Changes in the gain of stimulated Raman scattering of neodymium laser radiation by rotational levels of gaseous hydrogen

Measurements were made of the gain of stimulated Raman scattering by rotational levels of gaseous hydrogen in the case when the directions of rotation of the polarizations of the pump (neodymium laser) radiation and of the Stokes signal coincided or were opposite. The dependence of the gain on the hydrogen pressure was found. It was found that a ~50% efficiency of conversion into just the first Stokes component could be acheived without any special measures to suppress the second component.