说明：  迭代傅里叶算法实现对高斯光束的整形：用malab将二维的高斯分布图形转化成三维的分布的方法和用迭代傅里叶变换（GS）的算法对高斯光束的整形做对比
(Iterative Fourier algorithm of gaussian beam shaping: the two-dimensional gaussian distribution with malab graphics into three-dimensional distribution method and using iterative Fourier transform (GS) algorithm for gaussian beam shaping do contrast)