Table of Contents
Journal of Atomic, Molecular, and Optical Physics
Volume 2009, Article ID 382764, 4 pages
Research Article

The Kerr Nonlinearity in an N-Type Four-Level System via Spontaneously Generated Coherence

1Department of Physics, Northwest University, Xi'an 710069, China
2State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China

Received 9 January 2009; Revised 2 April 2009; Accepted 4 August 2009

Academic Editor: Nir Davidson

Copyright © 2009 Yingjie Du et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The Kerr nonlinearity is investigated in an N-type four-level atomic system whose both supper levels are degenerated or nearly degenerate. It is found that the spontaneously generated coherence as a result of the degenerate levels can change the Kerr nonlinearity dramatically depending on the angle between two spontaneous channels. In addition, we discover that the probe field makes its own contribution to the nonlinearity in comparison to indifference in general three-level systems.