Scattering of an anisotropic sphere by an arbitrarily incident Hermite–Gaussian beam

An analytic theory for the scattering of an off-axis Hermite–Gaussian (HG) beam obliquely incident on an anisotropic sphere is developed. Based on the complex-source-point method and coordinate rotation theory, a general expansion expression for an arbitrarily incident HG beam in terms of Spherical Vector Wave Functions (SVWFs) is derived, and its convergence is numerically discussed. By introducing the Fourier transformation, the internal field expressions of the anisotropic sphere are represented. With the continuous tangential boundary conditions applied, the unknown scattering coefficients are solved. The theory and code are verified from the comparisons between the degenerated cases using our theory and those in the references. Two eigenmodes inside the uniaxial anisotropic sphere are characterized. The influences of beam mode, oblique incident angles, permittivity and permeability tensors, and sphere radius on the scattered field are analyzed numerically. The scattering intensity distributions on uniaxial anisotropic sphere in xoz and yoz plane are enantiomorphous for on-axis oblique illumination. - Highlights: • Scattering of an anisotropic sphere by an arbitrarily incident Hermite-Gaussian beam is studied. • A general expansion for an arbitrarily incident Hermite-Gaussian beam in terms of SVWFs is derived. • Effects of the beam mode, incident angles, and dielectric parameters on scattering are analyzed.