Electromagnetically induced one-photon and two-photon transparency in rubidium atoms

We investigate electromagnetically induced transparency (EIT) for one-photon and resonant two-photon transitions in rubidium atomic vapors. One-photon transparency is obtained in the 5S-5P-5D three level ladder system. At the same time, we study electromagnetically induced transparency in the two-photon transition (EITT) from the 5S to the 7S state resonant with the 5P intermediate state, when the latter is coupled to the 5D state by a control beam. The dependence of the transparency profile on the controlling laser intensity, linewidth, and detuning is investigated. Experimental results are obtained for isotopes Rb-85 and Rb-87 characterized by different hyperfine structures. Our findings for both the one-photon and the resonant two-photon transparency agree well with the prediction from three and four-level theory, respectively, with independently determined spectroscopic parameters. (C) 2002 Elsevier Science B.V. All rights reserved.