Caltech Develops Ultrafast Optical Chip for Light Beam Steering in 74 Femtoseconds

Caltech researchers have developed a groundbreaking chip that can redirect a beam of light in just 74 femtoseconds, which is 74 quadrillionths of a second. This technology uses a nanoscale silicon metasurface to modify the optical properties of a material, allowing one beam of light to steer another. The device eliminates the need for electrical signals, relying instead on the optical Kerr effect, where an intense light beam temporarily alters the refractive index of a material. The researchers created a meta-surface with nanoscale silicon pillars that amplify the small refractive index changes, enabling the redirection of light by up to 13 degrees in extremely short timeframes. The current speed limit of 74 femtoseconds is due to the laser pulse duration, not the material’s properties, suggesting potential for even faster applications in the future. This breakthrough could significantly advance photonic communications, computing, and sensing technologies, paving the way for next-generation devices that operate at unprecedented speeds. The research, published in Nature Nanotechnology, was led by Claudio Hail and Harry Atwater, with contributions from Lior Michaeli. The work was supported by various institutions including the Air Force Office of Scientific Research and the Kavli Nanoscience Institute at Caltech.