High-performance tunable and switchable THz metasurface with ultra-wideband from 0.3 to 20 THz for advanced electromagnetic applications

Abstract

Although graphene-based tunable broadband terahertz (THz) absorbers have attracted considerable interest, further study is required to improve their functionality for versatility in diverse applications. In this study, a tunable and switchable Bi-layer Graphene Multi-Functional Metasurface Absorber (BGMFMA) is proposed, which is composed of graphene and VO2. The proposed BGMFMA exhibits tunable properties through dynamic adjustments of the Fermi energy level (chemical potential) of graphene, while the phase transition of VO2 enables the absorption of BGMFMA to switch to narrowband absorption. The findings show that the absorber achieved a perfect absorption of 19.7 THz bandwidth in the range of 0.3–20 THz with absorptance of over 90%. While switching to narrowband absorption, the absorber obtained two narrowband peaks at 4.06 and 9.55 THz with maximum absorptance of 98.4% and 66%, respectively. Moreover, it exhibits polarization insensitivity to incident THz waves and sustains a high absorption rate even at a high incident angle of 60°. The proposed BGMFMA has expectedly been a promising application in fields such as sensing, imaging, detection, 6G communication, and specifically in biomedical fields.