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

Stimulated Raman scattering in atmospheric nitrogen has been observed using two copropagating high power laser beams at 1.064 mu m and 1.053 mu m from a neodymium glass laser. This is due to the near coincidence of the beat frequency at 98.2 cm-1 with a rotational line of nitrogen (transition between J=11 and J=13) at 99 cm-1. The beams were of total intensity 6*109 W cm-2 and had a common air path of approximately=30 m. 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.