Effect of changing the initial excitation spatial profile on the radiation emitted from a slab of two-level atoms

For the purpose of investigating the effect of the initial spatial distribution of the excited atoms in a slab on its emission characteristics, I compute, for different configurations of a 1D system consisting initially of equal number of atoms in the excited and ground states, the emitted field at both the front-end and back-end of the slab. I show that depending on the spatial configuration of the excited atoms/ground states atoms in the slab, the system may be at later times in a metastable state, emits equally from both end faces or emits preferentially from only one of these. These qualitatively distinct states of the system are due to the different spatial coherence present in each case, and/or the difference in the strong inter-modal coupling present and resulting from the nonlinearity in the Maxwell–Bloch equations.