Influence of pumping inhomogeneity and amplified spontaneous emission on the characteristics of a large-aperture XeCl amplifier

Three-dimensional calculations in Cartesian coordinates are made for a double-pass XeCl amplifier having a volume of 1 X 1 X 3 m at p = 1 atm (Ar:He:HCl = 700:60:1 mixture). A complete model of the processes in the active medium is used. The Monte Carlo method is used to calculate the volume distribution of the density of the energy delivered by counterpropagating electron beams (J = 20 A/cm², ε_e = 0.4–0.5 MeV) at right angles to the optical flux. The influence of the parasitic amplified spontaneous radiation on the amplifier efficiency is studied. Calculations are made of the distribution of the output radiation in the far-field zone. These calculations allow for distortions of the wavefront due to anomalous dispersion and refraction by electrons for various types of pumping inhomogeneity.