构建一种单层石墨烯条周期阵列结构,采用表面电流边界条件的时域有限差分法和耦合模理论对周期性阵列石墨烯条的光电特性进行研究。研究结果表明石墨烯阵列在中红外波段具有典型的表面等离子体双共振效应,周期性阵列结构可增强石墨烯表面等离子体局域场的共振效应。对石墨烯表面等离子体共振模式的谐振波长、电场能量、衰减率和寿命进行分析,仿真结果表明:当石墨烯费米能级从0.4 eV上升到0.8 eV时,可实现谐振波长从16.81 μm到11.13 μm的调谐;当石墨烯载流子迁移率从0.1 m 2·(V· s) -1变化到1.0 m 2·(V·s) -1时,可实现等离子体寿命从21 fs到223 fs的调控;当覆盖物折射率从1变化到2时,品质因数从0.14非线性地上升到0.19。该研究的方法和结论可以为石墨烯等离子体器件的设计提供参考。

In this study, we construct a periodic array of a single layer graphene ribbon based on the surface electric current boundary condition. Further, the periodic array of graphene ribbon is investigated using a finite-difference time-domain simulation and the coupled-mode theory. The results show that the graphene array exhibits a typical surface plasma double-resonance effect in the mid-infrared band. Its periodic array structure can enhance the resonance effect of graphene surface plasma local field. The resonant wavelengths, electrical field energy, attenuation rate, and lifetime of the resonance mode of graphene surface plasma are analyzed. The simulation results demonstrate that the resonance wavelength can be tuned from 16.81 to 11.13 μm when the graphene Fermi energy is increased from 0.4 to 0.8 eV and that the plasma lifetime can be regulated from 21 to 223 fs when the graphene carrier mobility is increased from 0.1 to 1.0 m ²·(V·s) ^-1. Furthermore, the quality factor increases nonlinearly from 0.14 to 0.19 when the refractive index of the superstrate is increased from 1 to 2. The research methods and conclusions of this study are useful for designing graphene plasma devices.