Nonresonant parametric amplification of the spontaneous Brillouin-Rayleigh triplet resulting from two-photon absorption

摘要

The thin structures of stimulated Brillouin scattering (SBS) and stimulated temperature scattering (STS) spectral components caused by two-photon heating are analyzed theoretically. In contrast to the linear (single photon) case for two-photon heating, a Stokes SBS component exhibits the spectral shift depending on the pump intensity. Emergence of an anti-Stokes SBS component is possible when the pump intensity is sufficiently high so that the positive two-photon thermal gain may compensate for the negative electrostrictive gain. The spectral compo- nents of STS caused by linear or two-photon absorption (essentially different linear or two-photon STS-2) possess the same thin structures.