Want to capture light in slow motion – Femto photography!!

Imagine talking to a photon emitted by a laser and providing you vital information. A photon telling its story to you – where it had been travelling, where it was hit, how it bounced back and its journey back to the receiving device. Every tiny bit of information will be useful. We have cameras that work thousands of frames per seconds. Ever imagined a camera that can capture the light travel in slow motion. When I say slow motion – in millimeters of change which is around 0.6 mm per second. It would be a movie of a photon hardly 5 seconds in real time motion that would go on for a year to complete its picture in slow motion. Taking images of light in a trillionth of a second which is 1 × 10^-15. Why is such an image necessary and what would be its future applications of such assiduous studies of flight of light?



Well, such cameras can be used in cars that might avoid collisions at the turns, new techniques of finding people trapped in the fire and also in medical operations where we can find artery blocks through emission of light and finding its trajectory. The imaging is still in the initial stages and is carried out by a group of professors from MIT who are led by Ramesh Raskar, head of Media Labs Camera Culture from MIT.  The concept of Femto photography was initiated by the famous photograph of a bullet piercing an apple by Harold Eugene Edgerton. The photograph was taken in 1964 through electronic flash that could capture motions in the time of millionth of a second.

Femtosecond means 10^-15 of a second. Femto-photography can literally go beyond millions and take one trillion frames per second. A light travelling from a source to destination takes place in less than a nanosecond. Light travels one foot in a nanosecond. But if we can reduce it to 10 billion times slower, then we can see the movie of light travelling through the same distance that would take a year to watch. We can also image an object which is around the corners by sending millions of light signals which are of short exposure that would hit the doors, and these signals would reflect from the object which is around the corner. By proper synchronization and collecting huge amounts of data received by the Femto camera we would be able to recreate the image by the received photons.  We would be able to see the world at the speed of light.



As a new technology is come to life, along with it comes factors limiting its use. The Femto camera is not a normal camera which you could purchase on eBay, but it’s a special one known as streak camera that captures horizontal line on the scene at a fixed height with two picosecond time resolution. The images produced are 2D images one with respect with the time and other with respect with space. It may cost around 25 million dollars. Another possibility is the effect of laser lights if used in the cardioscope. But imagine we would be able to watch real-time light slowed down to a few billions of seconds and watch its characteristics and it’s possible mysteries that can be unveiled and probably unlock a new discovery.

Watch the example of Femto photography by Ramesh Raskar on TED Talks

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