Zonal control with coupling factor using an adaptive optics system at Kaeri

The correction of wavefront distortion of a laser beam is a key issue for high power laser delivery systems. For this purpose, we have developed a closed-loop adaptive optics system, which consists of a Shac-Hartmann wavefront sensor, a multichannel deformable mirror and a control computer. In this paper, the closed-loop wavefront control algorithms are discussed. The closed-loop wavefront correction was performed using a zonal control algorithm. Also, we proposed a new control algorithm using zonal control with a coupling factor. We can compensate for an arbitrary wavefront distortion of a laser beam in real time. The wavefront correction bandwidth was 5 Hz by using direct correction methods of zonal control. Although tie correction speed becomes slow in the new algorithm, the correction accuracy was more stable.