Applied Physics B, Lasers and Optics vol:83 issue:4 pages:635-641
In one of our previous papers (R.N. Shakhmuratov et al. Appl. Phys. B. 81, 883 (2005)) we presented a new type of spatiotemporal interference of gamma radiation propagating in a resonant medium. The excitation scheme consists of two identical V-schemes, each being formed by one type of the transition: one is induced only by the left circular polarized field and the other by the right circular polarized field. The coupling of these V-schemes through level crossing allows resonant scattering of a photon in the forward direction with a change of its polarization. As a result the radiation field, which is resonant with a transition from the ground state to one of the two sublevels of the excited state, develops in a particular combination of radiation fields with left and right circular polarizations, called a normal mode. This combination is much less absorbed in subsequent layers of the absorber. For identical V-schemes, the structure of the modes is fairly simple. In this paper, we show that a similar reduction of absorption is realized for non-identical V-schemes, differing in transition strengths. The structure of the normal modes is found and they have a more complicated form. This general case is actually realized in a level crossing experiment in gamma optics.