A method of aberration measurement and correction for entire ICF beam path

In an inertial confinement fusion (ICF) system, wave-front aberrations existed in laser beam will enlarge the focal spot size and decrease power density at the target. Fortunately, an adaptive optical system (AO) could be employed in ICF system to correct the beam aberrations. As a powerful wave-front detector, Hartmann-Shack (H-S) sensor is often utilized as a wave-front sensor in AO. However, H-S sensor can not detect the aberrations after the sampling location. A new method is presented to measure the aberrations of entire ICF beam path in this paper. Based on the AO, a CCD is installed in the target chamber to detect the focal spot distribution. The deformable mirror's (DM) is yielded to different surface shapes; the extra different aberrations are modulated and added to ICF beam path, and then create their corresponding focal spots. The extra aberrations and the corresponding focal spots intensity could be recorded simultaneously by H-S sensor and CCD respectively. An amendatory phase-retrieval algorithm which is introduced can reconstruct the aberrations of entire ICF beam path from the pairs of extra aberrations and their corresponding focal spots intensity. The numerical simulation show that the AO can correct the aberrations of entire beam path of ICF successfully based on this method.