Oscillator performance and energy extraction from a KrF laser pumped by a high-intensity relativistic electron beam

A laser cell with 21 of excitation volume was used to study the electron-beam pumped KrF laser system at excitation rates of 1.8- 7.0 MW/cm³. The system was optimized as an oscillator for various mixtures of Ar, Kr, and F2at total pressures of 1000 and 2500 torr. The resulting optimum conditions gave an intrinsic efficiency (laser energy out/electron-beam energy deposited) of 12 percent for the 1000 torr total pressure mixture with an output energy of 11 J/1. An efficiency of 10 percent with an output of 40 J/1 was obtained for the 2500 torr mixture. The system was then used as an amplifier to measure the extracted power as a function of input power for the two mixtures. The small-signal gain go, the nonsaturable absorption α, and the saturation intensity Iswere determined for the two mixtures. Analysis of the data gave g0= 16-18 percent/cm, percent/cm, and Is= 2 MW/cm²for the 1000 torr mixture and g0= 17-19 percent/cm, percent/cm, and MW/cm²for the 2500 torr mix.