The Nobel prize in physics 2016 focused on topological states of matter in quantum materials whose paramount feature is exotic and robust surface states. Later it has been realised that a new type of exotic states can in principle occur at (lower-dimensional) corners and hinges. In the article “Corner states of light in photonic waveguides”, Ashraf El Hassan, Flore K. Kunst, Alexander Moritz, Guillermo Andler, Emil J. Bergholtz and Mohamed Bourennane at Fysikum have succeeded in creating such states — not in complex quantum materials, but rather in waveguides inscribed in glas using lasers. In these relatively simple and controllable systems, it is not electrons but visible light that form robust corner states. While this is mainly to be considered as pure basic science where the main novelty lies in realising abstract theoretical ideas in experiments, the simple and flexible implementation hints at intriguing possibilities in terms technological applications such as robust information transfer.   

The full study is published here: Corner states of light in photonic waveguides
(See also News & Views at Topological lattices lit at the corners )

Contact information
Emil Bergholtz, Wallenberg Academy Fellow;
Mohamed Bourennane professor;