Theoretical High-Efficiency Extraction Study Of A Short-Pulse Electron-Beam-Pumped Arf Laser Amplifier With Atmospheric Pressure Ar-Rich Mixtures

Single-pass (50 cm) amplifier performance of an atmospheric-pressure ArF laser pumped by a 65 ns full width at half maximum (FWHM) short-pulse electron beam (ebeam) was investigated theoretically for a wide range of excitation rates (0.1-2.0 MW/cm3). Atmospheric mixtures of Ne, Ar, and F2 (three mixtures of Ar = 40, 70 percent and Ne-free) were studied. We have constructed a kinetic numerical model of the ArF amplifier with a Ne buffer system. A one-dimensional propagation treatment considered the gain depletion and saturated absorption spatially and temporally along the optical axis. In this model the rate constants for electron quenching of ArF of 1.6 x 10_ 7, 1.9 x 10 _7, and 2.4 x 10 _7 cm3/s were used for Ar concentration of 40, 70 percent, and Ar/F2 mixture, respectively. With this amplifier model analysis, good agreement was obtained between theory and experiment. For the three mixtures, we calculated the extracted intensity using the optimum input intensities at each excitation rate. As a result, power efficiencies of over 10 percent were predicted at excitation rates ranging from 0.5 to 2.0 MW/cm3.