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Proceedings Paper

Validity of the diffusion approximation for the description of a short pulse diffusely reflected from a resonant random medium
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Paper Abstract

A recently derived radiative transfer equation with three Lorentzian kernels of delay is applied to an albedo problem on a scalar wave field quasi-monochromatic pulse diffuse reflection from a semi-infinite random medium consisting of resonant point-like scatterers. The albedo problem is solved exactly in terms of the Chandrasekhar consisting of resonant point-like scatterers. The albedo problem is solved exactly in terms of the Chandrasekhar H-function, extended analytically into the single scattering complex albedo (lambda) -plane. Simple analytical asymptotics for the non- stationary scattering function is obtained in the limit related to large values of the time variable. The exact analytic solution for the time-evolution of a diffusely reflected short pulse is used to analyze an accuracy of the non-stationary scattering function calculated in the diffusion approximation. It is shown that the diffusion asymptotics describes the exact solution with a relative error not exceeding one percent only at larger values of dimensionless wave propagation time t equals t/to > 200 where to stands for a mean free time of wave radiation between scattering events defined in terms of the wave phase in a random medium consisting of point-like scatterers tuned to the Mie resonance. Besides, the accuracy of the diffusion asymptotics falls off providing that wave scattering approaches the resonance conditions.

Paper Details

Date Published: 13 October 1998
PDF: 10 pages
Proc. SPIE 3467, Far- and Near-Field Optics: Physics and Information Processing, (13 October 1998); doi: 10.1117/12.326816
Show Author Affiliations
Mikhail Yu. Barabanenkov, Institute of Microelectronics Technology and High Purity Materials (Russia)
Vitalii V. Aristov, Institute of Microelectronics Technology and High Purity Materials (Russia)


Published in SPIE Proceedings Vol. 3467:
Far- and Near-Field Optics: Physics and Information Processing
Suganda Jutamulia; Toshimitsu Asakura, Editor(s)

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