ELECTROMAGNETICALLY INDUCED FOCUSING IN A Λ-TYPE MEDIUM

Electromagnetlcally induced transparency (EIT) in an inhomogenously broadened medium consisting of Λ-type three-level atoms has been analyzed. It is shown that the A system can induce a transparency of the medhun when the probe laser and the coupling laser have the same frequency detunings (including zero). Across the EIT window, the radial variation of the strong coupling laser radiation may lead to electromagnetically induced focusing or defocusing of the weak probe laser at separate probe frequency detuning points.