Caltech Steers Light in 74 Femtoseconds, Deflecting Beams by Up to 13 Degrees

1 articles · Updated · New Atlas · Aug 20

Caltech researchers changed a light beam’s direction in 74 femtoseconds by using one light pulse to steer another, a speed far beyond conventional light-steering methods.
The method exploits the optical Kerr effect: an intense pump beam briefly changes a medium’s refractive index, letting a weaker probe beam emerge at a new angle.
Amorphous silicon on nanoscale metasurface pillars strengthened the normally weak light-matter interaction, enabling deflection angles of up to 13 degrees with higher efficiency.
Existing approaches typically rely on electronic changes in chips or liquid crystals and operate on picosecond-to-nanosecond timescales, making the new all-optical approach markedly faster.
The team said further improvements could push modulation below 74 femtoseconds, opening paths to faster computing, image processing beyond 1 billion images per second, and better mobile sensors.