We have seen the light 鈥 as it flies through the air in three dimensions Screengrab via Kazuhiro Morimoto
An ultra-fast camera has captured a video of light as it bounces between mirrors.
Although light isn鈥檛 normally visible in flight, some photons from a laser pulse will scatter off particles in the air and can be picked up by a camera. Using these photons to recreate the pulse鈥檚 trajectory is difficult, because by the time they reach the camera, the pulse has moved to a new location.
Edoardo Charbon at the Swiss Federal Institute of Technology in Lausanne and his colleagues used a聽camera with a shutter speed of聽about a trillionth of a second to聽take聽pictures and video of a laser聽beam following a 3D path.
Advertisement
Knowing exactly how long the pulse took to get to the camera, along with the pulse鈥檚 trajectory in a flat plane, allowed a machine learning algorithm to reconstruct the entire 3D path of the burst of light.
This could be useful in chemistry, says Marty Baylor at Carleton College in Minnesota. 鈥淵ou could watch light interacting with a molecule in real time鈥, giving a more detailed understanding of certain chemical reactions, she says.
A similar method could also be used to see around obstacles, says Charbon. If you bounced a laser pulse off a wall, then off an obscured object around a corner and back off the wall again before capturing it, the algorithm could potentially reconstruct an image.
Reference:
Topics:
