Jing Liqiao, Liao Dashuang, Tao Jie, Chen Hongsheng, Wang Zuojia
Opt Lett. 2022 Jun 1;47(11):2790-2793. doi: 10.1364/OL.460106.
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-π 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.
超表面最近已成为一个强大的平台，用于在中尺度上设计自由电子辐射的波包。在此，我们提出当移动电子与双各向异性超表面相互作用时，可以产生艾里光束。通过改变固有耦合强度，可以从超原子实现史密斯-帕塞尔辐射的全幅度覆盖和0到π的相位切换。这种不寻常的特性使组装好的艾里光束的波前向抛物线轨迹移动。实验表明，在开槽波导处受限的倏逝场可以通过来自设计的双各向异性超表面的史密斯-帕塞尔辐射耦合到艾里光束中。我们的方法和设计策略为具有无衍射、自加速和自愈合光束特性的自由电子激光器提供了一条替代途径。
