High compression ratio backward Raman conversion for high brightness excimer laser systems

A scheme of backward Raman pulse compression is proposed in which the backward first Stokes pulse is amplified under stationary conditions and the backward second Stokes under transient conditions by choosing an appropriate Raman medium. The compression factor and efficiency are improved by insertion of selective absorbers for the second Stokes component. The feasibility of such a scheme is demonstrated by an experiment in which a 249-nm UV pulse of 20-ns duration has been compressed into a 30-ps pulse with an power gain of 150 and energy conversion efficiency of 22%. Higher compression ratio and higher efficiency is expected under improved conditions.<
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