Israeli scientist helps unlock new possibilities for light-based technologies

An Israeli researcher has contributed to developing a breakthrough optical technology that can steer and reshape beams of light in 74 femtoseconds - 74 quadrillionths of a second - potentially advancing optical computing, communications, imaging and sensing systems.

While controlling light is fundamental to technologies including cameras, sensors, and communication systems, the components that direct and shape light typically operate far more slowly than light itself. A new study presents a programmable ultra-thin optical surface capable of redirecting and reshaping a light beam at this unprecedented speed.

Dr. Lior Michaeli, head of the Meta-Optomechanics Laboratory at Tel Aviv University's Fleischman Faculty of Engineering, co-authored the research published in Nature Nanotechnology. The work was conducted at the California Institute of Technology under Prof. Harry Atwater and was led by Dr. Claudio Hail, now at the University of California, Berkeley.

The breakthrough centers on a metasurface - an ultra-thin material layer covered with precisely engineered nanoscale silicon structures smaller than light's wavelength. When illuminated by a short laser pulse, these structures temporarily alter their optical properties, enabling the surface to rapidly redirect and reshape another light beam without moving mirrors, lenses or mechanical components.

Laboratory experiments showed the device could steer beams by up to 13 degrees in either direction. By changing the spatial pattern of the illuminating pulse, researchers also reshaped the beam and created different light patterns, allowing the same device to perform different functions based on illumination.

"The key idea was to create a metasurface whose optical response is not fixed once it is fabricated," Hail said. "By changing the illumination pattern, we can reconfigure how the device steers and shapes light, and do so on an ultrafast timescale."

Atwater noted that controlling light with light has been historically challenging because light interacts weakly with most materials. "The metasurface enhances that interaction, allowing a very small and very fast material response to produce a useful change in the outgoing beam."

Michaeli highlighted the achievement of translating theory into practice: "For me, the most exciting aspect is seeing an idea that had been with us for years become an experimental reality. We had to design the metasurface so that it would amplify the effect enough not only to measure it, but to use it to steer and shape light."

The device has no moving parts and returns to its original state once the pulse passes. Faster, programmable optical control could eventually reduce the need to convert optical signals to electrical signals for processing, enabling more information processing directly with light.