ph0c01002_si_001.pdf (828.69 kB)
Understanding the Electromagnetic Response of Graphene/Metallic Nanostructures Hybrids of Different Dimensionality
journal contribution
posted on 2020-08-10, 17:28 authored by Tatiana G. Rappoport, Itai Epstein, Frank H. L. Koppens, Nuno M. R. PeresPlasmonic
excitations, such as surface-plasmon-polaritons (SPPs)
and graphene-plasmons (GPs), carry large momenta and are thus able
to confine electromagnetic fields to small dimensions. This property
makes them ideal platforms for subwavelength optical control and manipulation
at the nanoscale. The momenta of these plasmons are even further increased
if a scheme of metal–insulator–metal and graphene–insulator–metal
are used for SPPs and GPs, respectively. However, with such large
momenta, their far-field excitation becomes challenging. In this work,
we consider hybrids of graphene and metallic nanostructures and study
the physical mechanisms behind the interaction of far-field light
with the supported high momenta plasmon modes. While there are some
similarities in the properties of GPs and SPPs, since both are of
the plasmon-polariton type, their physical properties are also distinctly
different. For GPs we find two different physical mechanism related
to either GPs confined to isolated cavities or large area collective
grating couplers. Strikingly, we find that, although the two systems
are conceptually different, under specific conditions, they can behave
similarly. By applying the same study to SPPs, we find a different
physical behavior, which fundamentally stems from the different dispersion
relations of SPPs as compared to GPs. Furthermore, these hybrids produce
large field enhancements that can also be electrically tuned and modulated
making them the ideal candidates for a variety of plasmonic devices.