模拟了拉盖尔高斯光束照射弱随机散射屏散射后在近场形成的光强和相位的分布，发现散射光场的光强分布图中有轮廓类似于孔雀羽毛状的光斑。这些光斑均匀分布在中心黑暗区域周围，且光斑的个数与涡旋光束的轨道角动量量子数有关，无论涡旋光束的轨道角动量量子数是整数还是分数，光斑的个数恰好是涡旋光束轨道角动量量子数的4倍。只是在分数轨道角动量量子数的光强分布图中，有一条狭缝沿水平方向将光斑均匀分裂成两瓣。该方法可用于探测涡旋光束的轨道角动量量子数。

The intensity and phase distributions of speckle fields on the near-field plane generated by the scattering of Laguerre-Gaussian beam from the weak random scattering screen are simulated. It is found that the spot profiles are similar to the peacock feather in intensity distributions of speckle fields, and those spots are uniformly distributed around the central dark spots. The number of spots is related to the orbital angular momentum quantum number of the vortex beams. The orbital angular momentum quantum number is an integer or fractional, while whether it is integer or fractional, the number spots is four times of the orbital angular momentum quantum number. In the case of fractional vortex beam, there is a spot along the horizontal direction uniformly split into two petals. This method can be used to detect the orbital angular momentum quantum number of vortex beams.