Three-dimensional propagation in free-electron laser amplifiers

We describe a numerical approach to three-dimensional simulation of free-electron lasers. We argue that neglecting the radial dependence of the wiggler vector potential is a good first approximation for the laser under study. We study the optical field in the paraxial approximation and ignore the electron-electron interaction. The optical field is propagated using a new implementation of well-known Fourier-Bessel techniques. Some preliminary amplifier results are presented.