Low-Terahertz Transparent Graphene-Based Absorber

Area of Science:

• Optoelectronics and Photonics
• Materials Science
• Electromagnetics

Background:

• Development of efficient absorbers for terahertz (THz) frequencies is crucial for various applications.
• Existing absorbers often rely on metallic components, limiting transparency and flexibility.
• Graphene-based materials offer tunable electromagnetic properties and potential for metal-free designs.

Purpose of the Study:

• To propose and analyze a novel, transparent, and metal-free absorber for low-terahertz applications.
• To investigate the absorption characteristics of multilayer graphene/dielectric laminates (GLs).
• To develop an analytical method for optimizing absorber performance across different frequency ranges.

Main Methods:

• Design of a multilayer absorber structure comprising graphene/dielectric laminates (GLs) and polyethylene terephthalate (PET) layers.
• Modeling GLs as homogeneous-equivalent single layers (ESLs) with tunable sheet resistance (R).
• Utilizing an innovative analytical method to select optimal R values for absorption enhancement.
• Numerical computation of absorption, reflection, and transmission coefficients up to 4 THz.
• Consideration of realistic sheet resistance values for chemically doped graphene monolayers.

Main Results:

• The proposed absorber achieves a peak absorption coefficient of approximately 0.8 at 1.1 THz.
• A wide bandwidth of 1.4 THz centered at 1.5 THz with a reflection coefficient below -10 dB.
• High optical transmittance greater than 86% across the visible spectrum.
• Demonstrated feasibility for both low-gigahertz and low-terahertz frequency applications.

Conclusions:

• The developed multilayer graphene/dielectric laminate absorber is a promising transparent and metal-free solution for terahertz applications.
• The analytical method provides an effective approach for optimizing absorber performance.
• The design exhibits excellent absorption properties and high optical transparency, paving the way for novel optoelectronic devices.