Zhao Chengxiang, Liu Yan, Qie Yuan, Han Fangwei, Yang Hu, Dong Haiming
Opt Express. 2019 Sep 16;27(19):26569-26578. doi: 10.1364/OE.27.026569.
Terahertz plasmon emission is the key to getting terahertz radiation, which has resulted in numerous studies on it. In this paper, we present the results of a theoretical investigation of terahertz plasmon emission by drifting electrons in a grated graphene system driven by an electric field by applying the Boltzmann's equilibrium equation method. The results show that plasmon frequencies from terahertz to infrared are generated by drifting electrons through the interaction between plasmons and electrons. Obvious increase of the plasmon emission strength with the driving electric field can be seen when the electric field is more than a certain strength (e.g. 1.0 kV/cm). The effects of electron density and the grating period on the emission strength of plasmons were also investigated. It was found that terahertz plasmons can be obtained by applying a grating with appropriate period. The plasmon frequencies can be tuned using either the driving electric field or the electron density controlled by the gate voltage or the grating parameters. This work may help to gain insight into graphene plasmonics and be pertinent to the application of graphene-based structures as electrically tunable terahertz plasmonic devices.
太赫兹等离激元发射是获得太赫兹辐射的关键，这引发了众多关于它的研究。在本文中，我们通过应用玻尔兹曼平衡方程方法，给出了在电场驱动下的光栅石墨烯系统中，漂移电子产生太赫兹等离激元发射的理论研究结果。结果表明，太赫兹到红外波段的等离激元频率是由漂移电子通过等离激元和电子之间的相互作用产生的。当电场超过一定强度（例如1.0 kV/cm）时，可以看到等离激元发射强度随驱动电场明显增加。还研究了电子密度和光栅周期对等离激元发射强度的影响。发现通过应用具有适当周期的光栅可以获得太赫兹等离激元。可以使用驱动电场或由栅极电压或光栅参数控制的电子密度来调谐等离激元频率。这项工作可能有助于深入了解石墨烯等离激元学，并与基于石墨烯的结构作为电可调太赫兹等离激元器件的应用相关。
