  Graphene plasmons are of remarkable features that make graphene plasmon
elements promising for applications to integrated photonic devices. The
fabrication of graphene plasmon components and control over plasmon propagating
are of fundamental important. Through near-field plasmon imaging, we
demonstrate controllable modifying of the reflection of graphene plasmon at
boundaries etched by ion beams. Moreover, by varying ion dose at a proper
value, nature like reflection boundary can be obtained. We also investigate the
influence of ion beam incident angle on plasmon reflection. To illustrate the
application of ion beam etching, a simple graphene wedge-shape plasmon
structure is fabricated and performs excellently, proving this technology as a
simple and efficient tool for controlling graphene plasmons.
