Reconfigurable Multiband Co-Planar Nested Electromagnetically Induced Transparent Metamaterial Based on Dual Modulation

Abstract

A multiband co-planar nested electromagnetically induced transparency (EIT) metamaterial based on dual modulation of vanadium dioxide (VO2) and graphene is proposed. The single-layer structure comprises a pair of metallic T-type resonators (TRSs), a pair of VO2-TRS with equal size, and a centrally positioned crossed graphene layer. These three layers of TRS with varying sizes undergo bight-bight coupling, enabling efficient modulation of the three-band EIT-like effect through the combination of VO2 and graphene. Moreover, three distinct modulation mechanisms in the hybrid EIT metamaterials are revealed: 1) the number of EIT windows decreases as the surface temperature falls in the VO2-TRS integration; 2) the centrosymmetry is broken during the I-shaped graphene integration process, allowing dynamic control of EIT switching and transmission strength under different polarization incidences; 3) redistribution of the surface electric field in the crossed graphene layer. The three EIT windows close one by one as the Fermi level increases with a maximum modulation depth (MD) of 89.4%. The designed structure achieves a maximum transmission coefficient of 0.95 and a maximum group delay of 27.6 ps in the terahertz (THz) band, indicating excellent transmission performance and slow-light characteristics. This work demonstrates the potential application of multiband THz slow-light devices and modulators.