Convergence of the iterative T-matrix method

Among the various methods for computing the T-matrix in electromagnetic and acoustic scattering problems is an iterative approach that has been shown to be particularly suited for particles with small-scale surface roughness. This method is based on an implicit T-matrix equation. However, the convergence properties of this method are not well understood. Here, a sufficient condition for the convergence of the iterative T-matrix algorithm is derived by applying the Banach fixed point theorem. The usefulness of the criterion is illustrated by applying it to predicting, as well as to systematically improving the convergence of the iterative method. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen