Degree of variation in the pattern of radiation amplified by a XeCl laser system

The radiation divergence is measured upon amplification of a beam 1.5 — 150 mm in diameter. The radiation wave front with a spatially nonuniform intensity distribution caused by diffraction from a small-diameter aperture is shown to experience significant changes upon amplification in the active medium. The amplifier active medium excited by an electron beam permits amplification of the radiation with a divergence ~10 μrad without introducing appreciable distortions. In the transportation and the amplification of a beam more than 75 mm in diameter, the main distortions of the wave front arise from turbulent air flows and the aberrations of the optical elements.