Versatile Airy-Beam Generation Using a 1-Bit Coding Programmable Reflective Metasurface

The Airy beam, known to present particular unique features, such as diffraction-free, self-healing, and self-bending, has attracted considerable interest in recent years. Here, an electronically controlled reflective coding metasurface is exploited to generate and dynamically manipulate the Airy beam over a wide frequency band in the microwave regime. By judiciously controlling the external dc bias voltage applied to the programmable metasurface, two distinct control states, ``0'' and ``1'', are engineered as digital codes for \ensuremath{-}\ensuremath{\pi}/2 and +\ensuremath{\pi}/2 phase responses, respectively. The programmable binary-phase-coding metasurface enables the generation and active reshaping of the Airy beam to be numerically simulated and experimentally validated. Moreover, the metasurface allows the bandwidth limitation of passive counterparts to be overcome and is able to modulate electromagnetic waves over a broad frequency range, spanning from 9 to 12 GHz, to realize diffraction-free Airy beams.