Raman-Ramsey Resonances In Optically Thick Atomic Vapors

We theoretically describe Raman-Ramsey resonances in an optically thick atomic vapor. Some parameters of interest for frequency standard applications, including light-shift, contrast and linewidth of the central Ramsey fringe are calculated at different temperatures of the atomic vapor. Calculations are done for either Cs and Rb vapor cells with buffer gas. The theory is compared to already existing experimental results obtained with Cs cells and predictions are reported for Rb cells.