High‐efficiency generation of far‐field spin‐polarized wavefronts via designer surface wave metasurfaces
Weikang Pan, Zhuo Wang, Yizhen Chen, Shiqing Li, Xiaoying Zheng, Xinzhang Tian, Cong Chen, Nianxi Xu, Qiong He, Lei Zhou, Shulin Sun
Abstract
Abstract Achieving a pre‐designed scattering pattern from an ultra‐compact platform is highly desired for on‐chip integration optics, but conventional techniques suffer from the limitations of bulky size, wavelength‐scale modulation and low efficiency. Here, we propose a new strategy to efficiently generate arbitrary spin‐polarized scattering far‐field patterns from surface‐wave (SW) excitations on a designer Pancharatnam–Berry (PB) metasurface. We find that a PB meta‐atom serves as a subwavelength scatter to decouple impinging SW to a spin‐polarized propagating wave (PW) with tailored amplitude and phase, and thus interference among PWs generated by scatterings at different PB meta‐atoms can generate a tailored far‐field pattern. As a proof of concept, we design and fabricate a series of PB metasurfaces in the microwave regime and experimentally demonstrate that they can generate desired radiation patterns within a broad frequency band, including unidirectional radiation, line/point focusing, vortex beam and hologram. These findings may stimulate important applications in on‐chip integrated photonics.