Effect of detuning caused by wavelength stabilization feedback on free-electron laser

In this paper, the modified 1-D time-dependent free electron laser (FEL) code is used to simulate the wavelength stabilization feedback system of a high average power FEL based on the parameters of Jefferson Lab's Demo-IR FEL facility. In the simulation, the distribution function of the electron is assumed to be Gaussian and there are 16 electrons in each longitude grid in the 1-D FEL code, the energy spread of the elctrons is ignored. The equivalent detuning caused by the electron energy changing has strong effects on the whole system of FEL. To some extent, it would destroy the interaction between the laser field and electrons, reduce the gain, even cause malfunction of the FEL. Therefore, this paper gives out a scheme to avoid the devastating influence, which shows it is feasible and ef