Generation of Airy beams in Smith-Purcell radiation

The metasurface has recently emerged as a powerful platform to engineer wave packets of free electron radiation at the mesoscale. Here, we propose that Airy beams can be generated when moving electrons interact with bianisotropic metasurfaces. By changing the intrinsic coupling strength, full amplitude coverage and 0-to-pi phase switching of Smith-Purcell radiation can be realized from the meta-atoms. This unusual property shifts the wave front of the assembled Airy beam toward a parabolic trajectory. Experimental implementation displays that evanescent fields bounded at slotted waveguides can be coupled into Airy beams via Smith-Purcell radiation from a designed bianisotropic metasurface. Our method and design strategy offer an alternative route toward free-electron lasers with diffraction-free, self-accelerating, and self-healing beam properties. (C) 2022 Optica Publishing Group

Automated summary

The study proposes a method to generate Airy beams by using bianisotropic metasurfaces interacting with moving electrons. By adjusting the coupling strength, full amplitude coverage and phase switching of Smith-Purcell radiation can be achieved, which shifts the wave front of the assembled Airy beam towards a parabolic trajectory. Experimental results demonstrate that evanescent fields bound in slotted waveguides can be coupled into Airy beams through Smith-Purcell radiation from designed bianisotropic metasurfaces. This method and design strategy offer an alternative route towards free-electron lasers with diffraction-free, self-accelerating, and self-healing beam properties.