Electromagnetically induced left-handedness with vacuum-induced coherence
真空诱导相干对电磁感应左手效应的影响

The electromagnetically induced left-handedness in a four-level atomic system associated with a pair of upper excited hyperfine levels has been investigated. The properties of left-handedness with vacuum-induced coherence (VIC) arising from the cross coupling spontaneous emission pathways have also been discussed. The theoretical analyses show that the left-handedness of medium will be enhanced with the increase of VIC effect.