皮秒强激光激发蓝宝石成丝引导大切深、近零锥度切片的基础研究

In terms of the greatly increased demanding of ultra-thin sapphire slices and the developing problem of the potential industrial application of high power picosecond laser, based on the filamentation theory of ultra-fast laser transformation in transparent materials, the study on the mechanism and the critical technique of high power picosecond laser (especially for ultraviolet picosecond laser) stimulating filamentation in sapphire by which induces the deep cutting and near-zero taper of laser slicing of the crystal ingot is presented in the project. The formation conditions, mechanism, phenomena and effect laws of the picosecond filamentation will be researched. Phase change or direct slicing of the material will be obtained due to the induction of the filamentation channels. The very thin slice samples of the thickness ＜0.5 mm resulted from deep cut≥10 mm and near-zero taper cutting would be obtained in the project. The theoretical models of the picosecond filamentation and the slicing process can be built on the basis of the systematic study. The research is aimed to provide fundamental scientific and technical support for the development of high-power picosecond laser application in the manufacturing field of ultra-thin sapphire slice or other transparent crystal slices, starting with the innovation of the laser cutting mechanism.

项目针对当前超薄蓝宝石晶片急剧增长的应用需求以及高功率皮秒强激光产业应用优势亟待开发的问题，提出基于透明介质中超快激光传输的成丝理论，开展皮秒强激光激发蓝宝石晶棒成丝、进而引导进行晶棒大切深、近零锥度切片的关键技术及其科学问题研究。探索皮秒强激光（尤其是紫外皮秒强激光）激发蓝宝石的成丝条件、机制、现象和规律，并以成丝等离子通道引导材料相变或直接片状剥离，设计开发蓝宝石晶棒成丝切片的基础工艺，力求在实现≥10 mm大切深和近零锥度成丝切片工艺的基础上获得厚度＜0.5 mm超薄蓝宝石晶棒切片样品，建立相应的成丝机制模型和工艺控制模型。项目以期从激光切割的机制创新入手，为开发皮秒强激光在超薄蓝宝石基片制造业及相似透明晶体基片制造业的应用优势提供基础性研究支撑。

项目基于超快激光在透明介质传输中的成丝机理，研究皮秒强激光成丝诱导实现蓝宝石近零锥度、大切深激光切片技术开发的关键科学问题。面向工程应用的需求发展，探索了工业化皮秒强激光激发蓝宝石的成丝机理、现象和规律。以成丝等离子通道作用于材料的相变或去除效果，获得了皮秒激光成丝切割蓝宝石的优化工艺，建立了相应的作用机制模型和工艺控制模型。项目研发的皮秒激光成丝引导大切深切割技术以皮秒激光（脉宽10 ps）作为成丝激发源，引导自聚焦效应在蓝宝石内部产生突破瑞利长度限制的成丝线迹，利用成丝区域相变而造成材料不同区域间的晶相差异，辅以化学腐蚀，获得了切面粗糙度为800 nm的高精超小蓝宝石切割件，技术可实现自由路径切割。研究分析了皮秒激光成丝特征、技术实现的工艺条件及其中的加工机制，确定了皮秒激光在蓝宝石内自聚焦阈值功率为2.78×106 W，探究了激光峰值功率，聚焦位置以及单点辐照脉冲数量对皮秒激光在蓝宝石内部成丝起始位置和切割质量的影响规律，获得了实现蓝宝石高精切缝的优化工艺参数。该技术为蓝宝石类硬脆材料加工向更厚、更精、自由度更高方向的发展提供了一条值得探索的新途径，为皮秒强激光在超薄蓝宝石基片制造业及相似透明晶体基片制造业应用优势的研发提供基础研究支撑。