Investigation of Nonlocal Effects On Metal Dimers

In this paper, the interaction of light with coupled metalic nanoparticles by different models are studied. To investigate nonlocal effects simple suggested model and hydrodynamical model are utilized. Metalic nanoparticles are simulated, by taking account nonlocal effects in simple model. Therefore metal is replaced by a thin composite layer on metal-dielectric interface. The simulation is done by finite element method. The extinction-cross section spectra of the desired structure comparison is calculated by local, nonlocal and simple model. Nonlocal models have blueshift regarding local model, for desired structure the blueshift of the first peak in the extinction cross section spectra is 0.19 eV. The extinction-cross section spectra of various separation distance of nanoparticles are shown. Furthermore, the influence of increasing nanoparticles radius on extinction-cross section is analyzed in details. The results reveal that by reducing nanoparticles radius or gap, surface plasmon peaks are increased, due to the stronger nonlocal response. In smaller radius, the blueshift is significantly larger by nonlocal model relative to local model.