Entanglement in a Raman-driven cascaded system
  The dynamics of a cascaded system that consists of two atom-cavity subsystems is studied by using the quantum trajectory method. Considering the two atom-cavity subsystems driven by a Raman interaction, analytical solutions are obtained. Subsequently, the entanglement evolution between the two atoms is studied, and it is shown that the entanglement can be stored by switching off the Raman coupling. By monitoring the radiation field, the entanglement between the two atoms can be enhanced. 
C. Di Fidio and W. Vogel