Beam profile measurements have been made as a function of time within the laser pulse and C2F5I pressure. Measurements indicate that the profile is determinied directly by the optical excitation volume, produced by the solar simulator, and that media distortion plays a minor role compared to the build up of quenching species during the lasing pulse.
Russell J. De Young, "Beam profile measurement of a solar-pumped iodine laser," Appl. Opt. 25, 3850-3854 (1986)