Eur. Phys. J. D 42, 483-488 (2007)
https://doi.org/10.1140/epjd/e2007-00040-x

Effects of relative phase in an open ladder system without incoherent pumping

¹ College of Physics and Electronics, Shandong Normal University, Jinan, 250014, P.R. China
² Communication College, Shandong Normal University, Jinan, 250014, P.R. China
³ Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Shanghai, 201800, P.R. China

Corresponding author: ^a xjfan108@yahoo.com.cn

Received: 4 September 2006
Revised: 23 December 2006
Published online: 23 February 2007

Abstract

We studied effects of the relative phase between the probe and driving fields on the absorption and dispersion properties in an open three-level ladder system with spontaneously generated coherence but without incoherent pumping. It is shown that by the phase controlling, switching from absorption to lasing without inversion (LWI) and enhancing remarkablely LWI gain can be realized; large index of refraction with zero absorption and the electromagnetically induced transparency can be obtained. We also find that varying the atomic injection and exit rates has a considerable influence on the phase dependent-absorption property of the probe field, existent of the atomic injection and exit rates gives the necessary condition of the realization of LWI, getting LWI is impossible in the corresponding closed system without incoherent pumping.