Experimental validation of the linear theory of stimulated Raman scattering driven by a 500-fs laser pulse in a preformed underdense plasma

Measurements of stimulated Raman scattering (SRS) reflectivity produced by the interaction between a short 450-fs, 1.06-μm laser pulse and a large underdense preformed plasma are presented. Experimental results show that the SRS reflectivity sharply increases as the intensity of the interaction beam approaches 1016 W/cm2 from below and saturates for intensities greater than 1017 W/cm2. These results are found to be in very good agreement with those of the initial transient stage theory of SRS starting from thermal equilibrium noise.