Electromagnetically induced two-photon transparency in a four-level system of rubidium atom

Abstract

An experimental study of electromagnetically induced two- photon transparency (EITT) in rubidium atomic vapor at room temperature is presented. A four level system is considered, involving the two-photon absorption process 5S 1/2 to 8S 1/2 via an intermediate state 5P 3/2 , and the single- photon control process 5P 3/2 to 5D 5/2 . A controlling pump laser beam is employed to coherently couple the 5P 3/2 and 5D 5/2 states, thus producing two dressed intermediate states, which give rise to destructive interference in the two-photon transition. Fluorescence from 8S 1/2 to 5P 1/2 is used to monitor the 5S 1/2 (Fequals3) to 8S 1/2 (Fequals3) two-photon absorption. An induced two-photon transparency of about 80% has been obtained at resonance; the experimental results are in good agreement with the general theory of Agarwal, when the appropriate spectroscopic parameters are employed.