The construction of versatile terahertz metamaterial having tunable dual-band electromagnetically induced transparency based on two falling asymmetric T-shaped graphene resonators

Abstract

The combination of graphene and metamaterials has played an important role in studying tunable terahertz functional devices, with electromagnetically induced transparency (EIT) being one of the typical examples. In this work, we present a versatile terahertz meta-device consisting of two asymmetric T-shaped graphene resonators, which could produce a dual-band EIT effect. The strong interaction between the two T-shaped graphene resonators leads to a dual-band EIT effect, and the electric field and surface current distributions are provided to reveal their generation mechanisms. Results also indicate that the dual-band EIT effect is not only influenced by size variations of T-shaped graphene resonators themselves, but also strongly depends on the Fermi energy levels they utilized. Interestingly, multi-frequency switching with a maximum modulation depth of 85.13 % could be further realized when the Fermi energy levels are precisely controlled. The group delay near two transmission peaks can reach 2.87 ps and 4.20 ps, which is important for the study of slow light devices. Besides, the sensitivity of the graphene-based dual-band EIT device as a sensor reaches 109 GHz·RIU−1 and 145 GHz·RIU−1, indicating that the design has excellent sensing performance and is expected to be useful for the detection of biomolecules in biochemistry, medicine and other industries.