Additional Absorption in the Strongly Scattering Absorbing Media

Vasil P. Yashchuk 1Eugen O. Tikhonov 3Olga A. Prygodjuk 1Volodymyr I. Bezrodny 3M. V. Zhuravsky 1Olga V. Levandovska 1Yury D. Filatov 2

1. Department of Physics, Taras Shevchenko Kyiv University, 6 Gloushkov avenue, Kyiv 252022, Ukraine
2. V.Bakul Institute for Superhard Materials, NAS, 2 Avtozavodskaya, Kyiv 254074, Ukraine
3. Institute of Physics, National Academy of Sciences, Prospekt Nauki 46, Kyiv 03650, Ukraine

Abstract

The strongly scattering colored and luminescence media are interested as coating with specific color characteristics and as active media of random lasers. Multiple scattering significantly influences the optical properties of the media. This work is devoted to simulation of the process of light propagation through the scattering medium under singular and multiple scattering regimes. The scattering medium is simulated by Monte-Carlo method as randomly located spherical particles dipped into the homogeneous substance. The interaction between light and particles is assumed to accord to geometrical optics that is applicable when particle size is larger than light wavelength.
The beam attenuation coefficient kΣ was calculated versus the scattering particle concentration Cp and absorption coefficient of the interparticle substance ka. The attenuation coefficient kΣ monotonically grows with the Cp increasing. But it is essentially that kΣ undergoes sharp change at certain particle concentration range when the absorbing interparticle substance is used. The change is sharpening with ka increasing and is absent in the case of the non-absorbing substance ka=0.
The sudden change was shown to appear at the particle concentration of single-to- multiple scattering regime transition. Out of the transition region the kΣ (Cp) is a stepless function. The sudden change of the kΣ (Cp) dependence is explained with additional absorption. It appears due to light path lengthening under the multiple scattering regime. The calculated dependencies are in good correlation with experimental results.

 

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Presentation: oral at E-MRS Fall Meeting 2004, Symposium G, by Vasil P. Yashchuk
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-04-30 17:02
Revised:   2009-06-08 12:55