Researchers at Brigham Young University in the US, have developed a method of creating 3D images that float in mid air.

The research group, which includes holography expert Dr Daniel Smalley, took inspiration from a scene in the original Star Wars film, where R2D2 projects a 3D image of Princess Leia.

Princess Leia’s famous projection – widely believed to be a hologram – is actually a volumetric image.

Holographic images are created by light scattered across 2D surfaces, and can only be seen when the viewer is looking directly at the surface. A volumetric image is a 3D rendering created when light is scattered across a number of different points spread across a 3D space, meaning it can be seen from every angle.

To create the images, the group developed a free-space volumetric display platform, based on photophoretic optical trapping.

“It’s like a 3D printer for light," said Smalley. "You’re actually printing an object in space with these little particles.

“We’re providing a method to make a volumetric image that can create the images we imagine we’ll have in the future."

The study was co-authored by Erich Nygaard, a BYU undergraduate. Explaining the process, he said that the method used a laser beam to trap particles in the formation of images. "When we trap the particle, we can steer the laser beam around to move the particle and create the image," he said.

So far the team have 3D-light-printed several small images including a Charmander from Pokémon, a butterfly, the university logo, a prism, rings that wrap around an arm, and even a lab-coated figure crouched in the same position as Princess Leia when her image first appears.

Volumetric imagery is currently being researched by groups outside of BYU, however Smalley’s team is the first to effectively utilise optical trapping and colour.