Light scattering by fractal aggregates : a Monte-Carlo method in the geometrical optics limit
نویسندگان
چکیده
2014 A numerical Monte-Carlo method is presented to study the scattering of polarized light by an assembly of identical spheres in the geometrical optics limit where the radius of the spheres is larger than the wavelength of the incident beam. In this limit both coherence effects and diffraction phenomena are not taken into account. The rays (direction and intensity) are followed during their refractions/reflections using the Snell-Descartes laws and Fresnel formulae. On each diopter, refraction, or reflection, is chosen at random and the resulting scattered intensity is corrected accordingly. The method is applied to both deterministic and random fractal aggregates of various fractal dimensions D containing up to 28 561 (deterministic) and 4 096 (random) spheres. The scattering cross-section as well as the relative intensities for various scattered angles and polarizations are systematically studied as a function of the size of the aggregates and simple scaling relations are obtained. The difference of behavior between transparent (D 2) and opaque (D > 2) aggregates is stressed. J. Phys. France 50 (1989) 1983-1994 15 JUILLET 1989, Classification Physics Abstracts 78.65S 81.35T 42.20Y
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