Speckle correlation technique as applied to structure analysis of multi-phase systems with spatially separated components

摘要

Speckle correlation diagnostics was used to study non-stationary multiple scattering multi-phase systems with spatially separated components on the instance of porous media in the course of liquid-phase evaporation. We propose a phenomenological model in which the local interfaces between air-filled and liquid-filled spaces in the probed medium act as an ensemble of the elementary dynamic scatters. The motions of local interface boundaries in such a scattering coherently illuminated system cause the dynamics of speckle patterns, and their decorrelation rate is related to mass transfer rate in the porous medium. Thus, correlation or spectral analysis of the speckle dynamics allows us to evaluate structural characteristics of such an object under given evaporation conditions. In this paper the results of experimental study of sequences of speckle images for model porous media (paper) are compared with computer simulation of irreversible growth. Possible applications of speckle correlation technique for porous media structure diagnostics in industry, biology and medicine are discussed.