Graphene produces a working 3D holographic display

A wide viewing angle, full-colour, holographic 3D display has been built using graphene-based materials.

20th Century Fox

Since "Help me, Obi Wan, you're my only hope" hit the big screens in 1977's "Star Wars," we've been dreaming of a full-3D holographic display. Mastering the technology isn't easy, though. We've seen multiple attempts that approximate a 3D display, like a 2D image visible from all directions, but the tech world wasn't quite up to the challenge of true 3D yet.

A new effort from Australian universities looks like it could be at least getting closer to the real deal, with materials made from the versatile carbon-based graphene as the key.

"While there is still work to be done, the prospect is of 3D images seemingly leaping out of the screens...without the need for cumbersome accessories such as 3D glasses," said Qin Li from Griffith University's School of Engineering, who conducted carbon-structure analysis for the research.

The graphene-enabled display created by a team of researchers from Griffith University and Swinburne University of Technology is based on Dennis Gabor's holographic method, which was developed in the 1940s and won Gabor the Nobel Prize in Physics in 1971.

The team has created a high-definition 3D holographic display with a wide viewing angle of up to 52 degrees, based on a digital holographic screen composed of small pixels that bend the light.

The technical details are a bit complicated. (Here they are explained in full by study co-authors Xianping Li and Min Gu of Swinburne University of Technology.)

hologram.jpg
The one-centimetre hologram has no upper limit on scalability. Li et al., Nature Communications

Essentially, the smaller the pixels used, the better the viewing angle of the resulting hologram created when light is bent by passing through the pixel.

To create the hologram, graphene oxide (a form of graphene mixed with oxygen) is treated with a process called photoreduction, using a rapidly pulsed laser to heat the graphene oxide. This creates the pixel that is capable of bending the light to produce a holographic image.

This, the team says, could one day revolutionise displays -- with the most obvious implications in mobile technology and wearable technology. It could also be used for holographic anti-counterfeit tags, security labels, and personal identification.

This makes sense for a first practical application, too: currently, the technology has only been used to produce holographic images up to one centimetre in size. Li and Gu note, however, that there is no limit to its scalability, thanks to graphene's mechanical strength.

Photoreduced graphene-oxide based displays could also theoretically be produced easily, given that the ability to modulate the refractive index of graphene oxides on multiple levels doesn't require solvents or post-processing, Li said.

"The use of graphene also relieves pressure on the world's dwindling supplies of indium, the metallic element that has been commonly used for electronic devices. Other technologies are being developed in this area, but photoreduced graphene oxide looks by far the most promising and most practical, particularly for wearable devices," she added.

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