Optical diagnostics for a ring resonator free-electron laser

Abstract

Overview of ExperimentBoeing's visible free-electron laser (FEL) program was proposed as a three-step process to demonstrate the feasibility of high average power FELs. In the first step a visible, concentric cavity, FEL oscillator was built and tested. It was a high peak power, but low average power device. In 1987 this experiment achieved the shortest wavelength radiation (0.50 rim) from any rfaccelerator-driven oscillator.' Sideband generation was demonstrated both in the 4% tapered wiggler and in the untapered wiggler. Measurements with the untapered wiggler indicated extraction efficiencies up to 0.25%, whereas extraction efficiencies of up to 0.75% were seen in the 4% tapered wiggler.2'3