大功率激光作用下光学系统轴向焦移仿真  

Simulation of Axial Focal Shift of Optical System Under High-Power Laser

作　　者：丁伟 王菲[1] 王孟洁 翁宁直 Ding Wei;Wang Fei;Wang Mengjie;Weng Ningzhi(School of Opto-Electronics Engineering,Changchun University of Science and Technology,Changchun,Jilin 130022,China)

机构地区：[1]长春理工大学光电工程学院,吉林长春130022

出　　处：《激光与光电子学进展》2021年第11期314-320,共7页Laser & Optoelectronics Progress

基　　金：国家重点研发计划(2018YFB1107500);吉林省科技发展计划(20190302095GX)。

摘　　要：在大功率的光学切割系统中,激光经过光学系统聚焦会产生热量,造成光学系统元件发生热形变和折射率的改变,从而导致镜片焦距发生改变,影响加工效果。利用COMSOL软件对光学系统进行多物理场模型建模,仿真得到连续激光和准连续激光作用下的镜面形变量和折射率改变情况,将镜片受热后数据导入ZEMAX中进行光束追迹,仿真计算出光学系统焦点的轴向偏移量。功率越大,焦点偏移量越大;脉宽越大,焦点偏移量越小;重复频率越高,焦点偏离量越小。最后通过引入对流系数对焦点偏移进行补偿,同时改变对流系数可以控制焦点的位置。该研究解决了大功率激光加工过程中的轴向焦点偏移量测量难的问题,为大功率激光切割设备的焦点控制提供理论依据。In a high-power optical cutting system, the laser is focused by the optical system to generate heat, which causes the optical system components to undergo thermal deformation and change in refractive index, which changes the focal length of the lens and affects the processing effect. COMSOL software is used to model the optical system in a multi-physics field, the shape of the mirror and the change of refractive index under the action of continuous laser and quasi-continuous laser are obtained by simulation. The heated data of the lens is imported into ZEMAX for beam tracing, and the axial offset of the focal point of the optical system is calculated by simulation. The higher the power, the greater the focal shift;the larger the pulse width, the smaller the focal shift;the higher the repetition frequency, the smaller the focal shift. Finally, the focus shift is compensated by introducing the convection coefficient, and the position of the focus can be controlled by changing the convection coefficient. This research solves the problem of difficult measurement of the axial focus offset during high-power laser processing and provides a theoretical basis for the focus control of high-power laser cutting equipment.

关 键 词：激光光学 大功率激光 焦点位移 COMSOL 光束追迹 焦移补偿 

分 类 号：TN249[电子电信—物理电子学]