Fig. 1. Schematic of all-dielectric meta-device for generating dynamic Airy beam.

Fig. 2. Characteristic of the meta-device. (a) The optical characteristics of the nanoantenna. The phase can encompass a complete 2π cycle as the diameter transitions from 50 nm to 113 nm, achieving an efficiency exceeding 90% for all the selected nanoantennas. The inset depicts the schematic of the nanoantenna. (b, e) The phase profiles of the first (b) and the second (e) metasurface. (c, f) The optical images of the fabricated metasurfaces according to the phase profile in (b) and (e), respectively. (d, g) The measured phase profiles of the fabricated metasurfaces. Scalar bars: 200 µm. The phase profile is measured using MetronLens from Ideaoptics Co., Ltd, Shanghai. (h) Scanning electron microscope (SEM) images of the meta-device. Scale bar: 100 μm. (i) Tiled-view (blue square) zoomed-in SEM image of meta-atoms of the metasurface. Scale bar: 0.5 μm.

Fig. 3. The simulated and experimental results of the meta-devices. (a) The phase obtained upon the superposition of the two metasurfaces when the rotation angles of the two metasurfaces are both zero. (b) The simulated results when the rotation angle is set as shown in (a). The left column shows the Airy beam intensity in the propagation direction, and the dashed line shows the focal plane. The intensity distribution of the focal plane is shown in the upper right. The lower right shows the intensity distribution of the line that crosses the focal spot indicated by the dashed line in the upper right. (c) The experimental results according to those shown in (b). (d) The phase obtained upon superposition of the two metasurfaces when the rotation angles are -π/2 and π/2, respectively. (e) The simulated results when the rotation angle is set as shown in (d). The left column shows the Airy beam intensity in the propagation direction, and the dashed line shows the focal plane. The intensity distribution of the focal plane is shown in the upper right. The Lower right shows the intensity distribution of the line that crosses the focal spot indicated by the dashed line in the upper right. (f) The experimental results according to those shown in (b).

Fig. 4. The experimental results of the meta-devices. (a) Different focal spots of the Airy beam when varying the rotation angles of the metasurfaces. The theoretically achievable zone is marked between the two dotted circles. (b) The intensity distributions of the focal plane selected from Fig. 4(a) are indicated by squares of different colors. Scalar bar: 20 µm.