A new method of dark resonance excitation on D2 line in 87Rb vapor

A new method based on optical pumping is proposed for increasing the parameters of dark resonance excitation on D2 line in 87Rb vapor. The pumping is provided by linearly polarized two-frequency laser radiation propagating in the direction perpendicular to the probing field directed along the cell with atomic rubidium vapor. This method significantly improves the dark resonance parameters as compared to the case of pumping by a circularly polarized field. Qualitative considerations are confirmed by the results of numerical calculations.