Fig. 1. Broadband and narrowband tunable absorber based on graphene interdigital structure. (a) Graphene interdigital structure array diagram; (b) unit structure and voltage modulation schematic; (c) x-y top view of the plane structure; (d) absorption curves in 0.5‒4.3 THz

Fig. 2. Comparison of different absorption curves and the variation of electrical conductivity with frequency and Fermi level. (a) Different graphene structure layers; (b) real part of electrical conductivity at τ=1.0 ps; (c) imaginary part of electrical conductivity at τ=1.0 ps; (d) real part of electrical conductivity at τ=0.6 ps; (e) imaginary part of electrical conductivity at τ=0.6 ps

Fig. 3. Relative impedance Z and x-y plane electric field distributions in different structural layers. (a) Broadband mode; (b) narrowband mode; (c) F=1.87 THz; (d) F=2.57 THz; (e) F=1.32 THz; (f) F=2.67 THz; (g) F=1.77 THz; (h) F=3.69 THz; (i) F=1.56 THz; (j) F=3.21 THz; (k) F=1.75 THz; (l) F=2.99 THz; (m) F=1.36 THz; (n) F=2.21 THz

Fig. 4. Influence of structural parameters in broadband and narrowband mode. (a) Interdigitated arm length L₂; (b) interdigitated arm width W₁; (c) number of interdigital pairs; (d) dielectric layer thickness H₂

Fig. 5. Influence of polarization angle and incidence angle on absorption. (a)(c) Broadband operating mode; (b)(d) narrowband operating mode

Fig. 6. Effect of Fermi energy levels on absorption and absorption bandwidth. (a)(c) Broadband operating mode; (b)(d) narrowband operating mode