Modeling and Verification of Optical Mechanical Coupling for Large Aperture Optical Components Based on Flexure Back Support

In petawatt-class picosecond laser facilities, the surface figure and pointing accuracy of terminal optics directly determine the on-target focal-spot power density. For large-aperture transport mirrors arranged in compact arrays within limited space, the opto-mechanical mounting structure introduces additional deformations under clamping, attitude adjustment, and gravity loading, which can significantly degrade the system wavefront quality. To enable structural design and surface-figure feed-forward prediction, this study proposes an opto-mechanical coupled simulation framework based on Mindlin moderate-thickness plate theory, compliance relations, and surface-figure superposition. The model enables rapid prediction and optimization of figure responses under various attitudes and alignment conditions. Experiments demonstrate that the deviations between predicted and interferometrically measured PV and GRMS values are within 7.43% and 5%, respectively, with residual surface-figure RMS around 25 nm. Compared with finite-element analysis and black-box data-driven models, the proposed method achieves comparable accuracy while offering substantially higher computational efficiency, better functional extensibility, and improved interpretability of the underlying mechanical behavior.