Collaborative Research: Mathematical Modeling and Experimental Study of Femtosecond Laser Machining of High Aspect Ratio Microstructures

这一合作项目的研究目标是开发和验证一个基于物理的模型，以揭示和定量地理解高纵横比微结构中飞秒激光与物质相互作用的基本物理过程。这项研究采用了实验和数学建模相结合的方法。利用泵浦-探测成像、光发射光谱等技术，实验观察了高深宽比微结构中飞秒激光与物质的相互作用。重要的工艺参数，如激光烧蚀率、激光诱导等离子体(由于靶蒸发和/或流体动力学膨胀)和冲击波传播速度、等离子体温度和电子数密度将被测量。该数值模型基于麦克斯韦-S波动方程和流体力学方程的求解，并将通过模拟与测量的对比进行改进和验证，如果该项目成功完成，将为研究大高径比微结构中的飞秒激光与物质的相互作用奠定坚实的科学基础。这将使飞秒激光微加工成为一种直接、灵活、一步到位的技术，可以实现高深宽比微结构的精确和可控生产，这将对微电子机械系统、汽车、航空航天和光学行业产生重大影响，这些行业对高深宽比微结构的需求一直在增加。研究成果将发表在相关期刊上，并在技术会议上展示。将与公司进行直接互动，以传播研究成果。这一跨学科项目为研究生的培养提供了良好的契机。本科生和来自代表性不足群体的学生也将参与该项目。基于该项目成果的动画演示套件将被送往伊利诺伊理工学院附近的高中，那里的少数民族入学率很高。这将促进高中生对理工科的兴趣。

The research objective of this collaborative project is to develop and verify a physics-based model to reveal and quantitatively understand the fundamental physical processes of femtosecond laser-matter interactions in high aspect ratio microstructures. The study employs a combination of experimental and mathematical modeling approaches. Femtosecond laser-matter interactions in high aspect ratio microstructures will be experimentally observed using the pump-probe imaging, optical emission spectroscopy, and other techniques. Important process parameters, such as laser ablation rate, laser- induced plasma (due to the target vaporization and/or hydrodynamic expansion) and shock wave propagation speed, plasma temperature and electron number density, will be measured. The numerical model is based on the solution of Maxwell?s wave equation and hydrodynamic equations, and will be improved and verified by comparing simulations with measurements.If successfully completed, the benefits of this project will be to set up a solid science base for femtosecond laser-matter interactions in high aspect ratio microstructures. This will establish femtosecond laser micromachining as a direct, flexible, and single-step technology that can realize a precise and controlled production of high-aspect ratio microstructures, which will have a big impact on microelectromechanical system, automotive, aerospace, and optics industries, where the demand for high aspect ratio microstructures has been increasing. The research results will be published in related journals and presented at technical conferences. Direct interactions with companies will be performed for research result dissemination. This interdisciplinary project provides a good opportunity for the training of graduate students. Undergraduate students and students from underrepresented groups will also be involved in the project. Animation demonstration kits based on the project results will be sent to the high schools in the neighborhood of Illinois Institute of Technology, which have high minority enrollment. This will promote the interest of high school students in science and engineering.