Plasmonic Response of Nested Nanoparticles with Arbitrary Geometry

The plasmonic response of nanoshells with different geometries is calculated using effective medium theory (EMT). The cases of multishell nanospheres, spheroids, and nested nanocubes are investigated. The model is extended to include radiation and nonspherical geometries to study confocal and nonconfocal ellipsoidal nanoshells as well as the combination of nested nanospheres with nanospheroids or nanocubes. As compared with more computer-intensive methods, such as finite difference time domain method (FDTD) or discrete dipole approximation (DDA), the modified EMT gives fast and accurate results. Additionally, the model is conceptually simple allowing a direct physical interpretation of the results. This methodology is useful for experimentalists who need fast and reliable predictions of the plasmonic behavior of complex nanoparticles.