Boundary methods for optical nano structures

In this paper, boundary methods for solving Maxwell equations are outlined with a focus on the Multiple Multipole Program (MMP) that is very advanced and well suited when high reliability and accuracy of the results is required. After the presentation of the Generalized Point Matching (GPM) technique, that is currently the best method when matrices with high condition numbers shall be handled, different field expansions are given and applied to relatively simple structures for demonstrating the concept. Simple 2D and 3D simulations are shown as illustrations. After this, a method for the efficient handling of axi‐symmetric structures by means of ring multipoles is presented. Finally, the method is applied to a few illustrative structures that exhibit attractive features, namely plasmon resonances and optical nano jets. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)