Slow-light solitons revisited
  We investigate propagation of slow-light solitons in atomic media described by the nonlinear $\Lambda$-model. Under a physical assumption, appropriate to the slow light propagation, we reduce the $\Lambda$-scheme to a simplified nonlinear model, which is also relevant to 2D dilatonic gravity. Exact solutions describing various regimes of stopping slow-light solitons can then be readily derived. 
A.V. Rybin, I.P. Vadeiko, and A.R. Bishop