Feedback control of cavity detuning in short-pulse free-electron lasers

Feedback control of cavity detuning length in a short-pulse free-electron laser oscillator system is suggested and numerical simulation results are presented. By changing the detuning length with reference to the position of the optical pulse at the end of every pass, the system operation is very stable, and very high power and comparably good spectral characteristics have been achieved. Feasibility of this scheme is also discussed.