提出一种适用于连续相位板设计的改进Gerchberg-Saxton(GS)算法,该算法应用相位展开相关原理,结合滤波处理使GS算法设计的近场相位连续分布,同时提出在GS算法的远场迭代中采用经过修正的振幅函数,可使远场光斑的包络更接近目标函数。模拟实验表明,该方法解决了现有连续相位板设计中相位连续性与靶面光强控制效果难以同时优化的矛盾,可满足惯性约速聚变(ICF)对束匀滑元件相位连续性、光斑包络及能量集中度的要求。

An improved Gerchberg-Saxton (GS) algorithm for constructing fully continuous phase plate for beam shaping is proposed. The continuity of the phase plate can be ensured by use of phase unwrapping algorithm and Fourier filter operation,and a better far-field intensity profile can be obtained when the objective amplitude is replaced with a proper modified amplitude function during iteration. The simulation test proves that the method has resolved the conflict between the demand of the phase continuity in the phase plate designing and the optimization of the target beam intensity profile. The demand of the distribution continuity for beam smoothing element,good profile of the target beam and high energy centrality in inertial confinement fusion can be satisfied simultaneously by this algorithm.