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 text250,000. The group velocity Formula: see text in these locations is measured to be Formula: see textFormula: see textm/s. An investigation is conducted on a negative delay of Formula: see texts 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 texts to Formula: see texts, 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.