A team of researchers from Princeton University has started doing some very strange things with light. Instead of letting it zip by at incredibly high speed, they're stopping it dead: freezing it into crystal.


Crucially, they're not shining light through crystal; rather, they making light into crystal. It's a process that involves fixing the particles of light known as photons in a single spot, freezing them permanently in one place. It's never been done before, and it could help develop new exotic materials with weird and wonderful properties.

So what did they actually do? First, they built a structure made of superconducting materials, which contained 100 billion atoms engineered to act as a kind of artificial atom. Then, they placed the artificial atom close to a superconducting wire containing photons.


The rules of quantum mechanics mean that the photons on the wire then inherited some of the properties of the atom. So, while photons don't usually interact with each other, in this case they became slightly linked—and began interacting with each other, a bit like particles. Darius Sadri, one of the researchers, explains to Science Blog what that made possible:

"We have used this blending together of the photons and the atom to artificially devise strong interactions among the photons. These interactions then lead to completely new collective behavior for light – akin to the phases of matter, like liquids and crystals, studied in condensed matter physics."

The result: a kind of solid light, where photons are sat frozen in space. The devices—and the crystals—are currently incredibly small right bow. But the hope is that the system will grown, and over time the researchers will be able to make other interesting materials, like superfluids and and insulators, all out of light. Quite what they'll be used for remains unclear—but it might just be the strangest new material you'll see. [Physical Review X via Science Blog]