Water-Based Graphene Terahertz Ultrawideband Absorbers Exhibit Angular Insensitivity

In this study, we introduce a novel water-based graphene terahertz (THz) metamaterial absorber. The design comprises a graphene layer, water, and a photosensitive resin material. Our simulation experiments revealed that, under specific conditions, the absorber achieves an absorption rate exceeding 90% within the 4.08–7.38 THz range, corresponding to a relative bandwidth of 58%. Notably, when compared to its anhydrous counterpart, the aqueous graphene absorber exhibited a 37.8% enhancement in the absorption bandwidth, surpassing 90%. Moreover, the absorber demonstrates over 80% absorption across a 0–45° incidence angle and exhibits excellent polarization insensitivity; the absorption remains above 90% throughout a 0–90° polarization angle variation. These characteristics render these absorbers promising for applications in sensors, thermal detectors, and terahertz imaging.