Holographic displays are considered to be promising technologies for augmented and virtual reality devices. Using spatial light modulators (SLMs), they can directly modulate the wavefront of light. Through the modulation of the wavefront, they can provide observers three-dimensional imagery. However, they suffer from a large computation load, and it is important to overcome the disadvantage for the popularization of holographic display techniques. In this invited paper, we adopt a deep learning algorithm for the fast generation of computer-generated holograms (CGHs). We propose the deep neural network designed for the generation of complex holograms. The overall algorithm for the learning-based generation of CGHs using the network is introduced, and the training strategy is provided. The simulation and experimental results are demonstrated, and we verified the feasibility of using the deep learning algorithm for CGH computation.
Recent developments in ultra-high-definition (UHD) displays have a major impact on holographic displays as well as conventional display systems. A spatial light modulator (SLM) can reproduce hologram data through wavefront modulation of the incident light, and a holographic printer can record a high-quality hologram by sequentially recording a number of holograms reproduced by the SLM on a holographic material. As UHD (4K) resolution SLMs have been popularized, higher quality holograms can be reproduced compared to previous 2K resolution SLMs. When applied to the holographic printer, it is possible to manufacture holographic optical elements (HOEs) having a multifunctioning property and a wide field of view. In this paper, we introduce the holographic printer system using an amplitude UHD SLM and its applications. The holographic printer consists of optical systems to generate high-quality hologram from UHD SLM and mechanical systems to record the hologram on holographic material. The details of the total system are introduced. Furthermore, we introduce a holographic near-eye display system using UHD SLM and an image combiner HOE which is manufactured by the holographic printer.