Design of a Graphene-Based Ultra-Wideband Polarization-Insensitive Absorber for Terahertz Applications

IF 4.3 4区物理与天体物理 Q2 CHEMISTRY, PHYSICAL

Plasmonics Pub Date : 2025-05-23 DOI:10.1007/s11468-025-03043-y

Subbarao Genikala, Anumoy Ghosh, Pratik Mondal, Bappadittya Roy

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引用次数: 0

Abstract

A graphene-based ultra-wideband terahertz absorber with polarization independent behavior is proposed and analyzed numerically. The proposed unit-cell structure consists of patterned graphene surface and a graphene ground plane separated by a silicon dioxide (SiO₂) layer. The simulated results exhibit that the proposed absorber structure can attain over 90% absorptivity from 0.1 to 20 THz with a fractional bandwidth of 198% while fixing the relaxation time and Fermi energy level of graphene as 0.03 ps and 1 eV, respectively. The structure gives exactly the same absorptivity response for all polarization angles rendering it completely polarization insensitive. It maintains above 80% absorptivity until 50° oblique incidence angle for both TE and TM modes. The shielding effectiveness of the proposed absorber is above 61 dB. The polarization conversion ratio of the structure is 0.12 which confirms that it does not act as a polarization converter. The absorption bandwidth can be dynamically tuned by managing the Fermi energy level and relaxation time of graphene without modifying the structure dimensions. To facilitate structure analysis, an equivalent circuit model based on transmission line theory is introduced, and the reliability of the suggested model is validated using full-wave simulation. The proposed structure is compared with similar graphene based absorbers, and it is revealed that the proposed structure has superior performance suitable for EMI/EMC and stealth applications at terahertz range.

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基于石墨烯的太赫兹应用超宽带极化不敏感吸收体的设计

提出了一种具有极化无关特性的石墨烯基超宽带太赫兹吸收体，并对其进行了数值分析。所提出的单胞结构由图案化的石墨烯表面和由二氧化硅（SiO2）层分隔的石墨烯接地面组成。模拟结果表明，当石墨烯的弛豫时间和费米能级分别为0.03 ps和1 eV时，该结构在0.1 ~ 20 THz范围内的吸光率达到90%以上，分数带宽为198%。该结构对所有偏振角都具有完全相同的吸光率响应，使其完全不敏感。在50°斜入射角下，TE和TM模式的吸收率均保持在80%以上。该吸波器的屏蔽效果在61 dB以上。该结构的极化转换率为0.12，证实了其不具有极化变换器的作用。通过控制石墨烯的费米能级和弛豫时间，可以在不改变结构尺寸的情况下动态调节吸收带宽。为了便于结构分析，引入了基于传输线理论的等效电路模型，并通过全波仿真验证了该模型的可靠性。将该结构与类似的石墨烯基吸收器进行了比较，结果表明该结构具有优越的性能，适用于太赫兹范围内的EMI/EMC和隐身应用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Plasmonics 工程技术-材料科学：综合

CiteScore

5.90

自引率

6.70%

发文量

164

审稿时长

2.1 months

期刊介绍： Plasmonics is an international forum for the publication of peer-reviewed leading-edge original articles that both advance and report our knowledge base and practice of the interactions of free-metal electrons, Plasmons. Topics covered include notable advances in the theory, Physics, and applications of surface plasmons in metals, to the rapidly emerging areas of nanotechnology, biophotonics, sensing, biochemistry and medicine. Topics, including the theory, synthesis and optical properties of noble metal nanostructures, patterned surfaces or materials, continuous or grated surfaces, devices, or wires for their multifarious applications are particularly welcome. Typical applications might include but are not limited to, surface enhanced spectroscopic properties, such as Raman scattering or fluorescence, as well developments in techniques such as surface plasmon resonance and near-field scanning optical microscopy.