THRESHOLD CONDITION AND SATURATION MECHANISMS FOR THE SUPER-ACO STORAGE-RING FREE-ELECTRON LASER

The Super-ACO free electron laser is currently operating in the visibl e spectral range; the laser also operated in the near UV. Threshold co nditions were determined for various configurations. These are in agre ement with the theoretical predictions based on the assumption that th e optical gain evolution is governed by the energy spread mechanism. D ynamical studies at a microtemporal (ps range) and macrotemporal (ms r ange) scale were performed for higher values of the gain over losses r anging from 1 to 3. Those experiments seem to indicate that the laser induced energy spread plays a minor role in the saturation mechanism. Dynamical evolution and saturation properties seem to be ruled by anot her mechanism, except when the laser is operating close to the thresho ld condition.