The on-going program on laser-plasma interaction physics at LULI has led to important progress in the understanding of parametric instabilities by using Thomson scattering of a short wavelength probe beam from plasma waves as a key diagnostic. Stimulated Brillouin Scattering (SBS) spectra have been correlated to the location of ion acoustic. waves in the velocity profile, and SBS reflectivities are in agreement with the convective theory of SBS in randomly distributed speckles.