KTP crystal (IMAGE) Optica Caption The researchers used periodic poling of the KTP crystal (shown here) to create the entangled photons. This allows the setup to be adapted to many other applications or wavelengths. Credit Carsten Pitsch, Fraunhofer IOSB Usage Restrictions None 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.