Effect of resonant localized plasmon coupling on the sensitivity enhancement of nanowire-based surface plasmon resonance biosensors

A nanowire-based surface plasmon resonance (SPR) is investigated as a structure that offers improved sensor performance. The results calculated by rigorous coupled-wave analysis on a model using a hexanedithiol self-assembled monolayer (SAM) indicate that the resonant coupling between localized surface plasmons (LSPs) of nanowires affects the sensitivity enhancement substantially, while the LSP resonance in a single nanowire also contributes. SPR characteristics change significantly by applying a SAM, which can give rise to zero sensitivity for a given SAM. The results suggest that a properly designed nanowire-based SPR biosensor can enhance sensitivity by an order of magnitude with reasonable detection properties. (c) 2006 Optical Society of America.