Multimodal Resonance in Double Graphene for Angle Robust and Tunable Narrow‐Band THz Absorption

This work proposes a multimode resonant terahertz absorber consisting of two patterned graphene layers, two silicon dioxide (SiO 2 ) dielectric layers, and a metal substrate. Simulations and analyses based on the finite element method (FEM) indicate that the absorber achieves near‐perfect absorption at 0.60, 2.42, and 4.79 THz, with corresponding absorption rates of 99.6%, 99.4%, and 99.9%, respectively. The physical mechanisms underlying the resonance peaks are elucidated through analysis of the electric field and surface current distributions at each resonant frequency. The results indicate that the resonance peak at 0.60 THz arises from an electric dipole resonance. While the 2.42 THz peak is attributed to a higher‐order quadrupolar resonance accompanied by magnetic coupling effects. The 4.79 THz resonance arises from a hybrid mode combining higher‐order quadrupolar resonance and a Fabry–Pérot (FP) cavity mode. Moreover, magnetic dipole resonance contributes to all three absorption peaks. This work is expected to significantly advance research in the field of multimode resonance. Furthermore, the absorber demonstrates polarization insensitivity and dynamic tunability, and by investigating the impact of the incident angle, it is found that even when the oblique incident angle reaches 60°, the absorption rate remains above 80%. These properties enable the absorber to play an active role in various fields, including terahertz communication technology, stealth technology, biomedical detection, and imaging, as well as security detection.