Characteristics of an interferometer with stimulated Brillouin scattering mirrors

An interferometer with wavefront-reversing mirrors based on stimulated Brillouin scattering was used to investigate the spatial structure of the Stokes radiation. A Stokes wave formed as a result of stimulated Brillouin scattering in a light pipe included fields with configurations reversed relative to the pump radiation and propagating not exactly backward but at certain angles. These fields were concentrated in a background pedestal for which the divergence increased on increase in the gain increment Γ_c at the correlation length. For a fixed Γ_c the relationship between the energy of the Stokes signal (reproducing exactly the spatial structure of the pump radiation) and the energy of the background pedestal varied randomly from pulse to pulse, resulting in a strong dispersion of the energy of the Stokes wave measured in both interferometer arms.