532nm短/超短脉冲激光作用于蓝宝石的研究

Study on 532nm Short/Ultrashort Pulse Laser Processing of Sapphire

分别采用波长为532nm的短脉冲激光(脉宽6ns)和超短脉冲激光(脉宽15~20ps)对蓝宝石进行基本作用规律的研究,探究了多/单脉冲烧蚀点直径与功率的关系,分析脉冲数与材料阈值的关系,确定材料阈值。并且对相关作用机理进行系统的对比分析。研究结果表明,烧蚀点直径的平方与脉冲峰值功率的对数呈线性关系,根据关系式计算得出光斑半径与实际测量值相符,并且材料阈值随脉冲数的增加而降低。纳秒绿激光烧蚀蓝宝石材料主要是基于光热作用的机理,而皮秒激光烧蚀蓝宝石材料在以"电子态"冷去除的同时,还兼具一些非线性效应。

Short pulse （6 ns） laser and vltrashort pluse （15-20 ps） laser with wavelength of 532 nm processing of sapphire were studied. The relation between power and diameter of ablated dot by multi/single-pulse machining was explored to make sure the ablation threshold. In addition, systemic comparison of relati＇~e mechanism was discussed. The results showed that the square of ablated dot diameter is proportional to the logarithm of peak pulse laser power. Calculation of the laser spot radius is matched with measured value according to the relation. Besides, the material ablation threshold decreases with the increasing of pulse numbers. The ablation process on sapphire by using 532 nm nanosecond laser is mainly due to the photothermal effect, while the ablation process by picosecond laser was considered to be cold removal based on ＂electronic state＂ as well as nonlinear effects.