Amplitude and Phase Discretization Influence on Performance of Complex Amplitude Metasurfaces

Complex amplitude holography can be applied to calculate complete electromagnetic field information in the holographic plane, including amplitude and phase, so as to achieve high-precision image reconstruction. Complex amplitude metasurfaces, as ultra-thin and ultra-flat electromagnetic wave regulation elements, have opened a new path for the physical implementation of holograms. However, due to coupling between meta-atoms and manufacturing tolerance, it is impractical to accurately encode holographic metasurfaces. The solution is to reduce the number of different meta-atoms by discretizing amplitude and phase on the holographic plane. Here, we analyze and compare the imaging quality of different complex amplitude holographic metasurfaces in various discretization strategies. Numerical results indicate that reasonable discretization process can simplify the metasurfaces design and achieve well-performing image reconstruction.