Experimental and theoretical studies of thermally induced aberrations in optical systems for laser material processing

激光源朝着更高功率和更高光束质量的方向发展，由于增加的功率密度和改进的可聚焦性，使得不断有新的应用成为可能。材料加工可以加速，相互作用区域可以减少，到工件的距离可以扩大。然而，用于激光束引导和成形的光学元件暴露于高的热负荷，其甚至由于小型化的趋势而日益加剧。结果，元件的机械和光学性质发生变化。所产生的光学系统的波前像差降低了用于激光加工的光束质量，并且还恶化了经常需要的光学同轴加工控制。高亮度光束源的优点，因此，目前还没有穷尽used.The项目建议书的目标是生成的基本原理的热光学系统的成像质量的热光学影响的耦合multiplier模拟高功率激光系统。因此，光学系统的设计应能够抵抗热干扰因素。因此，需要光线跟踪和有限元分析（FEA）的算法耦合，以便能够基于表征的玻璃材料、涂层、安装件和其他部件来模拟热致波前像差。最重要的科学研究问题是确定能量输入和输出，离散数值结果的算法插值，以提供射线跟踪模拟中的FEA结果，以及热致波前变形的计算。如果能够开发出一个稳健的模型，就可以采取优化、瞬态行为计算和热效应补偿的步骤。

The development of laser sources towards higher power and improved beam quality enables constantly new applications due to increased power densities and improved focusability. Material processing can be sped up, interaction zones can be reduced and the distance to the workpiece can be enlarged. However, optical elements used for laser beam guiding and shaping are exposed to high thermal loads, which are even increasingly aggravated by the trend for miniaturization. In the consequence, mechanical and optical properties of the elements change. Resulting wave front aberrations of the optical system reduces the beam quality used for the laser processing and also deteriorates an often required optical coaxial process control. The advantages of high brilliant beam sources are thus currently not exhaustively used.The objective of the project proposal is the generation of fundamentals for a coupled multiphysic simulation of thermo-optical influences onto the imaging quality of optical systems for high power laser systems. Thus, the design of optical systems shall be enabled which are robust against thermal disturbance factors. Therefore, an algorithmic coupling of ray tracing and finite element analysis (FEA) is required, in order to enable the simulation of thermally induced wave front aberrations based on characterized glass materials, coatings, mounts and further components. The most important scientific research questions address the determination of energy input and output, the algorithmic interpolation of discret numerical results for providing FEA results in ray tracing simulation and the computation of thermally induced wave front deformations. If a robust model can be developed, steps towards optimization, computation of transient behavior and compensation of thermal effects can be taken.