Modulation of stimulated Brillouin scattering and stimulated temperature scattering spectral components by two-photon heating

摘要

The effects of linear (single-photon) and two-photon heating to the thin structures of the stokes and anti-stokes spectral components of stimulated Brillouin scattering (SBS) and stimulated temperature scattering (STS) are compared. The thin structures of the linear and two-photon STS-2 possess the same shapes. For the Fabry-Perot etalon based spectrum analyzer the linear and two-photon STS-2 components are experimentally indistinguishable not only from one another, but also from the STS-1 component. To reach the higher spectral resolution methods of heterodyning and intensity fluctuations correlation should be used. In contrast to a linear (single-photon) case for two-photon heating a stokes SBS component exhibits the spectral shift depending on the pump intensity. Emergence of the anti-stokes SBS component is possible when the pump intensity is sufficiently high so that the positive two-photon thermal gain may compensate the negative electrostrictive gain.