实验方面

摘要 光束偏振对工业激光切割性能的影响是众所周知的。CO2 激光器的线偏振态和圆偏振态被广泛研究。这两种状态实际上是椭圆偏振激光束的特例。理论模型预测了特定椭圆比 (b/a = 0.75) 的最佳切割性能，但从未报告过实验验证。主要原因是这个特性在实践中很难获得。随着技术转向固态激光器，不同的光学解决方案可用于高功率激光束（例如透射光束延迟器）的偏振控制。本文报告了椭圆轴比连续控制的椭圆偏振激光束的新颖设计。从概念的完整描述开始，描述光学元件控制的方程是使用琼斯微积分形式推导出来的。已经构建了一个电动光学模块，以将线偏振激光束的输出转换为给定的椭圆偏振特性。光束分析设备用于验证实验装置。对 2 毫米厚的 304 L 不锈钢进行了切割实验，并与模拟模型进行了比较。两个结果都显示了对可达到的最大切削速度的类似非线性影响。还考虑了光束形状的影响，揭示了与光束偏振的强烈相互作用。在仿真工具的帮助下，研究了这种概念的适用性，并与实验结果一致，