Tunable broadband terahertz metamaterial absorber using V3O5

The necessity for new materials capable of adapting to emerging technologies has become a significant challenge. This involves not only the synthesis of such materials but also their functional performance within the little-studied terahertz spectrum. In this paper, we propose a three-part unit cell metamaterial structure. The first layer consists of four L-shaped V3O5 resonators positioned at the corners, with two symmetric meander-line branches situated in the center. These elements serve to facilitate inductive or capacitive tuning, depending on the material state. The second is a SiO2 dielectric layer, and the third is an Au ground reflector. In the conductive state, the structure exhibited more than 90% absorption across two different frequency bands: from 1.60 to 3.02 THz and from 7.63 to 9.09 THz. By modulating the V3O5 conductivity, the proposed metamaterial design can function either as a reflector or an absorber. We analyze the influence of the thickness of the V3O5 and SiO2 layers, revealing their significant impact on the absorption spectra. The absorption phenomena are explored by analyzing the electric field distribution and applying impedance matching theory. In addition, the absorption spectra under different polarization angles show that the structure is insensitive to the direction of the electric field. This proposed absorber represents a new alternative for a wide range of promising applications in terahertz imaging, sensing, and detection.