In this paper, we propose a borophene-based grating structure (BBGS) to realize multi-band plasmon-induced absorption. The coupling of two resonance modes excited by upper borophene grating (UBG) and lower borophene grating (LBG) leads to plasmon-induced absorption. The coupled-mode theory (CMT) is utilized to fit the absorption spectrum. The simulated spectrum fits well with the calculated result. We found the absorption peaks exhibit a blue shift with an increase in the carrier density of borophene grating. Further, as the coupling distance D increases, the first absorption peak shows a blue shift, while the second absorption peak exhibits a red shift, leading to a smaller reflection window. Moreover, the enhancement absorption effect caused by the bottom PEC layer is also analyzed. On this basis, using a three-layer borophene grating structure, we designed a three-band perfect absorber with intensities of 99.83%, 99.45%, and 99.96% in the near-infrared region. The effect of polarization angle and relaxation time on the absorption spectra is studied in detail. Although several plasmon-induced absorption based on two-dimensional (2D) materials, such as graphene, black phosphorus, and transition metal dichalcogenides (TMDs), have been previously reported, this paper proposes a borophene-based metamaterial to achieve plasmon-induced perfect absorption since borophene has some advantages such as high surface-to-volume ratios, mechanical compliance, high carrier mobility, excellent flexibility, and long-term stability. Therefore, the proposed borophene-based metamaterial will be beneficial in the fields of multi-band perfect absorber in the near future.

中文翻译：

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基于多层硼烯带状光栅的动态可调谐多波段等离激元诱导吸收

在本文中，我们提出了一种基于硼烯的光栅结构（BBGS）来实现多波段等离子体激元诱导吸收。由上硼烯光栅（UBG）和下硼烯光栅（LBG）激发的两种共振模式的耦合导致等离子体激元诱导吸收。利用耦合模式理论（CMT）来拟合吸收光谱。模拟频谱与计算结果吻合良好。我们发现随着硼吩光栅载流子密度的增加，吸收峰呈现蓝移。此外，随着耦合距离D的增加，第一吸收峰呈现蓝移，而第二吸收峰呈现红移，导致反射窗口更小。此外，还分析了底部PEC层引起的增强吸收效应。在此基础上，采用三层硼烯光栅结构，设计了近红外区强度分别为99.83%、99.45%和99.96%的三波段完美吸收体。详细研究了偏振角和弛豫时间对吸收光谱的影响。尽管之前已经报道了几种基于二维（2D）材料的等离激元诱导吸收，例如石墨烯、黑磷和过渡金属二硫化物（TMD），但本文提出了一种基于硼烯的超材料来实现等离激元诱导的完美吸收由于硼烯具有高比表面积、机械柔顺性、高载流子迁移率、优异的柔韧性和长期稳定性等优点，因此吸收率很高。因此，所提出的基于硼烯的超材料将在不久的将来有益于多波段完美吸收体领域。