| The field of plasmonics has been attracting wide interest because it has provided routes to guide and localize light at nanoscales by utilizing metals as its major building block. Meanwhile, graphene, a two-dimensional lattice of carbon atoms, has been regarded as an ideal material for electronic applications owing to its remarkably high carrier mobility and superior thermal properties. Both research fields have been growing rapidly, but quite independently. However, a closer look reveals that there are actually numerous similarities between them, and it is possible to extract useful applications from these analogies. Even more interestingly, these research fields are recently overlapping to create a new field of research, namely graphene plasmonics.;In this thesis, we present a few examples of these intertwined topics. First, we investigate "rainbow trapping" structures, broadband plasmonic slow light systems composed of single or double negative materials. We clarify the mode-conversion mechanism and the light-trapping performance by analyzing the dispersion relation. We then show that electrons in graphene exhibit photonlike dynamics including Goos- Hanchen effect and the rainbow trapping effect, but quantitatively differently. To study the dynamics of graphene electrons numerically, we develop a finite-difference time domain simulator. We also present a way to enhance electron backscattering in graphene by engineering the dispersion of electron eigenmodes in a Kronig-Penney potential. Finally, we discuss physics of graphene plasmon cavities. We report the resonant mid-infrared transmission across a plasmonic waveguide gap that is governed by the Fano interference between transmission through plasmon modes in graphene and nonresonant background transmission. An ultracompact graphene plasmon cavity, which resonates at near-infrared telecommunication frequencies, is also proposed. |
