You’re almost certainly familiar with the principle of shooting slow-motion video: the more frames you record per second of filming, the longer it runs (and therefore the slower it is) when you play it back.
While we’ve been seeing a host of impressive slow-mo cameras over the past few years, a team of researchers at Washington University in St. Louis may have just beaten the rest of the pack — courtesy of a camera able to shoot rapidly enough that it can record a light sonic boom in real time.
“While a typical smart phone captures movies at 30 frames per second, our camera is capable of recording at 100 billion frames per second,” Jinyang Liang, a postdoc research assistant at the university, told Digital Trends. “For the first time, it is possible to record light propagation in real time. While sonic booms can be recorded using light, the photonic counterparts were simply too fast to record with existing technologies. Our camera is a game changer.”
Being able to photograph these elusive light sonic booms allows researchers to conclusively answer questions about whether light produces conical wakes similar to regular sonic booms (it does!). Aside from the high-tech camera, the work involved firing pulses of green laser light — each one 7 trillionths of a second — down a tunnel filled with dry ice.
It’s fascinating work, which you can read about in the group’s published paper, but it’s most exciting because of the possibilities it presents. Being able to record light sonic booms (officially known as photonic Mach cones) in this way has several intriguing applications.
For instance, Cherenkov radiation, a variant of Mach cones, has been used in monitoring radiation doses: a use case you wouldn’t necessarily think a camera could be involved with. And Liang says that there’s another fascinating purpose it could lend itself to.
“One biomedical application our lab is interested in is to watch the ‘live traffic’ of brain signals, which are too fast to capture in real time by existing cameras,” he said. “Our university also plans to have our technology commercialized so more scientists can have access to our cameras.”
A camera speedy enough to watch our brain signals in action? Color us intrigued!
