Vector spherical wavefunctions for orthorhombic dielectric-magnetic   material with gyrotropic-like magnetoelectric properties
  Vector spherical wavefunctions were derived in closed-form to represent time-harmonic electromagnetic fields in an orthorhombic dielectric-magnetic material with gyrotropic-like magnetoelectric properties. These wavefunctions were used to formulate the T matrix for scattering by a three-dimensional object composed of the chosen material. Furthermore, a closed-form, coordinate-free expression of the dyadic Green function for the chosen material was derived. Expressions ascertained for the singularity behavior will be useful for formulating volume integral equations for scattering inside the chosen material. A bilinear expansion of the dyadic Green function was obtained in terms of the derived vector spherical wavefunctions. 
Akhlesh Lakhtakia and Tom G. Mackay
physics.optics