Amplification of a diffraction-limited Stokes beam by a severely distorted pump.

The feasibility of using a severely aberrated pump beam to amplify effectively without distortion a diffraction-limited Raman beam has been studied. In these experiments the XeCl laser served as the pump and H(2) as the Raman medium. Degradation of the amplified Stokes beam quality with increase in the Raman gain was observed and measured.