Dmitriev Victor, Castro Wagner
Appl Opt. 2019 Aug 20;58(24):6513-6518. doi: 10.1364/AO.58.006513.
Two novel graphene-based nonreciprocal four-port splitters for the terahertz region are proposed. The input power is divided between two output ports, whereas the input port is isolated from the output ports due to the presence of the fourth port. The splitters consist of a circular graphene resonator and four graphene waveguides coupled to the resonator. These elements are placed on the two-layer dielectric substrate. The central part of the splitter is under a biasing DC magnetic field normal to the graphene layer. The surface plasmon-polariton wave in the input port excites the dipole resonance in the resonator. The splitters have the following parameters: the input power is divided between two output ports almost equally with -4.4 dB. The input port is isolated from two output ports by -15 dB. The bandwidth is 4.0% with a central frequency of 7.4 THz. The biasing DC magnetic field is 0.8 T, and the Fermi energy of graphene ϵ=0.15 eV. Changing the Fermi energy by electrostatic gating allows one to dynamically control the central frequency of the splitters.
提出了两种用于太赫兹波段的新型基于石墨烯的非互易四端口功分器。输入功率在两个输出端口之间分配，而由于第四个端口的存在，输入端口与输出端口隔离。功分器由一个圆形石墨烯谐振器和四个与谐振器耦合的石墨烯波导组成。这些元件放置在双层介质基板上。功分器的中心部分处于垂直于石墨烯层的偏置直流磁场下。输入端口中的表面等离激元极化子波激发谐振器中的偶极子共振。功分器具有以下参数：输入功率在两个输出端口之间几乎平均分配，损耗为 -4.4 dB。输入端口与两个输出端口的隔离度为 -15 dB。带宽为 4.0%，中心频率为 7.4 THz。偏置直流磁场为 0.8 T，石墨烯的费米能 ϵ = 0.15 eV。通过静电门控改变费米能可以动态控制功分器的中心频率。
