Figure 1. Design of the hologram metasurface.

(a) Schematic illustrating the calculation of the electric field distribution. The image plane is set at a given position (d = 6 mm), where the virtual object (“TJU”) is located. A plane wave incidence is assumed to transmit from the top and pass through the “TJU” aperture. The electric field of the “TJU” region is endowed with the same amplitude and phase so that the required electric field on the metasurface can be calculated by the diffraction theory. (b) Calculated five-level amplitude distribution of the electric field on the metasurface after normalization and discretization. (c) Calculated eight-level phase distribution of the electric field on the metasurface after discretization.