Research On Tunable Terahertz Metamaterial Device Based On Graphene

Metamaterials in the field of the current defense, economic, medical and other produce increasingly broad and deep impact, was the US "Science" magazine evaluated the past ten years the most significant technological breakthroughs of humanity. With the rapid development of information technology, metamaterials gradually into the application level. However, due to the extraordinary electromagnetic properties of metamaterials is mainly determined by the shape and physical dimensions of the ordered structure units artificially designed, which make exhibit electromagnetic properties is confined to live. Graphene because of its conductivity can be controlled by applying a voltage, which makes it very suitable for applications of tunable terahertz metamaterials. Based on this, we propose three different functional graphene metamaterial devices, namely absorber, electromagnetically induced reflection and sensor. Numerical simulations using commercial software CST microwave studio were carried out:1. We proposed a tunable THz metamater absorber based on periodic single-layer graphene structure. The absorption can reach 99.9% when the graphene was took a appropriate Fermi energy level. More importantly, we found that the absorption peak can be dynamically controlled over a broadband frequency range by adjusting the gate voltage without re-optimizing or re-fabricating the physical structure.2. We presented a dynamically tunable electromagnetically induced reflection metamaterials based on complementary graphene structure. In this structure, the dark mode is excited by the near field coupling between two resonator structures, induces a reflection window. Moreover, the reflection window can be actively controlled by varying the lateral displacement between two resonant structures or Fermi energy of graphene, without re-optimizing and re-fabricating structure. In addition, the large positive group delay obtained within the reflection peak make the work open up the possibility for the development of compact elements such as modulators, tunable sensor, switches and slow light devices.3. We presented an ultrasensitive terahertz sensor based on the complementary graphene metamaterial, the reflection peak with narrow linewidth and high Q-factor and enables ultrasensitive sensing. The simulated results show that the proposed sensor can obtain the frequency sensitivity of 177.7GHz/RIU and FOM of 59.3, respectively. More importantly, the introducing of the complementary graphene metamaterial into this sensor can not only enhance the absorption of biological molecules and sensing performance, but also dynamically tune the sensing range by shifting the Fermi energy. Therefore, this sensor opens up opportunities for EIR metamaterials to be applied as efficient sensing several organic, and biological molecules that have the unique electromagnetic spectrum in the terahertz regime.