Optical Force (1 of 3) (IMAGE) Aalto University Caption The optical force on atoms forms a mass density wave that propagates with light through the crystal. Credit Jyrki Hokkanen / CSC - IT Center for Science 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.