Power-Law/Exponential Transport of Electromagnetic Field in One-Dimensional Metallic Nanoparticle Arrays

Abstract

Based on the coupled-dipole analysis and finite-difference time-domain simulation, we have investigated the surface plasmon propagation in one-dimensional metallic nanoparticle (NP) chains. Our systematic studies reveal that the interplay between the localized plasmon excitation and the lattice collective behavior leads to two phases (I and II) of different electromagnetic (EM) field transport properties. In phase I, the EM field decays follow the power-law. In phase II, the EM field shows the exponential decay in the short-distance regime and the power-law decay in the long-distance regime. Moreover, universal power-law exponents have been found in the long propagation distance. Different EM field propagation behaviors (power-law decay with different exponents, exponential decay with different propagation length) can be transformed to each other by tuning the parameters of the excitation fields (wavelength, polarization) and/or those of the NP chains. The EM field transport mechanisms we have found are very useful in the design of plasmonic waveguide with both strong field confinement and efficient field/energy transfer, which has important applications in integrated nanophotonic circuits.