How to Make Molecules Out of Light

One step closer to lightsabers becoming a real thing

A team of physicists from the University of Maryland and the National Institute of Standards and Technology have found a way to to bind light particles and form a kind of “two-atom molecule” that are held together by a still-murky strange type of force. This new breakthrough could pave the way for engineers to begin building actual objects out of light.

Yes, that’s right. Lightsabers. And probably some other really awesome and revolutionary technological applications. But let’s not lose sight of what’s important here.

Science-fiction dreams aside, this is still just very preliminary. In fact the technique they outline in the study (still unpublished, but will be soon in Physical Review Letters) is purely theoretical. But we’re not going to kill this dream just yet.

What the researchers have done is describe a plausible technique for how one could go about coupling photons together and have them stick to one together, like atoms do when they form molecules.

To call these bound particles of light “molecules” is something of a misnomer — they’re not actual molecules, but it’s a good metaphor nonetheless. Atoms bind by shared electrons back and forth, forging a kind of bond that keeps them close to another, but still a finite distance apart. In their paper, the researchers describe something very similar happening between to photons of light — bound together by a special force and traveling side by side through space.

University of Maryland physicist Alexey Gorshkov, one of the lead researchers on the project, said in a press release, “We’re learning how to build complex states of light that, in turn, can be built into more complex objects. This is the first time anyone has shown how to bind two photons a finite distance apart.”

When it comes to potential applications, Gorshkov and his colleagues are setting their sights a bit lower than lightsabers, touting the potential to create more sensitive types of light sensors, or use photons as information processors in computers.

I guess those things would be cool too.