Gap plasmonic effects of gold nanoparticles on metallic film

The effective confinement of light in a deep-subwavelength volume can be achieved in metallic nanostructures through the electronic resonance, surface plasmons (SPs). There are few ways to enhance the localization of the field such as adopting metallic nanopost or nanowire structures on the precious metallic film. The achieved highly enhanced field localization through SPs can be exploited for surface-enhanced spectroscopy, biosensor, enhancing energy emitter, and enhanced energy generator. Also, many researches have been tried with few-nanometer gap between the metals for achieving large field enhancements. In this paper, by comparing the scattering of gold nanoparticles, the effects of metallic film of substrates were investigated through simulation. In addition, as changing of the gap between gold nanoparticle and metallic surface, different resonance wavelengths were observed in scattering spectra from simulation and practical experiments. We confirmed that the gold film with gold nanoparticles shows the most distinctive scattering spectra. The numerical demonstration was matched with our experimental demonstration, also with the previously introduced papers as well.