Stackable “Holobricks” Can Make Giant, Highly Realistic 3D Holographic Images

Researchers have developed a new method to display highly realistic holographic images using “holobricks,” which can be stacked together to create large-scale holograms. Photo credit: University of Cambridge

Researchers have developed a new method to display highly realistic holographic images using “holobricks,” which can be stacked together to create large-scale holograms.

Researchers from the University of Cambridge and Disney Research developed a holobrick proof-of-concept that can stitch holograms into one large seamless 3D image. This is the first time this technology has been demonstrated and opens the door to scalable 3D holographic displays. The results are published in the journal Light: Science & Applications.

As technology evolves, people want high-quality visual experiences, from high definition 2D television to 3D holographic augmented or virtual reality and large true 3D displays. These displays must support a significant flow of data: for a 2D Full HD display, the information data rate is about three gigabits per second (Gb/s), but a 3D display with the same resolution would require a rate of three terabit per second, the is not yet available.

Holographic displays can reconstruct high quality images for a true 3D visual experience. They are considered the ultimate display technology to connect the real and virtual worlds for immersive experiences.

Reconstructed holographic images of a toy train using holobricks (top) and original image captured by a camera (bottom). Photo credit: University of Cambridge

“Providing an adequate 3D experience with current technology is a major challenge,” said Professor Daping Chu from the Department of Engineering in Cambridge, who led the research. “Over the past decade, we have been working with our industry partners to develop holographic displays that enable the simultaneous realization of large dimensions and large fields of view, which must be matched with a hologram with a large optical information content.”

However, the information content of current hologram information is much greater than the display capabilities of current light engines known as spatial light modulators due to their limited spatial bandwidth product.

With 2D displays, it is common to tile small displays to form a large display. The approach examined here is similar, but for 3D displays, which has not been done before. “Stitching pieces of 3D images together is non-trivial because the final image needs to be seen as seamless from all angles and all depths,” said Chu, who is also director of the Center for Advanced Photonics and Electronics (CAPE). “Direct tiling of 3D images in real space is just not possible.”

To address this challenge, researchers developed the holobrick unit, which relies on coarsely integrated holographic displays for angularly tiled 3D images, a concept developed at CAPE with Disney Research about seven years ago.

Each of the holobricks uses a high information bandwidth spatial light modulator to convey information in conjunction with coarse-grain integrated optics to form angularly tiled 3D holograms with large viewing areas and fields of view.

Careful optical design ensures that the holographic stripe pattern fills the entire surface of the holobrick, allowing multiple holobricks to be seamlessly stacked to form a scalable, spatially tiled 3D holographic display that offers both a wide viewing angle and large size .

The proof-of-concept developed by the researchers consists of two seamlessly tiled holobricks. Each full-color brick is 1024 × 768 pixels with a 40° field of view and 24 frames per second to display tiled holograms for full 3D images.

“There are still many challenges to make ultra-large 3D displays with wide viewing angles, such as Like a 3D holographic wall,” Chu said. “We hope that this work can offer a promising avenue to solve this problem, based on the currently limited display capabilities of spatial light modulators.”

Reference: “Holobricks: Modular Grob Integral Holographic Displays” by Jin Li, Quinn Smithwick and Daping Chu, March 16, 2022 Light: Science & Applications.
DOI: 10.1038/s41377-022-00742-7