Laser Induced Gas Vortices
  Properly polarized and correctly timed femtosecond laser pulses have been demonstrated to create rotational states with a preferred sense of rotation. We show that due to conservation of angular momentum, collisional relaxation of these unidirectionally rotating molecules leads to the generation of macroscopic vortex flows in the gas. The emerging velocity field converges to a self-similar Taylor vortex, and repeated laser excitations cause a continuous stirring of the gas. 
Uri Steinitz, Yehiam Prior and Ilya Sh. Averbukh
physics.optics physics.chem-ph physics.flu-dyn quant-ph