The authors have carried out an experimental study of two-photon excitation via quantum interference in multi-level Rb atomic systems based on the D1 and D2 transitions. The Rb systems can be viewed as quasi-four level systems. The experiments were done in an 87Rb isotope vapor cell. A Ti:sapphire laser was used a coupling laser driving the Rb D2 F = 2 → F′ transition at 780 nm. A four-level model based on the full density-matrix equations and the numerical calculations are in qualitative agreement with the experimental measurements.
