First-order speckle statistics for arbitrary aberration strength

We present a rigorous theory for the mean and standard deviation of speckle intensity for an arbitrary number of contributing phasors and an arbitrary level of phase fluctuations. This framework contains the classic models of speckle as the special cases, and it is compatible with the recently proposed models of Rician distribution of speckle intensity and of the Strehl ratio variability in adaptive optics images. We demonstrate that applicability of that or another distribution law depends not only on the level of aberrations in the pupil and the number of the phasors, but also on the observation point in the focal plane.