Scattering Of Gaussian Beams By Multilayered Spheroidal Particle

This thesis in theory deals with electromagnetic wave scattering by multilayeredconfocal and non-confocal spheroidal particles illuminated by Gaussian beams, in which themain contributions are as follows:1. In the case of multilayered confocal spheroidal particles, the scattered fields as well as the fields within each layer are obtained in terms of infinite series with spheroidal vector wave functions by using an appropriate expansion of the incident Gaussian beam. By virtue of the boundary conditions, we write the set of equations for determining the unknown expansion coefficients and then solve it. From all these discussions, the scattered fields and normalized scattering cross sections are computed.2. We present a solution to the scattering of Gaussian beams by a concentric multilayered non-confocal spheroidal particle by taking a concentric two-layered one as an example. Because the boundaries of these two layers are connected with two different spheroidal coordinate systems, firstly, the electromagnetic fields between the inner and outer boundaries are expanded in terms of the spheroidal vector wave functions with reference to these two systems, and the electromagnetic fields within the inner boundary with reference to the system for it. Secondly, the electromagnetic fields between the inner and outer boundaries are expressed in terms of infinite series with spherical vector wave functions using the relations between the spheroidal vector wave functions and spherical ones. By applying the boundary conditions and the orthogonality of spherical vector wave functions, an adequate number of relations between the unknown coefficients is generated. From all these discussions, the scattered fields and normalized scattering cross sections are computed. As far as we know, such a method has not been presented in the literature.