Fig. 1. Structural diagrams of proposed absorber. (a) Perspective view of single unit cell; (b) top view of top structure; (c) top view of middle structure; (d) side view of unit cell

Fig. 2. Complex permittivities of BDSs at different Fermi level energies. (a) Real part; (b) imaginary part

Fig. 3. Calculated performances of proposed dual-band absorber for VO₂ in insulating state. (a) Reflectivity、transmissivity, and absorptivity; (b) relative impedance

Fig. 4. Electric field distributions for VO₂ in insulating state. (a) Middle structure at peak 1; (b) top structure at peak 1; (c) middle structure at peak 2; (d) top structure at peak 2

Fig. 5. Calculated performances of proposed dual-band absorber for VO₂ in metallic state. (a) Reflectivity、transmissivity, and absorptivity; (b) relative impedance

Fig. 6. Electric field distributions at resonance frequency point of 4.246 THz for VO₂ in metallic state. (a) Top structure；(b) middle structure

Fig. 7. Absorptivity versus thickness of dielectric layer for VO₂ in different states. (a) (b) Insulating state；(c) (d) metallic state

Fig. 8. Absorptivity versus Fermi level energy for VO₂ in different states. (a) Insulating state; (b) metallic state

Fig. 9. Absorptivity versus incident angle under TE mode. (a) When VO₂ is in insulating state; (b) when VO₂ is in metallic state