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 1$0^{16}$ W/c${\mathrm{m}}^2$ from below and saturates for intensities greater than 1$0^{17}$ W/c${\mathrm{m}}^2$. 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.