Nonlinear effects due to optical pumping of sodium vapor by single-pass laser beams

Circularly polarized laser beams propagating through sodium vapor and tuned to the buffer gas broadened atomic D1 transition can optically pump sodium atoms into a nonabsorbing groundstate. The corresponding groundstate populations depend on the intensity distribution, the polarization and the magnetic fields. They lead to refractive index gradients along as well as transverse to the laser beam propagation direction and therefore modify the light path giving rise to a number of nonlinear spatiotemporal intensity and polarization pattern creating processes.