纳秒激光加工石英微通道的实验与理论研究

Research on the Fabrication of Micro Channels in Fused Silica Substrates by Nanosecond Laser

利用调Q Nd…YAG激光器输出的1064nm纳秒脉冲激光聚焦在石英上,分别采用激光热加工法和激光诱导等离子体法加工微通道。热加工的通道长度可控,通道周围产生热裂纹;诱导等离子体加工的微通道内壁光滑,通道深度可达4mm。研究了激光热加工微通道时的温度场和热应力分布,分析了激光诱导等离子体加工微通道的过程。研究表明,激光热加工时温度场的存在导致热应力的产生,热应力超过石英断裂阈值使石英发生炸裂,导致微通道的形成及热裂纹的产生;激光诱导等离子体法由于等离子体屏蔽效应产生的高温等离子体烧蚀石英形成微通道,避免了热裂纹的产生。

A Q-switched Nd…YAG laser is used to fabricate micro channels in a fused silica substrate by thermal induced processing and laser-induced plasma processing.The length of micro channels by thermal induced processing can be controlled and there are many thermal cracks around the channel.The interior wall of the micro channels drilled by laser-induced plasma is smooth,and the depth of the channel is up to 4 mm.The temperature and thermal stress distributions of thermal induced processing are calculated,and the behavior of laser-induced plasma processing is studied.The results indicate that as a result of great temperature changes,the thermal stress is larger than the fracture strength of sample,which leads to the formation of the channel and the thermal cracks.The ablation of the high temperature plasma formed by plasma shielding effects leads to a micro channel of high quality with a smooth internal surface and no thermal cracks.