Generation of multi-beam reflected from gradient-index metasurfaces

Abstract

Many recent metasurfaces, consisting of one or two-dimensional artificial structures with subwavelength unit cells, have been designed to manipulate optical waves by achieving the 2 pi continuous phase gradients. In this paper, a method to transfer and control multi-beam reflections from a normal incident wave using a gradient-index metasurface is presented. By tuning properly the phase difference over the gradient-index metasurface, multi-beam anomalous reflections can be achieved, where the beam wavefronts are fully controlled by the refractive index distribution. The theoretical and simulated results show that some excellent multi-beam anomalous reflections are demonstrated by field distribution and radiation pattern of scattering field. Our method may help to offer a new design methodology for multi-beam steering in many interesting optics and microwave applications.