Continuous-Wave Multifrequency Laser Emission Generated Through Stimulated Raman Scattering and Four-Wave Raman Mixing in an Optical Cavity

The frequency of a continuous-wave laser was converted via high-order stimulated Raman scattering and four-wave Raman mixing in a high-finesse optical cavity. The threshold for the generation of a Stokes beam was determined by the Raman gain coefficient and the loss in the cavity. The intracavity power of the second-order Stokes beam increased with an increase in pump power, whereas the power of the first-order Stokes beam stayed constant. The output power of the anti-Stokes beam was low when there was a phase mismatch between the pump and the first-order Stokes beam. The anti-Stokes beam, however, was enhanced by decreasing the pressure of the Raman active medium. This suggests that the dispersion can be used to improve the efficiency of the intracavity four-wave Raman mixing.