Though not synchotrons, one type of these devices 
Though not synchotrons, one type of these devices makes use of wigglers to accelerate electrons through a transverse magnetic field. In 2012, physicists used one of these devices to create particles which were successfully quantum teleported 150 kilometers away. These devices use optical pumping to bring the system to a short-lived state which decays into the most populated metastable state. That's called population inversion. These devices, which come in a free-electron type, are used to create a transmission hologram. They create coherent photons through stimulated emission. For 10 points, name these devices which can make a monochromatic beam of light.
Though not synchotrons, one type of these devices makes use of wigglers to accelerate electrons through a transverse magnetic field.