石墨烯作为一种新型二维材料，由于其具有独特的能带结构以及优异的光学、电学和力学等特性，被广泛应用于各种前沿的石墨烯等离激元光电子器件上。然而单层石墨烯对入射光的吸收率较低，与光的交互性较弱，影响所设计的石墨烯复合结构光电子器件的性能。本文正是基于上述问题，研究如何增强光与石墨烯之间的相互作用，设计出几种基于石墨烯的吸收器。

在太赫兹波段，设计了一种基于石墨烯的双窄带吸收器。通过改变每个石墨烯环的掺杂水平而不改变其几何参数，独立调节其工作频率，并利用电磁场分布揭示物理机理。鉴于优良的窄带吸收特性以及动态可调谐，将其应用于2-bit序列太赫兹识别标签模型。通过吸收光谱揭示了标签编码原理，实现2-bit序列的编码（11，10，01，00）。此外，为了打破平面层结构的约束，又设计了多层3-bit序列太赫兹识别标签结构，实现111，110，101等序列编码。

在紫外光区域，设计了一种基于石墨烯的宽带吸收器。通过对几何参数的严格优化，可以实现石墨烯紫外光域的宽带吸收。吸收率大于30%的带宽可达245 nm，相对带宽可达68%，最佳吸收峰高达54%。从电磁场分布揭示其物理机制，并分析了斜入射的角度特性。此外，为了克服极化敏感的问题，引入一种铝纳米圆盘结构。通过组合不同直径的铝纳米圆盘，利用多谐振的特点，进一步增强了石墨烯在紫外光域的宽带吸收。

以上吸收器均采用金属衬底来抑制电磁波透射，但金属的损耗会影响器件性能，同时也会增加制作成本。鉴于此，设计了一种基于石墨烯的全介质太赫兹窄带吸收器。通过将磁共振和太赫兹冷镜相结合，实现双频段太赫兹窄带吸收。经过分析计算，双谐振峰的品质因数分别高达130.88和108.25，耦合模式理论（CMT）分析的结果与仿真结果具有很高的一致性。此外，分析了几何参数和入射角对吸收谱的影响。由于石墨烯表面电导率的可调谐性，因此可以通过操纵石墨烯的化学势对制造后的器件进行光谱调节。

Graphene, as a new two-dimensional material, has been widely used in various novel plasmonic photoelectric devices due to its unique energy band structure with excellent optical, electrical and mechanical properties. However, the absorption rate of monolayer graphene for incident light is low, and the interaction with light is weak, which affects the performance of graphene-based optoelectronic devices. Based on the above problems, this paper studies how to enhance the interaction between light and graphene, and designs several graphene-based absorbers.

In the terahertz band, a graphene-based absorber is designed with two narrow bands. By changing the doping level of each graphene ring without changing its geometric parameters, its operating frequency can be adjusted independently, and the distribution of electromagnetic field is used to reveal the physical mechanism. In view of its excellent narrowband absorption characteristics and dynamic tunability, it is applied to the terahertz identification tag of 2-bit sequence. According to the absorption spectrum, the coding principle is revealed and the encoding of 2-bit sequence (11, 10, 01, 00) is realized. In addition, in order to break the restriction of planar layer structure, a multi-layer terahertz identification tag structure with 3-bit sequence is also designed to achieve coding sequence of 111, 110, 101.

In the ultraviolet region, a graphene-based broadband absorber is designed. After rigorous optimization of geometrical parameters, broadband absorption spectrum can be achieved in the ultraviolet range. The bandwidth with absorption rate above 30% can reach up to 245 nm, in which the relative bandwidth and the optimal absorption peak can reach 68% and 54%, respectively. The physical mechanism is revealed from the distribution of electromagnetic fields, and the angle characteristic of oblique incident is analyzed. Moreover, an aluminum nanodisk structure is introduced to overcome the polarization sensitivity. The absorption bandwidth of graphene in the ultraviolet domain is further enhanced by the combination of aluminum nanodisks with different diameters and the multi-resonant characteristics.

The above absorbers all adopt metal substrates to suppress the transmission of electromagnetic waves, while the loss of metal will affect the performance of the device, and also increase the fabrication cost. In view of this, a tunable dual-band all-dielectric terahertz absorber based on graphene is designed. By combining magnetic resonance and terahertz cold mirror, the narrowband absorption of dual-band can be achieved. Through analysis and calculation, the quality factors of the two resonant peaks are as high as 130.88 and 108.25, respectively. The results of the coupled mode theory (CMT) analysis are well consistent with the simulation results. Furthermore, the effects of geometrical parameters and incident angle on the absorption spectrum are analyzed. Since the surface conductivity of graphene is tunable, the manipulation of graphene chemical potential can also tune the absorption spectrum for the proposed absorber after fabrication.

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