Fig. 1. Schematic representation of the designed Moiré device 1 for on-demand wavefront shaping. (a) Conceptual illustration of the proposed Moiré device 1, comprising two layers of mechanically rotated all-dielectric metasurfaces (Layer 1 and Layer 2). (b) Phase distribution of Layer 1 at a mutual twisted angle (α) of 90°, along with the corresponding phase distributions of Layer 2 in the LCP and RCP channels, and the resultant joint phase profiles. (c) Electric field distributions monitored in the orthogonal circular polarization channels on the xoy and xoz planes. (d) Focal length and NA as a function of the mutual rotation angle (α).

Fig. 2. Transmission properties of the selected meta-atoms used to assemble the Moiré device 1. (a) Side and top views of the meta-atoms employed to construct Layer 1 with polarization maintaining properties. (b) Transmission amplitudes and phase delays of cylindrical dielectric pillars labeled from 1 to 8 that satisfy the 2π phase coverage. (c) Normalized magnetic field distributions for cylindrical dielectric pillar with periodic boundary conditions. (d) Side and top views of the meta-atoms employed to construct Layer 2 with polarization converting properties. Transmission amplitudes and phase delays of rectangular dielectric pillars labeled from 1 to 15 that satisfy the 2π propagation phase coverage under (e) x-LP and (f) y-LP incidence. (g) In-plane rotation angles corresponding to the selected 15 rectangular dielectric pillars were used to generate geometric phase profiles. (h) Normalized magnetic field distributions for rectangular dielectric pillars with periodic boundary conditions.

Fig. 3. Encoded phase profiles and generated electric field distributions of Moiré device 1. (a) Encoded phase distributions of Layer 2 within the LCP→RCP channel. (b) Encoded phase distributions of Layer 1 under different twisted angles from 90° to 240°. (c) Joint encoding phase distributions and (d) the produced focusing field distributions carrying the topological charge l=0 within the LCP→RCP channel. (e) Encoded phase distributions of Layer 2 within the RCP→LCP channel. (f) Encoded phase distributions of Layer 1 under different rotation angles from 90° to 240°. (g) Joint encoding phase distributions and (h) the produced focusing field distributions carrying the topological charge l=1 within the RCP→LCP channel. (i) Focal length and NA as a function of relative twisted angle α, including theoretical predictions and simulation results. (j) Focusing efficiencies calculated in different polarization channels.

Fig. 4. Simulation results of the designed Moiré device 2 under x-LP and y-LP incidence. (a) Conceptual illustration of the proposed Moiré device 2, comprising two layers of mechanically rotated all-dielectric metasurfaces (Layer 1 and Layer 2). (b) Electric field and phase distributions under (b) x-LP illumination and (c) y-LP illumination, as the relative rotation angle α gradually increase from 90° to 240°.

Fig. 5. Characterization of THz near-field scanning spectroscopy system and fabricated samples. (a) Schematic diagram of the THz time-domain scanning spectroscopy system. SEM photographs of the fabricated samples, including (b) Layer 1 and (c) Layer 2 of Moiré device 2.

Fig. 6. Experimental results of Moiré device 2. (a) The obtained electric fields and phase distributions under the x-LP incidence and (b) y-LP incidence, as the twisted angle α increases. (c) Focal length and (d) NA as a function of the relative twisted angle α, including theoretical, simulated, and experimental results. (e) Focusing efficiency, obtained through simulations and experiments under x-LP and y-LP illuminations.

Fig. 7. Simulation results of Moiré device 1. (a) The obtained phase distributions in the xoy-plane and electric fields in the xoz-plane as well as the change in focal length as the rotation angle α increases from 90° to 240° at 30° intervals under LCP incidence and (b) RCP incidence.

Fig. 8. Angular-dependent APEs for focal length and NA in Moiré device 1, computed from simulation-theory comparisons across six rotational configurations (90°, 120°, 150°, 180°, 210°, 240°).

Fig. 9. Crosstalk values obtained at orthogonal circular polarization incidence for different rotation angles (90°–240°); red bars for RCP incidence, blue bars for LCP incidence.

Fig. 10. Simulation results of Moiré device 2. (a) The obtained electric fields in the xoz-plane as well as the change in focal length as the rotation angle α increases from 90° to 240° at 30° intervals under x-LP incidence and (b) y-LP incidence.

Fig. 11. Experimental details of Moiré device 2. (a) The GCT-090101 modules embedded in metasurface sample Layer 1 and Layer 2 and (b) coaxially aligned GCT-090101 modules.

Fig. 12. The APEs between simulated and experimental values for focal length and NA across angular displacements spanning 90° to 240° (30° increments).