通过对方形环孔和圆环孔形成的散斑场及其相位奇异性的研究,发现在某一平面上实部和虚部零值线的位置关系出现了复杂相切相交的情况, 复杂相切相交点也形成相位奇异, 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异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. 方形环孔和圆环孔形成的散斑场的散斑颗粒分布与传统方孔不同,受散射孔径的调制分别排成水平或竖直的条纹状轮廓和类似于圆形的轮廓,在散斑场的局部光强图中出现了很多类似于圆形的黑暗区域,称其为“光强暗核”,其中心对应着一个相位分布较均匀的涡旋.
The speckle fields and their phase singularities produced respectively by the square loop aperture and circular ring aperture are studied. It is found that the zero-contour of the real and imaginary parts occurs in the complicated tangential and intersectional situations. The tangential and intersectional points can also form phase singularities, around which the phase distribution shows the characteristics of symmetry and discontinuity,which differs from the spiral distribution around the traditional singular points formed by the zero crossings of the real and imaginary parts. The speckle particle distributions in the speckle fields produced by the square loop aperture and circular ring aperture is different from those by the traditional square aperture, and the speckle particle distributions are modulated by the scattering aperture, in stripes of horizontal or vertical outlines and circular outlines respectively. In addition, an interesting phenomenon occurs that a lot of disc-like dark regions appear in the intensity pattern of the speckle fields. We call it “light intensity dark nucleus”, whose center corresponds to a vortex with homogeneous phase distribution.