Researchers at Heriot-Watt University have achieved a world-first in photonics by using light to control the polarization of electromagnetic waves at ultra-fast speeds, demonstrated in a Nature Photonics study.

The work shows that time-varying systems, once mainly theoretical, are now practically feasible and could power future tools in medicine and next-generation quantum technologies.

The method allows the material to change as light travels through it, signaling a fundamental shift from static photonics to time-varying photonics.

An ultrathin aluminium zinc oxide film, normally transparent like glass, was driven by an engineered ultrafast light burst; a second light pulse then had its polarization dynamics programmed by the first.

The study focuses on all-optical polarization control in time-varying low-index films through plasma symmetry breaking, enabling complete, ultrafast control of light polarization for any state.

This all-optical approach relies entirely on light, with no electronic or moving mechanical parts, achieving changes roughly 10,000 times faster than current electronics and effects about 100,000 times stronger than previously observed.

Potential applications span advanced medical diagnostics and drug development, quantum technologies, secure communications, and quantum computing, where polarization carries information and dynamic material properties open new capabilities.

The work was conducted by researchers from Heriot-Watt’s Institute of Photonics and Quantum Sciences, in collaboration with Purdue University, the University of Brescia, and the University of L’Aquila.