Dynamic amplification and generation of entangled polaritons in doped media

We have developed a theory that describes the formation of probe-field polaritons under the conditions of strong coupling in the Raman ??-scheme interaction in a Y₂SiO₅ crystal doped with ⁵⁹Pr atoms. The threshold optical pump power for efficient amplification of the probe-field polaritons in a medium consisting of three-level atoms is determined. The onset of strong nonclassical correlations (entanglement) between the light- and dark-state polaritons at the near-threshold pump power is established.