Camera Captures Speed of Llight

Scientists at M.I.T.’s Media Lab are using an ultrafast imaging system to capture light itself as it passes through liquids and objects, in effect snapping a picture in less than two-trillionths of a second. Using a heavily modified Streak Tube (which is normally used to intensify photons into electron streams), the team could snap a single image of a laser as it passed through a soda bottle. The pulses of laser light enter through the bottom and travel to the cap, generating a conical shock wave that bounces off the sides of the bottle as the bullet passes. The streak tube scans and captures light in much the same way a cathode ray tube emits and paints an image on the inside of a computer monitor. 

Each horizontal line is exposed for just 1.71 picoseconds. To create a movie of the event, the researchers record about 500 frames in just under a nanosecond, or a billionth of a second. Because each individual movie has a very narrow field of view, they repeat the process a number of times, scanning it vertically to build a complete scene that shows the beam moving from one end of the bottle, bouncing off the cap and then scattering back through the fluid. The system allows the naked eye to see information that has until now been rendered as data and charts.


source:www.engadget.com