The guys at MIT Media Lab’s Camera Culture Group built an imaging solution that allows us to see propagation of light at an effective rate of one trillion frames per second. Direct recording of light at such a frame rate with sufficient brightness is nearly impossible. They used an indirect ‘stroboscopic’ method that combines millions of repeated measurements by careful scanning in time and viewpoints. This opens the possibility to replace ultrasound medical imaging with light propagation imaging, or whatever it’s name will be in the future.
The device has been developed by the MIT Media Lab’s Camera Culture group in collaboration with Bawendi Lab in the Department of Chemistry at MIT. A laser pulse that lasts less than one trillionth of a second is used as a flash and the light returning from the scene is collected by a camera at a rate equivalent to roughly 1 trillion frames per second. However, due to very short exposure times (roughly one trillionth of a second) and a narrow field of view of the camera, the video is captured over several minutes by repeated and periodic sampling.
More info at Raskar and Femtophoto