标题： 自发产生的相干性对简并原子系统中左手性的效应 显示英文标题

标题： Effect of spontaneously generated coherence on left-handedness in a degeneracy atomic system

摘要： 对自发产生相干性（SGC）对四能级Y型原子系统中左手性影响进行了理论研究，该系统有两个接近简并的高能级。结果表明，随着SGC强度的增强，原子系统逐渐表现出同时具有负介电常数和负磁导率的左手性，并且折射率随SGC强度的增加而增大。然而，当SGC强度较大时，吸收被SGC效应抑制。当探针场近共振耦合到原子系统时，SGC的出现并不总是使磁导率从正变为负并允许左手行为发生，除非SGC达到较大的强度。 显示英文摘要

摘要： A theoretical investigation is carried out into the effect of spontaneously generated coherence(SGC) on the left-handedness in a four-level Y-type atomic system with two highest nearly degenerate lying levels. It is found, with the spontaneously generated coherence intensity enhancing, the atomic system gradually displays left-handedness with simultaneous negative permittivity and permeability. And the refractive index enhances with the increasing intensity of SGC.However, the absorption is suppressed by the SGC effect when the SGC has a large intensity.When the probe field is near-resonant coupled to the atomic system, the appearance of SGC doesn't always change the permeability from positive to negative and allow for left-handed behavior,unless the SGC reaches a large intensity.