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Title: Spontaneous emission and gain in a waveguide free-electron laser

Journal Article · · IEEE Journal of Quantum Electronics (Institute of Electrical and Electronics Engineers); (United States)
DOI:https://doi.org/10.1109/3.104146· OSTI ID:5615530
;  [1]
  1. California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics

A free-electron laser enclosed in a waveguide of narrowly spaced parallel plates has been proposed as a compact, coherent source of far-infrared radiation. In this paper, the spontaneous emission and small-signal gain of such a device are analyzed. Maxwell's equations are solved for the fields of a relativistic electron beam passing through a linearly polarized undulator in the presence of a parallel-plane waveguide. The radiation intensity is resolved into its component waveguide modes for the fundamental frequency and for all harmonics. The intensity profile in a given harmonic mode is altered significantly when a parameter involving the undulator period, beam energy, and transverse dimension of the guide is such that the radiation group velocity is close to the electrons' axial velocity. The small-signal gain in the waveguide free-electron laser is calculated and related to the spontaneous emission. Near zero slip, the gain curve is significantly different from that of a free-space free-electron laser with the same parameters.

OSTI ID:
5615530
Journal Information:
IEEE Journal of Quantum Electronics (Institute of Electrical and Electronics Engineers); (United States), Vol. 27:12; ISSN 0018-9197
Country of Publication:
United States
Language:
English