Study On Effect Of Intermolecular Fermi Resonance On Raman Scattering

In this paper, stimulated Raman scattering of toluene and m-xylene, mixed solution in liquid core optical fibers was studied. Stimulated Raman scattering in this mixed solution was enhanced by intermolecular Fermi resonance. Spontaneous and stimulated Raman scattering spectrum of the mixed solution were measured. Effect of mixture ratio on Raman scattering cross section, peak intensity and threshold were discussed.The experimental results showed that, in toluene and m-xylene mixed solution with different mixture ratio, the following three modes of vibration were stimulated simultaneously:v1 line with the Raman frequency shift of 1002 cm-1, v2 line with the Raman frequency shift of 2920 cm-1 and 3058 cm-1. First order Stokes threshold of v2 line is lower than second order Stokes threshold of v1 line, and the two Stokes lines in v2 became the major peak in succession under different mixture ratio. We considered the mechanism of this phenomenon was effect of intermolecular Fermi resonance on Raman scattering and presented reasonable interpretation using theory of Raman scattering cross section. The experimental results were identical with theory. SRS in mixed solution has wide perspective in tunable fiber laser, Raman amplifier and etc.