First-order speckle statistics: an analytic analysis using ABCD matrices

Within the limitations of the generalized ray-matrix method, analytical expressions for the first-order intensity moments are obtained for arbitrary cylindrically symmetric ABCD optical systems, assuming beam illumination of reflective targets with arbitrary values of surface roughness whose heights are a Gaussian process. In contrast to previous work, the results presented here are valid for an arbitrary number of correlation areas of the target that contribute to the observed intensity. Also presented here are analytic closed-form results, as well as a highly accurate approximation based on elementary functions, for the heterodyne signal-to-noise ratio in situations where the scattered light is mixed with a strong local oscillator.