MULTIDIPOLE FORMULATION OF THE COUPLED DIPOLE METHOD FOR ELECTROMAGNETIC SCATTERING BY AN ARBITRARY PARTICLE

We present an improved formulation for low-frequency light scattering by an arbitrarily shaped particle, using a multiple-scattering development of a modified coupled dipole method. In this formulation the volume of a particle is discretized as an array of different types of dipolar subunit located on the sites of a cubic lattice. The main advantage of the formulation is to reduce the number of dipolar subunits and to obtain a better approximation of particle geometry than with the standard method that uses one type of dipole. Calculations performed for spherical, coated spherical, and cubic particles require less computing time and show good agreement with respect to a uniform discretization.