Effect of spontaneously generated coherence on left-handedness in a degeneracy atomic system
S.-C. Zhao
Physics department, Kunming University of Science and Technology, 650093 Kunming, China
Abstract
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.