Radiative characteristics of fibers having non-circular cross sectional shapes

The effects of cross sectional shape of non-circular fibers on the radiative properties, such as extinction and scattering efficiencies, are numerically investigated. A finite element method is developed to solve Maxwell's equations that govern a 2-dimensional electric field induced by a single fiber that is normally irradiated by a plane wave. The angular profile of the scattered radiation as well as the scattering and extinction efficiencies are derived from the electric fields. The radiative properties of fibers with equilateral triangular cross sectional areas are compared with those of circular fibers. The results show that the intensity distribution of the scattered radiation are scarcely affected by the cross sectional shape when the size parameter is less than 2, and that the efficiencies of the triangular shaped fibers are equivalent to those of the circular fibers having the same cross sectional area. This study also shows the scattering efficiencies of fibers having rectangular cross sectional shapes become much different from those of the circular fibers as the aspect ratio of the cross section increases more than three.