G. Wasik et al., Competition of dark states: Optical resonances with anomalous magnetic field dependence - art. no. 051802, PHYS REV A, 6405(5), 2001, pp. 1802
A different type of optical resonance has been observed in Doppler-free sat
urated absorption spectroscopy when the pump beam has elliptical polarizati
on slightly deviating from the sigma (+) and the probe has sigma (-) polari
zation. An interpretation in terms of competition between two trap states a
nd a dressed-atom model is presented. The observed extreme sensitivity of t
he resonance frequency to the external magnetic field is attributed to the
"scissors effect" of the dressed states' crossing point.