Power extraction study of an e-beam-pumped atmospheric pressure, Kr-rich KrF laser amplifier

Single-pass (50-cm) amplification characteristics of a short-pulse [65 ns full width half maximum (FWHM)] e-beam-pumped KrF laser amplifier with an atmospheric pressure Kr-rich and Kr/F₂ mixture were investigated theoretically for wide excitation rate from 0.1 to 2.0 MW/cm³. We have constructed a one-dimensional propagation amplifier model which considers the gain depletion and the saturated absorption spatially and temporally in the amplifying medium. With this numerical model, good agreement was obtained between the calculated result and the experiment. As a result of this theoretical study, extraction efficiencies of over 40% and power efficiencies of over 10% are obtainable at the highest output powers for all atmospheric mixtures containing 10%-99% Kr gas for excitation rates ranging from 0.5 to 2.0 MW/cm³ using a 30-ns (FWHM) input laser pulse, indicating that high efficiency power extraction from an atmospheric pressure KrF laser amplifier is achievable.