Graphene Plasmonics For Near-field And Far-field Mid-infrared Light Manipulations

Graphene is one kind of two-dimensional materials,and it is an advantaged surface-plasmon supporter in the terahertz to mid-infrared frequency range.The extreme con-finement and electrical tunability of graphene plasmons are promising in near-field and far-field mid-infrared light manipulations.Here we investigate light manipulations based on graphene plamsons,and the works incude:1.The realization of tailorable reflection of graphene plasmons based on ion-induced defect boundary.Depending on ion dose,the reflection intensity and plamson damping near the boundary can be manipulated.Moreover,a qualitative model is presented to explain the experimental results.2.Near-field properties of ion-induced graphene disks are investigated.Defects near the structure edge weaken the response intensity of edge modes,but meanwhile pro-vide electrical connectivity to the isolated disks.Accordingly,near-field response of the disk is electrically tuned under a back-gate configuration for the first time.More-over,graphene noncentric rings with near-field confinement range of 2×10^-4λ₀²are demonstrated,where the quadrupole plasmon modes are excited.3.An unqiue plasmon-induced transparency system with near-field coupling distance larger than 100 nm in mid-infrared is investigated.The origin of the transparency window in spectrum is analyzed objectively.The proposed system is easy-fabricated,and exhibits flexible tunability in slow-light and electro-optical switches,promising for practical active photonic devices.