A new effect is demonstrated in which a laser pulse can be made to induce a Kerr effect only at Raman-shifted frequencies. This permitted the observation of a Raman spectrum with a single dye-laser pulse. The pulse power required is a small fraction of that required to produce stimulated instabilities. The spectral information emerges in a coherent beam, phase matching is not necessary, and spectra can be obtained at any scattering angle.

• Received 18 November 1975

DOI:https://doi.org/10.1103/PhysRevLett.36.189