基于直角锥面变形镜的薄管激光光束质量提升新方法  

Novel method of improving beam quality of thin-wall tube laser based on right-angle cone deformable mirror

作　　者：何婷 田博宇 邱蝶 张彬[1] He Ting;Tian Bo-Yu;Qiu Die;Zhang Bin(College of Electronics and Information Engineering,Sichuan University,Chengdu 610064,China)

机构地区：[1]四川大学电子信息学院,成都610064

出　　处：《物理学报》2021年第17期397-405,共9页Acta Physica Sinica

基　　金：四川省科技计划项目(批准号:2018JY0553);中国科学院自适应光学重点实验室基金(批准号:LAOF1801)资助的课题.

摘　　要：针对大遮拦比窄环宽薄管激光光束质量提升需求,提出了一种基于直角锥面变形镜的薄管激光光束质量提升新方法.采用直角锥面实现薄管激光离轴像差的自校正,再利用驱动单元控制直角锥面变形镜的形变来进一步校正残余像差,进而实现对薄管激光光束质量的提升.以48单元直角锥面变形镜为例,利用有限元分析方法建立了直角锥面变形镜的物理模型,分析了直角锥面变形镜对薄管激光畸变波前的校正能力.结果表明,基于直角锥面变形镜的薄管激光光束质量提升新方法能够有效校正大遮拦比窄环宽薄管激光的波前畸变,显著提升薄管激光光束质量.Aiming at improving the beam quality of thin-wall tube laser,a novel method based on the right-angle cone deformable mirror is proposed.In the method,a reflector with inner right-angle conical surface is used,and the annular laser beam successively passes through the opposite sides of the tube,compensating for the off-axis aberrations of the annular laser beam.Next,the residual aberrations are corrected by the deformation of the right-angle cone mirror to further improve the beam quality.The physical model of the right-angle cone deformable mirror is built up by using the finite element analysis method,followed by optimizing the structural parameters of the right-angle cone deformable mirror.The preliminarily optimized right-angle cone deformable mirror drived by 48 actuators with a radius of 1.5 mm for each actuator and an interval of 11 mm between actuators is then utilized to correct the beam quality of the thin-wall tube laser.Results indicate that the output beam quality of the thin-wall tube laser degrades rapidly with the increasing of the tube’s concentricity error,parallelism error,taper error and source’s parallelism error.Fortunately,the beam quality is significantly improved by using the right-angle cone deformable mirror and the b factor greatly decreases.In addition,the performance of the non-ideal right-angle cone deformable mirror with a 20-μrad taper error and a 10-mrad collimation error is compared with that of the ideal mirror,and the results show that the β factor is controlled within 1.14 after having been corrected by the non-ideal right-angle cone deformable mirror.Therefore,the simulation results theoretically prove that the novel method can effectively eliminate the typical aberrations caused by the errors from fabrication and alignment and correct the wavefront distortion of the large-aperture thin-wall tube laser,thus significantly improving the beam quality.

关 键 词：薄管激光 直角锥面变形镜 光束质量 自适应光学 

分 类 号：TN24[电子电信—物理电子学]