Spatial aliasing based complementary meta-gratings for the high-efficient generation of different polarized multiple beams.

Abstract

We demonstrate the synthesis of split dual circularly polarized (CP) beams with an additional linearly polarized (LP) radiation simultaneously from dual superposed birefringent meta-surface lenses formed of zebra crossing shaped meta-gratings. More specifically, each of the meta-surface lens is capable of generating birefringent CP refractions with different helicities and will readily achieve triple beams of different polarizations when a couple of left-hand CP (LHCP) and right-hand CP (RHCP) lobes radiating in the same direction. Polarization states of such triple-beam radiations can be specifically defined, and the vibrating electric field of each beam would thus be prescribed to form the LHCP and RHCP waves as well as a co- /cross-LP wave. Especially, we show that such a spatial aliasing of dual superposed birefringent meta-surface lenses will achieve promising aperture efficiencies for the multiple-beam generation on the basis of the complementary arrangement of different meta-gratings, and should thus pave the way for more advanced spatial-phase engineering with specific radiating characteristics using meta-surfaces.