Ground state interference spectra of a three-level atom induced by a bichromatic field

Abstract

The author has considered the interference spectra arising from the competition between short- and long-lifetime excitations, which have been induced in the ground state of a three-level atom by a strong and a weak laser field, respectively. The atom is supposed to have a strong and a weak transition leading to an electric-dipole-allowed excited state and to a metastable excited state, respectively. Expressions have been derived for the spectral functions describing the induced spectra in the ground state of the atom in the low- and high-intensity limits of a strong laser field. The competition between the short- and the long-lifetime excitations results in the decrease of the intensity of the short-lifetime excitation near the centre of the peak by an amount equal to 50% of its original value. The computed spectra have been presented graphically and discussed. It is shown that the decrease of the intensity of the short-lifetime excitation may provide a measure of the width of the long-lifetime excitation.