'Floating 3D printing' brings sci-fi-style projections closer

'Optical trap display' projects graphics into the air, where they are visible from all angles We still don't have flying cars, brain-computer interfaces, or an artificial intelligence (AI) you can hold a conversation with, but one classic science-fiction technology is on our doorstep: true 3D displays which are capable of projecting an image into "thin air". A new paper in the journal Nature reports a breakthrough from a group of researchers at Brigham Young University in Utah: the first creation of a "free-space volumetric display", capable of reproducing full-colour graphics floating in the air, visible from all angles. The technology, dubbed the "optical trap display", works using a technique that sounds like it was ripped from the cinema screen. "You capture a particle in an invisible, or almost invisible'tractor beam'," explains the lead researcher, Daniel Smalley, "then you drag that around to every point of an image. When it's in the right place, you shoot it with red, green and blue lasers to make it illuminate, and build up an image point by point, dragging this cellulose particle around as you go."