Intraparticle surface plasmon coupling in quasi-onedimensional nanostructures

The optical properties of two-component quasi-one-dimensional nanostructures consisting of Au and Ni blocks have been investigated. The optically inactive component Ni plays a relaying role in the surface plasmon coupling both for the dipole mode and for the higher-order modes of gold blocks. The experimental results exhibit that the free electrons in Ni participate in the optical coupling phenomenon and that plasmon excitations in the Au blocks induce the free electrons in Ni to oscillate. Surface plasmons (SPs) are collective oscillations of loosely bound electrons on a metal surface resulting from an interaction with light.1 The resonance condition depends on the size, shape, composition, and dielectric constants of the metal and the surrounding medium.1–3 Metal nanoparticles display unique optical properties, and thus have stimulated intensive research in the use of SPs for a plethora of optical and biomedical applications.4–9 Among them, quasi-one-dimensional (1D) nanostructures have exhibited exceptional optical properties compared to other shaped nanoparticle