Ultra-wideband two-dimensional Airy beam generation with an amplitude-tailorable metasurface

Airy beams, accelerating optical beams with exotic properties of self-bending, self-healing and non-diffraction, are essential for a wide range of photonics applications. Recently, metasurfaces have provided an efficient platform for generating desired Airy beams within a thin thickness, but they suffer from the narrow bandwidth, especially for two-dimensional (2D) Airy beams. Here, we propose an amplitude-tailorable polarization-converting metasurface to enable ultra-wideband 2D Airy beam generation. The amplitude and phase profiles for the 2D Airy beam can be realized by tuning only the orientation of the multi-resonant meta-atom, which can operate in the range of 6.6 GHz to 23.7 GHz, or fractional bandwidth of 113%. An exemplary prototype is measured to validate the design principle, which is in agreement with the simulation results. The proposed method holds great promise for wavefront shaping, and may facilitate the uses of Airy beam for practical applications.