Observation of electromagnetically induced absorption in open systems regardless of angular momentum

We report experimental results on electromagnetically induced absorption spectra observed in the system which does not satisfy completely the conditions given by Lezama [Phys. Rev. A 59, 4732 (1999)]. We were able to observe electromagnetically induced absorption signals on all transitions in the Rb D-1 line, where F-g<---->F-e=F-g+/-1 or F-g as well as open systems. These signals were only observed in certain Rabi frequency ranges for the coupling field. Present theoretical models, which are good for the case F-g<---->F-e=F-g+1, considering spontaneous transfer of atomic coherences or populations have not been able to explain our experimental results obtained in both cases F-g<---->F-e=F-g-1 and F-e=F-g.