Visible free-electron-laser oscillator. Final report

The first visible linac free-electron-laser (FEL) oscillator was operated above threshold at the wavelength of 526 nm with and without a taper. Peak output power of 170 kW with a macropulse average power of 1.1 watts was observed. The cavity dielectric mirrors were damaged at approximately 140 kW/cm/sup 2/ of average power in the presence of UV from the FEL harmonics. The gain and efficiency were much less than predicted due to developed wiggler field errors.