Numerical Study of Angle-Insensitive and Tunable Dual-Band THz Absorber Using Periodic Cross-Shaped Graphene Arrays

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Terahertz (THz) absorbers are crucial for various applications, including sensing and imaging.
• Graphene's unique electronic properties offer potential for novel THz absorption devices.
• Achieving dual-band absorption with precise control remains a challenge.

Purpose of the Study:

• To design and demonstrate a dual-band terahertz absorber utilizing periodic cross-shaped graphene arrays.
• To investigate the underlying physical mechanism responsible for the dual-band absorption.
• To explore methods for tuning and optimizing the absorption characteristics.

Main Methods:

• Fabrication of periodic cross-shaped graphene arrays.
• Theoretical modeling using the Fabry-Pérot (F-P) cavity model.
• Numerical simulations to analyze electromagnetic response and absorption spectra.
• Experimental characterization of the fabricated absorber.

Main Results:

• The proposed structure exhibits dual-band absorption enhancement due to edge graphene plasmon (EGP) resonance.
• The Fabry-Pérot (F-P) cavity model accurately predicts the positions of the absorption peaks.
• Simultaneous tuning of absorption bands is achieved by altering the Fermi level of graphene.
• Independent tuning of absorption bands is possible by adjusting the width or length of the graphene cross-arm.
• The absorber demonstrates excellent angle-insensitivity for both transverse electric (TE) and transverse magnetic (TM) polarizations.

Conclusions:

• The developed dual-band THz absorber based on graphene arrays offers a promising solution for THz applications.
• The precise control over absorption bands through structural and electronic modifications is demonstrated.
• The design exhibits robust performance across wide angles and polarizations, highlighting its practical potential.