The gain and efficiency improvement of a free-electron laser by an optical klystron configuration

The feasibility of a high-grain amplifier in an optical klystron configuration at wavelengths of 1-2 mm was investigated using a computer simulation. A one-dimensional single-particle model for the free-electron laser (FEL) interaction was used in the numerical studies. It was found that for a three-cavity optical klystron gain of at least 30 dB and relatively high efficiency is possible for relatively modest electron-beam parameters (V>