A switchable THz perfect absorber using graphene-based metamaterials

A switchable THz absorber, with absorbance more than 90% is proposed, and numerically characterized. The absorber structure is based on metamaterials with unit cells consisting of two patterned graphene layers separated by a 5-nm thick layer of Al₂O₃. Numerical results show that when the chemical potential of the top graphene microribbons are tuned by an external variable bias and that of the lower graphene fishnet is kept at μ_C=0, frequency of the absorption peaks can be tuned as desired, therefore we can have tunable or switchable absorbers.