Influence of the Stark modulation of molecular vibrations on stimulated Raman scattering

Equations are derived for the susceptibilities in the stimulated Raman scattering of double-mode laser radiation. The Stark shift of the molecular vibration frequency may oscillate at the frequency of the beats between the modes. These oscillations modulate the molecular vibrations and the scattered radiation spectrum acquires lines separated from one another by the beat frequency. It is shown that an increase in the intensity of the exciting radiation results in the equalization of the gain for an increasing number of the scattered radiation lines. The maximum value of the gain falls, so that the efficiency of the stimulated Raman scattering decreases. The components of the discrete structure of the scattered radiation increase in number because of the amplification of the spontaneous scattering noise. It is shown that the formation of a discrete structure because of parametric processes has special features under the Stark modulation conditions: When the intensity of the exciting radiation is increased, the strongest interaction shifts to the neighboring structure components, located far from the center of the undisplaced line.