Influence of the laser excitation linewidth on the parameters of EIA resonances in ⁸⁷Rb

Abstract The influence of the spectral linewidth of single-frequency lasers on the parameters of the electromagnetically induced absorption resonances in rubidium vapour is examined. We use two counter-propagating pump and probe beams to prepare high-contrast magneto-optical resonances in a Hanle-configuration on Rb atoms contained in a paraffin-coated optical cell. Due to the spectral linewidth of the excitation laser, various groups of atoms are involved in creating the coherent resonance, which changes its parameters. The experimental results show the potential of the system to improve the signal-to-noise ratio for more sensitive measurement of weak magnetic fields.