Increased Saturated Levels of Stimulated Brillouin Scattering of a Laser by Seeding a Plasma with an External Light Source

The reflectivity of laser light due to stimulated Brillouin scattering (SBS) from long-scale plasmas normally saturates when the laser intensity is increased sufficiently. Nevertheless a significant increase in the SBS reflectivity back into the beam cone results from a subtle change in the target geometry, done for the purpose of seeding SBS. The key element is apparently the injection into the plasma of a modest external electromagnetic seed at a wavelength near that of the scattered light. {copyright} {ital 1998} {ital The American Physical Society}