Coherent spectroscopy of the ⁸⁷Rb F_g=1→ F_e=0 closed transition

This paper has observed linewidth narrowing of dark states in rubidium cell by using the Hanle configuration. The reduction of the coherent resonance width under the transition of ⁸⁷Rb F_g=1 → F_e=0 is observed and the qualitative explanation about its mechanism is presented. Multiple subnatural width dips are obtained with a linearly polarized laser beam for the transitions of ⁸⁷Rb F_g=1 → F_e=0, 1, 2. The feature of negative and positive slope, namely dispersionlike feature, is observed in the transmitted light.