Science //

Femto photography: faster than the speed of light

Ramesh Raskar’s new camera will light up your life, writes Rafi Alam

MIT’s Media Lab has developed a method of taking pictures of light passing through objects Source:
MIT’s Media Lab has developed a method of taking pictures of light passing through objects Source:

Science regularly employs cameras for some of its most weird and wonderful discoveries. Quantum physics, CERN and the Higgs Boson, and our research into space would have been impossible without them. They capture discreet, functionally invisible data that scientists then analyse to uncover new information about our universe.

But these aren’t your regular cameras.

The camera that captured the Higgs Boson, for instance, took images at 40 million frames per second. This was necessary to film the creation of the elusive particle, moving at speeds far beyond the extent of human sight. But while this number sounds impressive, a new invention by Ramesh Raskar and his team at MIT achieves a technical aptitude of a trillion frames per second.

It can, as he demonstrated at a TED event, capture the movement of light.

Science aficionados are likely aware that light is made up of photons, miniscule particles smaller than their subatomic counterparts, that exist as ‘packets’ that explode upon contact with matter. These explosions send out waves that illuminate its immediate surroundings.

Raskar’s camera technology, known as ‘femto’ photography (a femtosecond being 10-15 of a second, the speed at which the camera follows), captures light moving through various objects, such as a bottle, showing us the progression of luminosity. He highlights its possibilities for ‘scientific art’ by giving us examples of photos taken by the camera.

The scientific potential is more than just its aesthetic value. Femto photography can teach us more about the way light works. The characteristics of light are the subject of furious investigation in modern physics. It was only recently that the idea that light could be ‘slowing down’, and could be slowed down by humans, was uncovered. The nature of light as both a wave and a particle is also a field of study. And as quantum mechanics – that ethereal and esoteric science – becomes more important in computer technology, scientists will need to have access to devices that can record light in its various stages.

Raskar makes this evident when he shows an image of the waves of light moving away from the viewer, something that shouldn’t occur. He explains that this phenomena is due to the camera capturing a minute reversal of time in the photograph. Just some food for thought.

Another possibility of femto photography may be more astonishing to the average layperson. Raskar, along with, created CGI demonstrations of how the camera can be used to peek around corners. The demonstration has a camera pointed towards an open door, to the left of which is a mannequin hidden behind a wall. The camera sends out beams of light to the door, which then explode, hit the mannequin, explode again, hit the door, explode again, and hit the camera. A minute amount of light particles will actually make it back, and so the camera will do this multiple times, until – through an algorithm that uses the time taken for the particle to come back and the speed of time – the status of the object is created by calculating its distance and angle.

And, as Raskar shows, this forms a very similar image.

While this may sound complicated and long winded, the speed of light means this entire process takes only a few seconds in real time. Soon we may see the military using it to see around corners; later, as Raskar noted, you could use it check the state of objects, including how ripe a tomato is.

Femto photography will be integral to science is the upcoming decades. Despite its prominence in theoretical literature, light is one of the final frontiers of scientific discovery. Its usefulness for physicists is matched only by its functionality in practical applications.

Fortunately, the future for femto photography is looking bright, as Raskar has confirmed that this technology will be made open source for budding developers to use for their pleasure.

Rafi Alam is on Twitter: