An ultrahigh-fidelity 3D holographic display using scattering to homogenize the angular spectrum

Motion Hologram: Jointly optimized hologram generation and motion planning for photorealistic 3D displays via reinforcement learning

Holography is capable of rendering three-dimensional scenes with full-depth control and delivering transformative experiences across numerous domains, including virtual and augmented reality, education, and communication. However, traditional holography presents 3D scenes with unnatural defocus and severe speckles due to the limited space bandwidth product of the spatial light modulator (SLM). Here, we introduce Motion Hologram, a holographic technique that accurately portrays photorealistic and speckle-free 3D scenes. This technique leverages a single hologram and a learnable motion trajectory, which are jointly optimized within a deep reinforcement learning framework. Specifically, we experimentally demonstrated that the proposed technique could achieve a 4- to 5-dB PSNR improvement of focal stacks in comparison with traditional holography and could successfully depict speckle-free, high-fidelity, and full-color 3D displays using only a commercial SLM. We believe that the proposed method promises a prospective form of holographic displays that will offer immersive viewing experiences for audiences.

3D scattering-enabled vectorial holographic projection with a binary amplitude hologram

Empowered by wavefront shaping (WFS) techniques, scattering materials (SMs) hold significant potential in high-capacity, high-fidelity, and crosstalk-free 3D holographic projections. Here, we present an optimal accumulation algorithm (OAA) to generate binary amplitude holograms that enable simultaneous control of 3D intensity and polarization distributions through SMs. In particular, OAA is efficient for creating binary holograms since only addition and comparison operations are required. Using such a binary hologram, we demonstrate complete polarization control on four planes simultaneously, and an average degree of polarization over 95% is achieved. Moreover, a 3D holographic projection of polarization-multiplexed images on multiple planes is also presented with an average Pearson correlation coefficient over 0.80. By exploiting the rapid switching ability of a digital micromirror device, we further demonstrate dynamic 3D vectorial holographic projections with reconfigurable binary amplitude holograms. Our proposed approach offers a competitive way to generate holograms for 3D scattering-enabled vectorial holographic projections.

High-fidelity multi-channel optical information transmission through scattering media

High-fidelity optical information transmission through strongly scattering media is challenging, but is crucial for the applications such as the free-space optical communication in a haze or fog. Binarizing optical information can somehow suppress the disruptions caused by light scattering. However, this method gives a compromised communication throughput. Here, we propose high-fidelity multiplexing anti-scattering transmission (MAST). MAST encodes multiple bits into a complex-valued pattern, loads the complex-valued pattern to an optical field through modulation, and finally employs a scattering matrix-assisted retrieval technique to reconstruct the original information from the speckle patterns. In our demonstration, we multiplexed three channels and MAST achieved a high-fidelity transmission of 3072 (= 1024× 3) bits data per transmission and average transmission error as small as 0.06%.