The interaction between the electrons and the radiation in a free-electron laser leads to a shift and a spread of the electron velocity distribution. The electron dynamics of a two-element system are studied in the small signal region. It is found that the efficiency and gain can be increased through introduction of an adjustable drift distance between two identical wigglers.
© 1980 Optical Society of America
Chun-Ching Shih and Amnon Yariv, "Two-element free-electron lasers," Opt. Lett. 5, 76-78 (1980)