Photonic waveguide (IMAGE) Technical University of Denmark Caption The figure shows a scanning electron microscope image of one of the photonic waveguides studied by the DTU researchers. The waveguide is formed at the edge between two photonic topological insulators (blue and red) which are realized in nanoscale silicon membranes. It has been predicted that light propagating in such topological waveguides is immune to backscattering on structural defects, but this was never investigated experimentally. For the first time, the DTU team checked this in an experiment and found the opposite: strong backscattering. Credit: C. A. Rosiek. Credit Credit: C. A. Rosiek. Usage Restrictions Please credit C.A. Rosiek. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.