Enhancement of Kerr nonfinearity by multiphoton coherence

We propose a new method of resonant enhancement of optical Kerr nonlinearity that uses multilevel 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 Rb-87 vapor cell by changing the ellipticity of the light. (C) 2003 Optical Society of America.