CDS&E: Nanoconfined Heating via Ultrahigh-repetition-rate Lasers for Enhanced Surface Processing

脉冲激光加工是一种利用超快激光脉冲精确制造三维物体的制造方法。在脉冲激光加工中的可调参数中，激光重复频率(每秒激光脉冲的数量)直到最近才被认为是控制激光烧蚀、烧结和熔化过程的影响深度的关键。这一深度限制决定了用于微纳电子以及航空航天和核应用的脉冲激光技术的分辨率和效率。这个项目的目的是探索当激光重复频率增加到千兆/太赫兹制度时可实现的最小深度。将开发和实施一套先进的计算工具，以了解极端条件下激光与材料的相互作用。该项目的成功完成将使超高重复频率激光能够有限地加热到纳米级，从而提高材料表面纳米层烧蚀、熔化和烧结的精度和效率。研究团队还将在极端情况下开发关于热运输和激光制造的教育项目，以影响和激励广泛的受众，从当地的K-12学生到内华达大学雷诺分校的学生。从该项目开发的开源代码将部署在nanHUB.org上，学术界和工业界都可以访问。该项目的总体目标是预测和控制超高重复频率激光加工中热影响区的深度，模拟极端条件下激光-材料相互作用的独特微观行为，并开发和应用先进的热力学模型来预测材料对激光加工的响应。具体地说，研究小组将开发、验证和共享先进的计算模型，以预测在重复频率高达太赫兹的脉冲激光加热下广泛材料的热传输行为。此外，PI将开发热力学模型--结合相场法、分子动力学和玻尔兹曼输运方程--用于预测超高重复频率激光加工过程中和之后鲜为人知的材料行为和特性。通过该项目将建立超高重复频率激光加工的工艺-结构-性能关系。这些知识将使通过纳米限制加热开发超精密、快速和高效的激光制造技术成为可能。该项目由热传输过程计划和既定的激励竞争性研究计划(EPSCoR)共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Pulsed laser processing is a manufacturing method that uses ultrafast laser pulses to precisely fabricate three-dimensional objects. Among the tunable parameters in pulsed laser processing, the laser repetition rate (the number of laser pulses per second) has only recently been recognized as essential for controlling the affected depth of laser ablation, sintering, and melting processes. This depth limit determines the resolution and efficiency of pulsed laser technologies for micro-/nano-electronics and aerospace and nuclear applications. This project aims to explore the minimum achievable depth when the laser repetition rate increases to the giga-/terahertz regime. A set of advanced computational tools will be developed and implemented to understand the laser and materials interactions under extreme conditions. Successful completion of this project will enable confined heating of ultrahigh-repetition-rate lasers to the nanoscale, thereby improving the precision and efficiency of ablation, melting, and sintering of nano-layers at material surfaces. The research team will also develop education programs on thermal transport and laser manufacturing at the extremes to impact and inspire broad audiences, from local K-12 students to students at the University of Nevada, Reno. Open-source code developed from the project will be deployed at nanoHUB.org and accessible to both academia and industry. The overarching goals of this project are to predict and control the depth of the heat-affected zone during ultrahigh-repetition-rate laser processing, to model the unique microstructure behaviors of laser-material interactions under extreme conditions, and to develop and apply advanced thermomechanical models to predict the material responses to laser processing. Specifically, the research team will develop, validate, and share advanced computational models for predicting thermal transport behaviors for a broad range of materials under pulsed laser heating at repetition rates up to the terahertz regime. Moreover, the PIs will develop thermomechanical models—synergizing the power of the phase field method, molecular dynamics, and Boltzmann transport equations—for predicting the poorly understood material behaviors and properties during and after ultrahigh-repetition-rate laser processing. The process-structure-property relations for ultrahigh-repetition-rate laser processing will be established through this project. Such knowledge will enable the development of ultra-precise, fast, and efficient laser manufacturing technologies via nano-confined heating. This project is jointly funded by the Thermal Transport Processes program and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.