Acta Sinica Quantum Optica

The Research of Electromagnetically induced transparency and giant Kerr nonlinearity in a four-level Y-type atomic system

Yanpeng Zhang

Published Jan 1, 2008• 0 citations

Abstract

A theoretical investigation is carried out into the effect of applied coherent fields on electromagnetically induced transparency(EIT) and Kerr nonlinearity in the four-level Y-type energy atom system.It is found that the Absorption curve of the atom system changes from one EIT window to a gain interval which has two transparency points when the intensity of coupling field and pumping field changes from equality to inequality.The position of transparency points,the magnitude of gain value together with the width of gain interval are all closely connected with the changed Rabi frequency of applied fields.It is also found that Kerr nonlinearity is enhanced but accompanied by linear Absorption when applied fields are all weak and their relative intensity reduces.When the intensity of applied fields is enlarged,Kerr nonlinearity is enhanced significantly and its peak moves to the position of transparency point with the enlargement of their relative intensity.That is to say,giant Kerr nonlinearity accompanied by vanishing linear Absorption is obtained.Finally,we find that the effect of the intensity variation of the pumping field on the enhancement of Kerr nonlinearity is more remarkable than that of the coupling field.

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