Abstract We theoretically investigate a dynamically tunable unidirectional reflectionlessness phenomenon by applying external voltage in a graphene plasmonic waveguide system based on far-field coupling among three resonators. The system consists of three wing-shaped resonators, which are side-coupled to a graphene plasmonic ribbon waveguide. Based on the temporal coupled-mode theory (TCMT) and numerical simulation, the dual-frequency unidirectional reflectionless phenomenon is studied. The reflections for forward incidence are zero at 34.34 THz and 35.83 THz, while the reflections for backward incidence are close to 33.13% and 21.13%, respectively. The contrast ratio between the forward and backward reflections is almost 1. Besides, the non-Hermitian scattering matrix of our proposed structure is proposed to verify the existences of double exceptional points, and the tunable unidirectional reflectionless phenomenon is also achieved by changing the Fermi level of graphene.

中文翻译：

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非厄米石墨烯等离子体波导系统中的双频可调单向无反射传播

摘要 我们通过在基于三个谐振器之间远场耦合的石墨烯等离子体波导系统中施加外部电压，从理论上研究了动态可调的单向无反射现象。该系统由三个翼形谐振器组成，它们侧向耦合到石墨烯等离子体带波导。基于时间耦合模式理论（TCMT）和数值模拟，研究了双频单向无反射现象。前向入射的反射在 34.34 THz 和 35.83 THz 处为零，而后向入射的反射分别接近 33.13% 和 21.13%。前向反射和后向反射之间的对比度几乎为 1。此外，