基于石墨烯纳米条波导边耦合矩形腔的等离子体诱导透明效应

为了减小器件尺寸、实现超快速响应和动态可调谐,研究了基于石墨烯纳米条波导边耦合矩形腔的单波段和双波段的等离子体诱导透明(PIT)效应,通过耦合模式理论和时域有限差分法从数值计算和模拟仿真两方面分析了模型的慢光特性.通过调节石墨烯矩形腔的化学势,同时实现了单波段、双波段PIT模型的谐振波长和透射峰值的可调谐性.当石墨烯的化学势增加时,各个波段PIT窗口的谐振波长逐渐减小,发生蓝移.此外,通过动态调谐石墨烯矩形腔的谐振波长,当石墨烯矩形腔的化学势为0.41—0.44 eV时,单PIT系统的群折射率控制在79.2—28.3之间,可调谐带宽为477 nm;当石墨烯矩形腔1, 2, 3的化学势分别为0.39—0.42 eV, 0.40—0.43 eV, 0.41—0.44 eV时,双PIT系统的群折射率控制在143.2—108.6之间.并且,整个系统的尺寸小于0.5μm~2.研究结果对于超快速、超紧凑型和动态可调谐的光传感、光滤波、慢光和光存储器件的设计和制作具有一定的参考意义.     

Dynamically tunable multiband plasmon-induced transparency effect based on graphene nanoribbon waveguide coupled with rectangle cavities system

A dynamically tunable multiband plasmon-induced transparency (PIT) effect in a series of rectangle cavities coupled with a graphene nanoribbon waveguide system is investigated theoretically and numerically by tuning the Fermi level of the graphene rectangle cavity. A single-PIT effect is realized using two different methods: one is the direct destructive interference between bright and dark modes, and the other is the indirect coupling through a graphene nanoribbon waveguide. Moreover, dual-PIT effect is obtained by three rectangle cavities side-coupled with a graphene nanoribbon waveguide. Results show that the magnitude of the dual-PIT window can be controlled between 0.21 and 0.74, and the corresponding group index is controlled between 143.2 and 108.6. Furthermore, the triple-PIT effect is achieved by the combination of bright-dark mode coupling and the cavities side-coupled with waveguide mechanism. Thus, sharp PIT windows can be formed, a high transmission is maintained between 0.51 and 0.74, and the corresponding group index is controlled between 161.4 and 115.8. Compared with previously proposed graphene-based PIT effects, the size of the introduced structure is less than 0.5 μm². Particularly, the slow light effect is crucial in the current research. Therefore, a novel approach is introduced toward the realization of optical sensors, optical filters, and slow light and light storage devices with ultra-compact, multiband, and dynamic tunable.