Fig. 1. Schematic diagram of the voltage-controlled 3D reconfigurable chiral metamaterial. The SMA is covered with a 0.1 mm thick insulating heating film, as shown in the blue part between the feeding vias and the SMA. The DC voltage source adjusts the voltage loaded on the heating film to achieve temperature control by detecting the difference between the temperature of the SMA and the target temperature.

Fig. 2. Schematic diagram of the meta-atom and its transmission spectrum. (a) Schematic of the meta-atom; the optimized parameters are p=48  mm, l1=39  mm, w1=10  mm, l2=15  mm, w2=2  mm, l3=16  mm, w3=3  mm, l4=12  mm, w4=3  mm, w5=2.5  mm, k=0.2  mm, h=1  mm. (b) CD spectrum varying with SMA’s curvature and frequency; transmission spectrum varying with SMA’s curvature and frequency under (c) RCP and (d) LCP wave incidence. The positive (+z direction) or negative (−z direction) curvature indicates only the curving direction of SMA.

Fig. 3. Surface current distribution when (a) 1/ρ=+0.1, (b) 1/ρ=0, and (c) 1/ρ=−0.1 under RCP wave incidence; surface current distribution when (d) 1/ρ=+0.1, (e) 1/ρ=0, and (f) 1/ρ=−0.1 under LCP wave incidence. Electric field distributions (log10|E|) around a meta-atom under (g) RCP wave and (h) LCP wave incidence. Note that the surface currents given are obtained from the simulation with the feeding lines, but the surface currents on the feeding lines are not given here for clarity.

Fig. 4. Surface current distribution. The surface current direction under (a) RCP wave incidence and (b) LCP wave incidence. The surface current intensity under (c) RCP wave incidence and (d) LCP wave incidence.

Fig. 5. Amplitudes of the power scattered by multipole moments. Power scattered by multipole moments under RCP wave incidence when (a) 1/ρ=+0.1, (b) 1/ρ=0, and (c) 1/ρ=−0.1. Power scattered by multipole moments under LCP wave incidence when (d) 1/ρ=+0.1, (e) 1/ρ=0, and (f) 1/ρ=−0.1.

Fig. 6. (a) Measurement setup. Simulated and measured transmission performance under LCP and RCP waves incidence when (b) 1/ρ=−0.1, (c) 1/ρ=0, and (d) 1/ρ=+0.1.

Fig. 7. Simulated transmission spectra of (a) tLR and (b) tRL vary with frequency and curvature.

Fig. 8. (a) SMA’s curvature varies with time. (b) Transmission coefficient of the meta-atom with and without feeding lines. Simulated and measured transmission performance under LCP and RCP waves incidence when (c) 1/ρ=−0.4 and (d) 1/ρ=+0.4.

Fig. 9. The power scattered by Q under RCP wave incidence when (a) 1/ρ=+0.1 and (b) 1/ρ=-0.1. The power scattered by Q under LCP wave incidence when (c) 1/ρ=+0.1 and (d) 1/ρ=-0.1.