Orsay free electron laser activities on the storage rings ACO and super-ACO

The main results obtained on the free electron laser and on optical harmonic generation with the storage ring ACO at Orsay in France are reviewed. A specific magnetic device, generally called an undulator, allows one to collect coherent light. In the free electron laser case, the undulator radiation is stored and amplified in an optical cavity. Tunable light was obtained in the visible range. For optical harmonic generation, external laser light is emitted in the undulator area, generating coherent harmonic radiation. Experimentally, 350, 177 and 107 nm wavelengths were obtained with a Nd-YAG laser. New experiments are planned with the Super-ACO storage ring, and preliminary experiments with the optical klystron are given.