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DY: Fachverband Dynamik und Statistische Physik

DY 6: Poster Session I

DY 6.18: Poster

Montag, 22. März 2010, 16:00–18:00, Poster B2

Diffusive Transport of light in a two-dimensinal disordered packing of disks:analytical approach to transport mean free path — •Zeinab Sadjadi¹ and MirFaez Miri² — ¹Theoretische Physik, Universität des Saarlandes, 66041 Saarbrücken, Germany — ²Institute for Advanced Studies in Basic Sciences, Zanjan, 45195-1159, Iran

We study photon diffusion in a two-dimensional random packing of monodisperse disks as a simple model of granular media and wet foams. We employ ray optics to follow a light beam or photon as it is reflected by the disks. For the intensity reflectance at the disks two models are presented. In the first model the intensity reflectance of disks is assumed to be a constant r . We present an analytic theory based on persistent random walk of photons and express the transport-mean-free path l* in terms of the velocity of light in the disks and host medium, radius R and packing fraction of the disks, and the intensity reflectance. Then in a more realistic model we choose the Fresnel intensity reflectance and take into account the dependence of intensity reflectance on the incident angle of light, refractive indices if disks and host medium and other parameters. We examine our analytic results by performing numerical simulation.