Abstract

The study of fluorescence spectra under the action of resonant laser wave plays a fundamental role in the understanding of processes of radiation interaction with matter. It is well known (see, e.g., Ref. ¹) that in the case of a two-level medium at low density the shape of such spectrum looks as a symmetrical triplet with sidebands separated from a central component by the generalized Rabi frequency. However, in the case of a strong laser field, the two-level approximation of real atomic systems very often is not adequate, since it is necessary to take into account the influence of the nearest levels. In the alkali metal vapors it implies that the Rabi frequency is order of doublet splitting value. In the present paper, as far as we known, we report on the first experimental observation of many-component resonance fluorescence spectra of three-level atomic system in the intense laser field caused by the Rabi splitting of the ground 3S and two exited 3P states of sodium atom on six quasi-energy levels (see Fig. 1). It follows from Fig. 1 that in the fluorescence spectra of the three-level medium must be observed up to six sidebands at the frequencies ${\omega }_{\text{j}}^{\pm }={\omega }_{\text{L}}\pm {\Omega }_{\text{j}}^{\text{'}}$ ( ${\Omega }_{\text{j}}^{\text{'}}$ are the generalized Rabi frequencies of the three-level system,²ω_Lis the laser frequency) and three degenerated components at ω_L.

© 1994 IEEE