Evaluation of Compact FELS Operating at 0.4 Micron Wavelength

摘要

The behavior of Compact Free Electron Lasers is analyzed from a analytical andnumerical point of view. The operating principles of the Compact FEL are reviewed with specific reference to electron dynamics, the gain mechanism, evolution of the optical field, and the generation of harmonics. Size and complexity of FEL systems can be substantially reduced by using micro-undulators that employ harmonics to reach optical wavelengths with low electron beam energy. The use of harmonics at short wavelengths improves the undulator design with longer periods that would be easier to fabricate. Numerical computer codes describing FEL physics are utilized to explore the advantages of using harmonics. Five methods that model various combinations of FEL physical effects with different levels of sophistication are used to obtain results of gain calculations. The plots show gain degradation due to energy spread and strong field saturation effects. An analysis of beam quality is used to arrive at new electron beam size limits that simplify gain analysis for all undulator designs.