In this article, we investigate terahertz surface plasmons propagation in a planar waveguide comprising asymmetric resonators placed in close proximity. The waveguide is designed to support surface plasmon polaritons at two distinct terahertz frequencies, ω ₁ and ω ₂, which are near to each other. This is accomplished by carefully designing the unit cell comprising of two resonators with slightly different sizes. The resonators in the form of rectangular apertures are placed along the transverse direction in the near field regime. We observe an absorption window surrounded by two transmission resonances which are coupled to each other. As the resonators are moved apart, we observe a switching from the coupled to an uncoupled resonance state. The absorption window can be tuned by changing the resonance frequency of the resonators, which depends upon its structural parameters. We have employed a theoretical model to understand the coupling mechanism between the resonators and the dispersive behavior resulting in the absorption window. The proposed study is significant in the construction of planar terahertz components such as slow lights systems, buffers, etc, where strongly dispersive mediums play a vital role.

在本文中，我们研究了太赫兹表面等离子体激元在平面波导中的传播，该平面波导包括紧密相邻的不对称谐振器。波导被设计为支持表面等离子体激元在两个不同的频率太赫兹，ω ₁和ω ₂，彼此靠近。这是通过仔细设计包含两个尺寸略有不同的谐振器的单位单元来实现的。矩形孔形式的谐振器在近场状态下沿横向放置。我们观察到被两个相互耦合的传输共振所包围的吸收窗。当谐振器分开时，我们观察到从耦合谐振状态到非耦合谐振状态的切换。吸收窗可以通过改变谐振器的谐振频率来调整，这取决于其结构参数。我们采用了一个理论模型来理解谐振器之间的耦合机制以及导致吸收窗口的色散行为。