Numerical investigation of light scattering by coupled plasmonic nanospheres using a high-accuracy multidomain Legendre pseudospectral time-domain method

A high-numerical-accuracy multidomain Legendre pseudospectral time-domain (PSTD) method is utilized to study the three-dimensional problem of light scattering by coupled metallic nanospheres and associated plasmonic resonances. With the multidomain technique, the simulation environment is partitioned into curvilinear hexahedral subdomains that well match the geometrical profile and material interfaces, which is an essential treatment to assure numerical accuracy, in particular, in near-field calculations. Cross sections are accurately calculated for studying the effects of different sphere radii and spacings. Interactions between two silver spheres are investigated for different incident wave propagation directions and polarizations. Electric near fields at plasmon resonances are examined.