高频率皮秒激光微加工石英衬底铝膜效率

采用重复频率100 kHz下,输出功率为3.7 W的532 nm Nd:YAG皮秒激光器对石英衬底微米量级的铝膜进行了烧蚀,研究了脉宽为10 ps的激光单脉冲能量密度对烧蚀效率、光斑耦合率对烧蚀图形以及重复加工次数对加工精度的影响。单脉冲激光烧蚀实验证实,皮秒激光烧蚀铝膜可分为高能量密度烧蚀与低能量密度烧蚀两个区域。光斑耦合率对烧蚀深度影响较大,不易从理论角度控制烧蚀效率。为提高加工精度与验证求解烧蚀率的准确性,提出重复多次加工的方法。对比了高斯线性法与高斯线性修正法的求解烧蚀率的结果,证明了高斯线性修正法在扫描激光精细加工方面的优越性。利用高斯线性修正法求得的烧蚀效率,模拟了激光在不同光斑耦合率下烧蚀微槽的三维轮廓图。

Ablation rate of high frequency picosecond laser micromachining quartz substrated Al film

A 532 nm Nd:YAG 10 ps laser with output power of 3.7 W under frequency of 100 kHz was used for ablating quartz glass substrated Al film with thickness of micron dimension. The relationship between ablation rate and single pulse laser fluence was studied, the high fluence ablation and low fluence ablation regimes for picosecond laser ablating Al film were defined. The effect of spot overlapping rates on profilograms of grooves was analyzed, results showed that the ablation depth changed greatly with spot overlapping rate, and it was difficult to obtain ablation rate theoretically from this experiment. In order to improve the precision of ablated grooves and validate the accuracy of obtained ablation rate from Gaussian Linear method(GL), a muti-pass ablating method was put forward. The ablation rates calculated from GL were compared with Corrected Gaussian Linear method(CGL), experimental results showed that CGL was suitable for calculating ablation rates of grooves. The 3D profilogram of grooves in Al film ablated by 10 ps at different spot overlapping rates were simulated through CGL calculated ablation rates.