Nanowire-based enhancement of localized surface plasmon resonance for highly sensitive detection: a theoretical study

A nanowire-based localized surface plasmon resonance (LSPR) biosensor has been investigated to evaluate the impact of design parameters of nanowires on the excitation of localized surface plasmons (LSPs) and the sensitivity enhancement of a LSPR biosensor. The results based on rigorous coupled wave analysis and finite difference time domain method indicate that significant sensitivity increase is associated with LSP excitation mediated by nanowires and that resonant coupling of LSPs through a nanogroove achieves larger field enhancement and sensitivity improvement than LSP excitation in a single nanowire. A specific optimization provided a nanowire-based structure with sensitivity increase by more than 23 times as well as good linear detection properties. (c) 2006 Optical Society of America.