Enhancement of Kerr nonlinearity via multi-photon coherence
  We propose a new method of resonant enhancement of optical Kerr nonlinearity using multi-level atomic coherence. The enhancement is accompanied by suppression of the other linear and nonlinear susceptibility terms of the medium. We show that the effect results in a modification of the nonlinear Faraday rotation of light propagating in an Rb87 vapor cell by changing the ellipticity of the light. 
A.B. Matsko (1), I. Novikova (1), G.R. Welch (1), M.S. Zubairy (1 and   2) ((1) Department of Physics and Institute for Quan...