Spatial characteristics of pump and "Stokes" beams under conditions of resonant stimulated Raman scattering in NH3

An investigation was made of the spatial characteristics of the pump and "Stokes" beams under conditions of resonant stimulated Raman scattering by NH₃ in a multipass cell. In spite of the large difference between the wavelengths of the pump and Stokes radiation, some similarity was observed between the output dimensions of their beams. It was found that, in a wide range of frequency tuning, resonant self-interaction influenced strongly the propagation of CO₂ laser radiation and Stokes radiation in a multipass cell.