为了提高聚焦光束质量,针对高功率激光驱动器的连续相位板(CPP)进行设计,改进了传统盖斯贝格-撒克斯通(G-S)算法的设计。设计基于分步分段控制相位板频谱的目标,约束初始相位的选取,保留带有目标焦斑低频信息的初始相位信息,在迭代过程中适当控制中高频信息。实验结果表明,相对于传统随机连续初始相位,改进后CPP作用下的焦斑顶部光强方均差误差(RMS)能更快地收敛到目标阈值。改进的初始相位不仅避免了G-S算法可能产生局部最优的问题,而且也能很好地应用于非对称焦斑的设计。

We design a kind of continuous phase plate (CPP) used in high power laser driver to improve the focus beam quality. The optimal design based on controlling segmented spatial spectrum is modified from traditional G-S algorithm. The improved algorithm chooses a restrained initial phase that is related with the low frequency information of goal focal spot’s spatial spectrum, and the medium frequency and high frequency can be appropriately controlled in iterations. The experimental results show that the root mean square error (RMS) of the focal spot can quickly converge to the target threshold under the effect of improved CPP, which compared with that under the effect of the traditional random continuous initial phase. The improvement of initial phase not only can avoids the G-S algorithm easily produces local optimum value, but also the improved method has a good application for the design of asymmetric focal spot.