A 100 MW far-infrared free-electron laser driven by a 180 MeV RF-linac

The development of a 100 MW far-infrared free-electron laser oscillator is reported. By using a 180 MeV electron beam, this system will provide the high power and the rapid scanning of the broad wavelength range, 10–100 μm, to enhance the user programs. The intracavity power of several GWs will be used for Compton backscattering X- or γ-ray generation. To store such an intense radiation, the dynamics of the FEL oscillator with a coupling parameter μc⩽1, which is defined as the ratio of the slippage distance and the electron bunch length, was investigated experimentally on the operating mid-infrared system.