Electromagnetically-induced-absorption resonance with high contrast and narrow width in the Hanle configuration

Abstract

The method for observing the high-contrast and narrow-width resonances of\nelectromagnetically induced absorption (EIA) in the Hanle configuration under\ncounterpropagating light waves is proposed. We theoretically analyze the\nabsorption of a probe light wave in presence of counterpropagating one with the\nsame frequency as the function of a static magnetic field applied along the\nvectors of light waves, propagating in a vapour cell. Here, as an example, we\nstudy a "dark" type of atomic dipole transition Fg=1-->Fe=1 in D1 line of 87Rb,\nwhere usually the electromagnetically induced transparency (EIT) can be\nobserved. To obtain the EIA signal one should proper chose the polarizations of\nlight waves and intensities. In contrast of regular schemes for observing EIA\nsignals (in a single travelling light wave in the Hanle configuration or in a\nbichromatic light field consisted of two travelling waves), the proposed scheme\nallows one to use buffer gas to significantly enhance properties of the\nresonance. Also the dramatic influence of atomic transition openness on\ncontrast of the resonance is revealed, that gives great advantage in comparison\nwith cyclic atomic transitions. The obtained results can be interesting in\nhigh-resolution spectroscopy, nonlinear and magneto-optics.\n