"Fairy Lights": Floating, Responsive 3D Holograms

Yes, holograms are a thing now.

Haven’t we had those for a while, you might ask? I seem to remember CNN going all-out during the 2008 election-coverage arms race when it beamed correspondent Jessica Yellin into Wolf Blitzer’s Situation Room.

And for that matter, didn’t Coachella holographically resurrect Tupac Shakur in 2012?

Well, no. According to CBC News, CNN filmed Yellin from 35 angles and superimposed the composite image onto the footage. Wolf himself saw nothing but thin air, so CNN’s achievement boils down to making the green screen effect a bit niftier and orders of magnitude more expensive (though admittedly I don’t have actual figures).

Coachella, meanwhile, used a technique known as “Pepper’s Ghost,” named after 19th-century illusionist John Pepper but known since at least the 16th century, when the treatise Magia Naturalis described the technique—in Latin. Coachella’s organizers did, however, succeed in spending perhaps $400,000 on CGI and making a few hip-hop fans squirm at the treatment of a great artist’s memory.

“Fairy lights”

Now we have something altogether different: tangible, aerial, volumetric graphics, which we’re apparently stuck calling “fairy lights.” Researchers at the University of Tsukuba, Utsunomiya University, the Nagoya Institute of Technology and the University of Tokyo have developed a technology that uses femtosecond lasers to ionize air molecules and thus create crackling, photon-emitting pockets of plasma. These lights, or “voxels,” can be arranged in mid-air to create moving, floating, interactive images.

Images courtesy of the University of Tsukuba’s Digital Nature Group.

“Fairy lights” overcome the limitations of quasi-holograms and Victorian parlor tricks. Since the ionized molecules themselves comprise the image, they do not need an additional medium to be projected onto: no glass, smoke or water vapor required. (They cannot exist in a complete vacuum, however: air, water or a fluorescent solution will do.) And because the technology can project three-dimensional images, these can be viewed from any angle.

The most amazing thing is that these lights are interactive. Not only can you can touch them; you can feel them and actually control them. A video (see below) released by the research team shows a hologram responding to the touch of a finger: a tiny image of a heart “breaks,” splitting into two segments; a box checks itself; the word “LOVE” becomes “HATE.” In effect, they’ve conjured little floating buttons out of thin air.


Now for the caveats. Safety is an issue. The sensation you get from touching a femtosecond laser-generated image is in fact super-hot plasma obliterating a tiny bit of tissue. Researchers insist this isn’t a big deal, because the lasers shut off after 1/60 of a second, much less than the two seconds which are needed to cause any real damage. As for the eyes, the team recommends wearing protective glasses.

Also, for the time being, the “fairy lights” recall Henry Ford’s famous quip about the Model T: any color you like, so long as it’s black. Except in this case, it’s a rather aggressive electric blue.

Then there is scalability. The researchers strike an optimistic note, but the fact is that their “fairy lights” are currently only a cubic centimeter in volume (with 5 cubic centimeters to flit around in), which was probably not an aesthetic choice. A predecessor to the new technology (see video below), created by Japanese firm Aerial Burton, projects much larger images through a similar ionization technique, but these are too dangerous to touch, as well as considerably louder.

So at the moment, we seem to be faced with a trade-off between large, dangerous displays and tiny, interactive ones. The researchers’ paper, however, says that while scalability through increased laser power is limited by safety concerns, it can theoretically be achieved, at least to some extent, by shortening the pulse width. Assuming resolution doesn’t suffer—another concern—the potential snazziness of this technology would make even those smug techno-cops from Minority Report blush.


The paper’s authors are coy about their fairy lights’ potential applications: “The detailed investigation of the characteristics of this plasma-generated haptic sensation with sophisticated spatiotemporal control is beyond the scope of this paper.”

Aerial Burton proposed that its larger, far more hazardous displays could serve as animated signage in emergency situations. The projector is small enough to be mounted on a car, allowing it to beam mobile warnings and instructions to a panicked citizenry.

But let’s say that Science manages to scale the fairy lights up without sacrificing safety or image resolution. Just for the sake of argument.

We could ditch physical screens for all but the most 2D of purposes. Rather than a sad, flat mess of tabs and windows, I’d be pulling the information for this article from a luxuriantly spacious, interactive 3D display (to be clear, I’m pulling the information for this paragraph and the next entirely from the realms of unscientific speculation, so take them for what they are). The z-axis would become a staple of physically manipulable Excel charts. Rather than emailing or G-chatting that gif to the next cubicle, you could physically toss it over: as it leaves the range of one voxel-generator, it’s picked up by the next.

Perhaps the crackling sound that for the moment is an irksome byproduct of the ionization reaction could be fine-tuned, along with the sensation of touching the voxels, yielding a textured, dulcet-toned interface. One in which dancing holograms of late great artists—and lengthy court battles with their estates—abound. Or perhaps none of that is feasible, even allowing for some generous what-ifs.

If you thought that was weird…

It may be that this research is only the tip of the iceberg. Yoichi Ochiai, who co-authored the “fairy lights” paper along with Kota Kumagai and four other colleagues, is also working on levitation machines. Using ultrasonic waves, “It is possible to make anything float, as long as the object is no more than 8 mm wide,” Ochiai says in an interview with Ignition.

Then there is technology to change the texture of real-world objects. The goal, apparently, is to stop simulating the real world through computers and start stimulating it: subtly, or not so subtly, having tangible effects on objects that lie on the “real” side of a fast-crumbling digital divide.

The author of the Ignition piece likened machines to plants in Ochiai’s scenario: essential, everywhere and mostly ignored. Groovy, futuristic utopia, you say? Well, here’s hoping. Digitized horrorscape awash in 0s and 1s? Don’t shoot the messenger.

The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.

The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.

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