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Efficient and high-quality absorption enhancement using epsilon-near-zero cylindrical nano-shells constructed by
Shiva Hayati Raad1, Mehdi Afshari-Bavil2, Dong Liu3,4
1Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, Iran.
Scientific Reports
|March 21, 2024
Summary
This study designs a compact optical absorber using graphene
Area of Science:
- Plasmonics
- Optical Metamaterials
- Nanophotonics
Background:
- Graphene's unique epsilon-near-zero (ENZ) plasmonic properties enable novel optical device designs.
- Traditional plasmonic resonances often occur at terahertz (THz)/far-infrared (FIR) frequencies.
- Controlling optical absorption requires precise manipulation of material properties and geometry.
Purpose of the Study:
- To design an efficient, compact, narrowband, and reconfigurable optical absorber.
- To leverage ENZ plasmonic resonances in graphene for enhanced absorption.
- To analyze the scattering characteristics of hollow-core plasmonic-shell cylindrical wires.
Main Methods:
- Detailed scattering analysis using Mie's theory.
- Investigation of graphene's epsilon-near-zero (ENZ) plasmonic region.
- Modeling of cylindrical elements in dense and sparse arrays.
- Analysis of polarizability and resonant scattering conditions.
Main Results:
- Achieved optical absorbers with absorption cross-sections significantly larger than geometrical and scattering cross-sections.
- Observed a blue shift in operating frequency due to ENZ plasmonic resonances.
- Demonstrated tunability of absorption rate via graphene relaxation time and chemical potential.
- Attained narrow resonance widths and a high quality factor (2272.8) in sparse arrays.
- Designed a polarization-insensitive absorber with >90% absorption across wide incident angles.
Conclusions:
- The proposed design offers an efficient and compact solution for optical absorption.
- ENZ plasmonic resonances in graphene are crucial for achieving desired operating frequencies and high absorption.
- High-quality graphene is essential for achieving high-performance resonant absorption in sparse arrays.
- The developed absorber is robust against polarization and incident angle variations.
