Scattering of light by polydisperse, randomly oriented, finite circular cylinders
Abstract
We use the Tmatrix method, as described by Mishchenko [Appl. Opt. 32, 4652 (1993)], to compute rigorously light scattering by finite circular cylinders in random orientation. First we discuss numerical aspects of Tmatrix computations specific for finite cylinders and present results of benchmark computations for a simple cylinder model. Then we report results of extensive computations for polydisperse, randomly oriented cylinders with a refractive index of 1.53 + 0.008i, diametertolength ratios of 1/2, 1/1.4, 1, 1.4, and 2, and effective size parameters ranging from 0 to 25. These computations parallel our recent study of light scattering by polydisperse, randomly oriented spheroids and are used to compare scattering properties of the two classes of simple convex particles. Despite the significant difference in shape between the two particle types (entirely smooth surface for spheroids and sharp rectangular edges for cylinders), the comparison shows rather small differences in the integral photometric characteristics (total optical cross sections, singlescattering albedo, and asymmetry parameter of the phase function) and the phase function. The general patterns of the other elements of the scattering matrix for cylinders and aspectratioequivalent spheroids are also qualitatively similar, although noticeable quantitative differences can be found in some particular cases. In general, cylinders demonstrate much less shape dependence of the elements of the scattering matrix than do spheroids. Our computations show that, like spheroids and bispheres, cylinders with surfaceequivalent radii smaller than a wavelength can strongly depolarize backscattered light, thus suggesting that backscattering depolarization for nonspherical particles cannot be universally explained by using only geometricoptics considerations.
 Publication:

Applied Optics
 Pub Date:
 1996
 DOI:
 10.1364/AO.35.004927
 Bibcode:
 1996ApOpt..35.4927M
 Keywords:

 AEROSOL AND CLOUD EFFECTS;
 AEROSOL DETECTION;
 INSTRUMENTATION: MEASUREMENT: AND METROLOGY;
 PHYSICAL OPTICS;
 POLARIZATION;
 REMOTE SENSING;
 SCATTERING