  With the unique possibilities for controlling light in nanoscale devices,
graphene plasmonics has opened new perspectives to the nanophotonics community
with potential applications in metamaterials, modulators, photodetectors, and
sensors. This paper briefly reviews the recent exciting progress in graphene
plasmonics. We begin with a general description for optical properties of
graphene, particularly focusing on the dispersion of graphene-plasmon
polaritons. The dispersion relation of graphene-plasmon polaritons of spatially
extended graphene is expressed in terms of the local response limit with
intraband contribution. With this theoretical foundation of graphene-plasmon
polaritons, we then discuss recent exciting progress, paying specific attention
to the following topics: excitation of graphene plasmon polaritons,
electron-phonon interactions in graphene on polar substrates, and tunable
graphene plasmonics with applications in modulators and sensors. Finally, we
seek to address some of the apparent challenges and promising perspectives of
graphene plasmonics.
