Nature Materials (IMAGE) Elhuyar Fundazioa Caption An international team has proposed a novel method that allows to widely extend this range of working frequencies of phonon polaritons in van der Waals materials. Credit (Source: University of Oviedo) Usage Restrictions (Source: University of Oviedo) 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.