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 87Rb vapor D2-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 circularly-polarized probe beam only, and significant improvement of the dark resonance parameters is found. Qualitative considerations are confirmed by numerical calculations. 
G.Kazakov, I.Mazets, Yu.Rozhdestvensky, G.Mileti, J.Delporte, and   B.Matisov