Back in 2018, researchers from Brigham Young University demonstrated a device called an Optical Trap Display that used lasers to create free-floating holographic images that don’t need a display. That same team is now demonstrating a new technique that allows those holographic images to be animated: goodbye TVs, hello holodecks.
Most 3D holograms require a special screen to be displayed, and even then the 3D effect is limited to a small field of view. Images genuinely look like they exist in 3D space, but step to the side and suddenly you see nothing at all. The approach taken by the researchers at Brigham Young University is radically different. Screens are replaced by lasers: an invisible one that manipulates a tiny opaque particle floating in the air, and a visible one that illuminates the particle with different colours as it travels through a pre-defined path, creating what appears to a floating image to a human observer.
Unlike the restricted viewing angle of traditional holograms, an observer can see these free-floating Optical Trap Display images from any angle and can walk all the way around them without the 3D effect disappearing because the floating images are actually drawn in 3D space.
Three years of improving the technology used in the Optical Trap Displays has now allowed the BYU researchers to take the effect to the next step with animations that play out in front of an observer’s eyes in real-time. The team demonstrated the amazing effect with tiny recreations of Star Trek spaceships engaged in a mid-air photon torpedo battle (complete with simulated explosions that look like vector animations straight out of Tron) and even miniature versions of Obi-Wan and Darth Vader dueling with glowing lightsabers made from actual lasers.
The researchers have even come up with ways to track the movements of a real-life object and make the free-floating holograms appear to interact with its movements, like an animated stick figure character walking across a human finger. Using optical tricks like playing with perspective and parallax motions, the holograms could even be made to appear much larger than they really are when projected in front of a pair of eyes, so there are some potentially interesting applications when it comes to making viable smart glasses.
In their current form the holograms being generated by the Optical Trap Displays are very tiny, requiring cameras with macro lenses and even microscopes to see the effect in detail because, in order for a beam of light to manipulate a tiny floating particle, it has to be very tiny. But as the technology improves, several moving particles could be combined to increase the size of the effect. Does this mean Star Trek’s holodecks are right around the corner? Not quite, but the technology demonstrates that despite being science fiction, it’s not a completely outlandish and impossible idea.