Improved conversion efficiency of XeCl radiation to the first stokes at high pump energy

An XeCl laser beam has been used to investigate stimulated Raman scattering in H2 and in various H2-foreign gas mixtures. Helium, neon, argon, and nitrogen have been tested as foreign gases. In all the investigated mixtures with 50% of H2, the energy conversion efficiency to the first Stokes (353 nm) was more than 70% higher than that obtained in H2 at the same total pressure (40 bar) and pump energy (60 mJ). The dependence of the energy conversion efficiency on pump beam divergence has also been investigated.