Study of Stokes generation in Nd：YAG fourth harmonic(266nm) pumped H2

The stimulated Raman scattering (SRS) in H2 pumped by the fourth harmonic of Nd:YAG laser (266nm) is investigated.The wavelength of the pump laser has been shifted into 200nm～595nm wavelength region.When the pump laser is operated at laser energy of 22mJ,five orders of Stokes and three orders of anti-Stokes have been observed.The corresponding output energy of the first order Stokes (299nm),the second order Stokes (341nm) and the first order anti-Stokes (239nm) was 3mJ,6.1mJ and 0.8mJ respectively.The relationships between the pressure of H2 and energy of each Stokes were investigated.Moreover,the circle beam spots have been observed.