Wavefront control of main-amplifier system in the SG-â ¢ laser facility

SG-Ⅲ is a large, 48-beam, high power laser facility mainly for inertial confinement fusion physics experiments. Wavefront distortion is a primary factor decreasing focusability quality of laser beam and impacting secure performance of laser device, and main-amplifier system is one major source of aberrations. Based on the specific configuration of the SG-Ⅲ main amplifier, two wavefront control approaches are studied, termed as traditional four-pass wavefront correction and novel double-pass wavefront correction. Comparison results show that, both of them are feasible for the wavefront compensation, but double-pass mode is more suitable for our system, mainly because it can make the wavefront distributing more evenly in the different spatial filter pinholes, the high power laser passing through the pinholes more secure and the output beam quality meeting the required performance.