Theoretical and experimental determination of single round-trip beam parameters in a Xe–Cl laser

The evolution of the main parameters (spot size, radius of curvature, and far-field divergence) of the beam provided by a high-gain, short-pulse Xe–Cl laser equipped with a plane-parallel Gaussian resonator has been investigated both theoretically and experimentally as a function of the number of round trips. It is shown that a theoretical analysis, formerly developed to study the growth of coherence of a Schell–Gauss model beam propagating through a periodic sequence of Gaussian apertures, provides a satisfactory description of the temporal evolution of the Xe–Cl laser beam. A good agreement between theoretical and experimental data has been found.