Full-space polarization-regulated lightwave steering via single-layer metasurfaces

Metasurfaces can offer unprecedented superiority in manipulating the wavefront of electromagnetic waves and have attracted much attention around the world. However, to date, most of the metasurfaces reported only operate in either transmission or reflection space, leaving half of the space unexplored. Here we propose a general scheme for designing full-space polarization-regulated wavefront steering via single-layer metasurfaces. Specifically, the designed metasurface can change its functionality and working space (from transmission space to reflection space and vice versa) by varying the incident polarization. For a proof of concept, we demonstrate numerically two full-space polarization-regulated metasurfaces. As incident x-polarized light changes to y-polarized light, the functionality of two devices is switched from a reflected metalens and an Airy bean generator to a transmitted focusing vortex generator and a metalens, respectively. Here the design strategy is generalized and can be adapted to design other polarization-regulated meta-devices at other wavelengths. In regard to wavefront control, these results significantly expand the scope of metasurfaces, providing new possibilities to develop full-space multifunctional meta-devices. (paper)