Perturbation theory for scattering from dielectric spheroids and short cylinders

Abstract

The perturbation theory suggested by Shifrin is applied through the second order to the scattering of light from dielectric spheroids and finite cylinders. In the case of short dielectric cylinders, this technique provides an accurate prediction of the scattering pattern in its range of applicability, and this prediction is especially useful as no exact scattering solution exists. The validity of the perturbation theory is established by comparison with exact results for the spheroid, and excellent agreement is shown for ka(m − 1) ≈ 1, where k = 2π/λ, a is a representative target dimension, and m is the index of refraction. The results for the finite cylinder are refined from our previous work by a careful construction of the internal electrostatic solution. This allows the calculation of intensities for short cylinders. Comparisons are made between the spheroids and cylinders of equal volumes for aspect ratios ranging from ½ to 5, and significant differences are noted in some cases.