Visible free‐electron‐laser oscillator (constant and tapered wiggler)

The first linac‐based visible free‐electron‐laser oscillator was operated in February 1987 at a wavelength of 525 nm with and without a wiggler taper. Peak output power of 29 kW with a macropulse average power of 1.1 W was observed. The cavity dielectric mirrors were damaged at approximately 21 kW/cm2 of average intracavity power.