Wideband absorption and dual-band biosensing in a reconfigurable VO 2 –graphene metamaterial assisted by explainable Artificial Intelligence

This study presents a reconfigurable VO2-graphene metamaterial absorber for terahertz applications, comprising interconnected VO2 square rings and a central graphene ring on a SiO2 substrate backed by gold. The optimized design achieves over 90% broadband absorption from 0.9075 to 6.6375 THz, yielding a 5.73-THz bandwidth. Removing the interconnection produces dual-band absorption with near-unity peaks at 2.3789 and 5.624 THz. Refractive-index sensing achieves a maximum sensitivity of 1.875 THz/RIU and a figure of merit (FOM) of approximately 98.17 RIU−1. Polarization response, angular stability, and electromagnetic shielding performance are also investigated. An equivalent circuit model and electric-field analysis elucidate the absorption mechanism. Furthermore, XGBoost-based machine learning predicts absorber performance, while SHAP analysis identifies influential design parameters. These results demonstrate the potential of the proposed absorber for multifunctional terahertz applications.