Liu Yan, Zhong Renbin, Huang Jiebiao, Lv Yilin, Han Chen, Liu Shenggang
Opt Express. 2019 Mar 4;27(5):7393-7404. doi: 10.1364/OE.27.007393.
Dynamically and independently tunable absorbers based on multilayer metal-graphene metamaterials are proposed to achieve multi-band and ultra-wide-band absorbing properties at mid-infrared frequencies. Dual-band, triple-band and even more bands absorption can be arbitrarily customized by etching the appropriate number of tandem gold strips in each meta-molecule, as well as stacking multiple metal-graphene layers. Through tuning the Fermi energy level of the graphene in each metal-graphene layer separately, the multiple absorption resonances can be dynamically and independently adjusted. With side-by-side arrangement of the gold strips in each supercell, the proposed structure is rendered to be a promising candidate for ultra-wide-band absorber. The extreme bandwidth exceeding 80% absorption up to 7.5THz can be achieved with a dual-layered structure, and the average peak absorption is 88.5% in the wide-band range for lossless insulating interlayer. For a triple-layered structure, the average peak absorption is 84.7% from 27.5 THz to 38.4 THz with a minimum of 60%. The absorption windows can be even further broadened with more metal-graphene layers. All these results will benefit the integrated microstructure research with simple structure and flexible tunability, and the multilayer structure has potential applications in information processing fields such as filtering, sensing, cloaking objects and other multispectral devices.
提出了基于多层金属-石墨烯超材料的动态独立可调谐吸收器，以在中红外频率实现多波段和超宽带吸收特性。通过蚀刻每个超分子中适当数量的串联金条以及堆叠多个金属-石墨烯层，可以任意定制双波段、三波段甚至更多波段的吸收。通过分别调节每个金属-石墨烯层中石墨烯的费米能级，可以动态独立地调节多个吸收共振。通过在每个超胞中并排排列金条，所提出的结构成为超宽带吸收器的有希望的候选者。双层结构可以实现高达7.5太赫兹的超过80%吸收的极端带宽，对于无损绝缘中间层，在宽带范围内平均峰值吸收为88.5%。对于三层结构，在27.5太赫兹至38.4太赫兹范围内平均峰值吸收为84.7%，最小值为60%。随着更多金属-石墨烯层的增加，吸收窗口可以进一步拓宽。所有这些结果将有利于具有简单结构和灵活可调性的集成微结构研究，并且多层结构在诸如滤波、传感、物体隐身和其他多光谱器件等信息处理领域具有潜在应用。
