“之字形”光路薄管固体激光大气长程传输光束质量分析  

Beam quality analysis of solid-state zigzag tube lasers for long-distance propagation in atmosphere

作　　者：张彬[1] 田博宇 何婷 张小民[2] Zhang Bin;Tian Boyu;He Ting;Zhang Xiaomin(School of Electronics and Information Engineering,Sichuan University,Chengdu 610064,China;China Academy of Engineering Physics,Mianyang 621900,China)

机构地区：[1]四川大学电子信息学院,成都610064 [2]中国工程物理研究院,四川绵阳621900

出　　处：《强激光与粒子束》2021年第8期95-104,共10页High Power Laser and Particle Beams

基　　金：四川省科学计划资助项目(2018JY0553);中国科学院自适应光学重点实验室基金(LAOF1801)。

摘　　要：“之字形”光路薄管固体激光是一种结构紧凑、增益高且利于发射的新型激光光源。针对薄管固体激光光源及其大气长程传输过程中的光束质量退化问题,提出了基于直角锥面变形镜的薄管激光校正方法,进而通过建立薄管激光校正模型以及大气长程传输模型,开展了薄管激光大气长程传输光束质量分析。首先,针对大遮拦比窄环宽环形光束与发射系统的匹配问题,提供了一种薄管激光环形光束整形变换方案,有效实现了薄管激光的整形和变换。然后,分析了薄管激光光源光束质量、大气湍流效应和热晕效应等对整形变换后的薄管激光大气长程传输特性的影响,进而明确了薄管激光大气长程传输光束质量退化机理。最后,分析了直角锥面变形镜对薄管激光的光源畸变、大气湍流的低频分量和热晕导致的离焦相位等的校正效果。结果表明,经过直角锥面变形镜的校正,薄管激光光源光束质量明显改善,大气长程传输后的远场光束质量有所提高。若进一步配合常规变形镜进行联合校正,薄管激光大气长程传输后的远场光束质量可得到显著提升。Solid-state zigzag tube laser(SSZTL)is a new type of solid-state laser source with structural compactness,high gain,as well as direct transmitting.To solve the problem that the beam quality of the tube laser significantly degrades during long-distance propagation in atmosphere,the method for improving the beam quality of the tube laser based on the right-angle conical deformable mirror have been proposed.The beam correction model and the beam propagation model in atmosphere of the tube laser have been built up and the beam quality of the tube laser after long-distance propagation in atmosphere have been analyzed.Firstly,a scheme for obscuration ratio transformation of annular tube lasers have been provided,based on which the matching of the small-aperture large-obscuration-ratio tube laser and the large-aperture small-obscuration-ratio Cassegrain system have been accomplished.Then,the impacts of the beam quality of the tube laser source,the atmosphere turbulence effect and the thermal blooming effect on the propagation characteristics of SSZTLs have been numerically studied,and the mechanism of the beam quality degradation of the tube laser in the procedure of the long-distance propagation in atmosphere have been revealed.To improve the beam quality of the tube laser in far field,the right-angle conical deformable mirror have been used to correct the aberrations of the tube laser source and the phase distortions induced by the turbulence and thermal blooming effects in atmosphere.The results show that the beam quality of the laser source have been significantly improved after correction.Also,the Strehl ratio in far field have been obviously improved,especially used together with conventional deformable mirror.

关 键 词：薄管激光 直角锥面变形镜 自适应光学 遮拦比变换 大气湍流 热晕 

分 类 号：TN249[电子电信—物理电子学]