Chinese Physics Letters
Negative Refractive Index in a Four-Level Atomic System
Zhang Hong-jun, Gong Shang-Qing, Niu Yue-Ping, Li Ru Xin, Zhizhan Xu
Abstract
We propose a scheme for realizing negative refractive index in a four-level atomic system. It is shown that such a system can simultaneously exhibit negative permittivity and negative permeability in an optical frequency range. Furthermore, by analysing the dispersion property of the left-handed material, we find that the probe beam can be controlled from superluminal to subluminal or vice versa via choosing appropriate parameters.