Design and simulation of terahertz perfect absorber with tunable absorption characteristic using fractal-shaped graphene layers
| Autor: | Ilangko Balasingham, Amir Maghoul, Ali Rostami, Nilojan Gnanakulasekaran |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Absorption spectroscopy Terahertz radiation perfect absorber Physics::Optics law.invention Fractal law Applied optics. Photonics Radiology Nuclear Medicine and imaging Absorption (electromagnetic radiation) Instrumentation spectral narrowing/widening Plasmon Graphene business.industry plasmonic mode Fermi energy multi-stage structure fractal graphene layer Atomic and Molecular Physics and Optics TA1501-1820 Absorption band Optoelectronics tunable business |
| Zdroj: | Photonics Volume 8 Issue 9 Photonics, Vol 8, Iss 375, p 375 (2021) |
| ISSN: | 2304-6732 |
| DOI: | 10.3390/photonics8090375 |
| Popis: | Graphene material, due to its unique conductivity and transparency properties, is utilized extensively in designing tunable terahertz perfect absorbers. This paper proposes a framework to design a tunable terahertz perfect absorber based on fractal triangle-shaped graphene layers embedded into dielectric substrates with the potential for spectral narrowing and widening of the absorption response without the need for geometric manipulation. In this way, the absorption cross-section spectra of the suggested configurations are achieved over the absorption band. First, the defection impact on the single-layer fractal triangle-shaped graphene structure inserted in insulators of the absorber is evaluated. Then, a flexible tunability of the absorbance’s peak is indicated by controlling the Fermi energy. By stacking fractal graphene sheets as a double graphene layer configuration in both the same and cross-states positioning, it is demonstrated that the absorption characteristics can be switched at 6–8 THz with a stronger amplitude, and 16–18 THz with a lower intensity. The impact of changing the Fermi potentials of embedded graphene layers is yielded, resulting in a plasmonic resonance shift and a significant broadening of the absorption bandwidth of up to five folds. Following, the absorption spectra related to the fractal triangle-shaped structures consist of a multi-stage architecture characterized by a spectral response experiencing a multiband absorbance rate and an absorption intensity of over 8 × 106 nm2 in a five-stage perfect absorber. Ultimately, the variations of the absorbance parameter and plasmonic mode under rotating the graphene sheet are explored for single and double fractal triangle-shaped perfect configurations on the absorption band. The presented mechanism demonstrates the tunability of the absorption spectrum in terms of narrowing or broadening and switching the plasmonic resonance by configuring multi-stage structures that can employ a broad range of applications for sensory devices. |
| Databáze: | OpenAIRE |
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