OPTICAL PROPERTIES AND PLASMON RESONANCE OF COUPLED GOLD NANOSHELL ARRAYS

The optical properties and plasmon resonances coupling of ordered gold nanoshell arrays are investigated theoretically by means of finite-difference time-domain (FDTD) theory. We showed that the thickness, size and inter-shell distance of the nanoshells can tune the optical transmission of the system and the highly geometry-dependent plasmon response can be seen as an interaction between the essentially fixed-frequency plasmon response of a nanosphere and that of a nanocavity for the nanoshells. We also revealed the two different resonance modes by analyzing the spatial distributions of electric field component Ez. We proposed that the peaks of the lower energy mainly originate from the sphere plasmons coupling and the peaks of the higher energy are mainly attributed to the coupling between the sphere plasmons and the cavity plasmons.