Abstract

We show that the use of a matrix inversion scheme based on a special lower triangular–upper triangular factorization rather than on the standard Gaussian elimination significantly improves the numerical stability of T-matrix computations for nonabsorbing and weakly absorbing nonspherical particles. As a result, the maximum convergent size parameter for particles with small or zero absorption can increase by a factor of several and can exceed 100. We describe an improved scheme for evaluating Clebsch–Gordon coefficients with large quantum numbers, which allowed us to extend the analytical orientational averaging method developed by Mishchenko [J. Opt. Soc. Am. A 8, 871 (1991)] to larger size parameters. Comparisons of T-matrix and geometrical optics computations for large, randomly oriented spheroids and finite circular cylinders show that the applicability range of the ray-tracing approximation depends on the imaginary part of the refractive index and is different for different elements of the scattering matrix.

© 1997 Optical Society of America

Integral light-scattering and absorption characteristics of large, nonspherical particles

Alexander A. Kokhanovsky and Andreas Macke
Appl. Opt. 36(33) 8785-8790 (1997)

Scattering of light by polydisperse, randomly oriented, finite circular cylinders

Michael I. Mishchenko, Larry D. Travis, and Andreas Macke
Appl. Opt. 35(24) 4927-4940 (1996)

Light scattering by polydispersions of randomly oriented spheroids with sizes comparable to wavelengths of observation

Michael I. Mishchenko and Larry D. Travis
Appl. Opt. 33(30) 7206-7225 (1994)

Light scattering by size–shape distributions of randomly oriented axially symmetric particles of a size comparable to a wavelength

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Appl. Opt. 32(24) 4652-4666 (1993)

Scattering of electromagnetic waves by spheroidal particles: a novel approach exploiting the T matrix computed in spheroidal coordinates

F. Michael Schulz, Knut Stamnes, and Jakob J. Stamnes
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