OSA's Digital Library

Virtual Journal for Biomedical Optics

Virtual Journal for Biomedical Optics

| EXPLORING THE INTERFACE OF LIGHT AND BIOMEDICINE

  • Editor: Gregory W. Faris
  • Vol. 2, Iss. 8 — Aug. 10, 2007

Effective medium theories for irregular fluffy structures: aggregation of small particles

Nikolai V. Voshchinnikov, Gorden Videen, and Thomas Henning  »View Author Affiliations


Applied Optics, Vol. 46, Issue 19, pp. 4065-4072 (2007)
http://dx.doi.org/10.1364/AO.46.004065


View Full Text Article

Enhanced HTML    Acrobat PDF (657 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

The extinction efficiencies as well as the scattering properties of particles of different porosity are studied. Calculations are performed for porous pseudospheres with small size (Rayleigh) inclusions using the discrete dipole approximation. Five refractive indices of materials covering the range from 1.20 + 0.00 i to 1.75 + 0.58 i were selected. They correspond to biological particles, dirty ice, silicate, and amorphous carbon and soot in the visual part of the spectrum. We attempt to describe the optical properties of such particles using Lorenz–Mie theory and a refractive index found from some effective medium theory (EMT) assuming the particle is homogeneous. We refer to this as the effective model. It is found that the deviations are minimal when utilizing the EMT based on the Bruggeman mixing rule. Usually the deviations in the extinction factor do not exceed 5 % for particle porosity P = 0 0.9 and size parameters x porous = 2 π r s, porous / λ 25 . The deviations are larger for scattering and absorption efficiencies and smaller for particle albedo and the asymmetry parameter. Our calculations made for spheroids confirm these conclusions. Preliminary consideration shows that the effective model represents the intensity and polarization of radiation scattered by fluffy aggregates quite well. Thus the effective models of spherical and nonspherical particles can be used to significantly simplify the computations of the optical properties of aggregates containing only Rayleigh inclusions.

© 2007 Optical Society of America

OCIS Codes
(290.0290) Scattering : Scattering
(290.5850) Scattering : Scattering, particles

ToC Category:
Mass Spectrometry, Ignition, and Computational Analysis

History
Original Manuscript: October 31, 2006
Revised Manuscript: February 9, 2007
Manuscript Accepted: February 16, 2007
Published: June 12, 2007

Virtual Issues
Vol. 2, Iss. 8 Virtual Journal for Biomedical Optics

Citation
Nikolai V. Voshchinnikov, Gorden Videen, and Thomas Henning, "Effective medium theories for irregular fluffy structures: aggregation of small particles," Appl. Opt. 46, 4065-4072 (2007)
http://www.opticsinfobase.org/vjbo/abstract.cfm?URI=ao-46-19-4065


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. M. I. Mishchenko, J. Hovenier, and L. D. Travis, eds., Light Scattering by Nonspherical Particles (Academic, 2000).
  2. C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles (Wiley, 1983).
  3. P. Chýlek, G. Videen, D. J. W. Geldart, J. S. Dobbie, and H. C. W. Tso, "Effective medium approximations for heterogeneous particles," in Light Scattering by Nonspherical Particles, M.I.Mishchenko, J. Hovenier, and L. D. Travis, eds. (Academic, 2000), pp. 274-308.
  4. A. H. Sihvola, Electromagnetic Mixing Formulas and Applications (Institute of Electrical Engineers, Electromagnetic Waves Series 47, 1999).
  5. L. Kolokolova and B. Å. S. Gustafson, "Scattering by inhomogeneous particles: microwave analog experiments and comparison to effective medium theory," J. Quant. Spectrosc. Radiat. Transfer 70, 611-625 (2001). [CrossRef]
  6. N. Maron and O. Maron, "On the mixing rules for astrophysical inhomogeneous grains," Mon. Not. R. Astron. Soc. 357, 873-880 (2005). [CrossRef]
  7. B. T. Draine, "The discrete dipole approximation for light scattering by irregular targets," in Light Scattering by Nonspherical Particles, M.I.Mishchenko, J. Hovenier, and L. D. Travis, eds. (Academic, 2000), pp. 131-145.
  8. M. Min, C. Dominik, J. W. Hovenier, A. de Koter, and L. B. F. M. Waters, "The 10 μm amorphous silicate feature of fractal aggregates and compact particles with complex shapes," Astron. Astrophys. 445, 1005-1014 (2006). [CrossRef]
  9. N. V. Voshchinnikov, V. B. Il'in, and Th. Henning, "Modelling the optical properties of composite and porous interstellar grains," Astron. Astrophys. 429, 371-381 (2005). [CrossRef]
  10. B. T. Draine and P. J. Flatau, User Guide for the Discrete Dipole Approximation Code DDSCAT.6.0, astro-ph/0309069, pp. 1-46 (2003).
  11. Th. Henning and R. Stognienko, "Porous grains and polarization: the silicate features," Astron. Astrophys. 280, 609-616 (1993).
  12. K. Lumme and J. Rahola, "Light scattering by porous dust particles in the discrete-dipole approximation," Astrophys. J. 425, 653-667 (1994). [CrossRef]
  13. M. J. Wolff, G. C. Clayton, P. G. Martin, and R. E. Schulte-Ladbeck, "Modeling composite and fluffy grains: the effects of porosity," Astrophys. J. 423, 412-425 (1994). [CrossRef]
  14. A. Doicu and Th. Wriedt, "Equivalent refractive index of a sphere with multiple spherical inclusions," J. Opt. A 3, 204-209 (2001). [CrossRef]
  15. P. Mallet, C. A. Guérin, and A. Sentenac, "Maxwell-Garnett mixing rule in the presence of multiple scattering: Derivation and accuracy," Phys. Rev. B 72, 014205-014209 (2005). [CrossRef]
  16. M. Kocifaj, M. Gangl, F. Kundracík, H. Horvath, and G. Videen, "Simulation of the optical properties of single composite aerosols," J. Aerosol Sci. 37, 1683-1695 (2006). [CrossRef]
  17. Y. Guéguen, M. Le Ravalec, and L. Ricard, "Upscaling: effective medium theory, numerical methods and the fractal dream," Pure Appl. Geophys. 163, 1175-1192 (2006). [CrossRef]
  18. N. V. Voshchinnikov, "Optics of Cosmic Dust. I," Astrophys. Space Phys. Rev. 12, 1-182 (2004).
  19. Th. Henning, V. B. Il'in, N. A. Krivova, B. Michel, and N. V. Voshchinnikov, "WWW Database on Optical Constants for Astronomy," Astron. Astrophys. Suppl. sen. 136, 405-406 (1999). [CrossRef]
  20. C. Jäger, V. B. Il'in, T. Henning, H. Mutschke, D. Fabian, D. A. Semenov, and N. V. Voshchinnikov, "A database of optical constants of cosmic dust analogs," J. Quant. Spectrosc. Radiat. Transfer 79-80, 765-774 (2003). [CrossRef]
  21. H. Chang and T. T. Charalampopoulos, "Determination of the wavelength dependence of refractive indices of flame soot," Proc. R. Soc. London Sen. A 430, 577-591 (1990). [CrossRef]
  22. N. V. Voshchinnikov and V. G. Farafonov, "Optical properties of spheroidal particles," Astrophys. Space Sci. 204, 19-86 (1993). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited