Abstract
Based on spherical vector wave functions and their coordinate rotation theory, the field of a Gaussian beam in terms of the spherical vector wave functions in an arbitrary unparallel Cartesian coordinate system is expanded. The beam shape coefficient and its convergence property are discussed in detail. Scattering of an arbitrary direction Gaussian beam by multiple homogeneous isotropic spheres is investigated. The effects of beam waist width, sphere separation distance, sphere number, beam centre positioning, and incident angle for a Gaussian beam with two polarization modes incident on various shaped sphere clusters are numerically studied. Moreover, the scattering characteristics of two kinds of shaped red blood cells illuminated by an arbitrary direction incident Gaussian beam with two polarization modes are investigated. Our results are expected to provide useful insights into particle sizing and the measurement of the scattering characteristics of blood corpuscle particles with laser diagnostic techniques.