Fig. 1. Schematic diagram of graphene metasurface structure. (a) 4×4 array; (b) top view

Fig. 2. Relationship between graphene conductivity and frequency at different Fermi levels

Fig. 3. Metasurface transmission spectrum. (a) Unfilled with graphene;(b) filled with graphene

Fig. 4. Physical mechanism of PIT. (a) Electric field distribution at dip A, f=0.929 THz; (b) electric field distribution at peak B, f=1.016 THz; (c) electric field distribution at dip C, f=1.037 THz; (d) current distribution at dip A; (e) current distribution at peak B; (f) current distribution at dip C

Fig. 5. Dynamic control by the Fermi levels. (a) Transmission spectrum at different Fermi levels; (b) influence of Fermi levels on resonance

Fig. 6. Voltage modulation. (a) Relationship between Fermi levels and bias voltages; (b) relationship between graphene dielectric constant real part and frequency; (c) relationship between gold dielectric constant real part and frequency

Fig. 7. Modulation of structural transmission spectra. (a) Voltage modulation; (b) graphene width modulation

Fig. 8. Dynamic adjustability of the slow light performance. (a) Group delay; (b) group index; (c) relationship between group delay and bias voltage; (d) relationship between the delay bandwidth product and the bias voltage

Table 1. Influence of bias voltage on slow light performance

Table 2. Influence of graphene width on slow light performance when $V_{\mathrm{g}}=\mathrm{30}\mathrm{V}$

Table 3. Comparison of slow light performance between proposed structure and other structures