Stimulated Raman scattering excited in capillary waveguides by tunable radiation

Two-frequency tunable radiation was generated by stimulated Raman scattering in few-mode optical waveguides (benzene-filled quartz capillaries) pumped by a rhodamine 6G laser radiation. The Stokes shift of the Raman band varied when the dye laser radiation was tuned in the range 17700-17100 cm${}^{-1}$. This variation was governed by the position of the Raman band relative to the absorption line of benzene in the region of 16500 cm${}^{-1}$ associated with the sixth harmonic of the $C-H$ valence vibration of benzene.