Spatial-temporal characteristics of the emission of a high-power XeCl laser with an unstable telescoping resonator

The emission characteristics of an XeCl laser with an active volume of 30 l were investigated experimentally as a function of the instability of the telescoping resonator. Optimal resonator extension ratios, M, are determined which provide for minimum divergence (M = 18) and maximum brightness (M = 8.5) in the far region. It is shown that the use of an unstable telescoping resonator leads to pulse modulation in the far region with a period that is a multiple of the resonator transit time; the modulation depth increases with M.