Holograms capable of projecting multiple images in color and high definition without interference: this technological feat, called "metaholograms," could transform augmented and virtual reality (AR/VR) technologies. With these advancements, AR/VR screens will offer higher resolutions and wider viewing angles.
Diagram of a six-channel holographic image projection without crosstalk over a wide visible range by the metahologram. Each of the six independent images (e.g., uppercase letters with different colors shown in the diagram) can be selectively projected.
Metaholograms offer several advantages over traditional holograms: wider bandwidth, higher image resolution, broader viewing angle, and more compact size. However, their limited data capacity remained a major challenge, allowing only a few independent images to be projected, often with channel interference.
To solve this issue, researchers introduced an innovative k-space translation strategy, enabling a switch between "displayed" and "hidden" images. This approach uses polysilicon nanopillars to eliminate interference between image channels.
By utilizing properties such as polarization and angle, these metaholograms can project up to six unique high-definition images without interference. They can even project colored images through a two-channel version.
These advancements promise to significantly enhance AR/VR displays by enabling the projection of more complex and realistic scenes. They also offer potential applications in the field of image encryption, where information is encoded into multiple holographic channels for increased security.
(a) Diagram of the experimental setup for color imaging.
(b) Experimental results of the color metahologram. Two color holographic images ("lilac" and "rose") are selectively projected using guided red, green, and blue lights.
Credit: Zeyang Liu, Hao Gao, Taigao Ma, Vishva Ray, Niu Liu, Xinliang Zhang, L. Jay Guo, and Cheng Zhang
This research marks a significant step forward in developing high-performance metaholograms with greatly increased data handling capacity, paving the way for new possibilities in various fields.