Ensemble Of Nonspherical Particles Research Articles

Absorption and scattering properties of dense ensembles of nonspherical particles

The purpose of this work is to show that an appropriate multiple T-matrix formalism can be useful in performing qualitative studies of the optical properties of colloidal systems composed of nonspherical objects (despite limitations concerning nonspherical particle packing densities). In this work we have calculated the configuration averages of scattering and absorption cross sections of different clusters of dielectric particles. These clusters are characterized by their refraction index, particle shape, and filling fraction. Computations were performed with the recursive centered T-matrix algorithm (RCTMA), a previously established method for solving the multiple scattering equation of light from finite clusters of isotropic dielectric objects. Comparison of the average optical cross sections between the different systems highlights variations in the scattering and absorption properties due to the electromagnetic interactions, and we demonstrate that the magnitudes of these quantities are clearly modulated by the shape of the primary particles.

VDISORT: AN IMPROVED AND GENERALIZED DISCRETE ORDINATE METHOD FOR POLARIZED (VECTOR) RADIATIVE TRANSFER

A previously developed model for vector discrete ordinate radiative transfer in vertically inhomogeneous plane parallel media has been tested for both Rayleigh and Mie scattering phase matrices. A few errors were found in the implementation of the model that seriously impaired the model output. An improved version of the model was created in which the errors have been corrected. In addition, the procedure for computing the Fourier components of the phase matrix, required as input to the radiative transfer routines, has been replaced by a more efficient and accurate procedure. While the original version of the model was limited to phase matrices of spherical particles or to scatterers much smaller than the wavelength of the incident light (Rayleigh limit), the new version presented here is valid for a much broader range of applications including scattering by an ensemble of nonspherical particles. Extensive tests of the model in the Rayleigh limit as well as for unpolarized and polarized beam source applications in the Mie regime demonstrate the significant improvements in accuracy and efficiency achieved with the new version.

First-order multiple scattering theory for nonspherical particles

Using the vector radiative transfer equation, we have obtained the first-order solution for the problem dealing with multiple scattering from an ensemble of nonspherical particles. Representative results for low-absorbent disks (oblate spheroids) as well as high-absorbent disks were obtained. In general, it was found that multiple scattering effects were more prominent for low-absorbent particles.