Optical vortices induced in nonlinear multilevel atomic vapors
  In a numerical investigation, we demonstrate the existence and curious evolution of vortices in a ladder-type three-level nonlinear atomic vapor with linear, cubic, and quintic susceptibilities considered simultaneously with the dressing effect. We find that the number of beads and topological charge of the incident beam, as well as its size, greatly affect the formation and evolution of vortices. To determine the number of induced vortices and the corresponding rotation direction, we give common rules associated with the initial conditions coming from various incident beams. 
Yiqi Zhang, Zhenkun Wu, Chenzhi Yuan, Xin Yao, Keqing Lu, Milivoj   Beli\'c, and Yanpeng Zhang
nlin.PS physics.optics