Some Characteristics of Doubly Scattered Speckle Fields

In this manuscript we investigate the space-time intensity correlation function of doubly scattered speckle, that is, the observed speckle generated by the passage of a laser light through two sequential random phase screens. It has been shown that the amplitude and intensity of the doubly scattered speckle in this case obeys a K distribution [1]. Unlike circular Gaussian speckle field, Reed’s theorem [2, 3] is not applicable for the K distributed speckle. Thus a direct derivation of the fourth-order moment is required in order to obtain a space-time intensity correla-tion function. Unfortunately, the derivation of fourth-order moment is cumbersome [4], meaning that the analytic space-time intensity correlation function for doubly scattered speckle is rarely seen. Our main goal here is to demonstrate an approach that can solve this problem.