Optical beam-energy modulators

Four devices are discussed. In each of these, electromagnetic waves of wavelength /spl lambda/ (which may be in the optical range) are to be used to modulate the energy of extreme relativistic charged particle beams on a scale of /spl gsim//spl lambda//2. The devices are: (1) two-wave modulators; the well-known optical klystron is a special case and has been used in the past for energy modulation. The other three are proposed as appropriate alternatives, depending on the circumstances: (2) vacuum modulator; it is the simplest in construction, and its energy modulation amplitude is essentially the function of only the power carried by the wave (e.g., laser power) and not the geometry nor /spl lambda/; (3) Cherenkov modulator; and (4) resonator energy modulator. Their capabilities, including the energy modulation amplitude, and efficiency, are compared.