High-accuracy arithmetic for cavity mirror automatic alignment in multi-pass beam system

Beam alignment of multi-pass amplification is based on cavity mirror alignment. To optimize multi-segmental parallel cavity mirror alignment arithmetic of high power solid-state lasers, propose a new type of arithmetic of multi-pass beam path cavity mirror based on diffraction symmetry, and the accuracy of multi-pass amplification beam path alignment is improved by 10μrad up to 3.96μrad. The arithmetic avoids low accuracy of CM alignment caused by poor image quality, It makes SG-Ⅲ facility operate long term and properly.