Non-Diffraction Self-Acceleration Beams With Customized Transverse Intensity Profiles Based on 3-D-Printed Meta-Structure

In this article, two 3-D-printed all-dielectric meta-structures that can produce diffraction-free self-acceleration beams with different transverse intensity profiles are proposed in the microwave frequency band. The first single-layer meta-structure, combining the Fourier lens phase and cubic phase distributions, is engineered to generate Airy beams with highly asymmetric transverse intensity profiles. In order to flexibly customize the propagation trajectory and transverse spot shape, Bessel-like beams with symmetric transverse profiles along arbitrary trajectories are realized by the second compact meta-structure based on phase synthesis. Calculating the phase mask of the metasurface is the most critical part. In this work, phase-modulated meta-structures can map the phase information to height distribution of the cube elements that can be precisely controlled. To verify the validity, two prototypes are printed and measured. From the beam intensities at different cross sections along the propagation trajectory, the oscillating multilobe intensity pattern of the 2-D Airy beam and the symmetric non-spreading central main lobe of the Bessel-like beam can be observed in simulation and measurement. Besides that, two kinds of beams have transverse acceleration behavior and self-reconstruction property. Therefore, the proposed meta-structures have great potential in numerous challenging fields, like microwave power transmission, secure communication, imaging, and detection.