Floating Holograms Coming to a Clinic Near You

Brian Owens

May 20, 2021


Airborne three-dimensional holograms are a staple of science fiction, from Princess Leia's cry for help in Star Wars to the holodeck on Star Trek. Now, Daniel Smalley, an electrical engineer at Brigham Young University, is making them a reality in a way that could allow healthcare workers to display the human anatomy in 3D to explain medical issues to people.

In much the same way that children write their names with sparklers in the air on the Fourth of July, Smalley is using lasers to draw pictures. Working with a team of engineers, he invented a laser system to generate screenless, free-floating images.

It works by trapping a tiny particle of black liquor — a waste product from the paper industry — in a bubble of light created by a laser beam that can be moved around in the air.

"We've essentially created a tractor beam that can drag a particle around in space," Smalley says. "You can put the particle anywhere you can focus the light." Using lasers in red, green, and blue, the engineers add color and move the beams rapidly through the air to draw pictures.

They first demonstrated the technology, which they call an optical-trap display, with animations of space battles between the Starship Enterprise and a Klingon ship.

But the system could have applications in medicine, Smalley suggests. Doctors could use it to plan complicated surgeries and medical students could use it for training.

A Look Inside the Human Body

Seeing the human body in real time could help people understand their anatomy and the medical care they need.

For surgeons planning complicated procedures, a high-resolution MRI with an optical-trap display could show, in three dimensions, the specific issues they are likely to encounter. Like a real-life game of Operation, surgical teams will be able to plan how to navigate delicate aspects of their upcoming procedures.

And for medical students in training, having a virtual cadaver to interact with will give them a close-up look at different structures simultaneously, such as the skeleton and circulatory system.

But for the electrical engineers designing this system, there have been drawbacks. Initially, they couldn't add perspective or a sense of depth to their images. And although traditional holograms are tied to a physical screen, they were providing clearer images than the screenless holograms.

"You can put a holographic display on a wall and create a window to another world," Smalley points out. "That was impossible for our display because it only created points of light. It was a major limitation."

So Smalley got back to work with engineer Wesley Rogers to see if they could create images with stronger backdrops and more perspective. Their visualizations could already be examined from any angle or vantage point, but could they take them to the next level by adding more depth?

With funding from the National Science Foundation, they figured out how to shift the image of a background as the viewer moves, which means that objects in the distance appear at their actual scale. Smalley likens it to a theater production, saying, "at first we were only making props; now we are making the backdrop too."

This new approach will have advantages over screen-based holograms. "With 3D images, everything is so visceral. You're not extracting information from a 2D image, so there is no translation needed in your mind," Smalley explains.

Brian Owens is a freelance science journalist who has filed for Nature, New Scientist, and the Lancet. He won a National Magazine Award for best news story for an article in CMAJ, the Canadian Medical Association Journal.

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