In this chapter, we have derived a design procedure and design criteria for free-electron lasers driven by electron beams from rf accelerators. We have also suggested a number of ways to reduce the oscillation-buildup time to reach saturation, or at least to reach a substantially high power level, as long as the short electron-beam pulse still lasts. One way to reduce this buildup time is to increase the single-path gain by using a waveguide for propagating the electromagnetic wave. This helps to reduce the FEL filling factor in cases when it would otherwise be small because of the wave diffraction. Another way is to inject a seed radiation wave into the cavity to provide an initial source radiation at a power level higher than the spontaneous emission. It is out of the scope of this chapter to derive the complete scaling laws of the FEL operating parameters and their optimization. Refs.
|Title of host publication||Infrared and Millimeter Waves|
|Number of pages||75|
|State||Published - 1984|