Spiral beams analysis based on astigmatic transform

The phase retrieval algorithm for spiral beams with preset intensity distribution is demonstrated. Two-dimensional light field with like-sign phase singularities can be reduced to one-dimensional field under astigmatic transform, performed by ordinary cylindrical and spherical optics. The result field contains complete information about initial one and at the same time is more convenient for observation and registration. The following interference analysis allows to restore the quantity of singularities and their location in the low-intensity areas.