It’s true. It’s also true that you can make almost anything emit light if you pump enough power into it. But a group of researchers at Princeton not only made the oxygen in air emit light, they actually turned a piece of air into a laser.
Lasers are tricky to build, which is why the first lasers were only built 50 years ago, with painstaking machining of parts and alignment of mirrors. The air laser is still a laser, but it’s very different from the laser in your DVD player. The air laser has no mirrors, it has no container, and it doesn’t even have to be in a place where the researchers can physically reach it. The air laser does emit coherent light, though, and does emit light in a beam. And that’s really really cool!
Check out my news story at Optics & Photonics News about Making a laser out of air.