Beam smoothing on oblique surface after focus plane

Indirect-drive Inertial Confinement Fusion(ICF) system has two requests: first, it requires incident beam to focus on a small spot with very low circular side-lobe around the edge of the hole; second, when it continue to transmit onto the wall of cavity, it requires uniform illumination. A two-step iteration algorithm aiming at two positions of this system is proposed to match these two requests with using Pure Phase Plate (PPE). Our results show that the circular side-lobe near the target hole has been depressed to about 10-11 W/cm2, and the beam has small top modulation on the target wall.