Abstract:
In recent years, based on the intense interaction between coherent light and matter, the controllable quantum interference phenomena, such as coherent population trapping, electromagnetically induced transparency and electromagnetically induced absorption, optical hole-burning, have attracted a comprehensive concern. For exploring the controllable characteristics of light absorption involving the coherent hole-burning, a four-level N-type atomic system was proposed, which was driven by a strong coherent light field and two coupling fields with the Doppler broadening thermal rubidium vapor. Via introducing the coupling fields and then adjusting the intensity of the coupling field in such an atomic system, some interesting quantum optical phenomena can be observed. Based on the design of this atomic model, the expression of absorption spectrum of the weak probe light fields was derived via the Laplace transform with the system Hamiltonian equation and density matrices. In the design of optical scheme, the saturated light field was inputted with the same or opposite propagating direction as that of the two coupling light fields, which was opposite the weak probe light field. In such a scheme, six coherent optical hole-burnings and one window based on electromagnetically induced transparency may be realized. With the adjustment of the relevant parameters in terms of the intensities and frequencies of the light fields, the enhancement or weakening of the light absorption can be realized in the absorption spectrum, including the change of the position and number of the optical hole-burning. By the transition of atoms excited by the fields, both electromagnetic induced transparency and electromagnetic induced absorption appeared at the same time. Through the adjustment of light field and the comparison of simulation results, the generation and conversion of the two quantum coherence effects were deeply studied. It is concluded that these results may have a good theoretical guidance for the popular optical quantum storage.