LAUSR

Magnetically induced Fg = 2 → Fe = 4 transitions corresponding to the 85Rb D2 line in the case of the σ+ circularly polarized radiation have been used for the first time to form optical dark resonances in strong magnetic fields up to 1 kG under electromagnetically induced transparency conditions. A 1.5-μm-thick cell filled with Rb atomic vapor has been used. The probabilities of two of five magnetically induced transitions, which are efficiently formed only with the σ+-polarized radiation, in the magnetic field range of 0.2–1 kG exceed the probabilities of “ordinary” atomic transitions. For this reason, it is appropriate to use them in Λ systems for the formation of the dark resonance. The following rule has been established: for the formation of the dark resonance in a Λ system with the use of the σ+-polarized probe radiation at the frequencies of magnetically induced transitions, the radiation of the coupling laser should also be σ+ polarized; the dark resonance is not formed if the radiation of the coupling laser is σ– polarized, which is confirmed by the calculated theoretical curve. A significant advantage of magnetically induced resonances for electromagnetically induced transparency compared to ordinary atomic transitions corresponding to the 85Rb D2 line has been demonstrated. The formation of dark resonances in strong magnetic fields, when their frequency is shifted by several gigahertzs, can be applied in practice.