Dynamic of speckle cluster formation

A. LENCINA; M. TEBALDI; P. VAVELIUK; N. BOLOGNINI

WAVES IN RANDOM AND COMPLEX MEDIA

Taylor and Francis

Lugar: Oxon (United Kingdom); Año: 2007 vol. 17 p. 29 - 42

1745-5030

In this work, we analyze the speckle cluster structure generated when a coherently illuminated diffuser is imaged by introducing a multiple apertures pupil mask in front of the lens plane. We demonstrate that the speckle cluster originates from the complex speckle modulation generated by multiple interferences among the wavefront passing through each aperture. The auto-correlation function of the intensity distribution when using a multiple aperture pupil arrangement is calculated. Besides, we demonstrate that the autocorrelation function and the intensity corresponding to a single scattering element in the input are coincident. This result allows interpreting the dynamics behavior of the speckle cluster formation by considering the result obtained by a single scattering element. Then, we determine the pupil mask geometrical parameters that control the cluster behavior and therefore the condition to obtain a highly repetitive cluster structure that we define as a “regular cluster”. The theoretical simulations based on the random walk model are in agreement with the experimental results supporting the validity of our approach.