基于电子激发/电离调控的飞秒脉冲序列宽禁带材料微孔加工

宽禁带材料微孔是能源、国防、生物等领域核心部件。飞秒激光以其脉冲时间超短，峰值功率超高等优势已在宽禁带材料微孔加工中获得了一定的应用。然而，飞秒脉冲能量小，加工效率较低；同时工业生产及应用中对微孔加工质量、极限尺寸等要求不断提高，对其工艺提出新的挑战。飞秒激光脉宽短于多数物理化学过程特征时间，高效率高品质微孔加工的关键在于调控飞秒激光与宽禁带材料相互作用中电子激发/电离过程。本项目以飞秒激光脉冲序列调控电子激发/电离为手段，深入研究宽禁带材料在飞秒激光脉冲序列作用下的电子激发/电离过程；建立微孔形成过程中脉冲序列及宽禁带材料参数下时域演化的能量耦合及电子激发/电离模型，研究其对后续宽禁带材料瞬时局部特性及相变微观机理；系统研究飞秒激光脉冲序列各个参数对电子激发/电离的可控性，揭示其对微孔加工过程及其结果的影响机理，为形成一种面向宽禁带材料高效率高质量微孔加工新方法奠定理论基础。

The micro-hole structures in wide bandgap materials are key components in fields like energy, national defense, biology and so on. Femtosecond laser has been used for the fabrication of micro-holes in wide bandgap materials mainly due to its ultra-short pulse duration and ultra-high peak energy. However, the average power of femtosecond pulse is rather low, which leads to low drilling efficiency. Meanwhile, the demands for drilling quality and super diffraction limit feature size of micro-holes in industrial applications get higher and higher. All of above challenge the technology of femtosecond laser hole-drilling. Due to the ultra-short pulse duration of femtosecond laser which is shorter than most characteristic time of physical or chemical processes, the key point of high-efficiency and high-quality hole-drilling is to control the electron excitation/ionization process during the interaction between femtosecond laser and wide bandgap materials. The control of electron excitation/ionization by femtosecond laser pulse trains being the original methodology, this project is aiming at: (1) lucubrating the electron excitation/ionization process within wide bandgap materials under femtosecond laser pulse trains; (2) establishing models of temporally evolutional energy coupling and electron excitation/ionization during the formation of micro-holes, and investigating the transient localized properties change and the microscopic phase change mechanism; (3) researching the controllability of electron excitation/ionization under femtosecond laser pulse trains systematically and revealing its influence on micro-hole fabrication process and results in order to establish the theoretical foundation of a novel method of high-efficiency and high-quality hole drilling in wide bandgap materials.