Light scattering and absorption by a radially inhomogeneous sphere: application of a hybrid numerical method

Abstract

Scattering and absorption of electromagnetic radiation by particles are important in many diverse fields, and numerical methods need to be developed to make possible the treatment of particles with arbitrary inhomogeneities, shapes, and nonlinear responses. A common difficulty in implementing numerical methods for this problem lies in the boundary condition at infinity (Sommerfeld condition). Here we show that the Sommerfeld condition can be satisfied exactly by application of the boundary-element method outside the particle. A numerical formulation of the hybrid method combining the finite-element method applied inside the particle and the boundary-element method used outside the particle is described and applied to the problem of a dielectric sphere with a radially inhomogeneous refractive index.