石墨烯等离子激元的能带结构和带隙研究

Graphene plasmons have received considerable attention in recent years. Due to the existence of Dirac coves in the electronic band structures, graphene plasmons possesses some unique features that do not exist in coventional metallic surfaces. Theoretical and experimental studies show that graphene plasmons have interesting features like deep subwavelength and high localization of fields, and could have potential applications in nanophotonics and plasmonics. However, some important and fundamental questions still remain,e.g., highly efficient excitations of graphene plasmons.This is because graphene plasmons lie far below the light line,nearly impossible for their excitations by conventional methods. Another important issue is how to tailor the dispersion of graphene plasmons. In this proposal, we will tackle these important issues. We will firstly study the band structures and bandgaps of graphene plasmons and their manipulations under periodic modulations, which can be achieved by periodical changes in gate voltages, doping or putting graphene onto periodically structured dielectrics. We will also study the coupling, propagation and absorption of graphene plasmons under periodic modulations, the methods for highly efficient excitations of graphene plasmons, new phenomena resulting from special plasmon band structures and bandgaps, such as high absorption and detection in infrared and THz regimes. We try to collaborate with experimentists in order to comfirm our predictions.

最近，石墨烯中的等离子激元受到国际学术界的关注。由于石墨烯电子结构的Dirac锥特性，其支持的等离子激元表现出金属表面所没有独特的性质。石墨烯等离子激元具有深亚波长、高局域性等特性，在纳光学、等离子激元学等领域有重要的应用前景。但一些非常重要的问题还有待解决。例如，如何高效地激发石墨烯等离子激元，这是因为其色散远在光线之下，常规的光激发手段难以实现。另一重要的问题是如何调控其色散。本项目的主要研究即围绕这些基本问题。我们拟首先从理论上研究周期调制下，石墨烯等离子激元的能带结构、带隙特性以及调控机理。周期调制可以通过周期性改变栅压、掺杂或将石墨烯放在周期介质结构上等手段来实现。我们还将研究在周期调制下石墨烯等离子激元的耦合、传播及吸收特性，探索高效激发等离子激元的有效途径，基于特殊能带结构和带隙的新现象和效应，如红外和太赫兹光的超强吸收及探测等。争取与实验合作，验证理论预言。

石墨烯等离激元具有深亚波长、光场高局域性等特性，在微纳光子学、等离激元学等领域有重要的应用前景。项目围绕石墨烯等离激元的光学特性开展研究，主要研究内容有：多层石墨烯结构的光学特性，如多层石墨烯结构的光吸收、能带结构，以及石墨烯等离激元特性；介质光栅上石墨烯的等离激元能带结构，以及低能电子束脉冲导致的石墨烯等离激元激发和发射；石墨烯微纳结构中的等离激元诱导的光致透明现象；亚波长共振单元的吸收截面增大；多层石墨烯微带结构的等离激元激发和光吸收等。项目执行期间，作为通信作者在Phys. Rev. Let.、Phys. Rev. B、Opt. Express等杂志上发表SCI论文9篇，其中关于多层石墨烯光学特性的传输矩阵法的论文被它引51次，关于利用石墨烯获得太赫兹光源的论文被它引31次。圆满完成项目计划和预订目标。