Multiple Competition Processes Between Stimulated Brillouin and Raman Scattering in a Sulfate Aqueous Solution

Stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) processes from the aqueous solution of MgSO4 have been observed. The experimental results show that there are three different processes in aqueous solution of sulfate: SBS, SRS attributed to the OH bond stretching vibration of water molecules, and SRS attributed to the stretching vibration of sulfate ion (SO42-). The strong and weak sulfate ions determine which one is dominant among the three competition processes. In saturated aqueous solution, it is shown that the SRS process of sulfate ion clearly dominates over the other two stimulated scattering processes. Meanwhile, we have also observed the thermal defocusing phenomenon in saturated aqueous solution at higher pump energy. The results can aid in enhancing the Raman conversion efficiency in liquid scattering media by improving the experimental process.