Graphene-Based Tunable Metamaterial Absorber for Terahertz Sensing Applications

Terahertz (THz) absorbers, vital in advanced materials and photonics, manipulate electromagnetic waves within the 0.1 to 10 THz frequency range. These absorbers, crafted from nanostructures and metamaterials, offer applications in imaging, sensing, and communications. Diverse absorber strategies, including metamaterial-based, plasmonic, graphene-based, and photonic crystal, exploit unique physical phenomena for exceptional THz absorption. The evolution of these absorbers is propelled by advancements in fabrication techniques and computational modeling. Graphene, a two-dimensional carbon material, stands out for terahertz applications with broadband absorption, ultrafast response time, and tunability. This study presents two model graphene-based THz absorbers, designed and simulated using finite element method (FEM). The first model, in the mid-infrared range (6 to 14 μm), finds applications in thermal imaging, remote sensing, and spectroscopy. The second model, in the far-infrared range (1 to 14 THz), is versatile for spectroscopy, imaging, communication, and sensing. Key contributions include a meta-atom with the smallest footprint, a practical absorber design, and tunability through the graphene layer’s chemical potential. Numerical analysis and simulations demonstrate effective absorption, and sensitivity analysis shows the impact of analyte refractive index and thickness on sensing performance. Model 2, focusing on tunable graphene absorbers, exhibits remarkable absorption characteristics, achieving tunable absorptivity from 3 to 99.5