Coherence effects in ordinary Raman scattering in the presence of two-photon resonance

In the presence of coherent saturated near-resonant two-photon excitation, the ordinary Raman scattering line is replaced by a dynamic Stark shifted or Stark split doublet, and Rabi nutations appear in the time-resolved ordinary Raman spectrum. The relative intensity of the peaks of the doublet depends on the shape and on the average frequency of the exciting pulse. Striking new features arise from the interfering contributions of the upper and lower states of the two-photon transition to the Raman scattering process. The theory is applied to Raman scattering in atomic Na in the presence of the 3 ²S₁2/(F=1, M_F=1) to 4²D ₃2,5/2/(F=3,M_F=3) two-photon resonances.