Optimizing the on-axis anti-Stokes generation of four-wave stimulated Raman scattering with a focused pump beam

The influence of the focusing angle of the pump radiation on the generation of the on-axis anti-Stokes component from four-wave stimulated Raman scattering (SRS) was researched. It was found that there is an optimal focusing angle, which corresponds to the maximum conversion efficiency. This angle is close to the phase-matching angle of four-wave parametric anti-Stokes generation. At optimal conditions, 10% energy conversion efficiency to the on-axis anti-Stokes radiation was achieved by SRS of picosecond laser pulses in liquid carbon tetrachloride.