A High-Accuracy Multidomain Legendre Pseudospectral Frequency-Domain Method With Penalty Scheme for Solving Scattering and Coupling Problems of Nano-Cylinders

A new multidomain pseudospectral frequency-domain (PSFD) method based on the Legendre polynomials with penalty scheme is developed for numerically modeling electromagnetic wave scattering problems. The primary aim of the proposed method is to more accurately analyzing scattering and coupling problems in plasmonics, in which optical waves interact with nanometer-sized metallic structures. Using light scattering by a silver circular cylinder as a first example, the formulated method is demonstrated to achieve numerical accuracy in near-field calculations on the order of 10^-9 with respect to a unity field strength of the incident wave with excellent exponentially convergent behavior in numerical accuracy. Then, scattering by a dielectric square cylinder and that by several coupled metallic structures involving circular cylinders, square cylinders, or dielectric coated cylinders are examined to provide high-accuracy coupled near-field results.