Microhollow cathode discharge excimer light sources

Summary form only given. Microhollow Cathode discharges are non-equilibrium, high pressure, direct current discharges. By reducing the diameter of the cathode opening in a hollow cathode discharge geometry to values in the sub millimeter range we were able to operate discharges in argon and xenon in a direct current mode up to atmospheric pressure (Scoenbach et al., 1997). We have shown that these discharges are intense sources of xenon and argon excimer radiation peaking at wavelengths of 172 nm and 130 nm, respectively (El-Habachi et al., 1998). Spatially resolved measurements of the excimer source in xenon have been performed. The source was found to be cylindrical along the axis of the electrodes. Its radius increases with current and decreases with pressure. Stacking the discharges, operating them in series, holds the promise for the generation of a laser medium with sufficient length to provide the required threshold gain for a DC excimer laser. Experimental studies of the gain of the plasma column in microhollow cathode discharges are underway.