Use of geometrical and physical optics to model free-electron lasers

Abstract

The design and analysis of free-electron laser (FEL) systems require accurately modeling both the propagation of the light beam through the resonator and the light beam’s interaction with the electron beam in the wiggler. In a previous work,1 a design algorithm was reported for determining the mirror parameters for a class of soft-x-ray grazing-incidence resonators for use in FEL systems. The unloaded resonator designs were analyzed by means of the diffraction-based optical design code GLAD and were shown to support stable Gaussian TEM00 modes. However, substantial distortion of an unloaded mode owing to the inclusion of the electron beam interaction could significantly affect the gain of the FEL.2 If the electron beam effects could be included in the FEL design algorithm, the resonator parameters could be adjusted to offset the distortions. We will present a preliminary report on an attempt to integrate a FEL electron-beam modeling code with the optical-design code GLAD in hopes of addressing some FEL design problems that each code alone is unable to handle.