Stimulated Raman back-scattering from a mm-scale inhomogeneous plasma irradiated with ultra-intense laser pulse

Stimulated Raman scattering (SRS) from a mm-scale inhomogeneous plasma irradiated with an ultra-intense laser pulse was studied. Experimental results show that backward SRS spectral intensities increase with scattered light wavelength up to 1.3 lambda(0) and saturate at longer wavelength, where lambda(0) is the wavelength of the ultra-intense laser. Nonlinear phase mismatch was found to cause the saturation from a fully relativistic nonlinear 1D fluid simulation due to the relativistic mass increase of electron. The total amount of SRS was measured to be less than 3% of the incident laser energy. (C) 2002 American Institute of Physics.