Fig. 1. Schematic of hybrid graphene-vanadium dioxide based metamaterial terahertz broadband absorber geometry. (a) Perspective view of the unit cell; (b) top view of the unit cell

Fig. 2. Absorption spectra of the proposed absorber and real and imaginary parts of the relative impedance

Fig. 3. Surface current distribution of the proposed broadband absorber at 1.87 THz and 2.98 THz, respectively (E_f=0.7 eV, σ(VO₂)=200000 S/m). (a) Top layer; (b) bottom layer

Fig. 4. Real and imaginary parts of surface impedance of graphene, and the absorption spectra of the designed broadband absorber. (a) Real part of surface impedance; (b) imaginary part of surface impedance; (c) absorption spectra

Fig. 5. Real and imaginary parts of permittivity of vanadium dioxide at different conductivities, and the absorption spectra of vanadium dioxide. (a) Real part; (b) imaginary part; (c) absorption spectra

Fig. 6. Real and imaginary parts of the relative impedance of broadband absorber at different conductivities. (a) Real part; (b) imaginary part

Fig. 7. Simulated absorption spectra of the proposed broadband absorber at different Fermi energies and conductivities of vanadium dioxide, and the side view of the electric field intensity of broadband absorber at 2.98 THz. (a) Absorption spectra; (b) side view of the electric field intensity

Fig. 8. Absorption spectra and reflection and transmission curves. (a) Absorption spectra of single-layer graphene with and without the pattern in the free space; (b) reflection and transmission curves of the ToPaS layer; (c) absorption spectrum of ToPaS-vanadium dioxide structure; (d) absorption spectra of the proposed broadband absorber with and without patterned graphene

Fig. 9. Absorption spectra of the proposed broadband absorber at different polarization angles

Fig. 10. Absorption spectra of the proposed broadband absorber at different incident angles. (a) TE polarization; (b) TM polarization

Fig. 11. Schematics of oblique incidence in different modes. (a) TE mode; (b) TM mode

Fig. 12. Equivalent circuit diagram and absorption spectra. (a) Equivalent circuit diagram of the proposed broadband absorber; (b) transmission line theory calculated and CST simulated absorption spectra