Caltech device redirects light in less than a trillionth of a second

Caltech researchers have developed a device that redirects one light beam using another in 74 femtoseconds—about the time light takes to cross a human hair's width. The team, led by Harry Atwater, used optical meta-surfaces and the optical Kerr effect to achieve ultrafast photonic control, steering beams by up to 13 degrees without slowing light's speed.

Steering light with light is very challenging because light typically interacts very weakly with matter. Using optical meta-surfaces, we can up the interaction strength to make this possible with much higher efficiency.