基于荧光成像的准分子激光系统多路光束自动准直

Automatic alignment of multiplexed beams of excimer laser system based on fluorescence imaging

研究了基于准直光束成像的准分子激光主振荡功率放大(MOPA)系统的多路光束自动准直,实现了激光在放大器中的多程放大及高的靶面指向精度。采用352nm He-Cd激光作为准直光源,提出了多光束感光屏同步接收与可见光CCD荧光成像相结合的复合图像采集技术,解决了自动准直系统多路激光的近场、远场图像获取问题。利用图像区域分割处理方法编制了准直信息处理软件,实现了对多光束的自动准直闭环反馈控制。最后,结合准分子激光MOPA系统中的预放大器光学设计进行了自动准直验证实验。结果表明:准直成像光强可调谐倍数为300,成像系统在放大器窗口处固有误差占放大器口径比例小于设计值1.08%,3路激光的自动准直时间为40s,完全满足放大器的几何填充和能量提取要求。

The multiplexed beam automatic alignment of a Master Oscillator Power Amplifier（MOPA）system in a high power excimer laser based on scattering imaging was explored to achieve the multipass amplifications of amplifiers and high pointing accuracy of a target.A 325 nm He-Cd laser was selected as an automatic alignment source in the whole optical path.Then a complex imaging collection system was proposed by combining the photosensitive paper synchronized reception and a CCD visible imaging to complete the near-field and far-field scattering imaging in the automatic alignment system.Meanwhile,the information processing software was compiled based on the image region segmentation to accomplish the closed loop feedback control for automatic alignment of several array beams.Finally,image collection validation experiments for pre-amplifier beam automatic alignment were carriedout.The results indicate that the light intensity tunable multiple value of the scattering imaging system is300,the ratio of the error of automatic alignment beams on the amplifier windows and the window diameters is lower than the designed value by 1.08%and the total time of automatic alignment of the three beams is 40 s,which satisfies the demands of the amplifier for geometric fill and energy extraction.