The absorption and dispersion properties of a Kobrak-Rice 5-level quantum system are investigated. It is shown that the dressed states of such a system are phase-dependent. It is also demonstrated that the absorption, dispersion and group index can be controlled by either the intensity or relative phase of driving fields. Moreover, we have shown that by applying an incoherent pumping field the absorption doublet switches to gain doublet, and the absorption free superluminal light propagation appears which can be used in the transfer of information process.
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