Experimental investigations of stimulated Raman scattering in D_2 and D-2/He pumped by the Nd:YAG fourth harmonic laser

The fourth harmonic of a pulsed Nd:YAG laser is used to pump Raman cells filled with D2 and D2/He. The influence of the systemic parameters, such as the pump energy, pressure of pure D2, and addition of He into D2/He, on the energy conversion efficiencies and energy stability of stimulated Raman scattering radiations, have been experimentally studied. It is proved that the energy conversion efficiency and energy stability of S1 is influenced by the intensity and energy stability of pump laser and the pressure of gas medium in Raman cell. On the premise of not lowering the energy stability of the first Stokes radiation (S1, 289.04 nm), it is propitious to increase the energy conversion efficiency of S1 to add proper ratio of He into Raman cell filled with D2. The maximum energy conversion efficiency of S1 reaches 22.1% in D2/He. By experimental analysis, the conditions for optimizing the energy conversion efficiency and energy stability of S1 have been gotten.