Waveguide Closeup (IMAGE) Duke University Caption This is a closer look at the new optical waveguide device featuring a zoomed-in view of the fabricated photonic crystal topological insulator. Credit Natasha Litchinitser, Duke University Usage Restrictions None License Licensed 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.