介绍了非稳腔薄片激光器腔内像差产生的原因及特点,提出了采用离焦校正变形镜和二维变形镜组合的方式校正腔内像差的主动校正技术,在仿真和优化设计基础上,研制的离焦校正变形镜动态范围为18.52 μm(峰谷值),二维变形镜镀膜后静态面形不大于0.04 μm(均方根误差),单驱动器动态范围大于6 μm(峰谷值),交连值在30%~35%范围内。将两种变形镜放置于激光器腔内进行主动闭环校正,经过离焦校正后光束质量改善至19.5,再经过二维变形镜校正后优化至6.5,波前像差由1.504 μm(均方根误差)减小至0.185 μm(均方根误差),光束质量提高了3倍,均方根误差值提高了8.1倍。实验结果证明,组合式校正模式可以有效地改善非稳腔薄片激光器腔内像差,其技术路线是可行的。

The causes and characteristics of the intracavity aberrations in unstable thin-disk laser are introduced. And an active correction technique is proposed to correct the aberration in the cavity by the combination of defocused and two-dimensional(2D)deformation mirrors. Based on the simulation and optimization design, the dynamic range of the defocus correction deformation mirror can reaches to 18.52 μm (peak-valley value). The static surface of the 2D mirror is less than 0.04 μm (root mean square error), the single driver dynamic range greater than 6 μm (peak-valley value), and the coupling coefficient is in the range of 30% to 35%. These two kinds of deformable mirrors are placed in the laser cavity for active closed-loop correction. The beam quality was improved to 19.5 after defocusing correction, and then improved to 6.5 after 2D deformable mirror correction. The wavefront aberration is reduced from 1.504 μm (root mean square error) to 0.185 μm (root mean square error). The beam quality increased by 3 times and the root mean square error increased by 8.1 times. Experimental results show that the combined correction mode can effectively improve the intracavity aberration in unstable thin-film laser, and its technical route is feasible.