Superradiant short-pulse propagation in the free-electron laser oscillator

A numerical study has been made of free-electron laser oscillators in which the electron pulse length is comparable to the slippage. It is shown that the saturated optical pulse exhibits superradiant spiking behavior in which the peak power is proportional to the square of the current and the efficiency grows in proportion to the square root of the current. The authors investigate the optimum cavity detuning length necessary to beat the lethargy in the small-signal regime and to obtain maximum overlap between the optical and the electron pulses during every bounce of the radiation within the optical cavity