SHORT-PULSE HIGH-INTENSITY EXCIMER LASERS - A POWERFUL TOOL FOR THE GENERATION OF COHERENT VUV AND XUV RADIATION

Different approaches for the generation of coherent VUV and XUV radiat ion with a 400 fs KrF excimer-laser system are studied. In nonlinear o ptical experiments it is shown that four-wave difference-frequency mix ing in Xe, using a near two-photon resonance with the KrF laser radiat ion, is well suited for the generation of tunable VUV radiation in the range 130-200 nm. Conversion efficiencies of 2% and output energies u p to 260 mu J have been demonstrated. Further prospects to achieve mJ energies are discussed. Using this VUV source and the KrF laser, power ful XUV radiation can be generated by different low-order frequency mi xing processes. In first experiments on this subject, direct frequency tripling of the KrF laser pulse has resulted in 14 mu J XUV radiation at 83 nm.For the realization of soft-X-ray lasers, specific advantage s of short-pulse KrF drivers are discussed. Novel scenarios based on a hybrid KrF/Ti:sapphire laser system and multiphoton resonant excitati on are considered.