Meta-hologram for three-dimensional display in terahertz waveband

Meta-hologram is a hologram constructed with metasurface which is composed of subwavelength optical antennas. Most of the meta-holograms are phase-only modulated. The phase distributions in these holograms are obtained by phase retrieval algorithm, which requires a lot of time and computing resources. Here, we design and demonstrate a meta-hologram with both phase and amplitude modulations for three-dimensional (3D) display by a simple method of inverse Fresnel-Kirchhoff integral in terahertz (THz) waveband. In this work, a meta-hologram with 8-level phase and 8-level amplitude modulations is realized by 64 subwavelength metallic C-shaped slot antennas. A THz holographic imaging system is utilized to detect the reconstructed images on different z planes along the direction of THz wave propagation. After the meta-hologram, three letters are clearly reconstructed in the preset positions. The meta-hologram with both phase and amplitude modulations can offer great potential applications in cartoon, virtual reality, and other applications bases on 3D figures display.