光阑限制飞秒高斯激光光束对微孔加工的影响

Effect of aperture in femtosecond laser optical path on machining of microholes

基于飞秒微孔加工平台,开展了激光加工光路中光阑尺寸对激光微孔加工孔壁质量影响的实验研究,并采用软件仿真和实验结合的方法研究不同光阑限制高斯光束造成的能量波动情况和对实际加工效果的影响。仿真结果表明在光阑光束比小于1.6的情况下高斯光束截面能量分布开始受到影响,高斯光束截面出现能量波动现象。并对不同光阑光束比情况下微孔加工进行实验,实验结果表明:在光阑光束比小于1.6情况下高斯光束截面能量分布发生调制,但是能量波动起初对实际加工影响较小。随着光阑光束比的下降微孔加工孔壁粗糙度增加,当光阑光束比小于0.9时孔壁出现凹槽,孔壁不再光滑,当光阑光束比小于0.7时会严重影响激光加工效率且孔壁质量进一步恶化。

Based on the femtosecond microhole machining platform,the experimental study of the influence of the aperture size on the hole wall quality in laser machining is carried out.The energy fluctuation caused by Gaussian beam with different apertures and its effect on the actual processing effect are studied by the method of software simulation and experiment.The simulation results show that when the ratio of aperture to incident beam is less than 1.6,the energy distribution of the cross-section of the Gaussian beam begins to be affected,and the energy fluctuation appears in the cross-section of the Gauss beam.The experimental results show that the cross-section energy distribution of Gaussian beam is modulated when the ratio of aperture to incident beam is less than 1.6,but the energy fluctuation has little influence on the actual processing at first.With the decrease of diaphragm beam ratio,the hole wall roughness increases.When the ratio of aperture to incident beam is less than 0.9,the hole wall appears grooves,and the hole wall is no longer smooth.When the ratio of aperture to incident beam is less than 0.7,the laser processing efficiency will be seriously affected and the hole wall quality will further deteriorate.