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Étude de la diffusion optique par des matériaux hétérogènes rugueux :
Diffusions surfacique, volumique et couplage surface/volume

Abstract : The modeling of the scattering by rough heterogeneous media is a complex subject. In our work, the size of the various element involved are in the optical and the infra-red domain. We aim this work at the computation of the Bidirectional Reflectence Distribution Function in 2D geometry. A Monte Carlo approach based on a finite difference in the temporal domain method (FDTD) for the electromagnetic computation and rough heterogeneous media generation (Metropolis) is developped.

This approach is used to study the scattering by rough surface with a gaussian or an exponential autocorrelation function. The results of these computations are compared with the ones given by the Method Of Moments. Then, a new approach to derive the effective optical constant of an heterogeneous media based on the coherent energy propagation is presented. It is used to assess the validity domain of approximate models : Maxwell-Garnett, Bruggeman, Foldy-Twersky and Keller. These results are used to study the far field scattered by a bidisperse media and the possibility of using an homogenehized media to represent the small particules. In the last part, we study rough heterogeneous media. We assess the validity of a splitting rule based on the effective optical constant previously described for the surface scattering in particular in the case where the roughness is created by the particles.
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https://tel.archives-ouvertes.fr/tel-00011577
Contributor : Hervé Chanal <>
Submitted on : Thursday, February 9, 2006 - 7:18:19 PM
Last modification on : Friday, June 26, 2020 - 2:00:03 PM
Long-term archiving on: : Saturday, April 3, 2010 - 8:26:39 PM

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  • HAL Id : tel-00011577, version 1

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Hervé Chanal. Étude de la diffusion optique par des matériaux hétérogènes rugueux :
Diffusions surfacique, volumique et couplage surface/volume. Physique Atomique [physics.atom-ph]. Ecole nationale superieure de l'aeronautique et de l'espace, 2005. Français. ⟨tel-00011577⟩

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