Surface Phonon Polaritons (image) University of California - San Diego Caption This image shows surface phonon polaritons launched by infrared light propagate across layers of hexagonal boron nitride, a van der Waals crystal. Credit Siyuan Dai Usage Restrictions For use in news reports about this finding. For other uses, contact firstname.lastname@example.org. 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.