High-contrast dark resonance on the D2-line of 87Rb in a vapor cell with different directions of the pump-probe waves

We propose a novel method enabling to create a high-contrast dark resonance in the Rb-87 vapor D-2-line. The method is based on an optical pumping of atoms into the working states by a two-frequency, linearly-polarized laser radiation propagating perpendicularly to the probe field. This new scheme is compared to the traditional scheme involving the sigma(+)-polarized probe beam only, and significant improvement of the dark resonance parameters is found. Qualitative considerations are confirmed by numerical calculations.