Automatic alignment of angularly multiplexed beams in excimer laser MOPA system

We present the study on multiplexed beams automatic alignment of high efficiency excimer laser. He-Cd laser with the wavelength of 325 nm is selected as the automatic alignment laser at first. And then, the crosshair arrays close to lens array are proposed and designed as the references of near-field and far-field, whereafter array beams are imaged and processed by specific fluorescence imaging system and region segmentation separately. Experiments are carried out in pre-amplifier II with three beams and double passes in excimer laser MOPA system. Results indicate that accuracy of the automatic alignment beam is 0.54% of the diameter of the windows. Meanwhile, the whole process of automatic alignment just takes 40 s, which ensures intelligent and high effective integration of automatic alignment system.