Manipulating Light at the Nanoscale

A large international collaboration of researchers led by the Fritz Haber Institute, the Paul Drude Institute, and the University of Iowa proposes a new way to control how light moves through materials at extremely small scales. This approach could lead to better sensors, faster communications, and smaller optical devices. 

An international collaboration combining theory and experiments, led by scientists from the Physical Chemistry and Theory Department of our institute together with researchers from the Paul Drude Institute and the University of Iowa, has demonstrated a new strategy to control light at extremely small scales. The team focused on special waves called phonon polaritons, which form when light interacts with vibrations in a crystal. These waves can be confined to tiny spaces and guided along precise directions, making them promising for future optical technologies such as sensors, waveguides, and on-chip devices.

Until now, the frequencies of these waves were largely fixed by the material itself. The new study shows that swapping in a heavier form of oxygen in a 3D crystal called β-gallium oxide shifts the polariton frequencies without affecting the material’s behavior. 

“Essentially one obtains the same crystal, just a little heavier, but with remarkably different optical properties”, says Giulia Carini, one of the leading authors of this study.

Accordingly, this simple change allows researchers to guide light in ways that were not possible before, providing low-loss, flexible control of light at the nanoscale. 
The discovery opens the door to smaller, more efficient optical and electronic devices and could pave the way for next-generation nanophotonic and optoelectronic technologies.