A newly-developed ultra-thin material tricks the human eye into perceiving highly detailed 3D images without the need for special glasses.
For science fiction nerds of a certain intensity, the 3D projection hologram is an instantly recognizable genre trope. Think Princess Leia beamed from R2-D2 in Star Wars, or the Tony Stark’s virtual displays in Iron Man.
For optical engineers, the true freestanding hologram has been a kind of Holy Grail for decades. The idea is to create a three-dimensional virtual image, in thin air, which does not require any kind of solid projection surface. Engineers have developed small-scale prototypes and clever approximations, like virtual Tupac. But true hologram technology remains elusive.
Researchers in Australia announced this week a potential new angle of attack to the enduring challenge.
Australian and Chinese scientists have developed a material that’s being billed as the world’s thinnest hologram. One thousand times smaller than a human hair, the material manipulates light on the nano scale to produce 3D-holographic effects, and can be applied to the surface of standard electronic displays of TVs, tablets, or phones.
The specifics get complicated — if you’re comfortable with terms like optical microscopy and phase shift modulation, you can browse the paper itself, published today in the journal Nature Communications.
The new technique allows for the encoding of massive amounts of visual information into small devices and displays. By reducing individual projection elements to the nano scale, the technology can produce three-dimensional images without the need for 3D glasses.
To be clear, these images are not freestanding holograms in the literal sense. There is no discrete light field being projected above the display surface. Instead, the technology tricks the eye by manipulating light in the manner of standard flat holograms, like those novelty cards or that symbol on your credit card.
The difference is that the new nano-hologram system produces the phase shift effect at a much higher resolution, allowing for bigger and more detailed images that appear to pop up and off the screen. There’s no “there” there, but your eyes can’t tell the difference.
Lead researcher Min Gu of RMIT University said that, while there are still some technical hurdles to be overcomes, the new technique can indeed create hologram effects like the ones we’ve been chasing for years.
“You can see the holographic image at a certain angle range and you don’t have to look directly at the screen,” Gu said in an email. “If the pixel size of the hologram is smaller, the view angle of the reconstructed image will be larger.”
The RMIT research team, working with the Beijing Institute of Technology, concluded the research by producing individual holographic images as small as 25 nanometers. (A sheet of paper is about 100,000 nanometers thick.) When clustered together, these tiny holograms generate multiple phase shifts on different optical wavelengths.
“The hologram is recorded in our material point-by-point using a direct laser writing system,” Gu said. “Each of the points generates a phase shift that leads to the hologram effect.”
Gu said there is no telling when the nano-hologram technology will actually be incorporated into consumer devices.
“This depends on many factors, like solving technical problems and industry investment,” Gu said.
As to our abiding dream of Princess Leia holograms, Gu was unequivocal: “Freestanding images could be created like those in science fiction films.”