Interferometric measurement of two-dimensional Xe and electron density distributions in XeCl laser discharges

A near-infrared, interferometric measurement of the density distribution of the electrons and excited xenon atoms has been performed at two discharge pumped, X-ray preionized XeCl lasers. The experimental results of one of these lasers are in good agreement with model calculations for the homogeneous phase. The electrons and excited states of xenon show a different behaviour in their spatial distributions at both lasers. In addition a region of inhomogeneities, which is identified as the hot-spot region, is been found near the cathode. Filamentation of the discharge can occur after a short time. The dimension of the hot-spot region depends on the preionization delay time. The same holds for the filamentation process, which in addition depends on the HCl partial pressure.