Study of the Rabi splitting at the 5P3/2 → 5D5/2,3/2 transitions in the 87Rb atom upon cascade excitation in a magnetooptical trap

The level splitting appearing upon cascade excitation of the 5D_5/2 and 5D_3/2 levels of the ⁸⁷Rb atom in a magnetooptical trap is studied experimentally. The 5S_5/2 and 5P_3/2 levels are coupled by a cooling laser field, the Rabi frequency being comparable with the rate of spontaneous decay of the 5P_3/2 level. The experimental spectral profiles are compared with a theoretical model.