随着基于硅微加工技术的微机电(MEMS)技术的发展,搭建低成本的自适应光学系统以校正激光束畸变成为可能。首先根据模态耦合理论分析了热畸变对光束质量的影响,并用数值方法得到理想基模和畸变基模耦合振幅与泽尼克(Zernike)畸变之间的关系。然后采用一种新型的微机电变形反射镜搭建了一个闭环自适应光学实验系统,用来对热畸变激光光束进行补偿,并对自适应闭环控制方法进行了研究。闭环实验结果显示:闭环自适应光学实验系统能很好地改善激光束质量,斯特列尔比(Strehl Ratio)平均可以达到80%。
With the development of micro-electro-mechanical system (MEMS) based on silicon micromaching technology, it becomes possible to develop a low-cost adaptive optics system to compensate the aberration of laser beams. The effect of thermally induced aberration on laser beam quality is analyzed based on mode coupling theory. The relation between coupling amplitude of ideal and aberrated fundamental mode and Zernike aberration is numerically simulated. An adaptive optics system is presented based on a MEMS deformable micro-mirror to compensate the thermally induced aberration. From the test result, it is explicit that the adaptive system can correct the thermally induced aberration of high power lasers and increase the Strehl ratio to about 80% averagely.