Scattering of a Uniaxial Anisotropic Sphere Located in Dual Gaussian Beam with Arbitrary Propagation Directions

The scattering characteristics of a uniaxial anisotropic sphere illuminated by two Gaussian beams with arbitrary propagation and polarization directions are investigated. On the basis of spherical vector wave functions and coordinate rotation theory, the fields of any incident Gaussian beam with arbitrary propagation and polarization directions are expanded in terms of the spherical vector wave functions. Then the total expansion coefficients of the incident fields are derived by superposition of the vectors. Based on the Fourier transform and boundary conditions, the analytical expressions of the scattering coefficients of dual Gaussian beams with arbitrary propagation directions by a uniaxial anisotropic sphere are obtained. The effects of the incident angle, polarization angle of the dual Gaussian beams on the angle distributions of the radar cross sections (RCSs) are numerically analyzed in detail. This investigation may provide an effective test for further research on the scattering characteristic of anisotropic particles by a multiple beams and radiation forces, which are important in optical tweezers and related particle manipulation applications.