We investigate, theoretically and experimentally, the transmission of light through a thermal vapor of three-level ladder-type atoms, in the presence of two counterpropagating control fields. A simple theoretical model predicts the presence of electromagnetically induced absorption in this pure three-level system when the control field is resonant. Experimentally, we use Rb-87 in a large magnetic field of 0.62 T to reach the hyperfine Paschen-Back regime and realize a nondegenerate three-level system. Experimental observations verify the predictions over a wide range of detunings. (C) 2015 Optical Society of America
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