Specific appearing of stimulated Raman scattering in dyed multiple scattering media

Abstract

We have discovered that Stokes lines of dye stimulated Raman scattering (SRS) in a multiple scattering media (MSM) appear in strict sequence: each line appears after occurrence of shorter wave one. Although outwardly this sequence is similar to the lines occurrence of plain SRS but its origin and mechanism is different. The main difference is that SRS in MSM is part of coupled process SRS and random lasing (RL) and therefore it is stimulated by RL. This difference causes specific characteristics of SRS in MSM. In contrast to plain SRS where sequentially appearing SRS lines correspond to consecutive Stokes component of the same molecule vibration, all SRS lines in dyed MSM correspond to first Stokes components of different bonds of dye molecule. Consecutive order of SRS lines appearing in MSM is caused not pumping of next SRS component by radiation of previous one but by RL spectrum spreading to the long wave direction under pump intensity.