Far-field and near-field monitoring of hybridized optical modes from Au nanoprisms suspended on a graphene/Si nanopillar array.

The optical hybridization of localized surface plasmons and photonic modes of dielectric nanostructures provides us wide arenas of opportunities for designing tunable nanophotonics with excellent spectral selectivity, signal enhancement, and light harvesting for many optical applications. Graphene-supported Au nanoprisms on a periodic Si nanopillar array will be an ideal model system for examining such an optical hybridization effect between plasmonic modes and photonic modes. Here, through the measurement of the reflectance spectra as well as graphene phonons by surface-enhanced Raman scattering (SERS), we investigated both the far-field and near-field properties of these optically hybridized modes.

Effects of the rotation angle on surface plasmon coupling of nanoprisms.

We studied the effects of relative orientation of bowtie nanostructures on the plasmon resonance both experimentally and theoretically in this work. Specifically, we fabricated gold bowtie nanoantennas with rotated nanoprisms, measured the near-field and the far-field resonance behaviors using Raman spectroscopy and scattering microspectroscopy, and simulated the effects of the rotation angle on the localized surface plasmonic resonance using finite-difference time-domain simulations. In addition to the widely-discussed dipolar resonance in regular bowtie nanostructures, defined as tip-mode resonance in the present study, the excitations of edge-mode resonance were discovered under certain rotation angles of nanoprisms.