Using a technique based on Mie theory, we calculate the scattering intensity of light from particles of arbitrary size that differ slightly from spherical shape. The boundary conditions are approximated linearly in the deviations <i>r</i> from a spherical shape, which are expanded in spherical harmonics. The validity of the approach is restricted to <i>r</i> ≪ R<sub>o</sub> and <i>r</i> ≪ λ/2π, <i>R</i><sub>o</sub>. and λ being the radius of the sphere and the wavelength of the light in the outer medium, respectively. The scattering cross section is calculated for a liquid drop fluctuating around the spherical equilibrium shape and for rigid nonspherical homogeneous bodies with specific and random orientation with respect to the scattering geometry. We find that only moments of the deviations in the range 2 ≤ <i>l</i> ≤ 4π<i>R</i><sub>o</sub>/λ contribute to the scattering. Only those moments with azimuthal symmetry with respect to the ingoing wave vector contribute to the scattering. For small spheres, 3 the depolarization ratio is significantly influenced by ellipsoidal deviations.
© 1982 Optical Society of America
Michael Elwenspoek, "Theory of light scattering from aspherical particles of arbitrary size," J. Opt. Soc. Am. 72, 747-755 (1982)