Flexible control of highly‐directive emissions based on bifunctional metasurfaces with low polarization cross‐talking

Achieving flexible and highly directive emissions toward pre-designed directions has intrigued long-held interest in both science and engineering community, but most available efforts suffer the issues of bulky size, limited functionalities, and low efficiency. Here, we propose a general strategy to efficiently and flexibly control the emission beams with dual functionalities realized independently by orthogonal excitations. To overcome the polarization cross-talking, a novel planar multi-mode anisotropic meta-atom is designed by incorporating the screening effect of a surrounding wire loop. As the result, we can design the polarization-dependent phase profile under certain polarization, without worrying about their influences on the other polarization. As an illustration, two proof-of-concept metasurfaces are actualized at microwave frequencies, of which one combines the functionalities of focused-beam and large-angle multibeam emissions while another hybrids the functionalities of beam-steering and small-angle multibeam emissions. Theoretical, full-wave simulation, and experimental results are in excellent agreement with each other, which collectively demonstrate the desired performances of our bifunctional devices. Our proposed strategy paves the way to realize high-performance multifunctional optical devices with high integration and complex wavefront manipulations.