Time Swapping - Slits in Time

A new diffracton study sends lasers through 'slits in time' in a novel take on the classic double slit experiment. (Image credit: Thomas Angus, Imperial College London)

In a first, scientists have shown that they can send light through "slits" in time.


The new experiment is a twist on a 220-year-old demonstration, in which light shines through two slits in a screen to create a unique diffraction pattern across space, where the peaks and troughs of the light wave add up or cancel out. In the new experiment, researchers created a similar pattern in time, essentially changing the color of an ultrabrief laser pulse.

The findings pave the way for advances in analog computers that manipulate data imprinted on beams of light instead of digital bits - it might even make such computers "learn" from the data. They also deepen our understanding of the fundamental nature of light and its interactions with materials.

For the new study, described April 3 in the journal Nature Physics(opens in new tab), the researchers used indium tin oxide (ITO), the material found in most phone screens. 

Scientists already knew ITO could change from transparent to reflective in response to light, but the researchers found it occurs much faster than previously thought, in less than 10 femtoseconds (10 millionths of a billionth of a second).

"This was a very big surprise and at the beginning it was something that we couldn’t explain," study lead author Riccardo Sapienza(opens in new tab), a physicist at the Imperial College London, told Live Science. 

Eventually, the researchers figured out why the reaction happened so fast by scrutinizing the theory of how the electrons in ITO respond to incident light. "But it took us a long time to understand it."  READ MORE...