Fig. 1. Unit structure of metamaterial absorber

Fig. 2. Permittivity of graphene varies with frequency at different Fermi levels. (a) Real part of graphene's permittivity; (b) imaginary part of graphene's dielectric constant

Fig. 3. Absorption curve of absorber

Fig. 4. Real and imaginary parts of the relative impedance of the absorber

Fig. 5. Electric field distribution at frequency 7.224 THz. (a) Electric field distribution in layer VO₂; (b) electric field distribution on the graphene layer; (c) electric field distribution on the side

Fig. 6. Electric field distribution at frequency 8.7718 THz. (a) Electric field distribution in layer VO₂; (b) electric field distribution on the graphene layer; (c) electric field distribution on the side

Fig. 7. Influence of the structural parameters of absorber on the absorption rate. (a) Thickness of medium layer t changes; (b) thickness t₁ of topas changes; (c) change of graphene sheet length P₁; (d) change of radius R₃ of VO₂ small circle; (e) change of radius R₂ of VO₂ big circle; (f) VO₂ opening length x is changed

Fig. 8. Influence of VO₂ conductivity on absorption rate

Fig. 9. Effect of Fermi level (μc) on the absorption rate of graphene

Fig. 10. Absorption rate corresponding to incident angles under different polarization angles and modes. (a) Absorption rate corresponding to different polarization angles; (b) absorption rate corresponding to different incidence angles in TE mode; (c) absorption rate corresponding to different incidence angles in TM mode