Think of it as the ultimate slow-motion movie camera. Researchers at M.I.T. have developed an imaging system so fast it can trace the motion of pulses of light as they travel through liquids and solids. To put it into perspective, writes John Markoff in The New York Times, “If a bullet were tracked in the same fashion moving through the same fluid, the resulting movie would last three years.”
We have built an imaging solution that allows us to visualize the propagation of light. The effective exposure time of each frame is two trillionths of a second and the resultant visualization depicts the movement of light at roughly half a trillion frames per second. Direct recording of reflected or scattered light at such a frame rate with sufficient brightness is nearly impossible. We use an indirect ‘stroboscopic’ method that records millions of repeated measurements by careful scanning in time and viewpoints. Then we rearrange the data to create a ‘movie’ of a nanosecond long event.