Fig. 1. Schematic diagram of the dual-band tunable chiral metasurface structure. (a) Three-dimensional schematic of the metasurface array; (b)(c) front view and perspective view of the unit cell structure

Fig. 2. Electromagnetic response curves of the metasurface to two types of circularly polarized light. (a) Reflection coefficients; (b) absorption spectra and CD spectrum

Fig. 3. Two methods for tuning chiral response. (a) CD effect corresponding to different VO₂ conductivities; (b) CD effect under different dielectric layer thicknesses

Fig. 4. Electric field (E) and current distributions (J) under circularly polarized light incidence at the resonance frequency of 1.93 THz with the VO₂ structure in metallic and non-metallic states. (a)(c) Electric field distributions under LCP light incidence; (b)(d) electric field distributions under RCP light incidence; (e)(g) current distributions under LCP light incidence; (f)(h) current distributions under RCP light incidence

Fig. 5. Effect of structural parameter variations on CD. (a) Length of the gold rectangular patch l₁; (b) length of the VO₂ rectangular patch l₂; (c) period of the unit cell P; (d) thickness of the top layer h₂

Fig. 6. Impact of the incident angle on CD

Fig. 7. Application in near-field digital imaging. (a) Array composed of 16×16 metasurface unit structures; (b) near-field distributions of the array under the incidence of circularly polarized lights at 1.91 THz and 3.78 THz