Terahertz Plasmons in Periodic Structures of Epitaxial Graphene

THz surface plasmon excitation and the ultrafast-light induced plasmon dynamics have been studied in lithographically prepared nanoribbons of epitaxial graphene via combined near-and far-field THz spectroscopic probes. The measured nonlinear dynamics of plasmons are entirely controlled by the chemical potential of laser-excited hot carriers through their temperature. Indeed, the transient spectra on subpicosecond(ps) to hundred ps timescale are described by a two-temperature Drude-Lorentz model revealing the ultrafast evolution of the chemical potential.