Steady-state pulses in a laser amplifier with a delayed swept gain.

The theory of steady states in a nonlinear swept-gain amplifier is considered. The amplifier is transit-time broadened, and the gain has a delayed boundary, i.e., the gain pulse moves at a velocity less than the velocity of light. The problem is a close analog to nonlinear propagation in the Stanford free-electron laser (FEL). The results are in qualitative agreement with both theory and experiment in the FEL.