Xu Zenghui, Wu Dong, Liu Yumin, Liu Chang, Yu Zhongyuan, Yu Li, Ye Han
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Post and Telecommunications, Beijing, 100876, China.
School of Science, Beijing University of Post and Telecommunications, Beijing, 100876, China.
Nanoscale Res Lett. 2018 May 9;13(1):143. doi: 10.1186/s11671-018-2552-z.
We propose and numerically demonstrate an ultra-broadband graphene-based metamaterial absorber, which consists of multi-layer graphene/dielectric on the SiO layer supported by a metal substrate. The simulated result shows that the proposed absorber can achieve a near-perfect absorption above 90% with a bandwidth of 4.8 Thz. Owing to the flexible tunability of graphene sheet, the state of the absorber can be switched from on (absorption > 90%) to off (reflection > 90%) in the frequencies range of 3-7.8 Thz by controlling the Fermi energy of graphene. Moreover, the absorber is insensitive to the incident angles. The broadband absorption can be maintained over 90% up to 50°. Importantly, the design is scalable to develop broader tunable terahertz absorbers by adding more graphene layers which may have wide applications in imaging, sensors, photodetectors, and modulators.
我们提出并通过数值模拟演示了一种基于石墨烯的超宽带超材料吸收器，它由多层石墨烯/电介质组成，位于由金属衬底支撑的SiO层上。模拟结果表明，所提出的吸收器在4.8太赫兹的带宽内可实现高于90%的近乎完美吸收。由于石墨烯片的灵活可调性，通过控制石墨烯的费米能量，吸收器的状态可以在3 - 7.8太赫兹的频率范围内从开启状态（吸收率>90%）切换到关闭状态（反射率>90%）。此外，该吸收器对入射角不敏感。在高达50°的入射角下，宽带吸收可保持在90%以上。重要的是，通过添加更多的石墨烯层，该设计可扩展以开发更宽的可调太赫兹吸收器，这在成像、传感器、光电探测器和调制器等方面可能有广泛应用。
