Source of Large Groups of Photons (IMAGE) University of Warsaw, Faculty of Physics Caption The heart of the system to generate groups of photons is a glass cell filled with hot gas vapor. Illuminating the cell with a laser results in the emission of photons with a wavelength in the infrared spectrum range. Credit Source: UW Physics, Mateusz Mazelanik Usage Restrictions The image may only be used with following caption: The heart of the system to generate groups of photons is a glass cell filled with hot gas vapour. Illuminating the cell with a laser results in the emission of photons with a wavelength in the infrared spectrum range. (Source: UW Physics, Mateusz Mazelanik) 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.