Candidate: Bogdan Danila

Degree of: Doctor of Philosophy

Department: Physics

Title: Phase Coherent Effects in the Speckle Correlation of Light Scattered from Volume Disordered Media and Randomly Rough Surfaces

Committee: Dr. Arthur McGurn, Chair
Dr. Paul Pancella
Dr. Sung Chung
Dr. Alvin Rosenthal
Dr. Hossein Mousavinezhad

Date: Friday, October 8, 2004 3:00 p.m.-5:00 p.m.
2202 Everett Tower, Bradley Commons

Abstract: We present a study of the statistics of the intensity patterns produced when coherent light is scattered by random media (volume disorder) or randomly rough surfaces. Such a random, granular interference pattern is called speckle. Particular emphasis is on the statistical correlations arising between the fluctuations of the intensities corresponding to distinct scattering paths, which are quantified by the speckle correlation function. In the first part, we present results for the correlation function computed for volume-disordered media by means of numerical simulation. Our focus is on the sensitivity of the correlation function to statistical parameters characterizing the volume distribution of the refraction index. In the second part, we present theoretical calculations of the scattering cross section and speckle correlation function in the case of light scattered by randomly rough dielectric surfaces. Our studies are based on a rough surface model consisting of a plane vacuum-dielectric interface upon which Gaussian shaped, parallel ridges made from different dielectric materials are placed at random. We show that the dielectric resonance of the ridge material can be used to enhance weak localization phenomena leading to important features in the correlation function. In addition, we present results for surfaces with randomly shaped ridges as well as for surfaces with identical ridges made at random from two different materials.

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