Proceedings PaperStructural Aspects Of Dichromatic Laser Speckle Patterns: Light Scattering From Polymer Films
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The study deals with an analysis of dichromatic speckle patterns (SP) formed in the far-field diffraction region by optically heterogeneous materials under illumination with light of two near-by wavelengths. The existence of the radial-fibrillar appearance of SP is explained; it is shown that the occurrence of the radial-fibrillar "structure" of SP cor-responds to the measurable correlation of dichromatic SP as specified by the spectral spatial cross-correlation function of the intensity fluctuations. A speckle pattern cor-relation measuring method for the determination of az (standard deviation of optical path fluctuations due to the passage of coherent light through a layer of heterogeneous material) is described, and the relations between the parameter az and the structural parameters for two simple types of heterogeneous materials are discussed. Experimental results obtained with a series of samples of polyethylene filled with CaCO3 are in a comparatively good agreement with theoretical values.