Investigation of stimulated Raman scattering in gases excited by fourth harmonic of neodymium laser radiation

The results are given of an experimental investigation of stimulated Raman scattering in gaseous hydrogen and deuterium excited fourth neodymium laser harmonic. The harmonic power was stabilized by ensuring that the emission frequency of the master single-mode single-frequency laser was stable to within 0.05 Å. The energy characteristics of the scattered radiation were investigated and the observed features were interpreted on the basis of four-frequency parametric resonance. Stimulated Raman scattering was observed in H₂ at atmospheric pressure. The stimulated Raman gain was determined at the frequencies of the second and fourth harmonics. A good agreement was obtained between the measured cross sections of the spontaneous Raman scattering and those calculated theoretically.