Investigation on parallel auxiliary adjusting machine of spatial filter lens for a high-power laser facility

As a key part in high-power laser facility, the spatial filter is used to determine the optical axis of the entire laser system, which consists of two conjugate lenses at both ends and filter hole in the middle. The lenses usually require precise adjustment, and the adjustment mechanism is integrated to both ends of the filter currently. To this end, a novel parallel adjusting machine for the filter lenses was proposed as an auxiliary tool in the spatial filter process. The machine was designed to realize the five-dimensional adjustment functions of the filter lenses with X-Y-Z axial translation, pitch, and yaw motion. The first-order ghost point of the filter lens was used as the feedback reference for the parallel machine to adjust Z-position of the lens. A more comprehensive optimizationoriented framework was established to improve the sensitivity of the lens to the posture error and to optimize the positioning speed based on the steepest descent method (SDM). The experimental results verified the superiority of the proposed adjustment machine and feedback reference point.