中文摘要：

通过对二维高斯相关随机表面在远场平面上产生的散斑场及其相位的计算模拟，发现在某一平面上除了实部零值线与虚部零值线有传统相交之外，还有相切和重合的情况．切点和重合线也可以形成相位奇异，并且其周围相位分布与传统的实部零值线与虚部零值线相交形成的奇点周围相位的螺旋变化不同，呈现出对称性和不连续性的特征．随着光波的传播，在不同的观察面上散斑场复振幅的实部零值线和虚部零值线的相对位置经历了由相切到重合再到相交的演变过程，相位奇异现象也随之发生变化．

英文摘要：

The two-dimensional speckle field and the phase produced by the Gaussian correlation random surfaces on the Fraunhofer plane were simulated. It was found that the zero-contour of the real and imaginary parts can be in the tangent and superposition situations besides the traditional intersection situation. The tangential points and the superposition-lines can also form phase singularities, around which the phase distribution shows the characteristics of discontinuity and symmetry and differs from the spiral distribution around the traditional singular points formed by the zero crossings of the real and imaginary parts. With the propagation of the optical wave, the relative positions of the zero-contour of the real and imaginary parts change from tangent to superposition, and then to intersection on the different observation plane with the simultaneously changes of the the phase singularities.