Collaborative Research: Modeling and Analysis of High Energy Ultrashort Laser-Induced Plasmas and Shockwave

0853528 Wu该项目的目标是通过建模和实验，了解并控制高能超短激光与固体相互作用过程中等离子体和冲击波形成的能力。特别是，早期的等离子体附近发生的固体表面，是由高能量，超短激光束照射将进行研究。一个目标是控制冲击波和等离子体性质，使得它们可以被利用来产生诸如细丝效应的新颖结果，即，由自聚焦和等离子体散焦之间的动态平衡引起的等离子体颤动的形成。这项研究将使激光与物质相互作用的合适建模技术的发展与超短，高功率激光的使用。 将发展一个多尺度混合模型来研究早期等离子体的形成及其与激光束和靶表面的相互作用。 对于早期等离子体的形成，将开发一个结合分子动力学和蒙特卡罗模型（MD/MC）来计算中性粒子，电子，离子，光子和声子的动力学，同时考虑这些粒子之间的相互作用。 由于组合MD/MC的时间和空间计算域的大小是有限的，因为计算的复杂性，MD/MC将接口的有限差分模型的域深处的目标材料，也接口的流体动力学方程的域以上的目标表面建模的等离子体/环境空气区域。这种组合模型将揭示有关早期等离子体形成及其与激光束和靶表面相互作用的详细信息。在配套实验研究中，将利用干涉图和阴影图技术，实现对不同延迟时间的激光等离子体和冲击波的更全面测量和观测。实验结果将用于验证模型。高能量超短激光器的应用范围从薄膜的脉冲激光制造到激光微/纳米制造。 提高对高能超短激光与材料相互作用的理解可以显著扩展这些器件的潜在应用。这项研究将产生与未来开发适用于特定应用的激光器相关的信息。研究结果将在以工业界和学术界为对象的会议上以及在一个专门的网站上广泛传播。一些本科生将通过夏季本科研究奖学金（SURF）计划由普渡大学工程学院管理，以及通过本科生独立项目参与。 将通过现有的方案，如妇女参与工程方案（WIEP）和少数民族工程方案（MEP），促进代表性不足的学生的参与。这项研究将被纳入一个本科制造类，制造工艺的原理和实践。 在伊利诺伊理工学院（IIT），新的发现将被纳入一个名为先进制造工程类。本科生和少数民族研究生将通过本科生研究奖学金计划和IIT的专题课程参与。基于该项目的动画演示套件将与芝加哥公立学校学生科学博览会分享，以吸引更多的学生（特别是少数民族学生）从事科学和工程。

0853528WuThe goal of this project is to develop an understanding of, and ability to control plasma and shock wave formation during high energy, ultrashort laser-solid interaction via modeling and experimentation. In particular, the early plasma that occurs near a solid surface that is irradiated by high energy, ultrashort laser beams will be investigated. A goal is to control the shock wave and plasma properties so that they may be exploited to create novel results such as filament effects, i.e., formation of a plasma chatter that results from the dynamic balance between self-focusing and plasma de-focusing. The research will enable development of a suitable modeling technique for laser-matter interaction that is associated with the use of ultrashort, high power lasers.Intellectual Merit. A multi-scale hybrid model will be developed to investigate the early plasma formation, its interaction with the laser beam and the target surface. For the formation of early plasma, a combined molecular dynamics and Monte Carlo model (MD/MC) will be developed to calculate the dynamics of neutrals, electrons, ions, photons and phonons, while considering the interactions among these particles. Since the temporal and spatial computation domain sizes of the combined MD/MC are limited because of computational complexity, the MD/MC will be interfaced with a finite difference model for the domain deep inside the target material, and also interfaced with the hydrodynamic equations for the domain above the target surface to model the plasma/ambient air region. This combined model will reveal detailed information about early plasma formation, and its interaction with the laser beam and the target surface. In the companion experimental study, the interferogram and shadowgraph techniques will be used to realize a more comprehensive measurement and observation of laser-generated plasma and shock waves at different delay times. The experimental results will be used for the validation of the model.Broader Impacts. High energy, ultrashort lasers have applications ranging from pulsed laser fabrication of thin films to laser micro/nano fabrication. Improving the understanding of high energy ultrashort, laser-material interaction can significantly expand the potential applications of these devices. The research will yield information relevant to the future development of suitable lasers for specific applications. The research results will be broadly disseminated at conferences targeted to both industrial and academic audiences, as well as at a dedicated web site. Several undergraduate students will be involved through the summer undergraduate research fellowship (SURF) program administered by the College of Engineering at Purdue, as well as through undergraduate independent projects. Involvement of underrepresented students will be pursued through existing programs such as Women in Engineering Program (WIEP) and the Minority Engineering Program (MEP). The research will be incorporated into an undergraduate manufacturing class, Principles and Practice of Manufacturing Processes. At the Illinois Institute of Technology (IIT), the new findings will be incorporated into a class entitled Advanced Manufacturing Engineering. Undergraduates and minority graduate students will be involved through the Undergraduate Research Fellowships program and a Special Topics class at IIT. Animation demonstration kits based on the project will be shared with the Chicago Public School Students Science Fair, to attract more students (particularly minority students) to become engaged in science and engineering.