Electron-beam excitation of gas lasers

Gas-laser-excitation with intense relativistic electron beams has gained popularity through many successful demonstrations of efficient conversion of electron-beam energy to laser energy. In some instances, electron-beam excitation of gas lasers has resulted in record laser energy and/or power, in higher efficiencies than has ever been obtained with any other excitation scheme, and in the discovery of lasers that have not been produced by any other excitation schemes. The feature of electron beams that make this laser excitation scheme so promising for use in high-power lasers is the high-power capability of electron beams. Three electron-beam geometrical configurations have been applied to gas-laser-excitation; electron-beam coaxial with the laser axis, electron-beam perpendicular to the laser axis, and radial convergent electron-beams. Measurements and comparisons with theory for these three geometries are given.