Self-organized structures in ultrashort pulsed laser processing

超短脉冲激光加工中的自组织结构

• 批准号: 428973857
• 负责人: Professor Dr. Heinz Paul Huber
• 金额: --
• 依托单位: Lehrstuhl für Photonische Technologien (LPT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/428973857?language=en
• 关键词: Self; organized; structures; ultrashort; pulsed

In laser material processing with ultrashort laser pulses (USP) it is neither possible to quantitatively predict processing results nor to control potentially occurring effects like the formation of self-organized structures. Their controlled generation and avoidance is of high interest for production technology. On the one hand they cause a reduction in resolution and an increase in surface roughness; on the other hand changes in the surface structure can lead to useful properties like distinctive hydrophobicity. Therefore, a multi-physical process model to simulate USP processing of metals will be developed and applied in this research project. As intermediate aim, single pulses will be used to analyse if it is possible to completely determine temperature, pressure and density using a transient description of the material heat flows and the equation of states. Furthermore, it will be studied if spallation and phase explosion can be fully explained by a fluid dynamic (CFD) approach. The aim of the project is to explore the formation of self-organized structures like cone-like protrusions (CLP) and laser-induced periodic surface structures (LIPSS) by using multiple-pulses. The influence of intensity variations caused by surface roughness and fluid dynamics on their formation will be studied.The planned project will be organised in three phases. In the first one, a multi-physical USP process model, developed at the Institute of Photonic Technologies (LPT), will be coupled with a model for absorption and heat input, developed at the Lasercenter at the Munich University of Applied Sciences (LHM). Additionally, the equation of state and electronic material parameters will be modelled. A model to calculate the local intensity by solving the Maxwell’s equations will be developed and included. The development of the model will be continuously accompanied by experiments for comparison and iterative model improvement. This leads to a very detailed and comprehensive study of the thermo- and process dynamics, which builds the basic of the project.The second phase focuses on single pulse processing. Using simulations, pump-probe ellipsometry and high-speed videography, the consistency of the model descriptions will be verified and an improvement of the empirical process understanding is expected. The third phase addresses multi-pulse processing. Using simulations, in-situ pump-probe microscopy and SEM and LSM analyses the empirical process understanding of multi-pulse processing will be improved. The focus is kept on the influence of fluid dynamic effects on CLP- and LIPSS-formation and the additional impact of inhomogeneous, periodic energy coupling into the workpiece, caused by interference effects of the surface roughness and by plasmonic effects.

在使用超短激光脉冲（USP）的激光材料加工中，既不可能定量预测加工结果，也不可能控制潜在发生的效应，如自组织结构的形成。它们的控制产生和避免对于生产技术具有高度的意义。一方面，它们会导致分辨率降低和表面粗糙度增加;另一方面，表面结构的变化会导致有用的特性，如独特的疏水性。因此，一个多物理过程模型来模拟金属的USP处理将在本研究项目中开发和应用。作为中间目标，将使用单脉冲来分析是否有可能使用材料热流和状态方程的瞬态描述来完全确定温度、压力和密度。此外，它将研究如果spectrometry和相爆炸可以完全解释的流体动力学（CFD）的方法。该项目的目的是探索通过使用多脉冲形成自组织结构，如锥形突起（CLP）和激光诱导周期性表面结构（LIPSS）。我们会研究由表面粗糙度及流体动力学所引致的强度变化，对它们的形成所造成的影响。在第一个中，在光子技术研究所（LPT）开发的多物理USP过程模型将与慕尼黑应用科学大学（LHM）的Lasercenter开发的吸收和热输入模型相结合。此外，状态方程和电子材料参数将被建模。一个模型来计算局部强度求解麦克斯韦方程组将开发和包括在内。该模型的发展将不断伴随着比较和迭代模型改进的实验。这导致了对热动力学和过程动力学的非常详细和全面的研究，这为项目奠定了基础。第二阶段侧重于单脉冲处理。使用模拟，泵探测椭偏仪和高速摄像，模型描述的一致性将得到验证，并提高经验过程的理解是预期的。第三阶段涉及多脉冲处理。利用模拟、原位泵浦-探测显微镜、SEM和LSM分析，将提高对多脉冲处理的经验过程的理解。重点是保持CLP和LIPSS形成的流体动力学效应的影响和不均匀的，周期性的能量耦合到工件的额外影响，所造成的表面粗糙度的干扰效应和等离子体效应。