Controlling light with light is a long-sought goal for computing and communication technologies. Achieving this capability would allow optical signals to be processed without converting them into electrical signals, potentially enabling faster and more energy-efficient devices. In recent years, researchers have begun exploring an unexpected platform for this purpose: soft matter.

Researchers from Germany, Japan and India, led by scientists from DESY and the Universities of Kiel and Hamburg, have found a way to collectively make molecules on a flat surface rotate by exposing them to light using ultrafast light pulses from DESY’s free-electron laser FLASH and a high-harmonic generation source. However, making those molecules dance is not the ultimate goal: this result could have an impact on next-generation quantum and energy materials for electronics, data storage and energy conversion.

Researchers from the University of Science and Technology of China have achieved a major breakthrough in optical clock technology, developing a strontium optical lattice clock with stability and uncertainty both surpassing the 10⁻¹⁹ level, meaning the clock would lose or gain less than one second over roughly 30 billion years.