Metasurface Holograms for Holographic Imaging

As a revolutionary three-dimensional (3D) optical imaging technique, optical holography has attracted wide attention for its capability of recording both the amplitude and phase information of light scattered from objects. Holograms are designed to transform an incident wave into a desired arbitrary wavefront in the far field, which requires ultimate complex phase control in each hologram pixel. Conventional holograms shape the wavefront via the phase accumulation effect during the wave propagation through bulky optical elements, suffering issues of low-resolution imaging and high-order diffraction. Recently, metasurfaces, 2D metamaterials with ultrathin thickness, have emerged as an important platform to reproduce computer-generated holograms due to their advantages in manipulating light with well-controlled amplitude, phase, and polarization. In this article, the latest research progress in various types of metasurface holograms is reviewed from their design principles to versatile functional applications. At the end, more potential applications of metasurface holograms are discussed and some future research directions are also provided.