Reversible self-Kerr-nonlinearity in an N-type atomic system through a switching field

TL;DR

This paper demonstrates reversible control of self-Kerr nonlinearity in a four-level atomic system using a switching field, with experimental results supported by numerical simulations and dressed state analysis.

Contribution

It introduces a method to reversibly switch the sign of self-Kerr nonlinearity in an N-type atomic system through a unidirectional change of the switching field.

Findings

Self-Kerr nonlinearity can be switched from negative to positive and back to negative.

Experimental results agree with numerical simulations.

Dressed state analysis explains the observed reversibility.

Abstract

We investigate the self-Kerr nonlinearity of a four-level N-type atomic system in 87Rb and observe its reversible property with the unidirectional increase of the switching field. For the laser arrangement that the probe field interacts with the middle two states, the slope and the sign of the self-Kerr nonlinearity around the atomic resonance can not only be changed from negative to positive, but also can be changed to negative again with the unidirectional increasing of the switching field. Numerical simulation agrees very well with the experimental results and dressed state analysis is presented to explain the experimental results.