Collaborative Research: A Novel Dual-Pulse Laser Ablation and Plasma Amplification (LAPA) Process for Drilling Non-straight Holes with Arbitrarily Varying Diameters

该基金用于研究一种新型双脉冲激光烧蚀和等离子体放大（LAPA）工艺，用于钻取直径随深度任意变化的非直微孔。许多重要的应用越来越需要这种微孔。然而，他们的精确和高效的钻井仍然是一个巨大的挑战。研究目标是：(1)验证在LAPA中，用第2皮秒激光脉冲放大纳秒激光产生的等离子体可以通过等离子体-侧壁相互作用实现受控的、精确的材料从微孔侧壁去除的假设；(2)了解与LAPA相关的基础物理。具体研究任务包括：(1)建立LAPA的实验装置。(2)建立LAPA理论模型，模拟激光烧蚀和等离子体产生以及激光-等离子体-侧壁相互作用。(3)测量等离子体特性，验证模型，了解LAPA的基本物理过程。(4)在验证模型的指导下进行可行性实验研究。泵浦探针、快速成像和发射光谱技术将用于等离子体特性测量。求解非线性Schrödinger方程和双温流体动力学方程，并结合分子动力学/蒙特卡罗模块对激光-等离子体-空穴侧壁相互作用进行建模。LAPA是PI提出的一种新型制造工艺。其基本的物理过程是皮秒激光脉冲、等离子体（由先前的纳秒激光脉冲产生）和微孔侧壁之间的相互作用，这一过程很少被研究，而且对其理解仍然很差。本项目将结合多尺度建模和综合实验，为这种相互作用提供一个良好的、基本的理解。研究工作将为LAPA的实际应用奠定坚实的科学基础。它还将提高我们对一般意义上的激光-等离子体-材料相互作用的理解，这可能会改善其他现有的或启发新的激光和/或等离子体辅助制造工艺。

This grant provides funding to study a novel dual-pulse laser ablation and plasma amplification (LAPA) process for drilling non-straight microholes with diameters varying arbitrarily with depth. Such kinds of microholes have been increasingly needed by many important applications. However, their precise and efficient drilling still remains a big challenge. The research objectives are to (1) test the hypothesis that in LAPA the amplification of nanosecond-laser-generated plasma by a second picosecond laser pulse can realize controlled and precise material removal from a microhole sidewall through plasma-sidewall interactions and (2) understand the fundamental physics associated with LAPA. The specific research tasks include: (1) Establish an experimental set-up for LAPA. (2) Establish theoretical models for LAPA, which can simulate laser ablation and plasma generation, and laser-plasma-sidewall interactions. (3) Measure the plasma properties to verify the models and understand the fundamental physical processes in LAPA. (4) Perform a feasibility experimental study under the guidance of the verified models. The pump-probe, fast imaging and emission spectroscopy techniques will be used in plasma property measurements. The nonlinear Schrödinger equation and two-temperature hydrodynamic equations will be solved and coupled with a molecular dynamics/Monte Carlo module in modeling the laser-plasma-hole sidewall interactions during LAPA. LAPA is a novel manufacturing process proposed by the PI. Its essential physical process is the interaction among picosecond laser pulse, plasma (generated by a prior nanosecond laser pulse), and microhole sidewall, which has been rarely studied and is still poorly understood. This project will provide a good, fundamental understanding of this interaction by combining multiscale modeling with comprehensive experiments. The research work will build a solid scientific foundation crucial for LAPA's practical applications. It will also improve our understanding of laser-plasma-material interactions in the general sense, which may improve other existing or inspire new laser and/or plasma-assisted manufacturing processes.