| Because of the unique property of penetrability and low loss,the terahertz wave shows a vast potential for future application,including information communication technology,biomedicine,physics and materials science.The terahertz wave absorption enhancement and terahertz wave polarization converter are two of the most important application,which are usually based on nanostructured graphene.However,nanostructured graphene can unavoidably cause edge effect,such as unordered scattering losses,which might be negative effect for absorption enhancement and polarization conversion.We studied the terahertz wave absorption and polarization conversion based on nonstructured graphene in this article,and the main points are as the following:1.Based on the perfect absorption of asymmetric Fabry-Perot(F-P)resonator,we concluded that exciting the graphene surface plasmonic resonance is an effective way to achieve perfect absorption,and that the broadband perfect absorption in graphene is related to the broadband linewidth of graphene plasmonic resonance.The theory of broadening linewidth of perfect absorption using far-field interaction was proposed.The broadband near-perfect absorber working in terahertz frequency was designed,which is based on periodical dielectric loaded nonstructured graphene.The calculation results verified its broadband and near-perfect absorption function.Furthermore,we also studied the influence of incident angle,Fermi energy of graphene and geometrical parameters on its absorption outcome.2.The theory of polarization conversion based on anisotropic graphene surface plasmonic resonance was analyzed.The reflecting polarization conversion in terahertz region was designed,which is based on periodical rectangular dielectric loaded nonstructured graphene.The calculation verified its polarization conversion function.Moreover,we also studied the influence of graphene Fermi energy and geometrical parameters on its polarization conversion outcome. |
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