Asymmetric frequency-tuning behavior of the D1 line hyperfine spectrum of Rb vapor contained in high quality paraffin coated optical cell

Significant modification of the spectrum of the D1 line of 85Rb in optical cells with high quality antirelaxation coating on the walls is studied experimentally and theoretically analyzed. The spectral profiles of hyperfine transitions are found to be significantly dependent on the velocity and the direction of the laser frequency scanning. A physical explanation is proposed for the observed features, which is confirmed by numerical simulations. The effect of small magnetic field on hyperfine spectrum is also discussed.