Polarization effects in the interaction between multi-level atoms and two optical fields

摘要

Polarized velocity selective spectra for rubidium atoms in a room temperature cell are presented. The experiments were performed in the lambda configuration (D2 manifold) and in the.. 5s -> 5p(3/2) -> 5d(j) ladder configuration. For the lambda configuration the effect of the probe beam intensity in the absorption and polarization spectra are compared with results of a rate equation approximation. Good overall agreement between experiment and theory is found. The results indicate different saturation rates for each of the atomic transitions. Distinctive polarization signals with hyperfine-resolved components are found for the ladder 5d(3/2) and 5d(5/2) upper states. Fluorescence detection of the 420 nm that results from the second step in the cascade decay 5d(j) -> 6p(j) -> 5s was used in the ladder experiments. This fluorescence was also used for the detection of the 5p(3/2) -> 6p(3/2) electric dipole forbidden transition in atomic rubidium that occurs at 911 nm. The 6p(3/2) hyperfine structure was resolved in this continuous wave, non-dipole excitation.