Atoms inside of an optical cavity (IMAGE) JILA Caption Atoms inside of an optical cavity exchange their momentum states by "playing catch" with photons. As the atoms absorb photons from an applied laser, the whole cloud of atoms recoil rather than the individual atoms. Credit Steven Burrows/Rey, Thompson, and Holland Groups Usage Restrictions Usage is allowed but with proper citation 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.