Parameters evolution of laser beams with quite general transverse intensity profile

A plane-parallel cavity with a Gaussian reflectivity mirror has been applied to a XeCl laser medium having a spatially variable gain distribution. The evolution of the beam parameters has been experimentally analyzed as a function of the number of round trips. It is shown that in this case of intensity profiles affected by the spatial and temporal properties of the active medium gain, a theory formerly developed for the beam-parameter evolution of Gaussian Schell-model beams provides a satisfactory description of experimental measurements for the first few round trips.