Simulations on harmonic generation with the particle tracking code GPT

The feasibility of generating higher order harmonics from a free electron laser (FEL) amplifier with a tabletop system is investigated. The system is based on a small period undulator able to wiggle femtosecond short electron bunches over several tens of periods. Harmonic generation is obtained using a FEL system as a prebuncher for a 0.1 nC, 10 to 100 MeV electron bunch, which radiates in the second undulator tuned to a higher harmonic of the FEL. Simulations of the process, using the General Particle Tracer code with a new element that takes into account the radiation from particles, are presented.