Fig. 1. Schematic diagram of the metasurface unit structure

Fig. 2. Absorption rate with changes in metasurface unit structure parameters

Fig. 3. Flowchart of inverse design of metasurface structure based on PSO

Fig. 4. Absorption spectra of TE mode and TM mode when terahertz waves are vertically incident

Fig. 5. Surface electric field E and current distribution J of metasurface absorber under vertical incidence

Fig. 6. Relative impedance spectra of metasurface absorber

Fig. 7. Absorption spectra of TE mode and TM mode when terahertz waves are obliquely incident at an angle of α

Fig. 8. Surface electric field Eand current distribution Jof metasurface absorber under oblique incidence at 60° and 85°