Stimulated Raman Scattering of a Modulated Laser Beam in Air: a Perturbation Approach

Stimulated Raman scattering (SRS) of a third-harmonic beam of a high-power laser in air is analysed by using a perturbation approach. It is found that intensity modulations of the third-harmonic beam, resulting from the surface ripple of nonlinear crystal, can be significantly enhanced due to SRS, and the gain of instability increases with the spatial period of modulation. Numerical simulations based on the nonlinear coupled-wave equations verify the validity of the perturbation approach.