Fig. 1. The absorber (a) 3D schematic; (b) top view; (c) side view

Fig. 2. (a) Reflection spectrum; (b) absorption spectrum; (c) real part of and (d) imaginary part of the relative impedance with different conductivities of VO₂

Fig. 3. Reflection and absorption spectra, real part and imaginary part of relative impedance when the conductivity of vanadium dioxide is 2×10⁵ S/m

Fig. 4. The influence of the structural parameters of the absorber cell: (a) the opening angle α; (b) the thickness of the upper PI medium Z₃ and (c) the radius of the VO₂ disk R_2, on the terahertz absorptivity at the conductivity of 2×10⁵ S/m

Fig. 5. Electric field intensity distribution at the two absorption peak frequencies of 1.53 THz and 2.12 THz under TE mode

Fig. 6. (a) The absorption of the wide-band absorber with TE polarization at different incident angles; (b) the absorption of the wide-band absorber with TM polarization at different incident angles; (c) the absorption spectrum of the wide-band absorber with different polarization angles; at the conductivity of 2×10⁵ S/m

Fig. 7. Reflection and absorption spectra, real part and imaginary part of relative impedance when the conductivity of vanadium dioxide is 200 S/m

Fig. 8. The influence of the structural parameters of the absorber cell: (a) the opening angle; (b) the thickness of the lower PI medium Z₁ and (c) the width of the metal split ring resonator W, on the terahertz absorption at the conductivity of 200 S/m.

Fig. 9. Electric field intensity distributions at the three absorption peak frequencies of 2.54 THz, 2.93 THz and 3.34 THz under TE mode

Fig. 10. Absorption spectra of narrow-band absorbers with different polarization angles at the conductivity of 200 S/m