Experimental studies on the statistical functions of speckle fields based on the extraction of the complex amplitudes by use of interference beam

Abstract

Using the interference patterns of speckle fields and the reference beam, we extract digitally the complex amplitudes, phases and intensities of speckles fields and then study experimentally their properties. The influences of noise on the measurement of statistical functions, especially on that of the probability density function, appearing in the conventional method is satisfactorily eliminated. The experimental studies of the statistical properties of the complex amplitude and the phases of the speckle fields were also performed. By the practical measurement of speckle fields scattered at different angles, we find that the speckles are laterally broadened gradually with increase of the scattering angle, and their average widths become anisotropic. Such anisotropy brings about no change in the probability density function of the speckle fields, which remain circularly Gaussian as in the case of the traditional small angle scattering.