Forced Raman scattering in air by a two-frequency laser beam

Abstract. Stimulated Raman scattering in atmospheric nitrogen has been observed using two copropagating high power laser beams at 1.064 p m and 1.053,um from a neodynium glass laser. This is due to the near coincidence of the beat frequency at 98.2 cm- ' with a rotational line of nitrogen (transition between J = 11 and J = 13) at 99 cm-'. The beams were of total intensity 6 x lo9 Wcm- ' and had a common air path of =30m. Large amplitude Stokes and anti-Stokes sidebands up to one half the pump beam intensity were generated. The observations are compared with a theoretical treatment of the interaction. 1