Researchers at Brigham Young University have developed a technique to create full 3D moving images in a volumetric display in free space.
“We refer to this colloquially as the Princess Leia project,” said BYU electrical and computer engineering professor and holography expert Daniel Smalley. "The image of Princess Leia [from the fim Star Wars] is not what people think it is: It’s not a hologram. A 3D image that floats in air, that you can walk all around and see from every angle, is actually called a volumetric image."
The free-space volumetric display platform can be viewed from any angle, unlike a hologram, and is based on photophoretic optical trapping for full-colour, aerial volumetric images with 10-micron image points by persistence of vision.
This uses infrared laser beams to trap a single particle of cellulose and heat it evenly. That allows researchers to push and pull the cellulose around. A second set of lasers projects visible light (red, green and blue) onto the particle, illuminating it as it moves through space. Persistence of vision in humans allows the particle to appear as a solid line.
“In simple terms, we’re using a laser beam to trap a particle, and then we can steer the laser beam around to move the particle and create the image,” said undergrad coauthor Erich Nygaard.
“This display is like a 3D printer for light,” said Smalley. “You’re actually printing an object in space with these little particles.”
So far Smalley and his student researchers have 3D-light-printed several tiny images: a butterfly, a prism, the stretch-Y BYU logo, rings that wrap around an arm and an individual in a lab coat crouched in a position similar to Princess Leia.
“We’re providing a method to make a volumetric image that can create the images we imagine we’ll have in the future,” said Smalley.