Understanding the Coupling Mechanism of Gold Nanostructures by Finite-Difference Time-Domain Method

Gold nanoparticle assemblies show a strong plasmonic response due to the combined effects of individual nanoparticles' plasmon modes. Increasing number nanoparticles in structured leads significant shifts optical and physical properties. We use Finite-Difference Time-Domain (FDTD) simulations analyze electromagnetic structurally ordered gold nanorods monomer dimer configurations. The coupling between monomers or dimers configurations provides unique technique for tuning spectrum intensity, spatial distribution, polarisation local electric fields within surrounding nanostructures. Our study shows an exponential behavior when two are assembled end-to-end side-by-side with small separation distance. maximum field gaps adjacent configuration describes more enhancement factor than nanorod. FDTD simulation on assembly distance up ~ 40 nm can well explain observed experimental growth dynamics nanorods.