How a time cloak could change the past

Now, a new animation by Moti Fridman and his team at Cornell University, who have developed a technology that can hide superfast events, demonstrates how such a device would work. It shows how a stealthy ball can sneak by a laser beam thanks to a series of light tricks that mask an event over a specific period of time.

The demo shows how manipulating the laser beam creates an opportune time gap. Laser pulses, shown in red, break the signal beam, denoted in green, into a rainbow of different wavelengths that travel at different speeds. This change creates an opening in the beam where the ball can pass. The effect is then reversed with another pulse of light to make the change undetectable.

So far, the team has used the effect to edit out 15 picoseconds as a light beam passed through filters. However, the technique could be developed for a range of applications, for example to hide data moving through fiber optic cables to prevent eavesdropping.