Researchers at the Adolphe Merkle Institute, the University of Fribourg, and New York University are investigating materials that could diffusely reflect all rays of incoming light, with long-term potential applications for example in light-based computing. Their work is being funded by a Swiss National Science Foundation (SNSF) Sinergia grant worth nearly CHF 2.8 million.

Clouds, milk, bones – all have one thing in common: they’re white because their constituents are sized and arranged in ways that efficiently reflect light. Prof. Ullrich Steiner (Adolphe Merkle Institute) and Prof. Frank Scheffold (Department of Physics, University of Fribourg) will attempt along with their colleague Prof. David Pine (New York University) to further our understanding of reflection by creating materials that integrate a phenomenon applicable to all kinds of waves but has yet to be observed experimentally for light in bulk materials. This phenomenon was described in the 1950s by the physicist and Nobel-prize winner Philip Anderson, who showed how an electron and its quantum wave can get arrested in place in a disordered medium. This so-called ‘Anderson localization’ was then proposed to be also applicable to light waves.

Anderson localization of light would in theory generate perfect reflection, and anything close would generate strong reflection already for very thin layers of a material. Scheffold has already shown with computer simulations that so-called disordered hyperuniform materials could reflect, with the right nano-architecture, nearly all incoming light. These structures, which are starting to be discovered in nature, fall somewhere between highly organized crystals and disordered materials. Researchers see several potential applications by creating a channel within the material. By doing so, light could not escape and be guided. This type of material could be used to develop ultrafast optical computers and devices, replacing certain types of electronics.

To create a material with strong localization characteristics, the NCCR researchers and their colleagues will develop nanoscale building blocks designed to form three-dimensional networks. The design of these blocks will allow them to tweak morphologies, from perfectly periodic lattices to almost randomly assembled networks. “This will allow us to explore the order-disorder parameter space in an unprecedented fashion, providing a new avenue in the study of light localization in disordered but highly correlated network morphologies,” explains Steiner. 

The research is funded by an SNSF Sinergia grant worth CHF 2.77 million over four years. The Sinergia program promotes the interdisciplinary collaboration of two to four research groups that propose breakthrough research.