Computational Investigation of Short Laser Pulse Nanostructuring of Dielectric Materials.

介电材料的短激光脉冲纳米结构的计算研究。

• 批准号: 336533159
• 负责人: Dr. Dmitry Ivanov
• 金额: --
• 依托单位: Theoretische Physik II: Festkörper und Ultrakurzzeitphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/336533159?language=en
• 关键词: Computational; Investigation; Short; Laser; Pulse

Since recently ultrashort laser pulse irradiation has become a beneficial tool in achieving controlled laser-induced matter transformations and found a variety of applications in laser processing technologies such as generating three-dimensional structures, creation of color centers, and development of micro optics. With the help of femtosecond laser techniques, waveguiding objects were created in fused silica, which is one of the commonly used optical materials in both IT- and Bio-technologies.The interaction of ultrashort laser pulses with dielectrics, however, involves a number of competing non-equilibrium processes that can be activated in a wide range of temporal and spatial scales. The transient character of laser-induced phase transitions, occurring under conditions of strong superheating on a pico- and sub pico-second time scales and in the presence of strong pressure and temperature gradients, can result in ultrafast melting, spallation, ablation, and breakdown processes. Understanding of all these processes on an atomic scale and being able to precisely simulate them for predicting material behavior and hence designing new nano-technology applications requires a robust fundamental theory. In this project we propose to develop a combined computational method suitable for the investigation of the interaction of ultrashort laser pulses with dielectric solids. The effect of photo-excited free carrier dynamics will be described in the framework of a continuum approach, whereas the kinetics of laser-induced non-equilibrium phase transformation processes will be addressed at atomic level with the Molecular Dynamics (MD) method. For this purpose, the project assumes a close collaboration between the groups of Prof. Rethfeld (TU-Kaiserslautern) and the group of Prof. Garcia (University of Kassel). The laser-induced processes, constituting free carrier dynamics, will be thoroughly studied and described in the form of numerical blocks (for incorporation into MD code) in the group of Prof. Rethfeld. The corresponding MD interatomic potential, on the other hand, will be modified in the group of Prof. Garcia to account for interatomic bond weakening and description of the laser-induced non-thermal effects. The developed model will be applied to study the mechanism of ultrashort pulse laser-induced damage of dielectrics on the example with fused silica and crystalline beta-SiO2, which is of enormous technological relevance. Realized in large scale MD simulations, our proposed approach is expected to capture the above mentioned mechanisms and have a strong impact on both the fundamental understanding of the nanostructuring processes induced in dielectric solids and their possible technological applications.

近年来，超短激光脉冲辐照已成为实现可控激光诱导物质相变的一种有利工具，并在激光加工技术中得到了广泛的应用，如产生三维结构、创建色心和发展微光学。在飞秒激光技术的帮助下，在信息技术和生物技术中常用的光学材料之一的熔融二氧化硅中产生了光波导对象。然而，超短激光脉冲与介质的相互作用涉及许多相互竞争的非平衡过程，这些过程可以在广泛的时间和空间尺度上被激活。激光诱导相变的瞬变特征发生在皮秒和亚皮秒的强过热条件下，并且存在强的压力和温度梯度，可以导致超快的熔化、层裂、烧蚀和击穿过程。理解原子尺度上的所有这些过程，并能够准确地模拟它们以预测材料行为，从而设计新的纳米技术应用，需要强大的基础理论。在这个项目中，我们建议发展一种适合于研究超短激光脉冲与介质固体相互作用的组合计算方法。光激发自由载流子动力学的影响将在连续介质方法的框架内描述，而激光诱导的非平衡相变过程的动力学将用分子动力学(MD)方法在原子水平上进行研究。为此，该项目假定雷斯菲尔德教授小组(TU-Kaiserslautern)和加西亚教授小组(卡塞尔大学)之间进行密切合作。构成自由载流子动力学的激光诱导过程将在Rethfeld教授的小组中以数值块(并入MD代码)的形式被彻底研究和描述。另一方面，在Garcia教授的团队中，相应的MD原子间势将被修改，以解释原子间键的减弱和对激光诱导的非热效应的描述。该模型将用于研究超短脉冲激光对电介质的损伤机理，并以熔融二氧化硅和结晶型β-二氧化硅为例，具有很强的技术意义。在大规模的分子动力学模拟中，我们提出的方法有望捕捉到上述机制，并对介电固体中诱导的纳米结构过程的基本理解及其可能的技术应用产生强烈的影响。