Investigation of composite plasmonic nanomaterial based on Au-nanoparticle/In-nanodisk array for plasmonic properties

With the rapid development of nanoscale preparation technology, multi-dimensional nanostructures have been widely used to excite new modes and generate new optical phenomena. A plasmonic nanomaterial based on nanoparticle and nanodisk array consisting of gold and indium is proposed. The reflective spectra and electric field are calculated via the finite difference time domain method, by respectively varying the gap between the nanoparticle and nanodisk, the nanoparticle radius, and the thickness of the nanodisk. The results indicate that two plasmonic resonance dips are observed in the spectra under vertical incidence, which are related to two different electromagnetic modes. It is also demonstrated that the resonance wavelength and intensity of optical nanomaterial can be effectively adjusted by structural parameters. The proposed composite structure is of great significance for applications of multi-resonance optical sensing devices.