Dynamically tunable electromagnetically induced reflection in terahertz complementary graphene metamaterials

We presented a dynamically tunable electromagnetically induced reflection (EIR) based on the complementary graphene metamaterials composed of the wire-slot and split-ring resonators slot (SRRs-slot) array structures for the terahertz region. In this structure, the dark mode excited by the near field coupling between wire-slot and SRRs-slot structures, induces a reflection window. Moreover, the reflection window can be actively controlled by varying the lateral displacement between two slot-type resonant structures or Fermi energy of graphene without reoptimizing and re-fabricating structure. In addition, the large positive group delay obtained within the reflection peak can be also tuned over a broad terahertz region by changing the Fermi energy of graphene. Therefore, the work opens up the possibility for the development of compact elements such as modulators, tunable sensor, switches and slow light devices. (C) 2015 Optical Society of America