A dual-frequency absorber with periodic double-layer graphene ring arrays separated by dielectric spacer is proposed. Coupled-mode theory and finite difference time domain method are used to analyze the perfect absorption and the absorption mechanism. Moreover, the influences of structural parameters and chemical potential of graphene on the peak positions have been investigated. Benefiting from chemical potential can be controlled by external bias voltage, thus the proposed structure can be used as a dynamically tunable absorber. Such simple absorber has potential applications in optical storage devices and frequency-selective detectors for terahertz regime.

中文翻译：

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基于石墨烯环的动态可调双频太赫兹吸收器

提出了一种双频吸收器，其具有由介电间隔物分隔的周期性双层石墨烯环阵列。采用耦合模式理论和时域有限差分法分析了完美吸收和吸收机制。此外，还研究了石墨烯的结构参数和化学势对峰位置的影响。受益于化学势可以通过外部偏置电压控制，因此所提出的结构可以用作动态可调吸收器。这种简单的吸收器在光存储设备和太赫兹范围的频率选择探测器中具有潜在的应用。