Scattering of a focused Gaussian beam by an axisymmetric particle with a nonconcentric spherical core

Abstract

Scattering of an on- or off-axis focused Gaussian beam by a dielectric spherical or a spheroidal particle with a nonconcentric spherical core is presented. The plane wave spectrum method is used to model the beam. The electric field intensities are calculated at any point using the T-matrix method, which is modified for the cases studied here. The calculated angular scattering intensities are shown for different cases of the core's offsets and for different cases of the beam-focusing positions with respect to the particle. The technique is applicable to a large-sized parameter particle with nonconcentric layers of different shapes illuminated with an arbitrarily shaped laser beam. Although the technique is applicable to a beam propagating in any direction and to an arbitrary shift of the core, all the calculations shown here are for an offset core and a beam propagating in the z-direction.