Superluminal propagation of light in a atomic medium

We manipulated and adjusted the absorption, dispersion, group index, and group velocity in a sodium atomic medium by controlling the strength and collective phase of the driving fields. The group index in these regions is calculated to be [Formula: see text]250,000. The group velocity [Formula: see text] in these locations is measured to be [Formula: see text][Formula: see text]m/s. An investigation is conducted on a negative delay of [Formula: see text]s in the sodium medium. The presence of negative delay and negative group velocity indicates the occurrence of superluminal propagation of light pulses within the medium. The negative group index is increased from [Formula: see text] to [Formula: see text], and the negative delay time is increased from [Formula: see text]s to [Formula: see text]s, with the driving field [Formula: see text] having a Rabi frequency. The work presented in this paper has substantial implications for the fields of gravitational wave detection, radar technology, and temporal cloaks.