A professor of electrical engineering has used 3D-light printing volumetric displays to create “holograms” in thin air.
For three generations, small kids (and bigger kids) have watched in awe as a flickering image of a princess with massive hair buns and a white robe appealed to Obi-Wan Kenobi for help.
Now, thanks to Professor Daniel Smalley from Brigham Young University in the US, science fiction has become reality.
Called ‘The Princess Leia Project’, Smalley and his team have produced 3D images including a prism, butterfly and, of course, a person in a lab coat recreating Leia’s iconic scene.
They have also created more detailed images, including a 3D recreation of the Earth. All of these images are under 3 cm in width.
Holograms vs. 3D images
As Smalley explained, the 3D images in George Lucas’s space opera are not actually holograms, but a 3D-light printed, or volumetric, image.
What’s the difference? Holographic displays can only be seen on a two-dimensional plane, as they only scatter light in two directions to produce their image. Volumetric displays scatter light in three dimensions, and can be seen from any angle.
The research, published in Nature, explains that volumetric images are “the technology that most closely resembles the three-dimensional displays of popular fiction”, by creating luminous image points in space.
Simply put, these 3D images are created by trapping a particle in a laser beam, and steering the beam to trace the desired shape.
“You’re actually printing an object in space with these little particles,” Smalley said.
Science reported that larger and more detailed volumetric images could be printed more quickly by simultaneously trapping a plane of particles, rather than just one.
While Smalley isn’t the first to make a volumetric image, he has perfected the art of trapping particles and colouring them with lasers. Previous efforts used a rotating piece of glass to create the illusion of a 3D image, or beamed images onto dust or fog.
Rather than plan out epic space battles, the likelier use for this technology is in medical imaging or creating more accurate 3D maps.
“We’re providing a method to make a volumetric image that can create the images we imagine we’ll have in the future,” Smalley said.
A life’s ambition
Smalley has been working up to this achievement for many years. According to his biography on the university website, Smalley has been experimenting with machines since his youth, when he constructed an aluminium furnace from a metal bucket, sand and an old computer fan to recycle used cans as machine parts.
He later attended MIT, where he spent many years and higher degrees working to create the world’s first low-cost holographic video monitor, which used an aluminium interdigital transducer constructed on a $10 optical chip to scatter light along the chip’s microscopic waveguide channels to produce a hologramatic image. In 2015, Smalley and his MIT team made improvements to the colour-accuracy of the technology.
Smalley’s future ambitions include other concepts currently confined to books and screens, including brain probe technology and tractor beams.
For now, though, we can revel in the fact that our quest for 3D Star Wars-style holograms has been given a new hope.
