Journal of Atomic and Molecular Physics
Dispersion properties in a cascade three level system from a thin atomic vapor film
Yuanyuan Li
Abstract
The unexpected dispersion properties of transmitting wave from a thin vapor of cascade three level atoms confined between two dielectric walls are theoretically discussed.The line shapes exhibit a Dicke-narrowing type sub-Doppler structure as a result of the slowest atoms contribution and the velocity selection in pump-probe regime.It is also found that there is a strong reduction of the group velocity of light shown by the fast variation of the dispersion in the vicinity of resonance.Because of velocity selection,the line-widths are narrower and the reduction of the group velocity is more manifest in counter-propagation regime than they are in co-propagation regime.One also notes that there are two superimposed dispersion curves,the first of which corresponds to the optics pumping,and the other(the steeper) one to possible electromagnetically induced transparency.