Abstract

The results on experimental observation of electromagnetically induced transparency (EIT) in four-level N-type scheme are presented [1] The experiments were performed on the D₂ absorption line of ⁸⁷Rb An experimental setup was based on two independent external cavity diode lasers (ECDL) The copropagating orthogonally polarized laser beams were passed through a rubidium cell The frequency of one of the lasers (laser 1) was fixed and tuned to the center of the Doppler broadened group of transitions 5S_1/2(F=2)→5P_3/2(F=1,2,3) The absorption of emission of the laser 1 was measured The frequency of the second laser (laser 2) was scanned across the Doppler broadened transition 5S_1/2(F=1)→5P_3/2(F=0,l,2) In this conditions we observed a conventional single EIT resonance (Fig 1a) in the two photon Raman-type schemes 5s_1/2(f=2)↔ 5P_3/2(F=l)↔ 5S_1/2(F=2) and 5S_1/2(F=l)↔5P_3/2(F=2)↔ 5s_1/2(f=2) for two velocity groups of atoms

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