基于石墨烯表面等离激元的红外光场调控研究

Surface plasmons in 2-D material - doped graphene possess more advantages than in tranditional 3-D materials- noble metal. Specifically, not only the electromagnetic fields in infrared range of graphene plasmons are more localized, but also propagating losses are lower than metallic plasmons. More importantly, the actively control of graphene plasmons is much more convenient than metallic plasmons. In this project, we try to actively control the interaction between graphene with fast electron beams and infrared light, which is based on the property that the density of carriers of graphene can be conveniently tuned by gating voltages or chemical doping. Based on this principle, the localization and propagation of graphene plasmons are also investigated. In further, the physical mechanism for highly integrated graphene based optical devices such switches, waveguides will also be studied.

二维材料掺杂石墨烯中存在的元激发-石墨烯表面等离激元在红外光场局域、低损耗传播以及主动调控方面相对于传统三维贵金属材料（如金、银等）表面等离激元都具有更大的优势。在本项目中，我们将基于掺杂石墨烯表面等离激元的性质，引入栅电压和化学掺杂的方式来改变掺杂石墨烯的自由载流子浓度，从而调控掺杂石墨烯的二维电导率以及费米能级，从而实现掺杂石墨烯与快电子束和红外光的相互作用的控制，实现红外光近场及远场，即局域和传输的的调控，并基于此开展集成的光开关、光波导等应用器件的物理机理的研究。

与贵金属表面等离激元相比，中红外石墨烯等离激元具有更强的光场局域能力，并且更易于通过电场等方式来动态调控。在本项目中，我们研究了中红外石墨烯等离激元的单向激发、传播、耦合，调控以及近场探测等，进一步提出实现石墨烯等离激元带阻滤波器的方案。具体，我们研究了利用金属天线以及近场相干效应来实现石墨烯等离激元的单向激发、构造非平面内的石墨烯波导实现中红外等离激元的高效传输、通过扩展石墨烯与石墨烯光栅耦合实现等离激元诱导透明效应、利用单轴应力调控偶极子与石墨烯等离激元的耦合、通过离子束诱导人工石墨烯缺陷实现对石墨烯等离激元反射的调控、通过离子束构造二维石墨烯纳米结构，实现其近场的极端聚焦以及背栅调控。相关的研究工作极大的拓展了石墨烯等离激元效应的研究，为利用石墨烯等离激元效应的中红外集成光子器件的实现提供了很好的基础。