Graphene-enhanced polarization-independent high-Q terahertz metamaterial absorber with tunability for sensing applications

Abstract

Terahertz metamaterial absorber (TMMA) has broad prospects for sensing applications. To achieve high sensitivities and low detection limits in practice, a TMMA should exhibit a high Q-factor preferably independent of polarization, tunability, and consists of simple structures that are easy to realize. However, simultaneously achieving these is difficult. Here, we propose a graphene-enhanced TMMA that exhibits a high Q-factor independent of polarization with tunability, using couplings between a continuous monolayer graphene and the underneath metallic fractal structures with rotational symmetry. Simulation results show that the TMMA exhibits dual-band absorption with broad tunability from ∼1.5 to 3.0 THz. A maximum polarization-independent Q-factor of 133.12 with a maximum frequency sensitivity (S) of 0.42 THz/RIU and a figure of merit of 18.28 RIU-1 are achieved theoretically. The presented graphene-enhanced TMMA has many potential applications, particularly in the field of chemical and biological sensing.