1-D free-electron laser model without the slowly-varying approximation

A free-electron laser amplifier in the strong pump regime is studied without the slowly-varying envelope approximation (SVEA). A one-dimensional time-dependent code is used for numerical simulation of the evolution of the electron energy, the synchrotron phase of the electrons and the electric field of the laser. Electron-laser-facility-like parameters are used for the strong pump regime. Since the cooperation length is much smaller than the electron beam length, a steady-state solution is found to exist. Comparisons are made with the earlier results with the SVEA and the difference turns out to be negligible. It can be concluded that the SVEA can be applied to a wider class of problems than it sets out to be appropriate for.